From mboxrd@z Thu Jan 1 00:00:00 1970 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D5A88C05027 for ; Tue, 14 Feb 2023 18:29:30 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4PGV9P1pKcz3c9L for ; Wed, 15 Feb 2023 05:29:29 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=bHhn4MxW; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=jpoimboe@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=bHhn4MxW; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4PGV8P4v2xz3c34 for ; Wed, 15 Feb 2023 05:28:37 +1100 (AEDT) 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 9971F61839; Tue, 14 Feb 2023 18:28:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5279BC433D2; Tue, 14 Feb 2023 18:28:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1676399315; bh=FbF6sDzVu8IYeXRzBwpTRcd2V9cyuwcFeFjq0Ymm7Do=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bHhn4MxW4jaWFJ2rWLLTx3PrN1UgQYhr8rIIi09a5nKp9q1ESDXYN6B61WfPK+RCk kGOo0Ttnppg2I0ImN2NZWVnYn5Hj3XaN0LDcyDf/bwqXXcmVPP3k8vhBjHFmJR2Bwl 59QsKYYCyuVJKOZH8QhykBvzswD6lxU5Dm7UQEUn/f61z0n0wk0iCLguGpDT9BQtko BMamtHKjb0Kw6J2wXAyHy1UIJAIQSjMfecn63l73DrJUySuInHCUTNK20Fu4b0MRwy oFsYNMAp0xS4VwbLeGrloRppo8ZqhdA7joLLtCUVdDhIWqqYlEK1n6Wnc+Yaj98vfY KvhcfOKc0ivxg== Date: Tue, 14 Feb 2023 10:28:31 -0800 From: Josh Poimboeuf To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH v2 13/24] sh/cpu: Make sure play_dead() doesn't return Message-ID: <20230214182831.7l73rzoeqjowbyly@treble> References: <2575e5f7-b11a-020f-06ef-ba42301d7415@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2575e5f7-b11a-020f-06ef-ba42301d7415@linaro.org> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: 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, 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, dietmar.eggemann@arm.com, linux-arm-kernel@lists.infradead.org, jgross@suse.com, chris@zankel.net, tsbogend@alpha.franken.de, bristot@redhat.com, linux-kern el@vger.kernel.org, linux-alpha@vger.kernel.org, bp@alien8.de, linuxppc-dev@lists.ozlabs.org, davem@davemloft.net Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Feb 14, 2023 at 08:57:39AM +0100, Philippe Mathieu-Daudé wrote: > On 14/2/23 08:05, Josh Poimboeuf wrote: > > play_dead() doesn't return. Make that more explicit with a BUG(). > > > > BUG() is preferable to unreachable() because BUG() is a more explicit > > failure mode and avoids undefined behavior like falling off the edge of > > the function into whatever code happens to be next. > > > > Signed-off-by: Josh Poimboeuf > > --- > > arch/sh/include/asm/smp-ops.h | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/sh/include/asm/smp-ops.h b/arch/sh/include/asm/smp-ops.h > > index e27702130eb6..63866b1595a0 100644 > > --- a/arch/sh/include/asm/smp-ops.h > > +++ b/arch/sh/include/asm/smp-ops.h > > @@ -27,6 +27,7 @@ static inline void plat_smp_setup(void) > > static inline void play_dead(void) > > { > > mp_ops->play_dead(); > > + BUG(); > > } > > Shouldn't we decorate plat_smp_ops::play_dead() as noreturn first? I guess it really depends on how far we want to go down the __noreturn rabbit hole. To keep the patch set constrained yet still useful I stopped when I got to a function pointer, as I think it still needs a BUG() afterwards either way. That said, there would still be benefits of adding __noreturn to function pointers, I just wanted to keep the patch set down to a manageable size ;-) -- Josh