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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS 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 4F0BEC43381 for ; Fri, 22 Feb 2019 10:21:15 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 F153720823 for ; Fri, 22 Feb 2019 10:21:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F153720823 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 445S6d19rbzDqPj for ; Fri, 22 Feb 2019 21:21:13 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 445RN84PmXzDq7W for ; Fri, 22 Feb 2019 20:47:52 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 445RN8200mz9s9y; Fri, 22 Feb 2019 20:47:51 +1100 (AEDT) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 8cfaf106918a8c13abb24c641556172afbb9545c X-Patchwork-Hint: ignore In-Reply-To: <20190211002002.26038-1-andrew.donnellan@au1.ibm.com> To: Andrew Donnellan , linuxppc-dev@lists.ozlabs.org From: Michael Ellerman Subject: Re: [v2, 1/2] powerpc/64s: Fix logic when handling unknown CPU features Message-Id: <445RN8200mz9s9y@ozlabs.org> Date: Fri, 22 Feb 2019 20:47:51 +1100 (AEDT) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: syzkaller@googlegroups.com, dvyukov@google.com, npiggin@gmail.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, 2019-02-11 at 00:20:01 UTC, Andrew Donnellan wrote: > From: Michael Ellerman > > In cpufeatures_process_feature(), if a provided CPU feature is unknown and > enable_unknown is false, we erroneously print that the feature is being > enabled and return true, even though no feature has been enabled, and > may also set feature bits based on the last entry in the match table. > > Fix this so that we only set feature bits from the match table if we have > actually enabled a feature from that table, and when failing to enable an > unknown feature, always print the "not enabling" message and return false. > > Coincidentally, some older gccs ( -fsanitize-coverage=trace-pc, cause a spurious uninitialised variable > warning in this function: > > arch/powerpc/kernel/dt_cpu_ftrs.c: In function ‘cpufeatures_process_feature’: > arch/powerpc/kernel/dt_cpu_ftrs.c:686:7: warning: ‘m’ may be used uninitialized in this function [-Wmaybe-uninitialized] > if (m->cpu_ftr_bit_mask) > > An upcoming patch will enable support for kcov, which requires this option. > This patch avoids the warning. > > Fixes: 5a61ef74f269 ("powerpc/64s: Support new device tree binding for discovering CPU features") > Reported-by: Segher Boessenkool > Signed-off-by: Michael Ellerman > [ajd: add commit message] > Signed-off-by: Andrew Donnellan Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/8cfaf106918a8c13abb24c641556172a cheers