arm64: debug: convert OS lock CPU hotplug notifier to new infrastructure

The arm64 debug monitor initialisation code uses a CPU hotplug notifier
to clear the OS lock when CPUs come online.

This patch converts the code to the new hotplug mechanism.

Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 2751ff9..3082192 100644 (file)
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -132,36 +132,18 @@ NOKPROBE_SYMBOL(disable_debug_monitors);
 /*
  * OS lock clearing.
  */
-static void clear_os_lock(void *unused)
+static int clear_os_lock(unsigned int cpu)
 {
        asm volatile("msr oslar_el1, %0" : : "r" (0));
+       isb();
+       return 0;
 }
 
-static int os_lock_notify(struct notifier_block *self,
-                                   unsigned long action, void *data)
-{
-       if ((action & ~CPU_TASKS_FROZEN) == CPU_ONLINE)
-               clear_os_lock(NULL);
-       return NOTIFY_OK;
-}
-
-static struct notifier_block os_lock_nb = {
-       .notifier_call = os_lock_notify,
-};
-
 static int debug_monitors_init(void)
 {
-       cpu_notifier_register_begin();
-
-       /* Clear the OS lock. */
-       on_each_cpu(clear_os_lock, NULL, 1);
-       isb();
-
-       /* Register hotplug handler. */
-       __register_cpu_notifier(&os_lock_nb);
-
-       cpu_notifier_register_done();
-       return 0;
+       return cpuhp_setup_state(CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
+                                "CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING",
+                                clear_os_lock, NULL);
 }
 postcore_initcall(debug_monitors_init);
 

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 3758fe6..8c999a2 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -45,6 +45,7 @@ enum cpuhp_state {
        CPUHP_AP_PERF_METAG_STARTING,
        CPUHP_AP_MIPS_OP_LOONGSON3_STARTING,
        CPUHP_AP_ARM_VFP_STARTING,
+       CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
        CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
        CPUHP_AP_PERF_ARM_STARTING,
        CPUHP_AP_ARM_L2X0_STARTING,