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linux-next/arch/avr32/mm/ioremap.c
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

93 lines
2.3 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.
*/
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/io.h>
#include <asm/pgtable.h>
#include <asm/addrspace.h>
/*
* Re-map an arbitrary physical address space into the kernel virtual
* address space. Needed when the kernel wants to access physical
* memory directly.
*/
void __iomem *__ioremap(unsigned long phys_addr, size_t size,
unsigned long flags)
{
unsigned long addr;
struct vm_struct *area;
unsigned long offset, last_addr;
pgprot_t prot;
/*
* Check if we can simply use the P4 segment. This area is
* uncacheable, so if caching/buffering is requested, we can't
* use it.
*/
if ((phys_addr >= P4SEG) && (flags == 0))
return (void __iomem *)phys_addr;
/* Don't allow wraparound or zero size */
last_addr = phys_addr + size - 1;
if (!size || last_addr < phys_addr)
return NULL;
/*
* XXX: When mapping regular RAM, we'd better make damn sure
* it's never used for anything else. But this is really the
* caller's responsibility...
*/
if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr)
return (void __iomem *)P2SEGADDR(phys_addr);
/* Mappings have to be page-aligned */
offset = phys_addr & ~PAGE_MASK;
phys_addr &= PAGE_MASK;
size = PAGE_ALIGN(last_addr + 1) - phys_addr;
prot = __pgprot(_PAGE_PRESENT | _PAGE_GLOBAL | _PAGE_RW | _PAGE_DIRTY
| _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags);
/*
* Ok, go for it..
*/
area = get_vm_area(size, VM_IOREMAP);
if (!area)
return NULL;
area->phys_addr = phys_addr;
addr = (unsigned long )area->addr;
if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
vunmap((void *)addr);
return NULL;
}
return (void __iomem *)(offset + (char *)addr);
}
EXPORT_SYMBOL(__ioremap);
void __iounmap(void __iomem *addr)
{
struct vm_struct *p;
if ((unsigned long)addr >= P4SEG)
return;
if (PXSEG(addr) == P2SEG)
return;
p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
if (unlikely(!p)) {
printk (KERN_ERR "iounmap: bad address %p\n", addr);
return;
}
kfree (p);
}
EXPORT_SYMBOL(__iounmap);