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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 17FAAC433E0 for ; Tue, 11 Aug 2020 04:49:38 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D913420678 for ; Tue, 11 Aug 2020 04:49:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="egaQ9OIj"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="e/4M4rWo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D913420678 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1dQIRkpxiv5pYqVCs92YtOCN41HIUJYdLdqbLGJwsn0=; b=egaQ9OIj6Fl48SJ3JGyCU02lw elf1kFftZz5ksoG8ijTc1TUKPZIZy+AE+kjk6/kHrRVrIiEbkoAIaCKLjuEj9NW1Odpdg8pQ22JLH xL1f8tDtQH1jgrejYQoO3pwnJIQ0NDW+DBxn+mppRekGRqV09J9/UyNz962abakJU3uToxyaws9f4 WTzHo4zDoX/qgWHnV9VYNNFI6GSWaEvAIxY7kYxnABOwUp7MCtDTfk8RFHIxFTlW0DMw2sD6+ZDM7 z2EipXfRIdo/vKytYRRvF2Pj89mjVYbA4wWiDS7KHIjnKqXwAFW71ip3VsXOHMBSBowNukOVM4//W 31utgCP3w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k5MD1-0005B8-Fq; Tue, 11 Aug 2020 04:48:23 +0000 Received: from mail29.static.mailgun.info ([104.130.122.29]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k5MCz-0005Ah-5r for linux-arm-kernel@lists.infradead.org; Tue, 11 Aug 2020 04:48:22 +0000 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1597121300; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=0cJt+WgRXB1nbIu2m8++kElnkIQWCS3PK5eceIKAvUk=; b=e/4M4rWo5TDF3m2PFEe1PWy7rsUZZ8dtdMb0uyvMlpWfrWc810/WplVqM8dwv4hiNzTWTSjs D9q5jGgGzHacMQUrJO1J6cqCn/auF39z0deBY3UemWF4prqX+ijlGxZxlnCVOAoralAyNDoD 0GWcXY9I2J6+rxqC1HFx/dKUp6k= X-Mailgun-Sending-Ip: 104.130.122.29 X-Mailgun-Sid: WyJiYzAxZiIsICJsaW51eC1hcm0ta2VybmVsQGxpc3RzLmluZnJhZGVhZC5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n01.prod.us-east-1.postgun.com with SMTP id 5f322313247ccc308ce67ca9 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Tue, 11 Aug 2020 04:48:19 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id D42C1C433CB; Tue, 11 Aug 2020 04:48:18 +0000 (UTC) Received: from [192.168.1.4] (unknown [122.170.228.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: gkohli) by smtp.codeaurora.org (Postfix) with ESMTPSA id 2B6E8C433C9; Tue, 11 Aug 2020 04:48:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 2B6E8C433C9 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=gkohli@codeaurora.org Subject: Re: [PATCH] arm64: Skip apply SSBS call for non SSBS system To: will@kernel.org, linux-arm-kernel@lists.infradead.org, maz@kernel.org, Catalin Marinas References: <1596550484-11029-1-git-send-email-gkohli@codeaurora.org> From: Gaurav Kohli Message-ID: <16e9b436-5919-39df-3f1a-a717d4229651@codeaurora.org> Date: Tue, 11 Aug 2020 10:18:13 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <1596550484-11029-1-git-send-email-gkohli@codeaurora.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200811_004821_339661_6D1B0A3F X-CRM114-Status: GOOD ( 21.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, neeraju@codeaurora.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, Please let us know, is below patch good to have or not for non ssbs systems. On 8/4/2020 7:44 PM, Gaurav Kohli wrote: > In a system where no cpu's implement SSBS, for > them no need to set pstate. This might help to save > few cpu cycles during context switch. > > Signed-off-by: Gaurav Kohli > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 6089638..79f80f1 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -477,6 +477,13 @@ static void ssbs_thread_switch(struct task_struct *next) > struct pt_regs *regs = task_pt_regs(next); > > /* > + * For Targets which don't have SSBS support, they > + * can return from here. > + */ > + if (!IS_ENABLED(CONFIG_ARM64_SSBD)) > + return; > + > + /* > * Nothing to do for kernel threads, but 'regs' may be junk > * (e.g. idle task) so check the flags and bail early. > */ > -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel