From nobody Tue Dec 16 16:41:24 2025 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 AB4A8C07CA9 for ; Thu, 30 Nov 2023 21:16:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376870AbjK3VQ3 (ORCPT ); Thu, 30 Nov 2023 16:16:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376818AbjK3VQ0 (ORCPT ); Thu, 30 Nov 2023 16:16:26 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DDD40133; Thu, 30 Nov 2023 13:16:31 -0800 (PST) Date: Thu, 30 Nov 2023 21:16:29 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1701378990; 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=yX3GH4Ig3zJLPcZmocLBTO3REi3Ffcp+2bdeAOPF/9I=; b=HPuNHV2rzBeMM2AcgCScPh910tiNvGRT5f3PFBwbQAgvF2hVzf0kdxz2cesg/HL9tCTpEZ BxmR1Emz1HDMMdPEtvXu2Ks5Vg4sY3Ux/ruCE5hWOQzHBVfrJxoPjyNYXokpDSJTXzPA7U Yq786qD+oZBnSefPrZF1OgYIq5dLq5fuy8NJ+oMnIs5ahJegm6TCurO/PylKS+tnHuKUh7 mQB6i+beiRUef5UyzWLPbF8UEyGv5lSrdh3YrfL4boJU463rxecW9EJJOkYvQaHDSx8hi4 YAJNHuuoWPIE3v6segHiVeaWp1Gwk9NWvxRdaxChLO0Y1BP53KdLNJztoslbdw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1701378990; 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=yX3GH4Ig3zJLPcZmocLBTO3REi3Ffcp+2bdeAOPF/9I=; b=5GlV8IXEaCV43hIm2akKSs0HaL1J1S5moCBt8TQCBqrzT9IkjOTamdp8JJfA/z4XDU2YAp 5bcHKGWdLhq6UUBw== From: "tip-bot2 for Uros Bizjak" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/percpu] x86/smp: Move the call to smp_processor_id() after the early exit in native_stop_other_cpus() Cc: Uros Bizjak , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20231123203605.3474745-1-ubizjak@gmail.com> References: <20231123203605.3474745-1-ubizjak@gmail.com> MIME-Version: 1.0 Message-ID: <170137898974.398.10685540680447334314.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: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/percpu branch of tip: Commit-ID: 9d1c8f21533729b6ead531b676fa7d327cf00819 Gitweb: https://git.kernel.org/tip/9d1c8f21533729b6ead531b676fa7d327= cf00819 Author: Uros Bizjak AuthorDate: Thu, 23 Nov 2023 21:34:22 +01:00 Committer: Ingo Molnar CommitterDate: Thu, 30 Nov 2023 20:25:09 +01:00 x86/smp: Move the call to smp_processor_id() after the early exit in native= _stop_other_cpus() Improve code generation in native_stop_other_cpus() a tiny bit: smp_processor_id() accesses a per-CPU variable, so the compiler is not able to move the call after the early exit on its own. Also rename the "cpu" variable to a more descriptive "this_cpu", and use 'cpu' as a separate iterator variable later in the function. No functional change intended. Signed-off-by: Uros Bizjak Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20231123203605.3474745-1-ubizjak@gmail.com --- arch/x86/kernel/smp.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index 6eb06d0..65dd44e 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -148,14 +148,15 @@ static int register_stop_handler(void) =20 static void native_stop_other_cpus(int wait) { - unsigned int cpu =3D smp_processor_id(); + unsigned int this_cpu; unsigned long flags, timeout; =20 if (reboot_force) return; =20 /* Only proceed if this is the first CPU to reach this code */ - if (atomic_cmpxchg(&stopping_cpu, -1, cpu) !=3D -1) + this_cpu =3D smp_processor_id(); + if (atomic_cmpxchg(&stopping_cpu, -1, this_cpu) !=3D -1) return; =20 /* For kexec, ensure that offline CPUs are out of MWAIT and in HLT */ @@ -190,7 +191,7 @@ static void native_stop_other_cpus(int wait) * NMIs. */ cpumask_copy(&cpus_stop_mask, cpu_online_mask); - cpumask_clear_cpu(cpu, &cpus_stop_mask); + cpumask_clear_cpu(this_cpu, &cpus_stop_mask); =20 if (!cpumask_empty(&cpus_stop_mask)) { apic_send_IPI_allbutself(REBOOT_VECTOR); @@ -234,6 +235,8 @@ static void native_stop_other_cpus(int wait) * CPUs to stop. */ if (!smp_no_nmi_ipi && !register_stop_handler()) { + unsigned int cpu; + pr_emerg("Shutting down cpus with NMI\n"); =20 for_each_cpu(cpu, &cpus_stop_mask)