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