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x86/crash: Use crash_prepare_headers() helper to simplify code

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Use the newly introduced crash_prepare_headers() function to replace
the existing prepare_elf_headers(), allocate cmem and exclude crash kernel
memory in the crash core, which reduce code duplication.

Only the following three architecture functions need to be implemented:
- arch_get_system_nr_ranges(). Call get_nr_ram_ranges_callback()
  to pre-count the max number of memory ranges.

- arch_crash_populate_cmem(). Use prepare_elf64_ram_headers_callback()
  to collect the memory ranges and fills them into cmem.

- arch_crash_exclude_ranges(). Exclude the low 1M for x86.

While at it, remove the unused "nr_mem_ranges" in
arch_crash_handle_hotplug_event().

Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://patch.msgid.link/20260629094746.191843-6-ruanjinjie@huawei.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
This commit is contained in:
Jinjie Ruan 2026-06-29 17:47:41 +08:00 committed by Mike Rapoport (Microsoft)
parent 201b561cbc
commit a8f09f2a74
1 changed files with 11 additions and 78 deletions
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89
arch/x86/kernel/crash.c
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@ -155,16 +155,8 @@ 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 struct crash_mem *fill_up_crash_elf_data(void)
unsigned int arch_get_system_nr_ranges(void)
{
unsigned int nr_ranges = 0;
struct crash_mem *cmem;
walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
if (!nr_ranges)
return NULL;
/*
* Exclusion of crash region, crashk_low_res and/or crashk_cma_ranges
* may cause range splits. So add extra slots here.
@ -179,49 +171,16 @@ static struct crash_mem *fill_up_crash_elf_data(void)
* But in order to lest the low 1M could be changed in the future,
* (e.g. [start, 1M]), add a extra slot.
*/
nr_ranges += 3 + crashk_cma_cnt;
cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
if (!cmem)
return NULL;
unsigned int nr_ranges = 3 + crashk_cma_cnt;
cmem->max_nr_ranges = nr_ranges;
return cmem;
walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
return nr_ranges;
}
/*
* Look for any unwanted ranges between mstart, mend and remove them. This
* might lead to split and split ranges are put in cmem->ranges[] array
*/
static int elf_header_exclude_ranges(struct crash_mem *cmem)
int arch_crash_exclude_ranges(struct crash_mem *cmem)
{
int ret = 0;
int i;
/* Exclude the low 1M because it is always reserved */
ret = crash_exclude_mem_range(cmem, 0, SZ_1M - 1);
if (ret)
return ret;
/* Exclude crashkernel region */
ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
if (ret)
return ret;
if (crashk_low_res.end)
ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
crashk_low_res.end);
if (ret)
return ret;
for (i = 0; i < crashk_cma_cnt; ++i) {
ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start,
crashk_cma_ranges[i].end);
if (ret)
return ret;
}
return 0;
return crash_exclude_mem_range(cmem, 0, SZ_1M - 1);
}
static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
@ -235,35 +194,9 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
return 0;
}
/* Prepare elf headers. Return addr and size */
static int prepare_elf_headers(void **addr, unsigned long *sz,
unsigned long *nr_mem_ranges)
int arch_crash_populate_cmem(struct crash_mem *cmem)
{
struct crash_mem *cmem;
int ret;
cmem = fill_up_crash_elf_data();
if (!cmem)
return -ENOMEM;
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(cmem);
if (ret)
goto out;
/* Return the computed number of memory ranges, for hotplug usage */
*nr_mem_ranges = cmem->nr_ranges;
/* By default prepare 64bit headers */
ret = crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz);
out:
vfree(cmem);
return ret;
return walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
}
#endif
@ -421,7 +354,8 @@ int crash_load_segments(struct kimage *image)
.buf_max = ULONG_MAX, .top_down = false };
/* Prepare elf headers and add a segment */
ret = prepare_elf_headers(&kbuf.buffer, &kbuf.bufsz, &pnum);
ret = crash_prepare_headers(IS_ENABLED(CONFIG_X86_64), &kbuf.buffer,
&kbuf.bufsz, &pnum);
if (ret)
return ret;
@ -514,7 +448,6 @@ unsigned int arch_crash_get_elfcorehdr_size(void)
void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)
{
void *elfbuf = NULL, *old_elfcorehdr;
unsigned long nr_mem_ranges;
unsigned long mem, memsz;
unsigned long elfsz = 0;
@ -532,7 +465,7 @@ void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)
* Create the new elfcorehdr reflecting the changes to CPU and/or
* memory resources.
*/
if (prepare_elf_headers(&elfbuf, &elfsz, &nr_mem_ranges)) {
if (crash_prepare_headers(IS_ENABLED(CONFIG_X86_64), &elfbuf, &elfsz, NULL)) {
pr_err("unable to create new elfcorehdr");
goto out;
}