static void sys_unmap_wrap(struct x86_exregs *regs)
{
L4_Word_t control = regs->eax;
/* TODO: pass utcb to sys_unmap()? */
void *utcb = thread_get_utcb(get_current_thread());
if((control & 0x3f) > 0) L4_VREG(utcb, L4_TCR_MR(0)) = regs->esi;
sys_unmap(control);
regs->esi = L4_VREG(utcb, L4_TCR_MR(0));
}
/* call latent interrupt handlers, resolve preemptions, return the winner.
* caller must check for retval == current && I ∈ current.PreemptFlags, and
* engage max_delay as appropriate.
*/
struct thread *irq_call_deferred(struct thread *next)
{
assert(!x86_irq_is_enabled());
assert(!kernel_irq_ok);
/* initialize resolution state, feed it a primary event. */
struct thread *current = get_current_thread();
void *cur_utcb = current != NULL ? thread_get_utcb(current) : NULL;
next = sched_resolve_next(current, cur_utcb, current, next);
int n_defer_masks = (max_irq_handler + WORD_BITS) / WORD_BITS, n_done;
do {
if(!irq_defer_active) break;
n_done = 0;
for(int i=0; i < n_defer_masks; i++) {
L4_Word_t m = defer_set_masks[i];
while(m != 0) {
int b = ffsl(m) - 1;
assert(b >= 0);
m &= ~(1ul << b);
int vecn = i * WORD_BITS + b;
int n_defers = deferred_vecs[vecn];
assert(n_defers > 0);
irq_handler_fn handler = choose_handler(vecn);
deferred_vecs[vecn] = 0;
defer_set_masks[i] &= ~(1ul << b);
x86_irq_enable();
next = sched_resolve_next(current, cur_utcb, next,
(*handler)(n_defers > 1 ? -vecn : vecn));
x86_irq_disable();
n_done++;
}
}
} while(n_done > 0);
irq_defer_active = false;
return next;
}
/* the IAPC PIT 1000hz interrupt. */
void isr_irq0_bottom(struct x86_exregs *regs)
{
uint64_t now = ++global_timer_count;
(*systemclock_p) += 1000;
(*global_pic.send_eoi)(0);
if(now < preempt_timer_count) return;
TRACE("%s: preempt hit at now=%u\n", __func__, (unsigned)now);
preempt_timer_count = ~0ull;
assert(preempt_thread == NULL
|| thread_is_valid(preempt_thread));
if(irq_in_kernel(regs) && !kernel_irq_ok) {
/* defer a magical call to on_preempt() as though it were any old
* interrupt.
*/
irq_defer(0x20);
TRACE("%s: preempt deferred\n", __func__);
return;
}
struct thread *current = get_current_thread();
bool ctx_saved = false;
if(CHECK_FLAG(preempt_status, PS_DELAYED)
|| (current != NULL && preempt_thread != NULL
&& preempt_thread->pri <= current->sens_pri
&& current->max_delay == 0
&& CHECK_FLAG_ALL(L4_VREG(thread_get_utcb(current),
L4_TCR_COP_PREEMPT), 0x60)))
{
assert(!CHECK_FLAG(current->flags, TF_SYSCALL));
save_user_ex(regs);
ctx_saved = true;
}
struct thread *next = on_preempt(0x20);
if(current == NULL) {
/* scheduled activation from idle. */
if(next != NULL) {
TRACE("%s: scheduled activation of next=%lu:%lu\n", __func__,
TID_THREADNUM(next->id), TID_VERSION(next->id));
} else {
TRACE("%s: idle -> idle\n", __func__);
}
kernel_irq_ok = false;
} else if(next != current) {
/* async preëmption of @current. */
assert(!CHECK_FLAG(current->flags, TF_SYSCALL));
TRACE("%s: async preëmpt of %lu:%lu\n", __func__,
TID_THREADNUM(current->id), TID_VERSION(current->id));
if(!ctx_saved) save_user_ex(regs);
if(!IS_IPC(current->status)) {
current->status = TS_READY;
current->wakeup_time = 0;
sq_update_thread(current);
}
}
return_from_irq(next);
TRACE("%s: returning to userspace (preempt_timer_count'=%u)\n",
__func__, (unsigned)preempt_timer_count);
BUG_ON(next != current, "shouldn't get here!");
}