1 files changed, 39 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));
+}