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Message-Id: <20230203135043.409192-19-james.morse@arm.com>
Date: Fri, 3 Feb 2023 13:50:29 +0000
From: James Morse <james.morse@....com>
To: linux-pm@...r.kernel.org, loongarch@...ts.linux.dev,
kvmarm@...ts.linux.dev, kvm@...r.kernel.org,
linux-acpi@...r.kernel.org, linux-arch@...r.kernel.org,
linux-ia64@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, x86@...nel.org
Cc: Marc Zyngier <maz@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Sudeep Holla <sudeep.holla@....com>,
Borislav Petkov <bp@...en8.de>, H Peter Anvin <hpa@...or.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Huacai Chen <chenhuacai@...nel.org>,
James Morse <james.morse@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Oliver Upton <oliver.upton@...ux.dev>,
Len Brown <lenb@...nel.org>,
Rafael Wysocki <rafael@...nel.org>,
WANG Xuerui <kernel@...0n.name>,
Salil Mehta <salil.mehta@...wei.com>,
Russell King <linux@...linux.org.uk>,
Jean-Philippe Brucker <jean-philippe@...aro.org>
Subject: [RFC PATCH 18/32] ACPI: Check _STA present bit before making CPUs not present
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 <james.morse@....com>
---
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
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