5142b1f388
Old realtime was used for both timers (where an accurate count of all ticks is needed) and the system time. In order to implement adjtime(2), these duties must be separated as changing the time of day by a small amount shouldn't affect timers in any way nor should it change the boot time. Following the naming of the clocks used by clock_gettime(2). The clock named 'realtime' will represent the best guess at the current wall clock time, and the clock named 'monotonic' will represent the absolute time the system has been running. Use monotonic for timers in kernel and in drivers. Use realtime for determining time of day, dates, etc. This commit simply renames realtime to monotonic and adds a new tick counter named realtime. There are no functional changes in this commit. It just lays the foundation for future work.
72 lines
2.5 KiB
C
72 lines
2.5 KiB
C
/* The kernel call implemented in this file:
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* m_type: SYS_SETALARM
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*
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* The parameters for this kernel call are:
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* m2_l1: ALRM_EXP_TIME (alarm's expiration time)
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* m2_i2: ALRM_ABS_TIME (expiration time is absolute?)
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* m2_l1: ALRM_TIME_LEFT (return seconds left of previous)
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*/
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#include "kernel/system.h"
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#include <minix/endpoint.h>
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#include <assert.h>
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#if USE_SETALARM
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static void cause_alarm(timer_t *tp);
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/*===========================================================================*
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* do_setalarm *
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*===========================================================================*/
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int do_setalarm(struct proc * caller, message * m_ptr)
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{
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/* A process requests a synchronous alarm, or wants to cancel its alarm. */
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long exp_time; /* expiration time for this alarm */
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int use_abs_time; /* use absolute or relative time */
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timer_t *tp; /* the process' timer structure */
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clock_t uptime; /* placeholder for current uptime */
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/* Extract shared parameters from the request message. */
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exp_time = m_ptr->ALRM_EXP_TIME; /* alarm's expiration time */
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use_abs_time = m_ptr->ALRM_ABS_TIME; /* flag for absolute time */
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if (! (priv(caller)->s_flags & SYS_PROC)) return(EPERM);
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/* Get the timer structure and set the parameters for this alarm. */
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tp = &(priv(caller)->s_alarm_timer);
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tmr_arg(tp)->ta_int = caller->p_endpoint;
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tp->tmr_func = cause_alarm;
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/* Return the ticks left on the previous alarm. */
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uptime = get_monotonic();
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if ((tp->tmr_exp_time != TMR_NEVER) && (uptime < tp->tmr_exp_time) ) {
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m_ptr->ALRM_TIME_LEFT = (tp->tmr_exp_time - uptime);
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} else {
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m_ptr->ALRM_TIME_LEFT = 0;
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}
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/* Finally, (re)set the timer depending on the expiration time. */
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if (exp_time == 0) {
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reset_timer(tp);
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} else {
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tp->tmr_exp_time = (use_abs_time) ? exp_time : exp_time + get_monotonic();
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set_timer(tp, tp->tmr_exp_time, tp->tmr_func);
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}
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return(OK);
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}
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/*===========================================================================*
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* cause_alarm *
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*===========================================================================*/
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static void cause_alarm(timer_t *tp)
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{
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/* Routine called if a timer goes off and the process requested a synchronous
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* alarm. The process number is stored in timer argument 'ta_int'. Notify that
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* process with a notification message from CLOCK.
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*/
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endpoint_t proc_nr_e = tmr_arg(tp)->ta_int; /* get process number */
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mini_notify(proc_addr(CLOCK), proc_nr_e); /* notify process */
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}
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#endif /* USE_SETALARM */
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