x86, pat: Fix cacheflush address in change_page_attr_set_clr()

Fix address passed to cpa_flush_range() when changing page
attributes from WB to UC. The address (*addr) is
modified by __change_page_attr_set_clr(). The result is that
the pages being flushed start at the _end_ of the changed range
instead of the beginning.

This should be considered for 2.6.30-stable and 2.6.31-stable.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Stable team <stable@kernel.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 7e600c1962db..e245775ec856 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -822,6 +822,7 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages,
 {
         struct cpa_data cpa;
         int ret, cache, checkalias;
+        unsigned long baddr = 0;
 
         /*
          * Check, if we are requested to change a not supported
@@ -853,6 +854,11 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages,
                          */
                         WARN_ON_ONCE(1);
                 }
+                /*
+                 * Save address for cache flush. *addr is modified in the call
+                 * to __change_page_attr_set_clr() below.
+                 */
+                baddr = *addr;
         }
 
         /* Must avoid aliasing mappings in the highmem code */
@@ -900,7 +906,7 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages,
                         cpa_flush_array(addr, numpages, cache,
                                         cpa.flags, pages);
                 } else
-                        cpa_flush_range(*addr, numpages, cache);
+                        cpa_flush_range(baddr, numpages, cache);
         } else
                 cpa_flush_all(cache);