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=-5.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 13D62C43331 for ; Fri, 6 Sep 2019 13:49:51 +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 DBED8206B8 for ; Fri, 6 Sep 2019 13:49:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="j6g2XDbu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DBED8206B8 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=CFF1SuaI0j5s7/P4uwZMwcjmagjXLpVdI51gtmNKIQs=; b=j6g2XDbugjM5Gp cuHxsKkcMkWLpT/3U1yKRI9+AlZ3wmIngaxiTUns65e0+SYiwK1aAicFSyj7Evg9x3jz6ANOZlbp3 /v8uoGB/zmo9Y7rfhXHM2GHT90TvhQtA1ShGfP+nHN3O8zPYEA67rFjghFIs8Gj22HAS+LBsj60Ji zQ+aK7BuYpdCxqXVw3cmcWTlQmYO2Cig6+7QmwqeDiup0r5mmP1nR2XRoVJFGeXC7BF4yPH73zT6n uORh6uTRVkgkJ0Byh4fQECjgh8hKQ4pNxNoSVhjib8d6XZRjhku0NZc+dnMdkU2XCVxAGgeslKc+X jxNRUN2jBLT6jUbh+FNw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i6EcW-00056M-ME; Fri, 06 Sep 2019 13:49:48 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i6EcT-00055v-LX for linux-arm-kernel@lists.infradead.org; Fri, 06 Sep 2019 13:49:47 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8C02B28; Fri, 6 Sep 2019 06:49:43 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3846B3F718; Fri, 6 Sep 2019 06:49:42 -0700 (PDT) Date: Fri, 6 Sep 2019 14:49:35 +0100 From: Mark Rutland To: Viresh Kumar Subject: Re: [PATCH ARM64 v4.4 V3 12/44] arm64: cpufeature: Test 'matches' pointer to find the end of the list Message-ID: <20190906134935.GA17375@lakrids.cambridge.arm.com> References: <617ad445043f040c5ab986b9620b2ba7847b561e.1567077734.git.viresh.kumar@linaro.org> <20190902142741.GB9922@lakrids.cambridge.arm.com> <20190905074506.oxsw24xoex7gcfgm@vireshk-i7> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190905074506.oxsw24xoex7gcfgm@vireshk-i7> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190906_064945_794791_A9CD7995 X-CRM114-Status: GOOD ( 33.06 ) 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: Julien Thierry , Marc Zyngier , Catalin Marinas , Will Deacon , stable@vger.kernel.org, mark.brown@arm.com, Russell King , 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, Sep 05, 2019 at 01:15:06PM +0530, Viresh Kumar wrote: > On 02-09-19, 15:27, Mark Rutland wrote: > > On Thu, Aug 29, 2019 at 05:03:57PM +0530, Viresh Kumar wrote: > > > From: James Morse > > > > > > commit 644c2ae198412c956700e55a2acf80b2541f6aa5 upstream. > > > > > > CPU feature code uses the desc field as a test to find the end of the list, > > > this means every entry must have a description. This generates noise for > > > entries in the list that aren't really features, but combinations of them. > > > e.g. > > > > CPU features: detected feature: Privileged Access Never > > > > CPU features: detected feature: PAN and not UAO > > > > > > These combination features are needed for corner cases with alternatives, > > > where cpu features interact. > > > > > > Change all walkers of the arm64_features[] and arm64_hwcaps[] lists to test > > > 'matches' not 'desc', and only print 'desc' if it is non-NULL. > > > > > > Signed-off-by: James Morse > > > Reviewed-by : Suzuki K Poulose > > > Signed-off-by: Catalin Marinas > > > Signed-off-by: Viresh Kumar > > > --- > > > arch/arm64/kernel/cpufeature.c | 12 ++++++------ > > > 1 file changed, 6 insertions(+), 6 deletions(-) > > > > >From looking at my 4.9.y/{meltdown,spectre} banches on kernel.org [1,2], > > and chasing the history v4.4..v4.9, there are a number of patches I'd > > expect to have alongside this that I don't spot in this series: > > > > * e3661b128e53ee281e1e7c589a5b647890bd6d7c ("arm64: Allow a capability to be checked on a single CPU") > > * 8f4137588261d7504f4aa022dc9d1a1fd1940e8e ("arm64: Allow checking of a CPU-local erratum") > > * 67948af41f2e6818edeeba5182811c704d484949 ("arm64: capabilities: Handle duplicate entries for a capability") > > * edf298cfce47ab7279d03b5203ae2ef3a58e49db ("arm64: cpufeature: __this_cpu_has_cap() shouldn't stop early") > > I also had to pick this one for cleaner rebase: > > 752835019c15 arm64: HWCAP: Split COMPAT HWCAP table entries > > > > > ... which IIUC are necessary for big.LITTLE to work correctly. > > I have pushed the changes to my branch again with above 5 patches and > some more reordering to match 4.9 log. Thanks for this! > > Have you verified this for big.LITTLE? > > Not sure if we ever talked about this earlier, but here is the > situation which I explained to Julien earlier. > > I don't have access to the test-suite to verify that these patches > indeed fix the spectre mitigations and I was asked to backport these > and then ask for help from ARM to get these tested through the > test-suite. I was expecting Julien to do that earlier. Ok, thanks for providing this context. As a heads-up, I'll be at LPC next week. While I'm there I won't be able to test things, and I'm unlikely to find time to review, but I'll try to do so ASAP once I return. > Julien did ask me to verify few things earlier, which can be done > without the test suite and was about checking that the new code paths > are getting hit now or not, which I did. > > I haven't tested these on big LITTLE, though I can get the branch > through LAVA to get it tested on big LITTLE but I have no clue on what > I should be looking for in results :) I think it would be worthwhile to do that ASAP to make sure there are no boot-time or run-time regressions. We can look at the logs later (or re-run with some additional logging) to verify things are working as expected. > If there is some testing that can be done on my side for this, I sure > can do it. But I would need help from you on that to know what exactly > I need to check. Sure. I'll have to take another look over the series to figure that out, and as above I might not be able to do so until after LPC -- sorry! Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel