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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 /drivers/char/mem.c
parentd49b340124a34fcb8bceda472558ccef7232c16f (diff)
downloadop-kernel-dev-8b150478aeb1a8edb9015c2f7ac4da637ff65c45.zip
op-kernel-dev-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 'drivers/char/mem.c')
-rw-r--r--drivers/char/mem.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index f182752..9df928d 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -231,9 +231,7 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
static int mmap_mem(struct file * file, struct vm_area_struct * vma)
{
#if defined(__HAVE_PHYS_MEM_ACCESS_PROT)
- unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
-
- vma->vm_page_prot = phys_mem_access_prot(file, offset,
+ vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
vma->vm_end - vma->vm_start,
vma->vm_page_prot);
#elif defined(pgprot_noncached)
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