powerpc/mm: Move page fault VMA access checks to a helper

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index ebe73c896aa84bfba4338d07ab7913f2d87ab933..da54887a74e978ccb5d830a6d14bdfc812d3234f 100644 (file)
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -222,6 +222,37 @@ static bool bad_kernel_fault(bool is_exec, unsigned long error_code,
        return is_exec || (address >= TASK_SIZE);
 }
 
+static bool access_error(bool is_write, bool is_exec,
+                        struct vm_area_struct *vma)
+{
+       /*
+        * Allow execution from readable areas if the MMU does not
+        * provide separate controls over reading and executing.
+        *
+        * Note: That code used to not be enabled for 4xx/BookE.
+        * It is now as I/D cache coherency for these is done at
+        * set_pte_at() time and I see no reason why the test
+        * below wouldn't be valid on those processors. This -may-
+        * break programs compiled with a really old ABI though.
+        */
+       if (is_exec) {
+               return !(vma->vm_flags & VM_EXEC) &&
+                       (cpu_has_feature(CPU_FTR_NOEXECUTE) ||
+                        !(vma->vm_flags & (VM_READ | VM_WRITE)));
+       }
+
+       if (is_write) {
+               if (unlikely(!(vma->vm_flags & VM_WRITE)))
+                       return true;
+               return false;
+       }
+
+       if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
+               return true;
+
+       return false;
+}
+
 #ifdef CONFIG_PPC_SMLPAR
 static inline void cmo_account_page_fault(void)
 {
@@ -461,30 +492,8 @@ retry:
                return bad_area(regs, address);
 
 good_area:
-       if (is_exec) {
-               /*
-                * Allow execution from readable areas if the MMU does not
-                * provide separate controls over reading and executing.
-                *
-                * Note: That code used to not be enabled for 4xx/BookE.
-                * It is now as I/D cache coherency for these is done at
-                * set_pte_at() time and I see no reason why the test
-                * below wouldn't be valid on those processors. This -may-
-                * break programs compiled with a really old ABI though.
-                */
-               if (unlikely(!(vma->vm_flags & VM_EXEC) &&
-                            (cpu_has_feature(CPU_FTR_NOEXECUTE) ||
-                             !(vma->vm_flags & (VM_READ | VM_WRITE)))))
-                       return bad_area(regs, address);
-       /* a write */
-       } else if (is_write) {
-               if (unlikely(!(vma->vm_flags & VM_WRITE)))
-                       return bad_area(regs, address);
-       /* a read */
-       } else {
-               if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
-                       return bad_area(regs, address);
-       }
+       if (unlikely(access_error(is_write, is_exec, vma)))
+               return bad_area(regs, address);
 
        /*
         * If for any reason at all we couldn't handle the fault,