void __ipipe_post_work_root(struct ipipe_work_header *work)
{
unsigned long flags;
void *tail;
int cpu;
/*
* Subtle: we want to use the head stall/unstall operators,
* not the hard_* routines to protect against races. This way,
* we ensure that a root-based caller will trigger the virq
* handling immediately when unstalling the head stage, as a
* result of calling __ipipe_sync_pipeline() under the hood.
*/
flags = ipipe_test_and_stall_head();
cpu = ipipe_processor_id();
tail = per_cpu(work_tail, cpu);
if (WARN_ON_ONCE((unsigned char *)tail + work->size >=
per_cpu(work_buf, cpu) + WORKBUF_SIZE))
goto out;
/* Work handling is deferred, so data has to be copied. */
memcpy(tail, work, work->size);
per_cpu(work_tail, cpu) = tail + work->size;
ipipe_post_irq_root(__ipipe_work_virq);
out:
ipipe_restore_head(flags);
}
/* Always called with hw interrupts off. */
void __ipipe_do_critical_sync(unsigned int irq, void *cookie)
{
int cpu = ipipe_processor_id();
cpu_set(cpu, __ipipe_cpu_sync_map);
/*
* Now we are in sync with the lock requestor running on
* another CPU. Enter a spinning wait until he releases the
* global lock.
*/
spin_lock(&__ipipe_cpu_barrier);
/* Got it. Now get out. */
/* Call the sync routine if any. */
if (__ipipe_cpu_sync)
__ipipe_cpu_sync();
cpu_set(cpu, __ipipe_cpu_pass_map);
spin_unlock(&__ipipe_cpu_barrier);
cpu_clear(cpu, __ipipe_cpu_sync_map);
}
int __ipipe_send_ipi(unsigned ipi, cpumask_t cpumask)
{
unsigned long flags;
int self;
local_irq_save_hw(flags);
self = cpu_isset(ipipe_processor_id(),cpumask);
cpu_clear(ipipe_processor_id(), cpumask);
if (!cpus_empty(cpumask))
apic->send_IPI_mask(&cpumask, ipipe_apic_irq_vector(ipi));
if (self)
ipipe_trigger_irq(ipi);
local_irq_restore_hw(flags);
return 0;
}
void twd_hrtimer_debug(unsigned int irq) /* hw interrupt off */
{
int cpu = ipipe_processor_id();
if ((++per_cpu(irqs, cpu) % HZ) == 0) {
#if 0
__ipipe_serial_debug("%c", 'A' + cpu);
#else
do { } while (0);
#endif
}
}
void __xntimer_init(struct xntimer *timer,
struct xnclock *clock,
void (*handler)(struct xntimer *timer),
struct xnsched *sched,
int flags)
{
spl_t s __maybe_unused;
int cpu;
#ifdef CONFIG_XENO_OPT_EXTCLOCK
timer->clock = clock;
#endif
xntimerh_init(&timer->aplink);
xntimerh_date(&timer->aplink) = XN_INFINITE;
xntimer_set_priority(timer, XNTIMER_STDPRIO);
timer->status = (XNTIMER_DEQUEUED|(flags & XNTIMER_INIT_MASK));
timer->handler = handler;
timer->interval_ns = 0;
/*
* Timers are affine to a scheduler slot, which is in turn
* bound to a real-time CPU. If no scheduler affinity was
* given, assign the timer to the scheduler slot of the
* current CPU if real-time, otherwise default to the
* scheduler slot of the first real-time CPU.
*/
if (sched)
timer->sched = sched;
else {
cpu = ipipe_processor_id();
if (!xnsched_supported_cpu(cpu))
cpu = first_cpu(xnsched_realtime_cpus);
timer->sched = xnsched_struct(cpu);
}
#ifdef CONFIG_XENO_OPT_STATS
#ifdef CONFIG_XENO_OPT_EXTCLOCK
timer->tracker = clock;
#endif
ksformat(timer->name, XNOBJECT_NAME_LEN, "%d/%s",
current->pid, current->comm);
xntimer_reset_stats(timer);
xnlock_get_irqsave(&nklock, s);
list_add_tail(&timer->next_stat, &clock->timerq);
clock->nrtimers++;
xnvfile_touch(&clock->timer_vfile);
xnlock_put_irqrestore(&nklock, s);
#endif /* CONFIG_XENO_OPT_STATS */
}
void ipipe_critical_exit(unsigned long flags)
{
if (num_online_cpus() == 1) {
hard_local_irq_restore(flags);
return;
}
#ifdef CONFIG_SMP
if (atomic_dec_and_test(&__ipipe_critical_count)) {
spin_unlock(&__ipipe_cpu_barrier);
while (!cpus_empty(__ipipe_cpu_sync_map))
cpu_relax();
cpu_clear(ipipe_processor_id(), __ipipe_cpu_lock_map);
clear_bit(0, &__ipipe_critical_lock);
smp_mb__after_clear_bit();
}
#endif /* CONFIG_SMP */
hard_local_irq_restore(flags);
}
unsigned long ipipe_critical_enter(void (*syncfn)(void))
{
int cpu __maybe_unused, n __maybe_unused;
unsigned long flags, loops __maybe_unused;
cpumask_t allbutself __maybe_unused;
flags = hard_local_irq_save();
if (num_online_cpus() == 1)
return flags;
#ifdef CONFIG_SMP
cpu = ipipe_processor_id();
if (!cpu_test_and_set(cpu, __ipipe_cpu_lock_map)) {
while (test_and_set_bit(0, &__ipipe_critical_lock)) {
n = 0;
hard_local_irq_enable();
do
cpu_relax();
while (++n < cpu);
hard_local_irq_disable();
}
restart:
spin_lock(&__ipipe_cpu_barrier);
__ipipe_cpu_sync = syncfn;
cpus_clear(__ipipe_cpu_pass_map);
cpu_set(cpu, __ipipe_cpu_pass_map);
/*
* Send the sync IPI to all processors but the current
* one.
*/
cpus_andnot(allbutself, cpu_online_map, __ipipe_cpu_pass_map);
ipipe_send_ipi(IPIPE_CRITICAL_IPI, allbutself);
loops = IPIPE_CRITICAL_TIMEOUT;
while (!cpus_equal(__ipipe_cpu_sync_map, allbutself)) {
if (--loops > 0) {
cpu_relax();
continue;
}
/*
* We ran into a deadlock due to a contended
* rwlock. Cancel this round and retry.
*/
__ipipe_cpu_sync = NULL;
spin_unlock(&__ipipe_cpu_barrier);
/*
* Ensure all CPUs consumed the IPI to avoid
* running __ipipe_cpu_sync prematurely. This
* usually resolves the deadlock reason too.
*/
while (!cpus_equal(cpu_online_map, __ipipe_cpu_pass_map))
cpu_relax();
goto restart;
}
}
atomic_inc(&__ipipe_critical_count);
#endif /* CONFIG_SMP */
return flags;
}
