PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architectures
authorAndrea Righi <righi.andrea@gmail.com>
Thu, 24 Jul 2008 04:28:13 +0000 (21:28 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 24 Jul 2008 17:47:21 +0000 (10:47 -0700)
commit27ac792ca0b0a1e7e65f20342260650516c95864
tree8e0bc93612da0803fe12303ccb75c837cd633c83
parentd92bc318547507a944a22e7ef936793dc0fe167f
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>
57 files changed:
arch/arm/kernel/module.c
arch/arm/plat-omap/fb.c
arch/avr32/mm/ioremap.c
arch/h8300/kernel/setup.c
arch/m68k/amiga/chipram.c
arch/m68knommu/kernel/setup.c
arch/mips/kernel/module.c
arch/mips/sgi-ip27/ip27-klnuma.c
arch/powerpc/kernel/suspend.c
arch/powerpc/lib/code-patching.c
arch/sparc64/kernel/iommu_common.h
arch/x86/kernel/module_64.c
arch/xtensa/kernel/setup.c
drivers/char/random.c
drivers/ieee1394/iso.c
drivers/media/video/pvrusb2/pvrusb2-dvb.c
drivers/media/video/pvrusb2/pvrusb2-ioread.c
drivers/media/video/uvc/uvc_queue.c
drivers/media/video/videobuf-core.c
drivers/mtd/maps/uclinux.c
drivers/net/mlx4/eq.c
drivers/pcmcia/electra_cf.c
drivers/scsi/sun_esp.c
drivers/video/acornfb.c
drivers/video/imxfb.c
drivers/video/omap/dispc.c
drivers/video/omap/omapfb_main.c
drivers/video/pxafb.c
drivers/video/sa1100fb.c
include/asm-alpha/page.h
include/asm-arm/page-nommu.h
include/asm-arm/page.h
include/asm-avr32/page.h
include/asm-blackfin/page.h
include/asm-cris/page.h
include/asm-frv/page.h
include/asm-h8300/page.h
include/asm-ia64/page.h
include/asm-m32r/page.h
include/asm-m68k/dvma.h
include/asm-m68k/page.h
include/asm-m68knommu/page.h
include/asm-mips/page.h
include/asm-mips/processor.h
include/asm-mn10300/page.h
include/asm-parisc/page.h
include/asm-powerpc/page.h
include/asm-s390/page.h
include/asm-sh/page.h
include/asm-sparc/page_32.h
include/asm-sparc/page_64.h
include/asm-um/page.h
include/asm-v850/page.h
include/asm-x86/page.h
include/asm-xtensa/page.h
include/linux/mm.h
sound/core/info.c