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: 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>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7b071a00425d2b833bc79dd0413bafaaeb94c19a..84bce830e365c2c8a2ed8f48d6499eea8c1b33f3 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -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

diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
index f3034099fd952b204f45a683c84dd4e42dad0314..b1e43f56ee461eb8f36222412057e90c42d6f6bf 100644 (file)
--- a/arch/arm64/include/asm/cpu.h
+++ b/arch/arm64/include/asm/cpu.h
@@ -38,7 +38,6 @@ struct cpuinfo_32bit {
 };
 
 struct cpuinfo_arm64 {
-       struct cpu      cpu;
        struct kobject  kobj;
        u64             reg_ctr;
        u64             reg_cntfrq;

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 417a8a86b2db595b5741b77a6c362502bb2f3617..165bd2c0dd5a7f9b469a9c765224a611a962a22f 100644 (file)
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -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)
 {