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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B54F6CDB47E for ; Fri, 20 Oct 2023 11:16:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377028AbjJTLQl (ORCPT ); Fri, 20 Oct 2023 07:16:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376927AbjJTLQk (ORCPT ); Fri, 20 Oct 2023 07:16:40 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 759A6CA; Fri, 20 Oct 2023 04:16:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=H2KpfR5v8S4cDdfvm+k1Bez67vNujA5KyI4fx/Kz1ps=; b=YgzekWfuW0ZViZvyoL/HkzAklX 5nNW5eMYQMXCcU1QdSAFp2AF9Q1KXT5sTeSAtHnZQ/m8i4B1L6Ep823thvglTw3UyUImbkgwmhyDu MWPWCuvm+LO5NStcvSOzrl1wG8pWuXD90e/dP8XNx6EIoA8ioI/CtepzCL35KbgwdacIxoz7mGI0F aAGqzFHJ+LL7bswWK1eApS9KxsLw/kGe4s0eICUD05jcwZeCgM6IuF5ubji454/lne12SDBrPNFFP ENRAcGT1B4VSpRgHHWxzJeLbxeXoi6OVeMDVOCfQ9ss1HnYNq3wNODcnMv5WKQEWbebV+eeFzrEiE Y3Xx91tQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:50880) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qtnUT-0000Id-1M; Fri, 20 Oct 2023 12:16:29 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1qtnUS-0001UG-19; Fri, 20 Oct 2023 12:16:28 +0100 Date: Fri, 20 Oct 2023 12:16:27 +0100 From: "Russell King (Oracle)" To: Gavin Shan Cc: James Morse , linux-pm@vger.kernel.org, loongarch@lists.linux.dev, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev, x86@kernel.org, Salil Mehta , Jean-Philippe Brucker , jianyong.wu@arm.com, justin.he@arm.com Subject: Re: [RFC PATCH v2 05/35] drivers: base: Print a warning instead of panic() when register_cpu() fails Message-ID: References: <20230913163823.7880-1-james.morse@arm.com> <20230913163823.7880-6-james.morse@arm.com> <2c23ab17-7516-e310-8b79-b8c5fc02984a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2c23ab17-7516-e310-8b79-b8c5fc02984a@redhat.com> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Mon, Sep 18, 2023 at 01:33:37PM +1000, Gavin Shan wrote: > > > On 9/14/23 02:37, James Morse wrote: > > loongarch, mips, parisc, riscv and sh all print a warning if > > register_cpu() returns an error. Architectures that use > > GENERIC_CPU_DEVICES call panic() instead. > > > > Errors in this path indicate something is wrong with the firmware > > description of the platform, but the kernel is able to keep running. > > > > Downgrade this to a warning to make it easier to debug this issue. > > > > This will allow architectures that switching over to GENERIC_CPU_DEVICES > > to drop their warning, but keep the existing behaviour. > > > > Signed-off-by: James Morse > > --- > > drivers/base/cpu.c | 7 ++++--- > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > > index 579064fda97b..d31c936f0955 100644 > > --- a/drivers/base/cpu.c > > +++ b/drivers/base/cpu.c > > @@ -535,14 +535,15 @@ int __weak arch_register_cpu(int cpu) > > static void __init cpu_dev_register_generic(void) > > { > > - int i; > > + int i, ret; > > if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES)) > > return; > > for_each_present_cpu(i) { > > - if (arch_register_cpu(i)) > > - panic("Failed to register CPU device"); > > + ret = arch_register_cpu(i); > > + if (ret) > > + pr_warn("register_cpu %d failed (%d)\n", i, ret); > > } > > } > > The same warning message has been printed by arch/loongarch/kernel/topology.c::arch_register_cpu(). > In order to avoid the duplication, I think the warning message in arch/loongarch needs to be dropped? No it doesn't, as far as Loongarch is concerned. Given where this change occurs in the series, it is correct as far as this is concerned. The reason is that this code path can only be reached when CONFIG_GENERIC_CPU_DEVICES is set, which is something the arch has to select. Loongarch doesn't select that until patch 9 in the series, "LoongArch: Switch over to GENERIC_CPU_DEVICES", and that patch is where the warning message in arch/loongarch is removed. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!