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 991A72C008F for ; Wed, 30 Jan 2013 18:24:06 +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 17:20:31 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 5B1492CE804D for ; Wed, 30 Jan 2013 18:24:00 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0U7C51D2687434 for ; Wed, 30 Jan 2013 18:12:05 +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 r0U7Nw1f016387 for ; Wed, 30 Jan 2013 18:23:59 +1100 Message-ID: <5108CA89.4080305@linux.vnet.ibm.com> Date: Wed, 30 Jan 2013 15:23:53 +0800 From: Mike Qiu MIME-Version: 1.0 To: linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] powerpc/mm: Fix hash computation function References: <1359524442-5861-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> In-Reply-To: <1359524442-5861-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Content-Type: text/plain; charset=GB2312 Cc: paulus@samba.org, "Aneesh Kumar K.V" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , With the fix, the machine can boot up successfully Tested-by: Mike Qiu ÓÚ 2013/1/30 13:40, Aneesh Kumar K.V дµÀ: > 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 */