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authorPeter Zijlstra <peterz@infradead.org>2016-07-18 11:41:10 -0700
committerIngo Molnar <mingo@kernel.org>2016-07-20 09:48:40 +0200
commit08e237fa56a1d95c1372033bc29c4a2517b3c0fa (patch)
tree516f04cfcd11fafd8d801c7ce0ed60ca660d26d0 /arch/x86/kernel/process.c
parent4fffe71dd913cca5532da594e2f48a0db6b494dc (diff)
downloadlinux-08e237fa56a1d95c1372033bc29c4a2517b3c0fa.tar.bz2
x86/cpu: Add workaround for MONITOR instruction erratum on Goldmont based CPUs
Monitored cached line may not wake up from mwait on certain Goldmont based CPUs. This patch will avoid calling current_set_polling_and_test() and thereby not set the TIF_ flag. The result is that we'll always send IPIs for wakeups. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1468867270-18493-1-git-send-email-jacob.jun.pan@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/process.c')
-rw-r--r--arch/x86/kernel/process.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 96becbbb52e0..59f68f1d734b 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -404,7 +404,7 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
if (c->x86_vendor != X86_VENDOR_INTEL)
return 0;
- if (!cpu_has(c, X86_FEATURE_MWAIT))
+ if (!cpu_has(c, X86_FEATURE_MWAIT) || static_cpu_has_bug(X86_BUG_MONITOR))
return 0;
return 1;