[patch 23/66] xtensa: perf: Convert the hotplug notifier to state machine callbacks

[Anna-Maria Gleixner]

From: Sebastian Andrzej Siewior <bige...@linutronix.de>

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
Cc: Chris Zankel <ch...@zankel.net>
Cc: Max Filippov <jcmvb...@gmail.com>
Cc: linux-xte...@linux-xtensa.org
Signed-off-by: Anna-Maria Gleixner <anna-ma...@linutronix.de>
---
 arch/xtensa/kernel/perf_event.c |   26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

--- a/arch/xtensa/kernel/perf_event.c
+++ b/arch/xtensa/kernel/perf_event.c
@@ -404,7 +404,7 @@ static struct pmu xtensa_pmu = {
        .read = xtensa_pmu_read,
 };
 
-static void xtensa_pmu_setup(void)
+static int xtensa_pmu_setup(int cpu)
 {
        unsigned i;
 
@@ -413,21 +413,7 @@ static void xtensa_pmu_setup(void)
                set_er(0, XTENSA_PMU_PMCTRL(i));
                set_er(get_er(XTENSA_PMU_PMSTAT(i)), XTENSA_PMU_PMSTAT(i));
        }
-}
-
-static int xtensa_pmu_notifier(struct notifier_block *self,
-                              unsigned long action, void *data)
-{
-       switch (action & ~CPU_TASKS_FROZEN) {
-       case CPU_STARTING:
-               xtensa_pmu_setup();
-               break;
-
-       default:
-               break;
-       }
-
-       return NOTIFY_OK;
+       return 0;
 }
 
 static int __init xtensa_pmu_init(void)
@@ -435,7 +421,13 @@ static int __init xtensa_pmu_init(void)
        int ret;
        int irq = irq_create_mapping(NULL, XCHAL_PROFILING_INTERRUPT);
 
-       perf_cpu_notifier(xtensa_pmu_notifier);
+       ret = cpuhp_setup_state(CPUHP_AP_PERF_XTENSA_STARTING,
+                               "AP_PERF_XTENSA_STARTING", xtensa_pmu_setup,
+                               NULL);
+       if (ret) {
+               pr_err("xtensa_pmu: failed to register CPU-hotplug.\n");
+               return ret;
+       }
 #if XTENSA_FAKE_NMI
        enable_irq(irq);
 #else