From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 E02ECF50E for ; Mon, 23 Oct 2023 08:45:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="YBhUuWgp" 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 A245CAF; Mon, 23 Oct 2023 01:45:01 -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=Apd3KeJ8uuP3OQFLQ5TzxVCBAuh86rEsBBY3n1LtHcM=; b=YBhUuWgpNULl2044fpGJ/4RiyU W2ygtuqlY99XtPXYBTEzLjRfuXprkm+9j4t032PBXwks89r8Z2UW0gWBXD81t1AKXGEa23oSnZ2Ac fy44mvrrt1gfHfc8UFjdtlb9+ta7o1rlQhgpBZVvUPoOSNxT+NFC3RVWyzyv7RLOEghIH25YZQe1W ZNdTbpo5oGx/qPAhtLcliiECxKCJOFs9jPB6FQBDw4kMfy3eoHHpTjQphSdbcucZfc6ejZ+hPA3LL 2CCikNXWTwCOrL4Sya5hdrgRD431/EbkJNy4a0c3U2bWPdaEaPH/7yQ+Jo+qll7sVFEAFfRwiYYq+ lQ0ZeaKg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:37836) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1quqYO-0002gI-2k; Mon, 23 Oct 2023 09:44:52 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1quqYN-0004g0-0h; Mon, 23 Oct 2023 09:44:51 +0100 Date: Mon, 23 Oct 2023 09:44:50 +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 24/35] drivers: base: Implement weak arch_unregister_cpu() Message-ID: References: <20230913163823.7880-1-james.morse@arm.com> <20230913163823.7880-25-james.morse@arm.com> <8be3a9dc-8f59-9ef9-3662-95814e177125@redhat.com> Precedence: bulk X-Mailing-List: linux-acpi@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: <8be3a9dc-8f59-9ef9-3662-95814e177125@redhat.com> Sender: Russell King (Oracle) On Tue, Sep 19, 2023 at 10:59:23AM +1000, Gavin Shan wrote: > On 9/14/23 02:38, James Morse wrote: > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > > index 677f963e02ce..c709747c4a18 100644 > > --- a/drivers/base/cpu.c > > +++ b/drivers/base/cpu.c > > @@ -531,7 +531,14 @@ int __weak arch_register_cpu(int cpu) > > { > > return register_cpu(&per_cpu(cpu_devices, cpu), cpu); > > } > > -#endif > > + > > +#ifdef CONFIG_HOTPLUG_CPU > > +void __weak arch_unregister_cpu(int num) > > +{ > > + unregister_cpu(&per_cpu(cpu_devices, num)); > > +} > > +#endif /* CONFIG_HOTPLUG_CPU */ > > +#endif /* CONFIG_GENERIC_CPU_DEVICES */ > > It seems conflicting with its declaration in include/linux/cpu.h. How so? The declaration is: extern void arch_unregister_cpu(int cpu); So: void __weak arch_unregister_cpu(int num) is compatible. > Besides, the function is still needed by > drivers/acpi/acpi_processor.c::acpi_processor_make_not_present() > even both CONFIG_HOTPLUG_CPU and CONFIG_GENERIC_CPU_DEVICES are disabled? Yes, I agree - it needs to be present when ACPI is built, so I'm thinking the right solution is to move it out from under at least CONFIG_HOTPLUG_CPU. It can't be moved out from under CONFIG_GENERIC_CPU_DEVICES because then we end up referencing the per-cpu variable cpu_devices which only exists when CONFIG_GENERIC_CPU_DEVICES is enabled. Is that a problem though, because in the case of !CONFIG_GENERIC_CPU_DEVICES, aren't architectures required to provide both arch_.*register_cpu() functions? Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!