cpu/hotplug: Provide weak fallback for arch_cpuhp_init_parallel_bringup()

CONFIG_HOTPLUG_PARALLEL expects the architecture to implement
arch_cpuhp_init_parallel_bringup() to decide whether paralllel hotplug is
possible and to do the necessary architecture specific initialization.

There are architectures which can enable it unconditionally and do not
require architecture specific initialization.

Provide a weak fallback for arch_cpuhp_init_parallel_bringup() so that
such architectures are not forced to implement empty stub functions.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240716-loongarch-hotplug-v3-2-af59b3bb35c8@flygoat.com

diff --git a/kernel/cpu.c b/kernel/cpu.c
index c89e0e91379a9fc157b4a64e7af6c421730cc27d..16323610cd20d78bf9282a0734f3e3bb2d36b59f 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1829,6 +1829,11 @@ static inline const struct cpumask *cpuhp_get_primary_thread_mask(void)
 }
 #endif
 
+bool __weak arch_cpuhp_init_parallel_bringup(void)
+{
+       return true;
+}
+
 /*
  * On architectures which have enabled parallel bringup this invokes all BP
  * prepare states for each of the to be onlined APs first. The last state