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=-8.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 5661AC433E2 for ; Tue, 8 Sep 2020 07:42:25 +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 0EC5021D43 for ; Tue, 8 Sep 2020 07:42:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="lxuQHTYt"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Yk9PkO9d" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0EC5021D43 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.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-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=QsaF89rxfkkUp9Na9tqNNq0NnqApL1R446ZKQQfaLnQ=; b=lxuQHTYt8b5vjCteBRqa7xqJy a6PQH0/nMp+yiBPttSiH5Z6Ev7+prv9umArCSDpQoU80rqMcNsb9TGSwtDNpOKL1ZyTLk8r3ytRjw mbOlW7V9IZOsWqsN5yUl6ENwsPK6BDmXGlX24oRsM982oVJ8RLjOiBUtb9F5Yvfb8j3w4RO3fngKp fCI0itfaUQoULxwqu5/+G62FmftdM9Wr0tsxAm9dnJKs+mDaOQYcg4yUTF5O/1Bb+aTTTY+BSq14N NjDfzXjY9KgPiXZAx+pyhFmflIjLJht8Bv2q7FkmQ1ElVbMpMxMz+dVPlY4zwlj9PqmAAWCXieJRI l8awbL//g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFYFb-0004c2-HQ; Tue, 08 Sep 2020 07:41:11 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFYFX-0004al-Cl for linux-arm-kernel@lists.infradead.org; Tue, 08 Sep 2020 07:41:08 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ABF38207DE; Tue, 8 Sep 2020 07:41:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599550866; bh=HTbDPhhePrx7meKqId4XnNwYNA7wvgf4cur7UXe6wDs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Yk9PkO9dwh3d2tWu05VGc6SBTpmH37UUCA8ABHP6QImgn9uajeHngR11YELACxXv3 D/tNw6Vuo5c1lg4ICa6WfPMWcXOHhI7kwFm+OIpnCUPSQBJPfYafxsN6KHSM/JOKt3 lDsUB94GcBKoNWGsak8uFqAZY8y1ojUgid+bMenA= Date: Tue, 8 Sep 2020 08:41:01 +0100 From: Will Deacon To: Anshuman Khandual Subject: Re: [PATCH V3] arm64/cpuinfo: Define HWCAP name arrays per their actual bit definitions Message-ID: <20200908074059.GA14790@willie-the-truck> References: <1597665863-564-1-git-send-email-anshuman.khandual@arm.com> <20200907121611.GA12237@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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-20200908_034107_578450_0D62505E X-CRM114-Status: GOOD ( 27.87 ) 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: Mark Rutland , Suzuki K Poulose , catalin.marinas@arm.com, linux-kernel@vger.kernel.org, Ard Biesheuvel , Mark Brown , Dave Martin , 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+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Sep 08, 2020 at 10:43:12AM +0530, Anshuman Khandual wrote: > > > On 09/07/2020 05:46 PM, Will Deacon wrote: > > On Mon, Aug 17, 2020 at 05:34:23PM +0530, Anshuman Khandual wrote: > >> HWCAP name arrays (hwcap_str, compat_hwcap_str, compat_hwcap2_str) that are > >> scanned for /proc/cpuinfo are detached from their bit definitions making it > >> vulnerable and difficult to correlate. It is also bit problematic because > >> during /proc/cpuinfo dump these arrays get traversed sequentially assuming > >> they reflect and match actual HWCAP bit sequence, to test various features > >> for a given CPU. This redefines name arrays per their HWCAP bit definitions > >> . It also warns after detecting any feature which is not expected on arm64. > >> > >> Cc: Catalin Marinas > >> Cc: Will Deacon > >> Cc: Mark Brown > >> Cc: Dave Martin > >> Cc: Ard Biesheuvel > >> Cc: Mark Rutland > >> Cc: Suzuki K Poulose > >> Cc: linux-arm-kernel@lists.infradead.org > >> Cc: linux-kernel@vger.kernel.org > >> Signed-off-by: Anshuman Khandual > >> --- > >> This applies on 5.9-rc1 > >> > >> Mark, since the patch has changed I have dropped your Acked-by: tag. Are you > >> happy to give a new one ? > >> > >> Changes in V3: > >> > >> - Moved name arrays to (arch/arm64/kernel/cpuinfo.c) to prevent a build warning > >> - Replaced string values with NULL for all compat features not possible on arm64 > >> - Changed compat_hwcap_str[] iteration on size as some NULL values are expected > >> - Warn once after detecting any feature on arm64 that is not expected > >> > >> Changes in V2: (https://patchwork.kernel.org/patch/11533755/) > >> > >> - Defined COMPAT_KERNEL_HWCAP[2] and updated the name arrays per Mark > >> - Updated the commit message as required > >> > >> Changes in V1: (https://patchwork.kernel.org/patch/11532945/) > >> > >> arch/arm64/include/asm/hwcap.h | 9 +++ > >> arch/arm64/kernel/cpuinfo.c | 172 ++++++++++++++++++++++------------------- > >> 2 files changed, 100 insertions(+), 81 deletions(-) > > > > [...] > > > >> + [KERNEL_HWCAP_FP] = "fp", > >> + [KERNEL_HWCAP_ASIMD] = "asimd", > >> + [KERNEL_HWCAP_EVTSTRM] = "evtstrm", > >> + [KERNEL_HWCAP_AES] = "aes", > > > > It would be nice if the cap and the string were generated by the same > > macro, along the lines of: > > > > #define KERNEL_HWCAP(c) [KERNEL_HWCAP_##c] = #c, > > > > Does making the constants mixed case break anything, or is it just really > > churny to do? > > Currently all existing HWCAP feature strings are lower case, above change > will make them into upper case instead. I could not find a method to force > convert #c into lower case constant strings in the macro definition. Would > not changing the HWCAP string case here, break user interface ? Yes, we can't change the user-visible strings, but what's wrong with having e.g. KERNEL_HWCAP_fp instead of KERNEL_HWCAP_FP? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel