Add a membar to libgc's UNLOCK () on arm. Fixes #683409.

diff --git a/include/private/gc_locks.h b/include/private/gc_locks.h
index df8736d3d4e0cc5430526798bbcf7b4322a5ed4d..a45553aa7ca9e249d201c0b719ae444e6c4364bf 100644 (file)
--- a/include/private/gc_locks.h
+++ b/include/private/gc_locks.h
@@ -250,6 +250,14 @@
 #endif
         }
 #       define GC_TEST_AND_SET_DEFINED
+      inline static void GC_clear(volatile unsigned int *addr) {
+#ifdef HAVE_ARMV6
+                 /* Memory barrier */
+                 __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" : : "r" (0) : "memory");
+#endif
+                 *(addr) = 0;
+      }
+#     define GC_CLEAR_DEFINED
 #    endif /* ARM32 */
 #    ifdef CRIS
         inline static int GC_test_and_set(volatile unsigned int *addr) {