posix-timers.h

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#ifndef _linux_POSIX_TIMERS_H
#define _linux_POSIX_TIMERS_H

#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sched.h>
#include <linux/timex.h>
#include <linux/alarmtimer.h>

union cpu_time_count {
    cputime_t cpu;
    unsigned long long sched;
};

struct cpu_timer_list {
    struct list_head entry;
    union cpu_time_count expires, incr;
    struct task_struct *task;
    int firing;
};

/*
 * Bit fields within a clockid:
 *
 * The most significant 29 bits hold either a pid or a file descriptor.
 *
 * Bit 2 indicates whether a cpu clock refers to a thread or a process.
 *
 * Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3.
 *
 * A clockid is invalid if bits 2, 1, and 0 are all set.
 */
#define CPUCLOCK_PID(clock)     ((pid_t) ~((clock) >> 3))
#define CPUCLOCK_PERTHREAD(clock) \
    (((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)

#define CPUCLOCK_PERTHREAD_MASK 4
#define CPUCLOCK_WHICH(clock)   ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
#define CPUCLOCK_CLOCK_MASK 3
#define CPUCLOCK_PROF       0
#define CPUCLOCK_VIRT       1
#define CPUCLOCK_SCHED      2
#define CPUCLOCK_MAX        3
#define CLOCKFD         CPUCLOCK_MAX
#define CLOCKFD_MASK        (CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK)

#define MAKE_PROCESS_CPUCLOCK(pid, clock) \
    ((~(clockid_t) (pid) << 3) | (clockid_t) (clock))
#define MAKE_THREAD_CPUCLOCK(tid, clock) \
    MAKE_PROCESS_CPUCLOCK((tid), (clock) | CPUCLOCK_PERTHREAD_MASK)

#define FD_TO_CLOCKID(fd)   ((~(clockid_t) (fd) << 3) | CLOCKFD)
#define CLOCKID_TO_FD(clk)  ((unsigned int) ~((clk) >> 3))

/* POSIX.1b interval timer structure. */
struct k_itimer {
    struct list_head list;      /* free/ allocate list */
    spinlock_t it_lock;
    clockid_t it_clock;     /* which timer type */
    timer_t it_id;          /* timer id */
    int it_overrun;         /* overrun on pending signal  */
    int it_overrun_last;        /* overrun on last delivered signal */
    int it_requeue_pending;     /* waiting to requeue this timer */
#define REQUEUE_PENDING 1
    int it_sigev_notify;        /* notify word of sigevent struct */
    struct signal_struct *it_signal;
    union {
        struct pid *it_pid; /* pid of process to send signal to */
        struct task_struct *it_process; /* for clock_nanosleep */
    };
    struct sigqueue *sigq;      /* signal queue entry. */
    union {
        struct {
            struct hrtimer timer;
            ktime_t interval;
        } real;
        struct cpu_timer_list cpu;
        struct {
            unsigned int clock;
            unsigned int node;
            unsigned long incr;
            unsigned long expires;
        } mmtimer;
        struct {
            struct alarm alarmtimer;
            ktime_t interval;
        } alarm;
        struct rcu_head rcu;
    } it;
};

struct k_clock {
    int (*clock_getres) (const clockid_t which_clock, struct timespec *tp);
    int (*clock_set) (const clockid_t which_clock,
              const struct timespec *tp);
    int (*clock_get) (const clockid_t which_clock, struct timespec * tp);
    int (*clock_adj) (const clockid_t which_clock, struct timex *tx);
    int (*timer_create) (struct k_itimer *timer);
    int (*nsleep) (const clockid_t which_clock, int flags,
               struct timespec *, struct timespec __user *);
    long (*nsleep_restart) (struct restart_block *restart_block);
    int (*timer_set) (struct k_itimer * timr, int flags,
              struct itimerspec * new_setting,
              struct itimerspec * old_setting);
    int (*timer_del) (struct k_itimer * timr);
#define TIMER_RETRY 1
    void (*timer_get) (struct k_itimer * timr,
               struct itimerspec * cur_setting);
};

extern struct k_clock clock_posix_cpu;
extern struct k_clock clock_posix_dynamic;

void posix_timers_register_clock(const clockid_t clock_id, struct k_clock *new_clock);

/* function to call to trigger timer event */
int posix_timer_event(struct k_itimer *timr, int si_private);

void posix_cpu_timer_schedule(struct k_itimer *timer);

void run_posix_cpu_timers(struct task_struct *task);
void posix_cpu_timers_exit(struct task_struct *task);
void posix_cpu_timers_exit_group(struct task_struct *task);

void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
               cputime_t *newval, cputime_t *oldval);

long clock_nanosleep_restart(struct restart_block *restart_block);

void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);

#endif