| From eda8eebdd153c48a4e2a3a3ac3cd9e2e31f5c6b3 Mon Sep 17 00:00:00 2001 |
| From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> |
| Date: Tue, 29 Jan 2013 19:40:42 +0000 |
| Subject: powerpc/mm: Fix hash computation function |
| |
| From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> |
| |
| commit eda8eebdd153c48a4e2a3a3ac3cd9e2e31f5c6b3 upstream. |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/powerpc/mm/hash_low_64.S | 62 +++++++++++++++++++++++------------------- |
| 1 file changed, 35 insertions(+), 27 deletions(-) |
| |
| --- 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_SEG |
| 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_SEG |
| /* |
| * 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_SEG |
| */ |
| 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_SEG |
| /* |
| * 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_SEG |
| 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 */ |
