kernel/arch/um/os-Linux/time.c

   1 /*
   2  * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
   3  * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
   4  * Copyright (C) 2012-2014 Cisco Systems
   5  * Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
   6  * Licensed under the GPL
   7  */
   8
   9 #include <stddef.h>
  10 #include <errno.h>
  11 #include <signal.h>
  12 #include <time.h>
  13 #include <sys/time.h>
  14 #include <kern_util.h>
  15 #include <os.h>
  16 #include <string.h>
  17 #include <timer-internal.h>
  18
  19 static timer_t event_high_res_timer = 0;
  20
  21 static inline long long timeval_to_ns(const struct timeval *tv)
  22 {
  23         return ((long long) tv->tv_sec * UM_NSEC_PER_SEC) +
  24                 tv->tv_usec * UM_NSEC_PER_USEC;
  25 }
  26
  27 static inline long long timespec_to_ns(const struct timespec *ts)
  28 {
  29         return ((long long) ts->tv_sec * UM_NSEC_PER_SEC) +
  30                 ts->tv_nsec;
  31 }
  32
  33 long long os_persistent_clock_emulation (void) {
  34         struct timespec realtime_tp;
  35
  36         clock_gettime(CLOCK_REALTIME, &realtime_tp);
  37         return timespec_to_ns(&realtime_tp);
  38 }
  39
  40 /**
  41  * os_timer_create() - create an new posix (interval) timer
  42  */
  43 int os_timer_create(void* timer) {
  44
  45         timer_t* t = timer;
  46
  47         if(t == NULL) {
  48                 t = &event_high_res_timer;
  49         }
  50
  51         if (timer_create(
  52                 CLOCK_MONOTONIC,
  53                 NULL,
  54                 t) == -1) {
  55                 return -1;
  56         }
  57         return 0;
  58 }
  59
  60 int os_timer_set_interval(void* timer, void* i)
  61 {
  62         struct itimerspec its;
  63         unsigned long long nsec;
  64         timer_t* t = timer;
  65         struct itimerspec* its_in = i;
  66
  67         if(t == NULL) {
  68                 t = &event_high_res_timer;
  69         }
  70
  71         nsec = UM_NSEC_PER_SEC / UM_HZ;
  72
  73         if(its_in != NULL) {
  74                 its.it_value.tv_sec = its_in->it_value.tv_sec;
  75                 its.it_value.tv_nsec = its_in->it_value.tv_nsec;
  76         } else {
  77                 its.it_value.tv_sec = 0;
  78                 its.it_value.tv_nsec = nsec;
  79         }
  80
  81         its.it_interval.tv_sec = 0;
  82         its.it_interval.tv_nsec = nsec;
  83
  84         if(timer_settime(*t, 0, &its, NULL) == -1) {
  85                 return -errno;
  86         }
  87
  88         return 0;
  89 }
  90
  91 /**
  92  * os_timer_remain() - returns the remaining nano seconds of the given interval
  93  *                     timer
  94  * Because this is the remaining time of an interval timer, which correspondends
  95  * to HZ, this value can never be bigger than one second. Just
  96  * the nanosecond part of the timer is returned.
  97  * The returned time is relative to the start time of the interval timer.
  98  * Return an negative value in an error case.
  99  */
 100 long os_timer_remain(void* timer)
 101 {
 102         struct itimerspec its;
 103         timer_t* t = timer;
 104
 105         if(t == NULL) {
 106                 t = &event_high_res_timer;
 107         }
 108
 109         if(timer_gettime(t, &its) == -1) {
 110                 return -errno;
 111         }
 112
 113         return its.it_value.tv_nsec;
 114 }
 115
 116 int os_timer_one_shot(int ticks)
 117 {
 118         struct itimerspec its;
 119         unsigned long long nsec;
 120         unsigned long sec;
 121
 122     nsec = (ticks + 1);
 123     sec = nsec / UM_NSEC_PER_SEC;
 124         nsec = nsec % UM_NSEC_PER_SEC;
 125
 126         its.it_value.tv_sec = nsec / UM_NSEC_PER_SEC;
 127         its.it_value.tv_nsec = nsec;
 128
 129         its.it_interval.tv_sec = 0;
 130         its.it_interval.tv_nsec = 0; // we cheat here
 131
 132         timer_settime(event_high_res_timer, 0, &its, NULL);
 133         return 0;
 134 }
 135
 136 /**
 137  * os_timer_disable() - disable the posix (interval) timer
 138  * Returns the remaining interval timer time in nanoseconds
 139  */
 140 long long os_timer_disable(void)
 141 {
 142         struct itimerspec its;
 143
 144         memset(&its, 0, sizeof(struct itimerspec));
 145         timer_settime(event_high_res_timer, 0, &its, &its);
 146
 147         return its.it_value.tv_sec * UM_NSEC_PER_SEC + its.it_value.tv_nsec;
 148 }
 149
 150 long long os_vnsecs(void)
 151 {
 152         struct timespec ts;
 153
 154         clock_gettime(CLOCK_PROCESS_CPUTIME_ID,&ts);
 155         return timespec_to_ns(&ts);
 156 }
 157
 158 long long os_nsecs(void)
 159 {
 160         struct timespec ts;
 161
 162         clock_gettime(CLOCK_MONOTONIC,&ts);
 163         return timespec_to_ns(&ts);
 164 }
 165
 166 /**
 167  * os_idle_sleep() - sleep for a given time of nsecs
 168  * @nsecs: nanoseconds to sleep
 169  */
 170 void os_idle_sleep(unsigned long long nsecs)
 171 {
 172         struct timespec ts;
 173
 174         if (nsecs <= 0) {
 175                 return;
 176         }
 177
 178         ts = ((struct timespec) {
 179                         .tv_sec  = nsecs / UM_NSEC_PER_SEC,
 180                         .tv_nsec = nsecs % UM_NSEC_PER_SEC
 181         });
 182
 183         /*
 184          * Relay the signal if clock_nanosleep is interrupted.
 185          */
 186         if (clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL)) {
 187                 deliver_alarm();
 188         }
 189 }