From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1425668AbdEZIpW (ORCPT ); Fri, 26 May 2017 04:45:22 -0400 Received: from terminus.zytor.com ([65.50.211.136]:38335 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1425631AbdEZIpU (ORCPT ); Fri, 26 May 2017 04:45:20 -0400 Date: Fri, 26 May 2017 01:41:42 -0700 From: tip-bot for Sebastian Andrzej Siewior Message-ID: Cc: mingo@kernel.org, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, rostedt@goodmis.org, hpa@zytor.com, bp@suse.de, bigeasy@linutronix.de, bp@alien8.de, peterz@infradead.org Reply-To: tglx@linutronix.de, rostedt@goodmis.org, bigeasy@linutronix.de, bp@suse.de, hpa@zytor.com, bp@alien8.de, peterz@infradead.org, mingo@kernel.org, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org In-Reply-To: <20170524081548.594862191@linutronix.de> References: <20170524081548.594862191@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:smp/hotplug] perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() Git-Commit-ID: 1ba143a5216fb148211160a0ecc1f8d3f92f06bb X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 1ba143a5216fb148211160a0ecc1f8d3f92f06bb Gitweb: http://git.kernel.org/tip/1ba143a5216fb148211160a0ecc1f8d3f92f06bb Author: Sebastian Andrzej Siewior AuthorDate: Wed, 24 May 2017 10:15:30 +0200 Committer: Thomas Gleixner CommitDate: Fri, 26 May 2017 10:10:43 +0200 perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() If intel_snb_check_microcode() is invoked via microcode_init -> perf_check_microcode -> intel_snb_check_microcode then get_online_cpus() is invoked nested. This works with the current implementation of get_online_cpus() but prevents converting it to a percpu rwsem. intel_snb_check_microcode() is also invoked from intel_sandybridge_quirk() unprotected. Drop get_online_cpus() from intel_snb_check_microcode() and add it to intel_sandybridge_quirk() so both call sites are protected. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Acked-by: Borislav Petkov Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Borislav Petkov Link: http://lkml.kernel.org/r/20170524081548.594862191@linutronix.de --- arch/x86/events/intel/core.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index a6d91d4..b9174aa 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3410,12 +3410,10 @@ static void intel_snb_check_microcode(void) int pebs_broken = 0; int cpu; - get_online_cpus(); for_each_online_cpu(cpu) { if ((pebs_broken = intel_snb_pebs_broken(cpu))) break; } - put_online_cpus(); if (pebs_broken == x86_pmu.pebs_broken) return; @@ -3488,7 +3486,9 @@ static bool check_msr(unsigned long msr, u64 mask) static __init void intel_sandybridge_quirk(void) { x86_pmu.check_microcode = intel_snb_check_microcode; + cpus_read_lock(); intel_snb_check_microcode(); + cpus_read_unlock(); } static const struct { int id; char *name; } intel_arch_events_map[] __initconst = { @@ -4112,13 +4112,12 @@ static __init int fixup_ht_bug(void) lockup_detector_resume(); - get_online_cpus(); + cpus_read_lock(); - for_each_online_cpu(c) { + for_each_online_cpu(c) free_excl_cntrs(c); - } - put_online_cpus(); + cpus_read_unlock(); pr_info("PMU erratum BJ122, BV98, HSD29 workaround disabled, HT off\n"); return 0; }