The four ACPI architectures only create sysfs entries using register_cpu() for present CPUs, whereas GENERIC_CPU_DEVICES does this for possible CPUs.
Only two of the eight architectures that use GENERIC_CPU_DEVICES have a distinction between present and possible CPUs.
To allow all four ACPI architectures to use GENERIC_CPU_DEVICES, change it to use for_each_present_cpu().
The following architectures use GENERIC_CPU_DEVICES but are not SMP, so possible == present: * m68k * microblaze * nios2
The following architectures use GENERIC_CPU_DEVICES and consider possible == present: * csky: setup_smp() * hexagon: compare smp_start_cpus() and smp_prepare_cpus() * parisc: smp_prepare_boot_cpu() marks the boot cpu as present, processor_probe() sets possible for all CPUs and present for all CPUs except the boot cpu.
um appears to be a subarchitecture of x86.
The remaining architecture using GENERIC_CPU_DEVICES is openrisc, where smp_init_cpus() makes all CPUs < NR_CPUS possible, whereas smp_prepare_cpus() only makes CPUs < setup_max_cpus present. After this change, openrisc systems that boot with max_cpus=1 would not see other CPUs present in sysfs. This should not be a problem as these CPUs can't be brought online as _cpu_up() checks cpu_present().
Signed-off-by: James Morse james.morse@arm.com --- drivers/base/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 4c98849577d4..cf6407c34ede 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -500,7 +500,7 @@ static void __init cpu_dev_register_generic(void) #ifdef CONFIG_GENERIC_CPU_DEVICES int i;
- for_each_possible_cpu(i) { + for_each_present_cpu(i) { if (register_cpu(&per_cpu(cpu_devices, i), i)) panic("Failed to register CPU device"); }