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authorVivek Goyal <vgoyal@in.ibm.com>2005-06-25 14:58:18 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-25 16:24:52 -0700
commit92aa63a5a1bf2e7b0c79e6716d24b76dbbdcf951 (patch)
tree1f4d49c8e9bf02e834e6af8c1f7d4484d9f76c6e /mm
parentd58831e4163699de204dea199be2e903bf5d6eff (diff)
[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>
Diffstat (limited to 'mm')
-rw-r--r--mm/bootmem.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/bootmem.c b/mm/bootmem.c
index f82f7aebbee3..45275f1f8947 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)
{