From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECDBDC433E0 for ; Mon, 25 Jan 2021 15:18:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFD1222C9E for ; Mon, 25 Jan 2021 15:18:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730017AbhAYPS0 (ORCPT ); Mon, 25 Jan 2021 10:18:26 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:23472 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727724AbhAYOvi (ORCPT ); Mon, 25 Jan 2021 09:51:38 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DPXmV1Y4gz9v0Hn; Mon, 25 Jan 2021 15:48:26 +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 Gq9jOa5vgKYf; Mon, 25 Jan 2021 15:48:26 +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 4DPXmV0n9Hz9v0Hk; Mon, 25 Jan 2021 15:48:26 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9512D8B79E; Mon, 25 Jan 2021 15:48:31 +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 ZM_UXbdgvx_U; Mon, 25 Jan 2021 15:48:31 +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 67FD88B79B; Mon, 25 Jan 2021 15:48:31 +0100 (CET) Received: by po16121vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 5BDD866AD8; Mon, 25 Jan 2021 14:48:31 +0000 (UTC) Message-Id: In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v4 18/23] powerpc/32: Remove verification of MSR_PR on syscall in the ASM 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, 25 Jan 2021 14:48:31 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org system_call_exception() checks MSR_PR and BUGs if a syscall is issued from kernel mode. No need to handle it anymore from the ASM entry code. null_syscall reduction 2 cycles (348 => 346 cycles) Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/entry_32.S | 30 ------------------------------ arch/powerpc/kernel/head_32.h | 3 --- arch/powerpc/kernel/head_booke.h | 3 --- 3 files changed, 36 deletions(-) diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index ce5fdb23ed7c..9922a04650f7 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -416,36 +416,6 @@ ret_from_kernel_thread: li r3,0 b ret_from_syscall - /* - * System call was called from kernel. We get here with SRR1 in r9. - * Mark the exception as recoverable once we have retrieved SRR0, - * trap a warning and return ENOSYS with CR[SO] set. - */ - .globl ret_from_kernel_syscall -ret_from_kernel_syscall: - mfspr r9, SPRN_SRR0 - mfspr r10, SPRN_SRR1 -#if !defined(CONFIG_4xx) && !defined(CONFIG_BOOKE) - LOAD_REG_IMMEDIATE(r11, MSR_KERNEL & ~(MSR_IR|MSR_DR)) - mtmsr r11 -#endif - -0: trap - EMIT_BUG_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING - - li r3, ENOSYS - crset so -#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) - mtspr SPRN_NRI, r0 -#endif - mtspr SPRN_SRR0, r9 - mtspr SPRN_SRR1, r10 - rfi -#ifdef CONFIG_40x - b . /* Prevent prefetch past rfi */ -#endif -_ASM_NOKPROBE_SYMBOL(ret_from_kernel_syscall) - /* * Top-level page fault handling. * This is in assembler because if do_page_fault tells us that diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h index c2aa0d8f1f63..c0de4acbe3f8 100644 --- a/arch/powerpc/kernel/head_32.h +++ b/arch/powerpc/kernel/head_32.h @@ -118,8 +118,6 @@ .macro SYSCALL_ENTRY trapno mfspr r9, SPRN_SRR1 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 @@ -176,7 +174,6 @@ 3: #endif b transfer_to_syscall /* jump to handler */ -99: b ret_from_kernel_syscall .endm .macro save_dar_dsisr_on_stack reg1, reg2, sp diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h index faff094b650e..7af84e1e717b 100644 --- a/arch/powerpc/kernel/head_booke.h +++ b/arch/powerpc/kernel/head_booke.h @@ -106,10 +106,8 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV) #endif mfspr r9, SPRN_SRR1 BOOKE_CLEAR_BTB(r11) - andi. r11, r9, MSR_PR lwz r11, TASK_STACK - THREAD(r10) rlwinm r12,r12,0,4,2 /* Clear SO bit in CR */ - beq- 99f ALLOC_STACK_FRAME(r11, THREAD_SIZE - INT_FRAME_SIZE) stw r12, _CCR(r11) /* save various registers */ mflr r12 @@ -157,7 +155,6 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV) 3: b transfer_to_syscall /* jump to handler */ -99: b ret_from_kernel_syscall .endm /* To handle the additional exception priority levels on 40x and Book-E -- 2.25.0