o For i386, Physical memory upto 896MB is linearly mapped. Hence virtual
addresses for linearly mapped region are known.
o This patch sets the appropriate virtual addresses in core headers for
linearly mapped region.
o Enables gdb to debug linearly mapped region without any special user space
utility. Otherwise, capture tools first need to analyze the core image (Read
page tables and/or vm areas) and determine virtual addresses for memory
chunks and then regenerate the elf headers suitable for debugging with gdb.
o Some cases like 4G/4G split deviate from 896MB linearly mapped region and
might have different value for PAGE_OFFSET. Probably its a good idea to
export the linear region from kernel and use that instead of hard coding it.
Signed-off-by: Vivek Goyal <[email protected]>
---
kexec-tools-1.101-root/kexec/arch/i386/crashdump-x86.c | 26 +++++++++++++++--
kexec-tools-1.101-root/kexec/arch/i386/crashdump-x86.h | 3 +
2 files changed, 27 insertions(+), 2 deletions(-)
diff -puN kexec/arch/i386/crashdump-x86.c~kexec-tools-linearly-mapped-region-x86 kexec/arch/i386/crashdump-x86.c
--- kexec-tools-1.101/kexec/arch/i386/crashdump-x86.c~kexec-tools-linearly-mapped-region-x86 2005-03-21 18:55:18.000000000 +0530
+++ kexec-tools-1.101-root/kexec/arch/i386/crashdump-x86.c 2005-03-21 18:59:07.000000000 +0530
@@ -106,10 +106,22 @@ int get_crash_memory_ranges(struct memor
/* First 640K already registered */
if (start >= 0x00000000 && end <= 0x0009ffff)
continue;
+
crash_memory_range[memory_ranges].start = start;
crash_memory_range[memory_ranges].end = end;
crash_memory_range[memory_ranges].type = type;
memory_ranges++;
+
+ /* Segregate linearly mapped region. */
+ if ((MAXMEM - 1) >= start && (MAXMEM - 1) <= end) {
+ crash_memory_range[memory_ranges-1].end = MAXMEM -1;
+
+ /* Add segregated region. */
+ crash_memory_range[memory_ranges].start = MAXMEM;
+ crash_memory_range[memory_ranges].end = end;
+ crash_memory_range[memory_ranges].type = type;
+ memory_ranges++;
+ }
}
fclose(fp);
if (exclude_crash_reserve_region(&memory_ranges) < 0)
@@ -521,7 +533,12 @@ int prepare_crash_memory_elf64_headers(s
phdr->p_offset = info->backup_start;
else
phdr->p_offset = mstart;
- phdr->p_vaddr = phdr->p_paddr = mstart;
+ /* Handle linearly mapped region.*/
+ if (mend <= (MAXMEM - 1))
+ phdr->p_vaddr = mstart + PAGE_OFFSET;
+ else
+ phdr->p_vaddr = -1ULL;
+ phdr->p_paddr = mstart;
phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
/* Do we need any alignment of segments? */
phdr->p_align = 0;
@@ -612,7 +629,12 @@ int prepare_crash_memory_elf32_headers(s
phdr->p_offset = info->backup_start;
else
phdr->p_offset = mstart;
- phdr->p_vaddr = phdr->p_paddr = mstart;
+ /* Handle linearly mapped region.*/
+ if (mend <= (MAXMEM - 1))
+ phdr->p_vaddr = mstart + PAGE_OFFSET;
+ else
+ phdr->p_vaddr = ULONG_MAX;
+ phdr->p_paddr = mstart;
phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
/* Do we need any alignment of segments? */
phdr->p_align = 0;
diff -puN kexec/arch/i386/crashdump-x86.h~kexec-tools-linearly-mapped-region-x86 kexec/arch/i386/crashdump-x86.h
--- kexec-tools-1.101/kexec/arch/i386/crashdump-x86.h~kexec-tools-linearly-mapped-region-x86 2005-03-21 18:55:18.000000000 +0530
+++ kexec-tools-1.101-root/kexec/arch/i386/crashdump-x86.h 2005-03-21 18:55:18.000000000 +0530
@@ -18,6 +18,9 @@ extern struct memory_range crash_reserve
#define PAGE_OFFSET 0xc0000000
#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET)
+#define __VMALLOC_RESERVE (128 << 20)
+#define MAXMEM (-PAGE_OFFSET-__VMALLOC_RESERVE)
+
#define CRASH_MAX_MEMMAP_NR (KEXEC_MAX_SEGMENTS + 1)
#define CRASH_MAX_MEMORY_RANGES (MAX_MEMORY_RANGES + 2)
_
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