Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
arch/powerpc/mm/fault.c | 57 ++++++++++++++++++++++++++++---------------------
1 file changed, 33 insertions(+), 24 deletions(-)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 6a938fc8c5fb..2291686d24c6 100644
--- 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 @@ static int __do_page_fault(struct pt_regs *regs, unsigned
long address,
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,
--
2.13.3
