[Xen-changelog] [xen stable-4.8] xen/arm: fix affected memory range by dcache clean functions

[patchbot@xxxxxxx]

commit 2e68fda962226d4de916d5ceab9d9d6037d94d45
Author:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
AuthorDate: Thu Mar 2 17:15:26 2017 -0800
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Tue Mar 7 11:23:43 2017 -0800

    xen/arm: fix affected memory range by dcache clean functions
    
    clean_dcache_va_range and clean_and_invalidate_dcache_va_range don't
    calculate the range correctly when "end" is not cacheline aligned. As a
    result, the last cacheline is not skipped. Fix the issue by aligning the
    start address to the cacheline size.
    
    In addition, make the code simpler and faster in
    invalidate_dcache_va_range, by removing the module operation and using
    bitmasks instead. Also remove the size adjustments in
    invalidate_dcache_va_range, because the size variable is not used later
    on.
    
    Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xxxxxxxxxx>
    Reviewed-by: Julien Grall <julien.grall@xxxxxxx>
    Tested-by: Edgar E. Iglesias <edgar.iglesias@xxxxxxxxxx>
---
 xen/include/asm-arm/page.h | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index c492d6d..a0f9344 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -292,24 +292,20 @@ extern size_t cacheline_bytes;
 
 static inline int invalidate_dcache_va_range(const void *p, unsigned long size)
 {
-    size_t off;
     const void *end = p + size;
+    size_t cacheline_mask = cacheline_bytes - 1;
 
     dsb(sy);           /* So the CPU issues all writes to the range */
 
-    off = (unsigned long)p % cacheline_bytes;
-    if ( off )
+    if ( (uintptr_t)p & cacheline_mask )
     {
-        p -= off;
+        p = (void *)((uintptr_t)p & ~cacheline_mask);
         asm volatile (__clean_and_invalidate_dcache_one(0) : : "r" (p));
         p += cacheline_bytes;
-        size -= cacheline_bytes - off;
     }
-    off = (unsigned long)end % cacheline_bytes;
-    if ( off )
+    if ( (uintptr_t)end & cacheline_mask )
     {
-        end -= off;
-        size -= off;
+        end = (void *)((uintptr_t)end & ~cacheline_mask);
         asm volatile (__clean_and_invalidate_dcache_one(0) : : "r" (end));
     }
 
@@ -323,9 +319,10 @@ static inline int invalidate_dcache_va_range(const void 
*p, unsigned long size)
 
 static inline int clean_dcache_va_range(const void *p, unsigned long size)
 {
-    const void *end;
+    const void *end = p + size;
     dsb(sy);           /* So the CPU issues all writes to the range */
-    for ( end = p + size; p < end; p += cacheline_bytes )
+    p = (void *)((uintptr_t)p & ~(cacheline_bytes - 1));
+    for ( ; p < end; p += cacheline_bytes )
         asm volatile (__clean_dcache_one(0) : : "r" (p));
     dsb(sy);           /* So we know the flushes happen before continuing */
     /* ARM callers assume that dcache_* functions cannot fail. */
@@ -335,9 +332,10 @@ static inline int clean_dcache_va_range(const void *p, 
unsigned long size)
 static inline int clean_and_invalidate_dcache_va_range
     (const void *p, unsigned long size)
 {
-    const void *end;
+    const void *end = p + size;
     dsb(sy);         /* So the CPU issues all writes to the range */
-    for ( end = p + size; p < end; p += cacheline_bytes )
+    p = (void *)((uintptr_t)p & ~(cacheline_bytes - 1));
+    for ( ; p < end; p += cacheline_bytes )
         asm volatile (__clean_and_invalidate_dcache_one(0) : : "r" (p));
     dsb(sy);         /* So we know the flushes happen before continuing */
     /* ARM callers assume that dcache_* functions cannot fail. */
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.8

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