Commit d127db1a authored by James Morse's avatar James Morse Committed by Greg Kroah-Hartman
Browse files

arm64: setup: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu() 



To allow ACPI's _STA value to hide CPUs that are present, but not
available to online right now due to VMM or firmware policy, the
register_cpu() call needs to be made by the ACPI machinery when ACPI
is in use. This allows it to hide CPUs that are unavailable from sysfs.

Switching to GENERIC_CPU_DEVICES is an intermediate step to allow all
five ACPI architectures to be modified at once.

Switch over to GENERIC_CPU_DEVICES, and provide an arch_register_cpu()
that populates the hotpluggable flag. arch_register_cpu() is also the
interface the ACPI machinery expects.

The struct cpu in struct cpuinfo_arm64 is never used directly, remove
it to use the one GENERIC_CPU_DEVICES provides.

This changes the CPUs visible in sysfs from possible to present, but
on arm64 smp_prepare_cpus() ensures these are the same.

This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Reviewed-by: default avatar"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: default avatarShaoqin Huang <shahuang@redhat.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Signed-off-by: default avatar"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R3b-00Csza-Ku@rmk-PC.armlinux.org.uk


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ca00f7d9

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -132,6 +132,7 @@ config ARM64 
	select GENERIC_ARCH_TOPOLOGY

	select GENERIC_CLOCKEVENTS_BROADCAST

	select GENERIC_CPU_AUTOPROBE

	select GENERIC_CPU_DEVICES

	select GENERIC_CPU_VULNERABILITIES

	select GENERIC_EARLY_IOREMAP

	select GENERIC_IDLE_POLL_SETUP

arch/arm64/include/asm/cpu.h

+0 −1
Original line number Diff line number Diff line
@@ -38,7 +38,6 @@ struct cpuinfo_32bit { 
};



struct cpuinfo_arm64 {

	struct cpu	cpu;

	struct kobject	kobj;

	u64		reg_ctr;

	u64		reg_cntfrq;

arch/arm64/kernel/setup.c

+4 −9
Original line number Diff line number Diff line
@@ -402,19 +402,14 @@ static inline bool cpu_can_disable(unsigned int cpu) 
	return false;

}



static int __init topology_init(void)

int arch_register_cpu(int num)

{

	int i;

	struct cpu *cpu = &per_cpu(cpu_devices, num);



	for_each_possible_cpu(i) {

		struct cpu *cpu = &per_cpu(cpu_data.cpu, i);

		cpu->hotpluggable = cpu_can_disable(i);

		register_cpu(cpu, i);

	}

	cpu->hotpluggable = cpu_can_disable(num);



	return 0;

	return register_cpu(cpu, num);

}

subsys_initcall(topology_init);



static void dump_kernel_offset(void)

{