Commit-ID: 8dbf4a30033ff61091015f0076e872b5c8f717cc Gitweb: http://git.kernel.org/tip/8dbf4a30033ff61091015f0076e872b5c8f717cc Author: Ajaykumar Hotchandani <ajaykumar.hotchandani@xxxxxxxxxx> AuthorDate: Fri, 11 Nov 2011 18:31:57 +0530 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Mon, 5 Dec 2011 15:06:15 +0100 x86/mtrr: Resolve inconsistency with Intel processor manual Following is from Notes of section 11.5.3 of Intel processor manual available at: http://www.intel.com/Assets/PDF/manual/325384.pdf For the Pentium 4 and Intel Xeon processors, after the sequence of steps given above has been executed, the cache lines containing the code between the end of the WBINVD instruction and before the MTRRS have actually been disabled may be retained in the cache hierarchy. Here, to remove code from the cache completely, a second WBINVD instruction must be executed after the MTRRs have been disabled. This patch provides resolution for that. Ideally, I will like to make changes only for Pentium 4 and Xeon processors. But, I am not finding easier way to do it. And, extra wbinvd() instruction does not hurt much for other processors. Signed-off-by: Ajaykumar Hotchandani <ajaykumar.hotchandani@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/4EBD1CC5.3030008@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- arch/x86/kernel/cpu/mtrr/generic.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index e1fe7f4..97b2635 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -694,6 +694,7 @@ static void prepare_set(void) __acquires(set_atomicity_lock) /* Disable MTRRs, and set the default type to uncached */ mtrr_wrmsr(MSR_MTRRdefType, deftype_lo & ~0xcff, deftype_hi); + wbinvd(); } static void post_set(void) __releases(set_atomicity_lock) -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html