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

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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: James Morse <james.morse@arm.com>
Reviewed-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R3b-00Csza-Ku@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
James Morse 2023-11-21 13:44:51 +00:00 committed by Greg Kroah-Hartman
parent ca00f7d999
commit d127db1a23
3 changed files with 5 additions and 10 deletions
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1
arch/arm64/Kconfig
View file

@ -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

1
arch/arm64/include/asm/cpu.h
View file

@ -38,7 +38,6 @@ struct cpuinfo_32bit {
};
struct cpuinfo_arm64 {
struct cpu cpu;
struct kobject kobj;
u64 reg_ctr;
u64 reg_cntfrq;

13
arch/arm64/kernel/setup.c
View file

@ -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)
{