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| author | Andrea Righi <righi.andrea@gmail.com> | 2008-07-23 21:28:13 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-24 10:47:21 -0700 |
| commit | 27ac792ca0b0a1e7e65f20342260650516c95864 (patch) | |
| tree | 8e0bc93612da0803fe12303ccb75c837cd633c83 /include/asm-sparc | |
| parent | d92bc318547507a944a22e7ef936793dc0fe167f (diff) | |
| download | op-kernel-dev-27ac792ca0b0a1e7e65f20342260650516c95864.zip op-kernel-dev-27ac792ca0b0a1e7e65f20342260650516c95864.tar.gz | |
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>
Diffstat (limited to 'include/asm-sparc')
| -rw-r--r-- | include/asm-sparc/page_32.h | 3 | ||||
| -rw-r--r-- | include/asm-sparc/page_64.h | 3 |
2 files changed, 0 insertions, 6 deletions
diff --git a/include/asm-sparc/page_32.h b/include/asm-sparc/page_32.h index 14de518..cf5fb70 100644 --- a/include/asm-sparc/page_32.h +++ b/include/asm-sparc/page_32.h @@ -134,9 +134,6 @@ BTFIXUPDEF_SETHI(sparc_unmapped_base) #endif /* !(__ASSEMBLY__) */ -/* to align the pointer to the (next) page boundary */ -#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK) - #define PAGE_OFFSET 0xf0000000 #ifndef __ASSEMBLY__ extern unsigned long phys_base; diff --git a/include/asm-sparc/page_64.h b/include/asm-sparc/page_64.h index a8a2bba..b579b91 100644 --- a/include/asm-sparc/page_64.h +++ b/include/asm-sparc/page_64.h @@ -106,9 +106,6 @@ typedef struct page *pgtable_t; #endif /* !(__ASSEMBLY__) */ -/* to align the pointer to the (next) page boundary */ -#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK) - /* We used to stick this into a hard-coded global register (%g4) * but that does not make sense anymore. */ |
