From ecda06289f8202d4c6beb235f59ea464f4a91209 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Sun, 22 Feb 2009 22:14:56 -0800 Subject: [PATCH] x86: check mptable physptr with max_low_pfn on 32bit 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 Signed-off-by: Yinghai Lu Cc: Stefan Reinauer Cc: coreboot@coreboot.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/mpparse.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c index 7f4d258..37cb1bd 100644 --- a/arch/x86/kernel/mpparse.c +++ b/arch/x86/kernel/mpparse.c @@ -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; -- 2.7.4