diff options
| -rw-r--r-- | arch/riscv64/kernel/timer.c | 5 | ||||
| -rw-r--r-- | include/arch/timer.h | 13 | ||||
| -rw-r--r-- | src/timer.c | 31 |
3 files changed, 47 insertions, 2 deletions
diff --git a/arch/riscv64/kernel/timer.c b/arch/riscv64/kernel/timer.c index c7752f8..e9e509d 100644 --- a/arch/riscv64/kernel/timer.c +++ b/arch/riscv64/kernel/timer.c @@ -24,6 +24,11 @@ void set_timer(ticks_t ticks) sbi_set_timer(ticks); } +void clear_timer() +{ + sbi_set_timer(-1); +} + /** * Get current ticks. * diff --git a/include/arch/timer.h b/include/arch/timer.h index 8b832c9..8f235e6 100644 --- a/include/arch/timer.h +++ b/include/arch/timer.h @@ -30,6 +30,12 @@ ticks_t stat_timer(const void *fdt); /** * Set up timer interrupt for absolute ticks. + * At least currently assumes there is only one global timer, the kernel will + * ensure that the timer is scheduled to handle events in order. + * + * When setting a new timer, the current timer (if one is set) will + * not trigger an interrupt. For instance, if called from the interrupt handler + * of the existing interrupt, it won't re-trigger. * * @param ticks Time point for timer to trigger. * \todo Should maybe be stat_t? @@ -37,6 +43,13 @@ ticks_t stat_timer(const void *fdt); void set_timer(ticks_t ticks); /** + * Stop the timer interrupts from happening altogether. Mainly called during + * init to avoid spurious interrupts and when all userspace timers have been + * handled. + */ +void clear_timer(); + +/** * Get current ticks. * * @return Current tick count. diff --git a/src/timer.c b/src/timer.c index 5583cd3..5b3ac86 100644 --- a/src/timer.c +++ b/src/timer.c @@ -73,6 +73,7 @@ static struct sp_root *__cpu_timers() void init_timer(const void *fdt) { + clear_timer(); ticks_per_sec = stat_timer(fdt); info("ticks_per_sec: %" PRIu64 "\n", ticks_per_sec); info("current ticks: %" PRIu64 "\n", current_ticks()); @@ -151,14 +152,23 @@ id_t new_rel_timer(id_t tid, ticks_t ticks) id_t new_abs_timer(id_t tid, ticks_t ticks) { + /* if there are no active timers or this timer is before the next active + * timer, start the hardware timer */ + struct timer *t = newest_timer(); + if (!t || ticks < t->ticks) + set_timer(ticks); + id_t id = __new_timer(tid, ticks); - set_timer(ticks); return id; } struct timer *newest_timer() { - struct sp_node *t = sp_first(sp_root(__cpu_timers())); + struct sp_node *r = sp_root(__cpu_timers()); + if (!r) + return NULL; + + struct sp_node *t = sp_first(r); return &timer_container(t)->timer; } @@ -202,9 +212,25 @@ void handle_timer() /** @todo should this also disable irqs? */ bkl_lock(); struct timer *t = newest_timer(); + if (!t) { + info("spurious timer\n"); + clear_timer(); + bkl_unlock(); + return; + } + id_t tid = t->tid; remove_timer(t); + + /* maybe schedule next timer event, maybe disable timer so we don't + * start infinitely retrigger the timer interrupt */ + t = newest_timer(); + if (t) + set_timer(t->ticks); + else + clear_timer(); + struct tcb *r = get_tcb(tid); if (!r || orphan(r)) { info("tcb %llu dead at timer\n", @@ -213,6 +239,7 @@ void handle_timer() return; } + /** @todo check that timer didn't trigger before scheduled time? */ notify(r, NOTIFY_TIMER); bkl_unlock(); } |