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=-8.6 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=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 04F84C2D0E2 for ; Mon, 7 Sep 2020 12:17:54 +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 3A7822075A for ; Mon, 7 Sep 2020 12:17:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Q7sZn33V"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ibqdHTlW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A7822075A 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=96UF5cdbNKFpve0SyfbyErkSpl9NDt14Vg58JRs+w00=; b=Q7sZn33VE9wgI4fO8kw4xj9fa WdSCwbH6txyhRiQEDKcEiIg9u6MudM07OV3vz6nTIIbbekgrJFIzSb4bRQ5u8SxIP+cN3O2gHO4T4 Oipofy8BM/m/7v5en2FWMnzkVMrEGo1ysMrnIN7hMvFs4YRjIBHlX3W0gCp9yFY0ztQt3sxENGFaf bu7cNw9BeAcFZ80HsrFvuKSwK0675/B+NhNOlbhEajpTU/8hMVTUSMQX/LXRsgyde75Wxw/qyMeDF UiJkTDcnu/RLEunUc/oD1RX8Hz3Ls3ctTwFQCFEWaryWjEpEeZcFmE5ZgG5K6/z+ZJdc1k7bQUuqn QszBucdwQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFG4K-0006iI-Ip; Mon, 07 Sep 2020 12:16:20 +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 1kFG4I-0006hx-2f for linux-arm-kernel@lists.infradead.org; Mon, 07 Sep 2020 12:16:19 +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 668222075A; Mon, 7 Sep 2020 12:16:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599480976; bh=rVo9sIaJfmCRWE4FoqnLmL1YvT7fJE04BXGXALFvavQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ibqdHTlWtj8fVzuAtUTJF7iep0nyxxqaeZ5d6wNHyTSBujcUgQoVz08GsIsjBP/9Y T5tDzKWcs0FAHofEwjeqtMzrri3PUciAziZOBt1P6DkfEjgVBI5Lfn2oqfEHnTTPqP 3esz4w8eF6Q3S+cCMrSedn6CBYjF6nL0N5uwZ9+A= Date: Mon, 7 Sep 2020 13:16:12 +0100 From: Will Deacon To: Anshuman Khandual Subject: Re: [PATCH V3] arm64/cpuinfo: Define HWCAP name arrays per their actual bit definitions Message-ID: <20200907121611.GA12237@willie-the-truck> References: <1597665863-564-1-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1597665863-564-1-git-send-email-anshuman.khandual@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-20200907_081618_244065_D18645E7 X-CRM114-Status: GOOD ( 26.43 ) 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 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? > @@ -166,9 +167,18 @@ static int c_show(struct seq_file *m, void *v) > seq_puts(m, "Features\t:"); > if (compat) { > #ifdef CONFIG_COMPAT > - for (j = 0; compat_hwcap_str[j]; j++) > - if (compat_elf_hwcap & (1 << j)) > + for (j = 0; j < ARRAY_SIZE(compat_hwcap_str); j++) { > + if (compat_elf_hwcap & (1 << j)) { > + /* > + * Warn once if any feature should not > + * have been present on arm64 platform. > + */ > + if (WARN_ON_ONCE(!compat_hwcap_str[j])) > + continue; > + > seq_printf(m, " %s", compat_hwcap_str[j]); > + } > + } > > for (j = 0; compat_hwcap2_str[j]; j++) Hmm, I find this pretty confusing now as compat_hwcap_str is not NULL terminated and must be traversed with a loop bounded by ARRAY_SIZE(...), whereas compat_hwcap2_str *is* NULL terminated and is traversed until you hit the sentinel. I think hwcap_str, compat_hwcap_str and compat_hwcap2_str should be identical in this regard. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel