linux/kernel/kexec_core.c
Minfei Huang 04e9949b2d kexec: remove unnecessary test in kimage_alloc_crash_control_pages()
Transforming PFN(Page Frame Number) to struct page is never failure, so we
can simplify the code logic to do the image->control_page assignment
directly in the loop, and remove the unnecessary conditional judgement.

Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 13:29:01 -07:00

1511 lines
37 KiB
C

/*
* kexec.c - kexec system call core code.
* Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#define pr_fmt(fmt) "kexec: " fmt
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/kexec.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/highmem.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/ioport.h>
#include <linux/hardirq.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/utsname.h>
#include <linux/numa.h>
#include <linux/suspend.h>
#include <linux/device.h>
#include <linux/freezer.h>
#include <linux/pm.h>
#include <linux/cpu.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/console.h>
#include <linux/vmalloc.h>
#include <linux/swap.h>
#include <linux/syscore_ops.h>
#include <linux/compiler.h>
#include <linux/hugetlb.h>
#include <asm/page.h>
#include <asm/sections.h>
#include <crypto/hash.h>
#include <crypto/sha.h>
#include "kexec_internal.h"
DEFINE_MUTEX(kexec_mutex);
/* Per cpu memory for storing cpu states in case of system crash. */
note_buf_t __percpu *crash_notes;
/* vmcoreinfo stuff */
static unsigned char vmcoreinfo_data[VMCOREINFO_BYTES];
u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
size_t vmcoreinfo_size;
size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
/* Flag to indicate we are going to kexec a new kernel */
bool kexec_in_progress = false;
/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
struct resource crashk_low_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
int kexec_should_crash(struct task_struct *p)
{
/*
* If crash_kexec_post_notifiers is enabled, don't run
* crash_kexec() here yet, which must be run after panic
* notifiers in panic().
*/
if (crash_kexec_post_notifiers)
return 0;
/*
* There are 4 panic() calls in do_exit() path, each of which
* corresponds to each of these 4 conditions.
*/
if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
return 1;
return 0;
}
/*
* When kexec transitions to the new kernel there is a one-to-one
* mapping between physical and virtual addresses. On processors
* where you can disable the MMU this is trivial, and easy. For
* others it is still a simple predictable page table to setup.
*
* In that environment kexec copies the new kernel to its final
* resting place. This means I can only support memory whose
* physical address can fit in an unsigned long. In particular
* addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
* If the assembly stub has more restrictive requirements
* KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
* defined more restrictively in <asm/kexec.h>.
*
* The code for the transition from the current kernel to the
* the new kernel is placed in the control_code_buffer, whose size
* is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single
* page of memory is necessary, but some architectures require more.
* Because this memory must be identity mapped in the transition from
* virtual to physical addresses it must live in the range
* 0 - TASK_SIZE, as only the user space mappings are arbitrarily
* modifiable.
*
* The assembly stub in the control code buffer is passed a linked list
* of descriptor pages detailing the source pages of the new kernel,
* and the destination addresses of those source pages. As this data
* structure is not used in the context of the current OS, it must
* be self-contained.
*
* The code has been made to work with highmem pages and will use a
* destination page in its final resting place (if it happens
* to allocate it). The end product of this is that most of the
* physical address space, and most of RAM can be used.
*
* Future directions include:
* - allocating a page table with the control code buffer identity
* mapped, to simplify machine_kexec and make kexec_on_panic more
* reliable.
*/
/*
* KIMAGE_NO_DEST is an impossible destination address..., for
* allocating pages whose destination address we do not care about.
*/
#define KIMAGE_NO_DEST (-1UL)
static struct page *kimage_alloc_page(struct kimage *image,
gfp_t gfp_mask,
unsigned long dest);
int sanity_check_segment_list(struct kimage *image)
{
int result, i;
unsigned long nr_segments = image->nr_segments;
/*
* Verify we have good destination addresses. The caller is
* responsible for making certain we don't attempt to load
* the new image into invalid or reserved areas of RAM. This
* just verifies it is an address we can use.
*
* Since the kernel does everything in page size chunks ensure
* the destination addresses are page aligned. Too many
* special cases crop of when we don't do this. The most
* insidious is getting overlapping destination addresses
* simply because addresses are changed to page size
* granularity.
*/
result = -EADDRNOTAVAIL;
for (i = 0; i < nr_segments; i++) {
unsigned long mstart, mend;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz;
if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
return result;
if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
return result;
}
/* Verify our destination addresses do not overlap.
* If we alloed overlapping destination addresses
* through very weird things can happen with no
* easy explanation as one segment stops on another.
*/
result = -EINVAL;
for (i = 0; i < nr_segments; i++) {
unsigned long mstart, mend;
unsigned long j;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz;
for (j = 0; j < i; j++) {
unsigned long pstart, pend;
pstart = image->segment[j].mem;
pend = pstart + image->segment[j].memsz;
/* Do the segments overlap ? */
if ((mend > pstart) && (mstart < pend))
return result;
}
}
/* Ensure our buffer sizes are strictly less than
* our memory sizes. This should always be the case,
* and it is easier to check up front than to be surprised
* later on.
*/
result = -EINVAL;
for (i = 0; i < nr_segments; i++) {
if (image->segment[i].bufsz > image->segment[i].memsz)
return result;
}
/*
* Verify we have good destination addresses. Normally
* the caller is responsible for making certain we don't
* attempt to load the new image into invalid or reserved
* areas of RAM. But crash kernels are preloaded into a
* reserved area of ram. We must ensure the addresses
* are in the reserved area otherwise preloading the
* kernel could corrupt things.
*/
if (image->type == KEXEC_TYPE_CRASH) {
result = -EADDRNOTAVAIL;
for (i = 0; i < nr_segments; i++) {
unsigned long mstart, mend;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz - 1;
/* Ensure we are within the crash kernel limits */
if ((mstart < crashk_res.start) ||
(mend > crashk_res.end))
return result;
}
}
return 0;
}
struct kimage *do_kimage_alloc_init(void)
{
struct kimage *image;
/* Allocate a controlling structure */
image = kzalloc(sizeof(*image), GFP_KERNEL);
if (!image)
return NULL;
image->head = 0;
image->entry = &image->head;
image->last_entry = &image->head;
image->control_page = ~0; /* By default this does not apply */
image->type = KEXEC_TYPE_DEFAULT;
/* Initialize the list of control pages */
INIT_LIST_HEAD(&image->control_pages);
/* Initialize the list of destination pages */
INIT_LIST_HEAD(&image->dest_pages);
/* Initialize the list of unusable pages */
INIT_LIST_HEAD(&image->unusable_pages);
return image;
}
int kimage_is_destination_range(struct kimage *image,
unsigned long start,
unsigned long end)
{
unsigned long i;
for (i = 0; i < image->nr_segments; i++) {
unsigned long mstart, mend;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz;
if ((end > mstart) && (start < mend))
return 1;
}
return 0;
}
static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
{
struct page *pages;
pages = alloc_pages(gfp_mask, order);
if (pages) {
unsigned int count, i;
pages->mapping = NULL;
set_page_private(pages, order);
count = 1 << order;
for (i = 0; i < count; i++)
SetPageReserved(pages + i);
}
return pages;
}
static void kimage_free_pages(struct page *page)
{
unsigned int order, count, i;
order = page_private(page);
count = 1 << order;
for (i = 0; i < count; i++)
ClearPageReserved(page + i);
__free_pages(page, order);
}
void kimage_free_page_list(struct list_head *list)
{
struct list_head *pos, *next;
list_for_each_safe(pos, next, list) {
struct page *page;
page = list_entry(pos, struct page, lru);
list_del(&page->lru);
kimage_free_pages(page);
}
}
static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
unsigned int order)
{
/* Control pages are special, they are the intermediaries
* that are needed while we copy the rest of the pages
* to their final resting place. As such they must
* not conflict with either the destination addresses
* or memory the kernel is already using.
*
* The only case where we really need more than one of
* these are for architectures where we cannot disable
* the MMU and must instead generate an identity mapped
* page table for all of the memory.
*
* At worst this runs in O(N) of the image size.
*/
struct list_head extra_pages;
struct page *pages;
unsigned int count;
count = 1 << order;
INIT_LIST_HEAD(&extra_pages);
/* Loop while I can allocate a page and the page allocated
* is a destination page.
*/
do {
unsigned long pfn, epfn, addr, eaddr;
pages = kimage_alloc_pages(KEXEC_CONTROL_MEMORY_GFP, order);
if (!pages)
break;
pfn = page_to_pfn(pages);
epfn = pfn + count;
addr = pfn << PAGE_SHIFT;
eaddr = epfn << PAGE_SHIFT;
if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
kimage_is_destination_range(image, addr, eaddr)) {
list_add(&pages->lru, &extra_pages);
pages = NULL;
}
} while (!pages);
if (pages) {
/* Remember the allocated page... */
list_add(&pages->lru, &image->control_pages);
/* Because the page is already in it's destination
* location we will never allocate another page at
* that address. Therefore kimage_alloc_pages
* will not return it (again) and we don't need
* to give it an entry in image->segment[].
*/
}
/* Deal with the destination pages I have inadvertently allocated.
*
* Ideally I would convert multi-page allocations into single
* page allocations, and add everything to image->dest_pages.
*
* For now it is simpler to just free the pages.
*/
kimage_free_page_list(&extra_pages);
return pages;
}
static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
unsigned int order)
{
/* Control pages are special, they are the intermediaries
* that are needed while we copy the rest of the pages
* to their final resting place. As such they must
* not conflict with either the destination addresses
* or memory the kernel is already using.
*
* Control pages are also the only pags we must allocate
* when loading a crash kernel. All of the other pages
* are specified by the segments and we just memcpy
* into them directly.
*
* The only case where we really need more than one of
* these are for architectures where we cannot disable
* the MMU and must instead generate an identity mapped
* page table for all of the memory.
*
* Given the low demand this implements a very simple
* allocator that finds the first hole of the appropriate
* size in the reserved memory region, and allocates all
* of the memory up to and including the hole.
*/
unsigned long hole_start, hole_end, size;
struct page *pages;
pages = NULL;
size = (1 << order) << PAGE_SHIFT;
hole_start = (image->control_page + (size - 1)) & ~(size - 1);
hole_end = hole_start + size - 1;
while (hole_end <= crashk_res.end) {
unsigned long i;
if (hole_end > KEXEC_CRASH_CONTROL_MEMORY_LIMIT)
break;
/* See if I overlap any of the segments */
for (i = 0; i < image->nr_segments; i++) {
unsigned long mstart, mend;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz - 1;
if ((hole_end >= mstart) && (hole_start <= mend)) {
/* Advance the hole to the end of the segment */
hole_start = (mend + (size - 1)) & ~(size - 1);
hole_end = hole_start + size - 1;
break;
}
}
/* If I don't overlap any segments I have found my hole! */
if (i == image->nr_segments) {
pages = pfn_to_page(hole_start >> PAGE_SHIFT);
image->control_page = hole_end;
break;
}
}
return pages;
}
struct page *kimage_alloc_control_pages(struct kimage *image,
unsigned int order)
{
struct page *pages = NULL;
switch (image->type) {
case KEXEC_TYPE_DEFAULT:
pages = kimage_alloc_normal_control_pages(image, order);
break;
case KEXEC_TYPE_CRASH:
pages = kimage_alloc_crash_control_pages(image, order);
break;
}
return pages;
}
static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
{
if (*image->entry != 0)
image->entry++;
if (image->entry == image->last_entry) {
kimage_entry_t *ind_page;
struct page *page;
page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
if (!page)
return -ENOMEM;
ind_page = page_address(page);
*image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
image->entry = ind_page;
image->last_entry = ind_page +
((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
}
*image->entry = entry;
image->entry++;
*image->entry = 0;
return 0;
}
static int kimage_set_destination(struct kimage *image,
unsigned long destination)
{
int result;
destination &= PAGE_MASK;
result = kimage_add_entry(image, destination | IND_DESTINATION);
return result;
}
static int kimage_add_page(struct kimage *image, unsigned long page)
{
int result;
page &= PAGE_MASK;
result = kimage_add_entry(image, page | IND_SOURCE);
return result;
}
static void kimage_free_extra_pages(struct kimage *image)
{
/* Walk through and free any extra destination pages I may have */
kimage_free_page_list(&image->dest_pages);
/* Walk through and free any unusable pages I have cached */
kimage_free_page_list(&image->unusable_pages);
}
void kimage_terminate(struct kimage *image)
{
if (*image->entry != 0)
image->entry++;
*image->entry = IND_DONE;
}
#define for_each_kimage_entry(image, ptr, entry) \
for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
ptr = (entry & IND_INDIRECTION) ? \
phys_to_virt((entry & PAGE_MASK)) : ptr + 1)
static void kimage_free_entry(kimage_entry_t entry)
{
struct page *page;
page = pfn_to_page(entry >> PAGE_SHIFT);
kimage_free_pages(page);
}
void kimage_free(struct kimage *image)
{
kimage_entry_t *ptr, entry;
kimage_entry_t ind = 0;
if (!image)
return;
kimage_free_extra_pages(image);
for_each_kimage_entry(image, ptr, entry) {
if (entry & IND_INDIRECTION) {
/* Free the previous indirection page */
if (ind & IND_INDIRECTION)
kimage_free_entry(ind);
/* Save this indirection page until we are
* done with it.
*/
ind = entry;
} else if (entry & IND_SOURCE)
kimage_free_entry(entry);
}
/* Free the final indirection page */
if (ind & IND_INDIRECTION)
kimage_free_entry(ind);
/* Handle any machine specific cleanup */
machine_kexec_cleanup(image);
/* Free the kexec control pages... */
kimage_free_page_list(&image->control_pages);
/*
* Free up any temporary buffers allocated. This might hit if
* error occurred much later after buffer allocation.
*/
if (image->file_mode)
kimage_file_post_load_cleanup(image);
kfree(image);
}
static kimage_entry_t *kimage_dst_used(struct kimage *image,
unsigned long page)
{
kimage_entry_t *ptr, entry;
unsigned long destination = 0;
for_each_kimage_entry(image, ptr, entry) {
if (entry & IND_DESTINATION)
destination = entry & PAGE_MASK;
else if (entry & IND_SOURCE) {
if (page == destination)
return ptr;
destination += PAGE_SIZE;
}
}
return NULL;
}
static struct page *kimage_alloc_page(struct kimage *image,
gfp_t gfp_mask,
unsigned long destination)
{
/*
* Here we implement safeguards to ensure that a source page
* is not copied to its destination page before the data on
* the destination page is no longer useful.
*
* To do this we maintain the invariant that a source page is
* either its own destination page, or it is not a
* destination page at all.
*
* That is slightly stronger than required, but the proof
* that no problems will not occur is trivial, and the
* implementation is simply to verify.
*
* When allocating all pages normally this algorithm will run
* in O(N) time, but in the worst case it will run in O(N^2)
* time. If the runtime is a problem the data structures can
* be fixed.
*/
struct page *page;
unsigned long addr;
/*
* Walk through the list of destination pages, and see if I
* have a match.
*/
list_for_each_entry(page, &image->dest_pages, lru) {
addr = page_to_pfn(page) << PAGE_SHIFT;
if (addr == destination) {
list_del(&page->lru);
return page;
}
}
page = NULL;
while (1) {
kimage_entry_t *old;
/* Allocate a page, if we run out of memory give up */
page = kimage_alloc_pages(gfp_mask, 0);
if (!page)
return NULL;
/* If the page cannot be used file it away */
if (page_to_pfn(page) >
(KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
list_add(&page->lru, &image->unusable_pages);
continue;
}
addr = page_to_pfn(page) << PAGE_SHIFT;
/* If it is the destination page we want use it */
if (addr == destination)
break;
/* If the page is not a destination page use it */
if (!kimage_is_destination_range(image, addr,
addr + PAGE_SIZE))
break;
/*
* I know that the page is someones destination page.
* See if there is already a source page for this
* destination page. And if so swap the source pages.
*/
old = kimage_dst_used(image, addr);
if (old) {
/* If so move it */
unsigned long old_addr;
struct page *old_page;
old_addr = *old & PAGE_MASK;
old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
copy_highpage(page, old_page);
*old = addr | (*old & ~PAGE_MASK);
/* The old page I have found cannot be a
* destination page, so return it if it's
* gfp_flags honor the ones passed in.
*/
if (!(gfp_mask & __GFP_HIGHMEM) &&
PageHighMem(old_page)) {
kimage_free_pages(old_page);
continue;
}
addr = old_addr;
page = old_page;
break;
}
/* Place the page on the destination list, to be used later */
list_add(&page->lru, &image->dest_pages);
}
return page;
}
static int kimage_load_normal_segment(struct kimage *image,
struct kexec_segment *segment)
{
unsigned long maddr;
size_t ubytes, mbytes;
int result;
unsigned char __user *buf = NULL;
unsigned char *kbuf = NULL;
result = 0;
if (image->file_mode)
kbuf = segment->kbuf;
else
buf = segment->buf;
ubytes = segment->bufsz;
mbytes = segment->memsz;
maddr = segment->mem;
result = kimage_set_destination(image, maddr);
if (result < 0)
goto out;
while (mbytes) {
struct page *page;
char *ptr;
size_t uchunk, mchunk;
page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
if (!page) {
result = -ENOMEM;
goto out;
}
result = kimage_add_page(image, page_to_pfn(page)
<< PAGE_SHIFT);
if (result < 0)
goto out;
ptr = kmap(page);
/* Start with a clear page */
clear_page(ptr);
ptr += maddr & ~PAGE_MASK;
mchunk = min_t(size_t, mbytes,
PAGE_SIZE - (maddr & ~PAGE_MASK));
uchunk = min(ubytes, mchunk);
/* For file based kexec, source pages are in kernel memory */
if (image->file_mode)
memcpy(ptr, kbuf, uchunk);
else
result = copy_from_user(ptr, buf, uchunk);
kunmap(page);
if (result) {
result = -EFAULT;
goto out;
}
ubytes -= uchunk;
maddr += mchunk;
if (image->file_mode)
kbuf += mchunk;
else
buf += mchunk;
mbytes -= mchunk;
}
out:
return result;
}
static int kimage_load_crash_segment(struct kimage *image,
struct kexec_segment *segment)
{
/* For crash dumps kernels we simply copy the data from
* user space to it's destination.
* We do things a page at a time for the sake of kmap.
*/
unsigned long maddr;
size_t ubytes, mbytes;
int result;
unsigned char __user *buf = NULL;
unsigned char *kbuf = NULL;
result = 0;
if (image->file_mode)
kbuf = segment->kbuf;
else
buf = segment->buf;
ubytes = segment->bufsz;
mbytes = segment->memsz;
maddr = segment->mem;
while (mbytes) {
struct page *page;
char *ptr;
size_t uchunk, mchunk;
page = pfn_to_page(maddr >> PAGE_SHIFT);
if (!page) {
result = -ENOMEM;
goto out;
}
ptr = kmap(page);
ptr += maddr & ~PAGE_MASK;
mchunk = min_t(size_t, mbytes,
PAGE_SIZE - (maddr & ~PAGE_MASK));
uchunk = min(ubytes, mchunk);
if (mchunk > uchunk) {
/* Zero the trailing part of the page */
memset(ptr + uchunk, 0, mchunk - uchunk);
}
/* For file based kexec, source pages are in kernel memory */
if (image->file_mode)
memcpy(ptr, kbuf, uchunk);
else
result = copy_from_user(ptr, buf, uchunk);
kexec_flush_icache_page(page);
kunmap(page);
if (result) {
result = -EFAULT;
goto out;
}
ubytes -= uchunk;
maddr += mchunk;
if (image->file_mode)
kbuf += mchunk;
else
buf += mchunk;
mbytes -= mchunk;
}
out:
return result;
}
int kimage_load_segment(struct kimage *image,
struct kexec_segment *segment)
{
int result = -ENOMEM;
switch (image->type) {
case KEXEC_TYPE_DEFAULT:
result = kimage_load_normal_segment(image, segment);
break;
case KEXEC_TYPE_CRASH:
result = kimage_load_crash_segment(image, segment);
break;
}
return result;
}
struct kimage *kexec_image;
struct kimage *kexec_crash_image;
int kexec_load_disabled;
void crash_kexec(struct pt_regs *regs)
{
/* Take the kexec_mutex here to prevent sys_kexec_load
* running on one cpu from replacing the crash kernel
* we are using after a panic on a different cpu.
*
* If the crash kernel was not located in a fixed area
* of memory the xchg(&kexec_crash_image) would be
* sufficient. But since I reuse the memory...
*/
if (mutex_trylock(&kexec_mutex)) {
if (kexec_crash_image) {
struct pt_regs fixed_regs;
crash_setup_regs(&fixed_regs, regs);
crash_save_vmcoreinfo();
machine_crash_shutdown(&fixed_regs);
machine_kexec(kexec_crash_image);
}
mutex_unlock(&kexec_mutex);
}
}
size_t crash_get_memory_size(void)
{
size_t size = 0;
mutex_lock(&kexec_mutex);
if (crashk_res.end != crashk_res.start)
size = resource_size(&crashk_res);
mutex_unlock(&kexec_mutex);
return size;
}
void __weak crash_free_reserved_phys_range(unsigned long begin,
unsigned long end)
{
unsigned long addr;
for (addr = begin; addr < end; addr += PAGE_SIZE)
free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
}
int crash_shrink_memory(unsigned long new_size)
{
int ret = 0;
unsigned long start, end;
unsigned long old_size;
struct resource *ram_res;
mutex_lock(&kexec_mutex);
if (kexec_crash_image) {
ret = -ENOENT;
goto unlock;
}
start = crashk_res.start;
end = crashk_res.end;
old_size = (end == 0) ? 0 : end - start + 1;
if (new_size >= old_size) {
ret = (new_size == old_size) ? 0 : -EINVAL;
goto unlock;
}
ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
if (!ram_res) {
ret = -ENOMEM;
goto unlock;
}
start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
crash_map_reserved_pages();
crash_free_reserved_phys_range(end, crashk_res.end);
if ((start == end) && (crashk_res.parent != NULL))
release_resource(&crashk_res);
ram_res->start = end;
ram_res->end = crashk_res.end;
ram_res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
ram_res->name = "System RAM";
crashk_res.end = end - 1;
insert_resource(&iomem_resource, ram_res);
crash_unmap_reserved_pages();
unlock:
mutex_unlock(&kexec_mutex);
return ret;
}
static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
size_t data_len)
{
struct elf_note note;
note.n_namesz = strlen(name) + 1;
note.n_descsz = data_len;
note.n_type = type;
memcpy(buf, &note, sizeof(note));
buf += (sizeof(note) + 3)/4;
memcpy(buf, name, note.n_namesz);
buf += (note.n_namesz + 3)/4;
memcpy(buf, data, note.n_descsz);
buf += (note.n_descsz + 3)/4;
return buf;
}
static void final_note(u32 *buf)
{
struct elf_note note;
note.n_namesz = 0;
note.n_descsz = 0;
note.n_type = 0;
memcpy(buf, &note, sizeof(note));
}
void crash_save_cpu(struct pt_regs *regs, int cpu)
{
struct elf_prstatus prstatus;
u32 *buf;
if ((cpu < 0) || (cpu >= nr_cpu_ids))
return;
/* Using ELF notes here is opportunistic.
* I need a well defined structure format
* for the data I pass, and I need tags
* on the data to indicate what information I have
* squirrelled away. ELF notes happen to provide
* all of that, so there is no need to invent something new.
*/
buf = (u32 *)per_cpu_ptr(crash_notes, cpu);
if (!buf)
return;
memset(&prstatus, 0, sizeof(prstatus));
prstatus.pr_pid = current->pid;
elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
&prstatus, sizeof(prstatus));
final_note(buf);
}
static int __init crash_notes_memory_init(void)
{
/* Allocate memory for saving cpu registers. */
crash_notes = alloc_percpu(note_buf_t);
if (!crash_notes) {
pr_warn("Kexec: Memory allocation for saving cpu register states failed\n");
return -ENOMEM;
}
return 0;
}
subsys_initcall(crash_notes_memory_init);
/*
* parsing the "crashkernel" commandline
*
* this code is intended to be called from architecture specific code
*/
/*
* This function parses command lines in the format
*
* crashkernel=ramsize-range:size[,...][@offset]
*
* The function returns 0 on success and -EINVAL on failure.
*/
static int __init parse_crashkernel_mem(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
char *cur = cmdline, *tmp;
/* for each entry of the comma-separated list */
do {
unsigned long long start, end = ULLONG_MAX, size;
/* get the start of the range */
start = memparse(cur, &tmp);
if (cur == tmp) {
pr_warn("crashkernel: Memory value expected\n");
return -EINVAL;
}
cur = tmp;
if (*cur != '-') {
pr_warn("crashkernel: '-' expected\n");
return -EINVAL;
}
cur++;
/* if no ':' is here, than we read the end */
if (*cur != ':') {
end = memparse(cur, &tmp);
if (cur == tmp) {
pr_warn("crashkernel: Memory value expected\n");
return -EINVAL;
}
cur = tmp;
if (end <= start) {
pr_warn("crashkernel: end <= start\n");
return -EINVAL;
}
}
if (*cur != ':') {
pr_warn("crashkernel: ':' expected\n");
return -EINVAL;
}
cur++;
size = memparse(cur, &tmp);
if (cur == tmp) {
pr_warn("Memory value expected\n");
return -EINVAL;
}
cur = tmp;
if (size >= system_ram) {
pr_warn("crashkernel: invalid size\n");
return -EINVAL;
}
/* match ? */
if (system_ram >= start && system_ram < end) {
*crash_size = size;
break;
}
} while (*cur++ == ',');
if (*crash_size > 0) {
while (*cur && *cur != ' ' && *cur != '@')
cur++;
if (*cur == '@') {
cur++;
*crash_base = memparse(cur, &tmp);
if (cur == tmp) {
pr_warn("Memory value expected after '@'\n");
return -EINVAL;
}
}
}
return 0;
}
/*
* That function parses "simple" (old) crashkernel command lines like
*
* crashkernel=size[@offset]
*
* It returns 0 on success and -EINVAL on failure.
*/
static int __init parse_crashkernel_simple(char *cmdline,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
char *cur = cmdline;
*crash_size = memparse(cmdline, &cur);
if (cmdline == cur) {
pr_warn("crashkernel: memory value expected\n");
return -EINVAL;
}
if (*cur == '@')
*crash_base = memparse(cur+1, &cur);
else if (*cur != ' ' && *cur != '\0') {
pr_warn("crashkernel: unrecognized char\n");
return -EINVAL;
}
return 0;
}
#define SUFFIX_HIGH 0
#define SUFFIX_LOW 1
#define SUFFIX_NULL 2
static __initdata char *suffix_tbl[] = {
[SUFFIX_HIGH] = ",high",
[SUFFIX_LOW] = ",low",
[SUFFIX_NULL] = NULL,
};
/*
* That function parses "suffix" crashkernel command lines like
*
* crashkernel=size,[high|low]
*
* It returns 0 on success and -EINVAL on failure.
*/
static int __init parse_crashkernel_suffix(char *cmdline,
unsigned long long *crash_size,
const char *suffix)
{
char *cur = cmdline;
*crash_size = memparse(cmdline, &cur);
if (cmdline == cur) {
pr_warn("crashkernel: memory value expected\n");
return -EINVAL;
}
/* check with suffix */
if (strncmp(cur, suffix, strlen(suffix))) {
pr_warn("crashkernel: unrecognized char\n");
return -EINVAL;
}
cur += strlen(suffix);
if (*cur != ' ' && *cur != '\0') {
pr_warn("crashkernel: unrecognized char\n");
return -EINVAL;
}
return 0;
}
static __init char *get_last_crashkernel(char *cmdline,
const char *name,
const char *suffix)
{
char *p = cmdline, *ck_cmdline = NULL;
/* find crashkernel and use the last one if there are more */
p = strstr(p, name);
while (p) {
char *end_p = strchr(p, ' ');
char *q;
if (!end_p)
end_p = p + strlen(p);
if (!suffix) {
int i;
/* skip the one with any known suffix */
for (i = 0; suffix_tbl[i]; i++) {
q = end_p - strlen(suffix_tbl[i]);
if (!strncmp(q, suffix_tbl[i],
strlen(suffix_tbl[i])))
goto next;
}
ck_cmdline = p;
} else {
q = end_p - strlen(suffix);
if (!strncmp(q, suffix, strlen(suffix)))
ck_cmdline = p;
}
next:
p = strstr(p+1, name);
}
if (!ck_cmdline)
return NULL;
return ck_cmdline;
}
static int __init __parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base,
const char *name,
const char *suffix)
{
char *first_colon, *first_space;
char *ck_cmdline;
BUG_ON(!crash_size || !crash_base);
*crash_size = 0;
*crash_base = 0;
ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
if (!ck_cmdline)
return -EINVAL;
ck_cmdline += strlen(name);
if (suffix)
return parse_crashkernel_suffix(ck_cmdline, crash_size,
suffix);
/*
* if the commandline contains a ':', then that's the extended
* syntax -- if not, it must be the classic syntax
*/
first_colon = strchr(ck_cmdline, ':');
first_space = strchr(ck_cmdline, ' ');
if (first_colon && (!first_space || first_colon < first_space))
return parse_crashkernel_mem(ck_cmdline, system_ram,
crash_size, crash_base);
return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
}
/*
* That function is the entry point for command line parsing and should be
* called from the arch-specific code.
*/
int __init parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
"crashkernel=", NULL);
}
int __init parse_crashkernel_high(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
"crashkernel=", suffix_tbl[SUFFIX_HIGH]);
}
int __init parse_crashkernel_low(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
"crashkernel=", suffix_tbl[SUFFIX_LOW]);
}
static void update_vmcoreinfo_note(void)
{
u32 *buf = vmcoreinfo_note;
if (!vmcoreinfo_size)
return;
buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
vmcoreinfo_size);
final_note(buf);
}
void crash_save_vmcoreinfo(void)
{
vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds());
update_vmcoreinfo_note();
}
void vmcoreinfo_append_str(const char *fmt, ...)
{
va_list args;
char buf[0x50];
size_t r;
va_start(args, fmt);
r = vscnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
r = min(r, vmcoreinfo_max_size - vmcoreinfo_size);
memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
vmcoreinfo_size += r;
}
/*
* provide an empty default implementation here -- architecture
* code may override this
*/
void __weak arch_crash_save_vmcoreinfo(void)
{}
unsigned long __weak paddr_vmcoreinfo_note(void)
{
return __pa((unsigned long)(char *)&vmcoreinfo_note);
}
static int __init crash_save_vmcoreinfo_init(void)
{
VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
VMCOREINFO_PAGESIZE(PAGE_SIZE);
VMCOREINFO_SYMBOL(init_uts_ns);
VMCOREINFO_SYMBOL(node_online_map);
#ifdef CONFIG_MMU
VMCOREINFO_SYMBOL(swapper_pg_dir);
#endif
VMCOREINFO_SYMBOL(_stext);
VMCOREINFO_SYMBOL(vmap_area_list);
#ifndef CONFIG_NEED_MULTIPLE_NODES
VMCOREINFO_SYMBOL(mem_map);
VMCOREINFO_SYMBOL(contig_page_data);
#endif
#ifdef CONFIG_SPARSEMEM
VMCOREINFO_SYMBOL(mem_section);
VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
VMCOREINFO_STRUCT_SIZE(mem_section);
VMCOREINFO_OFFSET(mem_section, section_mem_map);
#endif
VMCOREINFO_STRUCT_SIZE(page);
VMCOREINFO_STRUCT_SIZE(pglist_data);
VMCOREINFO_STRUCT_SIZE(zone);
VMCOREINFO_STRUCT_SIZE(free_area);
VMCOREINFO_STRUCT_SIZE(list_head);
VMCOREINFO_SIZE(nodemask_t);
VMCOREINFO_OFFSET(page, flags);
VMCOREINFO_OFFSET(page, _count);
VMCOREINFO_OFFSET(page, mapping);
VMCOREINFO_OFFSET(page, lru);
VMCOREINFO_OFFSET(page, _mapcount);
VMCOREINFO_OFFSET(page, private);
VMCOREINFO_OFFSET(pglist_data, node_zones);
VMCOREINFO_OFFSET(pglist_data, nr_zones);
#ifdef CONFIG_FLAT_NODE_MEM_MAP
VMCOREINFO_OFFSET(pglist_data, node_mem_map);
#endif
VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
VMCOREINFO_OFFSET(pglist_data, node_id);
VMCOREINFO_OFFSET(zone, free_area);
VMCOREINFO_OFFSET(zone, vm_stat);
VMCOREINFO_OFFSET(zone, spanned_pages);
VMCOREINFO_OFFSET(free_area, free_list);
VMCOREINFO_OFFSET(list_head, next);
VMCOREINFO_OFFSET(list_head, prev);
VMCOREINFO_OFFSET(vmap_area, va_start);
VMCOREINFO_OFFSET(vmap_area, list);
VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
log_buf_kexec_setup();
VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
VMCOREINFO_NUMBER(NR_FREE_PAGES);
VMCOREINFO_NUMBER(PG_lru);
VMCOREINFO_NUMBER(PG_private);
VMCOREINFO_NUMBER(PG_swapcache);
VMCOREINFO_NUMBER(PG_slab);
#ifdef CONFIG_MEMORY_FAILURE
VMCOREINFO_NUMBER(PG_hwpoison);
#endif
VMCOREINFO_NUMBER(PG_head_mask);
VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
#ifdef CONFIG_HUGETLBFS
VMCOREINFO_SYMBOL(free_huge_page);
#endif
arch_crash_save_vmcoreinfo();
update_vmcoreinfo_note();
return 0;
}
subsys_initcall(crash_save_vmcoreinfo_init);
/*
* Move into place and start executing a preloaded standalone
* executable. If nothing was preloaded return an error.
*/
int kernel_kexec(void)
{
int error = 0;
if (!mutex_trylock(&kexec_mutex))
return -EBUSY;
if (!kexec_image) {
error = -EINVAL;
goto Unlock;
}
#ifdef CONFIG_KEXEC_JUMP
if (kexec_image->preserve_context) {
lock_system_sleep();
pm_prepare_console();
error = freeze_processes();
if (error) {
error = -EBUSY;
goto Restore_console;
}
suspend_console();
error = dpm_suspend_start(PMSG_FREEZE);
if (error)
goto Resume_console;
/* At this point, dpm_suspend_start() has been called,
* but *not* dpm_suspend_end(). We *must* call
* dpm_suspend_end() now. Otherwise, drivers for
* some devices (e.g. interrupt controllers) become
* desynchronized with the actual state of the
* hardware at resume time, and evil weirdness ensues.
*/
error = dpm_suspend_end(PMSG_FREEZE);
if (error)
goto Resume_devices;
error = disable_nonboot_cpus();
if (error)
goto Enable_cpus;
local_irq_disable();
error = syscore_suspend();
if (error)
goto Enable_irqs;
} else
#endif
{
kexec_in_progress = true;
kernel_restart_prepare(NULL);
migrate_to_reboot_cpu();
/*
* migrate_to_reboot_cpu() disables CPU hotplug assuming that
* no further code needs to use CPU hotplug (which is true in
* the reboot case). However, the kexec path depends on using
* CPU hotplug again; so re-enable it here.
*/
cpu_hotplug_enable();
pr_emerg("Starting new kernel\n");
machine_shutdown();
}
machine_kexec(kexec_image);
#ifdef CONFIG_KEXEC_JUMP
if (kexec_image->preserve_context) {
syscore_resume();
Enable_irqs:
local_irq_enable();
Enable_cpus:
enable_nonboot_cpus();
dpm_resume_start(PMSG_RESTORE);
Resume_devices:
dpm_resume_end(PMSG_RESTORE);
Resume_console:
resume_console();
thaw_processes();
Restore_console:
pm_restore_console();
unlock_system_sleep();
}
#endif
Unlock:
mutex_unlock(&kexec_mutex);
return error;
}
/*
* Add and remove page tables for crashkernel memory
*
* Provide an empty default implementation here -- architecture
* code may override this
*/
void __weak crash_map_reserved_pages(void)
{}
void __weak crash_unmap_reserved_pages(void)
{}