[PATCH 10/12] x86, pkeys: differentiate Protection Key faults from normal

[Dave Hansen <dave@sr71.net>]

---

 b/arch/x86/mm/fault.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff -puN arch/x86/mm/fault.c~pkeys-12-fault-differentiation arch/x86/mm/fault.c
--- a/arch/x86/mm/fault.c~pkeys-12-fault-differentiation	2015-05-07 10:31:44.570330979 -0700
+++ b/arch/x86/mm/fault.c	2015-05-07 10:31:44.573331114 -0700
@@ -1009,6 +1009,15 @@ int show_unhandled_signals = 1;
 static inline int
 access_error(unsigned long error_code, struct vm_area_struct *vma)
 {
+	/*
+	 * Access or read was blocked by protection keys. We do
+	 * this check before any others because we do not want
+	 * to, for instance, confuse a protection-key-denied
+	 * write with one for which we should do a COW.
+	 */
+	if (error_code & PF_PK)
+		return 1;
+
 	if (error_code & PF_WRITE) {
 		/* write, present and write, not present: */
 		if (unlikely(!(vma->vm_flags & VM_WRITE)))
_