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linux-next/arch/m68k/amiga/chipram.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

138 lines
3.3 KiB
C

/*
** linux/amiga/chipram.c
**
** Modified 03-May-94 by Geert Uytterhoeven <geert@linux-m68k.org>
** - 64-bit aligned allocations for full AGA compatibility
**
** Rewritten 15/9/2000 by Geert to use resource management
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/module.h>
#include <asm/page.h>
#include <asm/amigahw.h>
unsigned long amiga_chip_size;
EXPORT_SYMBOL(amiga_chip_size);
static struct resource chipram_res = {
.name = "Chip RAM", .start = CHIP_PHYSADDR
};
static unsigned long chipavail;
void __init amiga_chip_init(void)
{
if (!AMIGAHW_PRESENT(CHIP_RAM))
return;
/*
* Remove the first 4 pages where PPC exception handlers will be located
*/
amiga_chip_size -= 0x4000;
chipram_res.end = amiga_chip_size-1;
request_resource(&iomem_resource, &chipram_res);
chipavail = amiga_chip_size;
}
void *amiga_chip_alloc(unsigned long size, const char *name)
{
struct resource *res;
/* round up */
size = PAGE_ALIGN(size);
#ifdef DEBUG
printk("amiga_chip_alloc: allocate %ld bytes\n", size);
#endif
res = kzalloc(sizeof(struct resource), GFP_KERNEL);
if (!res)
return NULL;
res->name = name;
if (allocate_resource(&chipram_res, res, size, 0, UINT_MAX, PAGE_SIZE, NULL, NULL) < 0) {
kfree(res);
return NULL;
}
chipavail -= size;
#ifdef DEBUG
printk("amiga_chip_alloc: returning %lx\n", res->start);
#endif
return (void *)ZTWO_VADDR(res->start);
}
EXPORT_SYMBOL(amiga_chip_alloc);
/*
* Warning:
* amiga_chip_alloc_res is meant only for drivers that need to allocate
* Chip RAM before kmalloc() is functional. As a consequence, those
* drivers must not free that Chip RAM afterwards.
*/
void * __init amiga_chip_alloc_res(unsigned long size, struct resource *res)
{
unsigned long start;
/* round up */
size = PAGE_ALIGN(size);
/* dmesg into chipmem prefers memory at the safe end */
start = CHIP_PHYSADDR + chipavail - size;
#ifdef DEBUG
printk("amiga_chip_alloc_res: allocate %ld bytes\n", size);
#endif
if (allocate_resource(&chipram_res, res, size, start, UINT_MAX, PAGE_SIZE, NULL, NULL) < 0) {
printk("amiga_chip_alloc_res: first alloc failed!\n");
if (allocate_resource(&chipram_res, res, size, 0, UINT_MAX, PAGE_SIZE, NULL, NULL) < 0)
return NULL;
}
chipavail -= size;
#ifdef DEBUG
printk("amiga_chip_alloc_res: returning %lx\n", res->start);
#endif
return (void *)ZTWO_VADDR(res->start);
}
void amiga_chip_free(void *ptr)
{
unsigned long start = ZTWO_PADDR(ptr);
struct resource **p, *res;
unsigned long size;
for (p = &chipram_res.child; (res = *p); p = &res->sibling) {
if (res->start != start)
continue;
*p = res->sibling;
size = res->end-start;
#ifdef DEBUG
printk("amiga_chip_free: free %ld bytes at %p\n", size, ptr);
#endif
chipavail += size;
kfree(res);
return;
}
printk("amiga_chip_free: trying to free nonexistent region at %p\n", ptr);
}
EXPORT_SYMBOL(amiga_chip_free);
unsigned long amiga_chip_avail(void)
{
#ifdef DEBUG
printk("amiga_chip_avail : %ld bytes\n", chipavail);
#endif
return chipavail;
}
EXPORT_SYMBOL(amiga_chip_avail);