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x86: fix the missing BIOS area check in page_is_ram

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page_is_ram has a FIXME since ages, which reminds to sanity check the
BIOS area between 640k and 1M, which is sometimes falsely reported as
RAM in the e820 tables.

Implement the sanity check. Move the BIOS range defines from
pageattr.c into e820.h to avoid duplicate defines.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Thomas Gleixner 2008-01-30 13:34:06 +01:00 committed by Ingo Molnar
parent 5f5192b9fe
commit 950f9d95be
3 changed files with 14 additions and 11 deletions
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15
arch/x86/mm/ioremap.c
View file

@ -42,13 +42,18 @@ int page_is_ram(unsigned long pagenr)
*/
if (e820.map[i].type != E820_RAM)
continue;
/*
* !!!FIXME!!! Some BIOSen report areas as RAM that
* are not. Notably the 640->1Mb area. We need a sanity
* check here.
*/
addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
/*
* Sanity check: Some BIOSen report areas as RAM that
* are not. Notably the 640->1Mb area, which is the
* PCI BIOS area.
*/
if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
end < (BIOS_END >> PAGE_SHIFT))
continue;
if ((pagenr >= addr) && (pagenr < end))
return 1;
}

7
arch/x86/mm/pageattr.c
View file

@ -9,18 +9,13 @@
#include <linux/slab.h>
#include <linux/mm.h>
#include <asm/e820.h>
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
/*
* We must allow the BIOS range to be executable:
*/
#define BIOS_BEGIN 0x000a0000
#define BIOS_END 0x00100000
static inline int
within(unsigned long addr, unsigned long start, unsigned long end)
{

3
include/asm-x86/e820.h
View file

@ -25,6 +25,9 @@ struct e820map {
#define ISA_START_ADDRESS 0xa0000
#define ISA_END_ADDRESS 0x100000
#define BIOS_BEGIN 0x000a0000
#define BIOS_END 0x00100000
#ifdef __KERNEL__
#ifdef CONFIG_X86_32
# include "e820_32.h"