X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=include%2Furcu%2Farch%2Farm.h;h=54ca4fabc79de65bad94009c177e73a88b37b481;hp=5cbca7d7f1d0d523186b40837ce93ff515615128;hb=9260f372503da28b709498280ebca39f4331d1e1;hpb=6893800a4d1cc14dff0395ddcd660a5138db183d

diff --git a/include/urcu/arch/arm.h b/include/urcu/arch/arm.h
index 5cbca7d..54ca4fa 100644
--- a/include/urcu/arch/arm.h
+++ b/include/urcu/arch/arm.h
@@ -30,11 +30,30 @@
 extern "C" {
 #endif
 
-#ifdef CONFIG_RCU_ARM_HAVE_DMB
-#define cmm_mb()	__asm__ __volatile__ ("dmb":::"memory")
-#define cmm_rmb()	__asm__ __volatile__ ("dmb":::"memory")
-#define cmm_wmb()	__asm__ __volatile__ ("dmb":::"memory")
-#endif /* CONFIG_RCU_ARM_HAVE_DMB */
+/*
+ * Using DMB is faster than the builtin __sync_synchronize and this instruction is
+ * part of the baseline ARMv7 ISA.
+ */
+#ifdef URCU_ARCH_ARMV7
+
+/* For backwards compat. */
+#define CONFIG_RCU_ARM_HAVE_DMB 1
+
+/*
+ * Issues full system DMB operation.
+ */
+#define cmm_mb()	__asm__ __volatile__ ("dmb sy":::"memory")
+#define cmm_rmb()	__asm__ __volatile__ ("dmb sy":::"memory")
+#define cmm_wmb()	__asm__ __volatile__ ("dmb sy":::"memory")
+
+/*
+ * Issues DMB operation only to the inner shareable domain.
+ */
+#define cmm_smp_mb()	__asm__ __volatile__ ("dmb ish":::"memory")
+#define cmm_smp_rmb()	__asm__ __volatile__ ("dmb ish":::"memory")
+#define cmm_smp_wmb()	__asm__ __volatile__ ("dmb ish":::"memory")
+
+#endif /* URCU_ARCH_ARMV7 */
 
 #include <stdlib.h>
 #include <sys/time.h>
@@ -47,6 +66,28 @@ extern "C" {
 #define __NR_membarrier		389
 #endif
 
+/*
+ * Error out for compilers with known bugs.
+ */
+
+/*
+ * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58854
+ */
+#ifdef URCU_GCC_VERSION
+# if URCU_GCC_VERSION >= 40800 && URCU_GCC_VERSION <= 40802
+#  error Your gcc version produces clobbered frame accesses
+# endif
+#endif
+
+/*
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42263
+ */
+#ifdef URCU_GCC_VERSION
+# if URCU_GCC_VERSION >= 40400 && URCU_GCC_VERSION <= 40402
+#  error Your gcc version has a non-functional __sync_synchronize()
+# endif
+#endif
+
 #ifdef __cplusplus
 }
 #endif