linux-atomic.c (SYNC_LOCK_RELEASE): Place memory barrier before the lock release.

* arm/linux-atomic.c (SYNC_LOCK_RELEASE): Place memory barrier before the lock release. From-SVN: r154949

linux-atomic.c (SYNC_LOCK_RELEASE): Place memory barrier before the lock release.
* arm/linux-atomic.c (SYNC_LOCK_RELEASE): Place memory barrier before the lock release. From-SVN: r154949
cf9eb565 · Richard Earnshaw · Richard Earnshaw · bcaf576b · cf9eb565 · cf9eb565
Commit cf9eb565 authored Dec 03, 2009 by Richard Earnshaw Committed by Richard Earnshaw Dec 03, 2009
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gcc/ChangeLog
+5 -0

gcc/config/arm/linux-atomic.c
+3 -1

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--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
+2009-12-03  Richard Earnshaw  <rearnsha@arm.com>
+
+	* arm/linux-atomic.c (SYNC_LOCK_RELEASE): Place memory barrier
+	before the lock release.
+
 2009-12-03  Michael Matz  <matz@suse.de>

 	PR middle-end/38474
--- a/gcc/config/arm/linux-atomic.c
+++ b/gcc/config/arm/linux-atomic.c
@@ -266,8 +266,10 @@ SUBWORD_TEST_AND_SET (char,  1)
  void HIDDEN								\
  __sync_lock_release_##WIDTH (TYPE *ptr)				\
  {									\
-    *ptr = 0;								\
+    /* All writes before this point must be seen before we release	\
+       the lock itself.  */						\
    __kernel_dmb ();							\
+    *ptr = 0;								\
  }

 SYNC_LOCK_RELEASE (int,   4)