From patchwork Tue May 19 05:49:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1293011 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49R6J16pXVz9sT4 for ; Tue, 19 May 2020 17:01:53 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=csgroup.eu Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49R6J12FCLzDqVV for ; Tue, 19 May 2020 17:01:53 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=csgroup.eu (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@csgroup.eu; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=csgroup.eu Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49R4hN3N8gzDqW6 for ; Tue, 19 May 2020 15:49:24 +1000 (AEST) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 49R4hJ3XM0z9txm0; Tue, 19 May 2020 07:49:20 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id IwhKBM4a27U6; Tue, 19 May 2020 07:49:20 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 49R4hJ2m6dz9txlx; Tue, 19 May 2020 07:49:20 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 73E438B7A7; Tue, 19 May 2020 07:49:21 +0200 (CEST) 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 IJD4e6qqNMiY; Tue, 19 May 2020 07:49:21 +0200 (CEST) Received: from pc16570vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 430128B767; Tue, 19 May 2020 07:49:21 +0200 (CEST) Received: by pc16570vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 1F9F065A4A; Tue, 19 May 2020 05:49:20 +0000 (UTC) Message-Id: <6312575d06a8813105e6564a3b12e1d373aa1b2f.1589866984.git.christophe.leroy@csgroup.eu> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v4 37/45] powerpc/8xx: Refactor kernel address boundary comparison To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Date: Tue, 19 May 2020 05:49:20 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Now that linear and IMMR dedicated TLB handling is gone, kernel boundary address comparison is similar in ITLB miss handler and in DTLB miss handler. Create a macro named compare_to_kernel_boundary. When TASK_SIZE is strictly below 0x80000000 and PAGE_OFFSET is above 0x80000000, it is enough to compare to 0x8000000, and this can be done with a single instruction. Using not. instruction, we get to use 'blt' conditional branch as when doing a regular comparison: 0x00000000 <= addr <= 0x7fffffff ==> 0xffffffff >= NOT(addr) >= 0x80000000 The above test corresponds to a 'blt' Otherwise, do a regular comparison using two instructions. Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/head_8xx.S | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 9f3f7f3d03a7..9a117b9f0998 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -32,10 +32,15 @@ #include "head_32.h" +.macro compare_to_kernel_boundary scratch, addr #if CONFIG_TASK_SIZE <= 0x80000000 && CONFIG_PAGE_OFFSET >= 0x80000000 /* By simply checking Address >= 0x80000000, we know if its a kernel address */ -#define SIMPLE_KERNEL_ADDRESS 1 + not. \scratch, \addr +#else + rlwinm \scratch, \addr, 16, 0xfff8 + cmpli cr0, \scratch, PAGE_OFFSET@h #endif +.endm /* * We need an ITLB miss handler for kernel addresses if: @@ -209,20 +214,11 @@ InstructionTLBMiss: mtspr SPRN_MD_EPN, r10 #ifdef ITLB_MISS_KERNEL mfcr r11 -#if defined(SIMPLE_KERNEL_ADDRESS) - cmpi cr0, r10, 0 /* Address >= 0x80000000 */ -#else - rlwinm r10, r10, 16, 0xfff8 - cmpli cr0, r10, PAGE_OFFSET@h -#endif + compare_to_kernel_boundary r10, r10 #endif mfspr r10, SPRN_M_TWB /* Get level 1 table */ #ifdef ITLB_MISS_KERNEL -#if defined(SIMPLE_KERNEL_ADDRESS) - bge+ 3f -#else blt+ 3f -#endif rlwinm r10, r10, 0, 20, 31 oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha 3: @@ -288,9 +284,7 @@ DataStoreTLBMiss: * kernel page tables. */ mfspr r10, SPRN_MD_EPN - rlwinm r10, r10, 16, 0xfff8 - cmpli cr0, r10, PAGE_OFFSET@h - + compare_to_kernel_boundary r10, r10 mfspr r10, SPRN_M_TWB /* Get level 1 table */ blt+ 3f rlwinm r10, r10, 0, 20, 31