Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc update from Benjamin Herrenschmidt:
 "Just so that you don't get too bored on your Island here's a patch for
  3.8 fixing a nasty bug that affects the new 64T support that was
  merged in 3.7.  Please apply whenever you have a chance (and an
  internet connection!)"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/mm: Fix hash computation function

1 files changed, 35 insertions, 27 deletions

diff --git a/arch/powerpc/mm/hash_low_64.S b/arch/powerpc/mm/hash_low_64.S
index 56585086413a..7443481a315c 100644
--- a/arch/powerpc/mm/hash_low_64.S
+++ b/arch/powerpc/mm/hash_low_64.S
@@ -115,11 +115,13 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
         sldi    r29,r5,SID_SHIFT - VPN_SHIFT
         rldicl  r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
         or      r29,r28,r29
-
-        /* Calculate hash value for primary slot and store it in r28 */
-        rldicl  r5,r5,0,25              /* vsid & 0x0000007fffffffff */
-        rldicl  r0,r3,64-12,48          /* (ea >> 12) & 0xffff */
-        xor     r28,r5,r0
+        /*
+         * Calculate hash value for primary slot and store it in r28
+         * r3 = va, r5 = vsid
+         * r0 = (va >> 12) & ((1ul << (28 - 12)) -1)
+         */
+        rldicl  r0,r3,64-12,48
+        xor     r28,r5,r0               /* hash */
         b       4f
 
 3:      /* Calc vpn and put it in r29 */
@@ -130,11 +132,12 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
         /*
          * calculate hash value for primary slot and
          * store it in r28 for 1T segment
+         * r3 = va, r5 = vsid
          */
-        rldic   r28,r5,25,25            /* (vsid << 25) & 0x7fffffffff */
-        clrldi  r5,r5,40                /* vsid & 0xffffff */
-        rldicl  r0,r3,64-12,36          /* (ea >> 12) & 0xfffffff */
-        xor     r28,r28,r5
+        sldi    r28,r5,25               /* vsid << 25 */
+        /* r0 =  (va >> 12) & ((1ul << (40 - 12)) -1) */
+        rldicl  r0,r3,64-12,36
+        xor     r28,r28,r5              /* vsid ^ ( vsid << 25) */
         xor     r28,r28,r0              /* hash */
 
         /* Convert linux PTE bits into HW equivalents */
@@ -407,11 +410,13 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
          */
         rldicl  r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
         or      r29,r28,r29
-
-        /* Calculate hash value for primary slot and store it in r28 */
-        rldicl  r5,r5,0,25              /* vsid & 0x0000007fffffffff */
-        rldicl  r0,r3,64-12,48          /* (ea >> 12) & 0xffff */
-        xor     r28,r5,r0
+        /*
+         * Calculate hash value for primary slot and store it in r28
+         * r3 = va, r5 = vsid
+         * r0 = (va >> 12) & ((1ul << (28 - 12)) -1)
+         */
+        rldicl  r0,r3,64-12,48
+        xor     r28,r5,r0               /* hash */
         b       4f
 
 3:      /* Calc vpn and put it in r29 */
@@ -426,11 +431,12 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
         /*
          * Calculate hash value for primary slot and
          * store it in r28  for 1T segment
+         * r3 = va, r5 = vsid
          */
-        rldic   r28,r5,25,25            /* (vsid << 25) & 0x7fffffffff */
-        clrldi  r5,r5,40                /* vsid & 0xffffff */
-        rldicl  r0,r3,64-12,36          /* (ea >> 12) & 0xfffffff */
-        xor     r28,r28,r5
+        sldi    r28,r5,25               /* vsid << 25 */
+        /* r0 = (va >> 12) & ((1ul << (40 - 12)) -1) */
+        rldicl  r0,r3,64-12,36
+        xor     r28,r28,r5              /* vsid ^ ( vsid << 25) */
         xor     r28,r28,r0              /* hash */
 
         /* Convert linux PTE bits into HW equivalents */
@@ -752,25 +758,27 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
         rldicl  r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
         or      r29,r28,r29
 
-        /* Calculate hash value for primary slot and store it in r28 */
-        rldicl  r5,r5,0,25              /* vsid & 0x0000007fffffffff */
-        rldicl  r0,r3,64-16,52          /* (ea >> 16) & 0xfff */
-        xor     r28,r5,r0
+        /* Calculate hash value for primary slot and store it in r28
+         * r3 = va, r5 = vsid
+         * r0 = (va >> 16) & ((1ul << (28 - 16)) -1)
+         */
+        rldicl  r0,r3,64-16,52
+        xor     r28,r5,r0               /* hash */
         b       4f
 
 3:      /* Calc vpn and put it in r29 */
         sldi    r29,r5,SID_SHIFT_1T - VPN_SHIFT
         rldicl  r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT_1T - VPN_SHIFT)
         or      r29,r28,r29
-
         /*
          * calculate hash value for primary slot and
          * store it in r28 for 1T segment
+         * r3 = va, r5 = vsid
          */
-        rldic   r28,r5,25,25            /* (vsid << 25) & 0x7fffffffff */
-        clrldi  r5,r5,40                /* vsid & 0xffffff */
-        rldicl  r0,r3,64-16,40          /* (ea >> 16) & 0xffffff */
-        xor     r28,r28,r5
+        sldi    r28,r5,25               /* vsid << 25 */
+        /* r0 = (va >> 16) & ((1ul << (40 - 16)) -1) */
+        rldicl  r0,r3,64-16,40
+        xor     r28,r28,r5              /* vsid ^ ( vsid << 25) */
         xor     r28,r28,r0              /* hash */
 
         /* Convert linux PTE bits into HW equivalents */