[PATCH] cpu-hotplug: provide prototypes for arch CPU registration

Russell King (Oracle)
2023-09-25T16:28:53Z

Provide common prototypes for arch_register_cpu() and
arch_unregister_cpu(). These are called by acpi_processor.c, with
weak versions, so the prototype for this is already set. It is
generally not necessary for function prototypes to be conditional
on preprocessor macros.

Some architectures (e.g. Loongarch) are missing the prototype for this,
and rather than add it to Loongarch's asm/cpu.h, lets do the job once
for everyone.

Since this covers everyone, remove the now unnecessary prototypes in
asm/cpu.h, and we also need to remove the 'static' from one of ia64's
arch_register_cpu() definitions.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
- drop ia64 changes, as ia64 has already been removed.

arch/x86/include/asm/cpu.h | 2 --
arch/x86/kernel/topology.c | 2 +-
include/linux/cpu.h | 2 ++
3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 3a233ebff712..25050d953eee 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -28,8 +28,6 @@ struct x86_cpu {
};

#ifdef CONFIG_HOTPLUG_CPU
-extern int arch_register_cpu(int num);
-extern void arch_unregister_cpu(int);
extern void soft_restart_cpu(void);
#endif

diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c
index ca004e2e4469..0bab03130033 100644
--- a/arch/x86/kernel/topology.c
+++ b/arch/x86/kernel/topology.c
@@ -54,7 +54,7 @@ void arch_unregister_cpu(int num)
EXPORT_SYMBOL(arch_unregister_cpu);
#else /* CONFIG_HOTPLUG_CPU */

-static int __init arch_register_cpu(int num)
+int __init arch_register_cpu(int num)
{
return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
}
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 0abd60a7987b..eb768a866fe3 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -80,6 +80,8 @@ extern __printf(4, 5)
struct device *cpu_device_create(struct device *parent, void *drvdata,
const struct attribute_group **groups,
const char *fmt, ...);
+extern int arch_register_cpu(int cpu);
+extern void arch_unregister_cpu(int cpu);
#ifdef CONFIG_HOTPLUG_CPU
extern void unregister_cpu(struct cpu *cpu);
extern ssize_t arch_cpu_probe(const char *, size_t);
--
2.30.2