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authorDavidlohr Bueso <dave@stgolabs.net>2016-04-06 08:05:15 (GMT)
committerIngo Molnar <mingo@kernel.org>2016-04-13 08:54:23 (GMT)
commitbf92b1feb658f6a262daf3a87d790997a1dca0ff (patch)
tree46bae68fb5d0303a87d4982879fae9cbc637b5c0 /arch/x86/kernel/cpu
parent69385f8879344f4a1f078f761bd3523fcf697131 (diff)
downloadlinux-bf92b1feb658f6a262daf3a87d790997a1dca0ff.tar.xz
x86/mce: Remove explicit smp_rmb() when starting CPUs sync
mce_start() has an explicit smp_wmb() to serialize writes to global_nwo and mce_callin. However, atomic_inc_return() implies barriers on both sides of the call, as such simply rely on this full SMP barrier. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/1458602396-840-1-git-send-email-dave@stgolabs.net Link: http://lkml.kernel.org/r/1459929916-12852-3-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/cpu')
-rw-r--r--arch/x86/kernel/cpu/mcheck/mce.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index f0c921b..6b7039c 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -830,9 +830,9 @@ static int mce_start(int *no_way_out)
atomic_add(*no_way_out, &global_nwo);
/*
- * global_nwo should be updated before mce_callin
+ * Rely on the implied barrier below, such that global_nwo
+ * is updated before mce_callin.
*/
- smp_wmb();
order = atomic_inc_return(&mce_callin);
/*