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 7C4144F5DEE for ; Mon, 19 Oct 2026 13:09:35 +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=1792415376; cv=none; b=J4zT/HqZ9hlpboSepGQeKh6ixhGNqeuwtwyJUTZAuwQhIxQX6WnUM+0JP66c49Z+ml34DzFo+J+El4snEE3C5pkR5tAz/LsjMqjhsLjRANC9jKAuYIY2q1QKmQDq45B19286Rp+3oxnqrrnF0MQxkB1HN8ITOnU8rWdaWUx2S1Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792415376; c=relaxed/simple; bh=k1CaHKbZTa18Bgyna4lmqvaBNjEqvnjmg3voQKlH2Bs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CV53mnsjAghk4rGx9xK2eiG6Ur4Qt4m7SS2MTI+nPKaeXliNJchxY8sW9AUhT3QlY5LVapB8wBXoMzHWJH8MemXkNz7HjZG00YOTcVUZRnCXlrywSY6SdoC+So3DOZdA7OlIFXLaW05hRtl3HunKThuDs9uIGxjsvRgJgzJmjk8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IqPnIbfM; 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="IqPnIbfM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9334C1F000C5; Mon, 19 Oct 2026 13:09:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792415375; bh=F+7OQ7D99zBUWcKXmR6nwAllZD785ROGHMpCqf6hFSI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IqPnIbfMaf3qn6e7ZvIzXImxeewXsjgrrAZT4suwmBgNEDObCHzzSmrfQzT/tN05S 2dV911lfugPPx8edesd5F9XePidBHABF7n913XODpLz9wrrwG35MmU8QinpT2HwLjY IE2NJOdLOm62ffQ/QJ4rHEAl0eWs0xJL4t37wnM6w7uibJNDjR+3a24R2gi2ApaT0o 9EB05dXByktSzDHeFbjRjy53d49c9tcW1Cqj47mcOPfL9DrxMCPA6JmjVcCMxmdapP cTEhk50FCB6S4MPk2bZxJv8sRbX5OCOK9q70mrhVjC3WavesRa8z892ADlzzeQ7Jaq MluhGCk5JypJg== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Marco Crivellari , Peter Zijlstra , Phil Auld , Radu Rendec , Thomas Gleixner , Waiman Long Subject: [RFC PATCH 11/49] irqchip/aslint-sswi: Move CPUHP_AP_IRQ_ACLINT_SSWI_STARTING post stop_machine() Date: Mon, 19 Oct 2026 15:08:18 +0200 Message-ID: <20261019130856.49711-12-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(). The callback here simply disables the IPI in the per-CPU region, which nobody should touch concurrently because all other CPUs see the current one as offline at this stage. It also disables the per-CPU IRQ, which is internally protected by the IRQ desc lock. Therefore it can safely run concurrently with other CPUs. 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 661648ada894..6acf07afbaf5 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_IRQ_SIFIVE_PLIC_STARTING); + enum cpuhp_state target = max((int)st->target, CPUHP_AP_IRQ_ACLINT_SSWI_STARTING); 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_IRQ_SIFIVE_PLIC_STARTING); + WARN_ON(st->state != CPUHP_AP_IRQ_ACLINT_SSWI_STARTING); /* * Invoke the former CPU_DYING callbacks. DYING must not fail! */ -- 2.53.0