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| author | Vivek Goyal <vgoyal@in.ibm.com> | 2005-06-25 14:58:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-06-25 16:24:52 -0700 |
| commit | 92aa63a5a1bf2e7b0c79e6716d24b76dbbdcf951 (patch) | |
| tree | 1f4d49c8e9bf02e834e6af8c1f7d4484d9f76c6e | |
| parent | d58831e4163699de204dea199be2e903bf5d6eff (diff) | |
| download | op-kernel-dev-92aa63a5a1bf2e7b0c79e6716d24b76dbbdcf951.zip op-kernel-dev-92aa63a5a1bf2e7b0c79e6716d24b76dbbdcf951.tar.gz | |
[PATCH] kdump: Retrieve saved max pfn
This patch retrieves the max_pfn being used by previous kernel and stores it
in a safe location (saved_max_pfn) before it is overwritten due to user
defined memory map. This pfn is used to make sure that user does not try to
read the physical memory beyond saved_max_pfn.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | arch/i386/kernel/setup.c | 12 | ||||
| -rw-r--r-- | include/linux/bootmem.h | 4 | ||||
| -rw-r--r-- | mm/bootmem.c | 8 |
3 files changed, 24 insertions, 0 deletions
diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c index d88ebdf..8d58a05 100644 --- a/arch/i386/kernel/setup.c +++ b/arch/i386/kernel/setup.c @@ -59,6 +59,9 @@ #include "setup_arch_pre.h" #include <bios_ebda.h> +/* Forward Declaration. */ +void __init find_max_pfn(void); + /* This value is set up by the early boot code to point to the value immediately after the boot time page tables. It contains a *physical* address, and must not be in the .bss segment! */ @@ -736,6 +739,15 @@ static void __init parse_cmdline_early (char ** cmdline_p) if (to != command_line) to--; if (!memcmp(from+7, "exactmap", 8)) { +#ifdef CONFIG_CRASH_DUMP + /* If we are doing a crash dump, we + * still need to know the real mem + * size before original memory map is + * reset. + */ + find_max_pfn(); + saved_max_pfn = max_pfn; +#endif from += 8+7; e820.nr_map = 0; userdef = 1; diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h index 500f451..82bd884 100644 --- a/include/linux/bootmem.h +++ b/include/linux/bootmem.h @@ -22,6 +22,10 @@ extern unsigned long min_low_pfn; */ extern unsigned long max_pfn; +#ifdef CONFIG_CRASH_DUMP +extern unsigned long saved_max_pfn; +#endif + /* * node_bootmem_map is a map pointer - the bits represent all physical * memory pages (including holes) on the node. diff --git a/mm/bootmem.c b/mm/bootmem.c index f82f7ae..45275f1 100644 --- a/mm/bootmem.c +++ b/mm/bootmem.c @@ -33,6 +33,14 @@ EXPORT_SYMBOL(max_pfn); /* This is exported so * dma_get_required_mask(), which uses * it, can be an inline function */ +#ifdef CONFIG_CRASH_DUMP +/* + * If we have booted due to a crash, max_pfn will be a very low value. We need + * to know the amount of memory that the previous kernel used. + */ +unsigned long saved_max_pfn; +#endif + /* return the number of _pages_ that will be allocated for the boot bitmap */ unsigned long __init bootmem_bootmap_pages (unsigned long pages) { |
