diff options
| author | James Morse <james.morse@arm.com> | 2021-07-02 16:48:41 +0100 |
|---|---|---|
| committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2023-08-29 15:30:08 +0100 |
| commit | 8a34ac66449388a2e3cd1825bd9ea59c5e72b17a (patch) | |
| tree | b870fe1499b28df0d3501873cfc2ce67b685e737 | |
| parent | 13bd3033d6e6f502da61bedd480891988f43813d (diff) | |
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@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
| -rw-r--r-- | drivers/acpi/acpi_processor.c | 31 | ||||
| -rw-r--r-- | 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 a02ee80db50e..a8f5d25b2015 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -446,13 +446,12 @@ 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); @@ -490,7 +489,29 @@ 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; @@ -559,9 +580,7 @@ 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 7efa3adc65a2..cb09e7ca1d95 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -80,6 +80,7 @@ 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); |