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arm64: kexec_file: add crash dump support

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Enabling crash dump (kdump) includes
* prepare contents of ELF header of a core dump file, /proc/vmcore,
  using crash_prepare_elf64_headers(), and
* add two device tree properties, "linux,usable-memory-range" and
  "linux,elfcorehdr", which represent respectively a memory range
  to be used by crash dump kernel and the header's location

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Tested-and-reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
AKASHI Takahiro 2019-12-16 11:12:47 +09:00 committed by Will Deacon
parent c273a2bd8a
commit 3751e728ce
3 changed files with 106 additions and 8 deletions
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4
arch/arm64/include/asm/kexec.h
View file

@ -96,6 +96,10 @@ static inline void crash_post_resume(void) {}
struct kimage_arch {
void *dtb;
unsigned long dtb_mem;
/* Core ELF header buffer */
void *elf_headers;
unsigned long elf_headers_mem;
unsigned long elf_headers_sz;
};
extern const struct kexec_file_ops kexec_image_ops;

4
arch/arm64/kernel/kexec_image.c
View file

@ -47,10 +47,6 @@ static void *image_load(struct kimage *image,
struct kexec_segment *kernel_segment;
int ret;
/* We don't support crash kernels yet. */
if (image->type == KEXEC_TYPE_CRASH)
return ERR_PTR(-EOPNOTSUPP);
/*
* We require a kernel with an unambiguous Image header. Per
* Documentation/arm64/booting.rst, this is the case when image_size

106
arch/arm64/kernel/machine_kexec_file.c
View file

@ -17,12 +17,15 @@
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <asm/byteorder.h>
/* relevant device tree properties */
#define FDT_PROP_KEXEC_ELFHDR "linux,elfcorehdr"
#define FDT_PROP_MEM_RANGE "linux,usable-memory-range"
#define FDT_PROP_INITRD_START "linux,initrd-start"
#define FDT_PROP_INITRD_END "linux,initrd-end"
#define FDT_PROP_BOOTARGS "bootargs"
@ -40,6 +43,10 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
vfree(image->arch.dtb);
image->arch.dtb = NULL;
vfree(image->arch.elf_headers);
image->arch.elf_headers = NULL;
image->arch.elf_headers_sz = 0;
return kexec_image_post_load_cleanup_default(image);
}
@ -55,6 +62,31 @@ static int setup_dtb(struct kimage *image,
off = ret;
ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);
if (ret && ret != -FDT_ERR_NOTFOUND)
goto out;
ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);
if (ret && ret != -FDT_ERR_NOTFOUND)
goto out;
if (image->type == KEXEC_TYPE_CRASH) {
/* add linux,elfcorehdr */
ret = fdt_appendprop_addrrange(dtb, 0, off,
FDT_PROP_KEXEC_ELFHDR,
image->arch.elf_headers_mem,
image->arch.elf_headers_sz);
if (ret)
return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
/* add linux,usable-memory-range */
ret = fdt_appendprop_addrrange(dtb, 0, off,
FDT_PROP_MEM_RANGE,
crashk_res.start,
crashk_res.end - crashk_res.start + 1);
if (ret)
return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
}
/* add bootargs */
if (cmdline) {
ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);
@ -125,8 +157,8 @@ static int setup_dtb(struct kimage *image,
}
/*
* More space needed so that we can add initrd, bootargs, kaslr-seed, and
* rng-seed.
* More space needed so that we can add initrd, bootargs, kaslr-seed,
* rng-seed, userable-memory-range and elfcorehdr.
*/
#define DTB_EXTRA_SPACE 0x1000
@ -174,6 +206,43 @@ static int create_dtb(struct kimage *image,
}
}
static int prepare_elf_headers(void **addr, unsigned long *sz)
{
struct crash_mem *cmem;
unsigned int nr_ranges;
int ret;
u64 i;
phys_addr_t start, end;
nr_ranges = 1; /* for exclusion of crashkernel region */
for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,
MEMBLOCK_NONE, &start, &end, NULL)
nr_ranges++;
cmem = kmalloc(sizeof(struct crash_mem) +
sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL);
if (!cmem)
return -ENOMEM;
cmem->max_nr_ranges = nr_ranges;
cmem->nr_ranges = 0;
for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,
MEMBLOCK_NONE, &start, &end, NULL) {
cmem->ranges[cmem->nr_ranges].start = start;
cmem->ranges[cmem->nr_ranges].end = end - 1;
cmem->nr_ranges++;
}
/* Exclude crashkernel region */
ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
if (!ret)
ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
kfree(cmem);
return ret;
}
int load_other_segments(struct kimage *image,
unsigned long kernel_load_addr,
unsigned long kernel_size,
@ -181,14 +250,43 @@ int load_other_segments(struct kimage *image,
char *cmdline)
{
struct kexec_buf kbuf;
void *dtb = NULL;
unsigned long initrd_load_addr = 0, dtb_len;
void *headers, *dtb = NULL;
unsigned long headers_sz, initrd_load_addr = 0, dtb_len;
int ret = 0;
kbuf.image = image;
/* not allocate anything below the kernel */
kbuf.buf_min = kernel_load_addr + kernel_size;
/* load elf core header */
if (image->type == KEXEC_TYPE_CRASH) {
ret = prepare_elf_headers(&headers, &headers_sz);
if (ret) {
pr_err("Preparing elf core header failed\n");
goto out_err;
}
kbuf.buffer = headers;
kbuf.bufsz = headers_sz;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
kbuf.memsz = headers_sz;
kbuf.buf_align = SZ_64K; /* largest supported page size */
kbuf.buf_max = ULONG_MAX;
kbuf.top_down = true;
ret = kexec_add_buffer(&kbuf);
if (ret) {
vfree(headers);
goto out_err;
}
image->arch.elf_headers = headers;
image->arch.elf_headers_mem = kbuf.mem;
image->arch.elf_headers_sz = headers_sz;
pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
image->arch.elf_headers_mem, headers_sz, headers_sz);
}
/* load initrd */
if (initrd) {
kbuf.buffer = initrd;