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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 B919CC43381 for ; Wed, 27 Mar 2019 09:58:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8AA842070B for ; Wed, 27 Mar 2019 09:58:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732972AbfC0J6l (ORCPT ); Wed, 27 Mar 2019 05:58:41 -0400 Received: from terminus.zytor.com ([198.137.202.136]:38083 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731668AbfC0J6k (ORCPT ); Wed, 27 Mar 2019 05:58:40 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x2R9wIJi2804316 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Wed, 27 Mar 2019 02:58:18 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x2R9wHCY2804313; Wed, 27 Mar 2019 02:58:17 -0700 Date: Wed, 27 Mar 2019 02:58:17 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Tony Luck Message-ID: Cc: ashok.raj@intel.com, tony.luck@intel.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, Yazen.Ghannam@amd.com, mingo@kernel.org, hpa@zytor.com, x86@kernel.org, bp@suse.de, linux-edac@vger.kernel.org Reply-To: tglx@linutronix.de, mingo@redhat.com, Yazen.Ghannam@amd.com, linux-edac@vger.kernel.org, mingo@kernel.org, ashok.raj@intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tony.luck@intel.com, bp@suse.de, x86@kernel.org In-Reply-To: <20190312170938.GA23035@agluck-desk> References: <20190312170938.GA23035@agluck-desk> To: linux-tip-commits@vger.kernel.org Subject: [tip:ras/core] x86/mce: Fix machine_check_poll() tests for error types Git-Commit-ID: f19501aa07f18268ab14f458b51c1c6b7f72a134 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f19501aa07f18268ab14f458b51c1c6b7f72a134 Gitweb: https://git.kernel.org/tip/f19501aa07f18268ab14f458b51c1c6b7f72a134 Author: Tony Luck AuthorDate: Tue, 12 Mar 2019 10:09:38 -0700 Committer: Borislav Petkov CommitDate: Wed, 27 Mar 2019 10:53:49 +0100 x86/mce: Fix machine_check_poll() tests for error types There has been a lurking "TBD" in the machine check poll routine ever since it was first split out from the machine check handler. The potential issue is that the poll routine may have just begun a read from the STATUS register in a machine check bank when the hardware logs an error in that bank and signals a machine check. That race used to be pretty small back when machine checks were broadcast, but the addition of local machine check means that the poll code could continue running and clear the error from the bank before the local machine check handler on another CPU gets around to reading it. Fix the code to be sure to only process errors that need to be processed in the poll code, leaving other logged errors alone for the machine check handler to find and process. [ bp: Massage a bit and flip the "== 0" check to the usual !(..) test. ] Fixes: b79109c3bbcf ("x86, mce: separate correct machine check poller and fatal exception handler") Fixes: ed7290d0ee8f ("x86, mce: implement new status bits") Reported-by: Ashok Raj Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov Cc: Ashok Raj Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-edac Cc: Thomas Gleixner Cc: x86-ml Cc: Yazen Ghannam Link: https://lkml.kernel.org/r/20190312170938.GA23035@agluck-desk --- arch/x86/kernel/cpu/mce/core.c | 44 +++++++++++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index b7fb541a4873..e558ca77cfe8 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -712,19 +712,49 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b) barrier(); m.status = mce_rdmsrl(msr_ops.status(i)); + + /* If this entry is not valid, ignore it */ if (!(m.status & MCI_STATUS_VAL)) continue; /* - * Uncorrected or signalled events are handled by the exception - * handler when it is enabled, so don't process those here. - * - * TBD do the same check for MCI_STATUS_EN here? + * If we are logging everything (at CPU online) or this + * is a corrected error, then we must log it. */ - if (!(flags & MCP_UC) && - (m.status & (mca_cfg.ser ? MCI_STATUS_S : MCI_STATUS_UC))) - continue; + if ((flags & MCP_UC) || !(m.status & MCI_STATUS_UC)) + goto log_it; + + /* + * Newer Intel systems that support software error + * recovery need to make additional checks. Other + * CPUs should skip over uncorrected errors, but log + * everything else. + */ + if (!mca_cfg.ser) { + if (m.status & MCI_STATUS_UC) + continue; + goto log_it; + } + + /* Log "not enabled" (speculative) errors */ + if (!(m.status & MCI_STATUS_EN)) + goto log_it; + + /* + * Log UCNA (SDM: 15.6.3 "UCR Error Classification") + * UC == 1 && PCC == 0 && S == 0 + */ + if (!(m.status & MCI_STATUS_PCC) && !(m.status & MCI_STATUS_S)) + goto log_it; + + /* + * Skip anything else. Presumption is that our read of this + * bank is racing with a machine check. Leave the log alone + * for do_machine_check() to deal with it. + */ + continue; +log_it: error_seen = true; mce_read_aux(&m, i);