Upadte.

2000-04-11  Ulrich Drepper  <drepper@redhat.com>

	* internals.h: Define MEMORY_BARRIER as empty if not defined already.
	* spinlock.c (__pthread_lock): Add memory barriers.
	(__pthread_unlock): Likewise.
	* sysdeps/alpha/pt-machine.h (MEMORY_BARRIER): Define using mb
	instruction.
	(RELEASE): Not needed anymore.
	(__compare_and_swap): Mark asm as modifying memory.
	* sysdeps/powerpc/pt-machine.h (sync): Remove.  Replace with definition
	of MEMORY_BARRIER.
	(__compare_and_swap): Use MEMORY_BARRIER instead of sync.
	* sysdeps/sparc/sparc32/pt-machine.h (RELEASE): Not needed anymore.
	(MEMORY_BARRIER): Define using stbar.
	* sysdeps/sparc/sparc64/pt-machine.h (MEMORY_BARRIER): Define using
	stbar.
	(__compare_and_swap): Use MEMORY_BARRIER to ensure ordering.
	Patch by Xavier Leroy <Xavier.Leroy@inria.fr> based on comments by
	Mike Burrows <m3b@pa.dec.com>.

2 files changed, 9 insertions, 4 deletions

diff --git a/linuxthreads/sysdeps/sparc/sparc32/pt-machine.h b/linuxthreads/sysdeps/sparc/sparc32/pt-machine.h
index 69af8579aa..ddf4932af9 100644
--- a/linuxthreads/sysdeps/sparc/sparc32/pt-machine.h
+++ b/linuxthreads/sysdeps/sparc/sparc32/pt-machine.h
@@ -37,9 +37,8 @@ testandset (int *spinlock)
 }
 
 
-/* Spinlock release; default is just set to zero.  */
-#define RELEASE(spinlock) \
-  __asm__ __volatile__("stbar; stb %1,%0" : "=m"(*(spinlock)) : "r"(0));
+/* Memory barrier; default is to do nothing */
+#define MEMORY_BARRIER() __asm__ __volatile__("stbar" : : : "memory")
 
 
 /* Get some notion of the current stack.  Need not be exactly the top
diff --git a/linuxthreads/sysdeps/sparc/sparc64/pt-machine.h b/linuxthreads/sysdeps/sparc/sparc64/pt-machine.h
index 5560003fc8..02167bd601 100644
--- a/linuxthreads/sysdeps/sparc/sparc64/pt-machine.h
+++ b/linuxthreads/sysdeps/sparc/sparc64/pt-machine.h
@@ -37,6 +37,12 @@ testandset (int *spinlock)
 }
 
 
+/* Memory barrier; default is to do nothing */
+/* FIXME: is stbar OK, or should we use the more general membar instruction?
+   If so, which mode to pass to membar? */
+#define MEMORY_BARRIER() __asm__ __volatile__("stbar" : : : "memory")
+
+
 /* Get some notion of the current stack.  Need not be exactly the top
    of the stack, just something somewhere in the current frame.  */
 #define CURRENT_STACK_FRAME  stack_pointer
@@ -66,7 +72,7 @@ __compare_and_swap (long int *p, long int oldval, long int newval)
   __asm__ __volatile__ ("casx	[%4], %2, %0"
 			: "=r"(readval), "=m"(*p)
 			: "r"(oldval), "m"(*p), "r"(p), "0"(newval));
-
+  MEMORY_BARRIER();
   return readval == oldval;
 }