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x86: check mptable physptr with max_low_pfn on 32bit

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Impact: fix early crash on LinuxBIOS systems

Kevin O'Connor reported that Coreboot aka LinuxBIOS tries to put
mptable somewhere very high, well above max_low_pfn (below which
BIOSes generally put the mptable), causing a panic.

The BIOS will probably be changed to be compatible with older
Linus versions, but nevertheless the MP-spec does not forbid
an MP-table in arbitrary system RAM, so make sure it all
works even if the table is in an unexpected place.

Check physptr with max_low_pfn * PAGE_SIZE.

Reported-by: Kevin O'Connor <kevin@koconnor.net>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Stefan Reinauer <stepan@coresystems.de>
Cc: coreboot@coreboot.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Yinghai Lu 2009-02-22 22:14:56 -08:00 committed by Ingo Molnar
parent 8e6dafd6c7
commit ecda06289f
1 changed files with 12 additions and 3 deletions
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15
arch/x86/kernel/mpparse.c
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@ -710,13 +710,22 @@ static int __init smp_scan_config(unsigned long base, unsigned long length,
* of physical memory; so that simply reserving
* PAGE_SIZE from mpf->physptr yields BUG()
* in reserve_bootmem.
* also need to make sure physptr is below than
* max_low_pfn
* we don't need reserve the area above max_low_pfn
*/
unsigned long end = max_low_pfn * PAGE_SIZE;
if (mpf->physptr + size > end)
size = end - mpf->physptr;
#endif
if (mpf->physptr < end) {
if (mpf->physptr + size > end)
size = end - mpf->physptr;
reserve_bootmem_generic(mpf->physptr, size,
BOOTMEM_DEFAULT);
}
#else
reserve_bootmem_generic(mpf->physptr, size,
BOOTMEM_DEFAULT);
#endif
}
return 1;