From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E308B4C60; Fri, 3 Feb 2023 13:53:09 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B5CC61655; Fri, 3 Feb 2023 05:53:51 -0800 (PST) Received: from eglon.cambridge.arm.com (eglon.cambridge.arm.com [10.1.196.177]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E86E53F71E; Fri, 3 Feb 2023 05:53:05 -0800 (PST) From: James Morse To: linux-pm@vger.kernel.org, loongarch@lists.linux.dev, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org Cc: Marc Zyngier , Thomas Gleixner , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Borislav Petkov , H Peter Anvin , Dave Hansen , Ingo Molnar , Will Deacon , Catalin Marinas , Huacai Chen , James Morse , Suzuki K Poulose , Oliver Upton , Len Brown , Rafael Wysocki , WANG Xuerui , Salil Mehta , Russell King , Jean-Philippe Brucker Subject: [RFC PATCH 18/32] ACPI: Check _STA present bit before making CPUs not present Date: Fri, 3 Feb 2023 13:50:29 +0000 Message-Id: <20230203135043.409192-19-james.morse@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230203135043.409192-1-james.morse@arm.com> References: <20230203135043.409192-1-james.morse@arm.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When called acpi_processor_post_eject() unconditionally make a CPU not-present and unregisters it. To add support for AML events where the CPU has become disabled, but remains present, the _STA method should be checked before calling acpi_processor_remove(). Rename acpi_processor_post_eject() acpi_processor_remove_possible(), and check the _STA before calling. Adding the function prototype for arch_unregister_cpu() allows the preprocessor guards to be removed. After this change CPUs will remain registered and visible to user-space as offline if buggy firmware triggers an eject-request, but doesn't clear the corresponding _STA bits after _EJ0 has been called. Signed-off-by: James Morse --- drivers/acpi/acpi_processor.c | 31 +++++++++++++++++++++++++------ include/linux/cpu.h | 1 + 2 files changed, 26 insertions(+), 6 deletions(-) diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index ab0f80b83773..e6419b06cb37 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -409,13 +409,12 @@ static int acpi_processor_add(struct acpi_device *device, return result; } -#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU /* Removal */ -static void acpi_processor_post_eject(struct acpi_device *device) +static void acpi_processor_make_not_present(struct acpi_device *device) { struct acpi_processor *pr; - if (!device || !acpi_driver_data(device)) + if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) return; pr = acpi_driver_data(device); @@ -453,7 +452,29 @@ static void acpi_processor_post_eject(struct acpi_device *device) free_cpumask_var(pr->throttling.shared_cpu_map); kfree(pr); } -#endif /* CONFIG_ACPI_HOTPLUG_PRESENT_CPU */ + +static void acpi_processor_post_eject(struct acpi_device *device) +{ + struct acpi_processor *pr; + unsigned long long sta; + acpi_status status; + + if (!device) + return; + + pr = acpi_driver_data(device); + if (!pr || pr->id >= nr_cpu_ids || invalid_phys_cpuid(pr->phys_id)) + return; + + status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta); + if (ACPI_FAILURE(status)) + return; + + if (cpu_present(pr->id) && !(sta & ACPI_STA_DEVICE_PRESENT)) { + acpi_processor_make_not_present(device); + return; + } +} #ifdef CONFIG_X86 static bool acpi_hwp_native_thermal_lvt_set; @@ -522,9 +543,7 @@ static const struct acpi_device_id processor_device_ids[] = { static struct acpi_scan_handler processor_handler = { .ids = processor_device_ids, .attach = acpi_processor_add, -#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU .post_eject = acpi_processor_post_eject, -#endif .hotplug = { .enabled = true, }, diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 86e79e702325..f6f198a3972b 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -76,6 +76,7 @@ struct device *cpu_device_create(struct device *parent, void *drvdata, const struct attribute_group **groups, const char *fmt, ...); extern int arch_register_cpu(int cpu); +extern void arch_unregister_cpu(int cpu); #ifdef CONFIG_HOTPLUG_CPU extern void unregister_cpu(struct cpu *cpu); extern ssize_t arch_cpu_probe(const char *, size_t); -- 2.30.2