From: Aneesh Kumar K.V Date: Tue, 29 Jan 2013 19:40:42 +0000 (+0000) Subject: powerpc/mm: Fix hash computation function X-Git-Tag: v3.8-rc7~22^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=eda8eebdd153c48a4e2a3a3ac3cd9e2e31f5c6b3;p=profile%2Fivi%2Fkernel-adaptation-intel-automotive.git 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 Signed-off-by: Aneesh Kumar K.V Tested-by: Mike Qiu Signed-off-by: Benjamin Herrenschmidt CC: [v3.7] --- diff --git a/arch/powerpc/mm/hash_low_64.S b/arch/powerpc/mm/hash_low_64.S index 5658508..7443481 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 */