From: James Morse <james.morse@xxxxxxx> Architectures often have extra per-cpu work that needs doing before a CPU is registered, often to determine if a CPU is hotpluggable. To allow the ACPI architectures to use GENERIC_CPU_DEVICES, move the cpu_register() call into arch_register_cpu(), which is made __weak so architectures with extra work can override it. This aligns with the way x86, ia64 and loongarch register hotplug CPUs when they become present. Signed-off-by: James Morse <james.morse@xxxxxxx> Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx> --- Changes since RFC: * Dropped __init from x86/ia64 arch_register_cpu() Changes since RFC v2: * Dropped unnecessary Loongarch asm/cpu.h changes --- drivers/base/cpu.c | 14 ++++++++++---- include/linux/cpu.h | 4 ++++ 2 files changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 34b48f660b6b..579064fda97b 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -525,19 +525,25 @@ bool cpu_is_hotpluggable(unsigned int cpu) EXPORT_SYMBOL_GPL(cpu_is_hotpluggable); #ifdef CONFIG_GENERIC_CPU_DEVICES -static DEFINE_PER_CPU(struct cpu, cpu_devices); +DEFINE_PER_CPU(struct cpu, cpu_devices); + +int __weak arch_register_cpu(int cpu) +{ + return register_cpu(&per_cpu(cpu_devices, cpu), cpu); +} #endif static void __init cpu_dev_register_generic(void) { -#ifdef CONFIG_GENERIC_CPU_DEVICES int i; + if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES)) + return; + for_each_present_cpu(i) { - if (register_cpu(&per_cpu(cpu_devices, i), i)) + if (arch_register_cpu(i)) panic("Failed to register CPU device"); } -#endif } #ifdef CONFIG_GENERIC_CPU_VULNERABILITIES diff --git a/include/linux/cpu.h b/include/linux/cpu.h index fc8094419084..1e982d63eae8 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -88,6 +88,10 @@ extern ssize_t arch_cpu_probe(const char *, size_t); extern ssize_t arch_cpu_release(const char *, size_t); #endif +#ifdef CONFIG_GENERIC_CPU_DEVICES +DECLARE_PER_CPU(struct cpu, cpu_devices); +#endif + /* * These states are not related to the core CPU hotplug mechanism. They are * used by various (sub)architectures to track internal state -- 2.30.2