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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _linux_POSIX_TIMERS_H
#define _linux_POSIX_TIMERS_H
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/alarmtimer.h>
#include <linux/timerqueue.h>
#include <linux/task_work.h>
struct kernel_siginfo;
struct task_struct;
* 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_WHICH(clock) ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
#define CPUCLOCK_MAX 3
static inline clockid_t make_process_cpuclock(const unsigned int pid,
const clockid_t clock)
return ((~pid) << 3) | clock;
static inline clockid_t make_thread_cpuclock(const unsigned int tid,
const clockid_t clock)
return make_process_cpuclock(tid, clock | CPUCLOCK_PERTHREAD_MASK);
static inline clockid_t fd_to_clockid(const int fd)
return make_process_cpuclock((unsigned int) fd, CLOCKFD);
static inline int clockid_to_fd(const clockid_t clk)
return ~(clk >> 3);
* cpu_timer - Posix CPU timer representation for k_itimer
* @node: timerqueue node to queue in the task/sig
* @head: timerqueue head on which this timer is queued
* @task: Pointer to target task
* @elist: List head for the expiry list
* @firing: Timer is currently firing
struct cpu_timer {
struct timerqueue_node node;
struct timerqueue_head *head;
struct pid *pid;
struct list_head elist;
int firing;
static inline bool cpu_timer_enqueue(struct timerqueue_head *head,
struct cpu_timer *ctmr)
ctmr->head = head;
return timerqueue_add(head, &ctmr->node);
static inline bool cpu_timer_queued(struct cpu_timer *ctmr)
return !!ctmr->head;
static inline bool cpu_timer_dequeue(struct cpu_timer *ctmr)
if (cpu_timer_queued(ctmr)) {
timerqueue_del(ctmr->head, &ctmr->node);
ctmr->head = NULL;
return true;
return false;
static inline u64 cpu_timer_getexpires(struct cpu_timer *ctmr)
return ctmr->node.expires;
static inline void cpu_timer_setexpires(struct cpu_timer *ctmr, u64 exp)
ctmr->node.expires = exp;
* posix_cputimer_base - Container per posix CPU clock
* @nextevt: Earliest-expiration cache
* @tqhead: timerqueue head for cpu_timers
struct posix_cputimer_base {
u64 nextevt;
struct timerqueue_head tqhead;
* posix_cputimers - Container for posix CPU timer related data
* @bases: Base container for posix CPU clocks
* @timers_active: Timers are queued.
* @expiry_active: Timer expiry is active. Used for
* process wide timers to avoid multiple
* task trying to handle expiry concurrently
* Used in task_struct and signal_struct
struct posix_cputimers {
struct posix_cputimer_base bases[CPUCLOCK_MAX];
unsigned int timers_active;
unsigned int expiry_active;
* posix_cputimers_work - Container for task work based posix CPU timer expiry
* @work: The task work to be scheduled
* @scheduled: @work has been scheduled already, no further processing
struct posix_cputimers_work {
struct callback_head work;
unsigned int scheduled;
static inline void posix_cputimers_init(struct posix_cputimers *pct)
memset(pct, 0, sizeof(*pct));
pct->bases[0].nextevt = U64_MAX;
pct->bases[1].nextevt = U64_MAX;
pct->bases[2].nextevt = U64_MAX;
void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit);
static inline void posix_cputimers_rt_watchdog(struct posix_cputimers *pct,
u64 runtime)
pct->bases[CPUCLOCK_SCHED].nextevt = runtime;
/* Init task static initializer */
#define INIT_CPU_TIMERBASE(b) { \
.nextevt = U64_MAX, \
#define INIT_CPU_TIMERBASES(b) { \
#define INIT_CPU_TIMERS(s) \
.posix_cputimers = { \
.bases = INIT_CPU_TIMERBASES(s.posix_cputimers.bases), \
struct posix_cputimers { };
struct cpu_timer { };
#define INIT_CPU_TIMERS(s)
static inline void posix_cputimers_init(struct posix_cputimers *pct) { }
static inline void posix_cputimers_group_init(struct posix_cputimers *pct,
u64 cpu_limit) { }
void clear_posix_cputimers_work(struct task_struct *p);
void posix_cputimers_init_work(void);
static inline void clear_posix_cputimers_work(struct task_struct *p) { }
static inline void posix_cputimers_init_work(void) { }
* struct k_itimer - POSIX.1b interval timer structure.
* @list: List head for binding the timer to signals->posix_timers
* @t_hash: Entry in the posix timer hash table
* @it_lock: Lock protecting the timer
* @kclock: Pointer to the k_clock struct handling this timer
* @it_clock: The posix timer clock id
* @it_id: The posix timer id for identifying the timer
* @it_active: Marker that timer is active
* @it_overrun: The overrun counter for pending signals
* @it_overrun_last: The overrun at the time of the last delivered signal
* @it_requeue_pending: Indicator that timer waits for being requeued on
* signal delivery
* @it_sigev_notify: The notify word of sigevent struct for signal delivery
* @it_interval: The interval for periodic timers
* @it_signal: Pointer to the creators signal struct
* @it_pid: The pid of the process/task targeted by the signal
* @it_process: The task to wakeup on clock_nanosleep (CPU timers)
* @sigq: Pointer to preallocated sigqueue
* @it: Union representing the various posix timer type
* internals.
* @rcu: RCU head for freeing the timer.
struct k_itimer {
struct list_head list;
struct hlist_node t_hash;
spinlock_t it_lock;
const struct k_clock *kclock;
clockid_t it_clock;
timer_t it_id;
int it_active;
s64 it_overrun;
s64 it_overrun_last;
int it_requeue_pending;
int it_sigev_notify;
ktime_t it_interval;
struct signal_struct *it_signal;
union {
struct pid *it_pid;
struct task_struct *it_process;
struct sigqueue *sigq;
union {
struct {
struct hrtimer timer;
} real;
struct cpu_timer cpu;
struct {
struct alarm alarmtimer;
} alarm;
} it;
struct rcu_head rcu;
void run_posix_cpu_timers(void);
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,
u64 *newval, u64 *oldval);
void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
void posixtimer_rearm(struct kernel_siginfo *info);