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authorPeter Zijlstra <peterz@infradead.org>2014-03-13 19:00:35 +0100
committerIngo Molnar <mingo@kernel.org>2014-04-18 14:20:46 +0200
commitd00a569284b1340c16fe2c148099e077ea09ebc9 (patch)
tree5e44a663929cdd1288989150ca9a7304a29cabd9
parentce3609f93445846f7b5a5b4bacb236a9bdc35216 (diff)
arch,x86: Convert smp_mb__*()
x86 is strongly ordered and all its atomic ops imply a full barrier. Implement the two new primitives as the old ones were. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/n/tip-knswsr5mldkr0w1lrdxvc81w@git.kernel.org Cc: Dave Jones <davej@redhat.com> Cc: Jesse Brandeburg <jesse.brandeburg@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michel Lespinasse <walken@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/include/asm/atomic.h7
-rw-r--r--arch/x86/include/asm/barrier.h4
-rw-r--r--arch/x86/include/asm/bitops.h6
-rw-r--r--arch/x86/include/asm/sync_bitops.h2
-rw-r--r--arch/x86/kernel/apic/hw_nmi.c2
5 files changed, 9 insertions, 12 deletions
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index b17f4f48ecd..6dd1c7dd047 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -7,6 +7,7 @@
#include <asm/alternative.h>
#include <asm/cmpxchg.h>
#include <asm/rmwcc.h>
+#include <asm/barrier.h>
/*
* Atomic operations that C can't guarantee us. Useful for
@@ -243,12 +244,6 @@ static inline void atomic_or_long(unsigned long *v1, unsigned long v2)
: : "r" ((unsigned)(mask)), "m" (*(addr)) \
: "memory")
-/* Atomic operations are already serializing on x86 */
-#define smp_mb__before_atomic_dec() barrier()
-#define smp_mb__after_atomic_dec() barrier()
-#define smp_mb__before_atomic_inc() barrier()
-#define smp_mb__after_atomic_inc() barrier()
-
#ifdef CONFIG_X86_32
# include <asm/atomic64_32.h>
#else
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 69bbb484502..5c7198cca5e 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -137,6 +137,10 @@ do { \
#endif
+/* Atomic operations are already serializing on x86 */
+#define smp_mb__before_atomic() barrier()
+#define smp_mb__after_atomic() barrier()
+
/*
* Stop RDTSC speculation. This is needed when you need to use RDTSC
* (or get_cycles or vread that possibly accesses the TSC) in a defined
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 9fc1af74dc8..afcd35d331d 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -15,6 +15,7 @@
#include <linux/compiler.h>
#include <asm/alternative.h>
#include <asm/rmwcc.h>
+#include <asm/barrier.h>
#if BITS_PER_LONG == 32
# define _BITOPS_LONG_SHIFT 5
@@ -102,7 +103,7 @@ static inline void __set_bit(long nr, volatile unsigned long *addr)
*
* clear_bit() is atomic and may not be reordered. However, it does
* not contain a memory barrier, so if it is used for locking purposes,
- * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
+ * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic()
* in order to ensure changes are visible on other processors.
*/
static __always_inline void
@@ -156,9 +157,6 @@ static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
__clear_bit(nr, addr);
}
-#define smp_mb__before_clear_bit() barrier()
-#define smp_mb__after_clear_bit() barrier()
-
/**
* __change_bit - Toggle a bit in memory
* @nr: the bit to change
diff --git a/arch/x86/include/asm/sync_bitops.h b/arch/x86/include/asm/sync_bitops.h
index 05af3b31d52..f28a24b51dc 100644
--- a/arch/x86/include/asm/sync_bitops.h
+++ b/arch/x86/include/asm/sync_bitops.h
@@ -41,7 +41,7 @@ static inline void sync_set_bit(long nr, volatile unsigned long *addr)
*
* sync_clear_bit() is atomic and may not be reordered. However, it does
* not contain a memory barrier, so if it is used for locking purposes,
- * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
+ * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic()
* in order to ensure changes are visible on other processors.
*/
static inline void sync_clear_bit(long nr, volatile unsigned long *addr)
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index a698d7165c9..eab67047dec 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -57,7 +57,7 @@ void arch_trigger_all_cpu_backtrace(void)
}
clear_bit(0, &backtrace_flag);
- smp_mb__after_clear_bit();
+ smp_mb__after_atomic();
}
static int __kprobes