cpu.c

/* CPU control.
 * (C) 2001, 2002, 2003, 2004 Rusty Russell
 *
 * This code is licenced under the GPL.
 */
#include <linux/proc_fs.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/sched.h>
#include <linux/unistd.h>
#include <linux/cpu.h>
#include <linux/oom.h>
#include <linux/rcupdate.h>
#include <linux/export.h>
#include <linux/bug.h>
#include <linux/kthread.h>
#include <linux/stop_machine.h>
#include <linux/mutex.h>
#include <linux/gfp.h>
#include <linux/suspend.h>
#include <linux/lockdep.h>
#include <linux/tick.h>
#include <linux/irq.h>

#include <trace/events/power.h>
#define CREATE_TRACE_POINTS
#include <trace/events/cpuhp.h>

#include "smpboot.h"

/**
 * cpuhp_cpu_state - Per cpu hotplug state storage
 * @state:	The current cpu state
 * @target:	The target state
 */
struct cpuhp_cpu_state {
	enum cpuhp_state	state;
	enum cpuhp_state	target;
};

static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state);

/**
 * cpuhp_step - Hotplug state machine step
 * @name:	Name of the step
 * @startup:	Startup function of the step
 * @teardown:	Teardown function of the step
 * @skip_onerr:	Do not invoke the functions on error rollback
 *		Will go away once the notifiers	are gone
 */
struct cpuhp_step {
	const char	*name;
	int		(*startup)(unsigned int cpu);
	int		(*teardown)(unsigned int cpu);
	bool		skip_onerr;
};

static struct cpuhp_step cpuhp_bp_states[];

/**
 * cpuhp_invoke_callback _ Invoke the callbacks for a given state
 * @cpu:	The cpu for which the callback should be invoked
 * @step:	The step in the state machine
 * @cb:		The callback function to invoke
 *
 * Called from cpu hotplug and from the state register machinery
 */
static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state step,
				 int (*cb)(unsigned int))