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[PATCH] ppc: make phys_mem_access_prot() work with pfns instead of addresses

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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>
This commit is contained in:
Roland Dreier
2005-10-28 17:46:18 -07:00
committed by Paul Mackerras
parent d49b340124
commit 8b150478ae
12 changed files with 21 additions and 23 deletions
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6
arch/powerpc/mm/mem.c
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@ -88,13 +88,13 @@ int page_is_ram(unsigned long pfn)
}
EXPORT_SYMBOL(page_is_ram);
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;