From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp05.au.ibm.com (e23smtp05.au.ibm.com [202.81.31.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp05.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 603082C0085 for ; Wed, 30 Jan 2013 16:41:15 +1100 (EST) Received: from /spool/local by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 30 Jan 2013 15:37:41 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 53D943578023 for ; Wed, 30 Jan 2013 16:41:08 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0U5T3jC9503034 for ; Wed, 30 Jan 2013 16:29:04 +1100 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r0U5f6Fc022181 for ; Wed, 30 Jan 2013 16:41:07 +1100 From: "Aneesh Kumar K.V" To: benh@kernel.crashing.org, paulus@samba.org Subject: [PATCH] powerpc/mm: Fix hash computation function Date: Wed, 30 Jan 2013 11:10:42 +0530 Message-Id: <1359524442-5861-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Cc: Mike Qiu , linuxppc-dev@lists.ozlabs.org, "Aneesh Kumar K.V" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Aneesh Kumar K.V" 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 ... Reported-by: Mike Qiu Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/mm/hash_low_64.S | 62 +++++++++++++++++++++++------------------ 1 file changed, 35 insertions(+), 27 deletions(-) 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 */ -- 1.7.10