linux/include/asm-avr32/page.h
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

105 lines
3.1 KiB
C

/*
* Copyright (C) 2004-2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __ASM_AVR32_PAGE_H
#define __ASM_AVR32_PAGE_H
#include <linux/const.h>
/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT 12
#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
#define PTE_MASK PAGE_MASK
#ifndef __ASSEMBLY__
#include <asm/addrspace.h>
extern void clear_page(void *to);
extern void copy_page(void *to, void *from);
#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
/*
* These are used to make use of C type-checking..
*/
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pgd; } pgd_t;
typedef struct { unsigned long pgprot; } pgprot_t;
typedef struct page *pgtable_t;
#define pte_val(x) ((x).pte)
#define pgd_val(x) ((x).pgd)
#define pgprot_val(x) ((x).pgprot)
#define __pte(x) ((pte_t) { (x) })
#define __pgd(x) ((pgd_t) { (x) })
#define __pgprot(x) ((pgprot_t) { (x) })
/* FIXME: These should be removed soon */
extern unsigned long memory_start, memory_end;
/* Pure 2^n version of get_order */
static inline int get_order(unsigned long size)
{
unsigned lz;
size = (size - 1) >> PAGE_SHIFT;
asm("clz %0, %1" : "=r"(lz) : "r"(size));
return 32 - lz;
}
#endif /* !__ASSEMBLY__ */
/*
* The hardware maps the virtual addresses 0x80000000 -> 0x9fffffff
* permanently to the physical addresses 0x00000000 -> 0x1fffffff when
* segmentation is enabled. We want to make use of this in order to
* minimize TLB pressure.
*/
#define PAGE_OFFSET (0x80000000UL)
/*
* ALSA uses virt_to_page() on DMA pages, which I'm not entirely sure
* is a good idea. Anyway, we can't simply subtract PAGE_OFFSET here
* in that case, so we'll have to mask out the three most significant
* bits of the address instead...
*
* What's the difference between __pa() and virt_to_phys() anyway?
*/
#define __pa(x) PHYSADDR(x)
#define __va(x) ((void *)(P1SEGADDR(x)))
#define MAP_NR(addr) (((unsigned long)(addr) - PAGE_OFFSET) >> PAGE_SHIFT)
#define phys_to_page(phys) (pfn_to_page(phys >> PAGE_SHIFT))
#define page_to_phys(page) (page_to_pfn(page) << PAGE_SHIFT)
#ifndef CONFIG_NEED_MULTIPLE_NODES
#define PHYS_PFN_OFFSET (CONFIG_PHYS_OFFSET >> PAGE_SHIFT)
#define pfn_to_page(pfn) (mem_map + ((pfn) - PHYS_PFN_OFFSET))
#define page_to_pfn(page) ((unsigned long)((page) - mem_map) + PHYS_PFN_OFFSET)
#define pfn_valid(pfn) ((pfn) >= PHYS_PFN_OFFSET && (pfn) < (PHYS_PFN_OFFSET + max_mapnr))
#endif /* CONFIG_NEED_MULTIPLE_NODES */
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
/*
* Memory above this physical address will be considered highmem.
*/
#define HIGHMEM_START 0x20000000UL
#endif /* __ASM_AVR32_PAGE_H */