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authorRoland Dreier <rolandd@cisco.com>2005-10-28 17:46:18 -0700
committerPaul Mackerras <paulus@samba.org>2005-10-29 14:25:49 +1000
commit8b150478aeb1a8edb9015c2f7ac4da637ff65c45 (patch)
tree621b038b9c041fe82b708c6c5cbee655be2a519a /arch/ppc/mm
parentd49b340124a34fcb8bceda472558ccef7232c16f (diff)
downloadlinux-linaro-stable-8b150478aeb1a8edb9015c2f7ac4da637ff65c45.tar.gz
[PATCH] ppc: make phys_mem_access_prot() work with pfns instead of addresses
Change the phys_mem_access_prot() function to take a pfn instead of an address. This allows mmap64() to work on /dev/mem for addresses above 4G on 32-bit architectures. We start with a pfn in mmap_mem(), so there's no need to convert to an address; in fact, it's actively bad, since the conversion can overflow when the address is above 4G. Similarly fix the ppc32 page_is_ram() function to avoid a conversion to an address by directly comparing to max_pfn. Working with max_pfn instead of high_memory fixes page_is_ram() to give the right answer for highmem pages. Signed-off-by: Roland Dreier <rolandd@cisco.com> Cc: Anton Blanchard <anton@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/ppc/mm')
-rw-r--r--arch/ppc/mm/init.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/arch/ppc/mm/init.c b/arch/ppc/mm/init.c
index db94efd25369..99b48abd3296 100644
--- a/arch/ppc/mm/init.c
+++ b/arch/ppc/mm/init.c
@@ -637,18 +637,16 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
*/
int page_is_ram(unsigned long pfn)
{
- unsigned long paddr = (pfn << PAGE_SHIFT);
-
- return paddr < __pa(high_memory);
+ return pfn < max_pfn;
}
-pgprot_t phys_mem_access_prot(struct file *file, unsigned long addr,
+pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
unsigned long size, pgprot_t vma_prot)
{
if (ppc_md.phys_mem_access_prot)
- return ppc_md.phys_mem_access_prot(file, addr, size, vma_prot);
+ return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);
- if (!page_is_ram(addr >> PAGE_SHIFT))
+ if (!page_is_ram(pfn))
vma_prot = __pgprot(pgprot_val(vma_prot)
| _PAGE_GUARDED | _PAGE_NO_CACHE);
return vma_prot;