From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 745704315F for ; Fri, 26 Jun 2026 17:07:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782493639; cv=none; b=k7b9rJrlP8X3MIZeIE7gjcHRxsq5KHFdAwGUh8N1bTJsX2H9O34CTnx6iIT1xnmedLGftdMWpDLcfIH4SzDXQYJnBeuk2IKgGMFH9l/e2gvbOk6KFVGDXL4EedXtG2vVdx1WIAtJ0CsM+BOz8Dq50Ydlj8RCLtJ+GNyY7H6vATg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782493639; c=relaxed/simple; bh=ylfDgokWIdBatf69Bqo3iSYQXfGqiAjcEuPHy5u2PLE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=B/iBdpb7sONTqI0oxXgrEg/YaCeXpsuVd6oFwoXRtb0Ph21ajPK0yRoZEyYF4nUErlChgzEy0dfcee93l607WhKHiyYa3wt380Yt1nUlOcsxeToCYXmfrklZijYT3YmQTf70tMwhfJXr2I6wwVEJnra7CQkPzXZQRd+Qgt8DgdM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=JP49E4PS; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="JP49E4PS" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 036DB1F60; Fri, 26 Jun 2026 10:07:12 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 793AD3F632; Fri, 26 Jun 2026 10:07:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782493636; bh=ylfDgokWIdBatf69Bqo3iSYQXfGqiAjcEuPHy5u2PLE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JP49E4PS3c5WyTeeBtQ7DS3TS1dFSwX05hGVEdAiV/ydyNWiIoWTMyKGrntMHB5dI s0qam6HkCI7dSTGsU7vZFmYIBYwP04z5RiCm9QrZa0B1OI1eSswlpKSdhpyCb5TxIZ T0hMZ+udy2aE80t9jhGwoDxt47L+MGlZ1QCEtw6w= Date: Fri, 26 Jun 2026 18:07:10 +0100 From: Catalin Marinas To: Kiryl Shutsemau Cc: Will Deacon , James Morse , Mark Rutland , Marc Zyngier , Doug Anderson , Petr Mladek , Thomas Gleixner , Andrew Morton , Baoquan He , Puranjay Mohan , Usama Arif , Breno Leitao , Julien Thierry , Lecopzer Chen , Sumit Garg , kernel-team@meta.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "Kiryl Shutsemau (Meta)" Subject: Re: [PATCH v4 0/4] arm64: cross-CPU NMI via SDEI Message-ID: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Jun 17, 2026 at 08:20:01PM +0100, Kiryl Shutsemau wrote: > - A CPU stopped by the SDEI rung is parked, not powered off via PSCI > CPU_OFF. Reaching and dumping the wedged CPU -- the point of the > series -- works, and it matches the shared stop path's own park > fallback when CPU_OFF is unavailable. The consequence is that an SMP > crash-capture kernel cannot re-online such a CPU (it stays "already > on"); the capture kernel boots and runs on the remaining CPUs. > Powering the stopped CPU off so a capture kernel can reclaim it > requires completing the SDEI event and then CPU_OFF, which hit a > firmware-specific issue still under investigation; it is left as a > follow-up and does not affect the dump's contents. Just to understand, your firmware cannot cope with a PSCI CPU_OFF from the SDEI handler? This is one of the required calls to be supported. -- Catalin