1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _linux_POSIX_TIMERS_H
3 #define _linux_POSIX_TIMERS_H
4
5 #include <linux/spinlock.h>
6 #include <linux/list.h>
7 #include <linux/mutex.h>
8 #include <linux/alarmtimer.h>
9 #include <linux/timerqueue.h>
10 #include <linux/task_work.h>
11
12 struct kernel_siginfo;
13 struct task_struct;
14
15 /*
16 * Bit fields within a clockid:
17 *
18 * The most significant 29 bits hold either a pid or a file descriptor.
19 *
20 * Bit 2 indicates whether a cpu clock refers to a thread or a process.
21 *
22 * Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3.
23 *
24 * A clockid is invalid if bits 2, 1, and 0 are all set.
25 */
26 #define CPUCLOCK_PID(clock) ((pid_t) ~((clock) >> 3))
27 #define CPUCLOCK_PERTHREAD(clock) \
28 (((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)
29
30 #define CPUCLOCK_PERTHREAD_MASK 4
31 #define CPUCLOCK_WHICH(clock) ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
32 #define CPUCLOCK_CLOCK_MASK 3
33 #define CPUCLOCK_PROF 0
34 #define CPUCLOCK_VIRT 1
35 #define CPUCLOCK_SCHED 2
36 #define CPUCLOCK_MAX 3
37 #define CLOCKFD CPUCLOCK_MAX
38 #define CLOCKFD_MASK (CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK)
39
make_process_cpuclock(const unsigned int pid,const clockid_t clock)40 static inline clockid_t make_process_cpuclock(const unsigned int pid,
41 const clockid_t clock)
42 {
43 return ((~pid) << 3) | clock;
44 }
make_thread_cpuclock(const unsigned int tid,const clockid_t clock)45 static inline clockid_t make_thread_cpuclock(const unsigned int tid,
46 const clockid_t clock)
47 {
48 return make_process_cpuclock(tid, clock | CPUCLOCK_PERTHREAD_MASK);
49 }
50
fd_to_clockid(const int fd)51 static inline clockid_t fd_to_clockid(const int fd)
52 {
53 return make_process_cpuclock((unsigned int) fd, CLOCKFD);
54 }
55
clockid_to_fd(const clockid_t clk)56 static inline int clockid_to_fd(const clockid_t clk)
57 {
58 return ~(clk >> 3);
59 }
60
61 #ifdef CONFIG_POSIX_TIMERS
62
63 /**
64 * cpu_timer - Posix CPU timer representation for k_itimer
65 * @node: timerqueue node to queue in the task/sig
66 * @head: timerqueue head on which this timer is queued
67 * @pid: Pointer to target task PID
68 * @elist: List head for the expiry list
69 * @firing: Timer is currently firing
70 * @handling: Pointer to the task which handles expiry
71 */
72 struct cpu_timer {
73 struct timerqueue_node node;
74 struct timerqueue_head *head;
75 struct pid *pid;
76 struct list_head elist;
77 int firing;
78 struct task_struct __rcu *handling;
79 };
80
cpu_timer_enqueue(struct timerqueue_head * head,struct cpu_timer * ctmr)81 static inline bool cpu_timer_enqueue(struct timerqueue_head *head,
82 struct cpu_timer *ctmr)
83 {
84 ctmr->head = head;
85 return timerqueue_add(head, &ctmr->node);
86 }
87
cpu_timer_queued(struct cpu_timer * ctmr)88 static inline bool cpu_timer_queued(struct cpu_timer *ctmr)
89 {
90 return !!ctmr->head;
91 }
92
cpu_timer_dequeue(struct cpu_timer * ctmr)93 static inline bool cpu_timer_dequeue(struct cpu_timer *ctmr)
94 {
95 if (cpu_timer_queued(ctmr)) {
96 timerqueue_del(ctmr->head, &ctmr->node);
97 ctmr->head = NULL;
98 return true;
99 }
100 return false;
101 }
102
cpu_timer_getexpires(struct cpu_timer * ctmr)103 static inline u64 cpu_timer_getexpires(struct cpu_timer *ctmr)
104 {
105 return ctmr->node.expires;
106 }
107
cpu_timer_setexpires(struct cpu_timer * ctmr,u64 exp)108 static inline void cpu_timer_setexpires(struct cpu_timer *ctmr, u64 exp)
109 {
110 ctmr->node.expires = exp;
111 }
112
113 /**
114 * posix_cputimer_base - Container per posix CPU clock
115 * @nextevt: Earliest-expiration cache
116 * @tqhead: timerqueue head for cpu_timers
117 */
118 struct posix_cputimer_base {
119 u64 nextevt;
120 struct timerqueue_head tqhead;
121 };
122
123 /**
124 * posix_cputimers - Container for posix CPU timer related data
125 * @bases: Base container for posix CPU clocks
126 * @timers_active: Timers are queued.
127 * @expiry_active: Timer expiry is active. Used for
128 * process wide timers to avoid multiple
129 * task trying to handle expiry concurrently
130 *
131 * Used in task_struct and signal_struct
132 */
133 struct posix_cputimers {
134 struct posix_cputimer_base bases[CPUCLOCK_MAX];
135 unsigned int timers_active;
136 unsigned int expiry_active;
137 };
138
139 /**
140 * posix_cputimers_work - Container for task work based posix CPU timer expiry
141 * @work: The task work to be scheduled
142 * @mutex: Mutex held around expiry in context of this task work
143 * @scheduled: @work has been scheduled already, no further processing
144 */
145 struct posix_cputimers_work {
146 struct callback_head work;
147 struct mutex mutex;
148 unsigned int scheduled;
149 };
150
posix_cputimers_init(struct posix_cputimers * pct)151 static inline void posix_cputimers_init(struct posix_cputimers *pct)
152 {
153 memset(pct, 0, sizeof(*pct));
154 pct->bases[0].nextevt = U64_MAX;
155 pct->bases[1].nextevt = U64_MAX;
156 pct->bases[2].nextevt = U64_MAX;
157 }
158
159 void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit);
160
posix_cputimers_rt_watchdog(struct posix_cputimers * pct,u64 runtime)161 static inline void posix_cputimers_rt_watchdog(struct posix_cputimers *pct,
162 u64 runtime)
163 {
164 pct->bases[CPUCLOCK_SCHED].nextevt = runtime;
165 }
166
167 /* Init task static initializer */
168 #define INIT_CPU_TIMERBASE(b) { \
169 .nextevt = U64_MAX, \
170 }
171
172 #define INIT_CPU_TIMERBASES(b) { \
173 INIT_CPU_TIMERBASE(b[0]), \
174 INIT_CPU_TIMERBASE(b[1]), \
175 INIT_CPU_TIMERBASE(b[2]), \
176 }
177
178 #define INIT_CPU_TIMERS(s) \
179 .posix_cputimers = { \
180 .bases = INIT_CPU_TIMERBASES(s.posix_cputimers.bases), \
181 },
182 #else
183 struct posix_cputimers { };
184 struct cpu_timer { };
185 #define INIT_CPU_TIMERS(s)
posix_cputimers_init(struct posix_cputimers * pct)186 static inline void posix_cputimers_init(struct posix_cputimers *pct) { }
posix_cputimers_group_init(struct posix_cputimers * pct,u64 cpu_limit)187 static inline void posix_cputimers_group_init(struct posix_cputimers *pct,
188 u64 cpu_limit) { }
189 #endif
190
191 #ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
192 void clear_posix_cputimers_work(struct task_struct *p);
193 void posix_cputimers_init_work(void);
194 #else
clear_posix_cputimers_work(struct task_struct * p)195 static inline void clear_posix_cputimers_work(struct task_struct *p) { }
posix_cputimers_init_work(void)196 static inline void posix_cputimers_init_work(void) { }
197 #endif
198
199 #define REQUEUE_PENDING 1
200
201 /**
202 * struct k_itimer - POSIX.1b interval timer structure.
203 * @list: List head for binding the timer to signals->posix_timers
204 * @t_hash: Entry in the posix timer hash table
205 * @it_lock: Lock protecting the timer
206 * @kclock: Pointer to the k_clock struct handling this timer
207 * @it_clock: The posix timer clock id
208 * @it_id: The posix timer id for identifying the timer
209 * @it_active: Marker that timer is active
210 * @it_overrun: The overrun counter for pending signals
211 * @it_overrun_last: The overrun at the time of the last delivered signal
212 * @it_requeue_pending: Indicator that timer waits for being requeued on
213 * signal delivery
214 * @it_sigev_notify: The notify word of sigevent struct for signal delivery
215 * @it_interval: The interval for periodic timers
216 * @it_signal: Pointer to the creators signal struct
217 * @it_pid: The pid of the process/task targeted by the signal
218 * @it_process: The task to wakeup on clock_nanosleep (CPU timers)
219 * @sigq: Pointer to preallocated sigqueue
220 * @it: Union representing the various posix timer type
221 * internals.
222 * @rcu: RCU head for freeing the timer.
223 */
224 struct k_itimer {
225 struct list_head list;
226 struct hlist_node t_hash;
227 spinlock_t it_lock;
228 const struct k_clock *kclock;
229 clockid_t it_clock;
230 timer_t it_id;
231 int it_active;
232 s64 it_overrun;
233 s64 it_overrun_last;
234 int it_requeue_pending;
235 int it_sigev_notify;
236 ktime_t it_interval;
237 struct signal_struct *it_signal;
238 union {
239 struct pid *it_pid;
240 struct task_struct *it_process;
241 };
242 struct sigqueue *sigq;
243 union {
244 struct {
245 struct hrtimer timer;
246 } real;
247 struct cpu_timer cpu;
248 struct {
249 struct alarm alarmtimer;
250 } alarm;
251 } it;
252 struct rcu_head rcu;
253 };
254
255 void run_posix_cpu_timers(void);
256 void posix_cpu_timers_exit(struct task_struct *task);
257 void posix_cpu_timers_exit_group(struct task_struct *task);
258 void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
259 u64 *newval, u64 *oldval);
260
261 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
262
263 void posixtimer_rearm(struct kernel_siginfo *info);
264 #endif
265