posix-timers.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _linux_POSIX_TIMERS_H
  3#define _linux_POSIX_TIMERS_H
  4
  5#include <linux/alarmtimer.h>
  6#include <linux/list.h>
  7#include <linux/mutex.h>
  8#include <linux/pid.h>
  9#include <linux/posix-timers_types.h>
 10#include <linux/rcuref.h>
 11#include <linux/spinlock.h>
 12#include <linux/timerqueue.h>
 13
 14struct kernel_siginfo;
 15struct task_struct;
 16struct sigqueue;
 17struct k_itimer;
 18
 19static inline clockid_t make_process_cpuclock(const unsigned int pid,
 20		const clockid_t clock)
 21{
 22	return ((~pid) << 3) | clock;
 23}
 24static inline clockid_t make_thread_cpuclock(const unsigned int tid,
 25		const clockid_t clock)
 26{
 27	return make_process_cpuclock(tid, clock | CPUCLOCK_PERTHREAD_MASK);
 28}
 29
 30static inline clockid_t fd_to_clockid(const int fd)
 31{
 32	return make_process_cpuclock((unsigned int) fd, CLOCKFD);
 33}
 34
 35static inline int clockid_to_fd(const clockid_t clk)
 36{
 37	return ~(clk >> 3);
 38}
 39
 40static inline bool clockid_aux_valid(clockid_t id)
 41{
 42	return IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS) && id >= CLOCK_AUX && id <= CLOCK_AUX_LAST;
 43}
 44
 45#ifdef CONFIG_POSIX_TIMERS
 46
 47#include <linux/signal_types.h>
 48
 49/**
 50 * cpu_timer - Posix CPU timer representation for k_itimer
 51 * @node:	timerqueue node to queue in the task/sig
 52 * @head:	timerqueue head on which this timer is queued
 53 * @pid:	Pointer to target task PID
 54 * @elist:	List head for the expiry list
 55 * @firing:	Timer is currently firing
 56 * @nanosleep:	Timer is used for nanosleep and is not a regular posix-timer
 57 * @handling:	Pointer to the task which handles expiry
 58 */
 59struct cpu_timer {
 60	struct timerqueue_node		node;
 61	struct timerqueue_head		*head;
 62	struct pid			*pid;
 63	struct list_head		elist;
 64	bool				firing;
 65	bool				nanosleep;
 66	struct task_struct __rcu	*handling;
 67};
 68
 69static inline bool cpu_timer_enqueue(struct timerqueue_head *head,
 70				     struct cpu_timer *ctmr)
 71{
 72	ctmr->head = head;
 73	return timerqueue_add(head, &ctmr->node);
 74}
 75
 76static inline bool cpu_timer_queued(struct cpu_timer *ctmr)
 77{
 78	return !!ctmr->head;
 79}
 80
 81static inline bool cpu_timer_dequeue(struct cpu_timer *ctmr)
 82{
 83	if (cpu_timer_queued(ctmr)) {
 84		timerqueue_del(ctmr->head, &ctmr->node);
 85		ctmr->head = NULL;
 86		return true;
 87	}
 88	return false;
 89}
 90
 91static inline u64 cpu_timer_getexpires(struct cpu_timer *ctmr)
 92{
 93	return ctmr->node.expires;
 94}
 95
 96static inline void cpu_timer_setexpires(struct cpu_timer *ctmr, u64 exp)
 97{
 98	ctmr->node.expires = exp;
 99}
100
101static inline void posix_cputimers_init(struct posix_cputimers *pct)
102{
103	memset(pct, 0, sizeof(*pct));
104	pct->bases[0].nextevt = U64_MAX;
105	pct->bases[1].nextevt = U64_MAX;
106	pct->bases[2].nextevt = U64_MAX;
107}
108
109void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit);
110
111static inline void posix_cputimers_rt_watchdog(struct posix_cputimers *pct,
112					       u64 runtime)
113{
114	pct->bases[CPUCLOCK_SCHED].nextevt = runtime;
115}
116
117void posixtimer_rearm_itimer(struct task_struct *p);
118bool posixtimer_init_sigqueue(struct sigqueue *q);
119void posixtimer_send_sigqueue(struct k_itimer *tmr);
120bool posixtimer_deliver_signal(struct kernel_siginfo *info, struct sigqueue *timer_sigq);
121void posixtimer_free_timer(struct k_itimer *timer);
122long posixtimer_create_prctl(unsigned long ctrl);
123
124/* Init task static initializer */
125#define INIT_CPU_TIMERBASE(b) {						\
126	.nextevt	= U64_MAX,					\
127}
128
129#define INIT_CPU_TIMERBASES(b) {					\
130	INIT_CPU_TIMERBASE(b[0]),					\
131	INIT_CPU_TIMERBASE(b[1]),					\
132	INIT_CPU_TIMERBASE(b[2]),					\
133}
134
135#define INIT_CPU_TIMERS(s)						\
136	.posix_cputimers = {						\
137		.bases = INIT_CPU_TIMERBASES(s.posix_cputimers.bases),	\
138	},
139#else
140struct cpu_timer { };
141#define INIT_CPU_TIMERS(s)
142static inline void posix_cputimers_init(struct posix_cputimers *pct) { }
143static inline void posix_cputimers_group_init(struct posix_cputimers *pct,
144					      u64 cpu_limit) { }
145static inline void posixtimer_rearm_itimer(struct task_struct *p) { }
146static inline bool posixtimer_deliver_signal(struct kernel_siginfo *info,
147					     struct sigqueue *timer_sigq) { return false; }
148static inline void posixtimer_free_timer(struct k_itimer *timer) { }
149static inline long posixtimer_create_prctl(unsigned long ctrl) { return -EINVAL; }
150#endif
151
152#ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
153void clear_posix_cputimers_work(struct task_struct *p);
154void posix_cputimers_init_work(void);
155#else
156static inline void clear_posix_cputimers_work(struct task_struct *p) { }
157static inline void posix_cputimers_init_work(void) { }
158#endif
159
160/**
161 * struct k_itimer - POSIX.1b interval timer structure.
162 * @list:		List node for binding the timer to tsk::signal::posix_timers
163 * @ignored_list:	List node for tracking ignored timers in tsk::signal::ignored_posix_timers
164 * @t_hash:		Entry in the posix timer hash table
165 * @it_lock:		Lock protecting the timer
166 * @kclock:		Pointer to the k_clock struct handling this timer
167 * @it_clock:		The posix timer clock id
168 * @it_id:		The posix timer id for identifying the timer
169 * @it_status:		The status of the timer
170 * @it_sig_periodic:	The periodic status at signal delivery
171 * @it_overrun:		The overrun counter for pending signals
172 * @it_overrun_last:	The overrun at the time of the last delivered signal
173 * @it_signal_seq:	Sequence count to control signal delivery
174 * @it_sigqueue_seq:	The sequence count at the point where the signal was queued
175 * @it_sigev_notify:	The notify word of sigevent struct for signal delivery
176 * @it_interval:	The interval for periodic timers
177 * @it_signal:		Pointer to the creators signal struct
178 * @it_pid:		The pid of the process/task targeted by the signal
179 * @it_process:		The task to wakeup on clock_nanosleep (CPU timers)
180 * @rcuref:		Reference count for life time management
181 * @sigq:		Embedded sigqueue
182 * @it:			Union representing the various posix timer type
183 *			internals.
184 * @rcu:		RCU head for freeing the timer.
185 */
186struct k_itimer {
187	/* 1st cacheline contains read-mostly fields */
188	struct hlist_node	t_hash;
189	struct hlist_node	list;
190	timer_t			it_id;
191	clockid_t		it_clock;
192	int			it_sigev_notify;
193	enum pid_type		it_pid_type;
194	struct signal_struct	*it_signal;
195	const struct k_clock	*kclock;
196
197	/* 2nd cacheline and above contain fields which are modified regularly */
198	spinlock_t		it_lock;
199	int			it_status;
200	bool			it_sig_periodic;
201	s64			it_overrun;
202	s64			it_overrun_last;
203	unsigned int		it_signal_seq;
204	unsigned int		it_sigqueue_seq;
205	ktime_t			it_interval;
206	struct hlist_node	ignored_list;
207	union {
208		struct pid		*it_pid;
209		struct task_struct	*it_process;
210	};
211	struct sigqueue		sigq;
212	rcuref_t		rcuref;
213	union {
214		struct {
215			struct hrtimer	timer;
216		} real;
217		struct cpu_timer	cpu;
218		struct {
219			struct alarm	alarmtimer;
220		} alarm;
221	} it;
222	struct rcu_head		rcu;
223} ____cacheline_aligned_in_smp;
224
225void run_posix_cpu_timers(void);
226void posix_cpu_timers_exit(struct task_struct *task);
227void posix_cpu_timers_exit_group(struct task_struct *task);
228void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
229			   u64 *newval, u64 *oldval);
230
231int update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
232
233#ifdef CONFIG_POSIX_TIMERS
234static inline void posixtimer_putref(struct k_itimer *tmr)
235{
236	if (rcuref_put(&tmr->rcuref))
237		posixtimer_free_timer(tmr);
238}
239
240static inline void posixtimer_sigqueue_getref(struct sigqueue *q)
241{
242	struct k_itimer *tmr = container_of(q, struct k_itimer, sigq);
243
244	WARN_ON_ONCE(!rcuref_get(&tmr->rcuref));
245}
246
247static inline void posixtimer_sigqueue_putref(struct sigqueue *q)
248{
249	struct k_itimer *tmr = container_of(q, struct k_itimer, sigq);
250
251	posixtimer_putref(tmr);
252}
253
254static inline bool posixtimer_valid(const struct k_itimer *timer)
255{
256	unsigned long val = (unsigned long)timer->it_signal;
257
258	return !(val & 0x1UL);
259}
260#else  /* CONFIG_POSIX_TIMERS */
261static inline void posixtimer_sigqueue_getref(struct sigqueue *q) { }
262static inline void posixtimer_sigqueue_putref(struct sigqueue *q) { }
263#endif /* !CONFIG_POSIX_TIMERS */
264
265#endif