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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 460FFC3A5A8 for ; Wed, 4 Sep 2019 15:59:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1FDA32087E for ; Wed, 4 Sep 2019 15:59:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567612799; bh=gZSnvrdLULxwjHSAUZkDCTpkQxwg/SW7rI52snceEtM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1Yk5DkD98ZJvgL1ojgPQeR5F47eqIiJxW+N/uOKz3MhfyVWbDAB3JFoG2t5KWoXeK aOL82pW035UG5lNiBYkzM4g6zrljahrcpKMDJWKTQd9yV63cMkz9sY2rBTe0NaaGGx a1ajaw/RFwPjPwKfyDLr/U1L2LqeiCYLTizjJeME= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731785AbfIDP74 (ORCPT ); Wed, 4 Sep 2019 11:59:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:34306 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732465AbfIDP7o (ORCPT ); Wed, 4 Sep 2019 11:59:44 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B94CD20820; Wed, 4 Sep 2019 15:59:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567612783; bh=gZSnvrdLULxwjHSAUZkDCTpkQxwg/SW7rI52snceEtM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BnKu8VcSp3lxODEFAdEQ8tvfBPM/mMgdgDMwgrcxlJ/nfO/C9x7t3d1fJOdS8TfJ+ jA96yYwCl5QC3iXppgPvni4+5EAL5Ki1m7U84y8sxWrFWJReY3V/4P023ZkLVFkuM/ JCvmeHaroolavxbBzEQW5vqAHS8F63UMn4djnRek= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ben Hutchings , Len Brown , Sasha Levin Subject: [PATCH AUTOSEL 5.2 79/94] tools/power x86_energy_perf_policy: Fix "uninitialized variable" warnings at -O2 Date: Wed, 4 Sep 2019 11:57:24 -0400 Message-Id: <20190904155739.2816-79-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190904155739.2816-1-sashal@kernel.org> References: <20190904155739.2816-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ben Hutchings [ Upstream commit adb8049097a9ec4acd09fbd3aa8636199a78df8a ] x86_energy_perf_policy first uses __get_cpuid() to check the maximum CPUID level and exits if it is too low. It then assumes that later calls will succeed (which I think is architecturally guaranteed). It also assumes that CPUID works at all (which is not guaranteed on x86_32). If optimisations are enabled, gcc warns about potentially uninitialized variables. Fix this by adding an exit-on-error after every call to __get_cpuid() instead of just checking the maximum level. Signed-off-by: Ben Hutchings Signed-off-by: Len Brown Signed-off-by: Sasha Levin --- .../x86_energy_perf_policy.c | 26 +++++++++++-------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c index 34a796b303fe2..7663abef51e96 100644 --- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c +++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c @@ -1259,6 +1259,15 @@ void probe_dev_msr(void) if (system("/sbin/modprobe msr > /dev/null 2>&1")) err(-5, "no /dev/cpu/0/msr, Try \"# modprobe msr\" "); } + +static void get_cpuid_or_exit(unsigned int leaf, + unsigned int *eax, unsigned int *ebx, + unsigned int *ecx, unsigned int *edx) +{ + if (!__get_cpuid(leaf, eax, ebx, ecx, edx)) + errx(1, "Processor not supported\n"); +} + /* * early_cpuid() * initialize turbo_is_enabled, has_hwp, has_epb @@ -1266,15 +1275,10 @@ void probe_dev_msr(void) */ void early_cpuid(void) { - unsigned int eax, ebx, ecx, edx, max_level; + unsigned int eax, ebx, ecx, edx; unsigned int fms, family, model; - __get_cpuid(0, &max_level, &ebx, &ecx, &edx); - - if (max_level < 6) - errx(1, "Processor not supported\n"); - - __get_cpuid(1, &fms, &ebx, &ecx, &edx); + get_cpuid_or_exit(1, &fms, &ebx, &ecx, &edx); family = (fms >> 8) & 0xf; model = (fms >> 4) & 0xf; if (family == 6 || family == 0xf) @@ -1288,7 +1292,7 @@ void early_cpuid(void) bdx_highest_ratio = msr & 0xFF; } - __get_cpuid(0x6, &eax, &ebx, &ecx, &edx); + get_cpuid_or_exit(0x6, &eax, &ebx, &ecx, &edx); turbo_is_enabled = (eax >> 1) & 1; has_hwp = (eax >> 7) & 1; has_epb = (ecx >> 3) & 1; @@ -1306,7 +1310,7 @@ void parse_cpuid(void) eax = ebx = ecx = edx = 0; - __get_cpuid(0, &max_level, &ebx, &ecx, &edx); + get_cpuid_or_exit(0, &max_level, &ebx, &ecx, &edx); if (ebx == 0x756e6547 && edx == 0x49656e69 && ecx == 0x6c65746e) genuine_intel = 1; @@ -1315,7 +1319,7 @@ void parse_cpuid(void) fprintf(stderr, "CPUID(0): %.4s%.4s%.4s ", (char *)&ebx, (char *)&edx, (char *)&ecx); - __get_cpuid(1, &fms, &ebx, &ecx, &edx); + get_cpuid_or_exit(1, &fms, &ebx, &ecx, &edx); family = (fms >> 8) & 0xf; model = (fms >> 4) & 0xf; stepping = fms & 0xf; @@ -1340,7 +1344,7 @@ void parse_cpuid(void) errx(1, "CPUID: no MSR"); - __get_cpuid(0x6, &eax, &ebx, &ecx, &edx); + get_cpuid_or_exit(0x6, &eax, &ebx, &ecx, &edx); /* turbo_is_enabled already set */ /* has_hwp already set */ has_hwp_notify = eax & (1 << 8); -- 2.20.1