[PATCH] make valid_mmap_phys_addr_range() take a pfn

Newer ARMs have a 40 bit physical address space, but mapping physical
memory above 4G needs a special page table format which we (currently?) do
not use for userspace mappings, so what happens instead is that mapping an
address >= 4G will happily discard the upper bits and wrap.

There is a valid_mmap_phys_addr_range() arch hook where we could check for
>= 4G addresses and deny the mapping, but this hook takes an unsigned long
address:

	static inline int valid_mmap_phys_addr_range(unsigned long addr, size_t size);

And drivers/char/mem.c:mmap_mem() calls it like this:

	static int mmap_mem(struct file * file, struct vm_area_struct * vma)
	{
		size_t size = vma->vm_end - vma->vm_start;

		if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, size))

So that's not much help either.

This patch makes the hook take a pfn instead of a phys address.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index e97c32ceb796..917b20402664 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -95,7 +95,7 @@ static inline int valid_phys_addr_range(unsigned long addr, size_t count)
         return 1;
 }
 
-static inline int valid_mmap_phys_addr_range(unsigned long addr, size_t size)
+static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 {
         return 1;
 }
@@ -242,7 +242,7 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 {
         size_t size = vma->vm_end - vma->vm_start;
 
-        if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, size))
+        if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
                 return -EINVAL;
 
         vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,