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>
---
 kernel/cpu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index c89e0e91379a..16323610cd20 100644
--- 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

-- 
2.45.2

The following commit has been merged into the smp/core branch of tip:

Commit-ID:     2dce993165088dbe728faa21547e3b74213b6732
Gitweb:        https://git.kernel.org/tip/2dce993165088dbe728faa21547e3b74213b6732
Author:        Jiaxun Yang <jiaxun.yang@flygoat.com>
AuthorDate:    Tue, 16 Jul 2024 22:14:59 +08:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 02 Aug 2024 16:13:46 +02:00

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
---
 kernel/cpu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index c89e0e9..1632361 100644
--- 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