From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A2B851AFCE for ; Mon, 19 Oct 2026 13:11:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792415476; cv=none; b=fYCNu8LJdKFJZAYScRNy8c6f2L30a2SdVrVzVmPqmtQjJo19x+VuW23QWzoaCxBqWLnb/Mx/svkEjCa9O94P3X7iVYab8EgIe3U9ICd7FM+tuPUXPvguy/zwc7EwNxyCPvgyU3Ev1iR2WWeXHYac5fos2Krq7O8csPz4omGX6Uc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792415476; c=relaxed/simple; bh=H6/Q2TVBdBP57MtczPjj0vxQqab9RCuJ0Zuyi4Zb5rk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NSQQdLXKQv1K8fStkZ5ZlCTMz9JRa/Smme8P2xd0OKMladNw3IDgBj3Xp+WH0wv+BM7VF/oTT+Ly34uk7Rb6Z963VHLUHSocVDRltUalP3dH3f3AC5XCHyEM3r8H6LBtfk5r8nBFOF3Gsxy47hrgRPKQzDu+JjAA5XAAvmNQzp8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XmacM4HP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XmacM4HP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC68B1F000C6; Mon, 19 Oct 2026 13:11:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792415474; bh=xrvtHIQ66eMDyIWnguwKjohMEyUJ6ZEzNiuzwJ8D6sE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=XmacM4HP2351LhSNVP9HpBQ5p2NjBqeXQ1uCJ6oFN/kplUlm0Zx4mQcVXoHbOT3RL 4/OGB3P1rAWN0tV/XPWXih8Gl2xz2E+xUko3NFyK/X8kRA109n3gs/vuQJoq8MZp6Y WWm0dHbNVMKZzYHo9vpYJH8T/NiyPJQyNAvwRkjSoKmAlGRUdzyxXikgjt6MlBmSKb b7gae3bGB6o9SGRBqqAivQbjySBzqsGYOS+/VSyZaNRH6/IjlHnqaAlaxBsayDBzxl XQSyCVVsJmiutQR/S4KXp+uAfS1vQBx0I7/L9thatmOQZ+XjyO8gnEYwXRcrQnyO63 uYWCSDY9jv9lA== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , "H. Peter Anvin" , Borislav Petkov , Dave Hansen , Ingo Molnar , Marco Crivellari , Ning Sun , Peter Zijlstra , Phil Auld , Thomas Gleixner , Waiman Long , tboot-devel@lists.sourceforge.net, x86@kernel.org Subject: [RFC PATCH 48/49] x86/boot/tboot: Move CPUHP_AP_X86_TBOOT_DYING post stop_machine() Date: Mon, 19 Oct 2026 15:08:55 +0200 Message-ID: <20261019130856.49711-49-frederic@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261019130856.49711-1-frederic@kernel.org> References: <20261019130856.49711-1-frederic@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Between CPUHP_TEARDOWN_CPU and CPUHP_AP_OFFLINE, stop_machine executes all the teardown callbacks while stopping all CPUs in the system. This doesn't mix-up well with running RT or isolated tasks. In order to transition smoothly from global stop_machine to finer grained synchronization between teardown callbacks and the other CPUs, a new stop machine post function has been introduced to be executed after the main one with IRQs still disabled while other CPUs can exit stop_machine(). tboot waits for all previously outgoing CPUs to be in Wait-For-SIPI mode when the last secondary CPU goes down. Although the expectation looks strange because the number in ap_wfs_count should only match tboot->num_in_wfs + 1 at this hotplug stage, anyway the CPU can run this wait loop while the other online CPU is running concurrently. Move this teardown callback to post stop_machine() accordingly. Signed-off-by: Frederic Weisbecker --- kernel/cpu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index 59ffcd4534c8..87680f7c6493 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1275,7 +1275,7 @@ void clear_tasks_mm_cpumask(int cpu) static int take_cpu_down(void *_param) { struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); - enum cpuhp_state target = max((int)st->target, CPUHP_AP_TICK_DYING); + enum cpuhp_state target = max((int)st->target, CPUHP_AP_X86_TBOOT_DYING); int err, cpu = smp_processor_id(); /* Ensure this CPU doesn't handle any more interrupts. */ @@ -1303,7 +1303,7 @@ static int take_cpu_down_post(void *_param) enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); int cpu = smp_processor_id(); - WARN_ON(st->state != CPUHP_AP_TICK_DYING); + WARN_ON(st->state != CPUHP_AP_X86_TBOOT_DYING); /* * Invoke the former CPU_DYING callbacks. DYING must not fail! */ -- 2.53.0