Received: by 2002:a05:6a10:8c0a:0:0:0:0 with SMTP id go10csp4122852pxb; Mon, 8 Feb 2021 08:28:39 -0800 (PST) X-Google-Smtp-Source: ABdhPJz1JV8F4gyDQGLtYzHLOxJzT6cYdSMRZmFc8Ge24um91oQX+ftDsMtYWn+t/QfaLc6Tzytd X-Received: by 2002:a17:906:3499:: with SMTP id g25mr10767157ejb.367.1612801719441; Mon, 08 Feb 2021 08:28:39 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1612801719; cv=none; d=google.com; s=arc-20160816; b=UqYZ2Fs/ghYftGvgzZuO9ZFQfbjKquh9VNzd/Lsya7ZHk8cG/7sWlbCQPR6J18OPiR 6ta6IfOV0hhT22sLkwgvt0gTw4UAg9z/OgcdtMe2AUMjaiNEq+H+iFlTeuHJr0VVbN8l nX+hP/fDFwW77jibhNKjOaXTBGyG8BG8DKcELmlaMvkrEAJ/B70QwDWQ/ROPaV+1b3xv 5AkDDz2ah8rFJQYxrMwZ2fXnkmxVlVFQlsmI0+m6xxsVb2bFHbY4xZ/xYSGM6VDM9pMK jqhbeQzNH0111nMZMM2rlvPqQ0fU9ptou2oYHxNwaNsKpwyBhoAT+3jj2F/npSwbo8mm M2oQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:date:cc:to:subject:from:references:in-reply-to :message-id; bh=ROXAZedbxPM83dP5C/62UoldX9C4cQqYHX0KEzea5lo=; b=kAYAEkQqeH90b4JHrNW1B7oNjsZzo8dDKXvoAJ2FELtXUMLSECYrVYDLWEGBd0ZBl3 6PgL2R96fIBxD6OBuKCckISd9fTFNJB+j11lQQLIMemFwS/yl47QaKVcAdKw7zz4EVmz q1fJ/WdMGaAotWcqHoIHHXPHLtdiy/7yZVbRbS4ANYlDvQisIKNBm9DwrtTwIi3B3Y3G tsmONvfHUM1OjVk0iy/8yYkTBdutooHri9VZGqIDm+koUB1av6exfd4/dcc8KgoBrCtY 9RFPU9u0QOpYEb9eHoXe0rHswCqYzg+BrHRZ8Yj/GZj2fQanlSUnVf7OBDngoKqq4Tks KkQw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id c11si6381823edj.331.2021.02.08.08.28.15; Mon, 08 Feb 2021 08:28:39 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233358AbhBHQ1Z (ORCPT + 99 others); Mon, 8 Feb 2021 11:27:25 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:7054 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233150AbhBHPLL (ORCPT ); Mon, 8 Feb 2021 10:11:11 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DZ8bG4kdjz9vBnC; Mon, 8 Feb 2021 16:10:18 +0100 (CET) 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 C7rjuJzjDpqL; Mon, 8 Feb 2021 16:10:18 +0100 (CET) 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 4DZ8bG3zSvz9vBn3; Mon, 8 Feb 2021 16:10:18 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C624D8B7B3; Mon, 8 Feb 2021 16:10:23 +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 VNxVEJ7nY3Ry; Mon, 8 Feb 2021 16:10:23 +0100 (CET) Received: from po16121vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.103]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 8AD4A8B7B2; Mon, 8 Feb 2021 16:10:23 +0100 (CET) Received: by po16121vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 800A56733E; Mon, 8 Feb 2021 15:10:23 +0000 (UTC) Message-Id: <8fa13a59f73647e058c95fc7e1c7a98f316bd20a.1612796617.git.christophe.leroy@csgroup.eu> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v5 04/22] powerpc/32: Reorder instructions to avoid using CTR in syscall entry To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , npiggin@gmail.com, msuchanek@suse.de Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Mon, 8 Feb 2021 15:10:23 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that we are using rfi instead of mtmsr to reactivate MMU, it is possible to reorder instructions and avoid the need to use CTR for stashing SRR0. null_syscall on 8xx is reduced by 3 cycles (283 => 280 cycles). Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/head_32.h | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h index 4029c51dce5d..24dc326e0d56 100644 --- a/arch/powerpc/kernel/head_32.h +++ b/arch/powerpc/kernel/head_32.h @@ -116,30 +116,28 @@ .endm .macro SYSCALL_ENTRY trapno - mfspr r12,SPRN_SPRG_THREAD mfspr r9, SPRN_SRR1 - mfspr r11, SPRN_SRR0 - mtctr r11 + mfspr r10, SPRN_SRR0 andi. r11, r9, MSR_PR + beq- 99f + LOAD_REG_IMMEDIATE(r11, MSR_KERNEL) /* can take exceptions */ + lis r12, 1f@h + ori r12, r12, 1f@l + mtspr SPRN_SRR1, r11 + mtspr SPRN_SRR0, r12 + mfspr r12,SPRN_SPRG_THREAD mr r11, r1 lwz r1,TASK_STACK-THREAD(r12) - beq- 99f + tovirt(r12, r12) addi r1, r1, THREAD_SIZE - INT_FRAME_SIZE - LOAD_REG_IMMEDIATE(r10, MSR_KERNEL) /* can take exceptions */ - mtspr SPRN_SRR1, r10 - lis r10, 1f@h - ori r10, r10, 1f@l - mtspr SPRN_SRR0, r10 rfi 1: - tovirt(r12, r12) stw r11,GPR1(r1) stw r11,0(r1) mr r11, r1 + stw r10,_NIP(r11) mflr r10 stw r10, _LINK(r11) - mfctr r10 - stw r10,_NIP(r11) mfcr r10 rlwinm r10,r10,0,4,2 /* Clear SO bit in CR */ stw r10,_CCR(r11) /* save registers */ -- 2.25.0