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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2013-01-29 19:40:42 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-02-04 15:15:08 +1100
commiteda8eebdd153c48a4e2a3a3ac3cd9e2e31f5c6b3 (patch)
tree7de4fea5e76746a88043c726e6aba7b98ea687bc /arch
parent689dfa894c57842a05bf6dc9f97e6bb71ec5f386 (diff)
powerpc/mm: Fix hash computation function
The ASM version of hash computation function was truncating the upper bit. Make the ASM version similar to hpt_hash function. Remove masking vsid bits. Without this patch, we observed hang during bootup due to not satisfying page fault request correctly. The fault handler used wrong hash values to update the HPTE. Hence we kept looping with page fault. hash_page(ea=000001003e260008, access=203, trap=300 ip=3fff91787134 dsisr 42000000 The computed value of hash 000000000f22f390 update: avpnv=4003e46054003e00, hash=000000000722f390, f=80000006, psize: 2 ... BenH: The over-masking has been there for ever but only hurts with the new 64T support introduced in 3.7 Reported-by: Mike Qiu <qiudayu@linux.vnet.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Tested-by: Mike Qiu <qiudayu@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: <stable@vger.kernel.org> [v3.7]
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/mm/hash_low_64.S62
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 56585086413..7443481a315 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 */