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authorAndrea Righi <righi.andrea@gmail.com>2008-07-24 00:28:13 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 13:47:21 -0400
commit27ac792ca0b0a1e7e65f20342260650516c95864 (patch)
tree8e0bc93612da0803fe12303ccb75c837cd633c83 /arch/sparc64/kernel
parentd92bc318547507a944a22e7ef936793dc0fe167f (diff)
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 'arch/sparc64/kernel')
-rw-r--r--arch/sparc64/kernel/iommu_common.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/sparc64/kernel/iommu_common.h b/arch/sparc64/kernel/iommu_common.h
index f3575a614fa2..53b19c8231a9 100644
--- a/arch/sparc64/kernel/iommu_common.h
+++ b/arch/sparc64/kernel/iommu_common.h
@@ -23,7 +23,7 @@
23#define IO_PAGE_SHIFT 13 23#define IO_PAGE_SHIFT 13
24#define IO_PAGE_SIZE (1UL << IO_PAGE_SHIFT) 24#define IO_PAGE_SIZE (1UL << IO_PAGE_SHIFT)
25#define IO_PAGE_MASK (~(IO_PAGE_SIZE-1)) 25#define IO_PAGE_MASK (~(IO_PAGE_SIZE-1))
26#define IO_PAGE_ALIGN(addr) (((addr)+IO_PAGE_SIZE-1)&IO_PAGE_MASK) 26#define IO_PAGE_ALIGN(addr) ALIGN(addr, IO_PAGE_SIZE)
27 27
28#define IO_TSB_ENTRIES (128*1024) 28#define IO_TSB_ENTRIES (128*1024)
29#define IO_TSB_SIZE (IO_TSB_ENTRIES * 8) 29#define IO_TSB_SIZE (IO_TSB_ENTRIES * 8)