powerpc/fsl-booke: Fix InstructionTLBError execute permission check

In CONFIG_PTE_64BIT the PTE format has unique permission bits for user
and supervisor execute.  However on !CONFIG_PTE_64BIT we overload the
supervisor bit to imply user execute with _PAGE_USER set.  This allows
us to use the same permission check mask for user or supervisor code on
!CONFIG_PTE_64BIT.

However, on CONFIG_PTE_64BIT we map _PAGE_EXEC to _PAGE_BAP_UX so we
need a different permission mask based on the fault coming from a kernel
address or user space.

Without unique permission masks we see issues like the following with
modules:

Unable to handle kernel paging request for instruction fetch
Faulting instruction address: 0xf938d040
Oops: Kernel access of bad area, sig: 11 [#1]

Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Jin Qing <b24347@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 10 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 725526547994..edd4a57fd29e 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -639,6 +639,13 @@ interrupt_base:
         rlwinm  r12,r12,0,16,1
         mtspr   SPRN_MAS1,r12
 
+        /* Make up the required permissions for kernel code */
+#ifdef CONFIG_PTE_64BIT
+        li      r13,_PAGE_PRESENT | _PAGE_BAP_SX
+        oris    r13,r13,_PAGE_ACCESSED@h
+#else
+        li      r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
+#endif
         b       4f
 
         /* Get the PGD for the current thread */
@@ -646,15 +653,15 @@ interrupt_base:
         mfspr   r11,SPRN_SPRG_THREAD
         lwz     r11,PGDIR(r11)
 
-4:
-        /* Make up the required permissions */
+        /* Make up the required permissions for user code */
 #ifdef CONFIG_PTE_64BIT
-        li      r13,_PAGE_PRESENT | _PAGE_EXEC
+        li      r13,_PAGE_PRESENT | _PAGE_BAP_UX
         oris    r13,r13,_PAGE_ACCESSED@h
 #else
         li      r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
 #endif
 
+4:
         FIND_PTE
         andc.   r13,r13,r11             /* Check permission */