From patchwork Sat Sep 23 09:42:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13396661 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 541E0CE7A8B for ; Sat, 23 Sep 2023 10:12:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231733AbjIWKMh (ORCPT ); Sat, 23 Sep 2023 06:12:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231555AbjIWKMD (ORCPT ); Sat, 23 Sep 2023 06:12:03 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 455E5CDF; Sat, 23 Sep 2023 03:11:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695463912; x=1726999912; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=bNtEfhEic2/4eI6U3F6LZD3GtdQN7TZ08d/4AOd+L9I=; b=LZ2QO50YfqdDo8MkxH7jn0cK9EzSuhuOH0Liq8Ra7laGgJV7BFrLvuWl 5ck1IsGyzIYRExmfyAhQ+Np1MkhaCqbwV5hCpRg/4RmtJcKhzewsFR+BQ HvsQMGqpdeutNBdeoLotc22LW+zOBTxNbIdzWRYKUK+sAthn8iil/M8wo oRa4ZMrcRqwnx1/3B5UqTIm73vkbGSDY/FkC7V2rfXftOAf4ukNvTZTDT L+aUA9o3YbVNQ8XlAS/HTEgWI9y1H+H/errtdLfVo5TYuAj1ncCgOxifO SfJ23tBhmkeVnFxQbrAqWqAaQfrtTGCTS7DfVmlIymV9JpAtEHLl3iZFI w==; X-IronPort-AV: E=McAfee;i="6600,9927,10841"; a="447492399" X-IronPort-AV: E=Sophos;i="6.03,171,1694761200"; d="scan'208";a="447492399" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2023 03:11:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10841"; a="813388196" X-IronPort-AV: E=Sophos;i="6.03,171,1694761200"; d="scan'208";a="813388196" Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga008.fm.intel.com with ESMTP; 23 Sep 2023 03:11:49 -0700 From: Xin Li To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, pbonzini@redhat.com, seanjc@google.com, peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com, mhiramat@kernel.org, andrew.cooper3@citrix.com, jiangshanlai@gmail.com, nik.borisov@suse.com Subject: [PATCH v11 27/37] x86/fred: Add a machine check entry stub for FRED Date: Sat, 23 Sep 2023 02:42:02 -0700 Message-Id: <20230923094212.26520-28-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230923094212.26520-1-xin3.li@intel.com> References: <20230923094212.26520-1-xin3.li@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org Like #DB, when occurred on different ring level, i.e., from user or kernel context, #MCE needs to be handled on different stack: User #MCE on current task stack, while kernel #MCE on a dedicated stack. This is exactly how FRED event delivery invokes an exception handler: ring 3 event on level 0 stack, i.e., current task stack; ring 0 event on the #MCE dedicated stack specified in the IA32_FRED_STKLVLS MSR. So unlike IDT, the FRED machine check entry stub doesn't do stack switch. Tested-by: Shan Kang Signed-off-by: Xin Li --- Changes since v5: * Disallow #DB inside #MCE for robustness sake (Peter Zijlstra). --- arch/x86/kernel/cpu/mce/core.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 6f35f724cc14..da0a4a102afe 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -52,6 +52,7 @@ #include #include #include +#include #include "internal.h" @@ -2144,6 +2145,31 @@ DEFINE_IDTENTRY_MCE_USER(exc_machine_check) exc_machine_check_user(regs); local_db_restore(dr7); } + +#ifdef CONFIG_X86_FRED +/* + * When occurred on different ring level, i.e., from user or kernel + * context, #MCE needs to be handled on different stack: User #MCE + * on current task stack, while kernel #MCE on a dedicated stack. + * + * This is exactly how FRED event delivery invokes an exception + * handler: ring 3 event on level 0 stack, i.e., current task stack; + * ring 0 event on the #MCE dedicated stack specified in the + * IA32_FRED_STKLVLS MSR. So unlike IDT, the FRED machine check entry + * stub doesn't do stack switch. + */ +DEFINE_FREDENTRY_MCE(exc_machine_check) +{ + unsigned long dr7; + + dr7 = local_db_save(); + if (user_mode(regs)) + exc_machine_check_user(regs); + else + exc_machine_check_kernel(regs); + local_db_restore(dr7); +} +#endif #else /* 32bit unified entry point */ DEFINE_IDTENTRY_RAW(exc_machine_check)