powerpc/8xx: DTLB Miss cleanup

Use symbolic constant for PRESENT and avoid branching.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 6 deletions

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index f2de8e8a825c..678f98cd5e64 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -438,15 +438,20 @@ DataStoreTLBMiss:
          * r11 = ((r10 & PRESENT) & ((r10 & ACCESSED) >> 5));
          * r10 = (r10 & ~PRESENT) | r11;
          */
-        rlwinm  r11, r10, 32-5, 31, 31
+        rlwinm  r11, r10, 32-5, _PAGE_PRESENT
         and     r11, r11, r10
-        rlwimi  r10, r11, 0, 31, 31
+        rlwimi  r10, r11, 0, _PAGE_PRESENT
 
         /* Honour kernel RO, User NA */
-        andi.   r11, r10, _PAGE_USER | _PAGE_RW
-        bne-    cr0, 5f
-        ori     r10,r10, 0x200 /* Extended encoding, bit 22 */
-5:      xori    r10, r10, _PAGE_RW  /* invert RW bit */
+        /* 0x200 == Extended encoding, bit 22 */
+        /* r11 =  (r10 & _PAGE_USER) >> 2 */
+        rlwinm  r11, r10, 32-2, 0x200
+        or      r10, r11, r10
+        /* r11 =  (r10 & _PAGE_RW) >> 1 */
+        rlwinm  r11, r10, 32-1, 0x200
+        or      r10, r11, r10
+        /* invert RW and 0x200 bits */
+        xori    r10, r10, _PAGE_RW | 0x200
 
         /* The Linux PTE won't go exactly into the MMU TLB.
          * Software indicator bits 22 and 28 must be clear.