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[Xen-devel,for-4.5,v2,7/8] xen: arm: weaken SMP barriers to inner shareable.

Message ID 1392295088-24219-7-git-send-email-ian.campbell@citrix.com
State Superseded
Headers show

Commit Message

Ian Campbell Feb. 13, 2014, 12:38 p.m. UTC
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 principle 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@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
---
 xen/include/asm-arm/system.h |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
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Patch

diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h
index e1f126a..32ed277 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))))