From: James Morse <james.morse@xxxxxxx> 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@xxxxxxx> Tested-by: Miguel Luis <miguel.luis@xxxxxxxxxx> Tested-by: Vishnu Pajjuri <vishnu@xxxxxxxxxxxxxxxxxxxxxx> Tested-by: Jianyong Wu <jianyong.wu@xxxxxxx> --- Changes since RFC v3: * Move IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU) into separate patch. Outstanding comments: https://lore.kernel.org/r/20230914153110.00003e38@xxxxxxxxxx https://lore.kernel.org/r/518859b1-64a9-d723-963c-56c7f6fc2da1@xxxxxxxxxx This contains a repeat of the IS_ENABLED() issue which we don't think is a problem - but there is another issue mentioned in that comment. --- drivers/acpi/acpi_processor.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index 01c460881662..19fceb3ec4e2 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -458,16 +458,13 @@ static int acpi_processor_add(struct acpi_device *device, } /* 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 (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) return; - if (!device || !acpi_driver_data(device)) - return; - pr = acpi_driver_data(device); if (pr->id >= nr_cpu_ids) goto out; @@ -504,6 +501,29 @@ static void acpi_processor_post_eject(struct acpi_device *device) kfree(pr); } +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_ARCH_MIGHT_HAVE_ACPI_PDC bool __init processor_physically_present(acpi_handle handle) { -- 2.30.2
