Line data    Source code

       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             : 
      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           0 :         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           0 :         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             :  * @pid:        Pointer to target task PID
      67             :  * @elist:      List head for the expiry list
      68             :  * @firing:     Timer is currently firing
      69             :  * @handling:   Pointer to the task which handles expiry
      70             :  */
      71             : struct cpu_timer {
      72             :         struct timerqueue_node          node;
      73             :         struct timerqueue_head          *head;
      74             :         struct pid                      *pid;
      75             :         struct list_head                elist;
      76             :         int                             firing;
      77             :         struct task_struct __rcu        *handling;
      78             : };
      79             : 
      80             : static inline bool cpu_timer_enqueue(struct timerqueue_head *head,
      81             :                                      struct cpu_timer *ctmr)
      82             : {
      83           0 :         ctmr->head = head;
      84           0 :         return timerqueue_add(head, &ctmr->node);
      85             : }
      86             : 
      87             : static inline bool cpu_timer_queued(struct cpu_timer *ctmr)
      88             : {
      89             :         return !!ctmr->head;
      90             : }
      91             : 
      92             : static inline bool cpu_timer_dequeue(struct cpu_timer *ctmr)
      93             : {
      94           0 :         if (cpu_timer_queued(ctmr)) {
      95           0 :                 timerqueue_del(ctmr->head, &ctmr->node);
      96           0 :                 ctmr->head = NULL;
      97             :                 return true;
      98             :         }
      99             :         return false;
     100             : }
     101             : 
     102             : static inline u64 cpu_timer_getexpires(struct cpu_timer *ctmr)
     103             : {
     104           0 :         return ctmr->node.expires;
     105             : }
     106             : 
     107             : static inline void cpu_timer_setexpires(struct cpu_timer *ctmr, u64 exp)
     108             : {
     109           0 :         ctmr->node.expires = exp;
     110             : }
     111             : 
     112             : /**
     113             :  * posix_cputimer_base - Container per posix CPU clock
     114             :  * @nextevt:            Earliest-expiration cache
     115             :  * @tqhead:             timerqueue head for cpu_timers
     116             :  */
     117             : struct posix_cputimer_base {
     118             :         u64                     nextevt;
     119             :         struct timerqueue_head  tqhead;
     120             : };
     121             : 
     122             : /**
     123             :  * posix_cputimers - Container for posix CPU timer related data
     124             :  * @bases:              Base container for posix CPU clocks
     125             :  * @timers_active:      Timers are queued.
     126             :  * @expiry_active:      Timer expiry is active. Used for
     127             :  *                      process wide timers to avoid multiple
     128             :  *                      task trying to handle expiry concurrently
     129             :  *
     130             :  * Used in task_struct and signal_struct
     131             :  */
     132             : struct posix_cputimers {
     133             :         struct posix_cputimer_base      bases[CPUCLOCK_MAX];
     134             :         unsigned int                    timers_active;
     135             :         unsigned int                    expiry_active;
     136             : };
     137             : 
     138             : /**
     139             :  * posix_cputimers_work - Container for task work based posix CPU timer expiry
     140             :  * @work:       The task work to be scheduled
     141             :  * @mutex:      Mutex held around expiry in context of this task work
     142             :  * @scheduled:  @work has been scheduled already, no further processing
     143             :  */
     144             : struct posix_cputimers_work {
     145             :         struct callback_head    work;
     146             :         struct mutex            mutex;
     147             :         unsigned int            scheduled;
     148             : };
     149             : 
     150             : static inline void posix_cputimers_init(struct posix_cputimers *pct)
     151             : {
     152         764 :         memset(pct, 0, sizeof(*pct));
     153         764 :         pct->bases[0].nextevt = U64_MAX;
     154         764 :         pct->bases[1].nextevt = U64_MAX;
     155         764 :         pct->bases[2].nextevt = U64_MAX;
     156             : }
     157             : 
     158             : void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit);
     159             : 
     160             : static inline void posix_cputimers_rt_watchdog(struct posix_cputimers *pct,
     161             :                                                u64 runtime)
     162             : {
     163           0 :         pct->bases[CPUCLOCK_SCHED].nextevt = runtime;
     164             : }
     165             : 
     166             : /* Init task static initializer */
     167             : #define INIT_CPU_TIMERBASE(b) {                                         \
     168             :         .nextevt        = U64_MAX,                                      \
     169             : }
     170             : 
     171             : #define INIT_CPU_TIMERBASES(b) {                                        \
     172             :         INIT_CPU_TIMERBASE(b[0]),                                       \
     173             :         INIT_CPU_TIMERBASE(b[1]),                                       \
     174             :         INIT_CPU_TIMERBASE(b[2]),                                       \
     175             : }
     176             : 
     177             : #define INIT_CPU_TIMERS(s)                                              \
     178             :         .posix_cputimers = {                                            \
     179             :                 .bases = INIT_CPU_TIMERBASES(s.posix_cputimers.bases),  \
     180             :         },
     181             : #else
     182             : struct posix_cputimers { };
     183             : struct cpu_timer { };
     184             : #define INIT_CPU_TIMERS(s)
     185             : static inline void posix_cputimers_init(struct posix_cputimers *pct) { }
     186             : static inline void posix_cputimers_group_init(struct posix_cputimers *pct,
     187             :                                               u64 cpu_limit) { }
     188             : #endif
     189             : 
     190             : #ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
     191             : void clear_posix_cputimers_work(struct task_struct *p);
     192             : void posix_cputimers_init_work(void);
     193             : #else
     194             : static inline void clear_posix_cputimers_work(struct task_struct *p) { }
     195             : static inline void posix_cputimers_init_work(void) { }
     196             : #endif
     197             : 
     198             : #define REQUEUE_PENDING 1
     199             : 
     200             : /**
     201             :  * struct k_itimer - POSIX.1b interval timer structure.
     202             :  * @list:               List head for binding the timer to signals->posix_timers
     203             :  * @t_hash:             Entry in the posix timer hash table
     204             :  * @it_lock:            Lock protecting the timer
     205             :  * @kclock:             Pointer to the k_clock struct handling this timer
     206             :  * @it_clock:           The posix timer clock id
     207             :  * @it_id:              The posix timer id for identifying the timer
     208             :  * @it_active:          Marker that timer is active
     209             :  * @it_overrun:         The overrun counter for pending signals
     210             :  * @it_overrun_last:    The overrun at the time of the last delivered signal
     211             :  * @it_requeue_pending: Indicator that timer waits for being requeued on
     212             :  *                      signal delivery
     213             :  * @it_sigev_notify:    The notify word of sigevent struct for signal delivery
     214             :  * @it_interval:        The interval for periodic timers
     215             :  * @it_signal:          Pointer to the creators signal struct
     216             :  * @it_pid:             The pid of the process/task targeted by the signal
     217             :  * @it_process:         The task to wakeup on clock_nanosleep (CPU timers)
     218             :  * @sigq:               Pointer to preallocated sigqueue
     219             :  * @it:                 Union representing the various posix timer type
     220             :  *                      internals.
     221             :  * @rcu:                RCU head for freeing the timer.
     222             :  */
     223             : struct k_itimer {
     224             :         struct list_head        list;
     225             :         struct hlist_node       t_hash;
     226             :         spinlock_t              it_lock;
     227             :         const struct k_clock    *kclock;
     228             :         clockid_t               it_clock;
     229             :         timer_t                 it_id;
     230             :         int                     it_active;
     231             :         s64                     it_overrun;
     232             :         s64                     it_overrun_last;
     233             :         int                     it_requeue_pending;
     234             :         int                     it_sigev_notify;
     235             :         ktime_t                 it_interval;
     236             :         struct signal_struct    *it_signal;
     237             :         union {
     238             :                 struct pid              *it_pid;
     239             :                 struct task_struct      *it_process;
     240             :         };
     241             :         struct sigqueue         *sigq;
     242             :         union {
     243             :                 struct {
     244             :                         struct hrtimer  timer;
     245             :                 } real;
     246             :                 struct cpu_timer        cpu;
     247             :                 struct {
     248             :                         struct alarm    alarmtimer;
     249             :                 } alarm;
     250             :         } it;
     251             :         struct rcu_head         rcu;
     252             : };
     253             : 
     254             : void run_posix_cpu_timers(void);
     255             : void posix_cpu_timers_exit(struct task_struct *task);
     256             : void posix_cpu_timers_exit_group(struct task_struct *task);
     257             : void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
     258             :                            u64 *newval, u64 *oldval);
     259             : 
     260             : int update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
     261             : 
     262             : void posixtimer_rearm(struct kernel_siginfo *info);
     263             : #endif