xen: arm: use more specific barriers for read and write barriers.

Note that 32-bit does not provide a load variant of the inner shareable
barrier, so that remains a full any-any barrier.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Tim Deegan <tim@xen.org>

diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h
index 32ed277be7a712e3263858f9ab3bdf5a1dad9fee..7aaaf5016210d30ab7863a61ffa7a289d341a1d3 100644 (file)
--- a/xen/include/asm-arm/system.h
+++ b/xen/include/asm-arm/system.h
@@ -17,12 +17,21 @@
 #define dmb(scope)      asm volatile("dmb " #scope : : : "memory")
 
 #define mb()            dsb(sy)
-#define rmb()           dsb(sy)
-#define wmb()           dsb(sy)
+#ifdef CONFIG_ARM_64
+#define rmb()           dsb(ld)
+#else
+#define rmb()           dsb(sy) /* 32-bit has no ld variant. */
+#endif
+#define wmb()           dsb(st)
 
 #define smp_mb()        dmb(ish)
-#define smp_rmb()       dmb(ish)
-#define smp_wmb()       dmb(ish)
+#ifdef CONFIG_ARM_64
+#define smp_rmb()       dmb(ishld)
+#else
+#define smp_rmb()       dmb(ish) /* 32-bit has no ishld variant. */
+#endif
+
+#define smp_wmb()       dmb(ishst)
 
 #define xchg(ptr,x) \
         ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))