--- Begin Message ---
- Subject: No Subject
- From:
- Date: Mon, 28 Mar 2005 17:39:11 +0530
From: "Vivek Goyal" <[email protected]>
o 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 <[email protected]>
---
linux-2.6.12-rc1-mm1-1M-root/arch/i386/kernel/setup.c | 12 ++++++++++++
linux-2.6.12-rc1-mm1-1M-root/include/linux/bootmem.h | 4 ++++
linux-2.6.12-rc1-mm1-1M-root/mm/bootmem.c | 8 ++++++++
3 files changed, 24 insertions(+)
diff -puN arch/i386/kernel/setup.c~crashdump-x86-retrieve-max-pfn arch/i386/kernel/setup.c
--- linux-2.6.12-rc1-mm1-1M/arch/i386/kernel/setup.c~crashdump-x86-retrieve-max-pfn 2005-03-22 15:47:33.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/arch/i386/kernel/setup.c 2005-03-22 15:47:33.000000000 +0530
@@ -57,6 +57,9 @@
#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! */
@@ -715,6 +718,15 @@ static void __init parse_cmdline_early (
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 -puN include/linux/bootmem.h~crashdump-x86-retrieve-max-pfn include/linux/bootmem.h
--- linux-2.6.12-rc1-mm1-1M/include/linux/bootmem.h~crashdump-x86-retrieve-max-pfn 2005-03-22 15:47:33.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/include/linux/bootmem.h 2005-03-22 15:47:33.000000000 +0530
@@ -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 -puN mm/bootmem.c~crashdump-x86-retrieve-max-pfn mm/bootmem.c
--- linux-2.6.12-rc1-mm1-1M/mm/bootmem.c~crashdump-x86-retrieve-max-pfn 2005-03-22 15:47:33.000000000 +0530
+++ linux-2.6.12-rc1-mm1-1M-root/mm/bootmem.c 2005-03-22 15:47:33.000000000 +0530
@@ -33,6 +33,14 @@ EXPORT_SYMBOL(max_pfn); /* This is expo
* 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)
{
_
--- End Message ---
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
