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Commit e937dd57 authored by Will Deacon's avatar Will Deacon
Browse files

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: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent d7a83d12

arch/arm64/kernel/debug-monitors.c

+6 −24
Original line number Diff line number Diff line
@@ -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);

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -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,