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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74C45EB64D7 for ; Tue, 20 Jun 2023 13:02:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232793AbjFTNCG (ORCPT ); Tue, 20 Jun 2023 09:02:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232790AbjFTNBb (ORCPT ); Tue, 20 Jun 2023 09:01:31 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 784B31BD5; Tue, 20 Jun 2023 06:01:16 -0700 (PDT) Date: Tue, 20 Jun 2023 13:00:52 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1687266053; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+dAf0GEt2bqtXlVtGRtDFvrC3WajYNjMM7B5erNke8E=; b=jVCRRZVh+lA0lLZlUw3HnBDGOL36IvOHtINUzSR5E26Z7TDDlMKtbgZcGibcp52BYaEflt 3rrq6UeYD9MDcdSQnV2Ip6sfPBIIB5W7fCPRwjGu0gnSlRQXUQSbqoPoy57nDIZTdRtUOa KLcv6csS3xTAzTuUpdOStDAxhlQX2lSYxy9AtniSN0yyXk+1NzRCyW4Vxr3KflQNjJxMGC K5zCZGS6zh7GtDtZEHuzJckDOGmrQ4g9PlreMgH0e1L1lh2cWH5iXSVCcH5/LGKo4wvdJN XiRkj6v9q/C8fYLZn1nq2Evj2uste8SQv8WLI0kJ6PELuo1/0sClozVrS3m3rQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1687266053; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+dAf0GEt2bqtXlVtGRtDFvrC3WajYNjMM7B5erNke8E=; b=ED35lgG54RyXwtKhzVfj8yzvysx/HWnIGHW0RCJ3ToamY0nkwLl3GodGOoiplMu9N5nijh hugQAq0m4XNoN/Cw== From: "tip-bot2 for Tony Battersby" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/core] x86/smp: Dont access non-existing CPUID leaf Cc: Tony Battersby , Thomas Gleixner , Mario Limonciello , "Borislav Petkov (AMD)" , stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <3817d810-e0f1-8ef8-0bbd-663b919ca49b@cybernetics.com> References: <3817d810-e0f1-8ef8-0bbd-663b919ca49b@cybernetics.com> MIME-Version: 1.0 Message-ID: <168726605213.404.14930030700633140033.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/core branch of tip: Commit-ID: 9b040453d4440659f33dc6f0aa26af418ebfe70b Gitweb: https://git.kernel.org/tip/9b040453d4440659f33dc6f0aa26af418ebfe70b Author: Tony Battersby AuthorDate: Thu, 15 Jun 2023 22:33:52 +02:00 Committer: Thomas Gleixner CommitterDate: Tue, 20 Jun 2023 14:51:46 +02:00 x86/smp: Dont access non-existing CPUID leaf stop_this_cpu() tests CPUID leaf 0x8000001f::EAX unconditionally. Intel CPUs return the content of the highest supported leaf when a non-existing leaf is read, while AMD CPUs return all zeros for unsupported leafs. So the result of the test on Intel CPUs is lottery. While harmless it's incorrect and causes the conditional wbinvd() to be issued where not required. Check whether the leaf is supported before reading it. [ tglx: Adjusted changelog ] Fixes: 08f253ec3767 ("x86/cpu: Clear SME feature flag when not in use") Signed-off-by: Tony Battersby Signed-off-by: Thomas Gleixner Reviewed-by: Mario Limonciello Reviewed-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/3817d810-e0f1-8ef8-0bbd-663b919ca49b@cybernetics.com Link: https://lore.kernel.org/r/20230615193330.322186388@linutronix.de --- arch/x86/kernel/process.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 05924bc..ff9b80a 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -763,6 +763,7 @@ struct cpumask cpus_stop_mask; void __noreturn stop_this_cpu(void *dummy) { + struct cpuinfo_x86 *c = this_cpu_ptr(&cpu_info); unsigned int cpu = smp_processor_id(); local_irq_disable(); @@ -777,7 +778,7 @@ void __noreturn stop_this_cpu(void *dummy) */ set_cpu_online(cpu, false); disable_local_APIC(); - mcheck_cpu_clear(this_cpu_ptr(&cpu_info)); + mcheck_cpu_clear(c); /* * Use wbinvd on processors that support SME. This provides support @@ -791,7 +792,7 @@ void __noreturn stop_this_cpu(void *dummy) * Test the CPUID bit directly because the machine might've cleared * X86_FEATURE_SME due to cmdline options. */ - if (cpuid_eax(0x8000001f) & BIT(0)) + if (c->extended_cpuid_level >= 0x8000001f && (cpuid_eax(0x8000001f) & BIT(0))) native_wbinvd(); /*