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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(pid: tid, clock: clock | CPUCLOCK_PERTHREAD_MASK);
28}
29
30static inline clockid_t fd_to_clockid(const int fd)
31{
32 return make_process_cpuclock(pid: (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, node: &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(head: ctmr->head, node: &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(ref: &tmr->rcuref))
237 posixtimer_free_timer(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
266

source code of linux/include/linux/posix-timers.h