From 27ac792ca0b0a1e7e65f20342260650516c95864 Mon Sep 17 00:00:00 2001
From: Andrea Righi <righi.andrea@gmail.com>
Date: Wed, 23 Jul 2008 21:28:13 -0700
Subject: PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architectures

On 32-bit architectures PAGE_ALIGN() truncates 64-bit values to the 32-bit
boundary. For example:

	u64 val = PAGE_ALIGN(size);

always returns a value < 4GB even if size is greater than 4GB.

The problem resides in PAGE_MASK definition (from include/asm-x86/page.h for
example):

#define PAGE_SHIFT      12
#define PAGE_SIZE       (_AC(1,UL) << PAGE_SHIFT)
#define PAGE_MASK       (~(PAGE_SIZE-1))
...
#define PAGE_ALIGN(addr)       (((addr)+PAGE_SIZE-1)&PAGE_MASK)

The "~" is performed on a 32-bit value, so everything in "and" with
PAGE_MASK greater than 4GB will be truncated to the 32-bit boundary.
Using the ALIGN() macro seems to be the right way, because it uses
typeof(addr) for the mask.

Also move the PAGE_ALIGN() definitions out of include/asm-*/page.h in
include/linux/mm.h.

See also lkml discussion: http://lkml.org/lkml/2008/6/11/237

[akpm@linux-foundation.org: fix drivers/media/video/uvc/uvc_queue.c]
[akpm@linux-foundation.org: fix v850]
[akpm@linux-foundation.org: fix powerpc]
[akpm@linux-foundation.org: fix arm]
[akpm@linux-foundation.org: fix mips]
[akpm@linux-foundation.org: fix drivers/media/video/pvrusb2/pvrusb2-dvb.c]
[akpm@linux-foundation.org: fix drivers/mtd/maps/uclinux.c]
[akpm@linux-foundation.org: fix powerpc]
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/video/omap/dispc.c       | 1 +
 drivers/video/omap/omapfb_main.c | 1 +
 2 files changed, 2 insertions(+)

(limited to 'drivers/video/omap')

diff --git a/drivers/video/omap/dispc.c b/drivers/video/omap/dispc.c
index ab32ceb0617..ab77c51fe9d 100644
--- a/drivers/video/omap/dispc.c
+++ b/drivers/video/omap/dispc.c
@@ -20,6 +20,7 @@
  */
 #include <linux/kernel.h>
 #include <linux/dma-mapping.h>
+#include <linux/mm.h>
 #include <linux/vmalloc.h>
 #include <linux/clk.h>
 #include <linux/io.h>
diff --git a/drivers/video/omap/omapfb_main.c b/drivers/video/omap/omapfb_main.c
index 14d0f7a1114..f85af5c4fa6 100644
--- a/drivers/video/omap/omapfb_main.c
+++ b/drivers/video/omap/omapfb_main.c
@@ -25,6 +25,7 @@
  * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 #include <linux/platform_device.h>
+#include <linux/mm.h>
 #include <linux/uaccess.h>
 
 #include <asm/mach-types.h>
-- 
cgit v1.2.3