From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta1.migadu.com (out-183.mta1.migadu.com [95.215.58.183]) (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 450AA299928 for ; Tue, 11 Nov 2025 07:00:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762844416; cv=none; b=XTY5xLviwk6DOPuLSfmikI/oI1PCvv8yfEzEIMTgKpcRaSrbPnQZOWFRcKMA6inSeKXA8yzwO4z/sfWB7wFZxDKs5VBcw0oQxoi9Oi/s2xbDZczs1LtdbaIbCjyVKcYV/e/jME6eXqN3UKNnNinAYSDyH0G4ArU7Mn3ia/mu+T0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762844416; c=relaxed/simple; bh=lkoyytZzlJir/rENDnqrYHU7rJ/u7rlWl9dM0tePmqU=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=fb6gIPT8i7iZnvcDfBhid42VH8H4i194C4+7H/lKazkqGLVbBwtAj7eZbc81rRhGA2JyWEV21SXDqWezANTvONswb33amTiMQVGb5MU17nXidCH7+aS4T+ZERC5r5koAGWrWTopvbckqjRYcoQR1A8zOWG53HX1sG4cFSZ3FV1Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=bTGk8HB/; arc=none smtp.client-ip=95.215.58.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="bTGk8HB/" Content-Type: text/plain; charset=us-ascii DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1762844411; h=from:from: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=PKizkMmVoN2fp8ZV4SExztn9QwUvKPF0m1z1rnF/wtA=; b=bTGk8HB/wfytTP/uAxt75Q8GD5jT7jBfTt5KdC2xGpmqFyjstiPrFZRVKHDExo8qyxvZrN uJcPeTanJuXhKET6AwSKAXC+EOL1ohzcjGQrBzeiNQ3jMUSGcOVT7YCMi4KK8Bp4LerS5P uB74PhdUwRspPUv6jkL2hHN/CulQjsY= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3826.700.81\)) Subject: Re: [PATCH 1/5] s390/ipl: Mark store_status as __noreturn X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Thorsten Blum In-Reply-To: <20251110150635.15528B2f-hca@linux.ibm.com> Date: Tue, 11 Nov 2025 08:00:00 +0100 Cc: Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: 7bit Message-Id: <7AD8A2F3-96E1-4C72-8E06-55BA50C9CFF1@linux.dev> References: <20251110132803.1520-1-thorsten.blum@linux.dev> <20251110150635.15528B2f-hca@linux.ibm.com> To: Heiko Carstens X-Migadu-Flow: FLOW_OUT On 10. Nov 2025, at 16:06, Heiko Carstens wrote: > On Mon, Nov 10, 2025 at 02:27:51PM +0100, Thorsten Blum wrote: >> store_status() performs a tail call (BR_EX) to the function passed as >> the first parameter and does not return. Annotate the declaration with >> the __noreturn attribute to improve compiler optimizations. >> >> Signed-off-by: Thorsten Blum >> --- >> arch/s390/include/asm/ipl.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) > > This doesn't make any sense. If a function is called, which calls > another one with a tail call, then _of course_ it looks to the caller > like the function returned. Hm, I must have misunderstood this comment from arch/s390/kernel/machine_kexec.c: /* * ... * The call to store_status() will not return. */ store_status(__do_machine_kdump, image);