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-rw-r--r--sysdeps/powerpc/powerpc32/bits/atomic.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/bits/atomic.h b/sysdeps/powerpc/powerpc32/bits/atomic.h
index 0f1a72335f..6fcc669fb1 100644
--- a/sysdeps/powerpc/powerpc32/bits/atomic.h
+++ b/sysdeps/powerpc/powerpc32/bits/atomic.h
@@ -89,12 +89,27 @@
# define __arch_atomic_decrement_if_positive_64(mem) \
({ abort (); (*mem)--; })
+#ifdef _ARCH_PWR4
+/*
+ * Newer powerpc64 processors support the new "light weight" sync (lwsync)
+ * So if the build is using -mcpu=[power4,power5,power5+,970] we can
+ * safely use lwsync.
+ */
+# define atomic_read_barrier() __asm ("lwsync" ::: "memory")
+/*
+ * "light weight" sync can also be used for the release barrier.
+ */
+# ifndef UP
+# define __ARCH_REL_INSTR "lwsync"
+# endif
+#else
/*
* Older powerpc32 processors don't support the new "light weight"
* sync (lwsync). So the only safe option is to use normal sync
* for all powerpc32 applications.
*/
# define atomic_read_barrier() __asm ("sync" ::: "memory")
+#endif
/*
* Include the rest of the atomic ops macros which are common to both