[Xen-devel] [PATCH 09/10] xen: arm: weaken SMP barriers to inner shareable.

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

Since all processors are in the inner-shareable domain and we map everything
that way this is sufficient.

The non-SMP barriers remain full system. Although in principal they could
become outer shareable barriers for some hardware this would require us to
know which class a given device is. Given the small number of device drivers
in Xen itself its probably not worth worrying over, although maybe someone
will benchmark at some point.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 xen/include/asm-arm/system.h |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h
index 68efba9..7c3e42d 100644
--- a/xen/include/asm-arm/system.h
+++ b/xen/include/asm-arm/system.h
@@ -20,9 +20,9 @@
 #define rmb()           dsb("sy")
 #define wmb()           dsb("sy")
 
-#define smp_mb()        dmb("sy")
-#define smp_rmb()       dmb("sy")
-#define smp_wmb()       dmb("sy")
+#define smp_mb()        dmb("ish")
+#define smp_rmb()       dmb("ish")
+#define smp_wmb()       dmb("ish")
 
 #define xchg(ptr,x) \
         ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
-- 
1.7.2.5


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