voron

experimental ARM OS
git clone git://git.2f30.org/voron.git
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commit ea08b81621fd1ea148c3ef9b63817f0e73e7c65f
parent b9f1263897df850447d121dadd40182309406668
Author: oblique <psyberbits@gmail.com>
Date:   Mon Oct 29 13:42:18 +0200

improved force schedule

Diffstat:
kernel/sched.c | 46+++++++++++++++++++++++++++++++---------------
1 file changed, 31 insertions(+), 15 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c @@ -4,6 +4,7 @@ #include <dmtimer.h> #include <sched.h> #include <mmu.h> +#include <irq.h> #include <p_modes.h> struct task_struct *curr_task = NULL; @@ -31,6 +32,8 @@ task_remove(void) current->state = TASK_TERMINATE; /* force schedule */ schedule(); + while (1) + asm volatile("wfi" : : : "memory"); } int @@ -72,30 +75,29 @@ kthread_create(void (*routine)(void *), void *arg) list_add(&task->list, &task_list_head); spinlock_unlock(task->lock); + /* force schedule if it's the only task */ + if (list_is_singular(&task_list_head)) + schedule(); + return 0; } +/* force schedule */ void schedule(void) { - u32 ms = uatomic_read(&ms_counter); - /* this guarantees that will loop until scheduler will executed */ - while (ms == uatomic_read(&ms_counter)) { - /* trigger scheduler timer */ - dmtimer_trigger(1); - /* wait for interrupt */ - asm volatile("wfi"); - } + /* trigger SGI */ + irq_trigger_sgi(1); } static void __idle(void) { while (1) - asm volatile("wfi"); + asm volatile("wfi" : : : "memory"); } -static void +static inline void __switch_to(struct regs *regs, struct task_struct *new_curr) { if (!new_curr) { @@ -107,8 +109,10 @@ __switch_to(struct regs *regs, struct task_struct *new_curr) } else *regs = new_curr->regs; current = new_curr; + /* data synchronization barrier */ dsb(); - asm volatile("clrex"); + /* clear exclusive address access */ + asm volatile("clrex" : : : "memory"); } @@ -118,10 +122,6 @@ sched(struct regs *regs) struct list_head *iter, *curr_list; struct task_struct *task, *new_curr; - /* TODO: if scheduler is triggered by schedule() - * then add the correct value */ - uatomic_add(SCHED_INT_MS, &ms_counter); - if (list_empty(&task_list_head)) return; @@ -171,7 +171,11 @@ sleep(u32 seconds) { current->state = TASK_SLEEP; current->wakeup_ms = uatomic_read(&ms_counter) + seconds * 1000; + /* force schedule */ schedule(); + /* make sure that we rescheduled */ + while (current->state == TASK_SLEEP) + asm volatile("wfi" : : : "memory"); } void @@ -183,12 +187,23 @@ msleep(u32 milliseconds) if (milliseconds < SCHED_INT_MS) milliseconds = SCHED_INT_MS; current->wakeup_ms = uatomic_read(&ms_counter) + milliseconds; + /* force schedule */ schedule(); + /* make sure that we rescheduled */ + while (current->state == TASK_SLEEP) + asm volatile("wfi" : : : "memory"); } static void sched_handler(__unused int timer_id, struct regs *regs) { + uatomic_add(SCHED_INT_MS, &ms_counter); + sched(regs); +} + +static void +force_sched_handler(__unused u32 irq_num, struct regs *regs) +{ sched(regs); } @@ -197,5 +212,6 @@ void sched_init(void) { INIT_LIST_HEAD(&task_list_head); + irq_register(1, force_sched_handler); dmtimer_register(1, sched_handler, SCHED_INT_MS); }