diff options
| -rw-r--r-- | arch/arm64/kernel/smp.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index a755b9f902fa..1c84375f978e 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -511,6 +511,59 @@ static int __init smp_cpu_setup(int cpu) static bool bootcpu_valid __initdata; static unsigned int cpu_count = 1; +int arch_register_cpu(int cpu) +{ + acpi_handle acpi_handle = acpi_get_processor_handle(cpu); + struct cpu *c = &per_cpu(cpu_devices, cpu); + + if (!acpi_disabled && !acpi_handle && + IS_ENABLED(CONFIG_ACPI_HOTPLUG_CPU)) + return -EPROBE_DEFER; + +#ifdef CONFIG_ACPI_HOTPLUG_CPU + /* For now block anything that looks like physical CPU Hotplug */ + if (invalid_logical_cpuid(cpu) || !cpu_present(cpu)) { + pr_err_once("Changing CPU present bit is not supported\n"); + return -ENODEV; + } +#endif + + /* + * Availability of the acpi handle is sufficient to establish + * that _STA has aleady been checked. No need to recheck here. + */ + c->hotpluggable = arch_cpu_is_hotpluggable(cpu); + + return register_cpu(c, cpu); +} + +#ifdef CONFIG_ACPI_HOTPLUG_CPU +void arch_unregister_cpu(int cpu) +{ + acpi_handle acpi_handle = acpi_get_processor_handle(cpu); + struct cpu *c = &per_cpu(cpu_devices, cpu); + acpi_status status; + unsigned long long sta; + + if (!acpi_handle) { + pr_err_once("Removing a CPU without associated ACPI handle\n"); + return; + } + + status = acpi_evaluate_integer(acpi_handle, "_STA", NULL, &sta); + if (ACPI_FAILURE(status)) + return; + + /* For now do not allow anything that looks like physical CPU HP */ + if (cpu_present(cpu) && !(sta & ACPI_STA_DEVICE_PRESENT)) { + pr_err_once("Changing CPU present bit is not supported\n"); + return; + } + + unregister_cpu(c); +} +#endif /* CONFIG_ACPI_HOTPLUG_CPU */ + #ifdef CONFIG_ACPI static struct acpi_madt_generic_interrupt cpu_madt_gicc[NR_CPUS]; |