1
linux/arch/powerpc/lib
Andrea Righi 27ac792ca0 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>
2008-07-24 10:47:21 -07:00
..
alloc.c [POWERPC] Limit range of __init_ref_ok somewhat 2007-10-03 11:48:44 +10:00
checksum_32.S
checksum_64.S
code-patching.c PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architectures 2008-07-24 10:47:21 -07:00
copy_32.S
copypage_64.S
copyuser_64.S
crtsavres.S [POWERPC] Fix -Os kernel builds with newer gcc versions 2008-06-16 15:00:54 +10:00
devres.c [POWERPC] devres: Add devm_ioremap_prot() 2008-05-05 16:47:14 +10:00
div64.S
dma-noncoherent.c powerpc: Prevent memory corruption due to cache invalidation of unaligned DMA buffer 2008-07-01 11:28:54 +10:00
feature-fixups-test.S powerpc: Fixup lwsync at runtime 2008-07-03 16:58:10 +10:00
feature-fixups.c powerpc: Use WARN_ON(1) instead of __WARN() 2008-07-22 10:39:34 +10:00
locks.c
Makefile powerpc: Add self-tests of the feature fixup code 2008-07-01 11:28:30 +10:00
mem_64.S
memcpy_64.S
rheap.c [POWERPC] Make rheap safe for spinlocks 2008-04-17 09:50:38 -05:00
sstep.c
string.S powerpc: Use PPC_LONG and PPC_LONG_ALIGN in lib/string.S 2008-07-22 10:39:35 +10:00
usercopy_64.c