From patchwork Mon Jan 11 21:44:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Luck X-Patchwork-Id: 12011683 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 3C7FAC433DB for ; Mon, 11 Jan 2021 21:46:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 012D122CB8 for ; Mon, 11 Jan 2021 21:46:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731682AbhAKVqU (ORCPT ); Mon, 11 Jan 2021 16:46:20 -0500 Received: from mga14.intel.com ([192.55.52.115]:20892 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731244AbhAKVqU (ORCPT ); Mon, 11 Jan 2021 16:46:20 -0500 IronPort-SDR: SX9KRNCcOaCwHv2YBWGvMQP2KuzFy6EBTk+2zKJdemiIurw0jmzmRz6dnpZYe3BBTE4beRiTcU W4s9/9iwIm9A== X-IronPort-AV: E=McAfee;i="6000,8403,9861"; a="177166210" X-IronPort-AV: E=Sophos;i="5.79,339,1602572400"; d="scan'208";a="177166210" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jan 2021 13:45:08 -0800 IronPort-SDR: X4mXz3V4ZwtebLI/yZy2KXfk+qBWTED9qqdPXsjYD5tqRiH2UoJ4SxqZD1LZhzSpKaqg9IWTRL 4b6bbRJwj8pw== X-IronPort-AV: E=Sophos;i="5.79,339,1602572400"; d="scan'208";a="352760868" Received: from agluck-desk2.sc.intel.com ([10.3.52.68]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jan 2021 13:45:08 -0800 From: Tony Luck To: Borislav Petkov Cc: Tony Luck , x86@kernel.org, Andrew Morton , Peter Zijlstra , Darren Hart , Andy Lutomirski , linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2 2/3] x86/mce: Add new return value to get_user() for machine check Date: Mon, 11 Jan 2021 13:44:51 -0800 Message-Id: <20210111214452.1826-3-tony.luck@intel.com> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20210111214452.1826-1-tony.luck@intel.com> References: <20210108222251.14391-1-tony.luck@intel.com> <20210111214452.1826-1-tony.luck@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org When an exception occurs during any of the get_user() functions fixup_exception() passes the trap number of the exception in regs->ax to the fixup code. Check for X86_TRAP_MC and return -ENXIO ("No such device or address") so that callers can take action to avoid repeating an access to an address that has an uncorrectable error. Signed-off-by: Tony Luck --- arch/x86/lib/getuser.S | 8 +++++++- arch/x86/mm/extable.c | 1 + 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index fa1bc2104b32..c49a449fced6 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -17,7 +17,7 @@ * * Inputs: %[r|e]ax contains the address. * - * Outputs: %[r|e]ax is error code (0 or -EFAULT) + * Outputs: %[r|e]ax is error code (0 or -EFAULT or -ENXIO) * %[r|e]dx contains zero-extended value * %ecx contains the high half for 32-bit __get_user_8 * @@ -34,6 +34,7 @@ #include #include #include +#include #define ASM_BARRIER_NOSPEC ALTERNATIVE "", "lfence", X86_FEATURE_LFENCE_RDTSC @@ -168,8 +169,13 @@ SYM_CODE_START_LOCAL(.Lbad_get_user_clac) ASM_CLAC bad_get_user: xor %edx,%edx + cmpl $X86_TRAP_MC,%eax + je mce_get_user mov $(-EFAULT),%_ASM_AX ret +mce_get_user: + mov $(-ENXIO),%_ASM_AX + ret SYM_CODE_END(.Lbad_get_user_clac) #ifdef CONFIG_X86_32 diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index b93d6cd08a7f..ac4fcb820c40 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -77,6 +77,7 @@ __visible bool ex_handler_uaccess(const struct exception_table_entry *fixup, { WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?"); regs->ip = ex_fixup_addr(fixup); + regs->ax = trapnr; return true; } EXPORT_SYMBOL(ex_handler_uaccess);