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 void cpu_timer_dequeue(struct cpu_timer *ctmr)
  86 {
  87         if (ctmr->head) {
  88                 timerqueue_del(ctmr->head, &ctmr->node);
  89                 ctmr->head = NULL;
  90         }
  91 }
  92
  93 static inline u64 cpu_timer_getexpires(struct cpu_timer *ctmr)
  94 {
  95         return ctmr->node.expires;
  96 }
  97
  98 static inline void cpu_timer_setexpires(struct cpu_timer *ctmr, u64 exp)
  99 {
 100         ctmr->node.expires = exp;
 101 }
 102
 103 /**
 104  * posix_cputimer_base - Container per posix CPU clock
 105  * @nextevt:            Earliest-expiration cache
 106  * @tqhead:             timerqueue head for cpu_timers
 107  */
 108 struct posix_cputimer_base {
 109         u64                     nextevt;
 110         struct timerqueue_head  tqhead;
 111 };
 112
 113 /**
 114  * posix_cputimers - Container for posix CPU timer related data
 115  * @bases:              Base container for posix CPU clocks
 116  * @timers_active:      Timers are queued.
 117  * @expiry_active:      Timer expiry is active. Used for
 118  *                      process wide timers to avoid multiple
 119  *                      task trying to handle expiry concurrently
 120  *
 121  * Used in task_struct and signal_struct
 122  */
 123 struct posix_cputimers {
 124         struct posix_cputimer_base      bases[CPUCLOCK_MAX];
 125         unsigned int                    timers_active;
 126         unsigned int                    expiry_active;
 127 };
 128
 129 /**
 130  * posix_cputimers_work - Container for task work based posix CPU timer expiry
 131  * @work:       The task work to be scheduled
 132  * @scheduled:  @work has been scheduled already, no further processing
 133  */
 134 struct posix_cputimers_work {
 135         struct callback_head    work;
 136         unsigned int            scheduled;
 137 };
 138
 139 static inline void posix_cputimers_init(struct posix_cputimers *pct)
 140 {
 141         memset(pct, 0, sizeof(*pct));
 142         pct->bases[0].nextevt = U64_MAX;
 143         pct->bases[1].nextevt = U64_MAX;
 144         pct->bases[2].nextevt = U64_MAX;
 145 }
 146
 147 void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit);
 148
 149 static inline void posix_cputimers_rt_watchdog(struct posix_cputimers *pct,
 150                                                u64 runtime)
 151 {
 152         pct->bases[CPUCLOCK_SCHED].nextevt = runtime;
 153 }
 154
 155 /* Init task static initializer */
 156 #define INIT_CPU_TIMERBASE(b) {                                         \
 157         .nextevt        = U64_MAX,                                      \
 158 }
 159
 160 #define INIT_CPU_TIMERBASES(b) {                                        \
 161         INIT_CPU_TIMERBASE(b[0]),                                       \
 162         INIT_CPU_TIMERBASE(b[1]),                                       \
 163         INIT_CPU_TIMERBASE(b[2]),                                       \
 164 }
 165
 166 #define INIT_CPU_TIMERS(s)                                              \
 167         .posix_cputimers = {                                            \
 168                 .bases = INIT_CPU_TIMERBASES(s.posix_cputimers.bases),  \
 169         },
 170 #else
 171 struct posix_cputimers { };
 172 struct cpu_timer { };
 173 #define INIT_CPU_TIMERS(s)
 174 static inline void posix_cputimers_init(struct posix_cputimers *pct) { }
 175 static inline void posix_cputimers_group_init(struct posix_cputimers *pct,
 176                                               u64 cpu_limit) { }
 177 #endif
 178
 179 #ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
 180 void posix_cputimers_init_work(void);
 181 #else
 182 static inline void posix_cputimers_init_work(void) { }
 183 #endif
 184
 185 #define REQUEUE_PENDING 1
 186
 187 /**
 188  * struct k_itimer - POSIX.1b interval timer structure.
 189  * @list:               List head for binding the timer to signals->posix_timers
 190  * @t_hash:             Entry in the posix timer hash table
 191  * @it_lock:            Lock protecting the timer
 192  * @kclock:             Pointer to the k_clock struct handling this timer
 193  * @it_clock:           The posix timer clock id
 194  * @it_id:              The posix timer id for identifying the timer
 195  * @it_active:          Marker that timer is active
 196  * @it_overrun:         The overrun counter for pending signals
 197  * @it_overrun_last:    The overrun at the time of the last delivered signal
 198  * @it_requeue_pending: Indicator that timer waits for being requeued on
 199  *                      signal delivery
 200  * @it_sigev_notify:    The notify word of sigevent struct for signal delivery
 201  * @it_interval:        The interval for periodic timers
 202  * @it_signal:          Pointer to the creators signal struct
 203  * @it_pid:             The pid of the process/task targeted by the signal
 204  * @it_process:         The task to wakeup on clock_nanosleep (CPU timers)
 205  * @sigq:               Pointer to preallocated sigqueue
 206  * @it:                 Union representing the various posix timer type
 207  *                      internals.
 208  * @rcu:                RCU head for freeing the timer.
 209  */
 210 struct k_itimer {
 211         struct list_head        list;
 212         struct hlist_node       t_hash;
 213         spinlock_t              it_lock;
 214         const struct k_clock    *kclock;
 215         clockid_t               it_clock;
 216         timer_t                 it_id;
 217         int                     it_active;
 218         s64                     it_overrun;
 219         s64                     it_overrun_last;
 220         int                     it_requeue_pending;
 221         int                     it_sigev_notify;
 222         ktime_t                 it_interval;
 223         struct signal_struct    *it_signal;
 224         union {
 225                 struct pid              *it_pid;
 226                 struct task_struct      *it_process;
 227         };
 228         struct sigqueue         *sigq;
 229         union {
 230                 struct {
 231                         struct hrtimer  timer;
 232                 } real;
 233                 struct cpu_timer        cpu;
 234                 struct {
 235                         struct alarm    alarmtimer;
 236                 } alarm;
 237         } it;
 238         struct rcu_head         rcu;
 239 };
 240
 241 void run_posix_cpu_timers(void);
 242 void posix_cpu_timers_exit(struct task_struct *task);
 243 void posix_cpu_timers_exit_group(struct task_struct *task);
 244 void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
 245                            u64 *newval, u64 *oldval);
 246
 247 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
 248
 249 void posixtimer_rearm(struct kernel_siginfo *info);
 250 #endif