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=-5.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_MUTT 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 C5D1BC28CC6 for ; Tue, 4 Jun 2019 13:49:12 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 8488023CEB for ; Tue, 4 Jun 2019 13:49:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="G5W2A2kP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8488023CEB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Ju39/slq08B6lIopb1c8pq0LF3eKaJ99XTvnGwsHT3Y=; b=G5W2A2kPe/gaun PoEx5tCEPHUom0DUefSQCNLGjiMoahuSdR5uyDaujFRLwOwhJQQW+SuWd6Mef8V7HSuDD7mFj8GqO k1U5bKcgwMpAm2mssrkU2sjW5glcAiJ01HNbsd5T8lS30GitGhoPMNqd7j+zOvFMN1RHKPqi7zI+w X0QqC+W4OcDzBOWMkmamQcQSnxSjrVT/JlxKrfS8v/keNGc+8hAEhOKPN7yUhGUff2WDLSuGGBsoS XZxpP0y9oCai66BeluQgZ5KbS8yBnaQlHGU/h+4iOUqfqueBwF8EhQ5+fOs2f+HL/pWStVrYRmmYR AU9FrVRfexrz9MfDJhWQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hY9oN-0004y6-FS; Tue, 04 Jun 2019 13:49:11 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hY9oK-0004x9-Cu for linux-arm-kernel@lists.infradead.org; Tue, 04 Jun 2019 13:49:09 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 46D20341; Tue, 4 Jun 2019 06:49:06 -0700 (PDT) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 790F53F690; Tue, 4 Jun 2019 06:49:04 -0700 (PDT) Date: Tue, 4 Jun 2019 14:49:01 +0100 From: Catalin Marinas To: Julien Grall Subject: Re: [PATCH] arm64/cpufeature: Convert hook_lock to raw_spin_lock_t in cpu_enable_ssbs() Message-ID: <20190604134901.GE6610@arrakis.emea.arm.com> References: <20190530113058.1988-1-julien.grall@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190530113058.1988-1-julien.grall@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190604_064908_441057_4C14BDD1 X-CRM114-Status: GOOD ( 12.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-rt-users@vger.kernel.org, suzuki.poulose@arm.com, bigeasy@linutronix.de, will.deacon@arm.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, tglx@linutronix.de, dave.martin@arm.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, May 30, 2019 at 12:30:58PM +0100, Julien Grall wrote: > cpu_enable_ssbs() is called via stop_machine() as part of the cpu_enable > callback. A spin lock is used to ensure the hook is registered before > the rest of the callback is executed. > > On -RT spin_lock() may sleep. However, all the callees in stop_machine() > are expected to not sleep. Therefore a raw_spin_lock() is required here. > > Given this is already done under stop_machine() and the work done under > the lock is quite small, the latency should not increase too much. > > Signed-off-by: Julien Grall Queued for 5.3. Thanks. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel