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x86: kexec_file: lift CRASH_MAX_RANGES limit on crash_mem buffer

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While CRASH_MAX_RANGES (== 16) seems to be good enough, fixed-number
array is not a good idea in general.

In this patch, size of crash_mem buffer is calculated as before and the
buffer is now dynamically allocated.  This change also allows removing
crash_elf_data structure.

Link: http://lkml.kernel.org/r/20180306102303.9063-6-takahiro.akashi@linaro.org
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Dave Young <dyoung@redhat.com>
Tested-by: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
AKASHI Takahiro 2018-04-13 15:35:59 -07:00 committed by Linus Torvalds
parent c72c7e6709
commit 8d5f894a31
1 changed files with 31 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

82
arch/x86/kernel/crash.c
View File

@ -41,32 +41,14 @@
/* Alignment required for elf header segment */
#define ELF_CORE_HEADER_ALIGN 4096
/* This primarily represents number of split ranges due to exclusion */
#define CRASH_MAX_RANGES 16
struct crash_mem_range {
u64 start, end;
};
struct crash_mem {
unsigned int nr_ranges;
struct crash_mem_range ranges[CRASH_MAX_RANGES];
};
/* Misc data about ram ranges needed to prepare elf headers */
struct crash_elf_data {
struct kimage *image;
/*
* Total number of ram ranges we have after various adjustments for
* crash reserved region, etc.
*/
unsigned int max_nr_ranges;
/* Pointer to elf header */
void *ehdr;
/* Pointer to next phdr */
void *bufp;
struct crash_mem mem;
unsigned int nr_ranges;
struct crash_mem_range ranges[0];
};
/* Used while preparing memory map entries for second kernel */
@ -218,26 +200,31 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
return 0;
}
/* Gather all the required information to prepare elf headers for ram regions */
static void fill_up_crash_elf_data(struct crash_elf_data *ced,
struct kimage *image)
static struct crash_mem *fill_up_crash_elf_data(void)
{
unsigned int nr_ranges = 0;
ced->image = image;
struct crash_mem *cmem;
walk_system_ram_res(0, -1, &nr_ranges,
get_nr_ram_ranges_callback);
if (!nr_ranges)
return NULL;
ced->max_nr_ranges = nr_ranges;
/*
* Exclusion of crash region and/or crashk_low_res may cause
* another range split. So add extra two slots here.
*/
nr_ranges += 2;
cmem = vzalloc(sizeof(struct crash_mem) +
sizeof(struct crash_mem_range) * nr_ranges);
if (!cmem)
return NULL;
/* Exclusion of crash region could split memory ranges */
ced->max_nr_ranges++;
cmem->max_nr_ranges = nr_ranges;
cmem->nr_ranges = 0;
/* If crashk_low_res is not 0, another range split possible */
if (crashk_low_res.end)
ced->max_nr_ranges++;
return cmem;
}
static int exclude_mem_range(struct crash_mem *mem,
@ -294,10 +281,8 @@ static int exclude_mem_range(struct crash_mem *mem,
return 0;
/* Split happened */
if (i == CRASH_MAX_RANGES - 1) {
pr_err("Too many crash ranges after split\n");
if (i == mem->max_nr_ranges - 1)
return -ENOMEM;
}
/* Location where new range should go */
j = i + 1;
@ -315,11 +300,10 @@ static int exclude_mem_range(struct crash_mem *mem,
/*
* Look for any unwanted ranges between mstart, mend and remove them. This
* might lead to split and split ranges are put in ced->mem.ranges[] array
* might lead to split and split ranges are put in cmem->ranges[] array
*/
static int elf_header_exclude_ranges(struct crash_elf_data *ced)
static int elf_header_exclude_ranges(struct crash_mem *cmem)
{
struct crash_mem *cmem = &ced->mem;
int ret = 0;
/* Exclude crashkernel region */
@ -338,8 +322,7 @@ static int elf_header_exclude_ranges(struct crash_elf_data *ced)
static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
{
struct crash_elf_data *ced = arg;
struct crash_mem *cmem = &ced->mem;
struct crash_mem *cmem = arg;
cmem->ranges[cmem->nr_ranges].start = res->start;
cmem->ranges[cmem->nr_ranges].end = res->end;
@ -348,7 +331,7 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
return 0;
}
static int prepare_elf64_headers(struct crash_elf_data *ced, bool kernel_map,
static int prepare_elf64_headers(struct crash_mem *cmem, bool kernel_map,
void **addr, unsigned long *sz)
{
Elf64_Ehdr *ehdr;
@ -357,12 +340,11 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, bool kernel_map,
unsigned char *buf, *bufp;
unsigned int cpu, i;
unsigned long long notes_addr;
struct crash_mem *cmem = &ced->mem;
unsigned long mstart, mend;
/* extra phdr for vmcoreinfo elf note */
nr_phdr = nr_cpus + 1;
nr_phdr += ced->max_nr_ranges;
nr_phdr += cmem->nr_ranges;
/*
* kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
@ -456,29 +438,27 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, bool kernel_map,
static int prepare_elf_headers(struct kimage *image, void **addr,
unsigned long *sz)
{
struct crash_elf_data *ced;
struct crash_mem *cmem;
Elf64_Ehdr *ehdr;
Elf64_Phdr *phdr;
int ret, i;
ced = kzalloc(sizeof(*ced), GFP_KERNEL);
if (!ced)
cmem = fill_up_crash_elf_data();
if (!cmem)
return -ENOMEM;
fill_up_crash_elf_data(ced, image);
ret = walk_system_ram_res(0, -1, ced,
ret = walk_system_ram_res(0, -1, cmem,
prepare_elf64_ram_headers_callback);
if (ret)
goto out;
/* Exclude unwanted mem ranges */
ret = elf_header_exclude_ranges(ced);
ret = elf_header_exclude_ranges(cmem);
if (ret)
goto out;
/* By default prepare 64bit headers */
ret = prepare_elf64_headers(ced, IS_ENABLED(CONFIG_X86_64), addr, sz);
ret = prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz);
if (ret)
goto out;
@ -496,7 +476,7 @@ static int prepare_elf_headers(struct kimage *image, void **addr,
break;
}
out:
kfree(ced);
vfree(cmem);
return ret;
}