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
  10 struct kernel_siginfo;
  11 struct task_struct;
  12
  13 /*
  14  * Bit fields within a clockid:
  15  *
  16  * The most significant 29 bits hold either a pid or a file descriptor.
  17  *
  18  * Bit 2 indicates whether a cpu clock refers to a thread or a process.
  19  *
  20  * Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3.
  21  *
  22  * A clockid is invalid if bits 2, 1, and 0 are all set.
  23  */
  24 #define CPUCLOCK_PID(clock)             ((pid_t) ~((clock) >> 3))
  25 #define CPUCLOCK_PERTHREAD(clock) \
  26         (((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)
  27
  28 #define CPUCLOCK_PERTHREAD_MASK 4
  29 #define CPUCLOCK_WHICH(clock)   ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
  30 #define CPUCLOCK_CLOCK_MASK     3
  31 #define CPUCLOCK_PROF           0
  32 #define CPUCLOCK_VIRT           1
  33 #define CPUCLOCK_SCHED          2
  34 #define CPUCLOCK_MAX            3
  35 #define CLOCKFD                 CPUCLOCK_MAX
  36 #define CLOCKFD_MASK            (CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK)
  37
  38 static inline clockid_t make_process_cpuclock(const unsigned int pid,
  39                 const clockid_t clock)
  40 {
  41         return ((~pid) << 3) | clock;
  42 }
  43 static inline clockid_t make_thread_cpuclock(const unsigned int tid,
  44                 const clockid_t clock)
  45 {
  46         return make_process_cpuclock(tid, clock | CPUCLOCK_PERTHREAD_MASK);
  47 }
  48
  49 static inline clockid_t fd_to_clockid(const int fd)
  50 {
  51         return make_process_cpuclock((unsigned int) fd, CLOCKFD);
  52 }
  53
  54 static inline int clockid_to_fd(const clockid_t clk)
  55 {
  56         return ~(clk >> 3);
  57 }
  58
  59 #ifdef CONFIG_POSIX_TIMERS
  60
  61 /**
  62  * cpu_timer - Posix CPU timer representation for k_itimer
  63  * @node:       timerqueue node to queue in the task/sig
  64  * @head:       timerqueue head on which this timer is queued
  65  * @task:       Pointer to target task
  66  * @elist:      List head for the expiry list
  67  * @firing:     Timer is currently firing
  68  */
  69 struct cpu_timer {
  70         struct timerqueue_node  node;
  71         struct timerqueue_head  *head;
  72         struct task_struct      *task;
  73         struct list_head        elist;
  74         int                     firing;
  75 };
  76
  77 static inline bool cpu_timer_enqueue(struct timerqueue_head *head,
  78                                      struct cpu_timer *ctmr)
  79 {
  80         ctmr->head = head;
  81         return timerqueue_add(head, &ctmr->node);
  82 }
  83
  84 static inline void cpu_timer_dequeue(struct cpu_timer *ctmr)
  85 {
  86         if (ctmr->head) {
  87                 timerqueue_del(ctmr->head, &ctmr->node);
  88                 ctmr->head = NULL;
  89         }
  90 }
  91
  92 static inline u64 cpu_timer_getexpires(struct cpu_timer *ctmr)
  93 {
  94         return ctmr->node.expires;
  95 }
  96
  97 static inline void cpu_timer_setexpires(struct cpu_timer *ctmr, u64 exp)
  98 {
  99         ctmr->node.expires = exp;
 100 }
 101
 102 /**
 103  * posix_cputimer_base - Container per posix CPU clock
 104  * @nextevt:            Earliest-expiration cache
 105  * @tqhead:             timerqueue head for cpu_timers
 106  */
 107 struct posix_cputimer_base {
 108         u64                     nextevt;
 109         struct timerqueue_head  tqhead;
 110 };
 111
 112 /**
 113  * posix_cputimers - Container for posix CPU timer related data
 114  * @bases:              Base container for posix CPU clocks
 115  * @timers_active:      Timers are queued.
 116  * @expiry_active:      Timer expiry is active. Used for
 117  *                      process wide timers to avoid multiple
 118  *                      task trying to handle expiry concurrently
 119  *
 120  * Used in task_struct and signal_struct
 121  */
 122 struct posix_cputimers {
 123         struct posix_cputimer_base      bases[CPUCLOCK_MAX];
 124         unsigned int                    timers_active;
 125         unsigned int                    expiry_active;
 126 };
 127
 128 static inline void posix_cputimers_init(struct posix_cputimers *pct)
 129 {
 130         memset(pct, 0, sizeof(*pct));
 131         pct->bases[0].nextevt = U64_MAX;
 132         pct->bases[1].nextevt = U64_MAX;
 133         pct->bases[2].nextevt = U64_MAX;
 134 }
 135
 136 void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit);
 137
 138 static inline void posix_cputimers_rt_watchdog(struct posix_cputimers *pct,
 139                                                u64 runtime)
 140 {
 141         pct->bases[CPUCLOCK_SCHED].nextevt = runtime;
 142 }
 143
 144 /* Init task static initializer */
 145 #define INIT_CPU_TIMERBASE(b) {                                         \
 146         .nextevt        = U64_MAX,                                      \
 147 }
 148
 149 #define INIT_CPU_TIMERBASES(b) {                                        \
 150         INIT_CPU_TIMERBASE(b[0]),                                       \
 151         INIT_CPU_TIMERBASE(b[1]),                                       \
 152         INIT_CPU_TIMERBASE(b[2]),                                       \
 153 }
 154
 155 #define INIT_CPU_TIMERS(s)                                              \
 156         .posix_cputimers = {                                            \
 157                 .bases = INIT_CPU_TIMERBASES(s.posix_cputimers.bases),  \
 158         },
 159 #else
 160 struct posix_cputimers { };
 161 struct cpu_timer { };
 162 #define INIT_CPU_TIMERS(s)
 163 static inline void posix_cputimers_init(struct posix_cputimers *pct) { }
 164 static inline void posix_cputimers_group_init(struct posix_cputimers *pct,
 165                                               u64 cpu_limit) { }
 166 #endif
 167
 168 #define REQUEUE_PENDING 1
 169
 170 /**
 171  * struct k_itimer - POSIX.1b interval timer structure.
 172  * @list:               List head for binding the timer to signals->posix_timers
 173  * @t_hash:             Entry in the posix timer hash table
 174  * @it_lock:            Lock protecting the timer
 175  * @kclock:             Pointer to the k_clock struct handling this timer
 176  * @it_clock:           The posix timer clock id
 177  * @it_id:              The posix timer id for identifying the timer
 178  * @it_active:          Marker that timer is active
 179  * @it_overrun:         The overrun counter for pending signals
 180  * @it_overrun_last:    The overrun at the time of the last delivered signal
 181  * @it_requeue_pending: Indicator that timer waits for being requeued on
 182  *                      signal delivery
 183  * @it_sigev_notify:    The notify word of sigevent struct for signal delivery
 184  * @it_interval:        The interval for periodic timers
 185  * @it_signal:          Pointer to the creators signal struct
 186  * @it_pid:             The pid of the process/task targeted by the signal
 187  * @it_process:         The task to wakeup on clock_nanosleep (CPU timers)
 188  * @sigq:               Pointer to preallocated sigqueue
 189  * @it:                 Union representing the various posix timer type
 190  *                      internals.
 191  * @rcu:                RCU head for freeing the timer.
 192  */
 193 struct k_itimer {
 194         struct list_head        list;
 195         struct hlist_node       t_hash;
 196         spinlock_t              it_lock;
 197         const struct k_clock    *kclock;
 198         clockid_t               it_clock;
 199         timer_t                 it_id;
 200         int                     it_active;
 201         s64                     it_overrun;
 202         s64                     it_overrun_last;
 203         int                     it_requeue_pending;
 204         int                     it_sigev_notify;
 205         ktime_t                 it_interval;
 206         struct signal_struct    *it_signal;
 207         union {
 208                 struct pid              *it_pid;
 209                 struct task_struct      *it_process;
 210         };
 211         struct sigqueue         *sigq;
 212         union {
 213                 struct {
 214                         struct hrtimer  timer;
 215                 } real;
 216                 struct cpu_timer        cpu;
 217                 struct {
 218                         struct alarm    alarmtimer;
 219                 } alarm;
 220         } it;
 221         struct rcu_head         rcu;
 222 };
 223
 224 void run_posix_cpu_timers(void);
 225 void posix_cpu_timers_exit(struct task_struct *task);
 226 void posix_cpu_timers_exit_group(struct task_struct *task);
 227 void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
 228                            u64 *newval, u64 *oldval);
 229
 230 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
 231
 232 void posixtimer_rearm(struct kernel_siginfo *info);
 233 #endif