mm: Allow architectures to define additional protection bits
This patch allows architectures to define functions to deal with
additional protections bits for mmap() and mprotect().
arch_calc_vm_prot_bits() maps additonal protection bits to vm_flags
arch_vm_get_page_prot() maps additional vm_flags to the vma's vm_page_prot
arch_validate_prot() checks for valid values of the protection bits
Note: vm_get_page_prot() is now pretty ugly, but the generated code
should be identical for architectures that don't define additional
protection bits.
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/mm/mmap.c b/mm/mmap.c
index 3354fdd..1d102b9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -72,8 +72,9 @@
pgprot_t vm_get_page_prot(unsigned long vm_flags)
{
- return protection_map[vm_flags &
- (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+ return __pgprot(pgprot_val(protection_map[vm_flags &
+ (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
+ pgprot_val(arch_vm_get_page_prot(vm_flags)));
}
EXPORT_SYMBOL(vm_get_page_prot);