2 files changed, 49 insertions, 0 deletions

diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 628348c9f6c5..9df507d36e0b 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -202,3 +202,42 @@ void flush_dcache_page(struct page *page)
         }
 }
 EXPORT_SYMBOL(flush_dcache_page);
+
+/*
+ * Flush an anonymous page so that users of get_user_pages()
+ * can safely access the data.  The expected sequence is:
+ *
+ *  get_user_pages()
+ *    -> flush_anon_page
+ *  memcpy() to/from page
+ *  if written to page, flush_dcache_page()
+ */
+void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
+{
+        unsigned long pfn;
+
+        /* VIPT non-aliasing caches need do nothing */
+        if (cache_is_vipt_nonaliasing())
+                return;
+
+        /*
+         * Write back and invalidate userspace mapping.
+         */
+        pfn = page_to_pfn(page);
+        if (cache_is_vivt()) {
+                flush_cache_page(vma, vmaddr, pfn);
+        } else {
+                /*
+                 * For aliasing VIPT, we can flush an alias of the
+                 * userspace address only.
+                 */
+                flush_pfn_alias(pfn, vmaddr);
+        }
+
+        /*
+         * Invalidate kernel mapping.  No data should be contained
+         * in this mapping of the page.  FIXME: this is overkill
+         * since we actually ask for a write-back and invalidate.
+         */
+        __cpuc_flush_dcache_page(page_address(page));
+}
diff --git a/include/asm-arm/cacheflush.h b/include/asm-arm/cacheflush.h
index d51049522cd0..5f531ea03059 100644
--- a/include/asm-arm/cacheflush.h
+++ b/include/asm-arm/cacheflush.h
@@ -357,6 +357,16 @@ extern void flush_dcache_page(struct page *);
 
 extern void __flush_dcache_page(struct address_space *mapping, struct page *page);
 
+#define ARCH_HAS_FLUSH_ANON_PAGE
+static inline void flush_anon_page(struct vm_area_struct *vma,
+                         struct page *page, unsigned long vmaddr)
+{
+        extern void __flush_anon_page(struct vm_area_struct *vma,
+                                struct page *, unsigned long);
+        if (PageAnon(page))
+                __flush_anon_page(vma, page, vmaddr);
+}
+
 #define flush_dcache_mmap_lock(mapping) \
         write_lock_irq(&(mapping)->tree_lock)
 #define flush_dcache_mmap_unlock(mapping) \