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=-15.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 4E932C433DB for ; Tue, 9 Feb 2021 14:32:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F249A64E6C for ; Tue, 9 Feb 2021 14:32:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231319AbhBIOcc (ORCPT ); Tue, 9 Feb 2021 09:32:32 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:31643 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231878AbhBIObw (ORCPT ); Tue, 9 Feb 2021 09:31:52 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DZlgV2BM4z9v4gr; Tue, 9 Feb 2021 15:31:02 +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 bnKYf9L8xKhB; Tue, 9 Feb 2021 15:31:02 +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 4DZlgV18f4z9v4gp; Tue, 9 Feb 2021 15:31:02 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 86B318B7E7; Tue, 9 Feb 2021 15:31:03 +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 oydW9FnggjEP; Tue, 9 Feb 2021 15:31:03 +0100 (CET) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id F22898B764; Tue, 9 Feb 2021 15:31:02 +0100 (CET) Subject: Re: [PATCH v5 18/22] powerpc/syscall: Remove FULL_REGS verification in system_call_exception To: Nicholas Piggin , Benjamin Herrenschmidt , Michael Ellerman , msuchanek@suse.de, Paul Mackerras Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org References: <6bef4d9ba0cba50160d13e344ee4627ebdf801dc.1612796617.git.christophe.leroy@csgroup.eu> <1612836023.l122pe2n2b.astroid@bobo.none> From: Christophe Leroy Message-ID: Date: Tue, 9 Feb 2021 15:31:02 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <1612836023.l122pe2n2b.astroid@bobo.none> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 09/02/2021 à 03:02, Nicholas Piggin a écrit : > Excerpts from Christophe Leroy's message of February 9, 2021 1:10 am: >> For book3s/64, FULL_REGS() is 'true' at all time, so the test voids. >> For others, non volatile registers are saved inconditionally. >> >> So the verification is pointless. >> >> Should one fail to do it, it would anyway be caught by the >> CHECK_FULL_REGS() in copy_thread() as we have removed the >> special versions ppc_fork() and friends. >> >> null_syscall benchmark reduction 4 cycles (332 => 328 cycles) > > I wonder if we rather make a CONFIG option for a bunch of these simpler > debug checks here (and also in interrupt exit, wrappers, etc) rather > than remove them entirely. We can drop this patch if you prefer. Anyway, like book3s/64, once ppc32 also do interrupt entry/exit in C, FULL_REGS() will already return true. Christophe > > Thanks, > Nick > >> >> Signed-off-by: Christophe Leroy >> --- >> arch/powerpc/kernel/interrupt.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c >> index 8fafca727b8b..55e1aa18cdb9 100644 >> --- a/arch/powerpc/kernel/interrupt.c >> +++ b/arch/powerpc/kernel/interrupt.c >> @@ -42,7 +42,6 @@ notrace long system_call_exception(long r3, long r4, long r5, >> if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x)) >> BUG_ON(!(regs->msr & MSR_RI)); >> BUG_ON(!(regs->msr & MSR_PR)); >> - BUG_ON(!FULL_REGS(regs)); >> BUG_ON(arch_irq_disabled_regs(regs)); >> >> #ifdef CONFIG_PPC_PKEY >> -- >> 2.25.0 >> >> 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=-15.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 9ADB5C433DB for ; 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Wed, 10 Feb 2021 01:31:07 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DZlgV2BM4z9v4gr; Tue, 9 Feb 2021 15:31:02 +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 bnKYf9L8xKhB; Tue, 9 Feb 2021 15:31:02 +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 4DZlgV18f4z9v4gp; Tue, 9 Feb 2021 15:31:02 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 86B318B7E7; Tue, 9 Feb 2021 15:31:03 +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 oydW9FnggjEP; Tue, 9 Feb 2021 15:31:03 +0100 (CET) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id F22898B764; Tue, 9 Feb 2021 15:31:02 +0100 (CET) Subject: Re: [PATCH v5 18/22] powerpc/syscall: Remove FULL_REGS verification in system_call_exception To: Nicholas Piggin , Benjamin Herrenschmidt , Michael Ellerman , msuchanek@suse.de, Paul Mackerras References: <6bef4d9ba0cba50160d13e344ee4627ebdf801dc.1612796617.git.christophe.leroy@csgroup.eu> <1612836023.l122pe2n2b.astroid@bobo.none> From: Christophe Leroy Message-ID: Date: Tue, 9 Feb 2021 15:31:02 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <1612836023.l122pe2n2b.astroid@bobo.none> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit 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+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Le 09/02/2021 à 03:02, Nicholas Piggin a écrit : > Excerpts from Christophe Leroy's message of February 9, 2021 1:10 am: >> For book3s/64, FULL_REGS() is 'true' at all time, so the test voids. >> For others, non volatile registers are saved inconditionally. >> >> So the verification is pointless. >> >> Should one fail to do it, it would anyway be caught by the >> CHECK_FULL_REGS() in copy_thread() as we have removed the >> special versions ppc_fork() and friends. >> >> null_syscall benchmark reduction 4 cycles (332 => 328 cycles) > > I wonder if we rather make a CONFIG option for a bunch of these simpler > debug checks here (and also in interrupt exit, wrappers, etc) rather > than remove them entirely. We can drop this patch if you prefer. Anyway, like book3s/64, once ppc32 also do interrupt entry/exit in C, FULL_REGS() will already return true. Christophe > > Thanks, > Nick > >> >> Signed-off-by: Christophe Leroy >> --- >> arch/powerpc/kernel/interrupt.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c >> index 8fafca727b8b..55e1aa18cdb9 100644 >> --- a/arch/powerpc/kernel/interrupt.c >> +++ b/arch/powerpc/kernel/interrupt.c >> @@ -42,7 +42,6 @@ notrace long system_call_exception(long r3, long r4, long r5, >> if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x)) >> BUG_ON(!(regs->msr & MSR_RI)); >> BUG_ON(!(regs->msr & MSR_PR)); >> - BUG_ON(!FULL_REGS(regs)); >> BUG_ON(arch_irq_disabled_regs(regs)); >> >> #ifdef CONFIG_PPC_PKEY >> -- >> 2.25.0 >> >>