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 50502C64ED6 for ; Wed, 15 Feb 2023 19:45:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229477AbjBOTpr (ORCPT ); Wed, 15 Feb 2023 14:45:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229651AbjBOTpn (ORCPT ); Wed, 15 Feb 2023 14:45:43 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E04233BD8F; Wed, 15 Feb 2023 11:45:42 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7E36461D23; Wed, 15 Feb 2023 19:45:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43254C433EF; Wed, 15 Feb 2023 19:45:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1676490341; bh=jEHEKJREN3+faSwa9KQfDCZrIk1boGFeW1CEIEtwaE8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nR0NlH9Idu9r6K5BB6SiskW/nN4Duv8oUu4t8oAsMW/BA2jHnn50sUmTtFA09snEM MM4Q1KeVxIEK0CQ3heZ6KGEcJDJrmingPvv4ff3yLJnpeg2zJ4He1vCJjQd4s9mOGJ HhE0qrDT5xUO3xGvs5zweCTvugYIA2adLOusrfvLPAxv6b4Cny+j0eHRlRanyAeAV0 ysxu48fte0a0SA7XcnPw1U31MXQzSfjcPpTrp4Qgi04O07kA/LeXjWVthIX5CMIF30 JAfOEJGYLSGZoEytWeIGwTCLRlwIMdQ5V+BaoKw5Pr+bw7iEZ2yNGIfGT3LJDZnQTo qDwCO7AGpVLow== Date: Wed, 15 Feb 2023 11:45:38 -0800 From: Josh Poimboeuf To: Mark Rutland Cc: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , juri.lelli@redhat.com, dalias@libc.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, peterz@infradead.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, x86@kernel.org, jiaxun.yang@flygoat.com, linux-mips@vger.kernel.org, bsegall@google.com, jcmvbkbc@gmail.com, guoren@kernel.org, hpa@zytor.com, sparclinux@vger.kernel.org, kernel@xen0n.name, will@kernel.org, vschneid@redhat.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, ysato@users.sourceforge.jp, chenhuacai@kernel.org, linux@armlinux.org.uk, linux-csky@vger.kernel.org, dietmar.eggemann@arm.com, mingo@redhat.com, bcm-kernel-feedback-list@broadcom.com, mgorman@suse.de, mattst88@gmail.com, linux-xtensa@linux-xtensa.org, paulmck@kernel.org, richard.henderson@linaro.org, npiggin@gmail.com, ink@jurassic.park.msu.ru, rostedt@goodmis.org, loongarch@lists.linux.dev, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, jgross@suse.com, chris@zankel.net, tsbogend@alpha.franken.de, bristot@redhat.com, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, bp@alien8.de, linuxppc-dev@lists.ozlabs.org, davem@davemloft.net Subject: Re: [PATCH v2 04/24] arm64/cpu: Mark cpu_die() __noreturn Message-ID: <20230215194538.aiiris3uabnuvkkg@treble> References: <14274f04-2991-95bd-c29b-07e86e8755c1@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 15, 2023 at 01:09:21PM +0000, Mark Rutland wrote: > On Tue, Feb 14, 2023 at 09:13:08AM +0100, Philippe Mathieu-Daudé wrote: > > On 14/2/23 08:05, Josh Poimboeuf wrote: > > > cpu_die() doesn't return. Annotate it as such. By extension this also > > > makes arch_cpu_idle_dead() noreturn. > > > > > > Signed-off-by: Josh Poimboeuf > > > --- > > > arch/arm64/include/asm/smp.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h > > > index fc55f5a57a06..5733a31bab08 100644 > > > --- a/arch/arm64/include/asm/smp.h > > > +++ b/arch/arm64/include/asm/smp.h > > > @@ -100,7 +100,7 @@ static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask) > > > extern int __cpu_disable(void); > > > extern void __cpu_die(unsigned int cpu); > > > -extern void cpu_die(void); > > > +extern void __noreturn cpu_die(void); > > > extern void cpu_die_early(void); > > > > Shouldn't cpu_operations::cpu_die() be declared noreturn first? > > The cpu_die() function ends with a BUG(), and so does not return, even if a > cpu_operations::cpu_die() function that it calls erroneously returned. > > We *could* mark cpu_operations::cpu_die() as noreturn, but I'd prefer that we > did not so that the compiler doesn't optimize away the BUG() which is there to > catch such erroneous returns. > > That said, could we please add __noreturn to the implementation of cpu_die() in > arch/arm64/kernel/smp.c? i.e. the fixup below. Done. > With that fixup: > > Acked-by: Mark Rutland Thanks! -- Josh