darling-xnu/osfmk/kern/zalloc.c
2023-05-16 21:41:14 -07:00

8974 lines
242 KiB
C

/*
* Copyright (c) 2000-2020 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* @OSF_COPYRIGHT@
*/
/*
* Mach Operating System
* Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
/*
*/
/*
* File: kern/zalloc.c
* Author: Avadis Tevanian, Jr.
*
* Zone-based memory allocator. A zone is a collection of fixed size
* data blocks for which quick allocation/deallocation is possible.
*/
#define ZALLOC_ALLOW_DEPRECATED 1
#if !ZALLOC_TEST
#include <mach/mach_types.h>
#include <mach/vm_param.h>
#include <mach/kern_return.h>
#include <mach/mach_host_server.h>
#include <mach/task_server.h>
#include <mach/machine/vm_types.h>
#include <mach/vm_map.h>
#include <mach/sdt.h>
#include <kern/bits.h>
#include <kern/startup.h>
#include <kern/kern_types.h>
#include <kern/assert.h>
#include <kern/backtrace.h>
#include <kern/host.h>
#include <kern/macro_help.h>
#include <kern/sched.h>
#include <kern/locks.h>
#include <kern/sched_prim.h>
#include <kern/misc_protos.h>
#include <kern/thread_call.h>
#include <kern/zalloc_internal.h>
#include <kern/kalloc.h>
#include <prng/random.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_compressor.h> /* C_SLOT_PACKED_PTR* */
#include <pexpert/pexpert.h>
#include <machine/machparam.h>
#include <machine/machine_routines.h> /* ml_cpu_get_info */
#include <os/atomic.h>
#include <libkern/OSDebug.h>
#include <libkern/OSAtomic.h>
#include <libkern/section_keywords.h>
#include <sys/kdebug.h>
#include <san/kasan.h>
#if KASAN_ZALLOC
/*
* Set to 0 to debug poisoning and ZC_ZFREE_CLEARMEM validation under kasan.
* Otherwise they are double-duty with what kasan already does.
*/
#define ZALLOC_ENABLE_POISONING 0
#define ZONE_ENABLE_LOGGING 0
#elif DEBUG || DEVELOPMENT
#define ZALLOC_ENABLE_POISONING 1
#define ZONE_ENABLE_LOGGING 1
#else
#define ZALLOC_ENABLE_POISONING 1
#define ZONE_ENABLE_LOGGING 0
#endif
#if __LP64__
#define ZALLOC_EARLY_GAPS 1
#else
#define ZALLOC_EARLY_GAPS 0
#endif
#if DEBUG
#define z_debug_assert(expr) assert(expr)
#else
#define z_debug_assert(expr) (void)(expr)
#endif
extern void vm_pageout_garbage_collect(int collect);
/* Returns pid of the task with the largest number of VM map entries. */
extern pid_t find_largest_process_vm_map_entries(void);
/*
* Callout to jetsam. If pid is -1, we wake up the memorystatus thread to do asynchronous kills.
* For any other pid we try to kill that process synchronously.
*/
extern boolean_t memorystatus_kill_on_zone_map_exhaustion(pid_t pid);
extern zone_t vm_map_entry_zone;
extern zone_t vm_object_zone;
#define ZONE_MIN_ELEM_SIZE sizeof(uint64_t)
#define ZONE_MAX_ALLOC_SIZE (32 * 1024)
struct zone_page_metadata {
/* The index of the zone this metadata page belongs to */
zone_id_t zm_index : 11;
/* Whether `zm_bitmap` is an inline bitmap or a packed bitmap reference */
uint16_t zm_inline_bitmap : 1;
/*
* Zones allocate in "chunks" of zone_t::z_chunk_pages consecutive
* pages, or zpercpu_count() pages if the zone is percpu.
*
* The first page of it has its metadata set with:
* - 0 if none of the pages are currently wired
* - the number of wired pages in the chunk (not scaled for percpu).
*
* Other pages in the chunk have their zm_chunk_len set to
* ZM_SECONDARY_PAGE or ZM_SECONDARY_PCPU_PAGE depending on whether
* the zone is percpu or not. For those, zm_page_index holds the
* index of that page in the run.
*/
uint16_t zm_chunk_len : 4;
#define ZM_CHUNK_LEN_MAX 0x8
#define ZM_SECONDARY_PAGE 0xe
#define ZM_SECONDARY_PCPU_PAGE 0xf
union {
#define ZM_ALLOC_SIZE_LOCK 1u
uint16_t zm_alloc_size; /* first page only */
uint16_t zm_page_index; /* secondary pages only */
};
union {
uint32_t zm_bitmap; /* most zones */
uint32_t zm_bump; /* permanent zones */
};
zone_pva_t zm_page_next;
zone_pva_t zm_page_prev;
};
static_assert(sizeof(struct zone_page_metadata) == 16, "validate packing");
__enum_closed_decl(zone_addr_kind_t, bool, {
ZONE_ADDR_FOREIGN,
ZONE_ADDR_NATIVE,
});
#define ZONE_ADDR_KIND_COUNT 2
/*!
* @typedef zone_element_t
*
* @brief
* Type that represents a "resolved" zone element.
*
* @description
* This type encodes an element pointer as a tuple of:
* { chunk base, element index, element protection }.
*
* The chunk base is extracted with @c trunc_page()
* as it is always page aligned, and occupies the bits above @c PAGE_SHIFT.
*
* The low two bits encode the protection mode (see @c zprot_mode_t).
*
* The other bits encode the element index in the chunk rather than its address.
*/
typedef struct zone_element {
vm_offset_t ze_value;
} zone_element_t;
/*!
* @typedef zone_magazine_t
*
* @brief
* Magazine of cached allocations.
*
* @field zm_cur how many elements this magazine holds (unused while loaded).
* @field zm_link linkage used by magazine depots.
* @field zm_elems an array of @c zc_mag_size() elements.
*/
typedef struct zone_magazine {
uint16_t zm_cur;
STAILQ_ENTRY(zone_magazine) zm_link;
zone_element_t zm_elems[0];
} *zone_magazine_t;
/*!
* @typedef zone_cache_t
*
* @brief
* Magazine of cached allocations.
*
* @discussion
* Below is a diagram of the caching system. This design is inspired by the
* paper "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and
* Arbitrary Resources" by Jeff Bonwick and Jonathan Adams and the FreeBSD UMA
* zone allocator (itself derived from this seminal work).
*
* It is divided into 3 layers:
* - the per-cpu layer,
* - the recirculation depot layer,
* - the Zone Allocator.
*
* The per-cpu and recirculation depot layer use magazines (@c zone_magazine_t),
* which are stacks of up to @c zc_mag_size() elements.
*
* <h2>CPU layer</h2>
*
* The CPU layer (@c zone_cache_t) looks like this:
*
* ╭─ a ─ f ─┬───────── zm_depot ──────────╮
* │ ╭─╮ ╭─╮ │ ╭─╮ ╭─╮ ╭─╮ ╭─╮ ╭─╮ │
* │ │#│ │#│ │ │#│ │#│ │#│ │#│ │#│ │
* │ │#│ │ │ │ │#│ │#│ │#│ │#│ │#│ │
* │ │ │ │ │ │ │#│ │#│ │#│ │#│ │#│ │
* │ ╰─╯ ╰─╯ │ ╰─╯ ╰─╯ ╰─╯ ╰─╯ ╰─╯ │
* ╰─────────┴─────────────────────────────╯
*
* It has two pre-loaded magazines (a)lloc and (f)ree which we allocate from,
* or free to. Serialization is achieved through disabling preemption, and only
* the current CPU can acces those allocations. This is represented on the left
* hand side of the diagram above.
*
* The right hand side is the per-cpu depot. It consists of @c zm_depot_count
* full magazines, and is protected by the @c zm_depot_lock for access.
* The lock is expected to absolutely never be contended, as only the local CPU
* tends to access the local per-cpu depot in regular operation mode.
*
* However unlike UMA, our implementation allows for the zone GC to reclaim
* per-CPU magazines aggresively, which is serialized with the @c zm_depot_lock.
*
*
* <h2>Recirculation Depot</h2>
*
* The recirculation depot layer is a list similar to the per-cpu depot,
* however it is different in two fundamental ways:
*
* - it is protected by the regular zone lock,
* - elements referenced by the magazines in that layer appear free
* to the zone layer.
*
*
* <h2>Magazine circulation and sizing</h2>
*
* The caching system sizes itself dynamically. Operations that allocate/free
* a single element call @c zone_lock_nopreempt_check_contention() which records
* contention on the lock by doing a trylock and recording its success.
*
* This information is stored in the @c z_contention_cur field of the zone,
* and a windoed moving average is maintained in @c z_contention_wma.
* Each time a CPU registers any contention, it will also allow its own per-cpu
* cache to grow, incrementing @c zc_depot_max, which is how the per-cpu layer
* might grow into using its local depot.
*
* Note that @c zc_depot_max assume that the (a) and (f) pre-loaded magazines
* on average contain @c zc_mag_size() elements.
*
* When a per-cpu layer cannot hold more full magazines in its depot,
* then it will overflow about 1/3 of its depot into the recirculation depot
* (see @c zfree_cached_slow(). Conversely, when a depot is empty, then it will
* refill its per-cpu depot to about 1/3 of its size from the recirculation
* depot (see @c zalloc_cached_slow()).
*
* Lastly, the zone layer keeps track of the high and low watermark of how many
* elements have been free per period of time (including being part of the
* recirculation depot) in the @c z_elems_free_min and @c z_elems_free_max
* fields. A weighted moving average of the amplitude of this is maintained in
* the @c z_elems_free_wss which informs the zone GC on how to gently trim
* zones without hurting performance.
*
*
* <h2>Security considerations</h2>
*
* The zone caching layer has been designed to avoid returning elements in
* a strict LIFO behavior: @c zalloc() will allocate from the (a) magazine,
* and @c zfree() free to the (f) magazine, and only swap them when the
* requested operation cannot be fulfilled.
*
* The per-cpu overflow depot or the recirculation depots are similarly used
* in FIFO order.
*
* More importantly, when magazines flow through the recirculation depot,
* the elements they contain are marked as "free" in the zone layer bitmaps.
* Because allocations out of per-cpu caches verify the bitmaps at allocation
* time, this acts as a poor man's double-free quarantine. The magazines
* allow to avoid the cost of the bit-scanning involved in the zone-level
* @c zalloc_item() codepath.
*
*
* @field zc_alloc_cur denormalized number of elements in the (a) magazine
* @field zc_free_cur denormalized number of elements in the (f) magazine
* @field zc_alloc_elems a pointer to the array of elements in (a)
* @field zc_free_elems a pointer to the array of elements in (f)
*
* @field zc_depot_lock a lock to access @c zc_depot, @c zc_depot_cur.
* @field zc_depot a list of @c zc_depot_cur full magazines
* @field zc_depot_cur number of magazines in @c zc_depot
* @field zc_depot_max the maximum number of elements in @c zc_depot,
* protected by the zone lock.
*/
typedef struct zone_cache {
uint16_t zc_alloc_cur;
uint16_t zc_free_cur;
uint16_t zc_depot_cur;
uint16_t __zc_padding;
zone_element_t *zc_alloc_elems;
zone_element_t *zc_free_elems;
hw_lock_bit_t zc_depot_lock;
uint32_t zc_depot_max;
struct zone_depot zc_depot;
} *zone_cache_t;
static __security_const_late struct {
struct zone_map_range zi_map_range[ZONE_ADDR_KIND_COUNT];
struct zone_map_range zi_meta_range; /* debugging only */
struct zone_map_range zi_bits_range; /* bits buddy allocator */
/*
* The metadata lives within the zi_meta_range address range.
*
* The correct formula to find a metadata index is:
* absolute_page_index - page_index(MIN(zi_map_range[*].min_address))
*
* And then this index is used to dereference zi_meta_range.min_address
* as a `struct zone_page_metadata` array.
*
* To avoid doing that substraction all the time in the various fast-paths,
* zi_meta_base are pre-offset with that minimum page index to avoid redoing
* that math all the time.
*
* Do note that the array might have a hole punched in the middle,
* see zone_metadata_init().
*/
struct zone_page_metadata *zi_meta_base;
} zone_info;
/*
* Initial array of metadata for stolen memory.
*
* The numbers here have to be kept in sync with vm_map_steal_memory()
* so that we have reserved enough metadata.
*
* After zone_init() has run (which happens while the kernel is still single
* threaded), the metadata is moved to its final dynamic location, and
* this array is unmapped with the rest of __startup_data at lockdown.
*/
#if CONFIG_GZALLOC
#define ZONE_FOREIGN_META_INLINE_COUNT 20032
#else
#define ZONE_FOREIGN_META_INLINE_COUNT 64
#endif
__startup_data
static struct zone_page_metadata
zone_foreign_meta_array_startup[ZONE_FOREIGN_META_INLINE_COUNT];
/*
* The zone_locks_grp allows for collecting lock statistics.
* All locks are associated to this group in zinit.
* Look at tools/lockstat for debugging lock contention.
*/
static LCK_GRP_DECLARE(zone_locks_grp, "zone_locks");
static LCK_MTX_EARLY_DECLARE(zone_metadata_region_lck, &zone_locks_grp);
/*
* Exclude more than one concurrent garbage collection
*/
static LCK_GRP_DECLARE(zone_gc_lck_grp, "zone_gc");
static LCK_MTX_EARLY_DECLARE(zone_gc_lock, &zone_gc_lck_grp);
bool panic_include_zprint = FALSE;
mach_memory_info_t *panic_kext_memory_info = NULL;
vm_size_t panic_kext_memory_size = 0;
/*
* Protects zone_array, num_zones, num_zones_in_use, and
* zone_destroyed_bitmap
*/
static SIMPLE_LOCK_DECLARE(all_zones_lock, 0);
static zone_id_t num_zones_in_use;
zone_id_t _Atomic num_zones;
SECURITY_READ_ONLY_LATE(unsigned int) zone_view_count;
#if KASAN_ZALLOC
#define MAX_ZONES 566
#else /* !KASAN_ZALLOC */
#define MAX_ZONES 402
#endif/* !KASAN_ZALLOC */
/*
* Initial globals for zone stats until we can allocate the real ones.
* Those get migrated inside the per-CPU ones during zone_init() and
* this array is unmapped with the rest of __startup_data at lockdown.
*/
/* zone to allocate zone_magazine structs from */
static SECURITY_READ_ONLY_LATE(zone_t) zc_magazine_zone;
/*
* Until pid1 is made, zone caching is off,
* until compute_zone_working_set_size() runs for the firt time.
*
* -1 represents the "never enabled yet" value.
*/
static int8_t zone_caching_disabled = -1;
__startup_data
static struct zone_cache zone_cache_startup[MAX_ZONES];
__startup_data
static struct zone_stats zone_stats_startup[MAX_ZONES];
struct zone zone_array[MAX_ZONES];
/* Initialized in zone_bootstrap(), how many "copies" the per-cpu system does */
static SECURITY_READ_ONLY_LATE(unsigned) zpercpu_early_count;
/* Used to keep track of destroyed slots in the zone_array */
static bitmap_t zone_destroyed_bitmap[BITMAP_LEN(MAX_ZONES)];
/* number of zone mapped pages used by all zones */
static long _Atomic zones_phys_page_mapped_count;
/*
* Turn ZSECURITY_OPTIONS_STRICT_IOKIT_FREE off on x86 so as not
* not break third party kexts that haven't yet been recompiled
* to use the new iokit macros.
*/
#if XNU_TARGET_OS_OSX && __x86_64__
#define ZSECURITY_OPTIONS_STRICT_IOKIT_FREE_DEFAULT 0
#else
#define ZSECURITY_OPTIONS_STRICT_IOKIT_FREE_DEFAULT \
ZSECURITY_OPTIONS_STRICT_IOKIT_FREE
#endif
#define ZSECURITY_DEFAULT ( \
ZSECURITY_OPTIONS_SEQUESTER | \
ZSECURITY_OPTIONS_SUBMAP_USER_DATA | \
ZSECURITY_OPTIONS_SEQUESTER_KEXT_KALLOC | \
ZSECURITY_OPTIONS_STRICT_IOKIT_FREE_DEFAULT | \
0)
TUNABLE(zone_security_options_t, zsecurity_options, "zs", ZSECURITY_DEFAULT);
#if VM_MAX_TAG_ZONES
/* enable tags for zones that ask for it */
static TUNABLE(bool, zone_tagging_on, "-zt", false);
#endif /* VM_MAX_TAG_ZONES */
#if DEBUG || DEVELOPMENT
TUNABLE(bool, zalloc_disable_copyio_check, "-no-copyio-zalloc-check", false);
#endif /* DEBUG || DEVELOPMENT */
#if CONFIG_ZLEAKS
/* Making pointer scanning leaks detection possible for all zones */
static TUNABLE(bool, zone_leaks_scan_enable, "-zl", false);
#else
#define zone_leaks_scan_enable false
#endif
/*! @enum zprot_mode_t
*
* @brief
* Zone element corruption detection mode.
*
* @discussion
* We use four techniques to detect modification of a zone element
* after it's been freed.
*
* Elements that are in zones can be in 3 possible states:
* - zeroed out (@c ZPM_ZERO)
* - poisoned (@c ZPM_POISON) with the @c ZONE_POISON pattern
* - with a left and right canary (@c ZPM_CANARY).
*
* @c ZPM_AUTO is used when the actual protection for the element is unknown,
* and will be detected looking at the last word of the allocation at validation
* time.
*
* The mode of an element in zones is discovered by looking at its last
* pointer-sized value:
* - 0 means that it is zeroed out
* - @c ZONE_POISON means it is poisoned
* - any other value means it is using canaries.
*
* Elements are zeroed if:
* - the element size is smaller than @c zp_min_size,
* - the owning zone has the @c z_free_zeroes flag set,
* - the chunk backing store is fresh (and was just allocated).
*
* Elements are poisoned periodically for every N frees (counted per-zone),
* if the elements aren't otherwise zeroed out.
* If -zp is passed as a boot arg, poisoning occurs for every free.
*
* Else elements use canaries. When canaries are used, the first and last
* pointer sized values in the allocation are set to values derived from the
* element address and the @c zp_canary nonce. The first @c zp_min_size
* bytes of the elment are also cleared.
*
* Performance slowdown is inversely proportional to the frequency of poisoning,
* with a 4-5% hit around N=1, down to ~0.3% at N=16 and just "noise" at N=32
* and higher. You can expect to find a 100% reproducible bug in an average of
* N tries, with a standard deviation of about N, but you will want to set
* "-zp" to always poison every free if you are attempting to reproduce
* a known bug.
*
* For a more heavyweight, but finer-grained method of detecting misuse
* of zone memory, look up the "Guard mode" zone allocator in gzalloc.c.
*/
__enum_closed_decl(zprot_mode_t, vm_offset_t, {
ZPM_AUTO, /* element is indeterminate */
ZPM_ZERO, /* element is zeroed */
ZPM_POISON, /* element is poisoned */
ZPM_CANARY, /* element extremities have a canary */
});
#define ZPM_MASK ((zprot_mode_t)0x3)
/*
* set by zp-factor=N boot arg
*
* A zp_factor of 0 indicates zone poisoning is disabled and can also be set by
* passing the -no-zp boot-arg.
*
* A zp_factor of 1 indicates zone poisoning is on for all elements and can be
* set by passing the -zp boot-arg.
*/
static TUNABLE(uint32_t, zp_factor, "zp-factor", 16);
/* set by zp-scale=N boot arg, scales zp_factor by zone size */
static TUNABLE(uint32_t, zp_scale, "zp-scale", 4);
/*
* Zone caching tunables
*
* zc_mag_size():
* size of magazines, larger to reduce contention at the expense of memory
*
* zc_auto_enable_threshold
* number of contentions per second after which zone caching engages
* automatically.
*
* 0 to disable.
*
* zc_grow_threshold
* numer of contentions per second after which the per-cpu depot layer
* grows at each newly observed contention without restriction.
*
* 0 to disable.
*
* zc_recirc_denom
* denominator of the fraction of per-cpu depot to migrate to/from
* the recirculation depot layer at a time. Default 3 (1/3).
*
* zc_defrag_ratio
* percentage of the working set to recirc size below which
* the zone is defragmented. Default is 50%.
*
* zc_free_batch_size
* The size of batches of frees/reclaim that can be done keeping
* the zone lock held (and preemption disabled).
*/
static TUNABLE(uint16_t, zc_magazine_size, "zc_mag_size()", 8);
static TUNABLE(uint32_t, zc_auto_threshold, "zc_auto_enable_threshold", 20);
static TUNABLE(uint32_t, zc_grow_threshold, "zc_grow_threshold", 8);
static TUNABLE(uint32_t, zc_recirc_denom, "zc_recirc_denom", 3);
static TUNABLE(uint32_t, zc_defrag_ratio, "zc_defrag_ratio", 50);
static TUNABLE(uint32_t, zc_free_batch_size, "zc_free_batch_size", 1024);
static SECURITY_READ_ONLY_LATE(uintptr_t) zp_canary;
/*
* Perf results for zeroing all non data zones and 2K of data zones
* showed little regression, therefore setting zp_min_size to 2048
*/
static TUNABLE(uint32_t, zp_min_size, "zclear_size", 2048);
static SECURITY_READ_ONLY_LATE(uint32_t) zone_phys_mapped_max_pages;
static SECURITY_READ_ONLY_LATE(vm_map_t) zone_submaps[Z_SUBMAP_IDX_COUNT];
static SECURITY_READ_ONLY_LATE(uint32_t) zone_last_submap_idx;
static zone_t zone_find_largest(void);
#endif /* !ZALLOC_TEST */
#pragma mark Zone metadata
#if !ZALLOC_TEST
static inline zone_id_t
zone_index(zone_t z)
{
return (zone_id_t)(z - zone_array);
}
static inline bool
zone_has_index(zone_t z, zone_id_t zid)
{
return zone_array + zid == z;
}
static zone_element_t
zone_element_encode(vm_offset_t base, vm_offset_t eidx, zprot_mode_t zpm)
{
return (zone_element_t){ .ze_value = base | (eidx << 2) | zpm };
}
static vm_offset_t
zone_element_base(zone_element_t ze)
{
return trunc_page(ze.ze_value);
}
static vm_offset_t
zone_element_idx(zone_element_t ze)
{
return (ze.ze_value & PAGE_MASK) >> 2;
}
#if ZALLOC_ENABLE_POISONING
static zprot_mode_t
zone_element_prot(zone_element_t ze)
{
return (zprot_mode_t)(ze.ze_value & ZPM_MASK);
}
#endif
static vm_offset_t
zone_element_addr(zone_element_t ze, vm_offset_t esize)
{
return zone_element_base(ze) + esize * zone_element_idx(ze);
}
__abortlike
static void
zone_metadata_corruption(zone_t zone, struct zone_page_metadata *meta,
const char *kind)
{
panic("zone metadata corruption: %s (meta %p, zone %s%s)",
kind, meta, zone_heap_name(zone), zone->z_name);
}
__abortlike
static void
zone_invalid_element_addr_panic(zone_t zone, vm_offset_t addr)
{
panic("zone element pointer validation failed (addr: %p, zone %s%s)",
(void *)addr, zone_heap_name(zone), zone->z_name);
}
__abortlike
static void
zone_invalid_element_panic(zone_t zone, zone_element_t ze)
{
panic("zone element pointer validation failed (elem: %p,%d, zone %s%s)",
(void *)zone_element_base(ze), (int)zone_element_idx(ze),
zone_heap_name(zone), zone->z_name);
}
__abortlike
static void
zone_page_metadata_index_confusion_panic(zone_t zone, vm_offset_t addr,
struct zone_page_metadata *meta)
{
panic("%p not in the expected zone %s%s (%d != %d)",
(void *)addr, zone_heap_name(zone), zone->z_name,
meta->zm_index, zone_index(zone));
}
__abortlike
static void
zone_page_metadata_native_queue_corruption(zone_t zone, zone_pva_t *queue)
{
panic("foreign metadata index %d enqueued in native head %p from zone %s%s",
queue->packed_address, queue, zone_heap_name(zone),
zone->z_name);
}
__abortlike
static void
zone_page_metadata_list_corruption(zone_t zone, struct zone_page_metadata *meta)
{
panic("metadata list corruption through element %p detected in zone %s%s",
meta, zone_heap_name(zone), zone->z_name);
}
__abortlike __unused
static void
zone_invalid_foreign_addr_panic(zone_t zone, vm_offset_t addr)
{
panic("addr %p being freed to foreign zone %s%s not from foreign range",
(void *)addr, zone_heap_name(zone), zone->z_name);
}
__abortlike
static void
zone_page_meta_accounting_panic(zone_t zone, struct zone_page_metadata *meta,
const char *kind)
{
panic("accounting mismatch (%s) for zone %s%s, meta %p", kind,
zone_heap_name(zone), zone->z_name, meta);
}
__abortlike
static void
zone_meta_double_free_panic(zone_t zone, zone_element_t ze, const char *caller)
{
panic("%s: double free of %p to zone %s%s", caller,
(void *)zone_element_addr(ze, zone_elem_size(zone)),
zone_heap_name(zone), zone->z_name);
}
__abortlike
static void
zone_accounting_panic(zone_t zone, const char *kind)
{
panic("accounting mismatch (%s) for zone %s%s", kind,
zone_heap_name(zone), zone->z_name);
}
#define zone_counter_sub(z, stat, value) ({ \
if (os_sub_overflow((z)->stat, value, &(z)->stat)) { \
zone_accounting_panic(z, #stat " wrap-around"); \
} \
(z)->stat; \
})
static inline void
zone_elems_free_add(zone_t z, uint32_t count)
{
uint32_t n = (z->z_elems_free += count);
if (z->z_elems_free_max < n) {
z->z_elems_free_max = n;
}
}
static inline void
zone_elems_free_sub(zone_t z, uint32_t count)
{
uint32_t n = zone_counter_sub(z, z_elems_free, count);
if (z->z_elems_free_min > n) {
z->z_elems_free_min = n;
}
}
static inline uint16_t
zone_meta_alloc_size_add(zone_t z, struct zone_page_metadata *m,
vm_offset_t esize)
{
if (os_add_overflow(m->zm_alloc_size, (uint16_t)esize, &m->zm_alloc_size)) {
zone_page_meta_accounting_panic(z, m, "alloc_size wrap-around");
}
return m->zm_alloc_size;
}
static inline uint16_t
zone_meta_alloc_size_sub(zone_t z, struct zone_page_metadata *m,
vm_offset_t esize)
{
if (os_sub_overflow(m->zm_alloc_size, esize, &m->zm_alloc_size)) {
zone_page_meta_accounting_panic(z, m, "alloc_size wrap-around");
}
return m->zm_alloc_size;
}
__abortlike
static void
zone_nofail_panic(zone_t zone)
{
panic("zalloc(Z_NOFAIL) can't be satisfied for zone %s%s (potential leak)",
zone_heap_name(zone), zone->z_name);
}
#if __arm64__
// <rdar://problem/48304934> arm64 doesn't use ldp when I'd expect it to
#define zone_range_load(r, rmin, rmax) \
asm("ldp %[rmin], %[rmax], [%[range]]" \
: [rmin] "=r"(rmin), [rmax] "=r"(rmax) \
: [range] "r"(r))
#else
#define zone_range_load(r, rmin, rmax) \
({ rmin = (r)->min_address; rmax = (r)->max_address; })
#endif
__header_always_inline bool
zone_range_contains(const struct zone_map_range *r, vm_offset_t addr, vm_offset_t size)
{
vm_offset_t rmin, rmax;
/*
* The `&` is not a typo: we really expect the check to pass,
* so encourage the compiler to eagerly load and test without branches
*/
zone_range_load(r, rmin, rmax);
return (addr >= rmin) & (addr + size >= rmin) & (addr + size <= rmax);
}
__header_always_inline vm_size_t
zone_range_size(const struct zone_map_range *r)
{
vm_offset_t rmin, rmax;
zone_range_load(r, rmin, rmax);
return rmax - rmin;
}
#define from_zone_map(addr, size, kind) \
zone_range_contains(&zone_info.zi_map_range[kind], \
(vm_offset_t)(addr), size)
#define zone_native_size() \
zone_range_size(&zone_info.zi_map_range[ZONE_ADDR_NATIVE])
#define zone_foreign_size() \
zone_range_size(&zone_info.zi_map_range[ZONE_ADDR_FOREIGN])
__header_always_inline bool
zone_pva_is_null(zone_pva_t page)
{
return page.packed_address == 0;
}
__header_always_inline bool
zone_pva_is_queue(zone_pva_t page)
{
// actual kernel pages have the top bit set
return (int32_t)page.packed_address > 0;
}
__header_always_inline bool
zone_pva_is_equal(zone_pva_t pva1, zone_pva_t pva2)
{
return pva1.packed_address == pva2.packed_address;
}
__header_always_inline void
zone_queue_set_head(zone_t z, zone_pva_t queue, zone_pva_t oldv,
struct zone_page_metadata *meta)
{
zone_pva_t *queue_head = &((zone_pva_t *)zone_array)[queue.packed_address];
if (!zone_pva_is_equal(*queue_head, oldv)) {
zone_page_metadata_list_corruption(z, meta);
}
*queue_head = meta->zm_page_next;
}
__header_always_inline zone_pva_t
zone_queue_encode(zone_pva_t *headp)
{
return (zone_pva_t){ (uint32_t)(headp - (zone_pva_t *)zone_array) };
}
__header_always_inline zone_pva_t
zone_pva_from_addr(vm_address_t addr)
{
// cannot use atop() because we want to maintain the sign bit
return (zone_pva_t){ (uint32_t)((intptr_t)addr >> PAGE_SHIFT) };
}
__header_always_inline zone_pva_t
zone_pva_from_element(zone_element_t ze)
{
return zone_pva_from_addr(ze.ze_value);
}
__header_always_inline vm_address_t
zone_pva_to_addr(zone_pva_t page)
{
// cause sign extension so that we end up with the right address
return (vm_offset_t)(int32_t)page.packed_address << PAGE_SHIFT;
}
__header_always_inline struct zone_page_metadata *
zone_pva_to_meta(zone_pva_t page)
{
return &zone_info.zi_meta_base[page.packed_address];
}
__header_always_inline zone_pva_t
zone_pva_from_meta(struct zone_page_metadata *meta)
{
return (zone_pva_t){ (uint32_t)(meta - zone_info.zi_meta_base) };
}
__header_always_inline struct zone_page_metadata *
zone_meta_from_addr(vm_offset_t addr)
{
return zone_pva_to_meta(zone_pva_from_addr(addr));
}
__header_always_inline struct zone_page_metadata *
zone_meta_from_element(zone_element_t ze)
{
return zone_pva_to_meta(zone_pva_from_element(ze));
}
__header_always_inline zone_id_t
zone_index_from_ptr(const void *ptr)
{
return zone_pva_to_meta(zone_pva_from_addr((vm_offset_t)ptr))->zm_index;
}
__header_always_inline vm_offset_t
zone_meta_to_addr(struct zone_page_metadata *meta)
{
return ptoa((int32_t)(meta - zone_info.zi_meta_base));
}
__header_always_inline void
zone_meta_queue_push(zone_t z, zone_pva_t *headp,
struct zone_page_metadata *meta)
{
zone_pva_t head = *headp;
zone_pva_t queue_pva = zone_queue_encode(headp);
struct zone_page_metadata *tmp;
meta->zm_page_next = head;
if (!zone_pva_is_null(head)) {
tmp = zone_pva_to_meta(head);
if (!zone_pva_is_equal(tmp->zm_page_prev, queue_pva)) {
zone_page_metadata_list_corruption(z, meta);
}
tmp->zm_page_prev = zone_pva_from_meta(meta);
}
meta->zm_page_prev = queue_pva;
*headp = zone_pva_from_meta(meta);
}
__header_always_inline struct zone_page_metadata *
zone_meta_queue_pop_native(zone_t z, zone_pva_t *headp, vm_offset_t *page_addrp)
{
zone_pva_t head = *headp;
struct zone_page_metadata *meta = zone_pva_to_meta(head);
vm_offset_t page_addr = zone_pva_to_addr(head);
struct zone_page_metadata *tmp;
if (!from_zone_map(page_addr, 1, ZONE_ADDR_NATIVE)) {
zone_page_metadata_native_queue_corruption(z, headp);
}
if (!zone_pva_is_null(meta->zm_page_next)) {
tmp = zone_pva_to_meta(meta->zm_page_next);
if (!zone_pva_is_equal(tmp->zm_page_prev, head)) {
zone_page_metadata_list_corruption(z, meta);
}
tmp->zm_page_prev = meta->zm_page_prev;
}
*headp = meta->zm_page_next;
meta->zm_page_next = meta->zm_page_prev = (zone_pva_t){ 0 };
*page_addrp = page_addr;
if (!zone_has_index(z, meta->zm_index)) {
zone_page_metadata_index_confusion_panic(z,
zone_meta_to_addr(meta), meta);
}
return meta;
}
__header_always_inline void
zone_meta_remqueue(zone_t z, struct zone_page_metadata *meta)
{
zone_pva_t meta_pva = zone_pva_from_meta(meta);
struct zone_page_metadata *tmp;
if (!zone_pva_is_null(meta->zm_page_next)) {
tmp = zone_pva_to_meta(meta->zm_page_next);
if (!zone_pva_is_equal(tmp->zm_page_prev, meta_pva)) {
zone_page_metadata_list_corruption(z, meta);
}
tmp->zm_page_prev = meta->zm_page_prev;
}
if (zone_pva_is_queue(meta->zm_page_prev)) {
zone_queue_set_head(z, meta->zm_page_prev, meta_pva, meta);
} else {
tmp = zone_pva_to_meta(meta->zm_page_prev);
if (!zone_pva_is_equal(tmp->zm_page_next, meta_pva)) {
zone_page_metadata_list_corruption(z, meta);
}
tmp->zm_page_next = meta->zm_page_next;
}
meta->zm_page_next = meta->zm_page_prev = (zone_pva_t){ 0 };
}
__header_always_inline void
zone_meta_requeue(zone_t z, zone_pva_t *headp,
struct zone_page_metadata *meta)
{
zone_meta_remqueue(z, meta);
zone_meta_queue_push(z, headp, meta);
}
/* prevents a given metadata from ever reaching the z_pageq_empty queue */
static inline void
zone_meta_lock_in_partial(zone_t z, struct zone_page_metadata *m, uint32_t len)
{
uint16_t new_size = zone_meta_alloc_size_add(z, m, ZM_ALLOC_SIZE_LOCK);
assert(new_size % sizeof(vm_offset_t) == ZM_ALLOC_SIZE_LOCK);
if (new_size == ZM_ALLOC_SIZE_LOCK) {
zone_meta_requeue(z, &z->z_pageq_partial, m);
zone_counter_sub(z, z_wired_empty, len);
}
}
/* allows a given metadata to reach the z_pageq_empty queue again */
static inline void
zone_meta_unlock_from_partial(zone_t z, struct zone_page_metadata *m, uint32_t len)
{
uint16_t new_size = zone_meta_alloc_size_sub(z, m, ZM_ALLOC_SIZE_LOCK);
assert(new_size % sizeof(vm_offset_t) == 0);
if (new_size == 0) {
zone_meta_requeue(z, &z->z_pageq_empty, m);
z->z_wired_empty += len;
}
}
/*
* Routine to populate a page backing metadata in the zone_metadata_region.
* Must be called without the zone lock held as it might potentially block.
*/
static void
zone_meta_populate(vm_offset_t base, vm_size_t size)
{
struct zone_page_metadata *from = zone_meta_from_addr(base);
struct zone_page_metadata *to = from + atop(size);
vm_offset_t page_addr = trunc_page(from);
for (; page_addr < (vm_offset_t)to; page_addr += PAGE_SIZE) {
#if !KASAN_ZALLOC
/*
* This can race with another thread doing a populate on the same metadata
* page, where we see an updated pmap but unmapped KASan shadow, causing a
* fault in the shadow when we first access the metadata page. Avoid this
* by always synchronizing on the zone_metadata_region lock with KASan.
*/
if (pmap_find_phys(kernel_pmap, page_addr)) {
continue;
}
#endif
for (;;) {
kern_return_t ret = KERN_SUCCESS;
/* All updates to the zone_metadata_region are done under the zone_metadata_region_lck */
lck_mtx_lock(&zone_metadata_region_lck);
if (0 == pmap_find_phys(kernel_pmap, page_addr)) {
ret = kernel_memory_populate(kernel_map, page_addr,
PAGE_SIZE, KMA_NOPAGEWAIT | KMA_KOBJECT | KMA_ZERO,
VM_KERN_MEMORY_OSFMK);
}
lck_mtx_unlock(&zone_metadata_region_lck);
if (ret == KERN_SUCCESS) {
break;
}
/*
* We can't pass KMA_NOPAGEWAIT under a global lock as it leads
* to bad system deadlocks, so if the allocation failed,
* we need to do the VM_PAGE_WAIT() outside of the lock.
*/
VM_PAGE_WAIT();
}
}
}
__header_always_inline
struct zone_page_metadata *
zone_element_validate(zone_t zone, zone_element_t ze)
{
struct zone_page_metadata *meta;
vm_offset_t page = zone_element_base(ze);
if (!from_zone_map(page, 1, ZONE_ADDR_NATIVE) &&
!from_zone_map(page, 1, ZONE_ADDR_FOREIGN)) {
zone_invalid_element_panic(zone, ze);
}
meta = zone_meta_from_addr(page);
if (meta->zm_chunk_len > ZM_CHUNK_LEN_MAX) {
zone_invalid_element_panic(zone, ze);
}
if (zone_element_idx(ze) >= zone->z_chunk_elems) {
zone_invalid_element_panic(zone, ze);
}
if (!zone_has_index(zone, meta->zm_index)) {
vm_offset_t addr = zone_element_addr(ze, zone_elem_size(zone));
zone_page_metadata_index_confusion_panic(zone, addr, meta);
}
return meta;
}
__attribute__((always_inline))
static struct zone_page_metadata *
zone_element_resolve(zone_t zone, vm_offset_t addr, vm_offset_t esize,
zone_element_t *ze)
{
struct zone_page_metadata *meta;
vm_offset_t page, eidx;
if (!from_zone_map(addr, esize, ZONE_ADDR_NATIVE) &&
!from_zone_map(addr, esize, ZONE_ADDR_FOREIGN)) {
zone_invalid_element_addr_panic(zone, addr);
}
page = trunc_page(addr);
meta = zone_meta_from_addr(addr);
if (meta->zm_chunk_len == ZM_SECONDARY_PCPU_PAGE) {
zone_invalid_element_addr_panic(zone, addr);
}
if (meta->zm_chunk_len == ZM_SECONDARY_PAGE) {
page -= ptoa(meta->zm_page_index);
meta -= meta->zm_page_index;
}
eidx = (addr - page) / esize;
if ((addr - page) % esize) {
zone_invalid_element_addr_panic(zone, addr);
}
if (!zone_has_index(zone, meta->zm_index)) {
zone_page_metadata_index_confusion_panic(zone, addr, meta);
}
*ze = zone_element_encode(page, eidx, ZPM_AUTO);
return meta;
}
/* Routine to get the size of a zone allocated address.
* If the address doesnt belong to the zone maps, returns 0.
*/
vm_size_t
zone_element_size(void *addr, zone_t *z)
{
struct zone *src_zone;
if (from_zone_map(addr, sizeof(void *), ZONE_ADDR_NATIVE) ||
from_zone_map(addr, sizeof(void *), ZONE_ADDR_FOREIGN)) {
src_zone = &zone_array[zone_index_from_ptr(addr)];
if (z) {
*z = src_zone;
}
return zone_elem_size(src_zone);
}
#if CONFIG_GZALLOC
if (__improbable(gzalloc_enabled())) {
vm_size_t gzsize;
if (gzalloc_element_size(addr, z, &gzsize)) {
return gzsize;
}
}
#endif /* CONFIG_GZALLOC */
return 0;
}
/* This function just formats the reason for the panics by redoing the checks */
__abortlike
static void
zone_require_panic(zone_t zone, void *addr)
{
uint32_t zindex;
zone_t other;
if (!from_zone_map(addr, zone_elem_size(zone), ZONE_ADDR_NATIVE)) {
panic("zone_require failed: address not in a zone (addr: %p)", addr);
}
zindex = zone_index_from_ptr(addr);
other = &zone_array[zindex];
if (zindex >= os_atomic_load(&num_zones, relaxed) || !other->z_self) {
panic("zone_require failed: invalid zone index %d "
"(addr: %p, expected: %s%s)", zindex,
addr, zone_heap_name(zone), zone->z_name);
} else {
panic("zone_require failed: address in unexpected zone id %d (%s%s) "
"(addr: %p, expected: %s%s)",
zindex, zone_heap_name(other), other->z_name,
addr, zone_heap_name(zone), zone->z_name);
}
}
__abortlike
static void
zone_id_require_panic(zone_id_t zid, void *addr)
{
zone_require_panic(&zone_array[zid], addr);
}
/*
* Routines to panic if a pointer is not mapped to an expected zone.
* This can be used as a means of pinning an object to the zone it is expected
* to be a part of. Causes a panic if the address does not belong to any
* specified zone, does not belong to any zone, has been freed and therefore
* unmapped from the zone, or the pointer contains an uninitialized value that
* does not belong to any zone.
*
* Note that this can only work with collectable zones without foreign pages.
*/
void
zone_require(zone_t zone, void *addr)
{
vm_size_t esize = zone_elem_size(zone);
if (__probable(from_zone_map(addr, esize, ZONE_ADDR_NATIVE))) {
if (zone_has_index(zone, zone_index_from_ptr(addr))) {
return;
}
#if CONFIG_GZALLOC
} else if (__probable(zone->gzalloc_tracked)) {
return;
#endif
}
zone_require_panic(zone, addr);
}
void
zone_id_require(zone_id_t zid, vm_size_t esize, void *addr)
{
if (__probable(from_zone_map(addr, esize, ZONE_ADDR_NATIVE))) {
if (zid == zone_index_from_ptr(addr)) {
return;
}
#if CONFIG_GZALLOC
} else if (__probable(zone_array[zid].gzalloc_tracked)) {
return;
#endif
}
zone_id_require_panic(zid, addr);
}
void
zone_id_require_allow_foreign(zone_id_t zid, vm_size_t esize, void *addr)
{
if (__probable(from_zone_map(addr, esize, ZONE_ADDR_NATIVE) ||
from_zone_map(addr, esize, ZONE_ADDR_FOREIGN))) {
if (zid == zone_index_from_ptr(addr)) {
return;
}
#if CONFIG_GZALLOC
} else if (__probable(zone_array[zid].gzalloc_tracked)) {
return;
#endif
}
zone_id_require_panic(zid, addr);
}
bool
zone_owns(zone_t zone, void *addr)
{
vm_size_t esize = zone_elem_size(zone);
if (__probable(from_zone_map(addr, esize, ZONE_ADDR_NATIVE))) {
return zone_has_index(zone, zone_index_from_ptr(addr));
#if CONFIG_GZALLOC
} else if (__probable(zone->gzalloc_tracked)) {
return true;
#endif
}
return false;
}
#endif /* !ZALLOC_TEST */
#pragma mark Zone bits allocator
/*!
* @defgroup Zone Bitmap allocator
* @{
*
* @brief
* Functions implementing the zone bitmap allocator
*
* @discussion
* The zone allocator maintains which elements are allocated or free in bitmaps.
*
* When the number of elements per page is smaller than 32, it is stored inline
* on the @c zone_page_metadata structure (@c zm_inline_bitmap is set,
* and @c zm_bitmap used for storage).
*
* When the number of elements is larger, then a bitmap is allocated from
* a buddy allocator (impelemented under the @c zba_* namespace). Pointers
* to bitmaps are implemented as a packed 32 bit bitmap reference, stored in
* @c zm_bitmap. The low 3 bits encode the scale (order) of the allocation in
* @c ZBA_GRANULE units, and hence actual allocations encoded with that scheme
* cannot be larger than 1024 bytes (8192 bits).
*
* This buddy allocator can actually accomodate allocations as large
* as 8k on 16k systems and 2k on 4k systems.
*
* Note: @c zba_* functions are implementation details not meant to be used
* outside of the allocation of the allocator itself. Interfaces to the rest of
* the zone allocator are documented and not @c zba_* prefixed.
*/
#define ZBA_CHUNK_SIZE PAGE_MAX_SIZE
#define ZBA_GRANULE sizeof(uint64_t)
#define ZBA_GRANULE_BITS (8 * sizeof(uint64_t))
#define ZBA_MAX_ORDER (PAGE_MAX_SHIFT - 4)
#define ZBA_MAX_ALLOC_ORDER 7
#define ZBA_SLOTS (ZBA_CHUNK_SIZE / ZBA_GRANULE)
static_assert(2ul * ZBA_GRANULE << ZBA_MAX_ORDER == ZBA_CHUNK_SIZE, "chunk sizes");
static_assert(ZBA_MAX_ALLOC_ORDER <= ZBA_MAX_ORDER, "ZBA_MAX_ORDER is enough");
struct zone_bits_chain {
uint32_t zbc_next;
uint32_t zbc_prev;
} __attribute__((aligned(ZBA_GRANULE)));
struct zone_bits_head {
uint32_t zbh_next;
uint32_t zbh_unused;
} __attribute__((aligned(ZBA_GRANULE)));
static_assert(sizeof(struct zone_bits_chain) == ZBA_GRANULE, "zbc size");
static_assert(sizeof(struct zone_bits_head) == ZBA_GRANULE, "zbh size");
struct zone_bits_allocator_meta {
uint32_t zbam_chunks;
uint32_t __zbam_padding;
struct zone_bits_head zbam_lists[ZBA_MAX_ORDER + 1];
};
struct zone_bits_allocator_header {
uint64_t zbah_bits[ZBA_SLOTS / (8 * sizeof(uint64_t))];
};
#if ZALLOC_TEST
static struct zalloc_bits_allocator_test_setup {
vm_offset_t zbats_base;
void (*zbats_populate)(vm_address_t addr, vm_size_t size);
} zba_test_info;
static struct zone_bits_allocator_header *
zba_base_header(void)
{
return (struct zone_bits_allocator_header *)zba_test_info.zbats_base;
}
static void
zba_populate(uint32_t n)
{
vm_address_t base = zba_test_info.zbats_base;
zba_test_info.zbats_populate(base + n * ZBA_CHUNK_SIZE, ZBA_CHUNK_SIZE);
}
#else
__startup_data
static uint8_t zba_chunk_startup[ZBA_CHUNK_SIZE]
__attribute__((aligned(ZBA_CHUNK_SIZE)));
static LCK_MTX_EARLY_DECLARE(zba_mtx, &zone_locks_grp);
static struct zone_bits_allocator_header *
zba_base_header(void)
{
return (struct zone_bits_allocator_header *)zone_info.zi_bits_range.min_address;
}
static void
zba_lock(void)
{
lck_mtx_lock(&zba_mtx);
}
static void
zba_unlock(void)
{
lck_mtx_unlock(&zba_mtx);
}
static void
zba_populate(uint32_t n)
{
vm_size_t size = ZBA_CHUNK_SIZE;
vm_address_t addr;
addr = zone_info.zi_bits_range.min_address + n * size;
if (addr >= zone_info.zi_bits_range.max_address) {
zone_t z = zone_find_largest();
panic("zba_populate: out of bitmap space, "
"likely due to memory leak in zone [%s%s] "
"(%luM, %d elements allocated)",
zone_heap_name(z), zone_name(z),
(unsigned long)zone_size_wired(z) >> 20,
zone_count_allocated(z));
}
for (;;) {
kern_return_t kr = KERN_SUCCESS;
if (0 == pmap_find_phys(kernel_pmap, addr)) {
kr = kernel_memory_populate(kernel_map, addr, size,
KMA_NOPAGEWAIT | KMA_KOBJECT | KMA_ZERO,
VM_KERN_MEMORY_OSFMK);
}
if (kr == KERN_SUCCESS) {
return;
}
zba_unlock();
VM_PAGE_WAIT();
zba_lock();
}
}
#endif
__pure2
static struct zone_bits_allocator_meta *
zba_meta(void)
{
return (struct zone_bits_allocator_meta *)&zba_base_header()[1];
}
__pure2
static uint64_t *
zba_slot_base(void)
{
return (uint64_t *)zba_base_header();
}
__pure2
static vm_address_t
zba_page_addr(uint32_t n)
{
return (vm_address_t)zba_base_header() + n * ZBA_CHUNK_SIZE;
}
__pure2
static struct zone_bits_head *
zba_head(uint32_t order)
{
return &zba_meta()->zbam_lists[order];
}
__pure2
static uint32_t
zba_head_index(uint32_t order)
{
uint32_t hdr_size = sizeof(struct zone_bits_allocator_header) +
offsetof(struct zone_bits_allocator_meta, zbam_lists);
return (hdr_size / ZBA_GRANULE) + order;
}
__pure2
static struct zone_bits_chain *
zba_chain_for_index(uint32_t index)
{
return (struct zone_bits_chain *)(zba_slot_base() + index);
}
__pure2
static uint32_t
zba_chain_to_index(const struct zone_bits_chain *zbc)
{
return (uint32_t)((const uint64_t *)zbc - zba_slot_base());
}
__abortlike
static void
zba_head_corruption_panic(uint32_t order)
{
panic("zone bits allocator head[%d:%p] is corrupt", order,
zba_head(order));
}
__abortlike
static void
zba_chain_corruption_panic(struct zone_bits_chain *a, struct zone_bits_chain *b)
{
panic("zone bits allocator freelist is corrupt (%p <-> %p)", a, b);
}
static void
zba_push_block(struct zone_bits_chain *zbc, uint32_t order)
{
struct zone_bits_head *hd = zba_head(order);
uint32_t hd_index = zba_head_index(order);
uint32_t index = zba_chain_to_index(zbc);
struct zone_bits_chain *next;
if (hd->zbh_next) {
next = zba_chain_for_index(hd->zbh_next);
if (next->zbc_prev != hd_index) {
zba_head_corruption_panic(order);
}
next->zbc_prev = index;
}
zbc->zbc_next = hd->zbh_next;
zbc->zbc_prev = hd_index;
hd->zbh_next = index;
}
static void
zba_remove_block(struct zone_bits_chain *zbc)
{
struct zone_bits_chain *prev = zba_chain_for_index(zbc->zbc_prev);
uint32_t index = zba_chain_to_index(zbc);
if (prev->zbc_next != index) {
zba_chain_corruption_panic(prev, zbc);
}
if ((prev->zbc_next = zbc->zbc_next)) {
struct zone_bits_chain *next = zba_chain_for_index(zbc->zbc_next);
if (next->zbc_prev != index) {
zba_chain_corruption_panic(zbc, next);
}
next->zbc_prev = zbc->zbc_prev;
}
}
static vm_address_t
zba_try_pop_block(uint32_t order)
{
struct zone_bits_head *hd = zba_head(order);
struct zone_bits_chain *zbc;
if (hd->zbh_next == 0) {
return 0;
}
zbc = zba_chain_for_index(hd->zbh_next);
zba_remove_block(zbc);
return (vm_address_t)zbc;
}
static struct zone_bits_allocator_header *
zba_header(vm_offset_t addr)
{
addr &= -(vm_offset_t)ZBA_CHUNK_SIZE;
return (struct zone_bits_allocator_header *)addr;
}
static size_t
zba_node_parent(size_t node)
{
return (node - 1) / 2;
}
static size_t
zba_node_left_child(size_t node)
{
return node * 2 + 1;
}
static size_t
zba_node_buddy(size_t node)
{
return ((node - 1) ^ 1) + 1;
}
static size_t
zba_node(vm_offset_t addr, uint32_t order)
{
vm_offset_t offs = (addr % ZBA_CHUNK_SIZE) / ZBA_GRANULE;
return (offs >> order) + (1 << (ZBA_MAX_ORDER - order + 1)) - 1;
}
static struct zone_bits_chain *
zba_chain_for_node(struct zone_bits_allocator_header *zbah, size_t node, uint32_t order)
{
vm_offset_t offs = (node - (1 << (ZBA_MAX_ORDER - order + 1)) + 1) << order;
return (struct zone_bits_chain *)((vm_offset_t)zbah + offs * ZBA_GRANULE);
}
static void
zba_node_flip_split(struct zone_bits_allocator_header *zbah, size_t node)
{
zbah->zbah_bits[node / 64] ^= 1ull << (node % 64);
}
static bool
zba_node_is_split(struct zone_bits_allocator_header *zbah, size_t node)
{
return zbah->zbah_bits[node / 64] & (1ull << (node % 64));
}
static void
zba_free(vm_offset_t addr, uint32_t order)
{
struct zone_bits_allocator_header *zbah = zba_header(addr);
struct zone_bits_chain *zbc;
size_t node = zba_node(addr, order);
while (node) {
size_t parent = zba_node_parent(node);
zba_node_flip_split(zbah, parent);
if (zba_node_is_split(zbah, parent)) {
break;
}
zbc = zba_chain_for_node(zbah, zba_node_buddy(node), order);
zba_remove_block(zbc);
order++;
node = parent;
}
zba_push_block(zba_chain_for_node(zbah, node, order), order);
}
static vm_size_t
zba_chunk_header_size(uint32_t n)
{
vm_size_t hdr_size = sizeof(struct zone_bits_allocator_header);
if (n == 0) {
hdr_size += sizeof(struct zone_bits_allocator_meta);
}
return hdr_size;
}
static void
zba_init_chunk(uint32_t n)
{
vm_size_t hdr_size = zba_chunk_header_size(n);
vm_offset_t page = zba_page_addr(n);
struct zone_bits_allocator_header *zbah = zba_header(page);
vm_size_t size = ZBA_CHUNK_SIZE;
size_t node;
for (uint32_t o = ZBA_MAX_ORDER + 1; o-- > 0;) {
if (size < hdr_size + (ZBA_GRANULE << o)) {
continue;
}
size -= ZBA_GRANULE << o;
node = zba_node(page + size, o);
zba_node_flip_split(zbah, zba_node_parent(node));
zba_push_block(zba_chain_for_node(zbah, node, o), o);
}
zba_meta()->zbam_chunks = n + 1;
}
__attribute__((noinline))
static void
zba_grow(void)
{
uint32_t chunk = zba_meta()->zbam_chunks;
zba_populate(chunk);
if (zba_meta()->zbam_chunks == chunk) {
zba_init_chunk(chunk);
}
}
static vm_offset_t
zba_alloc(uint32_t order)
{
struct zone_bits_allocator_header *zbah;
uint32_t cur = order;
vm_address_t addr;
size_t node;
while ((addr = zba_try_pop_block(cur)) == 0) {
if (cur++ >= ZBA_MAX_ORDER) {
zba_grow();
cur = order;
}
}
zbah = zba_header(addr);
node = zba_node(addr, cur);
zba_node_flip_split(zbah, zba_node_parent(node));
while (cur > order) {
cur--;
zba_node_flip_split(zbah, node);
node = zba_node_left_child(node);
zba_push_block(zba_chain_for_node(zbah, node + 1, cur), cur);
}
return addr;
}
#define zba_map_index(type, n) (n / (8 * sizeof(type)))
#define zba_map_bit(type, n) ((type)1 << (n % (8 * sizeof(type))))
#define zba_map_mask_lt(type, n) (zba_map_bit(type, n) - 1)
#define zba_map_mask_ge(type, n) ((type)-zba_map_bit(type, n))
#if !ZALLOC_TEST
static uint32_t
zba_bits_ref_order(uint32_t bref)
{
return bref & 0x7;
}
static bitmap_t *
zba_bits_ref_ptr(uint32_t bref)
{
return zba_slot_base() + (bref >> 3);
}
static vm_offset_t
zba_scan_bitmap_inline(zone_t zone, struct zone_page_metadata *meta,
vm_offset_t eidx)
{
size_t i = eidx / 32;
uint32_t map;
if (eidx % 32) {
map = meta[i].zm_bitmap & zba_map_mask_ge(uint32_t, eidx);
if (map) {
eidx = __builtin_ctz(map);
meta[i].zm_bitmap ^= 1u << eidx;
return i * 32 + eidx;
}
i++;
}
uint32_t chunk_len = meta->zm_chunk_len;
if (chunk_len == 1 && zone->z_percpu) {
chunk_len = zpercpu_count();
}
for (int j = 0; j < chunk_len; j++, i++) {
if (i >= chunk_len) {
i = 0;
}
if (__probable(map = meta[i].zm_bitmap)) {
meta[i].zm_bitmap &= map - 1;
return i * 32 + __builtin_ctz(map);
}
}
zone_page_meta_accounting_panic(zone, meta, "zm_bitmap");
}
static vm_offset_t
zba_scan_bitmap_ref(zone_t zone, struct zone_page_metadata *meta,
vm_offset_t eidx)
{
uint32_t bits_size = 1 << zba_bits_ref_order(meta->zm_bitmap);
bitmap_t *bits = zba_bits_ref_ptr(meta->zm_bitmap);
size_t i = eidx / 64;
uint64_t map;
if (eidx % 64) {
map = bits[i] & zba_map_mask_ge(uint64_t, eidx);
if (map) {
eidx = __builtin_ctzll(map);
bits[i] ^= 1ull << eidx;
return i * 64 + eidx;
}
i++;
}
for (int j = 0; j < bits_size; i++, j++) {
if (i >= bits_size) {
i = 0;
}
if (__probable(map = bits[i])) {
bits[i] &= map - 1;
return i * 64 + __builtin_ctzll(map);
}
}
zone_page_meta_accounting_panic(zone, meta, "zm_bitmap");
}
/*!
* @function zone_meta_find_and_clear_bit
*
* @brief
* The core of the bitmap allocator: find a bit set in the bitmaps.
*
* @discussion
* This method will round robin through available allocations,
* with a per-core memory of the last allocated element index allocated.
*
* This is done in order to avoid a fully LIFO behavior which makes exploiting
* double-free bugs way too practical.
*
* @param zone The zone we're allocating from.
* @param meta The main metadata for the chunk being allocated from.
*/
static vm_offset_t
zone_meta_find_and_clear_bit(zone_t zone, struct zone_page_metadata *meta)
{
zone_stats_t zs = zpercpu_get(zone->z_stats);
vm_offset_t eidx = zs->zs_alloc_rr + 1;
if (meta->zm_inline_bitmap) {
eidx = zba_scan_bitmap_inline(zone, meta, eidx);
} else {
eidx = zba_scan_bitmap_ref(zone, meta, eidx);
}
zs->zs_alloc_rr = (uint16_t)eidx;
return eidx;
}
/*!
* @function zone_meta_bits_init
*
* @brief
* Initializes the zm_bitmap field(s) for a newly assigned chunk.
*
* @param meta The main metadata for the initialized chunk.
* @param count The number of elements the chunk can hold
* (which might be partial for partially populated chunks).
* @param nbits The maximum nuber of bits that will be used.
*/
static void
zone_meta_bits_init(struct zone_page_metadata *meta,
uint32_t count, uint32_t nbits)
{
static_assert(ZONE_MAX_ALLOC_SIZE / ZONE_MIN_ELEM_SIZE <=
ZBA_GRANULE_BITS << ZBA_MAX_ORDER, "bitmaps will be large enough");
if (meta->zm_inline_bitmap) {
/*
* We're called with the metadata zm_bitmap fields already
* zeroed out.
*/
for (size_t i = 0; 32 * i < count; i++) {
if (32 * i + 32 <= count) {
meta[i].zm_bitmap = ~0u;
} else {
meta[i].zm_bitmap = zba_map_mask_lt(uint32_t, count);
}
}
} else {
uint32_t order = flsll((nbits - 1) / ZBA_GRANULE_BITS);
uint64_t *bits;
assert(order <= ZBA_MAX_ALLOC_ORDER);
assert(count <= ZBA_GRANULE_BITS << order);
zba_lock();
bits = (uint64_t *)zba_alloc(order);
zba_unlock();
for (size_t i = 0; i < 1u << order; i++) {
if (64 * i + 64 <= count) {
bits[i] = ~0ull;
} else if (64 * i < count) {
bits[i] = zba_map_mask_lt(uint64_t, count);
} else {
bits[i] = 0ull;
}
}
meta->zm_bitmap = (uint32_t)((vm_offset_t)bits -
(vm_offset_t)zba_slot_base()) + order;
}
}
/*!
* @function zone_meta_bits_merge
*
* @brief
* Adds elements <code>[start, end)</code> to a chunk being extended.
*
* @param meta The main metadata for the extended chunk.
* @param start The index of the first element to add to the chunk.
* @param end The index of the last (exclusive) element to add.
*/
static void
zone_meta_bits_merge(struct zone_page_metadata *meta,
uint32_t start, uint32_t end)
{
if (meta->zm_inline_bitmap) {
while (start < end) {
size_t s_i = start / 32;
size_t s_e = end / 32;
if (s_i == s_e) {
meta[s_i].zm_bitmap |= zba_map_mask_lt(uint32_t, end) &
zba_map_mask_ge(uint32_t, start);
break;
}
meta[s_i].zm_bitmap |= zba_map_mask_ge(uint32_t, start);
start += 32 - (start % 32);
}
} else {
uint64_t *bits = zba_bits_ref_ptr(meta->zm_bitmap);
while (start < end) {
size_t s_i = start / 64;
size_t s_e = end / 64;
if (s_i == s_e) {
bits[s_i] |= zba_map_mask_lt(uint64_t, end) &
zba_map_mask_ge(uint64_t, start);
break;
}
bits[s_i] |= zba_map_mask_ge(uint64_t, start);
start += 64 - (start % 64);
}
}
}
/*!
* @function zone_bits_free
*
* @brief
* Frees a bitmap to the zone bitmap allocator.
*
* @param bref
* A bitmap reference set by @c zone_meta_bits_init() in a @c zm_bitmap field.
*/
static void
zone_bits_free(uint32_t bref)
{
zba_lock();
zba_free((vm_offset_t)zba_bits_ref_ptr(bref), zba_bits_ref_order(bref));
zba_unlock();
}
/*!
* @function zone_meta_is_free
*
* @brief
* Returns whether a given element appears free.
*/
static bool
zone_meta_is_free(struct zone_page_metadata *meta, zone_element_t ze)
{
vm_offset_t eidx = zone_element_idx(ze);
if (meta->zm_inline_bitmap) {
uint32_t bit = zba_map_bit(uint32_t, eidx);
return meta[zba_map_index(uint32_t, eidx)].zm_bitmap & bit;
} else {
bitmap_t *bits = zba_bits_ref_ptr(meta->zm_bitmap);
uint64_t bit = zba_map_bit(uint64_t, eidx);
return bits[zba_map_index(uint64_t, eidx)] & bit;
}
}
/*!
* @function zone_meta_mark_free
*
* @brief
* Marks an element as free and returns whether it was marked as used.
*/
static bool
zone_meta_mark_free(struct zone_page_metadata *meta, zone_element_t ze)
{
vm_offset_t eidx = zone_element_idx(ze);
if (meta->zm_inline_bitmap) {
uint32_t bit = zba_map_bit(uint32_t, eidx);
if (meta[zba_map_index(uint32_t, eidx)].zm_bitmap & bit) {
return false;
}
meta[zba_map_index(uint32_t, eidx)].zm_bitmap ^= bit;
} else {
bitmap_t *bits = zba_bits_ref_ptr(meta->zm_bitmap);
uint64_t bit = zba_map_bit(uint64_t, eidx);
if (bits[zba_map_index(uint64_t, eidx)] & bit) {
return false;
}
bits[zba_map_index(uint64_t, eidx)] ^= bit;
}
return true;
}
/*!
* @function zone_meta_mark_used
*
* @brief
* Marks an element as used and returns whether it was marked as free
*/
static bool
zone_meta_mark_used(struct zone_page_metadata *meta, zone_element_t ze)
{
vm_offset_t eidx = zone_element_idx(ze);
if (meta->zm_inline_bitmap) {
uint32_t bit = zba_map_bit(uint32_t, eidx);
if (meta[zba_map_index(uint32_t, eidx)].zm_bitmap & bit) {
meta[zba_map_index(uint32_t, eidx)].zm_bitmap ^= bit;
return true;
}
} else {
bitmap_t *bits = zba_bits_ref_ptr(meta->zm_bitmap);
uint64_t bit = zba_map_bit(uint64_t, eidx);
if (bits[zba_map_index(uint64_t, eidx)] & bit) {
bits[zba_map_index(uint64_t, eidx)] ^= bit;
return true;
}
}
return false;
}
#endif /* !ZALLOC_TEST */
/*! @} */
#pragma mark ZTAGS
#if !ZALLOC_TEST
#if VM_MAX_TAG_ZONES
/*
* Zone tagging allows for per "tag" accounting of allocations for the kalloc
* zones only.
*
* There are 3 kinds of tags that can be used:
* - pre-registered VM_KERN_MEMORY_*
* - dynamic tags allocated per call sites in core-kernel (using vm_tag_alloc())
* - per-kext tags computed by IOKit (using the magic VM_TAG_BT marker).
*
* The VM tracks the statistics in lazily allocated structures.
* See vm_tag_will_update_zone(), vm_tag_update_zone_size().
*
* If for some reason the requested tag cannot be accounted for,
* the tag is forced to VM_KERN_MEMORY_KALLOC which is pre-allocated.
*
* Each allocated element also remembers the tag it was assigned,
* in its ztSlot() which lets zalloc/zfree update statistics correctly.
*/
// for zones with tagging enabled:
// calculate a pointer to the tag base entry,
// holding either a uint32_t the first tag offset for a page in the zone map,
// or two uint16_t tags if the page can only hold one or two elements
#define ZTAGBASE(zone, element) \
(&((uint32_t *)zone_tagbase_min)[atop((element) - \
zone_info.zi_map_range[ZONE_ADDR_NATIVE].min_address)])
static vm_offset_t zone_tagbase_min;
static vm_offset_t zone_tagbase_max;
static vm_offset_t zone_tagbase_map_size;
static vm_map_t zone_tagbase_map;
static vm_offset_t zone_tags_min;
static vm_offset_t zone_tags_max;
static vm_offset_t zone_tags_map_size;
static vm_map_t zone_tags_map;
// simple heap allocator for allocating the tags for new memory
static LCK_MTX_EARLY_DECLARE(ztLock, &zone_locks_grp); /* heap lock */
enum{
ztFreeIndexCount = 8,
ztFreeIndexMax = (ztFreeIndexCount - 1),
ztTagsPerBlock = 4
};
struct ztBlock {
#if __LITTLE_ENDIAN__
uint64_t free:1,
next:21,
prev:21,
size:21;
#else
// ztBlock needs free bit least significant
#error !__LITTLE_ENDIAN__
#endif
};
typedef struct ztBlock ztBlock;
static ztBlock * ztBlocks;
static uint32_t ztBlocksCount;
static uint32_t ztBlocksFree;
static uint32_t
ztLog2up(uint32_t size)
{
if (1 == size) {
size = 0;
} else {
size = 32 - __builtin_clz(size - 1);
}
return size;
}
// pointer to the tag for an element
static vm_tag_t *
ztSlot(zone_t zone, vm_offset_t element)
{
vm_tag_t *result;
if (zone->tags_inline) {
result = (vm_tag_t *)ZTAGBASE(zone, element);
if ((PAGE_MASK & element) >= zone_elem_size(zone)) {
result++;
}
} else {
result = &((vm_tag_t *)zone_tags_min)[ZTAGBASE(zone, element)[0] +
(element & PAGE_MASK) / zone_elem_size(zone)];
}
return result;
}
static uint32_t
ztLog2down(uint32_t size)
{
size = 31 - __builtin_clz(size);
return size;
}
static void
ztFault(vm_map_t map, const void * address, size_t size, uint32_t flags)
{
vm_map_offset_t addr = (vm_map_offset_t) address;
vm_map_offset_t page, end;
page = trunc_page(addr);
end = round_page(addr + size);
for (; page < end; page += page_size) {
if (!pmap_find_phys(kernel_pmap, page)) {
kern_return_t __unused
ret = kernel_memory_populate(map, page, PAGE_SIZE,
KMA_KOBJECT | flags, VM_KERN_MEMORY_DIAG);
assert(ret == KERN_SUCCESS);
}
}
}
static boolean_t
ztPresent(const void * address, size_t size)
{
vm_map_offset_t addr = (vm_map_offset_t) address;
vm_map_offset_t page, end;
boolean_t result;
page = trunc_page(addr);
end = round_page(addr + size);
for (result = TRUE; (page < end); page += page_size) {
result = pmap_find_phys(kernel_pmap, page);
if (!result) {
break;
}
}
return result;
}
void __unused
ztDump(boolean_t sanity);
void __unused
ztDump(boolean_t sanity)
{
uint32_t q, cq, p;
for (q = 0; q <= ztFreeIndexMax; q++) {
p = q;
do{
if (sanity) {
cq = ztLog2down(ztBlocks[p].size);
if (cq > ztFreeIndexMax) {
cq = ztFreeIndexMax;
}
if (!ztBlocks[p].free
|| ((p != q) && (q != cq))
|| (ztBlocks[ztBlocks[p].next].prev != p)
|| (ztBlocks[ztBlocks[p].prev].next != p)) {
kprintf("zterror at %d", p);
ztDump(FALSE);
kprintf("zterror at %d", p);
assert(FALSE);
}
continue;
}
kprintf("zt[%03d]%c %d, %d, %d\n",
p, ztBlocks[p].free ? 'F' : 'A',
ztBlocks[p].next, ztBlocks[p].prev,
ztBlocks[p].size);
p = ztBlocks[p].next;
if (p == q) {
break;
}
}while (p != q);
if (!sanity) {
printf("\n");
}
}
if (!sanity) {
printf("-----------------------\n");
}
}
#define ZTBDEQ(idx) \
ztBlocks[ztBlocks[(idx)].prev].next = ztBlocks[(idx)].next; \
ztBlocks[ztBlocks[(idx)].next].prev = ztBlocks[(idx)].prev;
static void
ztFree(zone_t zone __unused, uint32_t index, uint32_t count)
{
uint32_t q, w, p, size, merge;
assert(count);
ztBlocksFree += count;
// merge with preceding
merge = (index + count);
if ((merge < ztBlocksCount)
&& ztPresent(&ztBlocks[merge], sizeof(ztBlocks[merge]))
&& ztBlocks[merge].free) {
ZTBDEQ(merge);
count += ztBlocks[merge].size;
}
// merge with following
merge = (index - 1);
if ((merge > ztFreeIndexMax)
&& ztPresent(&ztBlocks[merge], sizeof(ztBlocks[merge]))
&& ztBlocks[merge].free) {
size = ztBlocks[merge].size;
count += size;
index -= size;
ZTBDEQ(index);
}
q = ztLog2down(count);
if (q > ztFreeIndexMax) {
q = ztFreeIndexMax;
}
w = q;
// queue in order of size
while (TRUE) {
p = ztBlocks[w].next;
if (p == q) {
break;
}
if (ztBlocks[p].size >= count) {
break;
}
w = p;
}
ztBlocks[p].prev = index;
ztBlocks[w].next = index;
// fault in first
ztFault(zone_tags_map, &ztBlocks[index], sizeof(ztBlocks[index]), 0);
// mark first & last with free flag and size
ztBlocks[index].free = TRUE;
ztBlocks[index].size = count;
ztBlocks[index].prev = w;
ztBlocks[index].next = p;
if (count > 1) {
index += (count - 1);
// fault in last
ztFault(zone_tags_map, &ztBlocks[index], sizeof(ztBlocks[index]), 0);
ztBlocks[index].free = TRUE;
ztBlocks[index].size = count;
}
}
static uint32_t
ztAlloc(zone_t zone, uint32_t count)
{
uint32_t q, w, p, leftover;
assert(count);
q = ztLog2up(count);
if (q > ztFreeIndexMax) {
q = ztFreeIndexMax;
}
do{
w = q;
while (TRUE) {
p = ztBlocks[w].next;
if (p == q) {
break;
}
if (ztBlocks[p].size >= count) {
// dequeue, mark both ends allocated
ztBlocks[w].next = ztBlocks[p].next;
ztBlocks[ztBlocks[p].next].prev = w;
ztBlocks[p].free = FALSE;
ztBlocksFree -= ztBlocks[p].size;
if (ztBlocks[p].size > 1) {
ztBlocks[p + ztBlocks[p].size - 1].free = FALSE;
}
// fault all the allocation
ztFault(zone_tags_map, &ztBlocks[p], count * sizeof(ztBlocks[p]), 0);
// mark last as allocated
if (count > 1) {
ztBlocks[p + count - 1].free = FALSE;
}
// free remainder
leftover = ztBlocks[p].size - count;
if (leftover) {
ztFree(zone, p + ztBlocks[p].size - leftover, leftover);
}
return p;
}
w = p;
}
q++;
}while (q <= ztFreeIndexMax);
return -1U;
}
__startup_func
static void
zone_tagging_init(vm_size_t max_zonemap_size)
{
kern_return_t ret;
vm_map_kernel_flags_t vmk_flags;
uint32_t idx;
// allocate submaps VM_KERN_MEMORY_DIAG
zone_tagbase_map_size = atop(max_zonemap_size) * sizeof(uint32_t);
vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
vmk_flags.vmkf_permanent = TRUE;
ret = kmem_suballoc(kernel_map, &zone_tagbase_min, zone_tagbase_map_size,
FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_DIAG,
&zone_tagbase_map);
if (ret != KERN_SUCCESS) {
panic("zone_init: kmem_suballoc failed");
}
zone_tagbase_max = zone_tagbase_min + round_page(zone_tagbase_map_size);
zone_tags_map_size = 2048 * 1024 * sizeof(vm_tag_t);
vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
vmk_flags.vmkf_permanent = TRUE;
ret = kmem_suballoc(kernel_map, &zone_tags_min, zone_tags_map_size,
FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_DIAG,
&zone_tags_map);
if (ret != KERN_SUCCESS) {
panic("zone_init: kmem_suballoc failed");
}
zone_tags_max = zone_tags_min + round_page(zone_tags_map_size);
ztBlocks = (ztBlock *) zone_tags_min;
ztBlocksCount = (uint32_t)(zone_tags_map_size / sizeof(ztBlock));
// initialize the qheads
lck_mtx_lock(&ztLock);
ztFault(zone_tags_map, &ztBlocks[0], sizeof(ztBlocks[0]), 0);
for (idx = 0; idx < ztFreeIndexCount; idx++) {
ztBlocks[idx].free = TRUE;
ztBlocks[idx].next = idx;
ztBlocks[idx].prev = idx;
ztBlocks[idx].size = 0;
}
// free remaining space
ztFree(NULL, ztFreeIndexCount, ztBlocksCount - ztFreeIndexCount);
lck_mtx_unlock(&ztLock);
}
static void
ztMemoryAdd(zone_t zone, vm_offset_t mem, vm_size_t size)
{
uint32_t * tagbase;
uint32_t count, block, blocks, idx;
size_t pages;
pages = atop(size);
tagbase = ZTAGBASE(zone, mem);
lck_mtx_lock(&ztLock);
// fault tagbase
ztFault(zone_tagbase_map, tagbase, pages * sizeof(uint32_t), 0);
if (!zone->tags_inline) {
// allocate tags
count = (uint32_t)(size / zone_elem_size(zone));
blocks = ((count + ztTagsPerBlock - 1) / ztTagsPerBlock);
block = ztAlloc(zone, blocks);
if (-1U == block) {
ztDump(false);
}
assert(-1U != block);
}
lck_mtx_unlock(&ztLock);
if (!zone->tags_inline) {
// set tag base for each page
block *= ztTagsPerBlock;
for (idx = 0; idx < pages; idx++) {
vm_offset_t esize = zone_elem_size(zone);
tagbase[idx] = block + (uint32_t)((ptoa(idx) + esize - 1) / esize);
}
}
}
static void
ztMemoryRemove(zone_t zone, vm_offset_t mem, vm_size_t size)
{
uint32_t * tagbase;
uint32_t count, block, blocks, idx;
size_t pages;
// set tag base for each page
pages = atop(size);
tagbase = ZTAGBASE(zone, mem);
block = tagbase[0];
for (idx = 0; idx < pages; idx++) {
tagbase[idx] = 0xFFFFFFFF;
}
lck_mtx_lock(&ztLock);
if (!zone->tags_inline) {
count = (uint32_t)(size / zone_elem_size(zone));
blocks = ((count + ztTagsPerBlock - 1) / ztTagsPerBlock);
assert(block != 0xFFFFFFFF);
block /= ztTagsPerBlock;
ztFree(NULL /* zone is unlocked */, block, blocks);
}
lck_mtx_unlock(&ztLock);
}
uint32_t
zone_index_from_tag_index(uint32_t tag_zone_index, vm_size_t * elem_size)
{
simple_lock(&all_zones_lock, &zone_locks_grp);
zone_index_foreach(idx) {
zone_t z = &zone_array[idx];
if (!z->tags) {
continue;
}
if (tag_zone_index != z->tag_zone_index) {
continue;
}
*elem_size = zone_elem_size(z);
simple_unlock(&all_zones_lock);
return idx;
}
simple_unlock(&all_zones_lock);
return -1U;
}
#endif /* VM_MAX_TAG_ZONES */
#endif /* !ZALLOC_TEST */
#pragma mark zalloc helpers
#if !ZALLOC_TEST
__pure2
static inline uint16_t
zc_mag_size(void)
{
return zc_magazine_size;
}
__attribute__((noinline, cold))
static void
zone_lock_was_contended(zone_t zone, zone_cache_t zc)
{
lck_spin_lock_nopreempt(&zone->z_lock);
/*
* If zone caching has been disabled due to memory pressure,
* then recording contention is not useful, give the system
* time to recover.
*/
if (__improbable(zone_caching_disabled)) {
return;
}
zone->z_contention_cur++;
if (zc == NULL || zc->zc_depot_max >= INT16_MAX * zc_mag_size()) {
return;
}
/*
* Let the depot grow based on how bad the contention is,
* and how populated the zone is.
*/
if (zone->z_contention_wma < 2 * Z_CONTENTION_WMA_UNIT) {
if (zc->zc_depot_max * zpercpu_count() * 20u >=
zone->z_elems_avail) {
return;
}
}
if (zone->z_contention_wma < 4 * Z_CONTENTION_WMA_UNIT) {
if (zc->zc_depot_max * zpercpu_count() * 10u >=
zone->z_elems_avail) {
return;
}
}
if (!zc_grow_threshold || zone->z_contention_wma <
zc_grow_threshold * Z_CONTENTION_WMA_UNIT) {
return;
}
zc->zc_depot_max++;
}
static inline void
zone_lock_nopreempt_check_contention(zone_t zone, zone_cache_t zc)
{
if (lck_spin_try_lock_nopreempt(&zone->z_lock)) {
return;
}
zone_lock_was_contended(zone, zc);
}
static inline void
zone_lock_check_contention(zone_t zone, zone_cache_t zc)
{
disable_preemption();
zone_lock_nopreempt_check_contention(zone, zc);
}
static inline void
zone_unlock_nopreempt(zone_t zone)
{
lck_spin_unlock_nopreempt(&zone->z_lock);
}
static inline void
zone_depot_lock_nopreempt(zone_cache_t zc)
{
hw_lock_bit_nopreempt(&zc->zc_depot_lock, 0, &zone_locks_grp);
}
static inline void
zone_depot_unlock_nopreempt(zone_cache_t zc)
{
hw_unlock_bit_nopreempt(&zc->zc_depot_lock, 0);
}
static inline void
zone_depot_lock(zone_cache_t zc)
{
hw_lock_bit(&zc->zc_depot_lock, 0, &zone_locks_grp);
}
static inline void
zone_depot_unlock(zone_cache_t zc)
{
hw_unlock_bit(&zc->zc_depot_lock, 0);
}
const char *
zone_name(zone_t z)
{
return z->z_name;
}
const char *
zone_heap_name(zone_t z)
{
if (__probable(z->kalloc_heap < KHEAP_ID_COUNT)) {
return kalloc_heap_names[z->kalloc_heap];
}
return "invalid";
}
static uint32_t
zone_alloc_pages_for_nelems(zone_t z, vm_size_t max_elems)
{
vm_size_t elem_count, chunks;
elem_count = ptoa(z->z_percpu ? 1 : z->z_chunk_pages) / zone_elem_size(z);
chunks = (max_elems + elem_count - 1) / elem_count;
return (uint32_t)MIN(UINT32_MAX, chunks * z->z_chunk_pages);
}
static inline vm_size_t
zone_submaps_approx_size(void)
{
vm_size_t size = 0;
for (unsigned idx = 0; idx <= zone_last_submap_idx; idx++) {
size += zone_submaps[idx]->size;
}
return size;
}
static void
zone_cache_swap_magazines(zone_cache_t cache)
{
uint16_t count_a = cache->zc_alloc_cur;
uint16_t count_f = cache->zc_free_cur;
zone_element_t *elems_a = cache->zc_alloc_elems;
zone_element_t *elems_f = cache->zc_free_elems;
z_debug_assert(count_a <= zc_mag_size());
z_debug_assert(count_f <= zc_mag_size());
cache->zc_alloc_cur = count_f;
cache->zc_free_cur = count_a;
cache->zc_alloc_elems = elems_f;
cache->zc_free_elems = elems_a;
}
/*!
* @function zone_magazine_load
*
* @brief
* Cache the value of @c zm_cur on the cache to avoid a dependent load
* on the allocation fastpath.
*/
static void
zone_magazine_load(uint16_t *count, zone_element_t **elems, zone_magazine_t mag)
{
z_debug_assert(mag->zm_cur <= zc_mag_size());
*count = mag->zm_cur;
*elems = mag->zm_elems;
}
/*!
* @function zone_magazine_replace
*
* @brief
* Unlod a magazine and load a new one instead.
*/
static zone_magazine_t
zone_magazine_replace(uint16_t *count, zone_element_t **elems,
zone_magazine_t mag)
{
zone_magazine_t old;
old = (zone_magazine_t)((uintptr_t)*elems -
offsetof(struct zone_magazine, zm_elems));
old->zm_cur = *count;
z_debug_assert(old->zm_cur <= zc_mag_size());
zone_magazine_load(count, elems, mag);
return old;
}
static zone_magazine_t
zone_magazine_alloc(zalloc_flags_t flags)
{
return zalloc_ext(zc_magazine_zone, zc_magazine_zone->z_stats,
flags | Z_ZERO);
}
static void
zone_magazine_free(zone_magazine_t mag)
{
zfree_ext(zc_magazine_zone, zc_magazine_zone->z_stats, mag);
}
static void
zone_enable_caching(zone_t zone)
{
zone_cache_t caches;
caches = zalloc_percpu_permanent_type(struct zone_cache);
zpercpu_foreach(zc, caches) {
zone_magazine_load(&zc->zc_alloc_cur, &zc->zc_alloc_elems,
zone_magazine_alloc(Z_WAITOK | Z_NOFAIL));
zone_magazine_load(&zc->zc_free_cur, &zc->zc_free_elems,
zone_magazine_alloc(Z_WAITOK | Z_NOFAIL));
STAILQ_INIT(&zc->zc_depot);
}
if (os_atomic_xchg(&zone->z_pcpu_cache, caches, release)) {
panic("allocating caches for zone %s twice", zone->z_name);
}
}
bool
zone_maps_owned(vm_address_t addr, vm_size_t size)
{
return from_zone_map(addr, size, ZONE_ADDR_NATIVE);
}
void
zone_map_sizes(
vm_map_size_t *psize,
vm_map_size_t *pfree,
vm_map_size_t *plargest_free)
{
vm_map_size_t size, free, largest;
vm_map_sizes(zone_submaps[0], psize, pfree, plargest_free);
for (uint32_t i = 1; i <= zone_last_submap_idx; i++) {
vm_map_sizes(zone_submaps[i], &size, &free, &largest);
*psize += size;
*pfree += free;
*plargest_free = MAX(*plargest_free, largest);
}
}
__attribute__((always_inline))
vm_map_t
zone_submap(zone_t zone)
{
return zone_submaps[zone->z_submap_idx];
}
unsigned
zpercpu_count(void)
{
return zpercpu_early_count;
}
int
track_this_zone(const char *zonename, const char *logname)
{
unsigned int len;
const char *zc = zonename;
const char *lc = logname;
/*
* Compare the strings. We bound the compare by MAX_ZONE_NAME.
*/
for (len = 1; len <= MAX_ZONE_NAME; zc++, lc++, len++) {
/*
* If the current characters don't match, check for a space in
* in the zone name and a corresponding period in the log name.
* If that's not there, then the strings don't match.
*/
if (*zc != *lc && !(*zc == ' ' && *lc == '.')) {
break;
}
/*
* The strings are equal so far. If we're at the end, then it's a match.
*/
if (*zc == '\0') {
return TRUE;
}
}
return FALSE;
}
#if DEBUG || DEVELOPMENT
vm_size_t
zone_element_info(void *addr, vm_tag_t * ptag)
{
vm_size_t size = 0;
vm_tag_t tag = VM_KERN_MEMORY_NONE;
struct zone *src_zone;
if (from_zone_map(addr, sizeof(void *), ZONE_ADDR_NATIVE) ||
from_zone_map(addr, sizeof(void *), ZONE_ADDR_FOREIGN)) {
src_zone = &zone_array[zone_index_from_ptr(addr)];
#if VM_MAX_TAG_ZONES
if (__improbable(src_zone->tags)) {
tag = *ztSlot(src_zone, (vm_offset_t)addr) >> 1;
}
#endif /* VM_MAX_TAG_ZONES */
size = zone_elem_size(src_zone);
} else {
#if CONFIG_GZALLOC
gzalloc_element_size(addr, NULL, &size);
#endif /* CONFIG_GZALLOC */
}
*ptag = tag;
return size;
}
#endif /* DEBUG || DEVELOPMENT */
/* The backup pointer is stored in the last pointer-sized location in an element. */
__header_always_inline vm_offset_t *
get_primary_ptr(vm_offset_t elem)
{
return (vm_offset_t *)elem;
}
__header_always_inline vm_offset_t *
get_backup_ptr(vm_offset_t elem, vm_size_t elem_size)
{
return (vm_offset_t *)(elem + elem_size - sizeof(vm_offset_t));
}
#endif /* !ZALLOC_TEST */
#pragma mark Zone poisoning/zeroing and early random
#if !ZALLOC_TEST
#define ZONE_ENTROPY_CNT 2
static struct zone_bool_gen {
struct bool_gen zbg_bg;
uint32_t zbg_entropy[ZONE_ENTROPY_CNT];
} zone_bool_gen[MAX_CPUS];
/*
* Initialize zone poisoning
* called from zone_bootstrap before any allocations are made from zalloc
*/
__startup_func
static void
zp_bootstrap(void)
{
char temp_buf[16];
/*
* Initialize canary random cookie.
*
* Make sure that (zp_canary ^ pointer) have non zero low bits (01)
* different from ZONE_POISON (11).
*
* On LP64, have (zp_canary ^ pointer) have the high bits equal 0xC0FFEE...
*/
static_assert(ZONE_POISON % 4 == 3);
zp_canary = (uintptr_t)early_random();
#if __LP64__
zp_canary &= 0x000000fffffffffc;
zp_canary |= 0xc0ffee0000000001 ^ 0xffffff0000000000;
#else
zp_canary &= 0xfffffffc;
zp_canary |= 0x00000001;
#endif
/* -zp: enable poisoning for every alloc and free */
if (PE_parse_boot_argn("-zp", temp_buf, sizeof(temp_buf))) {
zp_factor = 1;
}
/* -no-zp: disable poisoning */
if (PE_parse_boot_argn("-no-zp", temp_buf, sizeof(temp_buf))) {
zp_factor = 0;
printf("Zone poisoning disabled\n");
}
zpercpu_foreach_cpu(cpu) {
random_bool_init(&zone_bool_gen[cpu].zbg_bg);
}
}
static inline uint32_t
zone_poison_count_init(zone_t zone)
{
return zp_factor + (((uint32_t)zone_elem_size(zone)) >> zp_scale) ^
(mach_absolute_time() & 0x7);
}
/*
* Zero the element if zone has z_free_zeroes flag set else poison
* the element if zs_poison_seqno hits 0.
*/
static zprot_mode_t
zfree_clear_or_poison(zone_t zone, vm_offset_t addr, vm_offset_t elem_size)
{
if (zone->z_free_zeroes) {
if (zone->z_percpu) {
zpercpu_foreach_cpu(i) {
bzero((void *)(addr + ptoa(i)), elem_size);
}
} else {
bzero((void *)addr, elem_size);
}
return ZPM_ZERO;
}
zprot_mode_t poison = ZPM_AUTO;
#if ZALLOC_ENABLE_POISONING
if (__improbable(zp_factor == 1)) {
poison = ZPM_POISON;
} else if (__probable(zp_factor != 0)) {
uint32_t *seqnop = &zpercpu_get(zone->z_stats)->zs_poison_seqno;
uint32_t seqno = os_atomic_load(seqnop, relaxed);
if (seqno == 0) {
os_atomic_store(seqnop, zone_poison_count_init(zone), relaxed);
poison = ZPM_POISON;
} else {
os_atomic_store(seqnop, seqno - 1, relaxed);
}
}
if (poison == ZPM_POISON) {
/* memset_pattern{4|8} could help make this faster: <rdar://problem/4662004> */
for (size_t i = 0; i < elem_size / sizeof(vm_offset_t); i++) {
((vm_offset_t *)addr)[i] = ZONE_POISON;
}
} else {
/*
* Set a canary at the extremities.
*
* Zero first zp_min_size bytes of elements that aren't being
* poisoned.
*
* Element size is larger than zp_min_size in this path,
* zones with smaller elements have z_free_zeroes set.
*/
*get_primary_ptr(addr) = zp_canary ^ (uintptr_t)addr;
bzero((void *)addr + sizeof(vm_offset_t),
zp_min_size - sizeof(vm_offset_t));
*get_backup_ptr(addr, elem_size) = zp_canary ^ (uintptr_t)addr;
poison = ZPM_CANARY;
}
#endif /* ZALLOC_ENABLE_POISONING */
return poison;
}
#if ZALLOC_ENABLE_POISONING
__abortlike
static void
zalloc_uaf_panic(zone_t z, uintptr_t elem, size_t size, zprot_mode_t zpm)
{
uint32_t esize = (uint32_t)zone_elem_size(z);
uint32_t first_offs = ~0u;
uintptr_t first_bits = 0, v;
char buf[1024];
int pos = 0;
const char *how;
#if __LP64__
#define ZPF "0x%016lx"
#else
#define ZPF "0x%08lx"
#endif
buf[0] = '\0';
if (zpm == ZPM_CANARY) {
how = "canaries";
v = *get_primary_ptr(elem);
if (v != (elem ^ zp_canary)) {
pos += scnprintf(buf + pos, sizeof(buf) - pos, "\n"
"%5d: got "ZPF", want "ZPF" (xor: "ZPF")",
0, v, (elem ^ zp_canary), (v ^ elem ^ zp_canary));
if (first_offs > 0) {
first_offs = 0;
first_bits = v;
}
}
v = *get_backup_ptr(elem, esize);
if (v != (elem ^ zp_canary)) {
pos += scnprintf(buf + pos, sizeof(buf) - pos, "\n"
"%5d: got "ZPF", want "ZPF" (xor: "ZPF")",
esize - (int)sizeof(v), v, (elem ^ zp_canary),
(v ^ elem ^ zp_canary));
if (first_offs > esize - sizeof(v)) {
first_offs = esize - sizeof(v);
first_bits = v;
}
}
for (uint32_t o = sizeof(v); o < zp_min_size; o += sizeof(v)) {
if ((v = *(uintptr_t *)(elem + o)) == 0) {
continue;
}
pos += scnprintf(buf + pos, sizeof(buf) - pos, "\n"
"%5d: "ZPF, o, v);
if (first_offs > o) {
first_offs = o;
first_bits = v;
}
}
} else if (zpm == ZPM_ZERO) {
how = "zero";
for (uint32_t o = 0; o < size; o += sizeof(v)) {
if ((v = *(uintptr_t *)(elem + o)) == 0) {
continue;
}
pos += scnprintf(buf + pos, sizeof(buf) - pos, "\n"
"%5d: "ZPF, o, v);
if (first_offs > o) {
first_offs = o;
first_bits = v;
}
}
} else {
how = "poison";
for (uint32_t o = 0; o < size; o += sizeof(v)) {
if ((v = *(uintptr_t *)(elem + o)) == ZONE_POISON) {
continue;
}
pos += scnprintf(buf + pos, sizeof(buf) - pos, "\n"
"%5d: "ZPF" (xor: "ZPF")",
o, v, (v ^ ZONE_POISON));
if (first_offs > o) {
first_offs = o;
first_bits = v;
}
}
}
(panic)("[%s%s]: element modified after free "
"(off:%d, val:"ZPF", sz:%d, ptr:%p, prot:%s)%s",
zone_heap_name(z), zone_name(z),
first_offs, first_bits, esize, (void *)elem, how, buf);
#undef ZPF
}
static void
zalloc_validate_element_zero(zone_t zone, vm_offset_t elem, vm_size_t size)
{
if (memcmp_zero_ptr_aligned((void *)elem, size)) {
zalloc_uaf_panic(zone, elem, size, ZPM_ZERO);
}
if (!zone->z_percpu) {
return;
}
for (size_t i = zpercpu_count(); --i > 0;) {
elem += PAGE_SIZE;
if (memcmp_zero_ptr_aligned((void *)elem, size)) {
zalloc_uaf_panic(zone, elem, size, ZPM_ZERO);
}
}
}
#if __arm64__ || __arm__
typedef __attribute__((ext_vector_type(2))) vm_offset_t zpair_t;
#else
typedef struct {
vm_offset_t x;
vm_offset_t y;
} zpair_t;
#endif
__attribute__((noinline))
static void
zalloc_validate_element_poison(zone_t zone, vm_offset_t elem, vm_size_t size)
{
vm_offset_t p = elem;
vm_offset_t end = elem + size;
const zpair_t poison = { ZONE_POISON, ZONE_POISON };
zpair_t a, b;
a.x = *(const vm_offset_t *)p;
a.y = *(const vm_offset_t *)(end - sizeof(vm_offset_t));
a.x ^= poison.x;
a.y ^= poison.y;
/*
* align p to the next double-wide boundary
* align end to the previous double-wide boundary
*/
p = (p + sizeof(zpair_t) - 1) & -sizeof(zpair_t);
end &= -sizeof(zpair_t);
if ((end - p) % (2 * sizeof(zpair_t)) == 0) {
b.y = 0;
b.y = 0;
} else {
end -= sizeof(zpair_t);
b.x = ((zpair_t *)end)[0].x ^ poison.x;
b.y = ((zpair_t *)end)[0].y ^ poison.y;
}
for (; p < end; p += 2 * sizeof(zpair_t)) {
a.x |= ((zpair_t *)p)[0].x ^ poison.x;
a.y |= ((zpair_t *)p)[0].y ^ poison.y;
b.x |= ((zpair_t *)p)[1].x ^ poison.x;
b.y |= ((zpair_t *)p)[1].y ^ poison.y;
}
a.x |= b.x;
a.y |= b.y;
if (a.x || a.y) {
zalloc_uaf_panic(zone, elem, size, ZPM_POISON);
}
}
static void
zalloc_validate_element(zone_t zone, vm_offset_t elem, vm_size_t size,
zprot_mode_t zpm)
{
vm_offset_t *primary = get_primary_ptr(elem);
vm_offset_t *backup = get_backup_ptr(elem, size);
#if CONFIG_GZALLOC
if (zone->gzalloc_tracked) {
return;
}
#endif /* CONFIG_GZALLOC */
if (zone->z_free_zeroes) {
return zalloc_validate_element_zero(zone, elem, size);
}
switch (zpm) {
case ZPM_AUTO:
if (*backup == 0) {
size -= sizeof(vm_size_t);
return zalloc_validate_element_zero(zone, elem, size);
}
if (*backup == ZONE_POISON) {
size -= sizeof(vm_size_t);
return zalloc_validate_element_poison(zone, elem, size);
}
OS_FALLTHROUGH;
case ZPM_CANARY:
if ((*primary ^ zp_canary) != elem || (*backup ^ zp_canary) != elem) {
zalloc_uaf_panic(zone, elem, size, ZPM_CANARY);
}
*primary = *backup = 0;
size = zp_min_size;
OS_FALLTHROUGH;
case ZPM_ZERO:
return zalloc_validate_element_zero(zone, elem, size);
case ZPM_POISON:
return zalloc_validate_element_poison(zone, elem, size);
}
}
#endif /* ZALLOC_ENABLE_POISONING */
#if ZALLOC_EARLY_GAPS
__attribute__((noinline))
static void
zone_early_gap_drop(int n)
{
while (n-- > 0) {
zone_t zone0 = &zone_array[0];
struct zone_page_metadata *meta = NULL;
vm_offset_t addr;
uint16_t pages;
vm_map_t map;
lck_mtx_lock(&zone_metadata_region_lck);
if (!zone_pva_is_null(zone0->z_pageq_va)) {
meta = zone_meta_queue_pop_native(zone0,
&zone0->z_pageq_va, &addr);
map = zone_submaps[meta->zm_chunk_len];
pages = meta->zm_alloc_size;
__builtin_bzero(meta, sizeof(struct zone_page_metadata));
}
lck_mtx_unlock(&zone_metadata_region_lck);
if (!meta) {
break;
}
kmem_free(map, addr, ptoa(pages));
}
}
static void
zone_early_gap_add(zone_t z, uint16_t pages)
{
struct zone_page_metadata *meta = NULL;
zone_t zone0 = &zone_array[0];
kern_return_t kr;
vm_offset_t addr;
kma_flags_t kmaflags = KMA_KOBJECT | KMA_ZERO | KMA_VAONLY;
if (z->z_submap_idx == Z_SUBMAP_IDX_GENERAL &&
z->kalloc_heap != KHEAP_ID_NONE) {
kmaflags |= KMA_KHEAP;
}
kr = kernel_memory_allocate(zone_submap(z), &addr, ptoa(pages), 0,
kmaflags, VM_KERN_MEMORY_ZONE);
if (kr != KERN_SUCCESS) {
panic("unable to allocate early gap (%d pages): %d", pages, kr);
}
zone_meta_populate(addr, ptoa(pages));
meta = zone_meta_from_addr(addr);
meta->zm_alloc_size = pages;
meta->zm_chunk_len = z->z_submap_idx;
lck_mtx_lock(&zone_metadata_region_lck);
zone_meta_queue_push(zone0, &zone0->z_pageq_va, meta);
lck_mtx_unlock(&zone_metadata_region_lck);
}
/*
* Roughly until pd1 is made, introduce random gaps
* between allocated pages.
*
* This way the early boot allocations are not in a completely
* predictible order and relative position.
*
* Those gaps are returned to the maps afterwards.
*
* We abuse the zone 0 (which is unused) "va" pageq to remember
* those ranges.
*/
__attribute__((noinline))
static void
zone_allocate_random_early_gap(zone_t z)
{
int16_t pages = early_random() % 16;
/*
* 6% of the time: drop 2 gaps
* 25% of the time: drop 1 gap
* 37% of the time: do nothing
* 18% of the time: add 1 gap
* 12% of the time: add 2 gaps
*/
if (pages > 10) {
zone_early_gap_drop(pages == 15 ? 2 : 1);
}
if (pages < 5) {
/* values are 6 through 16 */
zone_early_gap_add(z, 6 + 2 * pages);
}
if (pages < 2) {
zone_early_gap_add(z, 6 + early_random() % 16);
}
}
static inline void
zone_cleanup_early_gaps_if_needed(void)
{
if (__improbable(!zone_pva_is_null(zone_array[0].z_pageq_va))) {
zone_early_gap_drop(10);
}
}
#endif /* ZALLOC_EARLY_GAPS */
static void
zone_early_scramble_rr(zone_t zone, zone_stats_t zstats)
{
int cpu = cpu_number();
zone_stats_t zs = zpercpu_get_cpu(zstats, cpu);
uint32_t bits;
bits = random_bool_gen_bits(&zone_bool_gen[cpu].zbg_bg,
zone_bool_gen[cpu].zbg_entropy, ZONE_ENTROPY_CNT, 8);
zs->zs_alloc_rr += bits;
zs->zs_alloc_rr %= zone->z_chunk_elems;
}
#endif /* !ZALLOC_TEST */
#pragma mark Zone Leak Detection
#if !ZALLOC_TEST
/*
* Zone leak debugging code
*
* When enabled, this code keeps a log to track allocations to a particular zone that have not
* yet been freed. Examining this log will reveal the source of a zone leak. The log is allocated
* only when logging is enabled, so there is no effect on the system when it's turned off. Logging is
* off by default.
*
* Enable the logging via the boot-args. Add the parameter "zlog=<zone>" to boot-args where <zone>
* is the name of the zone you wish to log.
*
* This code only tracks one zone, so you need to identify which one is leaking first.
* Generally, you'll know you have a leak when you get a "zalloc retry failed 3" panic from the zone
* garbage collector. Note that the zone name printed in the panic message is not necessarily the one
* containing the leak. So do a zprint from gdb and locate the zone with the bloated size. This
* is most likely the problem zone, so set zlog in boot-args to this zone name, reboot and re-run the test. The
* next time it panics with this message, examine the log using the kgmacros zstack, findoldest and countpcs.
* See the help in the kgmacros for usage info.
*
*
* Zone corruption logging
*
* Logging can also be used to help identify the source of a zone corruption. First, identify the zone
* that is being corrupted, then add "-zc zlog=<zone name>" to the boot-args. When -zc is used in conjunction
* with zlog, it changes the logging style to track both allocations and frees to the zone. So when the
* corruption is detected, examining the log will show you the stack traces of the callers who last allocated
* and freed any particular element in the zone. Use the findelem kgmacro with the address of the element that's been
* corrupted to examine its history. This should lead to the source of the corruption.
*/
/* Returns TRUE if we rolled over the counter at factor */
__header_always_inline bool
sample_counter(volatile uint32_t *count_p, uint32_t factor)
{
uint32_t old_count, new_count = 0;
if (count_p != NULL) {
os_atomic_rmw_loop(count_p, old_count, new_count, relaxed, {
new_count = old_count + 1;
if (new_count >= factor) {
new_count = 0;
}
});
}
return new_count == 0;
}
#if ZONE_ENABLE_LOGGING
/* Log allocations and frees to help debug a zone element corruption */
static TUNABLE(bool, corruption_debug_flag, "-zc", false);
#define MAX_NUM_ZONES_ALLOWED_LOGGING 10 /* Maximum 10 zones can be logged at once */
static int max_num_zones_to_log = MAX_NUM_ZONES_ALLOWED_LOGGING;
static int num_zones_logged = 0;
/*
* The number of records in the log is configurable via the zrecs parameter in boot-args. Set this to
* the number of records you want in the log. For example, "zrecs=10" sets it to 10 records. Since this
* is the number of stacks suspected of leaking, we don't need many records.
*/
#if defined(__LP64__)
#define ZRECORDS_MAX 2560 /* Max records allowed in the log */
#else
#define ZRECORDS_MAX 1536 /* Max records allowed in the log */
#endif
#define ZRECORDS_DEFAULT 1024 /* default records in log if zrecs is not specificed in boot-args */
static TUNABLE(uint32_t, log_records, "zrecs", ZRECORDS_DEFAULT);
static void
zone_enable_logging(zone_t z)
{
z->zlog_btlog = btlog_create(log_records, MAX_ZTRACE_DEPTH,
(corruption_debug_flag == FALSE) /* caller_will_remove_entries_for_element? */);
if (z->zlog_btlog) {
printf("zone: logging started for zone %s%s\n",
zone_heap_name(z), z->z_name);
} else {
printf("zone: couldn't allocate memory for zrecords, turning off zleak logging\n");
z->zone_logging = false;
}
}
/**
* @function zone_setup_logging
*
* @abstract
* Optionally sets up a zone for logging.
*
* @discussion
* We recognized two boot-args:
*
* zlog=<zone_to_log>
* zrecs=<num_records_in_log>
*
* The zlog arg is used to specify the zone name that should be logged,
* and zrecs is used to control the size of the log.
*
* If zrecs is not specified, a default value is used.
*/
static void
zone_setup_logging(zone_t z)
{
char zone_name[MAX_ZONE_NAME]; /* Temp. buffer for the zone name */
char zlog_name[MAX_ZONE_NAME]; /* Temp. buffer to create the strings zlog1, zlog2 etc... */
char zlog_val[MAX_ZONE_NAME]; /* the zone name we're logging, if any */
/*
* Don't allow more than ZRECORDS_MAX records even if the user asked for more.
*
* This prevents accidentally hogging too much kernel memory
* and making the system unusable.
*/
if (log_records > ZRECORDS_MAX) {
log_records = ZRECORDS_MAX;
}
/*
* Append kalloc heap name to zone name (if zone is used by kalloc)
*/
snprintf(zone_name, MAX_ZONE_NAME, "%s%s", zone_heap_name(z), z->z_name);
/* zlog0 isn't allowed. */
for (int i = 1; i <= max_num_zones_to_log; i++) {
snprintf(zlog_name, MAX_ZONE_NAME, "zlog%d", i);
if (PE_parse_boot_argn(zlog_name, zlog_val, sizeof(zlog_val)) &&
track_this_zone(zone_name, zlog_val)) {
z->zone_logging = true;
num_zones_logged++;
break;
}
}
/*
* Backwards compat. with the old boot-arg used to specify single zone
* logging i.e. zlog Needs to happen after the newer zlogn checks
* because the prefix will match all the zlogn
* boot-args.
*/
if (!z->zone_logging &&
PE_parse_boot_argn("zlog", zlog_val, sizeof(zlog_val)) &&
track_this_zone(zone_name, zlog_val)) {
z->zone_logging = true;
num_zones_logged++;
}
/*
* If we want to log a zone, see if we need to allocate buffer space for
* the log.
*
* Some vm related zones are zinit'ed before we can do a kmem_alloc, so
* we have to defer allocation in that case.
*
* zone_init() will finish the job.
*
* If we want to log one of the VM related zones that's set up early on,
* we will skip allocation of the log until zinit is called again later
* on some other zone.
*/
if (z->zone_logging && startup_phase >= STARTUP_SUB_KMEM_ALLOC) {
zone_enable_logging(z);
}
}
/*
* Each record in the log contains a pointer to the zone element it refers to,
* and a small array to hold the pc's from the stack trace. A
* record is added to the log each time a zalloc() is done in the zone_of_interest. For leak debugging,
* the record is cleared when a zfree() is done. For corruption debugging, the log tracks both allocs and frees.
* If the log fills, old records are replaced as if it were a circular buffer.
*/
/*
* Decide if we want to log this zone by doing a string compare between a zone name and the name
* of the zone to log. Return true if the strings are equal, false otherwise. Because it's not
* possible to include spaces in strings passed in via the boot-args, a period in the logname will
* match a space in the zone name.
*/
/*
* Test if we want to log this zalloc/zfree event. We log if this is the zone we're interested in and
* the buffer for the records has been allocated.
*/
#define DO_LOGGING(z) (z->zlog_btlog != NULL)
#else /* !ZONE_ENABLE_LOGGING */
#define DO_LOGGING(z) 0
#endif /* !ZONE_ENABLE_LOGGING */
#if CONFIG_ZLEAKS
/*
* The zone leak detector, abbreviated 'zleak', keeps track of a subset of the currently outstanding
* allocations made by the zone allocator. Every zleak_sample_factor allocations in each zone, we capture a
* backtrace. Every free, we examine the table and determine if the allocation was being tracked,
* and stop tracking it if it was being tracked.
*
* We track the allocations in the zallocations hash table, which stores the address that was returned from
* the zone allocator. Each stored entry in the zallocations table points to an entry in the ztraces table, which
* stores the backtrace associated with that allocation. This provides uniquing for the relatively large
* backtraces - we don't store them more than once.
*
* Data collection begins when the zone map is 50% full, and only occurs for zones that are taking up
* a large amount of virtual space.
*/
#define ZLEAK_STATE_ENABLED 0x01 /* Zone leak monitoring should be turned on if zone_map fills up. */
#define ZLEAK_STATE_ACTIVE 0x02 /* We are actively collecting traces. */
#define ZLEAK_STATE_ACTIVATING 0x04 /* Some thread is doing setup; others should move along. */
#define ZLEAK_STATE_FAILED 0x08 /* Attempt to allocate tables failed. We will not try again. */
static uint32_t zleak_state = 0; /* State of collection, as above */
static unsigned int zleak_sample_factor = 1000; /* Allocations per sample attempt */
bool panic_include_ztrace = FALSE; /* Enable zleak logging on panic */
vm_size_t zleak_global_tracking_threshold; /* Size of zone map at which to start collecting data */
vm_size_t zleak_per_zone_tracking_threshold; /* Size a zone will have before we will collect data on it */
/*
* Counters for allocation statistics.
*/
/* Times two active records want to occupy the same spot */
static unsigned int z_alloc_collisions = 0;
static unsigned int z_trace_collisions = 0;
/* Times a new record lands on a spot previously occupied by a freed allocation */
static unsigned int z_alloc_overwrites = 0;
static unsigned int z_trace_overwrites = 0;
/* Times a new alloc or trace is put into the hash table */
static unsigned int z_alloc_recorded = 0;
static unsigned int z_trace_recorded = 0;
/* Times zleak_log returned false due to not being able to acquire the lock */
static unsigned int z_total_conflicts = 0;
/*
* Structure for keeping track of an allocation
* An allocation bucket is in use if its element is not NULL
*/
struct zallocation {
uintptr_t za_element; /* the element that was zalloc'ed or zfree'ed, NULL if bucket unused */
vm_size_t za_size; /* how much memory did this allocation take up? */
uint32_t za_trace_index; /* index into ztraces for backtrace associated with allocation */
/* TODO: #if this out */
uint32_t za_hit_count; /* for determining effectiveness of hash function */
};
/* Size must be a power of two for the zhash to be able to just mask off bits instead of mod */
static uint32_t zleak_alloc_buckets = CONFIG_ZLEAK_ALLOCATION_MAP_NUM;
static uint32_t zleak_trace_buckets = CONFIG_ZLEAK_TRACE_MAP_NUM;
vm_size_t zleak_max_zonemap_size;
/* Hashmaps of allocations and their corresponding traces */
static struct zallocation* zallocations;
static struct ztrace* ztraces;
/* not static so that panic can see this, see kern/debug.c */
struct ztrace* top_ztrace;
/* Lock to protect zallocations, ztraces, and top_ztrace from concurrent modification. */
static LCK_GRP_DECLARE(zleak_lock_grp, "zleak_lock");
static LCK_SPIN_DECLARE(zleak_lock, &zleak_lock_grp);
/*
* Initializes the zone leak monitor. Called from zone_init()
*/
__startup_func
static void
zleak_init(vm_size_t max_zonemap_size)
{
char scratch_buf[16];
boolean_t zleak_enable_flag = FALSE;
zleak_max_zonemap_size = max_zonemap_size;
zleak_global_tracking_threshold = max_zonemap_size / 2;
zleak_per_zone_tracking_threshold = zleak_global_tracking_threshold / 8;
#if CONFIG_EMBEDDED
if (PE_parse_boot_argn("-zleakon", scratch_buf, sizeof(scratch_buf))) {
zleak_enable_flag = TRUE;
printf("zone leak detection enabled\n");
} else {
zleak_enable_flag = FALSE;
printf("zone leak detection disabled\n");
}
#else /* CONFIG_EMBEDDED */
/* -zleakoff (flag to disable zone leak monitor) */
if (PE_parse_boot_argn("-zleakoff", scratch_buf, sizeof(scratch_buf))) {
zleak_enable_flag = FALSE;
printf("zone leak detection disabled\n");
} else {
zleak_enable_flag = TRUE;
printf("zone leak detection enabled\n");
}
#endif /* CONFIG_EMBEDDED */
/* zfactor=XXXX (override how often to sample the zone allocator) */
if (PE_parse_boot_argn("zfactor", &zleak_sample_factor, sizeof(zleak_sample_factor))) {
printf("Zone leak factor override: %u\n", zleak_sample_factor);
}
/* zleak-allocs=XXXX (override number of buckets in zallocations) */
if (PE_parse_boot_argn("zleak-allocs", &zleak_alloc_buckets, sizeof(zleak_alloc_buckets))) {
printf("Zone leak alloc buckets override: %u\n", zleak_alloc_buckets);
/* uses 'is power of 2' trick: (0x01000 & 0x00FFF == 0) */
if (zleak_alloc_buckets == 0 || (zleak_alloc_buckets & (zleak_alloc_buckets - 1))) {
printf("Override isn't a power of two, bad things might happen!\n");
}
}
/* zleak-traces=XXXX (override number of buckets in ztraces) */
if (PE_parse_boot_argn("zleak-traces", &zleak_trace_buckets, sizeof(zleak_trace_buckets))) {
printf("Zone leak trace buckets override: %u\n", zleak_trace_buckets);
/* uses 'is power of 2' trick: (0x01000 & 0x00FFF == 0) */
if (zleak_trace_buckets == 0 || (zleak_trace_buckets & (zleak_trace_buckets - 1))) {
printf("Override isn't a power of two, bad things might happen!\n");
}
}
if (zleak_enable_flag) {
zleak_state = ZLEAK_STATE_ENABLED;
}
}
/*
* Support for kern.zleak.active sysctl - a simplified
* version of the zleak_state variable.
*/
int
get_zleak_state(void)
{
if (zleak_state & ZLEAK_STATE_FAILED) {
return -1;
}
if (zleak_state & ZLEAK_STATE_ACTIVE) {
return 1;
}
return 0;
}
kern_return_t
zleak_activate(void)
{
kern_return_t retval;
vm_size_t z_alloc_size = zleak_alloc_buckets * sizeof(struct zallocation);
vm_size_t z_trace_size = zleak_trace_buckets * sizeof(struct ztrace);
void *allocations_ptr = NULL;
void *traces_ptr = NULL;
/* Only one thread attempts to activate at a time */
if (zleak_state & (ZLEAK_STATE_ACTIVE | ZLEAK_STATE_ACTIVATING | ZLEAK_STATE_FAILED)) {
return KERN_SUCCESS;
}
/* Indicate that we're doing the setup */
lck_spin_lock(&zleak_lock);
if (zleak_state & (ZLEAK_STATE_ACTIVE | ZLEAK_STATE_ACTIVATING | ZLEAK_STATE_FAILED)) {
lck_spin_unlock(&zleak_lock);
return KERN_SUCCESS;
}
zleak_state |= ZLEAK_STATE_ACTIVATING;
lck_spin_unlock(&zleak_lock);
/* Allocate and zero tables */
retval = kmem_alloc_kobject(kernel_map, (vm_offset_t*)&allocations_ptr, z_alloc_size, VM_KERN_MEMORY_DIAG);
if (retval != KERN_SUCCESS) {
goto fail;
}
retval = kmem_alloc_kobject(kernel_map, (vm_offset_t*)&traces_ptr, z_trace_size, VM_KERN_MEMORY_DIAG);
if (retval != KERN_SUCCESS) {
goto fail;
}
bzero(allocations_ptr, z_alloc_size);
bzero(traces_ptr, z_trace_size);
/* Everything's set. Install tables, mark active. */
zallocations = allocations_ptr;
ztraces = traces_ptr;
/*
* Initialize the top_ztrace to the first entry in ztraces,
* so we don't have to check for null in zleak_log
*/
top_ztrace = &ztraces[0];
/*
* Note that we do need a barrier between installing
* the tables and setting the active flag, because the zfree()
* path accesses the table without a lock if we're active.
*/
lck_spin_lock(&zleak_lock);
zleak_state |= ZLEAK_STATE_ACTIVE;
zleak_state &= ~ZLEAK_STATE_ACTIVATING;
lck_spin_unlock(&zleak_lock);
return 0;
fail:
/*
* If we fail to allocate memory, don't further tax
* the system by trying again.
*/
lck_spin_lock(&zleak_lock);
zleak_state |= ZLEAK_STATE_FAILED;
zleak_state &= ~ZLEAK_STATE_ACTIVATING;
lck_spin_unlock(&zleak_lock);
if (allocations_ptr != NULL) {
kmem_free(kernel_map, (vm_offset_t)allocations_ptr, z_alloc_size);
}
if (traces_ptr != NULL) {
kmem_free(kernel_map, (vm_offset_t)traces_ptr, z_trace_size);
}
return retval;
}
static inline void
zleak_activate_if_needed(void)
{
if (__probable((zleak_state & ZLEAK_STATE_ENABLED) == 0)) {
return;
}
if (zleak_state & ZLEAK_STATE_ACTIVE) {
return;
}
if (zone_submaps_approx_size() < zleak_global_tracking_threshold) {
return;
}
kern_return_t kr = zleak_activate();
if (kr != KERN_SUCCESS) {
printf("Failed to activate live zone leak debugging (%d).\n", kr);
}
}
static inline void
zleak_track_if_needed(zone_t z)
{
if (__improbable(zleak_state & ZLEAK_STATE_ACTIVE)) {
if (!z->zleak_on &&
zone_size_wired(z) >= zleak_per_zone_tracking_threshold) {
z->zleak_on = true;
}
}
}
/*
* TODO: What about allocations that never get deallocated,
* especially ones with unique backtraces? Should we wait to record
* until after boot has completed?
* (How many persistent zallocs are there?)
*/
/*
* This function records the allocation in the allocations table,
* and stores the associated backtrace in the traces table
* (or just increments the refcount if the trace is already recorded)
* If the allocation slot is in use, the old allocation is replaced with the new allocation, and
* the associated trace's refcount is decremented.
* If the trace slot is in use, it returns.
* The refcount is incremented by the amount of memory the allocation consumes.
* The return value indicates whether to try again next time.
*/
static boolean_t
zleak_log(uintptr_t* bt,
uintptr_t addr,
uint32_t depth,
vm_size_t allocation_size)
{
/* Quit if there's someone else modifying the hash tables */
if (!lck_spin_try_lock(&zleak_lock)) {
z_total_conflicts++;
return FALSE;
}
struct zallocation* allocation = &zallocations[hashaddr(addr, zleak_alloc_buckets)];
uint32_t trace_index = hashbacktrace(bt, depth, zleak_trace_buckets);
struct ztrace* trace = &ztraces[trace_index];
allocation->za_hit_count++;
trace->zt_hit_count++;
/*
* If the allocation bucket we want to be in is occupied, and if the occupier
* has the same trace as us, just bail.
*/
if (allocation->za_element != (uintptr_t) 0 && trace_index == allocation->za_trace_index) {
z_alloc_collisions++;
lck_spin_unlock(&zleak_lock);
return TRUE;
}
/* STEP 1: Store the backtrace in the traces array. */
/* A size of zero indicates that the trace bucket is free. */
if (trace->zt_size > 0 && bcmp(trace->zt_stack, bt, (depth * sizeof(uintptr_t))) != 0) {
/*
* Different unique trace with same hash!
* Just bail - if we're trying to record the leaker, hopefully the other trace will be deallocated
* and get out of the way for later chances
*/
trace->zt_collisions++;
z_trace_collisions++;
lck_spin_unlock(&zleak_lock);
return TRUE;
} else if (trace->zt_size > 0) {
/* Same trace, already added, so increment refcount */
trace->zt_size += allocation_size;
} else {
/* Found an unused trace bucket, record the trace here! */
if (trace->zt_depth != 0) { /* if this slot was previously used but not currently in use */
z_trace_overwrites++;
}
z_trace_recorded++;
trace->zt_size = allocation_size;
memcpy(trace->zt_stack, bt, (depth * sizeof(uintptr_t)));
trace->zt_depth = depth;
trace->zt_collisions = 0;
}
/* STEP 2: Store the allocation record in the allocations array. */
if (allocation->za_element != (uintptr_t) 0) {
/*
* Straight up replace any allocation record that was there. We don't want to do the work
* to preserve the allocation entries that were there, because we only record a subset of the
* allocations anyways.
*/
z_alloc_collisions++;
struct ztrace* associated_trace = &ztraces[allocation->za_trace_index];
/* Knock off old allocation's size, not the new allocation */
associated_trace->zt_size -= allocation->za_size;
} else if (allocation->za_trace_index != 0) {
/* Slot previously used but not currently in use */
z_alloc_overwrites++;
}
allocation->za_element = addr;
allocation->za_trace_index = trace_index;
allocation->za_size = allocation_size;
z_alloc_recorded++;
if (top_ztrace->zt_size < trace->zt_size) {
top_ztrace = trace;
}
lck_spin_unlock(&zleak_lock);
return TRUE;
}
/*
* Free the allocation record and release the stacktrace.
* This should be as fast as possible because it will be called for every free.
*/
__attribute__((noinline))
static void
zleak_free(uintptr_t addr,
vm_size_t allocation_size)
{
if (addr == (uintptr_t) 0) {
return;
}
struct zallocation* allocation = &zallocations[hashaddr(addr, zleak_alloc_buckets)];
/* Double-checked locking: check to find out if we're interested, lock, check to make
* sure it hasn't changed, then modify it, and release the lock.
*/
if (allocation->za_element == addr && allocation->za_trace_index < zleak_trace_buckets) {
/* if the allocation was the one, grab the lock, check again, then delete it */
lck_spin_lock(&zleak_lock);
if (allocation->za_element == addr && allocation->za_trace_index < zleak_trace_buckets) {
struct ztrace *trace;
/* allocation_size had better match what was passed into zleak_log - otherwise someone is freeing into the wrong zone! */
if (allocation->za_size != allocation_size) {
panic("Freeing as size %lu memory that was allocated with size %lu\n",
(uintptr_t)allocation_size, (uintptr_t)allocation->za_size);
}
trace = &ztraces[allocation->za_trace_index];
/* size of 0 indicates trace bucket is unused */
if (trace->zt_size > 0) {
trace->zt_size -= allocation_size;
}
/* A NULL element means the allocation bucket is unused */
allocation->za_element = 0;
}
lck_spin_unlock(&zleak_lock);
}
}
#else
static inline void
zleak_activate_if_needed(void)
{
}
static inline void
zleak_track_if_needed(__unused zone_t z)
{
}
#endif /* CONFIG_ZLEAKS */
#if ZONE_ENABLE_LOGGING || CONFIG_ZLEAKS
__attribute__((noinline))
static void
zalloc_log_or_trace_leaks(zone_t zone, vm_offset_t addr, void *fp)
{
uintptr_t zbt[MAX_ZTRACE_DEPTH]; /* used in zone leak logging and zone leak detection */
unsigned int numsaved = 0;
#if ZONE_ENABLE_LOGGING
if (DO_LOGGING(zone)) {
numsaved = backtrace(zbt, MAX_ZTRACE_DEPTH, NULL);
btlog_add_entry(zone->zlog_btlog, (void *)addr,
ZOP_ALLOC, (void **)zbt, numsaved);
}
#endif /* ZONE_ENABLE_LOGGING */
#if CONFIG_ZLEAKS
/*
* Zone leak detection: capture a backtrace every zleak_sample_factor
* allocations in this zone.
*/
if (__improbable(zone->zleak_on)) {
if (sample_counter(&zone->zleak_capture, zleak_sample_factor)) {
/* Avoid backtracing twice if zone logging is on */
if (numsaved == 0) {
numsaved = backtrace_frame(zbt, MAX_ZTRACE_DEPTH, fp, NULL);
}
/* Sampling can fail if another sample is happening at the same time in a different zone. */
if (!zleak_log(zbt, addr, numsaved, zone_elem_size(zone))) {
/* If it failed, roll back the counter so we sample the next allocation instead. */
zone->zleak_capture = zleak_sample_factor;
}
}
}
if (__improbable(zone_leaks_scan_enable &&
!(zone_elem_size(zone) & (sizeof(uintptr_t) - 1)))) {
unsigned int count, idx;
/* Fill element, from tail, with backtrace in reverse order */
if (numsaved == 0) {
numsaved = backtrace_frame(zbt, MAX_ZTRACE_DEPTH, fp, NULL);
}
count = (unsigned int)(zone_elem_size(zone) / sizeof(uintptr_t));
if (count >= numsaved) {
count = numsaved - 1;
}
for (idx = 0; idx < count; idx++) {
((uintptr_t *)addr)[count - 1 - idx] = zbt[idx + 1];
}
}
#endif /* CONFIG_ZLEAKS */
}
static inline bool
zalloc_should_log_or_trace_leaks(zone_t zone, vm_size_t elem_size)
{
#if ZONE_ENABLE_LOGGING
if (DO_LOGGING(zone)) {
return true;
}
#endif /* ZONE_ENABLE_LOGGING */
#if CONFIG_ZLEAKS
/*
* Zone leak detection: capture a backtrace every zleak_sample_factor
* allocations in this zone.
*/
if (zone->zleak_on) {
return true;
}
if (zone_leaks_scan_enable && !(elem_size & (sizeof(uintptr_t) - 1))) {
return true;
}
#endif /* CONFIG_ZLEAKS */
return false;
}
#endif /* ZONE_ENABLE_LOGGING || CONFIG_ZLEAKS */
#if ZONE_ENABLE_LOGGING
__attribute__((noinline))
static void
zfree_log_trace(zone_t zone, vm_offset_t addr, void *fp)
{
/*
* See if we're doing logging on this zone.
*
* There are two styles of logging used depending on
* whether we're trying to catch a leak or corruption.
*/
if (__improbable(DO_LOGGING(zone))) {
if (corruption_debug_flag) {
uintptr_t zbt[MAX_ZTRACE_DEPTH];
unsigned int numsaved;
/*
* We're logging to catch a corruption.
*
* Add a record of this zfree operation to log.
*/
numsaved = backtrace_frame(zbt, MAX_ZTRACE_DEPTH, fp, NULL);
btlog_add_entry(zone->zlog_btlog, (void *)addr, ZOP_FREE,
(void **)zbt, numsaved);
} else {
/*
* We're logging to catch a leak.
*
* Remove any record we might have for this element
* since it's being freed. Note that we may not find it
* if the buffer overflowed and that's OK.
*
* Since the log is of a limited size, old records get
* overwritten if there are more zallocs than zfrees.
*/
btlog_remove_entries_for_element(zone->zlog_btlog, (void *)addr);
}
}
}
#endif /* ZONE_ENABLE_LOGGING */
/* These functions outside of CONFIG_ZLEAKS because they are also used in
* mbuf.c for mbuf leak-detection. This is why they lack the z_ prefix.
*/
/* "Thomas Wang's 32/64 bit mix functions." http://www.concentric.net/~Ttwang/tech/inthash.htm */
uintptr_t
hash_mix(uintptr_t x)
{
#ifndef __LP64__
x += ~(x << 15);
x ^= (x >> 10);
x += (x << 3);
x ^= (x >> 6);
x += ~(x << 11);
x ^= (x >> 16);
#else
x += ~(x << 32);
x ^= (x >> 22);
x += ~(x << 13);
x ^= (x >> 8);
x += (x << 3);
x ^= (x >> 15);
x += ~(x << 27);
x ^= (x >> 31);
#endif
return x;
}
uint32_t
hashbacktrace(uintptr_t* bt, uint32_t depth, uint32_t max_size)
{
uintptr_t hash = 0;
uintptr_t mask = max_size - 1;
while (depth) {
hash += bt[--depth];
}
hash = hash_mix(hash) & mask;
assert(hash < max_size);
return (uint32_t) hash;
}
/*
* TODO: Determine how well distributed this is
* max_size must be a power of 2. i.e 0x10000 because 0x10000-1 is 0x0FFFF which is a great bitmask
*/
uint32_t
hashaddr(uintptr_t pt, uint32_t max_size)
{
uintptr_t hash = 0;
uintptr_t mask = max_size - 1;
hash = hash_mix(pt) & mask;
assert(hash < max_size);
return (uint32_t) hash;
}
#endif /* !ZALLOC_TEST */
#pragma mark zone (re)fill
#if !ZALLOC_TEST
/*!
* @defgroup Zone Refill
* @{
*
* @brief
* Functions handling The zone refill machinery.
*
* @discussion
* Zones are refilled based on 3 mechanisms: direct expansion, async expansion,
* VM-specific replenishment. Zones using VM-specific replenishment are marked
* with the @c z_replenishes property set.
*
* @c zalloc_ext() is the codepath that kicks the zone refill when the zone is
* dropping below half of its @c z_elems_rsv (0 for most zones) and will:
*
* - call @c zone_expand_locked() directly if the caller is allowed to block,
*
* - wakeup the asynchroous expansion thread call if the caller is not allowed
* to block.
*
* - call @c zone_replenish_locked() to kick the replenish state machine.
*
*
* <h2>Synchronous expansion</h2>
*
* This mechanism is actually the only one that may refill a zone, and all the
* other ones funnel through this one eventually.
*
* @c zone_expand_locked() implements the core of the expansion mechanism,
* and will do so while a caller specified predicate is true.
*
* Zone expansion allows for up to 2 threads to concurrently refill the zone:
* - one VM privileged thread,
* - one regular thread.
*
* Regular threads that refill will put down their identity in @c z_expander,
* so that priority inversion avoidance can be implemented.
*
* However, VM privileged threads are allowed to use VM page reserves,
* which allows for the system to recover from extreme memory pressure
* situations, allowing for the few allocations that @c zone_gc() or
* killing processes require.
*
* When a VM privileged thread is also expanding, the @c z_expander_vm_priv bit
* is set. @c z_expander is not necessarily the identity of this VM privileged
* thread (it is if the VM privileged thread came in first, but wouldn't be, and
* could even be @c THREAD_NULL otherwise).
*
* Note that the pageout-scan daemon might be BG and is VM privileged. To avoid
* spending a whole pointer on priority inheritance for VM privileged threads
* (and other issues related to having two owners), we use the rwlock boost as
* a stop gap to avoid priority inversions.
*
*
* <h2>Chunk wiring policies</h2>
*
* Zones allocate memory in chunks of @c zone_t::z_chunk_pages pages at a time
* to try to minimize fragmentation relative to element sizes not aligning with
* a chunk size well. However, this can grow large and be hard to fulfill on
* a system under a lot of memory pressure (chunks can be as long as 8 pages on
* 4k page systems).
*
* This is why, when under memory pressure the system allows chunks to be
* partially populated. The metadata of the first page in the chunk maintains
* the count of actually populated pages.
*
* The metadata for addresses assigned to a zone are found of 4 queues:
* - @c z_pageq_empty has chunk heads with populated pages and no allocated
* elements (those can be targeted by @c zone_gc()),
* - @c z_pageq_partial has chunk heads with populated pages that are partially
* used,
* - @c z_pageq_full has chunk heads with populated pages with no free elements
* left,
* - @c z_pageq_va has either chunk heads for sequestered VA space assigned to
* the zone forever (if @c z_va_sequester is enabled), or the first secondary
* metadata for a chunk whose corresponding page is not populated in the
* chunk.
*
* When new pages need to be wired/populated, chunks from the @c z_pageq_va
* queues are preferred.
*
*
* <h2>Asynchronous expansion</h2>
*
* This mechanism allows for refilling zones used mostly with non blocking
* callers. It relies on a thread call (@c zone_expand_callout) which will
* iterate all zones and refill the ones marked with @c z_async_refilling.
*
* NOTE: If the calling thread for zalloc_noblock is lower priority than
* the thread_call, then zalloc_noblock to an empty zone may succeed.
*
*
* <h2>Dealing with zone allocations from the mach VM code</h2>
*
* The implementation of the mach VM itself uses the zone allocator
* for things like the vm_map_entry data structure. In order to prevent
* an infinite recursion problem when adding more pages to a zone, @c zalloc
* uses a replenish thread to refill the VM layer's zones before they have
* too few remaining free entries. The reserved remaining free entries
* guarantee that the VM routines can get entries from already mapped pages.
*
* In order for that to work, the amount of allocations in the nested
* case have to be bounded. There are currently 2 replenish zones, and
* if each needs 1 element of each zone to add a new page to itself, that
* gives us a minumum reserve of 2 elements.
*
* There is also a deadlock issue with the zone garbage collection thread,
* or any thread that is trying to free zone pages. While holding
* the kernel's map lock they may need to allocate new VM map entries, hence
* we need enough reserve to allow them to get past the point of holding the
* map lock. After freeing that page, the GC thread will wait in
* @c zone_reclaim() until the replenish threads can finish.
* Since there's only 1 GC thread at a time, that adds a minimum of 1 to the
* reserve size.
*
* Since the minumum amount you can add to a zone is 1 page,
* we'll use 16K (from ARM) as the refill size on all platforms.
*
* When a refill zone drops to half that available, i.e. REFILL_SIZE / 2,
* @c zalloc_ext() will wake the replenish thread. The replenish thread runs
* until at least REFILL_SIZE worth of free elements exist, before sleeping again.
* In the meantime threads may continue to use the reserve until there are only
* REFILL_SIZE / 4 elements left. Below that point only the replenish threads
* themselves and the GC thread may continue to use from the reserve.
*/
static thread_call_data_t zone_expand_callout;
static inline kma_flags_t
zone_kma_flags(zone_t z, zalloc_flags_t flags)
{
kma_flags_t kmaflags = KMA_KOBJECT | KMA_ZERO;
if (z->z_noencrypt) {
kmaflags |= KMA_NOENCRYPT;
}
if (flags & Z_NOPAGEWAIT) {
kmaflags |= KMA_NOPAGEWAIT;
}
if (z->z_permanent || (!z->z_destructible && z->z_va_sequester)) {
kmaflags |= KMA_PERMANENT;
}
if (z->z_submap_idx == Z_SUBMAP_IDX_GENERAL &&
z->kalloc_heap != KHEAP_ID_NONE) {
kmaflags |= KMA_KHEAP;
}
return kmaflags;
}
/*!
* @function zcram_and_lock()
*
* @brief
* Prepare some memory for being usable for allocation purposes.
*
* @discussion
* Prepare memory in <code>[addr + ptoa(pg_start), addr + ptoa(pg_end))</code>
* to be usable in the zone.
*
* This function assumes the metadata is already populated for the range.
*
* Calling this function with @c pg_start being 0 means that the memory
* is either a partial chunk, or a full chunk, that isn't published anywhere
* and the initialization can happen without locks held.
*
* Calling this function with a non zero @c pg_start means that we are extending
* an existing chunk: the memory in <code>[addr, addr + ptoa(pg_start))</code>,
* is already usable and published in the zone, so extending it requires holding
* the zone lock.
*
* @param zone The zone to cram new populated pages into
* @param addr The base address for the chunk(s)
* @param pg_va_new The number of virtual pages newly assigned to the zone
* @param pg_start The first newly populated page relative to @a addr.
* @param pg_end The after-last newly populated page relative to @a addr.
* @param kind The kind of memory assigned to the zone.
*/
static void
zcram_and_lock(zone_t zone, vm_offset_t addr, uint32_t pg_va_new,
uint32_t pg_start, uint32_t pg_end, zone_addr_kind_t kind)
{
zone_id_t zindex = zone_index(zone);
vm_offset_t elem_size = zone_elem_size(zone);
uint32_t free_start = 0, free_end = 0;
struct zone_page_metadata *meta = zone_meta_from_addr(addr);
uint32_t chunk_pages = zone->z_chunk_pages;
assert(pg_start < pg_end && pg_end <= chunk_pages);
if (pg_start == 0) {
uint16_t chunk_len = (uint16_t)pg_end;
uint16_t secondary_len = ZM_SECONDARY_PAGE;
bool inline_bitmap = false;
if (zone->z_percpu) {
chunk_len = 1;
secondary_len = ZM_SECONDARY_PCPU_PAGE;
assert(pg_end == zpercpu_count());
}
if (!zone->z_permanent) {
inline_bitmap = zone->z_chunk_elems <= 32 * chunk_pages;
}
meta[0] = (struct zone_page_metadata){
.zm_index = zindex,
.zm_inline_bitmap = inline_bitmap,
.zm_chunk_len = chunk_len,
};
if (kind == ZONE_ADDR_FOREIGN) {
/* Never hit z_pageq_empty */
meta[0].zm_alloc_size = ZM_ALLOC_SIZE_LOCK;
}
for (uint16_t i = 1; i < chunk_pages; i++) {
meta[i] = (struct zone_page_metadata){
.zm_index = zindex,
.zm_inline_bitmap = inline_bitmap,
.zm_chunk_len = secondary_len,
.zm_page_index = i,
};
}
free_end = (uint32_t)ptoa(chunk_len) / elem_size;
if (!zone->z_permanent) {
zone_meta_bits_init(meta, free_end, zone->z_chunk_elems);
}
} else {
assert(!zone->z_percpu && !zone->z_permanent);
free_end = (uint32_t)ptoa(pg_end) / elem_size;
free_start = (uint32_t)ptoa(pg_start) / elem_size;
}
#if VM_MAX_TAG_ZONES
if (__improbable(zone->tags)) {
assert(kind == ZONE_ADDR_NATIVE && !zone->z_percpu);
ztMemoryAdd(zone, addr + ptoa(pg_start),
ptoa(pg_end - pg_start));
}
#endif /* VM_MAX_TAG_ZONES */
/*
* Insert the initialized pages / metadatas into the right lists.
*/
zone_lock(zone);
assert(zone->z_self == zone);
if (pg_start != 0) {
assert(meta->zm_chunk_len == pg_start);
zone_meta_bits_merge(meta, free_start, free_end);
meta->zm_chunk_len = (uint16_t)pg_end;
/*
* consume the zone_meta_lock_in_partial()
* done in zone_expand_locked()
*/
zone_meta_alloc_size_sub(zone, meta, ZM_ALLOC_SIZE_LOCK);
zone_meta_remqueue(zone, meta);
}
if (zone->z_permanent || meta->zm_alloc_size) {
zone_meta_queue_push(zone, &zone->z_pageq_partial, meta);
} else {
zone_meta_queue_push(zone, &zone->z_pageq_empty, meta);
zone->z_wired_empty += zone->z_percpu ? 1 : pg_end;
}
if (pg_end < chunk_pages) {
/* push any non populated residual VA on z_pageq_va */
zone_meta_queue_push(zone, &zone->z_pageq_va, meta + pg_end);
}
zone_elems_free_add(zone, free_end - free_start);
zone->z_elems_avail += free_end - free_start;
zone->z_wired_cur += zone->z_percpu ? 1 : pg_end - pg_start;
if (pg_va_new) {
zone->z_va_cur += zone->z_percpu ? 1 : pg_va_new;
}
if (zone->z_wired_hwm < zone->z_wired_cur) {
zone->z_wired_hwm = zone->z_wired_cur;
}
os_atomic_add(&zones_phys_page_mapped_count, pg_end - pg_start, relaxed);
}
static void
zcram(zone_t zone, vm_offset_t addr, uint32_t pages, zone_addr_kind_t kind)
{
uint32_t chunk_pages = zone->z_chunk_pages;
assert(pages % chunk_pages == 0);
for (; pages > 0; pages -= chunk_pages, addr += ptoa(chunk_pages)) {
zcram_and_lock(zone, addr, chunk_pages, 0, chunk_pages, kind);
zone_unlock(zone);
}
}
void
zone_cram_foreign(zone_t zone, vm_offset_t newmem, vm_size_t size)
{
uint32_t pages = (uint32_t)atop(size);
if (!from_zone_map(newmem, size, ZONE_ADDR_FOREIGN)) {
panic("zone_cram_foreign: foreign memory [%p] being crammed is "
"outside of expected range", (void *)newmem);
}
if (!zone->z_allows_foreign) {
panic("zone_cram_foreign: foreign memory [%p] being crammed in "
"zone '%s%s' not expecting it", (void *)newmem,
zone_heap_name(zone), zone_name(zone));
}
if (size % ptoa(zone->z_chunk_pages)) {
panic("zone_cram_foreign: foreign memory [%p] being crammed has "
"invalid size %zx", (void *)newmem, (size_t)size);
}
if (startup_phase >= STARTUP_SUB_ZALLOC) {
panic("zone_cram_foreign: foreign memory [%p] being crammed "
"after zalloc is initialized", (void *)newmem);
}
bzero((void *)newmem, size);
zcram(zone, newmem, pages, ZONE_ADDR_FOREIGN);
}
void
zone_fill_initially(zone_t zone, vm_size_t nelems)
{
kma_flags_t kmaflags;
kern_return_t kr;
vm_offset_t addr;
uint32_t pages;
assert(!zone->z_permanent && !zone->collectable && !zone->z_destructible);
assert(zone->z_elems_avail == 0);
kmaflags = zone_kma_flags(zone, Z_WAITOK) | KMA_PERMANENT;
pages = zone_alloc_pages_for_nelems(zone, nelems);
kr = kernel_memory_allocate(zone_submap(zone), &addr, ptoa(pages),
0, kmaflags, VM_KERN_MEMORY_ZONE);
if (kr != KERN_SUCCESS) {
panic("kernel_memory_allocate() of %u pages failed", pages);
}
zone_meta_populate(addr, ptoa(pages));
zcram(zone, addr, pages, ZONE_ADDR_NATIVE);
}
static vm_offset_t
zone_allocate_va(zone_t z, zalloc_flags_t flags)
{
kma_flags_t kmaflags = zone_kma_flags(z, flags) | KMA_VAONLY;
vm_size_t size = ptoa(z->z_chunk_pages);
kern_return_t kr;
vm_offset_t addr;
kr = kernel_memory_allocate(zone_submap(z), &addr, size, 0,
kmaflags, VM_KERN_MEMORY_ZONE);
#if !__LP64__
if (kr == KERN_NO_SPACE && z->z_replenishes) {
/*
* On 32bit the zone submaps do not have as much VA
* available, so use the VA reserved map for this
* purpose.
*/
vm_map_t map = zone_submaps[Z_SUBMAP_IDX_VA_RESERVE];
kr = kernel_memory_allocate(map, &addr, size, 0,
kmaflags, VM_KERN_MEMORY_ZONE);
}
#endif
if (kr == KERN_SUCCESS) {
#if ZALLOC_EARLY_GAPS
if (__improbable(zone_caching_disabled < 0)) {
zone_allocate_random_early_gap(z);
}
#endif /* ZALLOC_EARLY_GAPS */
zone_meta_populate(addr, size);
return addr;
}
panic_include_zprint = TRUE;
#if CONFIG_ZLEAKS
if ((zleak_state & ZLEAK_STATE_ACTIVE)) {
panic_include_ztrace = TRUE;
}
#endif /* CONFIG_ZLEAKS */
zone_t zone_largest = zone_find_largest();
panic("zalloc: zone map exhausted while allocating from zone [%s%s], "
"likely due to memory leak in zone [%s%s] "
"(%luM, %d elements allocated)",
zone_heap_name(z), zone_name(z),
zone_heap_name(zone_largest), zone_name(zone_largest),
(unsigned long)zone_size_wired(zone_largest) >> 20,
zone_count_allocated(zone_largest));
}
static bool
zone_expand_pred_nope(__unused zone_t z)
{
return false;
}
static inline void
ZONE_TRACE_VM_KERN_REQUEST_START(vm_size_t size)
{
#if DEBUG || DEVELOPMENT
VM_DEBUG_CONSTANT_EVENT(vm_kern_request, VM_KERN_REQUEST, DBG_FUNC_START,
size, 0, 0, 0);
#else
(void)size;
#endif
}
static inline void
ZONE_TRACE_VM_KERN_REQUEST_END(uint32_t pages)
{
#if DEBUG || DEVELOPMENT
task_t task = current_task();
if (pages && task) {
ledger_credit(task->ledger, task_ledgers.pages_grabbed_kern, pages);
}
VM_DEBUG_CONSTANT_EVENT(vm_kern_request, VM_KERN_REQUEST, DBG_FUNC_END,
pages, 0, 0, 0);
#else
(void)pages;
#endif
}
static void
zone_expand_locked(zone_t z, zalloc_flags_t flags, bool (*pred)(zone_t))
{
thread_t self = current_thread();
bool vm_priv = (self->options & TH_OPT_VMPRIV);
bool clear_vm_priv;
for (;;) {
if (!pred) {
/* NULL pred means "try just once" */
pred = zone_expand_pred_nope;
} else if (!pred(z)) {
return;
}
if (vm_priv && !z->z_expander_vm_priv) {
/*
* Claim the vm priv overcommit slot
*
* We do not track exact ownership for VM privileged
* threads, so use the rwlock boost as a stop-gap
* just in case.
*/
set_thread_rwlock_boost();
z->z_expander_vm_priv = true;
clear_vm_priv = true;
} else {
clear_vm_priv = false;
}
if (z->z_expander == NULL) {
z->z_expander = self;
break;
}
if (clear_vm_priv) {
break;
}
if (flags & Z_NOPAGEWAIT) {
return;
}
z->z_expanding_wait = true;
lck_spin_sleep_with_inheritor(&z->z_lock, LCK_SLEEP_DEFAULT,
&z->z_expander, z->z_expander,
TH_UNINT, TIMEOUT_WAIT_FOREVER);
}
do {
struct zone_page_metadata *meta = NULL;
uint32_t new_va = 0, cur_pages = 0, min_pages = 0, pages = 0;
vm_page_t page_list = NULL;
vm_offset_t addr = 0;
int waited = 0;
/*
* While we hold the zone lock, look if there's VA we can:
* - complete from partial pages,
* - reuse from the sequester list.
*
* When the page is being populated we pretend we allocated
* an extra element so that zone_gc() can't attempt to free
* the chunk (as it could become empty while we wait for pages).
*/
if (!zone_pva_is_null(z->z_pageq_va)) {
meta = zone_meta_queue_pop_native(z,
&z->z_pageq_va, &addr);
if (meta->zm_chunk_len == ZM_SECONDARY_PAGE) {
cur_pages = meta->zm_page_index;
meta -= cur_pages;
addr -= ptoa(cur_pages);
zone_meta_lock_in_partial(z, meta, cur_pages);
}
}
zone_unlock(z);
/*
* Do the zone leak activation here because zleak_activate()
* may block, and can't be done on the way out.
*
* Trigger jetsams via the vm_pageout_garbage_collect thread if
* we're running out of zone memory
*/
zleak_activate_if_needed();
if (zone_map_nearing_exhaustion()) {
thread_wakeup((event_t)&vm_pageout_garbage_collect);
}
/*
* And now allocate pages to populate our VA.
*/
if (z->z_percpu) {
min_pages = z->z_chunk_pages;
} else {
min_pages = (uint32_t)atop(round_page(zone_elem_size(z)));
}
ZONE_TRACE_VM_KERN_REQUEST_START(ptoa(z->z_chunk_pages - cur_pages));
while (pages < z->z_chunk_pages - cur_pages) {
vm_page_t m = vm_page_grab();
if (m) {
pages++;
m->vmp_snext = page_list;
page_list = m;
vm_page_zero_fill(m);
continue;
}
if (pages >= min_pages && (vm_pool_low() || waited)) {
break;
}
if ((flags & Z_NOPAGEWAIT) == 0) {
waited++;
VM_PAGE_WAIT();
continue;
}
/*
* Undo everything and bail out:
*
* - free pages
* - undo the fake allocation if any
* - put the VA back on the VA page queue.
*/
vm_page_free_list(page_list, FALSE);
ZONE_TRACE_VM_KERN_REQUEST_END(pages);
zone_lock(z);
if (cur_pages) {
zone_meta_unlock_from_partial(z, meta, cur_pages);
}
if (meta) {
zone_meta_queue_push(z, &z->z_pageq_va,
meta + cur_pages);
}
goto page_shortage;
}
/*
* If we didn't find pre-allocated VA, then allocate a chunk
* of VA here.
*/
if (addr == 0) {
addr = zone_allocate_va(z, flags);
meta = zone_meta_from_addr(addr);
new_va = z->z_chunk_pages;
}
kernel_memory_populate_with_pages(zone_submap(z),
addr + ptoa(cur_pages), ptoa(pages), page_list,
zone_kma_flags(z, flags), VM_KERN_MEMORY_ZONE);
ZONE_TRACE_VM_KERN_REQUEST_END(pages);
zcram_and_lock(z, addr, new_va, cur_pages, cur_pages + pages,
ZONE_ADDR_NATIVE);
} while (pred(z));
page_shortage:
zleak_track_if_needed(z);
if (clear_vm_priv) {
z->z_expander_vm_priv = false;
clear_thread_rwlock_boost();
}
if (z->z_expander == self) {
z->z_expander = THREAD_NULL;
}
if (z->z_expanding_wait) {
z->z_expanding_wait = false;
wakeup_all_with_inheritor(&z->z_expander, THREAD_AWAKENED);
}
}
static bool
zalloc_needs_refill(zone_t zone)
{
if (zone->z_elems_free > zone->z_elems_rsv) {
return false;
}
if (zone->z_wired_cur < zone->z_wired_max) {
return true;
}
if (zone->exhaustible) {
return false;
}
if (zone->expandable) {
/*
* If we're expandable, just don't go through this again.
*/
zone->z_wired_max = ~0u;
return true;
}
zone_unlock(zone);
panic_include_zprint = true;
#if CONFIG_ZLEAKS
if (zleak_state & ZLEAK_STATE_ACTIVE) {
panic_include_ztrace = true;
}
#endif /* CONFIG_ZLEAKS */
panic("zone '%s%s' exhausted", zone_heap_name(zone), zone_name(zone));
}
static void
zone_expand_async(__unused thread_call_param_t p0, __unused thread_call_param_t p1)
{
zone_foreach(z) {
if (z->no_callout) {
/* z_async_refilling will never be set */
continue;
}
if (z->z_replenishes) {
/* those use the zone_replenish_thread */
continue;
}
zone_lock(z);
if (z->z_self && z->z_async_refilling) {
z->z_async_refilling = false;
zone_expand_locked(z, Z_WAITOK, zalloc_needs_refill);
}
zone_unlock(z);
}
}
static inline void
zone_expand_async_schedule_if_needed(zone_t zone)
{
if (zone->z_elems_free > zone->z_elems_rsv || zone->z_async_refilling ||
zone->no_callout) {
return;
}
if (!zone->expandable && zone->z_wired_cur >= zone->z_wired_max) {
return;
}
if (zone->z_elems_free == 0 || !vm_pool_low()) {
zone->z_async_refilling = true;
thread_call_enter(&zone_expand_callout);
}
}
#endif /* !ZALLOC_TEST */
#pragma mark zone replenishing (VM allocations)
#if !ZALLOC_TEST
/*
* Tracks how many zone_replenish threads are active, because zone_gc() wants
* for those to be finished before it proceeds.
*
* This counts how many replenish threads are active in
* ZONE_REPLENISH_ACTIVE_INC increments,
* and uses the low bit to track if there are any waiters.
*/
#define ZONE_REPLENISH_ACTIVE_NONE 0u
#define ZONE_REPLENISH_ACTIVE_WAITER_BIT 1u
#define ZONE_REPLENISH_ACTIVE_INC 2u
#define ZONE_REPLENISH_ACTIVE_MASK (~ZONE_REPLENISH_ACTIVE_WAITER_BIT)
static unsigned _Atomic zone_replenish_active;
static unsigned zone_replenish_wakeups;
static unsigned zone_replenish_wakeups_initiated;
static unsigned zone_replenish_throttle_count;
#define ZONE_REPLENISH_TARGET (16 * 1024)
static void
zone_replenish_wait_if_needed(void)
{
/*
* This check can be racy, the reserves ought to be enough
* to compensate for a little race
*/
while (os_atomic_load(&zone_replenish_active, relaxed) !=
ZONE_REPLENISH_ACTIVE_NONE) {
unsigned o_active, n_active;
assert_wait(&zone_replenish_active, THREAD_UNINT);
os_atomic_rmw_loop(&zone_replenish_active, o_active, n_active, relaxed, {
if (o_active == ZONE_REPLENISH_ACTIVE_NONE) {
os_atomic_rmw_loop_give_up({
clear_wait(current_thread(), THREAD_AWAKENED);
return;
});
}
if (o_active & ZONE_REPLENISH_ACTIVE_WAITER_BIT) {
os_atomic_rmw_loop_give_up(break);
}
n_active = o_active | ZONE_REPLENISH_ACTIVE_WAITER_BIT;
});
thread_block(THREAD_CONTINUE_NULL);
}
}
__attribute__((noinline))
static void
zone_replenish_locked(zone_t zone)
{
thread_t thr = current_thread();
uint32_t min_free;
zone_replenish_wakeups++;
/*
* We'll let threads continue to allocate under the reserve:
* - until it depleted to 50% for regular threads,
* - until it depleted to 25% for VM_PRIV threads.
*
* After that only TH_OPT_ZONE_PRIV threads may continue.
*/
if (thr->options & TH_OPT_VMPRIV) {
min_free = zone->z_elems_rsv / 4;
} else {
min_free = zone->z_elems_rsv / 2;
}
while (zone->z_elems_free <= zone->z_elems_rsv) {
/*
* Wakeup the replenish thread if not running.
*/
if (!zone->z_async_refilling) {
os_atomic_add(&zone_replenish_active,
ZONE_REPLENISH_ACTIVE_INC, relaxed);
zone->z_async_refilling = true;
zone_replenish_wakeups_initiated++;
thread_wakeup(&zone->z_elems_rsv);
}
if (zone->z_elems_free > min_free) {
break;
}
/*
* TH_OPT_ZONE_PRIV threads are the GC thread and a replenish
* thread itself.
*
* Replenish threads *need* to use the reserve. GC threads need
* to get through the current allocation, but then will wait at
* a higher level after they've dropped any locks which would
* deadlock the replenish thread.
*
* The value of (refill_level / 2) in the previous bit of code
* should have given us headroom even though this thread didn't
* wait.
*/
if (thr->options & TH_OPT_ZONE_PRIV) {
assert(zone->z_elems_free != 0);
break;
}
if (startup_phase < STARTUP_SUB_MACH_IPC) {
panic("vm_map_steal_memory didn't steal enough memory: "
"trying to grow [%s%s] before the scheduler has started",
zone_heap_name(zone), zone_name(zone));
}
/*
* Wait for the replenish threads to add more elements
* for us to allocate from.
*/
zone_replenish_throttle_count++;
zone->z_replenish_wait = true;
assert_wait_timeout(zone, THREAD_UNINT, 1, NSEC_PER_MSEC);
zone_unlock(zone);
thread_block(THREAD_CONTINUE_NULL);
zone_lock(zone);
zone->z_replenish_wait = false;
assert(zone->z_self == zone);
}
}
static bool
zone_replenish_needed(zone_t z)
{
return z->z_elems_free <= z->z_elems_rsv;
}
/*
* High priority VM privileged thread used to asynchronously refill a given zone.
* These are needed for data structures used by the lower level VM itself. The
* replenish thread maintains a reserve of elements, so that the VM will never
* block in the zone allocator.
*/
__dead2
static void
zone_replenish_thread(void *_z, wait_result_t __unused wr)
{
unsigned o_active, n_active;
zone_t z = _z;
zone_lock(z);
assert(z->z_self == z);
assert(z->z_async_refilling && z->z_replenishes);
zone_expand_locked(z, Z_WAITOK, zone_replenish_needed);
if (z->z_replenish_wait) {
/* Wakeup any potentially throttled allocations */
z->z_replenish_wait = false;
thread_wakeup(z);
}
/* wakeup zone_reclaim() callers that were possibly waiting */
os_atomic_rmw_loop(&zone_replenish_active, o_active, n_active, relaxed, {
if (os_sub_overflow(o_active, ZONE_REPLENISH_ACTIVE_INC, &n_active)) {
panic("zone_replenish_active corrupt: %d", o_active);
}
if ((n_active & ZONE_REPLENISH_ACTIVE_MASK) == 0) {
n_active = ZONE_REPLENISH_ACTIVE_NONE;
}
});
if (n_active == ZONE_REPLENISH_ACTIVE_NONE &&
(o_active & ZONE_REPLENISH_ACTIVE_WAITER_BIT)) {
thread_wakeup(&zone_replenish_active);
}
z->z_async_refilling = false;
assert_wait(&z->z_elems_rsv, THREAD_UNINT);
zone_unlock(z);
thread_block_parameter(zone_replenish_thread, z);
__builtin_unreachable();
}
void
zone_replenish_configure(zone_t z)
{
thread_t th;
kern_return_t kr;
char name[MAXTHREADNAMESIZE];
zone_lock(z);
assert(!z->z_replenishes && !z->z_destructible);
z->z_elems_rsv = (uint16_t)(ZONE_REPLENISH_TARGET / zone_elem_size(z));
z->z_replenishes = true;
os_atomic_add(&zone_replenish_active, ZONE_REPLENISH_ACTIVE_INC, relaxed);
z->z_async_refilling = true;
zone_unlock(z);
kr = kernel_thread_create(zone_replenish_thread, z, MAXPRI_KERNEL, &th);
if (kr != KERN_SUCCESS) {
panic("zone_replenish_configure, thread create: 0x%x", kr);
}
/* make sure this thread can't lose its stack */
assert(th->reserved_stack == th->kernel_stack);
snprintf(name, sizeof(name), "z_replenish(%s)", zone_name(z));
thread_set_thread_name(th, name);
thread_mtx_lock(th);
th->options |= TH_OPT_VMPRIV | TH_OPT_ZONE_PRIV;
thread_start(th);
thread_mtx_unlock(th);
thread_deallocate(th);
}
/*! @} */
#endif /* !ZALLOC_TEST */
#pragma mark zone jetsam integration
#if !ZALLOC_TEST
/*
* We're being very conservative here and picking a value of 95%. We might need to lower this if
* we find that we're not catching the problem and are still hitting zone map exhaustion panics.
*/
#define ZONE_MAP_JETSAM_LIMIT_DEFAULT 95
/*
* Trigger zone-map-exhaustion jetsams if the zone map is X% full, where X=zone_map_jetsam_limit.
* Can be set via boot-arg "zone_map_jetsam_limit". Set to 95% by default.
*/
TUNABLE_WRITEABLE(unsigned int, zone_map_jetsam_limit, "zone_map_jetsam_limit",
ZONE_MAP_JETSAM_LIMIT_DEFAULT);
void
get_zone_map_size(uint64_t *current_size, uint64_t *capacity)
{
vm_offset_t phys_pages = os_atomic_load(&zones_phys_page_mapped_count, relaxed);
*current_size = ptoa_64(phys_pages);
*capacity = ptoa_64(zone_phys_mapped_max_pages);
}
void
get_largest_zone_info(char *zone_name, size_t zone_name_len, uint64_t *zone_size)
{
zone_t largest_zone = zone_find_largest();
/*
* Append kalloc heap name to zone name (if zone is used by kalloc)
*/
snprintf(zone_name, zone_name_len, "%s%s",
zone_heap_name(largest_zone), largest_zone->z_name);
*zone_size = zone_size_wired(largest_zone);
}
bool
zone_map_nearing_exhaustion(void)
{
uint64_t phys_pages = os_atomic_load(&zones_phys_page_mapped_count, relaxed);
return phys_pages * 100 > zone_phys_mapped_max_pages * zone_map_jetsam_limit;
}
#define VMENTRY_TO_VMOBJECT_COMPARISON_RATIO 98
/*
* Tries to kill a single process if it can attribute one to the largest zone. If not, wakes up the memorystatus thread
* to walk through the jetsam priority bands and kill processes.
*/
static void
kill_process_in_largest_zone(void)
{
pid_t pid = -1;
zone_t largest_zone = zone_find_largest();
printf("zone_map_exhaustion: Zone mapped %lld of %lld, used %lld, capacity %lld [jetsam limit %d%%]\n",
ptoa_64(os_atomic_load(&zones_phys_page_mapped_count, relaxed)),
ptoa_64(zone_phys_mapped_max_pages),
(uint64_t)zone_submaps_approx_size(),
(uint64_t)(zone_foreign_size() + zone_native_size()),
zone_map_jetsam_limit);
printf("zone_map_exhaustion: Largest zone %s%s, size %lu\n", zone_heap_name(largest_zone),
largest_zone->z_name, (uintptr_t)zone_size_wired(largest_zone));
/*
* We want to make sure we don't call this function from userspace.
* Or we could end up trying to synchronously kill the process
* whose context we're in, causing the system to hang.
*/
assert(current_task() == kernel_task);
/*
* If vm_object_zone is the largest, check to see if the number of
* elements in vm_map_entry_zone is comparable.
*
* If so, consider vm_map_entry_zone as the largest. This lets us target
* a specific process to jetsam to quickly recover from the zone map
* bloat.
*/
if (largest_zone == vm_object_zone) {
unsigned int vm_object_zone_count = zone_count_allocated(vm_object_zone);
unsigned int vm_map_entry_zone_count = zone_count_allocated(vm_map_entry_zone);
/* Is the VM map entries zone count >= 98% of the VM objects zone count? */
if (vm_map_entry_zone_count >= ((vm_object_zone_count * VMENTRY_TO_VMOBJECT_COMPARISON_RATIO) / 100)) {
largest_zone = vm_map_entry_zone;
printf("zone_map_exhaustion: Picking VM map entries as the zone to target, size %lu\n",
(uintptr_t)zone_size_wired(largest_zone));
}
}
/* TODO: Extend this to check for the largest process in other zones as well. */
if (largest_zone == vm_map_entry_zone) {
pid = find_largest_process_vm_map_entries();
} else {
printf("zone_map_exhaustion: Nothing to do for the largest zone [%s%s]. "
"Waking up memorystatus thread.\n", zone_heap_name(largest_zone),
largest_zone->z_name);
}
if (!memorystatus_kill_on_zone_map_exhaustion(pid)) {
printf("zone_map_exhaustion: Call to memorystatus failed, victim pid: %d\n", pid);
}
}
#endif /* !ZALLOC_TEST */
#pragma mark zfree
#if !ZALLOC_TEST
#if KASAN_ZALLOC
/*!
* @defgroup zfree
* @{
*
* @brief
* The codepath for zone frees.
*
* @discussion
* There are 4 major ways to allocate memory that end up in the zone allocator:
* - @c zfree()
* - @c zfree_percpu()
* - @c kfree*()
* - @c zfree_permanent()
*
* While permanent zones have their own allocation scheme, all other codepaths
* will eventually go through the @c zfree_ext() choking point.
*
* Ignoring the @c gzalloc_free() codepath, the decision tree looks like this:
* <code>
* zfree_ext()
* ├───> zfree_cached() ────────────────╮
* │ │ │
* │ │ │
* │ ├───> zfree_cached_slow() ───┤
* │ │ │ │
* │ │ v │
* ╰───────┴───> zfree_item() ──────────┴───>
* </code>
*
* @c zfree_ext() takes care of all the generic work to perform on an element
* before it is freed (zeroing, logging, tagging, ...) then will hand it off to:
* - @c zfree_item() if zone caching is off
* - @c zfree_cached() if zone caching is on.
*
* @c zfree_cached can take a number of decisions:
* - a fast path if the (f) or (a) magazines have space (preemption disabled),
* - using the cpu local or recirculation depot calling @c zfree_cached_slow(),
* - falling back to @c zfree_item() when CPU caching has been disabled.
*/
/*
* Called from zfree() to add the element being freed to the KASan quarantine.
*
* Returns true if the newly-freed element made it into the quarantine without
* displacing another, false otherwise. In the latter case, addrp points to the
* address of the displaced element, which will be freed by the zone.
*/
static bool
kasan_quarantine_freed_element(
zone_t *zonep, /* the zone the element is being freed to */
void **addrp) /* address of the element being freed */
{
zone_t zone = *zonep;
void *addr = *addrp;
/*
* Resize back to the real allocation size and hand off to the KASan
* quarantine. `addr` may then point to a different allocation, if the
* current element replaced another in the quarantine. The zone then
* takes ownership of the swapped out free element.
*/
vm_size_t usersz = zone_elem_size(zone) - 2 * zone->z_kasan_redzone;
vm_size_t sz = usersz;
if (addr && zone->z_kasan_redzone) {
kasan_check_free((vm_address_t)addr, usersz, KASAN_HEAP_ZALLOC);
addr = (void *)kasan_dealloc((vm_address_t)addr, &sz);
assert(sz == zone_elem_size(zone));
}
if (addr && !zone->kasan_noquarantine) {
kasan_free(&addr, &sz, KASAN_HEAP_ZALLOC, zonep, usersz, true);
if (!addr) {
return TRUE;
}
}
if (addr && zone->kasan_noquarantine) {
kasan_unpoison(addr, zone_elem_size(zone));
}
*addrp = addr;
return FALSE;
}
#endif /* KASAN_ZALLOC */
__header_always_inline void
zfree_drop(zone_t zone, struct zone_page_metadata *meta, zone_element_t ze,
bool recirc)
{
vm_offset_t esize = zone_elem_size(zone);
if (zone_meta_mark_free(meta, ze) == recirc) {
zone_meta_double_free_panic(zone, ze, __func__);
}
vm_offset_t old_size = meta->zm_alloc_size;
vm_offset_t max_size = ptoa(meta->zm_chunk_len) + ZM_ALLOC_SIZE_LOCK;
vm_offset_t new_size = zone_meta_alloc_size_sub(zone, meta, esize);
if (new_size == 0) {
/* whether the page was on the intermediate or all_used, queue, move it to free */
zone_meta_requeue(zone, &zone->z_pageq_empty, meta);
zone->z_wired_empty += meta->zm_chunk_len;
} else if (old_size + esize > max_size) {
/* first free element on page, move from all_used */
zone_meta_requeue(zone, &zone->z_pageq_partial, meta);
}
}
static void
zfree_item(zone_t zone, struct zone_page_metadata *meta, zone_element_t ze)
{
/* transfer preemption count to lock */
zone_lock_nopreempt_check_contention(zone, NULL);
zfree_drop(zone, meta, ze, false);
zone_elems_free_add(zone, 1);
zone_unlock(zone);
}
__attribute__((noinline))
static void
zfree_cached_slow(zone_t zone, struct zone_page_metadata *meta,
zone_element_t ze, zone_cache_t cache)
{
struct zone_depot mags = STAILQ_HEAD_INITIALIZER(mags);
zone_magazine_t mag = NULL;
uint16_t n = 0;
if (zone_meta_is_free(meta, ze)) {
zone_meta_double_free_panic(zone, ze, __func__);
}
if (zone == zc_magazine_zone) {
mag = (zone_magazine_t)zone_element_addr(ze,
zone_elem_size(zone));
#if KASAN_ZALLOC
kasan_poison_range((vm_offset_t)mag, zone_elem_size(zone),
ASAN_VALID);
#endif
} else {
mag = zone_magazine_alloc(Z_NOWAIT);
if (__improbable(mag == NULL)) {
return zfree_item(zone, meta, ze);
}
mag->zm_cur = 1;
mag->zm_elems[0] = ze;
}
mag = zone_magazine_replace(&cache->zc_free_cur,
&cache->zc_free_elems, mag);
z_debug_assert(cache->zc_free_cur <= 1);
z_debug_assert(mag->zm_cur == zc_mag_size());
STAILQ_INSERT_HEAD(&mags, mag, zm_link);
n = 1;
if (cache->zc_depot_max >= 2 * zc_mag_size()) {
/*
* If we can use the local depot (zc_depot_max allows for
* 2 magazines worth of elements) then:
*
* 1. if we have space for an extra depot locally,
* push it, and leave.
*
* 2. if we overflow, then take (1 / zc_recirc_denom)
* of the depot out, in order to migrate it to the
* recirculation depot.
*/
zone_depot_lock_nopreempt(cache);
if ((cache->zc_depot_cur + 2) * zc_mag_size() <=
cache->zc_depot_max) {
cache->zc_depot_cur++;
STAILQ_INSERT_TAIL(&cache->zc_depot, mag, zm_link);
return zone_depot_unlock(cache);
}
while (zc_recirc_denom * cache->zc_depot_cur * zc_mag_size() >=
(zc_recirc_denom - 1) * cache->zc_depot_max) {
mag = STAILQ_FIRST(&cache->zc_depot);
STAILQ_REMOVE_HEAD(&cache->zc_depot, zm_link);
STAILQ_INSERT_TAIL(&mags, mag, zm_link);
cache->zc_depot_cur--;
n++;
}
zone_depot_unlock(cache);
} else {
enable_preemption();
}
/*
* Preflight validity of all the elements before we touch the zone
* metadata, and then insert them into the recirculation depot.
*/
STAILQ_FOREACH(mag, &mags, zm_link) {
for (uint16_t i = 0; i < zc_mag_size(); i++) {
zone_element_validate(zone, mag->zm_elems[i]);
}
}
zone_lock_check_contention(zone, cache);
STAILQ_FOREACH(mag, &mags, zm_link) {
for (uint16_t i = 0; i < zc_mag_size(); i++) {
zone_element_t e = mag->zm_elems[i];
if (!zone_meta_mark_free(zone_meta_from_element(e), e)) {
zone_meta_double_free_panic(zone, e, __func__);
}
}
}
STAILQ_CONCAT(&zone->z_recirc, &mags);
zone->z_recirc_cur += n;
zone_elems_free_add(zone, n * zc_mag_size());
zone_unlock(zone);
}
static void
zfree_cached(zone_t zone, struct zone_page_metadata *meta, zone_element_t ze)
{
zone_cache_t cache = zpercpu_get(zone->z_pcpu_cache);
if (cache->zc_free_cur >= zc_mag_size()) {
if (cache->zc_alloc_cur >= zc_mag_size()) {
return zfree_cached_slow(zone, meta, ze, cache);
}
zone_cache_swap_magazines(cache);
}
if (__improbable(cache->zc_alloc_elems == NULL)) {
return zfree_item(zone, meta, ze);
}
if (zone_meta_is_free(meta, ze)) {
zone_meta_double_free_panic(zone, ze, __func__);
}
uint16_t idx = cache->zc_free_cur++;
if (idx >= zc_mag_size()) {
zone_accounting_panic(zone, "zc_free_cur overflow");
}
cache->zc_free_elems[idx] = ze;
enable_preemption();
}
/*
* The function is noinline when zlog can be used so that the backtracing can
* reliably skip the zfree_ext() and zfree_log_trace()
* boring frames.
*/
#if ZONE_ENABLE_LOGGING
__attribute__((noinline))
#endif /* ZONE_ENABLE_LOGGING */
void
zfree_ext(zone_t zone, zone_stats_t zstats, void *addr)
{
struct zone_page_metadata *page_meta;
vm_offset_t elem = (vm_offset_t)addr;
vm_size_t elem_size = zone_elem_size(zone);
zone_element_t ze;
DTRACE_VM2(zfree, zone_t, zone, void*, addr);
TRACE_MACHLEAKS(ZFREE_CODE, ZFREE_CODE_2, elem_size, elem);
#if VM_MAX_TAG_ZONES
if (__improbable(zone->tags)) {
vm_tag_t tag = *ztSlot(zone, elem) >> 1;
// set the tag with b0 clear so the block remains inuse
*ztSlot(zone, elem) = 0xFFFE;
vm_tag_update_zone_size(tag, zone->tag_zone_index,
-(long)elem_size);
}
#endif /* VM_MAX_TAG_ZONES */
#if KASAN_ZALLOC
if (kasan_quarantine_freed_element(&zone, &addr)) {
return;
}
/*
* kasan_quarantine_freed_element() might return a different
* {zone, addr} than the one being freed for kalloc heaps.
*
* Make sure we reload everything.
*/
elem = (vm_offset_t)addr;
elem_size = zone_elem_size(zone);
#endif
#if CONFIG_ZLEAKS
/*
* Zone leak detection: un-track the allocation
*/
if (__improbable(zone->zleak_on)) {
zleak_free(elem, elem_size);
}
#endif /* CONFIG_ZLEAKS */
#if ZONE_ENABLE_LOGGING
if (__improbable(DO_LOGGING(zone))) {
zfree_log_trace(zone, elem, __builtin_frame_address(0));
}
#endif /* ZONE_ENABLE_LOGGING */
#if CONFIG_GZALLOC
if (__improbable(zone->gzalloc_tracked)) {
return gzalloc_free(zone, zstats, addr);
}
#endif /* CONFIG_GZALLOC */
page_meta = zone_element_resolve(zone, elem, elem_size, &ze);
ze.ze_value |= zfree_clear_or_poison(zone, elem, elem_size);
#if KASAN_ZALLOC
if (zone->z_percpu) {
zpercpu_foreach_cpu(i) {
kasan_poison_range(elem + ptoa(i), elem_size,
ASAN_HEAP_FREED);
}
} else {
kasan_poison_range(elem, elem_size, ASAN_HEAP_FREED);
}
#endif
disable_preemption();
zpercpu_get(zstats)->zs_mem_freed += elem_size;
if (zone->z_pcpu_cache) {
return zfree_cached(zone, page_meta, ze);
}
return zfree_item(zone, page_meta, ze);
}
void
(zfree)(union zone_or_view zov, void *addr)
{
zone_t zone = zov.zov_view->zv_zone;
zone_stats_t zstats = zov.zov_view->zv_stats;
assert(!zone->z_percpu);
zfree_ext(zone, zstats, addr);
}
void
zfree_percpu(union zone_or_view zov, void *addr)
{
zone_t zone = zov.zov_view->zv_zone;
zone_stats_t zstats = zov.zov_view->zv_stats;
assert(zone->z_percpu);
zfree_ext(zone, zstats, (void *)__zpcpu_demangle(addr));
}
/*! @} */
#endif /* !ZALLOC_TEST */
#pragma mark zalloc
#if !ZALLOC_TEST
/*!
* @defgroup zalloc
* @{
*
* @brief
* The codepath for zone allocations.
*
* @discussion
* There are 4 major ways to allocate memory that end up in the zone allocator:
* - @c zalloc(), @c zalloc_flags(), ...
* - @c zalloc_percpu()
* - @c kalloc*()
* - @c zalloc_permanent()
*
* While permanent zones have their own allocation scheme, all other codepaths
* will eventually go through the @c zalloc_ext() choking point.
*
* Ignoring the @c zalloc_gz() codepath, the decision tree looks like this:
* <code>
* zalloc_ext()
* │
* ├───> zalloc_cached() ──────> zalloc_cached_fast() ───╮
* │ │ ^ │
* │ │ │ │
* │ ╰───> zalloc_cached_slow() ───╯ │
* │ │ │
* │<─────────────────╮ ├─────────────╮ │
* │ │ │ │ │
* │ │ v │ │
* │<───────╮ ╭──> zalloc_item_slow() ────┤ │
* │ │ │ │ │
* │ │ │ v │
* ╰───> zalloc_item() ──────────> zalloc_item_fast() ───┤
* │
* v
* zalloc_return()
* </code>
*
*
* The @c zalloc_item() track is used when zone caching is off:
* - @c zalloc_item_fast() is used when there are enough elements available,
* - @c zalloc_item_slow() is used when a refill is needed, which can cause
* the zone to grow. This is the only codepath that refills.
*
* This track uses the zone lock for serialization:
* - taken in @c zalloc_item(),
* - maintained during @c zalloc_item_slow() (possibly dropped and re-taken),
* - dropped in @c zalloc_item_fast().
*
*
* The @c zalloc_cached() track is used when zone caching is on:
* - @c zalloc_cached_fast() is taken when the cache has elements,
* - @c zalloc_cached_slow() is taken if a cache refill is needed.
* It can chose many strategies:
* ~ @c zalloc_cached_from_depot() to try to reuse cpu stashed magazines,
* ~ using the global recirculation depot @c z_recirc,
* ~ using zalloc_import() if the zone has enough elements,
* ~ falling back to the @c zalloc_item() track if zone caching is disabled
* due to VM pressure or the zone has no available elements.
*
* This track disables preemption for serialization:
* - preemption is disabled in @c zalloc_cached(),
* - kept disabled during @c zalloc_cached_slow(), converted into a zone lock
* if switching to @c zalloc_item_slow(),
* - preemption is reenabled in @c zalloc_cached_fast().
*
* @c zalloc_cached_from_depot() also takes depot locks (taken by the caller,
* released by @c zalloc_cached_from_depot().
*
* In general the @c zalloc_*_slow() codepaths deal with refilling and will
* tail call into the @c zalloc_*_fast() code to perform the actual allocation.
*
* @c zalloc_return() is the final function everyone tail calls into,
* which prepares the element for consumption by the caller and deals with
* common treatment (zone logging, tags, kasan, validation, ...).
*/
/*!
* @function zalloc_import
*
* @brief
* Import @c n elements in the specified array, opposite of @c zfree_drop().
*
* @param zone The zone to import elements from
* @param elems The array to import into
* @param n The number of elements to import. Must be non zero,
* and smaller than @c zone->z_elems_free.
*/
__header_always_inline void
zalloc_import(zone_t zone, zone_element_t *elems, uint32_t n)
{
vm_size_t esize = zone_elem_size(zone);
uint32_t i = 0;
assertf(STAILQ_EMPTY(&zone->z_recirc),
"Trying to import from zone %p [%s%s] with non empty recirc",
zone, zone_heap_name(zone), zone_name(zone));
do {
vm_offset_t page, eidx, size = 0;
struct zone_page_metadata *meta;
if (!zone_pva_is_null(zone->z_pageq_partial)) {
meta = zone_pva_to_meta(zone->z_pageq_partial);
page = zone_pva_to_addr(zone->z_pageq_partial);
} else if (!zone_pva_is_null(zone->z_pageq_empty)) {
meta = zone_pva_to_meta(zone->z_pageq_empty);
page = zone_pva_to_addr(zone->z_pageq_empty);
zone_counter_sub(zone, z_wired_empty, meta->zm_chunk_len);
} else {
zone_accounting_panic(zone, "z_elems_free corruption");
}
if (!zone_has_index(zone, meta->zm_index)) {
zone_page_metadata_index_confusion_panic(zone, page, meta);
}
vm_offset_t old_size = meta->zm_alloc_size;
vm_offset_t max_size = ptoa(meta->zm_chunk_len) + ZM_ALLOC_SIZE_LOCK;
do {
eidx = zone_meta_find_and_clear_bit(zone, meta);
elems[i++] = zone_element_encode(page, eidx, ZPM_AUTO);
size += esize;
} while (i < n && old_size + size + esize <= max_size);
vm_offset_t new_size = zone_meta_alloc_size_add(zone, meta, size);
if (new_size + esize > max_size) {
zone_meta_requeue(zone, &zone->z_pageq_full, meta);
} else if (old_size == 0) {
/* remove from free, move to intermediate */
zone_meta_requeue(zone, &zone->z_pageq_partial, meta);
}
} while (i < n);
}
/*!
* @function zalloc_return
*
* @brief
* Performs the tail-end of the work required on allocations before the caller
* uses them.
*
* @discussion
* This function is called without any zone lock held,
* and preemption back to the state it had when @c zalloc_ext() was called.
*
* @param zone The zone we're allocating from.
* @param ze The encoded element we just allocated.
* @param flags The flags passed to @c zalloc_ext() (for Z_ZERO).
* @param elem_size The element size for this zone.
* @param freemag An optional magazine that needs to be freed.
*/
__attribute__((noinline))
static void *
zalloc_return(zone_t zone, zone_element_t ze, zalloc_flags_t flags,
vm_offset_t elem_size, zone_magazine_t freemag)
{
vm_offset_t addr = zone_element_addr(ze, elem_size);
#if KASAN_ZALLOC
if (zone->z_percpu) {
zpercpu_foreach_cpu(i) {
kasan_poison_range(addr + ptoa(i), elem_size,
ASAN_VALID);
}
} else {
kasan_poison_range(addr, elem_size, ASAN_VALID);
}
#endif
#if ZALLOC_ENABLE_POISONING
zalloc_validate_element(zone, addr, elem_size, zone_element_prot(ze));
#endif /* ZALLOC_ENABLE_POISONING */
#if ZONE_ENABLE_LOGGING || CONFIG_ZLEAKS
if (__improbable(zalloc_should_log_or_trace_leaks(zone, elem_size))) {
zalloc_log_or_trace_leaks(zone, addr, __builtin_frame_address(0));
}
#endif /* ZONE_ENABLE_LOGGING || CONFIG_ZLEAKS */
#if KASAN_ZALLOC
if (zone->z_kasan_redzone) {
addr = kasan_alloc(addr, elem_size,
elem_size - 2 * zone->z_kasan_redzone,
zone->z_kasan_redzone);
elem_size -= 2 * zone->z_kasan_redzone;
}
/*
* Initialize buffer with unique pattern only if memory
* wasn't expected to be zeroed.
*/
if (!zone->z_free_zeroes && !(flags & Z_ZERO)) {
kasan_leak_init(addr, elem_size);
}
#endif /* KASAN_ZALLOC */
if ((flags & Z_ZERO) && !zone->z_free_zeroes) {
bzero((void *)addr, elem_size);
}
#if VM_MAX_TAG_ZONES
if (__improbable(zone->tags)) {
vm_tag_t tag = zalloc_flags_get_tag(flags);
if (tag == VM_KERN_MEMORY_NONE) {
tag = VM_KERN_MEMORY_KALLOC;
}
// set the tag with b0 clear so the block remains inuse
*ztSlot(zone, addr) = (vm_tag_t)(tag << 1);
vm_tag_update_zone_size(tag, zone->tag_zone_index,
(long)elem_size);
}
#endif /* VM_MAX_TAG_ZONES */
TRACE_MACHLEAKS(ZALLOC_CODE, ZALLOC_CODE_2, elem_size, addr);
DTRACE_VM2(zalloc, zone_t, zone, void*, addr);
if (freemag) {
zone_magazine_free(freemag);
}
return (void *)addr;
}
#if CONFIG_GZALLOC
/*!
* @function zalloc_gz
*
* @brief
* Performs allocations for zones using gzalloc.
*
* @discussion
* This function is noinline so that it doesn't affect the codegen
* of the fastpath.
*/
__attribute__((noinline))
static void *
zalloc_gz(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags)
{
vm_offset_t addr = gzalloc_alloc(zone, zstats, flags);
return zalloc_return(zone, zone_element_encode(addr, 0, ZPM_AUTO),
flags, zone_elem_size(zone), NULL);
}
#endif /* CONFIG_GZALLOC */
static void *
zalloc_item_fast(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags)
{
vm_size_t esize = zone_elem_size(zone);
zone_element_t ze;
zalloc_import(zone, &ze, 1);
zone_elems_free_sub(zone, 1);
zpercpu_get(zstats)->zs_mem_allocated += esize;
zone_unlock(zone);
return zalloc_return(zone, ze, flags, esize, NULL);
}
/*!
* @function zalloc_item_slow
*
* @brief
* Performs allocations when the zone is out of elements.
*
* @discussion
* This function might drop the lock and reenable preemption,
* which means the per-CPU caching layer or recirculation depot
* might have received elements.
*/
__attribute__((noinline))
static void *
zalloc_item_slow(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags)
{
if (zone->z_replenishes) {
zone_replenish_locked(zone);
} else {
if ((flags & Z_NOWAIT) == 0) {
zone_expand_locked(zone, flags, zalloc_needs_refill);
}
if (flags & (Z_NOWAIT | Z_NOPAGEWAIT)) {
zone_expand_async_schedule_if_needed(zone);
}
if (__improbable(zone->z_elems_free == 0)) {
zone_unlock(zone);
if (__improbable(flags & Z_NOFAIL)) {
zone_nofail_panic(zone);
}
DTRACE_VM2(zalloc, zone_t, zone, void*, NULL);
return NULL;
}
}
/*
* We might have changed core or got preempted/blocked while expanding
* the zone. Allocating from the zone when the recirculation depot
* is not empty is not allowed.
*
* It will be rare but possible for the depot to refill while we were
* waiting for pages. If that happens we need to start over.
*/
if (!STAILQ_EMPTY(&zone->z_recirc)) {
zone_unlock(zone);
return zalloc_ext(zone, zstats, flags);
}
return zalloc_item_fast(zone, zstats, flags);
}
/*!
* @function zalloc_item
*
* @brief
* Performs allocations when zone caching is off.
*
* @discussion
* This function calls @c zalloc_item_slow() when refilling the zone
* is needed, or @c zalloc_item_fast() if the zone has enough free elements.
*/
static void *
zalloc_item(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags)
{
zone_lock_check_contention(zone, NULL);
/*
* When we commited to the zalloc_item() path,
* zone caching might have been flipped/enabled.
*
* If we got preempted for long enough, the recirculation layer
* can have been populated, and allocating from the zone would be
* incorrect.
*
* So double check for this extremely rare race here.
*/
if (__improbable(!STAILQ_EMPTY(&zone->z_recirc))) {
zone_unlock(zone);
return zalloc_ext(zone, zstats, flags);
}
if (__improbable(zone->z_elems_free <= zone->z_elems_rsv)) {
return zalloc_item_slow(zone, zstats, flags);
}
return zalloc_item_fast(zone, zstats, flags);
}
static void *
zalloc_cached_fast(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags,
zone_cache_t cache, zone_magazine_t freemag)
{
vm_offset_t esize = zone_elem_size(zone);
zone_element_t ze;
uint32_t index;
index = --cache->zc_alloc_cur;
if (index >= zc_mag_size()) {
zone_accounting_panic(zone, "zc_alloc_cur wrap around");
}
ze = cache->zc_alloc_elems[index];
cache->zc_alloc_elems[index].ze_value = 0;
zpercpu_get(zstats)->zs_mem_allocated += esize;
enable_preemption();
if (zone_meta_is_free(zone_meta_from_element(ze), ze)) {
zone_meta_double_free_panic(zone, ze, __func__);
}
return zalloc_return(zone, ze, flags, esize, freemag);
}
static void *
zalloc_cached_from_depot(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags,
zone_cache_t cache, zone_cache_t depot, zone_magazine_t mag)
{
STAILQ_REMOVE_HEAD(&depot->zc_depot, zm_link);
if (depot->zc_depot_cur-- == 0) {
zone_accounting_panic(zone, "zc_depot_cur wrap-around");
}
zone_depot_unlock_nopreempt(depot);
mag = zone_magazine_replace(&cache->zc_alloc_cur,
&cache->zc_alloc_elems, mag);
z_debug_assert(cache->zc_alloc_cur == zc_mag_size());
z_debug_assert(mag->zm_cur == 0);
if (zone == zc_magazine_zone) {
enable_preemption();
bzero(mag, zone_elem_size(zone));
return mag;
}
return zalloc_cached_fast(zone, zstats, flags, cache, mag);
}
__attribute__((noinline))
static void *
zalloc_cached_slow(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags,
zone_cache_t cache)
{
zone_magazine_t mag = NULL;
struct zone_depot mags = STAILQ_HEAD_INITIALIZER(mags);
/*
* Try to allocate from our local depot, if there's one.
*/
if (STAILQ_FIRST(&cache->zc_depot)) {
zone_depot_lock_nopreempt(cache);
if ((mag = STAILQ_FIRST(&cache->zc_depot)) != NULL) {
return zalloc_cached_from_depot(zone, zstats, flags,
cache, cache, mag);
}
zone_depot_unlock_nopreempt(cache);
}
zone_lock_nopreempt_check_contention(zone, cache);
/*
* If the recirculation depot is empty, we'll need to import.
* The system is tuned for this to be extremely rare.
*/
if (__improbable(STAILQ_EMPTY(&zone->z_recirc))) {
uint16_t n_elems = zc_mag_size();
if (zone->z_elems_free < n_elems + zone->z_elems_rsv / 2 &&
os_sub_overflow(zone->z_elems_free,
zone->z_elems_rsv / 2, &n_elems)) {
n_elems = 0;
}
z_debug_assert(n_elems <= zc_mag_size());
if (__improbable(n_elems == 0)) {
/*
* If importing elements would deplete the zone,
* call zalloc_item_slow()
*/
return zalloc_item_slow(zone, zstats, flags);
}
if (__improbable(zone_caching_disabled)) {
if (__improbable(zone_caching_disabled < 0)) {
/*
* In the first 10s after boot, mess with
* the scan position in order to make early
* allocations patterns less predictible.
*/
zone_early_scramble_rr(zone, zstats);
}
return zalloc_item_fast(zone, zstats, flags);
}
zalloc_import(zone, cache->zc_alloc_elems, n_elems);
cache->zc_alloc_cur = n_elems;
zone_elems_free_sub(zone, n_elems);
zone_unlock_nopreempt(zone);
return zalloc_cached_fast(zone, zstats, flags, cache, NULL);
}
uint16_t n_mags = 0;
/*
* If the recirculation depot has elements, then try to fill
* the local per-cpu depot to (1 / zc_recirc_denom)
*/
do {
mag = STAILQ_FIRST(&zone->z_recirc);
STAILQ_REMOVE_HEAD(&zone->z_recirc, zm_link);
STAILQ_INSERT_TAIL(&mags, mag, zm_link);
n_mags++;
for (uint16_t i = 0; i < zc_mag_size(); i++) {
zone_element_t e = mag->zm_elems[i];
if (!zone_meta_mark_used(zone_meta_from_element(e), e)) {
zone_meta_double_free_panic(zone, e, __func__);
}
}
} while (!STAILQ_EMPTY(&zone->z_recirc) &&
zc_recirc_denom * n_mags * zc_mag_size() <= cache->zc_depot_max);
zone_elems_free_sub(zone, n_mags * zc_mag_size());
zone_counter_sub(zone, z_recirc_cur, n_mags);
zone_unlock_nopreempt(zone);
/*
* And then incorporate everything into our per-cpu layer.
*/
mag = STAILQ_FIRST(&mags);
STAILQ_REMOVE_HEAD(&mags, zm_link);
mag = zone_magazine_replace(&cache->zc_alloc_cur,
&cache->zc_alloc_elems, mag);
z_debug_assert(cache->zc_alloc_cur == zc_mag_size());
z_debug_assert(mag->zm_cur == 0);
if (--n_mags > 0) {
zone_depot_lock_nopreempt(cache);
cache->zc_depot_cur += n_mags;
STAILQ_CONCAT(&cache->zc_depot, &mags);
zone_depot_unlock_nopreempt(cache);
}
return zalloc_cached_fast(zone, zstats, flags, cache, mag);
}
/*!
* @function zalloc_cached
*
* @brief
* Performs allocations when zone caching is on.
*
* @discussion
* This function calls @c zalloc_cached_fast() when the caches have elements
* ready.
*
* Else it will call @c zalloc_cached_slow() so that the cache is refilled,
* which might switch to the @c zalloc_item_slow() track when the backing zone
* needs to be refilled.
*/
static void *
zalloc_cached(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags)
{
zone_cache_t cache;
disable_preemption();
cache = zpercpu_get(zone->z_pcpu_cache);
if (cache->zc_alloc_cur == 0) {
if (__improbable(cache->zc_free_cur == 0)) {
return zalloc_cached_slow(zone, zstats, flags, cache);
}
zone_cache_swap_magazines(cache);
}
return zalloc_cached_fast(zone, zstats, flags, cache, NULL);
}
/*!
* @function zalloc_ext
*
* @brief
* The core implementation of @c zalloc(), @c zalloc_flags(), @c zalloc_percpu().
*/
void *
zalloc_ext(zone_t zone, zone_stats_t zstats, zalloc_flags_t flags)
{
/*
* KASan uses zalloc() for fakestack, which can be called anywhere.
* However, we make sure these calls can never block.
*/
assert(zone->kasan_fakestacks ||
ml_get_interrupts_enabled() ||
ml_is_quiescing() ||
debug_mode_active() ||
startup_phase < STARTUP_SUB_EARLY_BOOT);
/*
* Make sure Z_NOFAIL was not obviously misused
*/
if (zone->z_replenishes) {
assert((flags & (Z_NOWAIT | Z_NOPAGEWAIT)) == 0);
} else if (flags & Z_NOFAIL) {
assert(!zone->exhaustible &&
(flags & (Z_NOWAIT | Z_NOPAGEWAIT)) == 0);
}
#if CONFIG_GZALLOC
if (__improbable(zone->gzalloc_tracked)) {
return zalloc_gz(zone, zstats, flags);
}
#endif /* CONFIG_GZALLOC */
if (zone->z_pcpu_cache) {
return zalloc_cached(zone, zstats, flags);
}
return zalloc_item(zone, zstats, flags);
}
void *
zalloc(union zone_or_view zov)
{
return zalloc_flags(zov, Z_WAITOK);
}
void *
zalloc_noblock(union zone_or_view zov)
{
return zalloc_flags(zov, Z_NOWAIT);
}
void *
zalloc_flags(union zone_or_view zov, zalloc_flags_t flags)
{
zone_t zone = zov.zov_view->zv_zone;
zone_stats_t zstats = zov.zov_view->zv_stats;
assert(!zone->z_percpu);
return zalloc_ext(zone, zstats, flags);
}
void *
zalloc_percpu(union zone_or_view zov, zalloc_flags_t flags)
{
zone_t zone = zov.zov_view->zv_zone;
zone_stats_t zstats = zov.zov_view->zv_stats;
assert(zone->z_percpu);
return (void *)__zpcpu_mangle(zalloc_ext(zone, zstats, flags));
}
static void *
_zalloc_permanent(zone_t zone, vm_size_t size, vm_offset_t mask)
{
struct zone_page_metadata *page_meta;
vm_offset_t offs, addr;
zone_pva_t pva;
assert(ml_get_interrupts_enabled() ||
ml_is_quiescing() ||
debug_mode_active() ||
startup_phase < STARTUP_SUB_EARLY_BOOT);
size = (size + mask) & ~mask;
assert(size <= PAGE_SIZE);
zone_lock(zone);
assert(zone->z_self == zone);
for (;;) {
pva = zone->z_pageq_partial;
while (!zone_pva_is_null(pva)) {
page_meta = zone_pva_to_meta(pva);
if (page_meta->zm_bump + size <= PAGE_SIZE) {
goto found;
}
pva = page_meta->zm_page_next;
}
zone_expand_locked(zone, Z_WAITOK, NULL);
}
found:
offs = (uint16_t)((page_meta->zm_bump + mask) & ~mask);
page_meta->zm_bump = (uint16_t)(offs + size);
page_meta->zm_alloc_size += size;
zone->z_elems_free -= size;
zpercpu_get(zone->z_stats)->zs_mem_allocated += size;
if (page_meta->zm_alloc_size >= PAGE_SIZE - sizeof(vm_offset_t)) {
zone_meta_requeue(zone, &zone->z_pageq_full, page_meta);
}
zone_unlock(zone);
addr = offs + zone_pva_to_addr(pva);
DTRACE_VM2(zalloc, zone_t, zone, void*, addr);
return (void *)addr;
}
static void *
_zalloc_permanent_large(size_t size, vm_offset_t mask)
{
kern_return_t kr;
vm_offset_t addr;
kr = kernel_memory_allocate(kernel_map, &addr, size, mask,
KMA_KOBJECT | KMA_PERMANENT | KMA_ZERO,
VM_KERN_MEMORY_KALLOC);
if (kr != 0) {
panic("zalloc_permanent: unable to allocate %zd bytes (%d)",
size, kr);
}
return (void *)addr;
}
void *
zalloc_permanent(vm_size_t size, vm_offset_t mask)
{
if (size <= PAGE_SIZE) {
zone_t zone = &zone_array[ZONE_ID_PERMANENT];
return _zalloc_permanent(zone, size, mask);
}
return _zalloc_permanent_large(size, mask);
}
void *
zalloc_percpu_permanent(vm_size_t size, vm_offset_t mask)
{
zone_t zone = &zone_array[ZONE_ID_PERCPU_PERMANENT];
return (void *)__zpcpu_mangle(_zalloc_permanent(zone, size, mask));
}
/*! @} */
#endif /* !ZALLOC_TEST */
#pragma mark zone GC / trimming
#if !ZALLOC_TEST
static thread_call_data_t zone_defrag_callout;
static void
zone_reclaim_chunk(zone_t z, struct zone_page_metadata *meta, uint32_t free_count)
{
vm_address_t page_addr;
vm_size_t size_to_free;
uint32_t bitmap_ref;
uint32_t page_count;
bool sequester = z->z_va_sequester && !z->z_destroyed;
zone_meta_queue_pop_native(z, &z->z_pageq_empty, &page_addr);
page_count = meta->zm_chunk_len;
if (meta->zm_alloc_size) {
zone_metadata_corruption(z, meta, "alloc_size");
}
if (z->z_percpu) {
if (page_count != 1) {
zone_metadata_corruption(z, meta, "page_count");
}
size_to_free = ptoa(z->z_chunk_pages);
os_atomic_sub(&zones_phys_page_mapped_count,
z->z_chunk_pages, relaxed);
} else {
if (page_count > z->z_chunk_pages) {
zone_metadata_corruption(z, meta, "page_count");
}
if (page_count < z->z_chunk_pages) {
/* Dequeue non populated VA from z_pageq_va */
zone_meta_remqueue(z, meta + page_count);
}
size_to_free = ptoa(page_count);
os_atomic_sub(&zones_phys_page_mapped_count, page_count, relaxed);
}
zone_counter_sub(z, z_elems_free, free_count);
zone_counter_sub(z, z_elems_avail, free_count);
zone_counter_sub(z, z_wired_empty, page_count);
zone_counter_sub(z, z_wired_cur, page_count);
if (z->z_elems_free_min < free_count) {
z->z_elems_free_min = 0;
} else {
z->z_elems_free_min -= free_count;
}
if (z->z_elems_free_max < free_count) {
z->z_elems_free_max = 0;
} else {
z->z_elems_free_max -= free_count;
}
bitmap_ref = 0;
if (sequester) {
if (meta->zm_inline_bitmap) {
for (int i = 0; i < meta->zm_chunk_len; i++) {
meta[i].zm_bitmap = 0;
}
} else {
bitmap_ref = meta->zm_bitmap;
meta->zm_bitmap = 0;
}
meta->zm_chunk_len = 0;
} else {
if (!meta->zm_inline_bitmap) {
bitmap_ref = meta->zm_bitmap;
}
zone_counter_sub(z, z_va_cur, z->z_percpu ? 1 : z->z_chunk_pages);
bzero(meta, sizeof(*meta) * z->z_chunk_pages);
}
zone_unlock(z);
if (bitmap_ref) {
zone_bits_free(bitmap_ref);
}
/* Free the pages for metadata and account for them */
#if KASAN_ZALLOC
kasan_poison_range(page_addr, size_to_free, ASAN_VALID);
#endif
#if VM_MAX_TAG_ZONES
if (z->tags) {
ztMemoryRemove(z, page_addr, size_to_free);
}
#endif /* VM_MAX_TAG_ZONES */
if (sequester) {
kernel_memory_depopulate(zone_submap(z), page_addr,
size_to_free, KMA_KOBJECT, VM_KERN_MEMORY_ZONE);
} else {
kmem_free(zone_submap(z), page_addr, ptoa(z->z_chunk_pages));
}
/*
* Freeing memory sometimes needs some (for example vm map entries
* to represent holes).
*
* If there are any active replenish threads, we need to let them work
* while we hold no locks. Only do so right after we just freed memory
* once however to give them even more chances to find fresh pages.
*/
zone_replenish_wait_if_needed();
thread_yield_to_preemption();
zone_lock(z);
if (sequester) {
zone_meta_queue_push(z, &z->z_pageq_va, meta);
}
}
static uint16_t
zone_reclaim_elements(zone_t z, uint16_t *count, zone_element_t *elems)
{
uint16_t n = *count;
z_debug_assert(n <= zc_mag_size());
for (uint16_t i = 0; i < n; i++) {
zone_element_t ze = elems[i];
elems[i].ze_value = 0;
zfree_drop(z, zone_element_validate(z, ze), ze, false);
}
*count = 0;
return n;
}
static uint16_t
zone_reclaim_recirc_magazine(zone_t z, struct zone_depot *mags)
{
zone_magazine_t mag = STAILQ_FIRST(&z->z_recirc);
STAILQ_REMOVE_HEAD(&z->z_recirc, zm_link);
STAILQ_INSERT_TAIL(mags, mag, zm_link);
zone_counter_sub(z, z_recirc_cur, 1);
z_debug_assert(mag->zm_cur == zc_mag_size());
for (uint16_t i = 0; i < zc_mag_size(); i++) {
zone_element_t ze = mag->zm_elems[i];
mag->zm_elems[i].ze_value = 0;
zfree_drop(z, zone_element_validate(z, ze), ze, true);
}
mag->zm_cur = 0;
return zc_mag_size();
}
static void
zone_depot_trim(zone_cache_t zc, struct zone_depot *head)
{
zone_magazine_t mag;
if (zc->zc_depot_cur == 0 ||
2 * (zc->zc_depot_cur + 1) * zc_mag_size() <= zc->zc_depot_max) {
return;
}
zone_depot_lock(zc);
while (zc->zc_depot_cur &&
2 * (zc->zc_depot_cur + 1) * zc_mag_size() > zc->zc_depot_max) {
mag = STAILQ_FIRST(&zc->zc_depot);
STAILQ_REMOVE_HEAD(&zc->zc_depot, zm_link);
STAILQ_INSERT_TAIL(head, mag, zm_link);
zc->zc_depot_cur--;
}
zone_depot_unlock(zc);
}
__enum_decl(zone_reclaim_mode_t, uint32_t, {
ZONE_RECLAIM_TRIM,
ZONE_RECLAIM_DRAIN,
ZONE_RECLAIM_DESTROY,
});
/*!
* @function zone_reclaim
*
* @brief
* Drains or trim the zone.
*
* @discussion
* Draining the zone will free it from all its elements.
*
* Trimming the zone tries to respect the working set size, and avoids draining
* the depot when it's not necessary.
*
* @param z The zone to reclaim from
* @param mode The purpose of this reclaim.
*/
static void
zone_reclaim(zone_t z, zone_reclaim_mode_t mode)
{
struct zone_depot mags = STAILQ_HEAD_INITIALIZER(mags);
zone_magazine_t mag, tmp;
zone_lock(z);
if (mode == ZONE_RECLAIM_DESTROY) {
if (!z->z_destructible || z->z_pcpu_cache ||
z->z_elems_rsv || z->z_allows_foreign) {
panic("zdestroy: Zone %s%s isn't destructible",
zone_heap_name(z), z->z_name);
}
if (!z->z_self || z->z_expander || z->z_expander_vm_priv ||
z->z_async_refilling || z->z_expanding_wait) {
panic("zdestroy: Zone %s%s in an invalid state for destruction",
zone_heap_name(z), z->z_name);
}
#if !KASAN_ZALLOC
/*
* Unset the valid bit. We'll hit an assert failure on further
* operations on this zone, until zinit() is called again.
*
* Leave the zone valid for KASan as we will see zfree's on
* quarantined free elements even after the zone is destroyed.
*/
z->z_self = NULL;
#endif
z->z_destroyed = true;
} else if (z->z_destroyed) {
return zone_unlock(z);
} else if (z->z_replenishes && z->z_async_refilling) {
/*
* If the zone is replenishing, leave it alone.
*/
return zone_unlock(z);
}
if (z->z_pcpu_cache) {
if (mode != ZONE_RECLAIM_TRIM) {
zpercpu_foreach(zc, z->z_pcpu_cache) {
zc->zc_depot_max /= 2;
}
} else {
zpercpu_foreach(zc, z->z_pcpu_cache) {
if (zc->zc_depot_max > 0) {
zc->zc_depot_max--;
}
}
}
zone_unlock(z);
if (mode == ZONE_RECLAIM_TRIM) {
zpercpu_foreach(zc, z->z_pcpu_cache) {
zone_depot_trim(zc, &mags);
}
} else {
zpercpu_foreach(zc, z->z_pcpu_cache) {
zone_depot_lock(zc);
STAILQ_CONCAT(&mags, &zc->zc_depot);
zc->zc_depot_cur = 0;
zone_depot_unlock(zc);
}
}
zone_lock(z);
uint32_t freed = 0;
STAILQ_FOREACH(mag, &mags, zm_link) {
freed += zone_reclaim_elements(z,
&mag->zm_cur, mag->zm_elems);
if (freed >= zc_free_batch_size) {
z->z_elems_free_min += freed;
z->z_elems_free_max += freed;
z->z_elems_free += freed;
zone_unlock(z);
thread_yield_to_preemption();
zone_lock(z);
freed = 0;
}
}
if (mode == ZONE_RECLAIM_DESTROY) {
zpercpu_foreach(zc, z->z_pcpu_cache) {
freed += zone_reclaim_elements(z,
&zc->zc_alloc_cur, zc->zc_alloc_elems);
freed += zone_reclaim_elements(z,
&zc->zc_free_cur, zc->zc_free_elems);
}
z->z_elems_free_wss = 0;
z->z_elems_free_min = 0;
z->z_elems_free_max = 0;
z->z_contention_cur = 0;
z->z_contention_wma = 0;
} else {
z->z_elems_free_min += freed;
z->z_elems_free_max += freed;
}
z->z_elems_free += freed;
}
for (;;) {
struct zone_page_metadata *meta;
uint32_t count, goal, freed = 0;
goal = z->z_elems_rsv;
if (mode == ZONE_RECLAIM_TRIM) {
/*
* When trimming, only free elements in excess
* of the working set estimate.
*
* However if we are in a situation where the working
* set estimate is clearly growing, ignore the estimate
* as the next working set update will grow it and
* we want to avoid churn.
*/
goal = MAX(goal, MAX(z->z_elems_free_wss,
z->z_elems_free - z->z_elems_free_min));
/*
* Add some slop to account for "the last partial chunk in flight"
* so that we do not deplete the recirculation depot too harshly.
*/
goal += z->z_chunk_elems / 2;
}
if (z->z_elems_free <= goal) {
break;
}
/*
* If we're above target, but we have no free page, then drain
* the recirculation depot until we get a free chunk or exhaust
* the depot.
*
* This is rather abrupt but also somehow will reduce
* fragmentation anyway, and the zone code will import
* over time anyway.
*/
while (z->z_recirc_cur) {
if (z->z_recirc_cur * zc_mag_size() <= goal &&
!zone_pva_is_null(z->z_pageq_empty)) {
break;
}
if (freed >= zc_free_batch_size) {
zone_unlock(z);
thread_yield_to_preemption();
zone_lock(z);
freed = 0;
/* we dropped the lock, needs to reassess */
continue;
}
freed += zone_reclaim_recirc_magazine(z, &mags);
}
if (zone_pva_is_null(z->z_pageq_empty)) {
break;
}
meta = zone_pva_to_meta(z->z_pageq_empty);
count = (uint32_t)ptoa(meta->zm_chunk_len) / zone_elem_size(z);
if (z->z_elems_free - count < goal) {
break;
}
zone_reclaim_chunk(z, meta, count);
}
zone_unlock(z);
STAILQ_FOREACH_SAFE(mag, &mags, zm_link, tmp) {
zone_magazine_free(mag);
}
}
static void
zone_reclam_all(zone_reclaim_mode_t mode)
{
/*
* Start with zones with VA sequester since depopulating
* pages will not need to allocate vm map entries for holes,
* which will give memory back to the system faster.
*/
zone_foreach(z) {
if (z == zc_magazine_zone) {
continue;
}
if (z->z_va_sequester && z->collectable) {
zone_reclaim(z, mode);
}
}
zone_foreach(z) {
if (z == zc_magazine_zone) {
continue;
}
if (!z->z_va_sequester && z->collectable) {
zone_reclaim(z, mode);
}
}
zone_reclaim(zc_magazine_zone, mode);
}
void
zone_gc(zone_gc_level_t level)
{
zone_reclaim_mode_t mode;
switch (level) {
case ZONE_GC_TRIM:
mode = ZONE_RECLAIM_TRIM;
break;
case ZONE_GC_DRAIN:
mode = ZONE_RECLAIM_DRAIN;
break;
case ZONE_GC_JETSAM:
kill_process_in_largest_zone();
mode = ZONE_RECLAIM_TRIM;
break;
}
current_thread()->options |= TH_OPT_ZONE_PRIV;
lck_mtx_lock(&zone_gc_lock);
zone_reclam_all(mode);
if (level == ZONE_GC_JETSAM && zone_map_nearing_exhaustion()) {
/*
* If we possibly killed a process, but we're still critical,
* we need to drain harder.
*/
zone_reclam_all(ZONE_RECLAIM_DRAIN);
}
lck_mtx_unlock(&zone_gc_lock);
current_thread()->options &= ~TH_OPT_ZONE_PRIV;
}
void
zone_gc_trim(void)
{
zone_gc(ZONE_GC_TRIM);
}
void
zone_gc_drain(void)
{
zone_gc(ZONE_GC_DRAIN);
}
static bool
zone_defrag_needed(zone_t z)
{
uint32_t recirc_size = z->z_recirc_cur * zc_mag_size();
if (recirc_size <= z->z_chunk_elems / 2) {
return false;
}
return recirc_size * zc_defrag_ratio > z->z_elems_free_wss * 100;
}
/*!
* @function zone_defrag_async
*
* @brief
* Resize the recirculation depot to match the working set size.
*
* @discussion
* When zones grow very large due to a spike in usage, and then some of those
* elements get freed, the elements in magazines in the recirculation depot
* are in no particular order.
*
* In order to control fragmentation, we need to detect "empty" pages so that
* they get onto the @c z_pageq_empty freelist, so that allocations re-pack
* naturally.
*
* This is done very gently, never in excess of the working set and some slop.
*/
static void
zone_defrag_async(__unused thread_call_param_t p0, __unused thread_call_param_t p1)
{
zone_foreach(z) {
struct zone_depot mags = STAILQ_HEAD_INITIALIZER(mags);
zone_magazine_t mag, tmp;
uint32_t freed = 0, goal = 0;
if (!z->collectable || !zone_defrag_needed(z)) {
continue;
}
zone_lock(z);
goal = z->z_elems_free_wss + z->z_chunk_elems / 2 +
zc_mag_size() - 1;
while (z->z_recirc_cur * zc_mag_size() > goal) {
if (freed >= zc_free_batch_size) {
zone_unlock(z);
thread_yield_to_preemption();
zone_lock(z);
freed = 0;
/* we dropped the lock, needs to reassess */
continue;
}
freed += zone_reclaim_recirc_magazine(z, &mags);
}
zone_unlock(z);
STAILQ_FOREACH_SAFE(mag, &mags, zm_link, tmp) {
zone_magazine_free(mag);
}
}
}
void
compute_zone_working_set_size(__unused void *param)
{
uint32_t zc_auto = zc_auto_threshold;
bool kick_defrag = false;
/*
* Keep zone caching disabled until the first proc is made.
*/
if (__improbable(zone_caching_disabled < 0)) {
return;
}
zone_caching_disabled = vm_pool_low();
#if ZALLOC_EARLY_GAPS
zone_cleanup_early_gaps_if_needed();
#endif
if (os_mul_overflow(zc_auto, Z_CONTENTION_WMA_UNIT, &zc_auto)) {
zc_auto = 0;
}
zone_foreach(z) {
uint32_t wma;
bool needs_caching = false;
if (z->z_self != z) {
continue;
}
zone_lock(z);
wma = z->z_elems_free_max - z->z_elems_free_min;
wma = (3 * wma + z->z_elems_free_wss) / 4;
z->z_elems_free_max = z->z_elems_free_min = z->z_elems_free;
z->z_elems_free_wss = wma;
if (!kick_defrag && zone_defrag_needed(z)) {
kick_defrag = true;
}
/* fixed point decimal of contentions per second */
wma = z->z_contention_cur * Z_CONTENTION_WMA_UNIT /
ZONE_WSS_UPDATE_PERIOD;
z->z_contention_cur = 0;
z->z_contention_wma = (3 * wma + z->z_contention_wma) / 4;
/*
* If the zone seems to be very quiet,
* gently lower its cpu-local depot size.
*/
if (z->z_pcpu_cache && wma < Z_CONTENTION_WMA_UNIT / 2 &&
z->z_contention_wma < Z_CONTENTION_WMA_UNIT / 2) {
zpercpu_foreach(zc, z->z_pcpu_cache) {
if (zc->zc_depot_max > zc_mag_size()) {
zc->zc_depot_max--;
}
}
}
/*
* If the zone has been contending like crazy for two periods,
* and is eligible, maybe it's time to enable caching.
*/
if (!z->z_nocaching && !z->z_pcpu_cache && !z->exhaustible &&
zc_auto && z->z_contention_wma >= zc_auto && wma >= zc_auto) {
needs_caching = true;
}
zone_unlock(z);
if (needs_caching) {
zone_enable_caching(z);
}
}
if (kick_defrag) {
thread_call_enter(&zone_defrag_callout);
}
}
#endif /* !ZALLOC_TEST */
#pragma mark vm integration, MIG routines
#if !ZALLOC_TEST
/*
* Creates a vm_map_copy_t to return to the caller of mach_* MIG calls
* requesting zone information.
* Frees unused pages towards the end of the region, and zero'es out unused
* space on the last page.
*/
static vm_map_copy_t
create_vm_map_copy(
vm_offset_t start_addr,
vm_size_t total_size,
vm_size_t used_size)
{
kern_return_t kr;
vm_offset_t end_addr;
vm_size_t free_size;
vm_map_copy_t copy;
if (used_size != total_size) {
end_addr = start_addr + used_size;
free_size = total_size - (round_page(end_addr) - start_addr);
if (free_size >= PAGE_SIZE) {
kmem_free(ipc_kernel_map,
round_page(end_addr), free_size);
}
bzero((char *) end_addr, round_page(end_addr) - end_addr);
}
kr = vm_map_copyin(ipc_kernel_map, (vm_map_address_t)start_addr,
(vm_map_size_t)used_size, TRUE, &copy);
assert(kr == KERN_SUCCESS);
return copy;
}
static boolean_t
get_zone_info(
zone_t z,
mach_zone_name_t *zn,
mach_zone_info_t *zi)
{
struct zone zcopy;
vm_size_t cached = 0;
assert(z != ZONE_NULL);
zone_lock(z);
if (!z->z_self) {
zone_unlock(z);
return FALSE;
}
zcopy = *z;
if (z->z_pcpu_cache) {
zpercpu_foreach(zc, z->z_pcpu_cache) {
cached += zc->zc_alloc_cur + zc->zc_free_cur;
cached += zc->zc_depot_cur * zc_mag_size();
}
}
zone_unlock(z);
if (zn != NULL) {
/*
* Append kalloc heap name to zone name (if zone is used by kalloc)
*/
char temp_zone_name[MAX_ZONE_NAME] = "";
snprintf(temp_zone_name, MAX_ZONE_NAME, "%s%s",
zone_heap_name(z), z->z_name);
/* assuming here the name data is static */
(void) __nosan_strlcpy(zn->mzn_name, temp_zone_name,
strlen(temp_zone_name) + 1);
}
if (zi != NULL) {
*zi = (mach_zone_info_t) {
.mzi_count = zone_count_allocated(&zcopy) - cached,
.mzi_cur_size = ptoa_64(zone_scale_for_percpu(&zcopy, zcopy.z_wired_cur)),
// max_size for zprint is now high-watermark of pages used
.mzi_max_size = ptoa_64(zone_scale_for_percpu(&zcopy, zcopy.z_wired_hwm)),
.mzi_elem_size = zone_scale_for_percpu(&zcopy, zcopy.z_elem_size),
.mzi_alloc_size = ptoa_64(zcopy.z_chunk_pages),
.mzi_exhaustible = (uint64_t)zcopy.exhaustible,
};
zpercpu_foreach(zs, zcopy.z_stats) {
zi->mzi_sum_size += zs->zs_mem_allocated;
}
if (zcopy.collectable) {
SET_MZI_COLLECTABLE_BYTES(zi->mzi_collectable,
ptoa_64(zone_scale_for_percpu(&zcopy, zcopy.z_wired_empty)));
SET_MZI_COLLECTABLE_FLAG(zi->mzi_collectable, TRUE);
}
}
return TRUE;
}
kern_return_t
task_zone_info(
__unused task_t task,
__unused mach_zone_name_array_t *namesp,
__unused mach_msg_type_number_t *namesCntp,
__unused task_zone_info_array_t *infop,
__unused mach_msg_type_number_t *infoCntp)
{
return KERN_FAILURE;
}
kern_return_t
mach_zone_info(
host_priv_t host,
mach_zone_name_array_t *namesp,
mach_msg_type_number_t *namesCntp,
mach_zone_info_array_t *infop,
mach_msg_type_number_t *infoCntp)
{
return mach_memory_info(host, namesp, namesCntp, infop, infoCntp, NULL, NULL);
}
kern_return_t
mach_memory_info(
host_priv_t host,
mach_zone_name_array_t *namesp,
mach_msg_type_number_t *namesCntp,
mach_zone_info_array_t *infop,
mach_msg_type_number_t *infoCntp,
mach_memory_info_array_t *memoryInfop,
mach_msg_type_number_t *memoryInfoCntp)
{
mach_zone_name_t *names;
vm_offset_t names_addr;
vm_size_t names_size;
mach_zone_info_t *info;
vm_offset_t info_addr;
vm_size_t info_size;
mach_memory_info_t *memory_info;
vm_offset_t memory_info_addr;
vm_size_t memory_info_size;
vm_size_t memory_info_vmsize;
unsigned int num_info;
unsigned int max_zones, used_zones, i;
mach_zone_name_t *zn;
mach_zone_info_t *zi;
kern_return_t kr;
uint64_t zones_collectable_bytes = 0;
if (host == HOST_NULL) {
return KERN_INVALID_HOST;
}
#if CONFIG_DEBUGGER_FOR_ZONE_INFO
if (!PE_i_can_has_debugger(NULL)) {
return KERN_INVALID_HOST;
}
#endif
/*
* We assume that zones aren't freed once allocated.
* We won't pick up any zones that are allocated later.
*/
max_zones = os_atomic_load(&num_zones, relaxed);
names_size = round_page(max_zones * sizeof *names);
kr = kmem_alloc_pageable(ipc_kernel_map,
&names_addr, names_size, VM_KERN_MEMORY_IPC);
if (kr != KERN_SUCCESS) {
return kr;
}
names = (mach_zone_name_t *) names_addr;
info_size = round_page(max_zones * sizeof *info);
kr = kmem_alloc_pageable(ipc_kernel_map,
&info_addr, info_size, VM_KERN_MEMORY_IPC);
if (kr != KERN_SUCCESS) {
kmem_free(ipc_kernel_map,
names_addr, names_size);
return kr;
}
info = (mach_zone_info_t *) info_addr;
zn = &names[0];
zi = &info[0];
used_zones = max_zones;
for (i = 0; i < max_zones; i++) {
if (!get_zone_info(&(zone_array[i]), zn, zi)) {
used_zones--;
continue;
}
zones_collectable_bytes += GET_MZI_COLLECTABLE_BYTES(zi->mzi_collectable);
zn++;
zi++;
}
*namesp = (mach_zone_name_t *) create_vm_map_copy(names_addr, names_size, used_zones * sizeof *names);
*namesCntp = used_zones;
*infop = (mach_zone_info_t *) create_vm_map_copy(info_addr, info_size, used_zones * sizeof *info);
*infoCntp = used_zones;
num_info = 0;
memory_info_addr = 0;
if (memoryInfop && memoryInfoCntp) {
vm_map_copy_t copy;
num_info = vm_page_diagnose_estimate();
memory_info_size = num_info * sizeof(*memory_info);
memory_info_vmsize = round_page(memory_info_size);
kr = kmem_alloc_pageable(ipc_kernel_map,
&memory_info_addr, memory_info_vmsize, VM_KERN_MEMORY_IPC);
if (kr != KERN_SUCCESS) {
return kr;
}
kr = vm_map_wire_kernel(ipc_kernel_map, memory_info_addr, memory_info_addr + memory_info_vmsize,
VM_PROT_READ | VM_PROT_WRITE, VM_KERN_MEMORY_IPC, FALSE);
assert(kr == KERN_SUCCESS);
memory_info = (mach_memory_info_t *) memory_info_addr;
vm_page_diagnose(memory_info, num_info, zones_collectable_bytes);
kr = vm_map_unwire(ipc_kernel_map, memory_info_addr, memory_info_addr + memory_info_vmsize, FALSE);
assert(kr == KERN_SUCCESS);
kr = vm_map_copyin(ipc_kernel_map, (vm_map_address_t)memory_info_addr,
(vm_map_size_t)memory_info_size, TRUE, &copy);
assert(kr == KERN_SUCCESS);
*memoryInfop = (mach_memory_info_t *) copy;
*memoryInfoCntp = num_info;
}
return KERN_SUCCESS;
}
kern_return_t
mach_zone_info_for_zone(
host_priv_t host,
mach_zone_name_t name,
mach_zone_info_t *infop)
{
zone_t zone_ptr;
if (host == HOST_NULL) {
return KERN_INVALID_HOST;
}
#if CONFIG_DEBUGGER_FOR_ZONE_INFO
if (!PE_i_can_has_debugger(NULL)) {
return KERN_INVALID_HOST;
}
#endif
if (infop == NULL) {
return KERN_INVALID_ARGUMENT;
}
zone_ptr = ZONE_NULL;
zone_foreach(z) {
/*
* Append kalloc heap name to zone name (if zone is used by kalloc)
*/
char temp_zone_name[MAX_ZONE_NAME] = "";
snprintf(temp_zone_name, MAX_ZONE_NAME, "%s%s",
zone_heap_name(z), z->z_name);
/* Find the requested zone by name */
if (track_this_zone(temp_zone_name, name.mzn_name)) {
zone_ptr = z;
break;
}
}
/* No zones found with the requested zone name */
if (zone_ptr == ZONE_NULL) {
return KERN_INVALID_ARGUMENT;
}
if (get_zone_info(zone_ptr, NULL, infop)) {
return KERN_SUCCESS;
}
return KERN_FAILURE;
}
kern_return_t
mach_zone_info_for_largest_zone(
host_priv_t host,
mach_zone_name_t *namep,
mach_zone_info_t *infop)
{
if (host == HOST_NULL) {
return KERN_INVALID_HOST;
}
#if CONFIG_DEBUGGER_FOR_ZONE_INFO
if (!PE_i_can_has_debugger(NULL)) {
return KERN_INVALID_HOST;
}
#endif
if (namep == NULL || infop == NULL) {
return KERN_INVALID_ARGUMENT;
}
if (get_zone_info(zone_find_largest(), namep, infop)) {
return KERN_SUCCESS;
}
return KERN_FAILURE;
}
uint64_t
get_zones_collectable_bytes(void)
{
uint64_t zones_collectable_bytes = 0;
mach_zone_info_t zi;
zone_foreach(z) {
if (get_zone_info(z, NULL, &zi)) {
zones_collectable_bytes +=
GET_MZI_COLLECTABLE_BYTES(zi.mzi_collectable);
}
}
return zones_collectable_bytes;
}
kern_return_t
mach_zone_get_zlog_zones(
host_priv_t host,
mach_zone_name_array_t *namesp,
mach_msg_type_number_t *namesCntp)
{
#if ZONE_ENABLE_LOGGING
unsigned int max_zones, logged_zones, i;
kern_return_t kr;
zone_t zone_ptr;
mach_zone_name_t *names;
vm_offset_t names_addr;
vm_size_t names_size;
if (host == HOST_NULL) {
return KERN_INVALID_HOST;
}
if (namesp == NULL || namesCntp == NULL) {
return KERN_INVALID_ARGUMENT;
}
max_zones = os_atomic_load(&num_zones, relaxed);
names_size = round_page(max_zones * sizeof *names);
kr = kmem_alloc_pageable(ipc_kernel_map,
&names_addr, names_size, VM_KERN_MEMORY_IPC);
if (kr != KERN_SUCCESS) {
return kr;
}
names = (mach_zone_name_t *) names_addr;
zone_ptr = ZONE_NULL;
logged_zones = 0;
for (i = 0; i < max_zones; i++) {
zone_t z = &(zone_array[i]);
assert(z != ZONE_NULL);
/* Copy out the zone name if zone logging is enabled */
if (z->zlog_btlog) {
get_zone_info(z, &names[logged_zones], NULL);
logged_zones++;
}
}
*namesp = (mach_zone_name_t *) create_vm_map_copy(names_addr, names_size, logged_zones * sizeof *names);
*namesCntp = logged_zones;
return KERN_SUCCESS;
#else /* ZONE_ENABLE_LOGGING */
#pragma unused(host, namesp, namesCntp)
return KERN_FAILURE;
#endif /* ZONE_ENABLE_LOGGING */
}
kern_return_t
mach_zone_get_btlog_records(
host_priv_t host,
mach_zone_name_t name,
zone_btrecord_array_t *recsp,
mach_msg_type_number_t *recsCntp)
{
#if DEBUG || DEVELOPMENT
unsigned int numrecs = 0;
zone_btrecord_t *recs;
kern_return_t kr;
zone_t zone_ptr;
vm_offset_t recs_addr;
vm_size_t recs_size;
if (host == HOST_NULL) {
return KERN_INVALID_HOST;
}
if (recsp == NULL || recsCntp == NULL) {
return KERN_INVALID_ARGUMENT;
}
zone_ptr = ZONE_NULL;
zone_foreach(z) {
/*
* Append kalloc heap name to zone name (if zone is used by kalloc)
*/
char temp_zone_name[MAX_ZONE_NAME] = "";
snprintf(temp_zone_name, MAX_ZONE_NAME, "%s%s",
zone_heap_name(z), z->z_name);
/* Find the requested zone by name */
if (track_this_zone(temp_zone_name, name.mzn_name)) {
zone_ptr = z;
break;
}
}
/* No zones found with the requested zone name */
if (zone_ptr == ZONE_NULL) {
return KERN_INVALID_ARGUMENT;
}
/* Logging not turned on for the requested zone */
if (!DO_LOGGING(zone_ptr)) {
return KERN_FAILURE;
}
/* Allocate memory for btlog records */
numrecs = (unsigned int)(get_btlog_records_count(zone_ptr->zlog_btlog));
recs_size = round_page(numrecs * sizeof *recs);
kr = kmem_alloc_pageable(ipc_kernel_map, &recs_addr, recs_size, VM_KERN_MEMORY_IPC);
if (kr != KERN_SUCCESS) {
return kr;
}
/*
* We will call get_btlog_records() below which populates this region while holding a spinlock
* (the btlog lock). So these pages need to be wired.
*/
kr = vm_map_wire_kernel(ipc_kernel_map, recs_addr, recs_addr + recs_size,
VM_PROT_READ | VM_PROT_WRITE, VM_KERN_MEMORY_IPC, FALSE);
assert(kr == KERN_SUCCESS);
recs = (zone_btrecord_t *)recs_addr;
get_btlog_records(zone_ptr->zlog_btlog, recs, &numrecs);
kr = vm_map_unwire(ipc_kernel_map, recs_addr, recs_addr + recs_size, FALSE);
assert(kr == KERN_SUCCESS);
*recsp = (zone_btrecord_t *) create_vm_map_copy(recs_addr, recs_size, numrecs * sizeof *recs);
*recsCntp = numrecs;
return KERN_SUCCESS;
#else /* DEBUG || DEVELOPMENT */
#pragma unused(host, name, recsp, recsCntp)
return KERN_FAILURE;
#endif /* DEBUG || DEVELOPMENT */
}
#if DEBUG || DEVELOPMENT
kern_return_t
mach_memory_info_check(void)
{
mach_memory_info_t * memory_info;
mach_memory_info_t * info;
unsigned int num_info;
vm_offset_t memory_info_addr;
kern_return_t kr;
size_t memory_info_size, memory_info_vmsize;
uint64_t top_wired, zonestotal, total;
num_info = vm_page_diagnose_estimate();
memory_info_size = num_info * sizeof(*memory_info);
memory_info_vmsize = round_page(memory_info_size);
kr = kmem_alloc(kernel_map, &memory_info_addr, memory_info_vmsize, VM_KERN_MEMORY_DIAG);
assert(kr == KERN_SUCCESS);
memory_info = (mach_memory_info_t *) memory_info_addr;
vm_page_diagnose(memory_info, num_info, 0);
top_wired = total = zonestotal = 0;
zone_foreach(z) {
zonestotal += zone_size_wired(z);
}
for (uint32_t idx = 0; idx < num_info; idx++) {
info = &memory_info[idx];
if (!info->size) {
continue;
}
if (VM_KERN_COUNT_WIRED == info->site) {
top_wired = info->size;
}
if (VM_KERN_SITE_HIDE & info->flags) {
continue;
}
if (!(VM_KERN_SITE_WIRED & info->flags)) {
continue;
}
total += info->size;
}
total += zonestotal;
printf("vm_page_diagnose_check %qd of %qd, zones %qd, short 0x%qx\n",
total, top_wired, zonestotal, top_wired - total);
kmem_free(kernel_map, memory_info_addr, memory_info_vmsize);
return kr;
}
extern boolean_t(*volatile consider_buffer_cache_collect)(int);
#endif /* DEBUG || DEVELOPMENT */
kern_return_t
mach_zone_force_gc(
host_t host)
{
if (host == HOST_NULL) {
return KERN_INVALID_HOST;
}
#if DEBUG || DEVELOPMENT
/* Callout to buffer cache GC to drop elements in the apfs zones */
if (consider_buffer_cache_collect != NULL) {
(void)(*consider_buffer_cache_collect)(0);
}
zone_gc(ZONE_GC_DRAIN);
#endif /* DEBUG || DEVELOPMENT */
return KERN_SUCCESS;
}
zone_t
zone_find_largest(void)
{
uint32_t largest_idx = 0;
vm_offset_t largest_size = zone_size_wired(&zone_array[0]);
zone_index_foreach(i) {
vm_offset_t size = zone_size_wired(&zone_array[i]);
if (size > largest_size) {
largest_idx = i;
largest_size = size;
}
}
return &zone_array[largest_idx];
}
#endif /* !ZALLOC_TEST */
#pragma mark zone creation, configuration, destruction
#if !ZALLOC_TEST
static zone_t
zone_init_defaults(zone_id_t zid)
{
zone_t z = &zone_array[zid];
z->z_wired_max = ~0u;
z->collectable = true;
z->expandable = true;
z->z_submap_idx = Z_SUBMAP_IDX_GENERAL;
lck_spin_init(&z->z_lock, &zone_locks_grp, LCK_ATTR_NULL);
STAILQ_INIT(&z->z_recirc);
return z;
}
static bool
zone_is_initializing(zone_t z)
{
return !z->z_self && !z->z_destroyed;
}
void
zone_set_submap_idx(zone_t zone, unsigned int sub_map_idx)
{
if (!zone_is_initializing(zone)) {
panic("%s: called after zone_create()", __func__);
}
if (sub_map_idx > zone_last_submap_idx) {
panic("zone_set_submap_idx(%d) > %d", sub_map_idx, zone_last_submap_idx);
}
zone->z_submap_idx = sub_map_idx;
}
void
zone_set_noexpand(zone_t zone, vm_size_t nelems)
{
if (!zone_is_initializing(zone)) {
panic("%s: called after zone_create()", __func__);
}
zone->expandable = false;
zone->z_wired_max = zone_alloc_pages_for_nelems(zone, nelems);
}
void
zone_set_exhaustible(zone_t zone, vm_size_t nelems)
{
if (!zone_is_initializing(zone)) {
panic("%s: called after zone_create()", __func__);
}
zone->expandable = false;
zone->exhaustible = true;
zone->z_wired_max = zone_alloc_pages_for_nelems(zone, nelems);
}
/**
* @function zone_create_find
*
* @abstract
* Finds an unused zone for the given name and element size.
*
* @param name the zone name
* @param size the element size (including redzones, ...)
* @param flags the flags passed to @c zone_create*
* @param zid_inout the desired zone ID or ZONE_ID_ANY
*
* @returns a zone to initialize further.
*/
static zone_t
zone_create_find(
const char *name,
vm_size_t size,
zone_create_flags_t flags,
zone_id_t *zid_inout)
{
zone_id_t nzones, zid = *zid_inout;
zone_t z;
simple_lock(&all_zones_lock, &zone_locks_grp);
nzones = (zone_id_t)os_atomic_load(&num_zones, relaxed);
assert(num_zones_in_use <= nzones && nzones < MAX_ZONES);
if (__improbable(nzones < ZONE_ID__FIRST_DYNAMIC)) {
/*
* The first time around, make sure the reserved zone IDs
* have an initialized lock as zone_index_foreach() will
* enumerate them.
*/
while (nzones < ZONE_ID__FIRST_DYNAMIC) {
zone_init_defaults(nzones++);
}
os_atomic_store(&num_zones, nzones, release);
}
if (zid != ZONE_ID_ANY) {
if (zid >= ZONE_ID__FIRST_DYNAMIC) {
panic("zone_create: invalid desired zone ID %d for %s",
zid, name);
}
if (flags & ZC_DESTRUCTIBLE) {
panic("zone_create: ID %d (%s) must be permanent", zid, name);
}
if (zone_array[zid].z_self) {
panic("zone_create: creating zone ID %d (%s) twice", zid, name);
}
z = &zone_array[zid];
} else {
if (flags & ZC_DESTRUCTIBLE) {
/*
* If possible, find a previously zdestroy'ed zone in the
* zone_array that we can reuse.
*/
for (int i = bitmap_first(zone_destroyed_bitmap, MAX_ZONES);
i >= 0; i = bitmap_next(zone_destroyed_bitmap, i)) {
z = &zone_array[i];
/*
* If the zone name and the element size are the
* same, we can just reuse the old zone struct.
*/
if (strcmp(z->z_name, name) || zone_elem_size(z) != size) {
continue;
}
bitmap_clear(zone_destroyed_bitmap, i);
z->z_destroyed = false;
z->z_self = z;
zid = (zone_id_t)i;
goto out;
}
}
zid = nzones++;
z = zone_init_defaults(zid);
/*
* The release barrier pairs with the acquire in
* zone_index_foreach() and makes sure that enumeration loops
* always see an initialized zone lock.
*/
os_atomic_store(&num_zones, nzones, release);
}
out:
num_zones_in_use++;
simple_unlock(&all_zones_lock);
*zid_inout = zid;
return z;
}
__abortlike
static void
zone_create_panic(const char *name, const char *f1, const char *f2)
{
panic("zone_create: creating zone %s: flag %s and %s are incompatible",
name, f1, f2);
}
#define zone_create_assert_not_both(name, flags, current_flag, forbidden_flag) \
if ((flags) & forbidden_flag) { \
zone_create_panic(name, #current_flag, #forbidden_flag); \
}
/*
* Adjusts the size of the element based on minimum size, alignment
* and kasan redzones
*/
static vm_size_t
zone_elem_adjust_size(
const char *name __unused,
vm_size_t elem_size,
zone_create_flags_t flags __unused,
uint32_t *redzone __unused)
{
vm_size_t size;
/*
* Adjust element size for minimum size and pointer alignment
*/
size = (elem_size + sizeof(vm_offset_t) - 1) & -sizeof(vm_offset_t);
if (size < ZONE_MIN_ELEM_SIZE) {
size = ZONE_MIN_ELEM_SIZE;
}
#if KASAN_ZALLOC
/*
* Expand the zone allocation size to include the redzones.
*
* For page-multiple zones add a full guard page because they
* likely require alignment.
*/
uint32_t redzone_tmp;
if (flags & (ZC_KASAN_NOREDZONE | ZC_PERCPU)) {
redzone_tmp = 0;
} else if ((size & PAGE_MASK) == 0) {
if (size != PAGE_SIZE && (flags & ZC_ALIGNMENT_REQUIRED)) {
panic("zone_create: zone %s can't provide more than PAGE_SIZE"
"alignment", name);
}
redzone_tmp = PAGE_SIZE;
} else if (flags & ZC_ALIGNMENT_REQUIRED) {
redzone_tmp = 0;
} else {
redzone_tmp = KASAN_GUARD_SIZE;
}
size += redzone_tmp * 2;
if (redzone) {
*redzone = redzone_tmp;
}
#endif
return size;
}
/*
* Returns the allocation chunk size that has least framentation
*/
static vm_size_t
zone_get_min_alloc_granule(
vm_size_t elem_size,
zone_create_flags_t flags)
{
vm_size_t alloc_granule = PAGE_SIZE;
if (flags & ZC_PERCPU) {
alloc_granule = PAGE_SIZE * zpercpu_count();
if (PAGE_SIZE % elem_size > 256) {
panic("zone_create: per-cpu zone has too much fragmentation");
}
} else if ((elem_size & PAGE_MASK) == 0) {
/* zero fragmentation by definition */
alloc_granule = elem_size;
} else if (alloc_granule % elem_size == 0) {
/* zero fragmentation by definition */
} else {
vm_size_t frag = (alloc_granule % elem_size) * 100 / alloc_granule;
vm_size_t alloc_tmp = PAGE_SIZE;
while ((alloc_tmp += PAGE_SIZE) <= ZONE_MAX_ALLOC_SIZE) {
vm_size_t frag_tmp = (alloc_tmp % elem_size) * 100 / alloc_tmp;
if (frag_tmp < frag) {
frag = frag_tmp;
alloc_granule = alloc_tmp;
}
}
}
return alloc_granule;
}
vm_size_t
zone_get_foreign_alloc_size(
const char *name __unused,
vm_size_t elem_size,
zone_create_flags_t flags,
uint16_t min_pages)
{
vm_size_t adjusted_size = zone_elem_adjust_size(name, elem_size, flags,
NULL);
vm_size_t alloc_granule = zone_get_min_alloc_granule(adjusted_size,
flags);
vm_size_t min_size = min_pages * PAGE_SIZE;
/*
* Round up min_size to a multiple of alloc_granule
*/
return ((min_size + alloc_granule - 1) / alloc_granule)
* alloc_granule;
}
zone_t
zone_create_ext(
const char *name,
vm_size_t size,
zone_create_flags_t flags,
zone_id_t zid,
void (^extra_setup)(zone_t))
{
vm_size_t alloc;
uint32_t redzone;
zone_t z;
if (size > ZONE_MAX_ALLOC_SIZE) {
panic("zone_create: element size too large: %zd", (size_t)size);
}
if (size < 2 * sizeof(vm_size_t)) {
/* Elements are too small for kasan. */
flags |= ZC_KASAN_NOQUARANTINE | ZC_KASAN_NOREDZONE;
}
size = zone_elem_adjust_size(name, size, flags, &redzone);
/*
* Allocate the zone slot, return early if we found an older match.
*/
z = zone_create_find(name, size, flags, &zid);
if (__improbable(z->z_self)) {
/* We found a zone to reuse */
return z;
}
/*
* Initialize the zone properly.
*/
/*
* If the kernel is post lockdown, copy the zone name passed in.
* Else simply maintain a pointer to the name string as it can only
* be a core XNU zone (no unloadable kext exists before lockdown).
*/
if (startup_phase >= STARTUP_SUB_LOCKDOWN) {
size_t nsz = MIN(strlen(name) + 1, MACH_ZONE_NAME_MAX_LEN);
char *buf = zalloc_permanent(nsz, ZALIGN_NONE);
strlcpy(buf, name, nsz);
z->z_name = buf;
} else {
z->z_name = name;
}
if (__probable(zone_array[ZONE_ID_PERCPU_PERMANENT].z_self)) {
z->z_stats = zalloc_percpu_permanent_type(struct zone_stats);
} else {
/*
* zone_init() hasn't run yet, use the storage provided by
* zone_stats_startup(), and zone_init() will replace it
* with the final value once the PERCPU zone exists.
*/
z->z_stats = __zpcpu_mangle_for_boot(&zone_stats_startup[zone_index(z)]);
}
alloc = zone_get_min_alloc_granule(size, flags);
if (flags & ZC_KALLOC_HEAP) {
size_t rem = (alloc % size) / (alloc / size);
/*
* Try to grow the elements size and spread them more if the remaining
* space is large enough.
*/
size += rem & ~(KALLOC_MINALIGN - 1);
}
z->z_elem_size = (uint16_t)size;
z->z_chunk_pages = (uint16_t)atop(alloc);
if (flags & ZC_PERCPU) {
z->z_chunk_elems = (uint16_t)(PAGE_SIZE / z->z_elem_size);
} else {
z->z_chunk_elems = (uint16_t)(alloc / z->z_elem_size);
}
if (zone_element_idx(zone_element_encode(0,
z->z_chunk_elems - 1, ZPM_AUTO)) != z->z_chunk_elems - 1) {
panic("zone_element_encode doesn't work for zone [%s]", name);
}
#if KASAN_ZALLOC
z->z_kasan_redzone = redzone;
if (strncmp(name, "fakestack.", sizeof("fakestack.") - 1) == 0) {
z->kasan_fakestacks = true;
}
#endif
/*
* Handle KPI flags
*/
#if __LP64__
if (flags & ZC_SEQUESTER) {
z->z_va_sequester = true;
}
#endif
/* ZC_CACHING applied after all configuration is done */
if (flags & ZC_NOCACHING) {
z->z_nocaching = true;
}
if (flags & ZC_PERCPU) {
/*
* ZC_ZFREE_CLEARMEM is forced because per-cpu zones allow for
* pointer-sized allocations which poisoning doesn't support.
*/
zone_create_assert_not_both(name, flags, ZC_PERCPU, ZC_ALLOW_FOREIGN);
z->z_percpu = true;
z->gzalloc_exempt = true;
z->z_free_zeroes = true;
}
if (flags & ZC_ZFREE_CLEARMEM) {
z->z_free_zeroes = true;
}
if (flags & ZC_NOGC) {
z->collectable = false;
}
if (flags & ZC_NOENCRYPT) {
z->z_noencrypt = true;
}
if (flags & ZC_ALIGNMENT_REQUIRED) {
z->alignment_required = true;
}
if (flags & ZC_NOGZALLOC) {
z->gzalloc_exempt = true;
}
if (flags & ZC_NOCALLOUT) {
z->no_callout = true;
}
if (flags & ZC_DESTRUCTIBLE) {
zone_create_assert_not_both(name, flags, ZC_DESTRUCTIBLE, ZC_ALLOW_FOREIGN);
z->z_destructible = true;
}
/*
* Handle Internal flags
*/
if (flags & ZC_ALLOW_FOREIGN) {
z->z_allows_foreign = true;
}
if ((ZSECURITY_OPTIONS_SUBMAP_USER_DATA & zsecurity_options) &&
(flags & ZC_DATA_BUFFERS)) {
z->z_submap_idx = Z_SUBMAP_IDX_BAG_OF_BYTES;
}
if (flags & ZC_KASAN_NOQUARANTINE) {
z->kasan_noquarantine = true;
}
/* ZC_KASAN_NOREDZONE already handled */
/*
* Then if there's extra tuning, do it
*/
if (extra_setup) {
extra_setup(z);
}
/*
* Configure debugging features
*/
#if CONFIG_GZALLOC
gzalloc_zone_init(z); /* might set z->gzalloc_tracked */
if (z->gzalloc_tracked) {
z->z_nocaching = true;
}
#endif
#if ZONE_ENABLE_LOGGING
if (!z->gzalloc_tracked && num_zones_logged < max_num_zones_to_log) {
/*
* Check for and set up zone leak detection if requested via boot-args.
* might set z->zone_logging
*/
zone_setup_logging(z);
}
#endif /* ZONE_ENABLE_LOGGING */
#if VM_MAX_TAG_ZONES
if (!z->gzalloc_tracked && z->kalloc_heap && zone_tagging_on) {
static int tag_zone_index;
vm_offset_t esize = zone_elem_size(z);
z->tags = true;
z->tags_inline = (((page_size + esize - 1) / esize) <=
(sizeof(uint32_t) / sizeof(uint16_t)));
z->tag_zone_index = os_atomic_inc_orig(&tag_zone_index, relaxed);
assert(z->tag_zone_index < VM_MAX_TAG_ZONES);
}
#endif
/*
* Finally, fixup properties based on security policies, boot-args, ...
*/
if ((ZSECURITY_OPTIONS_SUBMAP_USER_DATA & zsecurity_options) &&
z->kalloc_heap == KHEAP_ID_DATA_BUFFERS) {
z->z_submap_idx = Z_SUBMAP_IDX_BAG_OF_BYTES;
}
#if __LP64__
if ((ZSECURITY_OPTIONS_SEQUESTER & zsecurity_options) &&
(flags & ZC_NOSEQUESTER) == 0 &&
z->z_submap_idx == Z_SUBMAP_IDX_GENERAL) {
z->z_va_sequester = true;
}
#endif
/*
* Clear entire element for non data zones and upto zp_min_size for
* data zones.
*/
if (z->z_submap_idx != Z_SUBMAP_IDX_BAG_OF_BYTES) {
z->z_free_zeroes = true;
} else if (size <= zp_min_size) {
z->z_free_zeroes = true;
}
if ((flags & ZC_CACHING) && !z->z_nocaching) {
/*
* If zcache hasn't been initialized yet, remember our decision,
*
* zone_enable_caching() will be called again by
* zcache_bootstrap(), while the system is still single
* threaded, to build the missing caches.
*/
if (__probable(zc_magazine_zone)) {
zone_enable_caching(z);
} else {
z->z_pcpu_cache =
__zpcpu_mangle_for_boot(&zone_cache_startup[zid]);
}
}
if (zp_factor != 0 && !z->z_free_zeroes) {
if (__probable(zone_array[ZONE_ID_PERCPU_PERMANENT].z_self)) {
zpercpu_foreach(zs, z->z_stats) {
zs->zs_poison_seqno = zone_poison_count_init(z);
}
} else {
zone_stats_startup[zid].zs_poison_seqno =
zone_poison_count_init(z);
}
}
zone_lock(z);
z->z_self = z;
zone_unlock(z);
return z;
}
__startup_func
void
zone_create_startup(struct zone_create_startup_spec *spec)
{
*spec->z_var = zone_create_ext(spec->z_name, spec->z_size,
spec->z_flags, spec->z_zid, spec->z_setup);
}
/*
* The 4 first field of a zone_view and a zone alias, so that the zone_or_view_t
* union works. trust but verify.
*/
#define zalloc_check_zov_alias(f1, f2) \
static_assert(offsetof(struct zone, f1) == offsetof(struct zone_view, f2))
zalloc_check_zov_alias(z_self, zv_zone);
zalloc_check_zov_alias(z_stats, zv_stats);
zalloc_check_zov_alias(z_name, zv_name);
zalloc_check_zov_alias(z_views, zv_next);
#undef zalloc_check_zov_alias
__startup_func
void
zone_view_startup_init(struct zone_view_startup_spec *spec)
{
struct kalloc_heap *heap = NULL;
zone_view_t zv = spec->zv_view;
zone_t z;
switch (spec->zv_heapid) {
case KHEAP_ID_DEFAULT:
heap = KHEAP_DEFAULT;
break;
case KHEAP_ID_DATA_BUFFERS:
heap = KHEAP_DATA_BUFFERS;
break;
case KHEAP_ID_KEXT:
heap = KHEAP_KEXT;
break;
default:
heap = NULL;
}
if (heap) {
z = kalloc_heap_zone_for_size(heap, spec->zv_size);
assert(z);
} else {
z = spec->zv_zone;
assert(spec->zv_size <= zone_elem_size(z));
}
zv->zv_zone = z;
zv->zv_stats = zalloc_percpu_permanent_type(struct zone_stats);
zv->zv_next = z->z_views;
if (z->z_views == NULL && z->kalloc_heap == KHEAP_ID_NONE) {
/*
* count the raw view for zones not in a heap,
* kalloc_heap_init() already counts it for its members.
*/
zone_view_count += 2;
} else {
zone_view_count += 1;
}
z->z_views = zv;
}
zone_t
zone_create(
const char *name,
vm_size_t size,
zone_create_flags_t flags)
{
return zone_create_ext(name, size, flags, ZONE_ID_ANY, NULL);
}
zone_t
zinit(
vm_size_t size, /* the size of an element */
vm_size_t max, /* maximum memory to use */
vm_size_t alloc __unused, /* allocation size */
const char *name) /* a name for the zone */
{
zone_t z = zone_create(name, size, ZC_DESTRUCTIBLE);
z->z_wired_max = zone_alloc_pages_for_nelems(z, max / size);
return z;
}
void
zdestroy(zone_t z)
{
unsigned int zindex = zone_index(z);
current_thread()->options |= TH_OPT_ZONE_PRIV;
lck_mtx_lock(&zone_gc_lock);
zone_reclaim(z, ZONE_RECLAIM_DESTROY);
lck_mtx_unlock(&zone_gc_lock);
current_thread()->options &= ~TH_OPT_ZONE_PRIV;
#if CONFIG_GZALLOC
if (__improbable(z->gzalloc_tracked)) {
/* If the zone is gzalloc managed dump all the elements in the free cache */
gzalloc_empty_free_cache(z);
}
#endif
zone_lock(z);
while (!zone_pva_is_null(z->z_pageq_va)) {
struct zone_page_metadata *meta;
vm_offset_t free_addr;
zone_counter_sub(z, z_va_cur, z->z_percpu ? 1 : z->z_chunk_pages);
meta = zone_meta_queue_pop_native(z, &z->z_pageq_va, &free_addr);
assert(meta->zm_chunk_len <= ZM_CHUNK_LEN_MAX);
bzero(meta, sizeof(*meta) * z->z_chunk_pages);
zone_unlock(z);
kmem_free(zone_submap(z), free_addr, ptoa(z->z_chunk_pages));
zone_lock(z);
}
#if !KASAN_ZALLOC
/* Assert that all counts are zero */
if (z->z_elems_avail || z->z_elems_free ||
zone_size_wired(z) || z->z_va_cur) {
panic("zdestroy: Zone %s%s isn't empty at zdestroy() time",
zone_heap_name(z), z->z_name);
}
/* consistency check: make sure everything is indeed empty */
assert(zone_pva_is_null(z->z_pageq_empty));
assert(zone_pva_is_null(z->z_pageq_partial));
assert(zone_pva_is_null(z->z_pageq_full));
assert(zone_pva_is_null(z->z_pageq_va));
#endif
zone_unlock(z);
simple_lock(&all_zones_lock, &zone_locks_grp);
assert(!bitmap_test(zone_destroyed_bitmap, zindex));
/* Mark the zone as empty in the bitmap */
bitmap_set(zone_destroyed_bitmap, zindex);
num_zones_in_use--;
assert(num_zones_in_use > 0);
simple_unlock(&all_zones_lock);
}
#endif /* !ZALLOC_TEST */
#pragma mark zalloc module init
#if !ZALLOC_TEST
/*
* Initialize the "zone of zones" which uses fixed memory allocated
* earlier in memory initialization. zone_bootstrap is called
* before zone_init.
*/
__startup_func
void
zone_bootstrap(void)
{
/* Validate struct zone_packed_virtual_address expectations */
static_assert((intptr_t)VM_MIN_KERNEL_ADDRESS < 0, "the top bit must be 1");
if (VM_KERNEL_POINTER_SIGNIFICANT_BITS - PAGE_SHIFT > 31) {
panic("zone_pva_t can't pack a kernel page address in 31 bits");
}
zpercpu_early_count = ml_early_cpu_max_number() + 1;
/* Set up zone element poisoning */
zp_bootstrap();
/*
* the KASAN quarantine for kalloc doesn't understand heaps
* and trips the heap confusion panics. At the end of the day,
* all these security measures are double duty with KASAN.
*
* On 32bit kernels, these protections are just too expensive.
*/
#if !defined(__LP64__) || KASAN_ZALLOC
zsecurity_options &= ~ZSECURITY_OPTIONS_SEQUESTER;
zsecurity_options &= ~ZSECURITY_OPTIONS_SUBMAP_USER_DATA;
zsecurity_options &= ~ZSECURITY_OPTIONS_SEQUESTER_KEXT_KALLOC;
#endif
thread_call_setup_with_options(&zone_expand_callout,
zone_expand_async, NULL, THREAD_CALL_PRIORITY_HIGH,
THREAD_CALL_OPTIONS_ONCE);
thread_call_setup_with_options(&zone_defrag_callout,
zone_defrag_async, NULL, THREAD_CALL_PRIORITY_USER,
THREAD_CALL_OPTIONS_ONCE);
}
#if __LP64__
#if ARM_LARGE_MEMORY || __x86_64__
#define ZONE_MAP_VIRTUAL_SIZE_LP64 (128ULL * 1024ULL * 1024 * 1024)
#else
#define ZONE_MAP_VIRTUAL_SIZE_LP64 (32ULL * 1024ULL * 1024 * 1024)
#endif
#endif /* __LP64__ */
#define ZONE_GUARD_SIZE (64UL << 10)
#if __LP64__
static inline vm_offset_t
zone_restricted_va_max(void)
{
vm_offset_t compressor_max = VM_PACKING_MAX_PACKABLE(C_SLOT_PACKED_PTR);
vm_offset_t vm_page_max = VM_PACKING_MAX_PACKABLE(VM_PAGE_PACKED_PTR);
return trunc_page(MIN(compressor_max, vm_page_max));
}
#endif
__startup_func
static void
zone_tunables_fixup(void)
{
if (zone_map_jetsam_limit == 0 || zone_map_jetsam_limit > 100) {
zone_map_jetsam_limit = ZONE_MAP_JETSAM_LIMIT_DEFAULT;
}
if (zc_magazine_size > PAGE_SIZE / ZONE_MIN_ELEM_SIZE) {
zc_magazine_size = (uint16_t)(PAGE_SIZE / ZONE_MIN_ELEM_SIZE);
}
}
STARTUP(TUNABLES, STARTUP_RANK_MIDDLE, zone_tunables_fixup);
__startup_func
static vm_size_t
zone_phys_size_max(void)
{
vm_size_t zsize;
vm_size_t zsizearg;
if (PE_parse_boot_argn("zsize", &zsizearg, sizeof(zsizearg))) {
zsize = zsizearg * (1024ULL * 1024);
} else {
/* Set target zone size as 1/4 of physical memory */
zsize = (vm_size_t)(sane_size >> 2);
#if defined(__LP64__)
zsize += zsize >> 1;
#endif /* __LP64__ */
}
if (zsize < CONFIG_ZONE_MAP_MIN) {
zsize = CONFIG_ZONE_MAP_MIN; /* Clamp to min */
}
if (zsize > sane_size >> 1) {
zsize = (vm_size_t)(sane_size >> 1); /* Clamp to half of RAM max */
}
if (zsizearg == 0 && zsize > ZONE_MAP_MAX) {
/* if zsize boot-arg not present and zsize exceeds platform maximum, clip zsize */
printf("NOTE: zonemap size reduced from 0x%lx to 0x%lx\n",
(uintptr_t)zsize, (uintptr_t)ZONE_MAP_MAX);
zsize = ZONE_MAP_MAX;
}
return (vm_size_t)trunc_page(zsize);
}
__options_decl(zone_init_allocate_flags_t, unsigned, {
ZIA_NONE = 0x00000000,
ZIA_REPLACE = 0x00000001, /* replace a previous non permanent range */
ZIA_RANDOM = 0x00000002, /* place at a random address */
ZIA_PERMANENT = 0x00000004, /* permanent allocation */
ZIA_GUARD = 0x00000008, /* will be used as a guard */
});
__startup_func
static struct zone_map_range
zone_init_allocate_va(vm_map_address_t addr, vm_size_t size,
zone_init_allocate_flags_t flags)
{
vm_map_kernel_flags_t vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
int vm_alloc_flags = 0;
struct zone_map_range r;
kern_return_t kr;
if (flags & ZIA_REPLACE) {
vm_alloc_flags |= VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE;
} else {
vm_alloc_flags |= VM_FLAGS_ANYWHERE;
}
if (flags & ZIA_RANDOM) {
vm_alloc_flags |= VM_FLAGS_RANDOM_ADDR;
}
if (flags & ZIA_PERMANENT) {
vmk_flags.vmkf_permanent = true;
}
vm_object_reference(kernel_object);
kr = vm_map_enter(kernel_map, &addr, size, 0,
vm_alloc_flags, vmk_flags, VM_KERN_MEMORY_ZONE,
kernel_object, 0, FALSE,
(flags & ZIA_GUARD) ? VM_PROT_NONE : VM_PROT_DEFAULT,
(flags & ZIA_GUARD) ? VM_PROT_NONE : VM_PROT_DEFAULT,
VM_INHERIT_NONE);
if (KERN_SUCCESS != kr) {
panic("vm_map_enter(0x%zx) failed: %d", (size_t)size, kr);
}
r.min_address = (vm_offset_t)addr;
r.max_address = (vm_offset_t)addr + size;
return r;
}
__startup_func
static void
zone_submap_init(
vm_offset_t *submap_min,
unsigned idx,
uint64_t zone_sub_map_numer,
uint64_t *remaining_denom,
vm_offset_t *remaining_size,
vm_size_t guard_size)
{
vm_offset_t submap_start, submap_end;
vm_size_t submap_size;
vm_map_t submap;
kern_return_t kr;
submap_size = trunc_page(zone_sub_map_numer * *remaining_size /
*remaining_denom);
submap_start = *submap_min;
submap_end = submap_start + submap_size;
#if defined(__LP64__)
if (idx == Z_SUBMAP_IDX_VA_RESTRICTED) {
vm_offset_t restricted_va_max = zone_restricted_va_max();
if (submap_end > restricted_va_max) {
#if DEBUG || DEVELOPMENT
printf("zone_init: submap[%d] clipped to %zdM of %zdM\n", idx,
(size_t)(restricted_va_max - submap_start) >> 20,
(size_t)submap_size >> 20);
#endif /* DEBUG || DEVELOPMENT */
guard_size += submap_end - restricted_va_max;
*remaining_size -= submap_end - restricted_va_max;
submap_end = restricted_va_max;
submap_size = restricted_va_max - submap_start;
}
vm_packing_verify_range("vm_compressor",
submap_start, submap_end, VM_PACKING_PARAMS(C_SLOT_PACKED_PTR));
vm_packing_verify_range("vm_page",
submap_start, submap_end, VM_PACKING_PARAMS(VM_PAGE_PACKED_PTR));
}
#endif /* defined(__LP64__) */
vm_map_kernel_flags_t vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
vmk_flags.vmkf_permanent = TRUE;
kr = kmem_suballoc(kernel_map, submap_min, submap_size,
FALSE, VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE, vmk_flags,
VM_KERN_MEMORY_ZONE, &submap);
if (kr != KERN_SUCCESS) {
panic("kmem_suballoc(kernel_map[%d] %p:%p) failed: %d",
idx, (void *)submap_start, (void *)submap_end, kr);
}
#if DEBUG || DEVELOPMENT
printf("zone_init: submap[%d] %p:%p (%zuM)\n",
idx, (void *)submap_start, (void *)submap_end,
(size_t)submap_size >> 20);
#endif /* DEBUG || DEVELOPMENT */
zone_init_allocate_va(submap_end, guard_size,
ZIA_PERMANENT | ZIA_GUARD | ZIA_REPLACE);
zone_submaps[idx] = submap;
*submap_min = submap_end + guard_size;
*remaining_size -= submap_size;
*remaining_denom -= zone_sub_map_numer;
}
/*
* Allocate metadata array and migrate foreign initial metadata.
*
* So that foreign pages and native pages have the same scheme,
* we allocate VA space that covers both foreign and native pages.
*/
__startup_func
static void
zone_metadata_init(void)
{
struct zone_map_range r0 = zone_info.zi_map_range[0];
struct zone_map_range r1 = zone_info.zi_map_range[1];
struct zone_map_range mr, br;
vm_size_t meta_size, bits_size, foreign_base;
vm_offset_t hstart, hend;
if (r0.min_address > r1.min_address) {
r0 = zone_info.zi_map_range[1];
r1 = zone_info.zi_map_range[0];
}
meta_size = round_page(atop(r1.max_address - r0.min_address) *
sizeof(struct zone_page_metadata)) + ZONE_GUARD_SIZE * 2;
/*
* Allocations can't be smaller than 8 bytes, which is 128b / 16B per 1k
* of physical memory (16M per 1G).
*
* Let's preallocate for the worst to avoid weird panics.
*/
bits_size = round_page(16 * (ptoa(zone_phys_mapped_max_pages) >> 10));
/*
* Compute the size of the "hole" in the middle of the range.
*
* If it is smaller than 256k, just leave it be, with this layout:
*
* [G][ r0 meta ][ hole ][ r1 meta ][ bits ][G]
*
* else punch a hole with guard pages around the hole, and place the
* bits in the hole if it fits, or after r1 otherwise, yielding either
* of the following layouts:
*
* |__________________hend____________|
* |__hstart_| |
* [G][ r0 meta ][ bits ][G]..........[G][ r1 meta ][G]
* [G][ r0 meta ][G]..................[G][ r1 meta ][ bits ][G]
*/
hstart = round_page(atop(r0.max_address - r0.min_address) *
sizeof(struct zone_page_metadata));
hend = trunc_page(atop(r1.min_address - r0.min_address) *
sizeof(struct zone_page_metadata));
if (hstart >= hend || hend - hstart < (256ul << 10)) {
mr = zone_init_allocate_va(0, meta_size + bits_size,
ZIA_PERMANENT | ZIA_RANDOM);
mr.min_address += ZONE_GUARD_SIZE;
mr.max_address -= ZONE_GUARD_SIZE;
br.max_address = mr.max_address;
mr.max_address -= bits_size;
br.min_address = mr.max_address;
#if DEBUG || DEVELOPMENT
printf("zone_init: metadata %p:%p (%zuK)\n",
(void *)mr.min_address, (void *)mr.max_address,
(size_t)zone_range_size(&mr) >> 10);
printf("zone_init: metabits %p:%p (%zuK)\n",
(void *)br.min_address, (void *)br.max_address,
(size_t)zone_range_size(&br) >> 10);
#endif /* DEBUG || DEVELOPMENT */
} else {
vm_size_t size, alloc_size = meta_size;
vm_offset_t base;
bool bits_in_middle = true;
if (hend - hstart - 2 * ZONE_GUARD_SIZE < bits_size) {
alloc_size += bits_size;
bits_in_middle = false;
}
mr = zone_init_allocate_va(0, alloc_size, ZIA_RANDOM);
base = mr.min_address;
size = ZONE_GUARD_SIZE + hstart + ZONE_GUARD_SIZE;
if (bits_in_middle) {
size += bits_size;
br.min_address = base + ZONE_GUARD_SIZE + hstart;
br.max_address = br.min_address + bits_size;
}
zone_init_allocate_va(base, size, ZIA_PERMANENT | ZIA_REPLACE);
base += size;
size = mr.min_address + hend - base;
kmem_free(kernel_map, base, size);
base = mr.min_address + hend;
size = mr.max_address - base;
zone_init_allocate_va(base, size, ZIA_PERMANENT | ZIA_REPLACE);
mr.min_address += ZONE_GUARD_SIZE;
mr.max_address -= ZONE_GUARD_SIZE;
if (!bits_in_middle) {
br.max_address = mr.max_address;
mr.max_address -= bits_size;
br.min_address = mr.max_address;
}
#if DEBUG || DEVELOPMENT
printf("zone_init: metadata0 %p:%p (%zuK)\n",
(void *)mr.min_address, (void *)(mr.min_address + hstart),
(size_t)hstart >> 10);
printf("zone_init: metadata1 %p:%p (%zuK)\n",
(void *)(mr.min_address + hend), (void *)mr.max_address,
(size_t)(zone_range_size(&mr) - hend) >> 10);
printf("zone_init: metabits %p:%p (%zuK)\n",
(void *)br.min_address, (void *)br.max_address,
(size_t)zone_range_size(&br) >> 10);
#endif /* DEBUG || DEVELOPMENT */
}
br.min_address = (br.min_address + ZBA_CHUNK_SIZE - 1) & -ZBA_CHUNK_SIZE;
br.max_address = br.max_address & -ZBA_CHUNK_SIZE;
zone_info.zi_meta_range = mr;
zone_info.zi_bits_range = br;
/*
* Migrate the original static metadata into its new location.
*/
zone_info.zi_meta_base = (struct zone_page_metadata *)mr.min_address -
zone_pva_from_addr(r0.min_address).packed_address;
foreign_base = zone_info.zi_map_range[ZONE_ADDR_FOREIGN].min_address;
zone_meta_populate(foreign_base, zone_foreign_size());
memcpy(zone_meta_from_addr(foreign_base),
zone_foreign_meta_array_startup,
atop(zone_foreign_size()) * sizeof(struct zone_page_metadata));
zba_populate(0);
memcpy(zba_base_header(), zba_chunk_startup,
sizeof(zba_chunk_startup));
}
/* Global initialization of Zone Allocator.
* Runs after zone_bootstrap.
*/
__startup_func
static void
zone_init(void)
{
vm_size_t zone_map_size;
vm_size_t remaining_size;
vm_offset_t submap_min = 0;
uint64_t denom = 0;
uint64_t submap_ratios[Z_SUBMAP_IDX_COUNT] = {
#ifdef __LP64__
[Z_SUBMAP_IDX_VA_RESTRICTED] = 20,
#else
[Z_SUBMAP_IDX_VA_RESERVE] = 10,
#endif /* defined(__LP64__) */
[Z_SUBMAP_IDX_GENERAL] = 40,
[Z_SUBMAP_IDX_BAG_OF_BYTES] = 40,
};
if (ZSECURITY_OPTIONS_SUBMAP_USER_DATA & zsecurity_options) {
zone_last_submap_idx = Z_SUBMAP_IDX_BAG_OF_BYTES;
} else {
zone_last_submap_idx = Z_SUBMAP_IDX_GENERAL;
}
zone_phys_mapped_max_pages = (uint32_t)atop(zone_phys_size_max());
for (unsigned idx = 0; idx <= zone_last_submap_idx; idx++) {
#if DEBUG || DEVELOPMENT
char submap_name[1 + sizeof("submap")];
snprintf(submap_name, sizeof(submap_name), "submap%d", idx);
PE_parse_boot_argn(submap_name, &submap_ratios[idx], sizeof(uint64_t));
#endif
denom += submap_ratios[idx];
}
#if __LP64__
zone_map_size = ZONE_MAP_VIRTUAL_SIZE_LP64;
#else
zone_map_size = ptoa(zone_phys_mapped_max_pages *
(denom + submap_ratios[Z_SUBMAP_IDX_VA_RESERVE]) / denom);
#endif
remaining_size = zone_map_size -
ZONE_GUARD_SIZE * (zone_last_submap_idx + 1);
/*
* And now allocate the various pieces of VA and submaps.
*
* Make a first allocation of contiguous VA, that we'll deallocate,
* and we'll carve-out memory in that range again linearly.
* The kernel is stil single threaded at this stage.
*/
struct zone_map_range *map_range =
&zone_info.zi_map_range[ZONE_ADDR_NATIVE];
*map_range = zone_init_allocate_va(0, zone_map_size, ZIA_NONE);
submap_min = map_range->min_address;
/*
* Allocate the submaps
*/
for (unsigned idx = 0; idx <= zone_last_submap_idx; idx++) {
zone_submap_init(&submap_min, idx, submap_ratios[idx],
&denom, &remaining_size, ZONE_GUARD_SIZE);
}
assert(submap_min == map_range->max_address);
zone_metadata_init();
#if VM_MAX_TAG_ZONES
if (zone_tagging_on) {
zone_tagging_init(zone_map_size);
}
#endif
#if CONFIG_GZALLOC
gzalloc_init(zone_map_size);
#endif
zone_create_flags_t kma_flags = ZC_NOCACHING |
ZC_NOGC | ZC_NOENCRYPT | ZC_NOGZALLOC | ZC_NOCALLOUT |
ZC_KASAN_NOQUARANTINE | ZC_KASAN_NOREDZONE;
(void)zone_create_ext("vm.permanent", 1, kma_flags,
ZONE_ID_PERMANENT, ^(zone_t z){
z->z_permanent = true;
z->z_elem_size = 1;
#if defined(__LP64__)
z->z_submap_idx = Z_SUBMAP_IDX_VA_RESTRICTED;
#endif
});
(void)zone_create_ext("vm.permanent.percpu", 1, kma_flags | ZC_PERCPU,
ZONE_ID_PERCPU_PERMANENT, ^(zone_t z){
z->z_permanent = true;
z->z_elem_size = 1;
#if defined(__LP64__)
z->z_submap_idx = Z_SUBMAP_IDX_VA_RESTRICTED;
#endif
});
/*
* Now migrate the startup statistics into their final storage.
*/
int cpu = cpu_number();
zone_index_foreach(idx) {
zone_t tz = &zone_array[idx];
if (tz->z_stats == __zpcpu_mangle_for_boot(&zone_stats_startup[idx])) {
zone_stats_t zs = zalloc_percpu_permanent_type(struct zone_stats);
*zpercpu_get_cpu(zs, cpu) = *zpercpu_get_cpu(tz->z_stats, cpu);
tz->z_stats = zs;
#if ZONE_ENABLE_LOGGING
if (tz->zone_logging && !tz->zlog_btlog) {
zone_enable_logging(tz);
}
#endif /* ZONE_ENABLE_LOGGING */
}
}
#if CONFIG_ZLEAKS
/*
* Initialize the zone leak monitor
*/
zleak_init(zone_map_size);
#endif /* CONFIG_ZLEAKS */
#if VM_MAX_TAG_ZONES
if (zone_tagging_on) {
vm_allocation_zones_init();
}
#endif
}
STARTUP(ZALLOC, STARTUP_RANK_FIRST, zone_init);
__startup_func
static void
zone_cache_bootstrap(void)
{
zone_t magzone;
magzone = zone_create("zcc_magazine_zone", sizeof(struct zone_magazine) +
zc_mag_size() * sizeof(zone_element_t),
ZC_NOGZALLOC | ZC_KASAN_NOREDZONE | ZC_KASAN_NOQUARANTINE |
ZC_SEQUESTER | ZC_CACHING | ZC_ZFREE_CLEARMEM);
magzone->z_elems_rsv = (uint16_t)(2 * zpercpu_count());
os_atomic_store(&zc_magazine_zone, magzone, compiler_acq_rel);
/*
* Now that we are initialized, we can enable zone caching for zones that
* were made before zcache_bootstrap() was called.
*
* The system is still single threaded so we don't need to take the lock.
*/
zone_index_foreach(i) {
zone_t z = &zone_array[i];
if (z->z_pcpu_cache) {
z->z_pcpu_cache = NULL;
zone_enable_caching(z);
}
}
}
STARTUP(ZALLOC, STARTUP_RANK_FOURTH, zone_cache_bootstrap);
void
zalloc_first_proc_made(void)
{
zone_caching_disabled = 0;
}
__startup_func
vm_offset_t
zone_foreign_mem_init(vm_size_t size)
{
vm_offset_t mem;
if (atop(size) > ZONE_FOREIGN_META_INLINE_COUNT) {
panic("ZONE_FOREIGN_META_INLINE_COUNT has become too small: "
"%d > %d", (int)atop(size), ZONE_FOREIGN_META_INLINE_COUNT);
}
mem = (vm_offset_t)pmap_steal_memory(size);
zone_info.zi_meta_base = zone_foreign_meta_array_startup -
zone_pva_from_addr(mem).packed_address;
zone_info.zi_map_range[ZONE_ADDR_FOREIGN].min_address = mem;
zone_info.zi_map_range[ZONE_ADDR_FOREIGN].max_address = mem + size;
zone_info.zi_bits_range = (struct zone_map_range){
.min_address = (vm_offset_t)zba_chunk_startup,
.max_address = (vm_offset_t)zba_chunk_startup +
sizeof(zba_chunk_startup),
};
zba_init_chunk(0);
return mem;
}
#endif /* !ZALLOC_TEST */
#pragma mark - tests
#if DEBUG || DEVELOPMENT
/*
* Used for sysctl kern.run_zone_test which is not thread-safe. Ensure only one
* thread goes through at a time. Or we can end up with multiple test zones (if
* a second zinit() comes through before zdestroy()), which could lead us to
* run out of zones.
*/
static SIMPLE_LOCK_DECLARE(zone_test_lock, 0);
static boolean_t zone_test_running = FALSE;
static zone_t test_zone_ptr = NULL;
static uintptr_t *
zone_copy_allocations(zone_t z, uintptr_t *elems, zone_pva_t page_index)
{
vm_offset_t elem_size = zone_elem_size(z);
vm_offset_t base;
struct zone_page_metadata *meta;
while (!zone_pva_is_null(page_index)) {
base = zone_pva_to_addr(page_index);
meta = zone_pva_to_meta(page_index);
if (meta->zm_inline_bitmap) {
for (size_t i = 0; i < meta->zm_chunk_len; i++) {
uint32_t map = meta[i].zm_bitmap;
for (; map; map &= map - 1) {
*elems++ = INSTANCE_PUT(base +
elem_size * __builtin_clz(map));
}
base += elem_size * 32;
}
} else {
uint32_t order = zba_bits_ref_order(meta->zm_bitmap);
bitmap_t *bits = zba_bits_ref_ptr(meta->zm_bitmap);
for (size_t i = 0; i < (1u << order); i++) {
uint64_t map = bits[i];
for (; map; map &= map - 1) {
*elems++ = INSTANCE_PUT(base +
elem_size * __builtin_clzll(map));
}
base += elem_size * 64;
}
}
page_index = meta->zm_page_next;
}
return elems;
}
kern_return_t
zone_leaks(const char * zoneName, uint32_t nameLen, leak_site_proc proc, void * refCon)
{
uintptr_t zbt[MAX_ZTRACE_DEPTH];
zone_t zone = NULL;
uintptr_t * array;
uintptr_t * next;
uintptr_t element, bt;
uint32_t idx, count, found;
uint32_t btidx, btcount, nobtcount, btfound;
uint32_t elemSize;
size_t maxElems;
kern_return_t kr;
zone_foreach(z) {
if (!strncmp(zoneName, z->z_name, nameLen)) {
zone = z;
break;
}
}
if (zone == NULL) {
return KERN_INVALID_NAME;
}
elemSize = (uint32_t)zone_elem_size(zone);
maxElems = (zone->z_elems_avail + 1) & ~1ul;
if ((ptoa(zone->z_percpu ? 1 : zone->z_chunk_pages) % elemSize) &&
!zone_leaks_scan_enable) {
return KERN_INVALID_CAPABILITY;
}
kr = kmem_alloc_kobject(kernel_map, (vm_offset_t *) &array,
maxElems * sizeof(uintptr_t), VM_KERN_MEMORY_DIAG);
if (KERN_SUCCESS != kr) {
return kr;
}
zone_lock(zone);
next = array;
next = zone_copy_allocations(zone, next, zone->z_pageq_partial);
next = zone_copy_allocations(zone, next, zone->z_pageq_full);
count = (uint32_t)(next - array);
zone_unlock(zone);
zone_leaks_scan(array, count, (uint32_t)zone_elem_size(zone), &found);
assert(found <= count);
for (idx = 0; idx < count; idx++) {
element = array[idx];
if (kInstanceFlagReferenced & element) {
continue;
}
element = INSTANCE_PUT(element) & ~kInstanceFlags;
}
#if ZONE_ENABLE_LOGGING
if (zone->zlog_btlog && !corruption_debug_flag) {
// btlog_copy_backtraces_for_elements will set kInstanceFlagReferenced on elements it found
btlog_copy_backtraces_for_elements(zone->zlog_btlog, array, &count, elemSize, proc, refCon);
}
#endif /* ZONE_ENABLE_LOGGING */
for (nobtcount = idx = 0; idx < count; idx++) {
element = array[idx];
if (!element) {
continue;
}
if (kInstanceFlagReferenced & element) {
continue;
}
element = INSTANCE_PUT(element) & ~kInstanceFlags;
// see if we can find any backtrace left in the element
btcount = (typeof(btcount))(zone_elem_size(zone) / sizeof(uintptr_t));
if (btcount >= MAX_ZTRACE_DEPTH) {
btcount = MAX_ZTRACE_DEPTH - 1;
}
for (btfound = btidx = 0; btidx < btcount; btidx++) {
bt = ((uintptr_t *)element)[btcount - 1 - btidx];
if (!VM_KERNEL_IS_SLID(bt)) {
break;
}
zbt[btfound++] = bt;
}
if (btfound) {
(*proc)(refCon, 1, elemSize, &zbt[0], btfound);
} else {
nobtcount++;
}
}
if (nobtcount) {
// fake backtrace when we found nothing
zbt[0] = (uintptr_t) &zalloc;
(*proc)(refCon, nobtcount, elemSize, &zbt[0], 1);
}
kmem_free(kernel_map, (vm_offset_t) array, maxElems * sizeof(uintptr_t));
return KERN_SUCCESS;
}
boolean_t
run_zone_test(void)
{
unsigned int i = 0, max_iter = 5;
void * test_ptr;
zone_t test_zone;
zone_t test_pcpu_zone;
kern_return_t kr;
simple_lock(&zone_test_lock, &zone_locks_grp);
if (!zone_test_running) {
zone_test_running = TRUE;
} else {
simple_unlock(&zone_test_lock);
printf("run_zone_test: Test already running.\n");
return FALSE;
}
simple_unlock(&zone_test_lock);
printf("run_zone_test: Testing zinit(), zalloc(), zfree() and zdestroy() on zone \"test_zone_sysctl\"\n");
/* zinit() and zdestroy() a zone with the same name a bunch of times, verify that we get back the same zone each time */
do {
test_zone = zinit(sizeof(uint64_t), 100 * sizeof(uint64_t), sizeof(uint64_t), "test_zone_sysctl");
if (test_zone == NULL) {
printf("run_zone_test: zinit() failed\n");
return FALSE;
}
#if KASAN_ZALLOC
if (test_zone_ptr == NULL && test_zone->z_elems_free != 0) {
#else
if (test_zone->z_elems_free != 0) {
#endif
printf("run_zone_test: free count is not zero\n");
return FALSE;
}
if (test_zone_ptr == NULL) {
/* Stash the zone pointer returned on the fist zinit */
printf("run_zone_test: zone created for the first time\n");
test_zone_ptr = test_zone;
} else if (test_zone != test_zone_ptr) {
printf("run_zone_test: old zone pointer and new zone pointer don't match\n");
return FALSE;
}
test_ptr = zalloc(test_zone);
if (test_ptr == NULL) {
printf("run_zone_test: zalloc() failed\n");
return FALSE;
}
zfree(test_zone, test_ptr);
zdestroy(test_zone);
i++;
printf("run_zone_test: Iteration %d successful\n", i);
} while (i < max_iter);
/* test Z_VA_SEQUESTER */
if (zsecurity_options & ZSECURITY_OPTIONS_SEQUESTER) {
int idx, num_allocs = 8;
vm_size_t elem_size = 2 * PAGE_SIZE / num_allocs;
void *allocs[num_allocs];
void **allocs_pcpu;
vm_offset_t phys_pages = os_atomic_load(&zones_phys_page_mapped_count, relaxed);
test_zone = zone_create("test_zone_sysctl", elem_size,
ZC_DESTRUCTIBLE | ZC_SEQUESTER);
assert(test_zone);
test_pcpu_zone = zone_create("test_zone_sysctl.pcpu", sizeof(uint64_t),
ZC_DESTRUCTIBLE | ZC_SEQUESTER | ZC_PERCPU);
assert(test_pcpu_zone);
for (idx = 0; idx < num_allocs; idx++) {
allocs[idx] = zalloc(test_zone);
assert(NULL != allocs[idx]);
printf("alloc[%d] %p\n", idx, allocs[idx]);
}
for (idx = 0; idx < num_allocs; idx++) {
zfree(test_zone, allocs[idx]);
}
assert(!zone_pva_is_null(test_zone->z_pageq_empty));
kr = kernel_memory_allocate(kernel_map,
(vm_address_t *)&allocs_pcpu, PAGE_SIZE,
0, KMA_ZERO | KMA_KOBJECT, VM_KERN_MEMORY_DIAG);
assert(kr == KERN_SUCCESS);
for (idx = 0; idx < PAGE_SIZE / sizeof(uint64_t); idx++) {
allocs_pcpu[idx] = zalloc_percpu(test_pcpu_zone,
Z_WAITOK | Z_ZERO);
assert(NULL != allocs_pcpu[idx]);
}
for (idx = 0; idx < PAGE_SIZE / sizeof(uint64_t); idx++) {
zfree_percpu(test_pcpu_zone, allocs_pcpu[idx]);
}
assert(!zone_pva_is_null(test_pcpu_zone->z_pageq_empty));
printf("vm_page_wire_count %d, vm_page_free_count %d, p to v %ld%%\n",
vm_page_wire_count, vm_page_free_count,
100L * phys_pages / zone_phys_mapped_max_pages);
zone_gc(ZONE_GC_DRAIN);
printf("vm_page_wire_count %d, vm_page_free_count %d, p to v %ld%%\n",
vm_page_wire_count, vm_page_free_count,
100L * phys_pages / zone_phys_mapped_max_pages);
unsigned int allva = 0;
zone_foreach(z) {
zone_lock(z);
allva += z->z_wired_cur;
if (zone_pva_is_null(z->z_pageq_va)) {
zone_unlock(z);
continue;
}
unsigned count = 0;
uint64_t size;
zone_pva_t pg = z->z_pageq_va;
struct zone_page_metadata *page_meta;
while (pg.packed_address) {
page_meta = zone_pva_to_meta(pg);
count += z->z_percpu ? 1 : z->z_chunk_pages;
if (page_meta->zm_chunk_len == ZM_SECONDARY_PAGE) {
count -= page_meta->zm_page_index;
}
pg = page_meta->zm_page_next;
}
assert(z->z_wired_cur + count == z->z_va_cur);
size = zone_size_wired(z);
if (!size) {
size = 1;
}
printf("%s%s: seq %d, res %d, %qd %%\n",
zone_heap_name(z), z->z_name, z->z_va_cur - z->z_wired_cur,
z->z_wired_cur, zone_size_allocated(z) * 100ULL / size);
zone_unlock(z);
}
printf("total va: %d\n", allva);
assert(zone_pva_is_null(test_zone->z_pageq_empty));
assert(zone_pva_is_null(test_zone->z_pageq_partial));
assert(!zone_pva_is_null(test_zone->z_pageq_va));
assert(zone_pva_is_null(test_pcpu_zone->z_pageq_empty));
assert(zone_pva_is_null(test_pcpu_zone->z_pageq_partial));
assert(!zone_pva_is_null(test_pcpu_zone->z_pageq_va));
for (idx = 0; idx < num_allocs; idx++) {
assert(0 == pmap_find_phys(kernel_pmap, (addr64_t)(uintptr_t) allocs[idx]));
}
/* make sure the zone is still usable after a GC */
for (idx = 0; idx < num_allocs; idx++) {
allocs[idx] = zalloc(test_zone);
assert(allocs[idx]);
printf("alloc[%d] %p\n", idx, allocs[idx]);
}
assert(zone_pva_is_null(test_zone->z_pageq_va));
assert(test_zone->z_wired_cur == test_zone->z_va_cur);
for (idx = 0; idx < num_allocs; idx++) {
zfree(test_zone, allocs[idx]);
}
for (idx = 0; idx < PAGE_SIZE / sizeof(uint64_t); idx++) {
allocs_pcpu[idx] = zalloc_percpu(test_pcpu_zone,
Z_WAITOK | Z_ZERO);
assert(NULL != allocs_pcpu[idx]);
}
for (idx = 0; idx < PAGE_SIZE / sizeof(uint64_t); idx++) {
zfree_percpu(test_pcpu_zone, allocs_pcpu[idx]);
}
assert(!zone_pva_is_null(test_pcpu_zone->z_pageq_empty));
assert(zone_pva_is_null(test_pcpu_zone->z_pageq_va));
kmem_free(kernel_map, (vm_address_t)allocs_pcpu, PAGE_SIZE);
zdestroy(test_zone);
zdestroy(test_pcpu_zone);
} else {
printf("run_zone_test: skipping sequester test (not enabled)\n");
}
printf("run_zone_test: Test passed\n");
simple_lock(&zone_test_lock, &zone_locks_grp);
zone_test_running = FALSE;
simple_unlock(&zone_test_lock);
return TRUE;
}
/*
* Routines to test that zone garbage collection and zone replenish threads
* running at the same time don't cause problems.
*/
void
zone_gc_replenish_test(void)
{
zone_gc(ZONE_GC_DRAIN);
}
void
zone_alloc_replenish_test(void)
{
zone_t z = NULL;
struct data { struct data *next; } *node, *list = NULL;
/*
* Find a zone that has a replenish thread
*/
zone_index_foreach(i) {
z = &zone_array[i];
if (z->z_replenishes && zone_elem_size(z) >= sizeof(struct data)) {
z = &zone_array[i];
break;
}
}
if (z == NULL) {
printf("Couldn't find a replenish zone\n");
return;
}
for (uint32_t i = 0; i < 2000; ++i) { /* something big enough to go past replenishment */
node = zalloc(z);
node->next = list;
list = node;
}
/*
* release the memory we allocated
*/
while (list != NULL) {
node = list;
list = list->next;
zfree(z, node);
}
}
#endif /* DEBUG || DEVELOPMENT */