[PATCH v8 04/13] x86: kexec_file: factor out elf core header related functions
AKASHI Takahiro
takahiro.akashi at linaro.org
Thu Feb 22 03:17:23 PST 2018
exclude_mem_range() and prepare_elf64_headers() can be re-used on other
architectures, including arm64, as well. So let them factored out so as to
move them to generic side in the next patch.
fill_up_crash_elf_data() can potentially be commonalized for most
architectures who want to go through io resources (/proc/iomem) for a list
of "System RAM", but leave it private for now.
Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
Cc: Dave Young <dyoung at redhat.com>
Cc: Vivek Goyal <vgoyal at redhat.com>
Cc: Baoquan He <bhe at redhat.com>
---
arch/x86/kernel/crash.c | 235 +++++++++++++++++++++---------------------------
1 file changed, 103 insertions(+), 132 deletions(-)
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 10e74d4778a1..5c19cfbf3b85 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -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 */
@@ -217,29 +199,32 @@ 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);
- 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 = vmalloc(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,
+static int crash_exclude_mem_range(struct crash_mem *mem,
unsigned long long mstart, unsigned long long mend)
{
int i, j;
@@ -293,10 +278,8 @@ 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;
@@ -314,27 +297,20 @@ 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,
- unsigned long long mstart, unsigned long long mend)
+static int elf_header_exclude_ranges(struct crash_mem *cmem)
{
- struct crash_mem *cmem = &ced->mem;
int ret = 0;
- memset(cmem->ranges, 0, sizeof(cmem->ranges));
-
- cmem->ranges[0].start = mstart;
- cmem->ranges[0].end = mend;
- cmem->nr_ranges = 1;
-
/* Exclude crashkernel region */
- ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+ ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
if (ret)
return ret;
if (crashk_low_res.end) {
- ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
+ ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
+ crashk_low_res.end);
if (ret)
return ret;
}
@@ -344,70 +320,29 @@ 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;
- Elf64_Ehdr *ehdr;
- Elf64_Phdr *phdr;
- unsigned long mstart, mend;
- struct kimage *image = ced->image;
- struct crash_mem *cmem;
- int ret, i;
+ struct crash_mem *cmem = arg;
- ehdr = ced->ehdr;
-
- /* Exclude unwanted mem ranges */
- ret = elf_header_exclude_ranges(ced, res->start, res->end);
- if (ret)
- return ret;
-
- /* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
- cmem = &ced->mem;
-
- for (i = 0; i < cmem->nr_ranges; i++) {
- mstart = cmem->ranges[i].start;
- mend = cmem->ranges[i].end;
-
- phdr = ced->bufp;
- ced->bufp += sizeof(Elf64_Phdr);
-
- phdr->p_type = PT_LOAD;
- phdr->p_flags = PF_R|PF_W|PF_X;
- phdr->p_offset = mstart;
-
- /*
- * If a range matches backup region, adjust offset to backup
- * segment.
- */
- if (mstart == image->arch.backup_src_start &&
- (mend - mstart + 1) == image->arch.backup_src_sz)
- phdr->p_offset = image->arch.backup_load_addr;
-
- phdr->p_paddr = mstart;
- phdr->p_vaddr = (unsigned long long) __va(mstart);
- phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
- phdr->p_align = 0;
- ehdr->e_phnum++;
- pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
- phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
- ehdr->e_phnum, phdr->p_offset);
- }
+ cmem->ranges[cmem->nr_ranges].start = res->start;
+ cmem->ranges[cmem->nr_ranges].end = res->end;
+ cmem->nr_ranges++;
- return ret;
+ return 0;
}
-static int prepare_elf64_headers(struct crash_elf_data *ced,
- void **addr, unsigned long *sz)
+static int crash_prepare_elf64_headers(struct crash_mem *cmem, int kernel_map,
+ void **addr, unsigned long *sz)
{
Elf64_Ehdr *ehdr;
Elf64_Phdr *phdr;
unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
- unsigned char *buf, *bufp;
- unsigned int cpu;
+ unsigned char *buf;
+ unsigned int cpu, i;
unsigned long long notes_addr;
- int ret;
+ 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
@@ -425,9 +360,8 @@ static int prepare_elf64_headers(struct crash_elf_data *ced,
if (!buf)
return -ENOMEM;
- bufp = buf;
- ehdr = (Elf64_Ehdr *)bufp;
- bufp += sizeof(Elf64_Ehdr);
+ ehdr = (Elf64_Ehdr *)buf;
+ phdr = (Elf64_Phdr *)(ehdr + 1);
memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
ehdr->e_ident[EI_CLASS] = ELFCLASS64;
ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
@@ -443,42 +377,51 @@ static int prepare_elf64_headers(struct crash_elf_data *ced,
/* Prepare one phdr of type PT_NOTE for each present cpu */
for_each_present_cpu(cpu) {
- phdr = (Elf64_Phdr *)bufp;
- bufp += sizeof(Elf64_Phdr);
phdr->p_type = PT_NOTE;
notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
phdr->p_offset = phdr->p_paddr = notes_addr;
phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
(ehdr->e_phnum)++;
+ phdr++;
}
/* Prepare one PT_NOTE header for vmcoreinfo */
- phdr = (Elf64_Phdr *)bufp;
- bufp += sizeof(Elf64_Phdr);
phdr->p_type = PT_NOTE;
phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
(ehdr->e_phnum)++;
+ phdr++;
-#ifdef CONFIG_X86_64
/* Prepare PT_LOAD type program header for kernel text region */
- phdr = (Elf64_Phdr *)bufp;
- bufp += sizeof(Elf64_Phdr);
- phdr->p_type = PT_LOAD;
- phdr->p_flags = PF_R|PF_W|PF_X;
- phdr->p_vaddr = (Elf64_Addr)_text;
- phdr->p_filesz = phdr->p_memsz = _end - _text;
- phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
- (ehdr->e_phnum)++;
-#endif
+ if (kernel_map) {
+ phdr->p_type = PT_LOAD;
+ phdr->p_flags = PF_R|PF_W|PF_X;
+ phdr->p_vaddr = (Elf64_Addr)_text;
+ phdr->p_filesz = phdr->p_memsz = _end - _text;
+ phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
+ ehdr->e_phnum++;
+ phdr++;
+ }
- /* Prepare PT_LOAD headers for system ram chunks. */
- ced->ehdr = ehdr;
- ced->bufp = bufp;
- ret = walk_system_ram_res(0, -1, ced,
- prepare_elf64_ram_headers_callback);
- if (ret < 0)
- return ret;
+ /* Go through all the ranges in cmem->ranges[] and prepare phdr */
+ for (i = 0; i < cmem->nr_ranges; i++) {
+ mstart = cmem->ranges[i].start;
+ mend = cmem->ranges[i].end;
+
+ phdr->p_type = PT_LOAD;
+ phdr->p_flags = PF_R|PF_W|PF_X;
+ phdr->p_offset = mstart;
+
+ phdr->p_paddr = mstart;
+ phdr->p_vaddr = (unsigned long long) __va(mstart);
+ phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
+ phdr->p_align = 0;
+ ehdr->e_phnum++;
+ phdr++;
+ pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
+ phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
+ ehdr->e_phnum, phdr->p_offset);
+ }
*addr = buf;
*sz = elf_sz;
@@ -489,18 +432,46 @@ static int prepare_elf64_headers(struct crash_elf_data *ced,
static int prepare_elf_headers(struct kimage *image, void **addr,
unsigned long *sz)
{
- struct crash_elf_data *ced;
- int ret;
+ 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, cmem,
+ prepare_elf64_ram_headers_callback);
+ if (ret)
+ goto out;
+
+ /* Exclude unwanted mem ranges */
+ ret = elf_header_exclude_ranges(cmem);
+ if (ret)
+ goto out;
/* By default prepare 64bit headers */
- ret = prepare_elf64_headers(ced, addr, sz);
- kfree(ced);
+ ret = crash_prepare_elf64_headers(cmem,
+ (int)IS_ENABLED(CONFIG_X86_64), addr, sz);
+ if (ret)
+ goto out;
+
+ /*
+ * If a range matches backup region, adjust offset to backup
+ * segment.
+ */
+ ehdr = (Elf64_Ehdr *)*addr;
+ phdr = (Elf64_Phdr *)(ehdr + 1);
+ for (i = 0; i < ehdr->e_phnum; phdr++, i++)
+ if (phdr->p_type == PT_LOAD &&
+ phdr->p_paddr == image->arch.backup_src_start &&
+ phdr->p_memsz == image->arch.backup_src_sz) {
+ phdr->p_offset = image->arch.backup_load_addr;
+ break;
+ }
+out:
+ vfree(cmem);
return ret;
}
@@ -546,14 +517,14 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
/* Exclude Backup region */
start = image->arch.backup_load_addr;
end = start + image->arch.backup_src_sz - 1;
- ret = exclude_mem_range(cmem, start, end);
+ ret = crash_exclude_mem_range(cmem, start, end);
if (ret)
return ret;
/* Exclude elf header region */
start = image->arch.elf_load_addr;
end = start + image->arch.elf_headers_sz - 1;
- return exclude_mem_range(cmem, start, end);
+ return crash_exclude_mem_range(cmem, start, end);
}
/* Prepare memory map for crash dump kernel */
--
2.16.2
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