diff options
author | Peter Zijlstra <peterz@infradead.org> | 2016-07-18 18:41:10 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2016-07-20 07:48:40 (GMT) |
commit | 08e237fa56a1d95c1372033bc29c4a2517b3c0fa (patch) | |
tree | 516f04cfcd11fafd8d801c7ce0ed60ca660d26d0 /arch/x86 | |
parent | 4fffe71dd913cca5532da594e2f48a0db6b494dc (diff) | |
download | linux-08e237fa56a1d95c1372033bc29c4a2517b3c0fa.tar.xz |
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')
-rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 2 | ||||
-rw-r--r-- | arch/x86/include/asm/mwait.h | 2 | ||||
-rw-r--r-- | arch/x86/kernel/cpu/intel.c | 5 | ||||
-rw-r--r-- | arch/x86/kernel/process.c | 2 |
4 files changed, 8 insertions, 3 deletions
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index c64b1e9..19ecc6e 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -310,5 +310,5 @@ #endif #define X86_BUG_NULL_SEG X86_BUG(10) /* Nulling a selector preserves the base */ #define X86_BUG_SWAPGS_FENCE X86_BUG(11) /* SWAPGS without input dep on GS */ - +#define X86_BUG_MONITOR X86_BUG(12) /* IPI required to wake up remote CPU */ #endif /* _ASM_X86_CPUFEATURES_H */ diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h index 0deeb2d..f37f2d8 100644 --- a/arch/x86/include/asm/mwait.h +++ b/arch/x86/include/asm/mwait.h @@ -97,7 +97,7 @@ static inline void __sti_mwait(unsigned long eax, unsigned long ecx) */ static inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) { - if (!current_set_polling_and_test()) { + if (static_cpu_has_bug(X86_BUG_MONITOR) || !current_set_polling_and_test()) { if (static_cpu_has_bug(X86_BUG_CLFLUSH_MONITOR)) { mb(); clflush((void *)¤t_thread_info()->flags); diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index c1a89bc..abf6012 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -13,6 +13,7 @@ #include <asm/msr.h> #include <asm/bugs.h> #include <asm/cpu.h> +#include <asm/intel-family.h> #ifdef CONFIG_X86_64 #include <linux/topology.h> @@ -508,6 +509,10 @@ static void init_intel(struct cpuinfo_x86 *c) (c->x86_model == 29 || c->x86_model == 46 || c->x86_model == 47)) set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR); + if (c->x86 == 6 && boot_cpu_has(X86_FEATURE_MWAIT) && + ((c->x86_model == INTEL_FAM6_ATOM_GOLDMONT))) + set_cpu_bug(c, X86_BUG_MONITOR); + #ifdef CONFIG_X86_64 if (c->x86 == 15) c->x86_cache_alignment = c->x86_clflush_size * 2; diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 96becbb..59f68f1 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; |