[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>
diff --git a/arch/ppc/kernel/pci.c b/arch/ppc/kernel/pci.c
index ad4ef2a..e8f4e57 100644
--- a/arch/ppc/kernel/pci.c
+++ b/arch/ppc/kernel/pci.c
@@ -1594,16 +1594,17 @@
* 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;