From patchwork Tue Jan 20 09:57:33 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 430942 X-Patchwork-Delegate: scottwood@freescale.com Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 9F38B1402DF for ; Tue, 20 Jan 2015 21:01:48 +1100 (AEDT) Received: from ozlabs.org (ozlabs.org [103.22.144.67]) by lists.ozlabs.org (Postfix) with ESMTP id 80DD71A111D for ; Tue, 20 Jan 2015 21:01:48 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mailhub1.si.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by lists.ozlabs.org (Postfix) with ESMTP id 028C81A0C56 for ; Tue, 20 Jan 2015 20:57:37 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id D3EA81C81A7; Tue, 20 Jan 2015 10:57:35 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from mailhub1.si.c-s.fr ([192.168.12.234]) by localhost (mailhub1.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id oaVLC80XJpUx; Tue, 20 Jan 2015 10:57:35 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id A1D471C81A9; Tue, 20 Jan 2015 10:57:35 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4D774C73CD; Tue, 20 Jan 2015 10:57:35 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id NzkqLS8warAx; Tue, 20 Jan 2015 10:57:35 +0100 (CET) Received: from PO10863.localdomain (unknown [172.25.231.75]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C5D36C73C5; Tue, 20 Jan 2015 10:57:34 +0100 (CET) Received: by localhost.localdomain (Postfix, from userid 0) id E60091A5E85; Tue, 20 Jan 2015 10:57:33 +0100 (CET) From: Christophe Leroy To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , scottwood@freescale.com Subject: [PATCH v2 02/11] powerpc/8xx: remove tests on PGDIR entry validity Message-Id: <20150120095733.E60091A5E85@localhost.localdomain> Date: Tue, 20 Jan 2015 10:57:33 +0100 (CET) Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Kernel MMU handling code handles validity of entries via _PMD_PRESENT which corresponds to V bit in MD_TWC and MI_TWC. When the V bit is not set, MPC8xx triggers TLBError exception. So we don't have to check that and branch ourself to TLBError. We can set TLB entries with non present entries, remove all those tests and let the 8xx handle it. This reduce the number of cycle when the entries are valid which is the case most of the time, and doesn't significantly increase the time for handling invalid entries. Signed-off-by: Christophe Leroy --- v2: no change arch/powerpc/kernel/head_8xx.S | 41 ++++++++--------------------------------- 1 file changed, 8 insertions(+), 33 deletions(-) diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 79b8a23..2c329f1 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -329,12 +329,9 @@ InstructionTLBMiss: /* Extract level 1 index */ rlwinm r10, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29 lwzx r11, r10, r11 /* Get the level 1 entry */ - rlwinm. r10, r11,0,0,19 /* Extract page descriptor page address */ - beq 2f /* If zero, don't try to find a pte */ + rlwinm r10, r11,0,0,19 /* Extract page descriptor page address */ - /* We have a pte table, so load the MI_TWC with the attributes - * for this "segment." - */ + /* Load the MI_TWC with the attributes for this "segment." */ MTSPR_CPU6(SPRN_MI_TWC, r11, r3) /* Set segment attributes */ mfspr r11, SPRN_SRR0 /* Get effective address of fault */ /* Extract level 2 index */ @@ -342,13 +339,11 @@ InstructionTLBMiss: lwzx r10, r10, r11 /* Get the pte */ #ifdef CONFIG_SWAP - andi. r11, r10, _PAGE_ACCESSED | _PAGE_PRESENT - cmpwi cr0, r11, _PAGE_ACCESSED | _PAGE_PRESENT - li r11, RPN_PATTERN - bne- cr0, 2f -#else - li r11, RPN_PATTERN + rlwinm r11, r10, 32-5, _PAGE_PRESENT + and r11, r11, r10 + rlwimi r10, r11, 0, _PAGE_PRESENT #endif + li r11, RPN_PATTERN /* The Linux PTE won't go exactly into the MMU TLB. * Software indicator bits 21 and 28 must be clear. * Software indicator bits 24, 25, 26, and 27 must be @@ -366,21 +361,6 @@ InstructionTLBMiss: mfspr r10, SPRN_SPRG_SCRATCH2 EXCEPTION_EPILOG_0 rfi -2: - mfspr r10, SPRN_SRR1 - /* clear all error bits as TLB Miss - * sets a few unconditionally - */ - rlwinm r10, r10, 0, 0xffff - mtspr SPRN_SRR1, r10 - - /* Restore registers */ -#ifdef CONFIG_8xx_CPU6 - mfspr r3, SPRN_DAR - mtspr SPRN_DAR, r11 /* Tag DAR */ -#endif - mfspr r10, SPRN_SPRG_SCRATCH2 - b InstructionTLBError1 . = 0x1200 DataStoreTLBMiss: @@ -403,8 +383,6 @@ DataStoreTLBMiss: /* Extract level 1 index */ rlwinm r10, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29 lwzx r11, r10, r11 /* Get the level 1 entry */ - rlwinm. r10, r11,0,0,19 /* Extract page descriptor page address */ - beq 2f /* If zero, don't try to find a pte */ /* We have a pte table, so load fetch the pte from the table. */ @@ -450,7 +428,7 @@ DataStoreTLBMiss: * set. All other Linux PTE bits control the behavior * of the MMU. */ -2: li r11, RPN_PATTERN + li r11, RPN_PATTERN rlwimi r10, r11, 0, 24, 28 /* Set 24-27, clear 28 */ MTSPR_CPU6(SPRN_MD_RPN, r10, r3) /* Update TLB entry */ @@ -469,10 +447,7 @@ DataStoreTLBMiss: */ . = 0x1300 InstructionTLBError: - EXCEPTION_PROLOG_0 -InstructionTLBError1: - EXCEPTION_PROLOG_1 - EXCEPTION_PROLOG_2 + EXCEPTION_PROLOG mr r4,r12 mr r5,r9 andis. r10,r5,0x4000