[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>

2 files changed, 2 insertions, 2 deletions

diff --git a/include/asm-ppc64/pci.h b/include/asm-ppc64/pci.h
index a88bbfc26967..342e2d755550 100644
--- a/include/asm-ppc64/pci.h
+++ b/include/asm-ppc64/pci.h
@@ -168,7 +168,7 @@ extern void pcibios_add_platform_entries(struct pci_dev *dev);
 
 struct file;
 extern pgprot_t pci_phys_mem_access_prot(struct file *file,
-                                         unsigned long offset,
+                                         unsigned long pfn,
                                          unsigned long size,
                                          pgprot_t prot);
 
diff --git a/include/asm-ppc64/pgtable.h b/include/asm-ppc64/pgtable.h
index c83679c9d2b0..8cf5991540e3 100644
--- a/include/asm-ppc64/pgtable.h
+++ b/include/asm-ppc64/pgtable.h
@@ -471,7 +471,7 @@ static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry, int dirty)
 #define pgprot_noncached(prot)  (__pgprot(pgprot_val(prot) | _PAGE_NO_CACHE | _PAGE_GUARDED))
 
 struct file;
-extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long addr,
+extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
                                      unsigned long size, pgprot_t vma_prot);
 #define __HAVE_PHYS_MEM_ACCESS_PROT