From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1134F1B9; Tue, 28 Nov 2023 07:08:58 -0800 (PST) Received: from mail.maildlp.com (unknown [172.18.186.31]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Sfm2J09dQz6J6pH; Tue, 28 Nov 2023 23:04:24 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id 3FA6614025A; Tue, 28 Nov 2023 23:08:56 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Tue, 28 Nov 2023 15:08:55 +0000 Date: Tue, 28 Nov 2023 15:08:54 +0000 From: Jonathan Cameron To: Russell King CC: , , , , , , , , , , , , , Salil Mehta , Jean-Philippe Brucker , , , James Morse , Catalin Marinas , Will Deacon Subject: Re: [PATCH RFC 13/22] arm64: setup: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu() Message-ID: <20231128150854.00005370@Huawei.com> In-Reply-To: References: Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500005.china.huawei.com (7.191.163.240) To lhrpeml500005.china.huawei.com (7.191.163.240) On Tue, 07 Nov 2023 10:30:25 +0000 Russell King wrote: > From: James Morse > > To allow ACPI's _STA value to hide CPUs that are present, but not > available to online right now due to VMM or firmware policy, the > register_cpu() call needs to be made by the ACPI machinery when ACPI > is in use. This allows it to hide CPUs that are unavailable from sysfs. > > Switching to GENERIC_CPU_DEVICES is an intermediate step to allow all > five ACPI architectures to be modified at once. > > Switch over to GENERIC_CPU_DEVICES, and provide an arch_register_cpu() > that populates the hotpluggable flag. arch_register_cpu() is also the > interface the ACPI machinery expects. > > The struct cpu in struct cpuinfo_arm64 is never used directly, remove > it to use the one GENERIC_CPU_DEVICES provides. > > This changes the CPUs visible in sysfs from possible to present, but > on arm64 smp_prepare_cpus() ensures these are the same. > > This patch also has the effect of moving the registration of CPUs from > subsys to driver core initialisation, prior to any initcalls running. > > Signed-off-by: James Morse > Reviewed-by: Russell King (Oracle) > Signed-off-by: Russell King (Oracle) Given this series adds an arch_cpu_is_hotpluggable() callback we probably want something in this patch description to say why this isn't using that, but instead overriding arch_register_cpu() Jonathan > --- > Changes since RFC v2: > * Add note about initialisation order change. > --- > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/cpu.h | 1 - > arch/arm64/kernel/setup.c | 13 ++++--------- > 3 files changed, 5 insertions(+), 10 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 7b071a00425d..84bce830e365 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -132,6 +132,7 @@ config ARM64 > select GENERIC_ARCH_TOPOLOGY > select GENERIC_CLOCKEVENTS_BROADCAST > select GENERIC_CPU_AUTOPROBE > + select GENERIC_CPU_DEVICES > select GENERIC_CPU_VULNERABILITIES > select GENERIC_EARLY_IOREMAP > select GENERIC_IDLE_POLL_SETUP > diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h > index f3034099fd95..b1e43f56ee46 100644 > --- a/arch/arm64/include/asm/cpu.h > +++ b/arch/arm64/include/asm/cpu.h > @@ -38,7 +38,6 @@ struct cpuinfo_32bit { > }; > > struct cpuinfo_arm64 { > - struct cpu cpu; > struct kobject kobj; > u64 reg_ctr; > u64 reg_cntfrq; > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > index 417a8a86b2db..165bd2c0dd5a 100644 > --- a/arch/arm64/kernel/setup.c > +++ b/arch/arm64/kernel/setup.c > @@ -402,19 +402,14 @@ static inline bool cpu_can_disable(unsigned int cpu) > return false; > } > > -static int __init topology_init(void) > +int arch_register_cpu(int num) > { > - int i; > + struct cpu *cpu = &per_cpu(cpu_devices, num); > > - for_each_possible_cpu(i) { > - struct cpu *cpu = &per_cpu(cpu_data.cpu, i); > - cpu->hotpluggable = cpu_can_disable(i); > - register_cpu(cpu, i); > - } > + cpu->hotpluggable = cpu_can_disable(num); > > - return 0; > + return register_cpu(cpu, num); > } > -subsys_initcall(topology_init); > > static void dump_kernel_offset(void) > {