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* [RFC PATCH 37/49] clocksource/drivers/c-sky: Move CPUHP_AP_CSKY_TIMER_STARTING post stop_machine()
       [not found] <20261019130856.49711-1-frederic@kernel.org>
@ 2026-10-19 13:08 ` Frederic Weisbecker
  0 siblings, 0 replies; only message in thread
From: Frederic Weisbecker @ 2026-10-19 13:08 UTC (permalink / raw)
  To: LKML
  Cc: Frederic Weisbecker, Daniel Lezcano, Guo Ren, Marco Crivellari,
	Peter Zijlstra, Phil Auld, Thomas Gleixner, Waiman Long,
	linux-csky

Between CPUHP_TEARDOWN_CPU and CPUHP_AP_OFFLINE, stop_machine executes
all the teardown callbacks while stopping all CPUs in the system. This
doesn't mix-up well with running RT or isolated tasks.

In order to transition smoothly from global stop_machine to finer
grained synchronization between teardown callbacks and the other CPUs,
a new stop machine post function has been introduced to be executed
after the main one with IRQs still disabled while other CPUs can exit
stop_machine().

The teardown callback here simply performs IRQ disablement, which can
run concurrently with other CPUs.

Move it to post stop_machine() accordingly.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/cpu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 9735d6cd01d8..f8c8fbbd0628 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1275,7 +1275,7 @@ void clear_tasks_mm_cpumask(int cpu)
 static int take_cpu_down(void *_param)
 {
 	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
-	enum cpuhp_state target = max((int)st->target, CPUHP_AP_CLINT_TIMER_STARTING);
+	enum cpuhp_state target = max((int)st->target, CPUHP_AP_CSKY_TIMER_STARTING);
 	int err, cpu = smp_processor_id();
 
 	/* Ensure this CPU doesn't handle any more interrupts. */
@@ -1303,7 +1303,7 @@ static int take_cpu_down_post(void *_param)
 	enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
 	int cpu = smp_processor_id();
 
-	WARN_ON(st->state != CPUHP_AP_CLINT_TIMER_STARTING);
+	WARN_ON(st->state != CPUHP_AP_CSKY_TIMER_STARTING);
 	/*
 	 * Invoke the former CPU_DYING callbacks. DYING must not fail!
 	 */
-- 
2.53.0


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     [not found] <20261019130856.49711-1-frederic@kernel.org>
2026-10-19 13:08 ` [RFC PATCH 37/49] clocksource/drivers/c-sky: Move CPUHP_AP_CSKY_TIMER_STARTING post stop_machine() Frederic Weisbecker

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