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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2013-01-29 14:40:42 -0500
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-02-03 23:15:08 -0500
commiteda8eebdd153c48a4e2a3a3ac3cd9e2e31f5c6b3 (patch)
tree7de4fea5e76746a88043c726e6aba7b98ea687bc /arch/powerpc/mm
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/powerpc/mm')
-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 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)
115 sldi r29,r5,SID_SHIFT - VPN_SHIFT 115 sldi r29,r5,SID_SHIFT - VPN_SHIFT
116 rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT) 116 rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
117 or r29,r28,r29 117 or r29,r28,r29
118 118 /*
119 /* Calculate hash value for primary slot and store it in r28 */ 119 * Calculate hash value for primary slot and store it in r28
120 rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */ 120 * r3 = va, r5 = vsid
121 rldicl r0,r3,64-12,48 /* (ea >> 12) & 0xffff */ 121 * r0 = (va >> 12) & ((1ul << (28 - 12)) -1)
122 xor r28,r5,r0 122 */
123 rldicl r0,r3,64-12,48
124 xor r28,r5,r0 /* hash */
123 b 4f 125 b 4f
124 126
1253: /* Calc vpn and put it in r29 */ 1273: /* Calc vpn and put it in r29 */
@@ -130,11 +132,12 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
130 /* 132 /*
131 * calculate hash value for primary slot and 133 * calculate hash value for primary slot and
132 * store it in r28 for 1T segment 134 * store it in r28 for 1T segment
135 * r3 = va, r5 = vsid
133 */ 136 */
134 rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */ 137 sldi r28,r5,25 /* vsid << 25 */
135 clrldi r5,r5,40 /* vsid & 0xffffff */ 138 /* r0 = (va >> 12) & ((1ul << (40 - 12)) -1) */
136 rldicl r0,r3,64-12,36 /* (ea >> 12) & 0xfffffff */ 139 rldicl r0,r3,64-12,36
137 xor r28,r28,r5 140 xor r28,r28,r5 /* vsid ^ ( vsid << 25) */
138 xor r28,r28,r0 /* hash */ 141 xor r28,r28,r0 /* hash */
139 142
140 /* Convert linux PTE bits into HW equivalents */ 143 /* Convert linux PTE bits into HW equivalents */
@@ -407,11 +410,13 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
407 */ 410 */
408 rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT) 411 rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
409 or r29,r28,r29 412 or r29,r28,r29
410 413 /*
411 /* Calculate hash value for primary slot and store it in r28 */ 414 * Calculate hash value for primary slot and store it in r28
412 rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */ 415 * r3 = va, r5 = vsid
413 rldicl r0,r3,64-12,48 /* (ea >> 12) & 0xffff */ 416 * r0 = (va >> 12) & ((1ul << (28 - 12)) -1)
414 xor r28,r5,r0 417 */
418 rldicl r0,r3,64-12,48
419 xor r28,r5,r0 /* hash */
415 b 4f 420 b 4f
416 421
4173: /* Calc vpn and put it in r29 */ 4223: /* Calc vpn and put it in r29 */
@@ -426,11 +431,12 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
426 /* 431 /*
427 * Calculate hash value for primary slot and 432 * Calculate hash value for primary slot and
428 * store it in r28 for 1T segment 433 * store it in r28 for 1T segment
434 * r3 = va, r5 = vsid
429 */ 435 */
430 rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */ 436 sldi r28,r5,25 /* vsid << 25 */
431 clrldi r5,r5,40 /* vsid & 0xffffff */ 437 /* r0 = (va >> 12) & ((1ul << (40 - 12)) -1) */
432 rldicl r0,r3,64-12,36 /* (ea >> 12) & 0xfffffff */ 438 rldicl r0,r3,64-12,36
433 xor r28,r28,r5 439 xor r28,r28,r5 /* vsid ^ ( vsid << 25) */
434 xor r28,r28,r0 /* hash */ 440 xor r28,r28,r0 /* hash */
435 441
436 /* Convert linux PTE bits into HW equivalents */ 442 /* Convert linux PTE bits into HW equivalents */
@@ -752,25 +758,27 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
752 rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT) 758 rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
753 or r29,r28,r29 759 or r29,r28,r29
754 760
755 /* Calculate hash value for primary slot and store it in r28 */ 761 /* Calculate hash value for primary slot and store it in r28
756 rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */ 762 * r3 = va, r5 = vsid
757 rldicl r0,r3,64-16,52 /* (ea >> 16) & 0xfff */ 763 * r0 = (va >> 16) & ((1ul << (28 - 16)) -1)
758 xor r28,r5,r0 764 */
765 rldicl r0,r3,64-16,52
766 xor r28,r5,r0 /* hash */
759 b 4f 767 b 4f
760 768
7613: /* Calc vpn and put it in r29 */ 7693: /* Calc vpn and put it in r29 */
762 sldi r29,r5,SID_SHIFT_1T - VPN_SHIFT 770 sldi r29,r5,SID_SHIFT_1T - VPN_SHIFT
763 rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT_1T - VPN_SHIFT) 771 rldicl r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT_1T - VPN_SHIFT)
764 or r29,r28,r29 772 or r29,r28,r29
765
766 /* 773 /*
767 * calculate hash value for primary slot and 774 * calculate hash value for primary slot and
768 * store it in r28 for 1T segment 775 * store it in r28 for 1T segment
776 * r3 = va, r5 = vsid
769 */ 777 */
770 rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */ 778 sldi r28,r5,25 /* vsid << 25 */
771 clrldi r5,r5,40 /* vsid & 0xffffff */ 779 /* r0 = (va >> 16) & ((1ul << (40 - 16)) -1) */
772 rldicl r0,r3,64-16,40 /* (ea >> 16) & 0xffffff */ 780 rldicl r0,r3,64-16,40
773 xor r28,r28,r5 781 xor r28,r28,r5 /* vsid ^ ( vsid << 25) */
774 xor r28,r28,r0 /* hash */ 782 xor r28,r28,r0 /* hash */
775 783
776 /* Convert linux PTE bits into HW equivalents */ 784 /* Convert linux PTE bits into HW equivalents */