[Xen-devel] [PATCH v4 6/6] xen: arm: relax barriers when flushing caches

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

We only need an inner shareable barrier here.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
v4: new patch
---
 xen/include/asm-arm/page.h |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index a96e40b..b4d5597 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -263,20 +263,20 @@ extern size_t cacheline_bytes;
 static inline void clean_xen_dcache_va_range(void *p, unsigned long size)
 {
     void *end;
-    dsb(sy);           /* So the CPU issues all writes to the range */
+    dsb(ish);          /* So the CPU issues all writes to the range */
     for ( end = p + size; p < end; p += cacheline_bytes )
         asm volatile (__clean_xen_dcache_one(0) : : "r" (p));
-    dsb(sy);           /* So we know the flushes happen before continuing */
+    dsb(ish);          /* So we know the flushes happen before continuing */
 }
 
 static inline void clean_and_invalidate_xen_dcache_va_range
     (void *p, unsigned long size)
 {
     void *end;
-    dsb(sy);         /* So the CPU issues all writes to the range */
+    dsb(ish);        /* So the CPU issues all writes to the range */
     for ( end = p + size; p < end; p += cacheline_bytes )
         asm volatile (__clean_and_invalidate_xen_dcache_one(0) : : "r" (p));
-    dsb(sy);         /* So we know the flushes happen before continuing */
+    dsb(ish);        /* So we know the flushes happen before continuing */
 }
 
 /* Macros for flushing a single small item.  The predicate is always
@@ -288,9 +288,9 @@ static inline void clean_and_invalidate_xen_dcache_va_range
         clean_xen_dcache_va_range(_p, sizeof(x));                       \
     else                                                                \
         asm volatile (                                                  \
-            "dsb sy;"   /* Finish all earlier writes */                 \
+            "dsb ish;"  /* Finish all earlier writes */                 \
             __clean_xen_dcache_one(0)                                   \
-            "dsb sy;"   /* Finish flush before continuing */            \
+            "dsb ish;"  /* Finish flush before continuing */            \
             : : "r" (_p), "m" (*_p));                                   \
 } while (0)
 
@@ -300,9 +300,9 @@ static inline void clean_and_invalidate_xen_dcache_va_range
         clean_and_invalidate_xen_dcache_va_range(_p, sizeof(x));        \
     else                                                                \
         asm volatile (                                                  \
-            "dsb sy;"   /* Finish all earlier writes */                 \
+            "dsb ish;"   /* Finish all earlier writes */                \
             __clean_and_invalidate_xen_dcache_one(0)                    \
-            "dsb sy;"   /* Finish flush before continuing */            \
+            "dsb ish;"   /* Finish flush before continuing */           \
             : : "r" (_p), "m" (*_p));                                   \
 } while (0)
 
-- 
1.7.10.4


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