cpu.h

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/*
 * include/linux/cpu.h - generic cpu definition
 *
 * This is mainly for topological representation. We define the 
 * basic 'struct cpu' here, which can be embedded in per-arch 
 * definitions of processors.
 *
 * Basic handling of the devices is done in drivers/base/cpu.c
 * and system devices are handled in drivers/base/sys.c. 
 *
 * CPUs are exported via sysfs in the class/cpu/devices/
 * directory. 
 */
#ifndef _LINUX_CPU_H_
#define _LINUX_CPU_H_

#include <linux/node.h>
#include <linux/compiler.h>
#include <linux/cpumask.h>

struct device;

struct cpu {
    int node_id;        /* The node which contains the CPU */
    int hotpluggable;   /* creates sysfs control file if hotpluggable */
    struct device dev;
};

extern int register_cpu(struct cpu *cpu, int num);
extern struct device *get_cpu_device(unsigned cpu);
extern bool cpu_is_hotpluggable(unsigned cpu);

extern int cpu_add_dev_attr(struct device_attribute *attr);
extern void cpu_remove_dev_attr(struct device_attribute *attr);

extern int cpu_add_dev_attr_group(struct attribute_group *attrs);
extern void cpu_remove_dev_attr_group(struct attribute_group *attrs);

#ifdef CONFIG_HOTPLUG_CPU
extern void unregister_cpu(struct cpu *cpu);
extern ssize_t arch_cpu_probe(const char *, size_t);
extern ssize_t arch_cpu_release(const char *, size_t);
#endif
struct notifier_block;

#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
extern int arch_cpu_uevent(struct device *dev, struct kobj_uevent_env *env);
extern ssize_t arch_print_cpu_modalias(struct device *dev,
                       struct device_attribute *attr,
                       char *bufptr);
#endif

/*
 * CPU notifier priorities.
 */
enum {
    /*
     * SCHED_ACTIVE marks a cpu which is coming up active during
     * CPU_ONLINE and CPU_DOWN_FAILED and must be the first
     * notifier.  CPUSET_ACTIVE adjusts cpuset according to
     * cpu_active mask right after SCHED_ACTIVE.  During
     * CPU_DOWN_PREPARE, SCHED_INACTIVE and CPUSET_INACTIVE are
     * ordered in the similar way.
     *
     * This ordering guarantees consistent cpu_active mask and
     * migration behavior to all cpu notifiers.
     */
    CPU_PRI_SCHED_ACTIVE    = INT_MAX,
    CPU_PRI_CPUSET_ACTIVE   = INT_MAX - 1,
    CPU_PRI_SCHED_INACTIVE  = INT_MIN + 1,
    CPU_PRI_CPUSET_INACTIVE = INT_MIN,

    /* migration should happen before other stuff but after perf */
    CPU_PRI_PERF        = 20,
    CPU_PRI_MIGRATION   = 10,
    /* bring up workqueues before normal notifiers and down after */
    CPU_PRI_WORKQUEUE_UP    = 5,
    CPU_PRI_WORKQUEUE_DOWN  = -5,
};

#define CPU_ONLINE      0x0002 /* CPU (unsigned)v is up */
#define CPU_UP_PREPARE      0x0003 /* CPU (unsigned)v coming up */
#define CPU_UP_CANCELED     0x0004 /* CPU (unsigned)v NOT coming up */
#define CPU_DOWN_PREPARE    0x0005 /* CPU (unsigned)v going down */
#define CPU_DOWN_FAILED     0x0006 /* CPU (unsigned)v NOT going down */
#define CPU_DEAD        0x0007 /* CPU (unsigned)v dead */
#define CPU_DYING       0x0008 /* CPU (unsigned)v not running any task,
                    * not handling interrupts, soon dead.
                    * Called on the dying cpu, interrupts
                    * are already disabled. Must not
                    * sleep, must not fail */
#define CPU_POST_DEAD       0x0009 /* CPU (unsigned)v dead, cpu_hotplug
                    * lock is dropped */
#define CPU_STARTING        0x000A /* CPU (unsigned)v soon running.
                    * Called on the new cpu, just before
                    * enabling interrupts. Must not sleep,
                    * must not fail */

/* Used for CPU hotplug events occurring while tasks are frozen due to a suspend
 * operation in progress
 */
#define CPU_TASKS_FROZEN    0x0010

#define CPU_ONLINE_FROZEN   (CPU_ONLINE | CPU_TASKS_FROZEN)
#define CPU_UP_PREPARE_FROZEN   (CPU_UP_PREPARE | CPU_TASKS_FROZEN)
#define CPU_UP_CANCELED_FROZEN  (CPU_UP_CANCELED | CPU_TASKS_FROZEN)
#define CPU_DOWN_PREPARE_FROZEN (CPU_DOWN_PREPARE | CPU_TASKS_FROZEN)
#define CPU_DOWN_FAILED_FROZEN  (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
#define CPU_DEAD_FROZEN     (CPU_DEAD | CPU_TASKS_FROZEN)
#define CPU_DYING_FROZEN    (CPU_DYING | CPU_TASKS_FROZEN)
#define CPU_STARTING_FROZEN (CPU_STARTING | CPU_TASKS_FROZEN)


#ifdef CONFIG_SMP
/* Need to know about CPUs going up/down? */
#if defined(CONFIG_HOTPLUG_CPU) || !defined(MODULE)
#define cpu_notifier(fn, pri) {                 \
    static struct notifier_block fn##_nb __cpuinitdata =    \
        { .notifier_call = fn, .priority = pri };   \
    register_cpu_notifier(&fn##_nb);            \
}
#else /* #if defined(CONFIG_HOTPLUG_CPU) || !defined(MODULE) */
#define cpu_notifier(fn, pri)   do { (void)(fn); } while (0)
#endif /* #else #if defined(CONFIG_HOTPLUG_CPU) || !defined(MODULE) */
#ifdef CONFIG_HOTPLUG_CPU
extern int register_cpu_notifier(struct notifier_block *nb);
extern void unregister_cpu_notifier(struct notifier_block *nb);
#else

#ifndef MODULE
extern int register_cpu_notifier(struct notifier_block *nb);
#else
static inline int register_cpu_notifier(struct notifier_block *nb)
{
    return 0;
}
#endif

static inline void unregister_cpu_notifier(struct notifier_block *nb)
{
}
#endif

int cpu_up(unsigned int cpu);
void notify_cpu_starting(unsigned int cpu);
extern void cpu_maps_update_begin(void);
extern void cpu_maps_update_done(void);

#else   /* CONFIG_SMP */

#define cpu_notifier(fn, pri)   do { (void)(fn); } while (0)

static inline int register_cpu_notifier(struct notifier_block *nb)
{
    return 0;
}

static inline void unregister_cpu_notifier(struct notifier_block *nb)
{
}

static inline void cpu_maps_update_begin(void)
{
}

static inline void cpu_maps_update_done(void)
{
}

#endif /* CONFIG_SMP */
extern struct bus_type cpu_subsys;

#ifdef CONFIG_HOTPLUG_CPU
/* Stop CPUs going up and down. */

extern void get_online_cpus(void);
extern void put_online_cpus(void);
#define hotcpu_notifier(fn, pri)    cpu_notifier(fn, pri)
#define register_hotcpu_notifier(nb)    register_cpu_notifier(nb)
#define unregister_hotcpu_notifier(nb)  unregister_cpu_notifier(nb)
void clear_tasks_mm_cpumask(int cpu);
int cpu_down(unsigned int cpu);

#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
extern void cpu_hotplug_driver_lock(void);
extern void cpu_hotplug_driver_unlock(void);
#else
static inline void cpu_hotplug_driver_lock(void)
{
}

static inline void cpu_hotplug_driver_unlock(void)
{
}
#endif

#else       /* CONFIG_HOTPLUG_CPU */

#define get_online_cpus()   do { } while (0)
#define put_online_cpus()   do { } while (0)
#define hotcpu_notifier(fn, pri)    do { (void)(fn); } while (0)
/* These aren't inline functions due to a GCC bug. */
#define register_hotcpu_notifier(nb)    ({ (void)(nb); 0; })
#define unregister_hotcpu_notifier(nb)  ({ (void)(nb); })
#endif      /* CONFIG_HOTPLUG_CPU */

#ifdef CONFIG_PM_SLEEP_SMP
extern int disable_nonboot_cpus(void);
extern void enable_nonboot_cpus(void);
#else /* !CONFIG_PM_SLEEP_SMP */
static inline int disable_nonboot_cpus(void) { return 0; }
static inline void enable_nonboot_cpus(void) {}
#endif /* !CONFIG_PM_SLEEP_SMP */

#endif /* _LINUX_CPU_H_ */