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x86: fix page_is_ram() thinko

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page_is_ram() has a special case for the 640k-1M bios area, however
due to a thinko the special case checks the e820 table entry and
not the memory the user has asked for. This patch fixes the bug.

[ mingo@elte.hu: this too is better solved in the e820 space, but those
  fixes are too intrusive for v2.6.25. ]

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Arjan van de Ven 2008-02-18 09:58:45 -08:00 committed by Ingo Molnar
parent d8a9e6a51e
commit 156fbc3fbe
1 changed files with 7 additions and 8 deletions
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15
arch/x86/mm/ioremap.c
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@ -50,6 +50,13 @@ int page_is_ram(unsigned long pagenr)
if (pagenr == 0)
return 0;
/*
* Second special case: Some BIOSen report the PC BIOS
* area (640->1Mb) as ram even though it is not.
*/
if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
pagenr < (BIOS_END >> PAGE_SHIFT))
return 0;
for (i = 0; i < e820.nr_map; i++) {
/*
@ -60,14 +67,6 @@ int page_is_ram(unsigned long pagenr)
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;