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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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5
arch/ppc/kernel/pci.c
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@@ -1594,16 +1594,17 @@ static pgprot_t __pci_mmap_set_pgprot(struct pci_dev *dev, struct resource *rp,
* above routine
*/
pgprot_t pci_phys_mem_access_prot(struct file *file,
unsigned long offset,
unsigned long pfn,
unsigned long size,
pgprot_t protection)
{
struct pci_dev *pdev = NULL;
struct resource *found = NULL;
unsigned long prot = pgprot_val(protection);
unsigned long offset = pfn << PAGE_SHIFT;
int i;
if (page_is_ram(offset >> PAGE_SHIFT))
if (page_is_ram(pfn))
return prot;
prot |= _PAGE_NO_CACHE | _PAGE_GUARDED;