linux/arch/x86/kernel/cpu/perf_event.h
Stephane Eranian 2f7f73a520 perf/x86: Fix shared register mutual exclusion enforcement
This patch fixes a problem with the shared registers mutual
exclusion code and incremental event scheduling by the
generic perf_event code.

There was a bug whereby the mutual exclusion on the shared
registers was not enforced because of incremental scheduling
abort due to event constraints. As an example on Intel
Nehalem, consider the following events:

group1= L1D_CACHE_LD:E_STATE,OFFCORE_RESPONSE_0:PF_RFO,L1D_CACHE_LD:I_STATE
group2= L1D_CACHE_LD:I_STATE

The L1D_CACHE_LD event can only be measured by 2 counters. Yet, there
are 3 instances here. The first group can be scheduled and is committed.
Then, the generic code tries to schedule group2 and this fails (because
there is no more counter to support the 3rd instance of L1D_CACHE_LD).
But in x86_schedule_events() error path, put_event_contraints() is invoked
on ALL the events and not just the ones that just failed. That causes the
"lock" on the shared offcore_response MSR to be released. Yet the first group
is actually scheduled and is exposed to reprogramming of that shared msr by
the sibling HT thread. In other words, there is no guarantee on what is
measured.

This patch fixes the problem by tagging committed events with the
PERF_X86_EVENT_COMMITTED tag. In the error path of x86_schedule_events(),
only the events NOT tagged have their constraint released. The tag
is eventually removed when the event in descheduled.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130620164254.GA3556@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-26 21:58:49 +02:00

718 lines
18 KiB
C

/*
* Performance events x86 architecture header
*
* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
* Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
* Copyright (C) 2009 Jaswinder Singh Rajput
* Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter
* Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
* Copyright (C) 2009 Intel Corporation, <markus.t.metzger@intel.com>
* Copyright (C) 2009 Google, Inc., Stephane Eranian
*
* For licencing details see kernel-base/COPYING
*/
#include <linux/perf_event.h>
#if 0
#undef wrmsrl
#define wrmsrl(msr, val) \
do { \
unsigned int _msr = (msr); \
u64 _val = (val); \
trace_printk("wrmsrl(%x, %Lx)\n", (unsigned int)(_msr), \
(unsigned long long)(_val)); \
native_write_msr((_msr), (u32)(_val), (u32)(_val >> 32)); \
} while (0)
#endif
/*
* | NHM/WSM | SNB |
* register -------------------------------
* | HT | no HT | HT | no HT |
*-----------------------------------------
* offcore | core | core | cpu | core |
* lbr_sel | core | core | cpu | core |
* ld_lat | cpu | core | cpu | core |
*-----------------------------------------
*
* Given that there is a small number of shared regs,
* we can pre-allocate their slot in the per-cpu
* per-core reg tables.
*/
enum extra_reg_type {
EXTRA_REG_NONE = -1, /* not used */
EXTRA_REG_RSP_0 = 0, /* offcore_response_0 */
EXTRA_REG_RSP_1 = 1, /* offcore_response_1 */
EXTRA_REG_LBR = 2, /* lbr_select */
EXTRA_REG_LDLAT = 3, /* ld_lat_threshold */
EXTRA_REG_MAX /* number of entries needed */
};
struct event_constraint {
union {
unsigned long idxmsk[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
u64 idxmsk64;
};
u64 code;
u64 cmask;
int weight;
int overlap;
int flags;
};
/*
* struct hw_perf_event.flags flags
*/
#define PERF_X86_EVENT_PEBS_LDLAT 0x1 /* ld+ldlat data address sampling */
#define PERF_X86_EVENT_PEBS_ST 0x2 /* st data address sampling */
#define PERF_X86_EVENT_PEBS_ST_HSW 0x4 /* haswell style st data sampling */
#define PERF_X86_EVENT_COMMITTED 0x8 /* event passed commit_txn */
struct amd_nb {
int nb_id; /* NorthBridge id */
int refcnt; /* reference count */
struct perf_event *owners[X86_PMC_IDX_MAX];
struct event_constraint event_constraints[X86_PMC_IDX_MAX];
};
/* The maximal number of PEBS events: */
#define MAX_PEBS_EVENTS 8
/*
* A debug store configuration.
*
* We only support architectures that use 64bit fields.
*/
struct debug_store {
u64 bts_buffer_base;
u64 bts_index;
u64 bts_absolute_maximum;
u64 bts_interrupt_threshold;
u64 pebs_buffer_base;
u64 pebs_index;
u64 pebs_absolute_maximum;
u64 pebs_interrupt_threshold;
u64 pebs_event_reset[MAX_PEBS_EVENTS];
};
/*
* Per register state.
*/
struct er_account {
raw_spinlock_t lock; /* per-core: protect structure */
u64 config; /* extra MSR config */
u64 reg; /* extra MSR number */
atomic_t ref; /* reference count */
};
/*
* Per core/cpu state
*
* Used to coordinate shared registers between HT threads or
* among events on a single PMU.
*/
struct intel_shared_regs {
struct er_account regs[EXTRA_REG_MAX];
int refcnt; /* per-core: #HT threads */
unsigned core_id; /* per-core: core id */
};
#define MAX_LBR_ENTRIES 16
struct cpu_hw_events {
/*
* Generic x86 PMC bits
*/
struct perf_event *events[X86_PMC_IDX_MAX]; /* in counter order */
unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
unsigned long running[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
int enabled;
int n_events;
int n_added;
int n_txn;
int assign[X86_PMC_IDX_MAX]; /* event to counter assignment */
u64 tags[X86_PMC_IDX_MAX];
struct perf_event *event_list[X86_PMC_IDX_MAX]; /* in enabled order */
unsigned int group_flag;
int is_fake;
/*
* Intel DebugStore bits
*/
struct debug_store *ds;
u64 pebs_enabled;
/*
* Intel LBR bits
*/
int lbr_users;
void *lbr_context;
struct perf_branch_stack lbr_stack;
struct perf_branch_entry lbr_entries[MAX_LBR_ENTRIES];
struct er_account *lbr_sel;
u64 br_sel;
/*
* Intel host/guest exclude bits
*/
u64 intel_ctrl_guest_mask;
u64 intel_ctrl_host_mask;
struct perf_guest_switch_msr guest_switch_msrs[X86_PMC_IDX_MAX];
/*
* manage shared (per-core, per-cpu) registers
* used on Intel NHM/WSM/SNB
*/
struct intel_shared_regs *shared_regs;
/*
* AMD specific bits
*/
struct amd_nb *amd_nb;
/* Inverted mask of bits to clear in the perf_ctr ctrl registers */
u64 perf_ctr_virt_mask;
void *kfree_on_online;
};
#define __EVENT_CONSTRAINT(c, n, m, w, o, f) {\
{ .idxmsk64 = (n) }, \
.code = (c), \
.cmask = (m), \
.weight = (w), \
.overlap = (o), \
.flags = f, \
}
#define EVENT_CONSTRAINT(c, n, m) \
__EVENT_CONSTRAINT(c, n, m, HWEIGHT(n), 0, 0)
/*
* The overlap flag marks event constraints with overlapping counter
* masks. This is the case if the counter mask of such an event is not
* a subset of any other counter mask of a constraint with an equal or
* higher weight, e.g.:
*
* c_overlaps = EVENT_CONSTRAINT_OVERLAP(0, 0x09, 0);
* c_another1 = EVENT_CONSTRAINT(0, 0x07, 0);
* c_another2 = EVENT_CONSTRAINT(0, 0x38, 0);
*
* The event scheduler may not select the correct counter in the first
* cycle because it needs to know which subsequent events will be
* scheduled. It may fail to schedule the events then. So we set the
* overlap flag for such constraints to give the scheduler a hint which
* events to select for counter rescheduling.
*
* Care must be taken as the rescheduling algorithm is O(n!) which
* will increase scheduling cycles for an over-commited system
* dramatically. The number of such EVENT_CONSTRAINT_OVERLAP() macros
* and its counter masks must be kept at a minimum.
*/
#define EVENT_CONSTRAINT_OVERLAP(c, n, m) \
__EVENT_CONSTRAINT(c, n, m, HWEIGHT(n), 1, 0)
/*
* Constraint on the Event code.
*/
#define INTEL_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, n, ARCH_PERFMON_EVENTSEL_EVENT)
/*
* Constraint on the Event code + UMask + fixed-mask
*
* filter mask to validate fixed counter events.
* the following filters disqualify for fixed counters:
* - inv
* - edge
* - cnt-mask
* - in_tx
* - in_tx_checkpointed
* The other filters are supported by fixed counters.
* The any-thread option is supported starting with v3.
*/
#define FIXED_EVENT_FLAGS (X86_RAW_EVENT_MASK|HSW_IN_TX|HSW_IN_TX_CHECKPOINTED)
#define FIXED_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, (1ULL << (32+n)), FIXED_EVENT_FLAGS)
/*
* Constraint on the Event code + UMask
*/
#define INTEL_UEVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVENT_MASK)
#define INTEL_PLD_CONSTRAINT(c, n) \
__EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVENT_MASK, \
HWEIGHT(n), 0, PERF_X86_EVENT_PEBS_LDLAT)
#define INTEL_PST_CONSTRAINT(c, n) \
__EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVENT_MASK, \
HWEIGHT(n), 0, PERF_X86_EVENT_PEBS_ST)
/* DataLA version of store sampling without extra enable bit. */
#define INTEL_PST_HSW_CONSTRAINT(c, n) \
__EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVENT_MASK, \
HWEIGHT(n), 0, PERF_X86_EVENT_PEBS_ST_HSW)
#define EVENT_CONSTRAINT_END \
EVENT_CONSTRAINT(0, 0, 0)
#define for_each_event_constraint(e, c) \
for ((e) = (c); (e)->weight; (e)++)
/*
* Extra registers for specific events.
*
* Some events need large masks and require external MSRs.
* Those extra MSRs end up being shared for all events on
* a PMU and sometimes between PMU of sibling HT threads.
* In either case, the kernel needs to handle conflicting
* accesses to those extra, shared, regs. The data structure
* to manage those registers is stored in cpu_hw_event.
*/
struct extra_reg {
unsigned int event;
unsigned int msr;
u64 config_mask;
u64 valid_mask;
int idx; /* per_xxx->regs[] reg index */
};
#define EVENT_EXTRA_REG(e, ms, m, vm, i) { \
.event = (e), \
.msr = (ms), \
.config_mask = (m), \
.valid_mask = (vm), \
.idx = EXTRA_REG_##i, \
}
#define INTEL_EVENT_EXTRA_REG(event, msr, vm, idx) \
EVENT_EXTRA_REG(event, msr, ARCH_PERFMON_EVENTSEL_EVENT, vm, idx)
#define INTEL_UEVENT_EXTRA_REG(event, msr, vm, idx) \
EVENT_EXTRA_REG(event, msr, ARCH_PERFMON_EVENTSEL_EVENT | \
ARCH_PERFMON_EVENTSEL_UMASK, vm, idx)
#define INTEL_UEVENT_PEBS_LDLAT_EXTRA_REG(c) \
INTEL_UEVENT_EXTRA_REG(c, \
MSR_PEBS_LD_LAT_THRESHOLD, \
0xffff, \
LDLAT)
#define EVENT_EXTRA_END EVENT_EXTRA_REG(0, 0, 0, 0, RSP_0)
union perf_capabilities {
struct {
u64 lbr_format:6;
u64 pebs_trap:1;
u64 pebs_arch_reg:1;
u64 pebs_format:4;
u64 smm_freeze:1;
/*
* PMU supports separate counter range for writing
* values > 32bit.
*/
u64 full_width_write:1;
};
u64 capabilities;
};
struct x86_pmu_quirk {
struct x86_pmu_quirk *next;
void (*func)(void);
};
union x86_pmu_config {
struct {
u64 event:8,
umask:8,
usr:1,
os:1,
edge:1,
pc:1,
interrupt:1,
__reserved1:1,
en:1,
inv:1,
cmask:8,
event2:4,
__reserved2:4,
go:1,
ho:1;
} bits;
u64 value;
};
#define X86_CONFIG(args...) ((union x86_pmu_config){.bits = {args}}).value
/*
* struct x86_pmu - generic x86 pmu
*/
struct x86_pmu {
/*
* Generic x86 PMC bits
*/
const char *name;
int version;
int (*handle_irq)(struct pt_regs *);
void (*disable_all)(void);
void (*enable_all)(int added);
void (*enable)(struct perf_event *);
void (*disable)(struct perf_event *);
int (*hw_config)(struct perf_event *event);
int (*schedule_events)(struct cpu_hw_events *cpuc, int n, int *assign);
unsigned eventsel;
unsigned perfctr;
int (*addr_offset)(int index, bool eventsel);
int (*rdpmc_index)(int index);
u64 (*event_map)(int);
int max_events;
int num_counters;
int num_counters_fixed;
int cntval_bits;
u64 cntval_mask;
union {
unsigned long events_maskl;
unsigned long events_mask[BITS_TO_LONGS(ARCH_PERFMON_EVENTS_COUNT)];
};
int events_mask_len;
int apic;
u64 max_period;
struct event_constraint *
(*get_event_constraints)(struct cpu_hw_events *cpuc,
struct perf_event *event);
void (*put_event_constraints)(struct cpu_hw_events *cpuc,
struct perf_event *event);
struct event_constraint *event_constraints;
struct x86_pmu_quirk *quirks;
int perfctr_second_write;
bool late_ack;
/*
* sysfs attrs
*/
int attr_rdpmc;
struct attribute **format_attrs;
struct attribute **event_attrs;
ssize_t (*events_sysfs_show)(char *page, u64 config);
struct attribute **cpu_events;
/*
* CPU Hotplug hooks
*/
int (*cpu_prepare)(int cpu);
void (*cpu_starting)(int cpu);
void (*cpu_dying)(int cpu);
void (*cpu_dead)(int cpu);
void (*check_microcode)(void);
void (*flush_branch_stack)(void);
/*
* Intel Arch Perfmon v2+
*/
u64 intel_ctrl;
union perf_capabilities intel_cap;
/*
* Intel DebugStore bits
*/
unsigned int bts :1,
bts_active :1,
pebs :1,
pebs_active :1,
pebs_broken :1;
int pebs_record_size;
void (*drain_pebs)(struct pt_regs *regs);
struct event_constraint *pebs_constraints;
void (*pebs_aliases)(struct perf_event *event);
int max_pebs_events;
/*
* Intel LBR
*/
unsigned long lbr_tos, lbr_from, lbr_to; /* MSR base regs */
int lbr_nr; /* hardware stack size */
u64 lbr_sel_mask; /* LBR_SELECT valid bits */
const int *lbr_sel_map; /* lbr_select mappings */
/*
* Extra registers for events
*/
struct extra_reg *extra_regs;
unsigned int er_flags;
/*
* Intel host/guest support (KVM)
*/
struct perf_guest_switch_msr *(*guest_get_msrs)(int *nr);
};
#define x86_add_quirk(func_) \
do { \
static struct x86_pmu_quirk __quirk __initdata = { \
.func = func_, \
}; \
__quirk.next = x86_pmu.quirks; \
x86_pmu.quirks = &__quirk; \
} while (0)
#define ERF_NO_HT_SHARING 1
#define ERF_HAS_RSP_1 2
#define EVENT_VAR(_id) event_attr_##_id
#define EVENT_PTR(_id) &event_attr_##_id.attr.attr
#define EVENT_ATTR(_name, _id) \
static struct perf_pmu_events_attr EVENT_VAR(_id) = { \
.attr = __ATTR(_name, 0444, events_sysfs_show, NULL), \
.id = PERF_COUNT_HW_##_id, \
.event_str = NULL, \
};
#define EVENT_ATTR_STR(_name, v, str) \
static struct perf_pmu_events_attr event_attr_##v = { \
.attr = __ATTR(_name, 0444, events_sysfs_show, NULL), \
.id = 0, \
.event_str = str, \
};
extern struct x86_pmu x86_pmu __read_mostly;
DECLARE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
int x86_perf_event_set_period(struct perf_event *event);
/*
* Generalized hw caching related hw_event table, filled
* in on a per model basis. A value of 0 means
* 'not supported', -1 means 'hw_event makes no sense on
* this CPU', any other value means the raw hw_event
* ID.
*/
#define C(x) PERF_COUNT_HW_CACHE_##x
extern u64 __read_mostly hw_cache_event_ids
[PERF_COUNT_HW_CACHE_MAX]
[PERF_COUNT_HW_CACHE_OP_MAX]
[PERF_COUNT_HW_CACHE_RESULT_MAX];
extern u64 __read_mostly hw_cache_extra_regs
[PERF_COUNT_HW_CACHE_MAX]
[PERF_COUNT_HW_CACHE_OP_MAX]
[PERF_COUNT_HW_CACHE_RESULT_MAX];
u64 x86_perf_event_update(struct perf_event *event);
static inline unsigned int x86_pmu_config_addr(int index)
{
return x86_pmu.eventsel + (x86_pmu.addr_offset ?
x86_pmu.addr_offset(index, true) : index);
}
static inline unsigned int x86_pmu_event_addr(int index)
{
return x86_pmu.perfctr + (x86_pmu.addr_offset ?
x86_pmu.addr_offset(index, false) : index);
}
static inline int x86_pmu_rdpmc_index(int index)
{
return x86_pmu.rdpmc_index ? x86_pmu.rdpmc_index(index) : index;
}
int x86_setup_perfctr(struct perf_event *event);
int x86_pmu_hw_config(struct perf_event *event);
void x86_pmu_disable_all(void);
static inline void __x86_pmu_enable_event(struct hw_perf_event *hwc,
u64 enable_mask)
{
u64 disable_mask = __this_cpu_read(cpu_hw_events.perf_ctr_virt_mask);
if (hwc->extra_reg.reg)
wrmsrl(hwc->extra_reg.reg, hwc->extra_reg.config);
wrmsrl(hwc->config_base, (hwc->config | enable_mask) & ~disable_mask);
}
void x86_pmu_enable_all(int added);
int perf_assign_events(struct perf_event **events, int n,
int wmin, int wmax, int *assign);
int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign);
void x86_pmu_stop(struct perf_event *event, int flags);
static inline void x86_pmu_disable_event(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
wrmsrl(hwc->config_base, hwc->config);
}
void x86_pmu_enable_event(struct perf_event *event);
int x86_pmu_handle_irq(struct pt_regs *regs);
extern struct event_constraint emptyconstraint;
extern struct event_constraint unconstrained;
static inline bool kernel_ip(unsigned long ip)
{
#ifdef CONFIG_X86_32
return ip > PAGE_OFFSET;
#else
return (long)ip < 0;
#endif
}
/*
* Not all PMUs provide the right context information to place the reported IP
* into full context. Specifically segment registers are typically not
* supplied.
*
* Assuming the address is a linear address (it is for IBS), we fake the CS and
* vm86 mode using the known zero-based code segment and 'fix up' the registers
* to reflect this.
*
* Intel PEBS/LBR appear to typically provide the effective address, nothing
* much we can do about that but pray and treat it like a linear address.
*/
static inline void set_linear_ip(struct pt_regs *regs, unsigned long ip)
{
regs->cs = kernel_ip(ip) ? __KERNEL_CS : __USER_CS;
if (regs->flags & X86_VM_MASK)
regs->flags ^= (PERF_EFLAGS_VM | X86_VM_MASK);
regs->ip = ip;
}
ssize_t x86_event_sysfs_show(char *page, u64 config, u64 event);
ssize_t intel_event_sysfs_show(char *page, u64 config);
#ifdef CONFIG_CPU_SUP_AMD
int amd_pmu_init(void);
#else /* CONFIG_CPU_SUP_AMD */
static inline int amd_pmu_init(void)
{
return 0;
}
#endif /* CONFIG_CPU_SUP_AMD */
#ifdef CONFIG_CPU_SUP_INTEL
int intel_pmu_save_and_restart(struct perf_event *event);
struct event_constraint *
x86_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event);
struct intel_shared_regs *allocate_shared_regs(int cpu);
int intel_pmu_init(void);
void init_debug_store_on_cpu(int cpu);
void fini_debug_store_on_cpu(int cpu);
void release_ds_buffers(void);
void reserve_ds_buffers(void);
extern struct event_constraint bts_constraint;
void intel_pmu_enable_bts(u64 config);
void intel_pmu_disable_bts(void);
int intel_pmu_drain_bts_buffer(void);
extern struct event_constraint intel_core2_pebs_event_constraints[];
extern struct event_constraint intel_atom_pebs_event_constraints[];
extern struct event_constraint intel_nehalem_pebs_event_constraints[];
extern struct event_constraint intel_westmere_pebs_event_constraints[];
extern struct event_constraint intel_snb_pebs_event_constraints[];
extern struct event_constraint intel_ivb_pebs_event_constraints[];
extern struct event_constraint intel_hsw_pebs_event_constraints[];
struct event_constraint *intel_pebs_constraints(struct perf_event *event);
void intel_pmu_pebs_enable(struct perf_event *event);
void intel_pmu_pebs_disable(struct perf_event *event);
void intel_pmu_pebs_enable_all(void);
void intel_pmu_pebs_disable_all(void);
void intel_ds_init(void);
void intel_pmu_lbr_reset(void);
void intel_pmu_lbr_enable(struct perf_event *event);
void intel_pmu_lbr_disable(struct perf_event *event);
void intel_pmu_lbr_enable_all(void);
void intel_pmu_lbr_disable_all(void);
void intel_pmu_lbr_read(void);
void intel_pmu_lbr_init_core(void);
void intel_pmu_lbr_init_nhm(void);
void intel_pmu_lbr_init_atom(void);
void intel_pmu_lbr_init_snb(void);
int intel_pmu_setup_lbr_filter(struct perf_event *event);
int p4_pmu_init(void);
int p6_pmu_init(void);
int knc_pmu_init(void);
ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr,
char *page);
#else /* CONFIG_CPU_SUP_INTEL */
static inline void reserve_ds_buffers(void)
{
}
static inline void release_ds_buffers(void)
{
}
static inline int intel_pmu_init(void)
{
return 0;
}
static inline struct intel_shared_regs *allocate_shared_regs(int cpu)
{
return NULL;
}
#endif /* CONFIG_CPU_SUP_INTEL */