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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5ACE6C433F5 for ; Thu, 4 Nov 2021 14:41:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44DAA611C1 for ; Thu, 4 Nov 2021 14:41:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231703AbhKDOns (ORCPT ); Thu, 4 Nov 2021 10:43:48 -0400 Received: from mail.skyhub.de ([5.9.137.197]:49286 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231402AbhKDOnb (ORCPT ); Thu, 4 Nov 2021 10:43:31 -0400 Received: from zn.tnic (p200300ec2f0f2b00bdd517953c60a78f.dip0.t-ipconnect.de [IPv6:2003:ec:2f0f:2b00:bdd5:1795:3c60:a78f]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 1E38F1EC0587; Thu, 4 Nov 2021 15:40:53 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1636036853; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+VcBvBeMaXnwlIMk+3o/pwLv3UEWJJA53DeSvk4bEPw=; b=G4SozZNqnGhw2nV7YHQ8KTccfzWcBgUxpHJvV9SwP8l1ODYcpMLSxL9K4U3NNJQva8Cnss LCGffMGteD/E7G3lTFiQNk7AflMWwkWiP/sFtj71EAp2TfR9zN68EooJ3LPPAA0BekHqm7 tCoHh2yaf+2UXKnyg0SWIUDw0uju+pY= From: Borislav Petkov To: Tony Luck Cc: X86 ML , LKML Subject: [PATCH v0 10/12] x86/mce: Move the tainting outside of the noinstr region Date: Thu, 4 Nov 2021 15:40:33 +0100 Message-Id: <20211104144035.20107-11-bp@alien8.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20211104144035.20107-1-bp@alien8.de> References: <20211104144035.20107-1-bp@alien8.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov add_taint() is yet another external facility which the #MC handler calls. Move that tainting call into the instrumentation-allowed part of the handler. Fixes vmlinux.o: warning: objtool: do_machine_check()+0x617: call to add_taint() leaves .noinstr.text section While at it, drop noinstr tracking around mce_log(). Fixes vmlinux.o: warning: objtool: do_machine_check()+0x690: call to mce_log() leaves .noinstr.text section Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/mce/core.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index e31df79f87c7..961f80a4bd6f 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -1175,13 +1175,14 @@ static noinstr bool mce_check_crashing_cpu(void) return false; } -static void __mc_scan_banks(struct mce *m, struct pt_regs *regs, struct mce *final, - unsigned long *toclear, unsigned long *valid_banks, - int no_way_out, int *worst) +static __always_inline int +__mc_scan_banks(struct mce *m, struct pt_regs *regs, struct mce *final, + unsigned long *toclear, unsigned long *valid_banks, int no_way_out, + int *worst) { struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); struct mca_config *cfg = &mca_cfg; - int severity, i; + int severity, i, taint = 0; for (i = 0; i < this_cpu_read(mce_num_banks); i++) { __clear_bit(i, toclear); @@ -1208,7 +1209,7 @@ static void __mc_scan_banks(struct mce *m, struct pt_regs *regs, struct mce *fin continue; /* Set taint even when machine check was not enabled. */ - add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE); + taint++; severity = mce_severity(m, regs, cfg->tolerant, NULL, true); @@ -1231,7 +1232,9 @@ static void __mc_scan_banks(struct mce *m, struct pt_regs *regs, struct mce *fin /* assuming valid severity level != 0 */ m->severity = severity; + instrumentation_begin(); mce_log(m); + instrumentation_end(); if (severity > *worst) { *final = *m; @@ -1241,6 +1244,8 @@ static void __mc_scan_banks(struct mce *m, struct pt_regs *regs, struct mce *fin /* mce_clear_state will clear *final, save locally for use later */ *m = *final; + + return taint; } static void kill_me_now(struct callback_head *ch) @@ -1349,7 +1354,7 @@ static noinstr void unexpected_machine_check(struct pt_regs *regs) */ noinstr void do_machine_check(struct pt_regs *regs) { - int worst = 0, order, no_way_out, kill_current_task, lmce; + int worst = 0, order, no_way_out, kill_current_task, lmce, taint = 0; DECLARE_BITMAP(valid_banks, MAX_NR_BANKS) = { 0 }; DECLARE_BITMAP(toclear, MAX_NR_BANKS) = { 0 }; struct mca_config *cfg = &mca_cfg; @@ -1428,7 +1433,7 @@ noinstr void do_machine_check(struct pt_regs *regs) order = mce_start(&no_way_out); } - __mc_scan_banks(&m, regs, final, toclear, valid_banks, no_way_out, &worst); + taint = __mc_scan_banks(&m, regs, final, toclear, valid_banks, no_way_out, &worst); if (!no_way_out) mce_clear_state(toclear); @@ -1460,11 +1465,14 @@ noinstr void do_machine_check(struct pt_regs *regs) } } + instrumentation_begin(); + + if (taint) + add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE); + if (worst != MCE_AR_SEVERITY && !kill_current_task) goto out; - instrumentation_begin(); - /* Fault was in user mode and we need to take some action */ if ((m.cs & 3) == 3) { /* If this triggers there is no way to recover. Die hard. */ @@ -1494,9 +1502,9 @@ noinstr void do_machine_check(struct pt_regs *regs) queue_task_work(&m, msg, kill_me_never); } +out: instrumentation_end(); -out: mce_wrmsrl(MSR_IA32_MCG_STATUS, 0); } EXPORT_SYMBOL_GPL(do_machine_check); -- 2.29.2