static struct irq_chip lapic_controller;
static struct irq_matrix *vector_matrix;
#ifdef CONFIG_SMP
-static DEFINE_PER_CPU(struct hlist_head, cleanup_list);
+
+static void vector_cleanup_callback(struct timer_list *tmr);
+
+struct vector_cleanup {
+ struct hlist_head head;
+ struct timer_list timer;
+};
+
+static DEFINE_PER_CPU(struct vector_cleanup, vector_cleanup) = {
+ .head = HLIST_HEAD_INIT,
+ .timer = __TIMER_INITIALIZER(vector_cleanup_callback, TIMER_PINNED),
+};
#endif
void lock_vector_lock(void)
this_cpu_write(vector_irq[vector], __setup_vector_irq(vector));
}
+static void __vector_cleanup(struct vector_cleanup *cl, bool check_irr);
+
void lapic_offline(void)
{
+ struct vector_cleanup *cl = this_cpu_ptr(&vector_cleanup);
+
lock_vector_lock();
+
+ /* In case the vector cleanup timer has not expired */
+ __vector_cleanup(cl, false);
+
irq_matrix_offline(vector_matrix);
+ WARN_ON_ONCE(try_to_del_timer_sync(&cl->timer) < 0);
+ WARN_ON_ONCE(!hlist_empty(&cl->head));
+
unlock_vector_lock();
}
apicd->move_in_progress = 0;
}
-DEFINE_IDTENTRY_SYSVEC(sysvec_irq_move_cleanup)
+static void __vector_cleanup(struct vector_cleanup *cl, bool check_irr)
{
- struct hlist_head *clhead = this_cpu_ptr(&cleanup_list);
struct apic_chip_data *apicd;
struct hlist_node *tmp;
+ bool rearm = false;
- ack_APIC_irq();
- /* Prevent vectors vanishing under us */
- raw_spin_lock(&vector_lock);
+ lockdep_assert_held(&vector_lock);
- hlist_for_each_entry_safe(apicd, tmp, clhead, clist) {
+ hlist_for_each_entry_safe(apicd, tmp, &cl->head, clist) {
unsigned int irr, vector = apicd->prev_vector;
/*
* Paranoia: Check if the vector that needs to be cleaned
- * up is registered at the APICs IRR. If so, then this is
- * not the best time to clean it up. Clean it up in the
- * next attempt by sending another IRQ_MOVE_CLEANUP_VECTOR
- * to this CPU. IRQ_MOVE_CLEANUP_VECTOR is the lowest
- * priority external vector, so on return from this
- * interrupt the device interrupt will happen first.
+ * up is registered at the APICs IRR. That's clearly a
+ * hardware issue if the vector arrived on the old target
+ * _after_ interrupts were disabled above. Keep @apicd
+ * on the list and schedule the timer again to give the CPU
+ * a chance to handle the pending interrupt.
+ *
+ * Do not check IRR when called from lapic_offline(), because
+ * fixup_irqs() was just called to scan IRR for set bits and
+ * forward them to new destination CPUs via IPIs.
*/
- irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
+ irr = check_irr ? apic_read(APIC_IRR + (vector / 32 * 0x10)) : 0;
if (irr & (1U << (vector % 32))) {
- apic->send_IPI_self(IRQ_MOVE_CLEANUP_VECTOR);
+ pr_warn_once("Moved interrupt pending in old target APIC %u\n", apicd->irq);
+ rearm = true;
continue;
}
free_moved_vector(apicd);
}
- raw_spin_unlock(&vector_lock);
+ /*
+ * Must happen under vector_lock to make the timer_pending() check
+ * in __vector_schedule_cleanup() race free against the rearm here.
+ */
+ if (rearm)
+ mod_timer(&cl->timer, jiffies + 1);
+}
+
+static void vector_cleanup_callback(struct timer_list *tmr)
+{
+ struct vector_cleanup *cl = container_of(tmr, typeof(*cl), timer);
+
+ /* Prevent vectors vanishing under us */
+ raw_spin_lock_irq(&vector_lock);
+ __vector_cleanup(cl, true);
+ raw_spin_unlock_irq(&vector_lock);
}
static void __vector_schedule_cleanup(struct apic_chip_data *apicd)
{
- unsigned int cpu;
+ unsigned int cpu = apicd->prev_cpu;
raw_spin_lock(&vector_lock);
apicd->move_in_progress = 0;
- cpu = apicd->prev_cpu;
if (cpu_online(cpu)) {
- hlist_add_head(&apicd->clist, per_cpu_ptr(&cleanup_list, cpu));
- apic->send_IPI(cpu, IRQ_MOVE_CLEANUP_VECTOR);
+ struct vector_cleanup *cl = per_cpu_ptr(&vector_cleanup, cpu);
+
+ hlist_add_head(&apicd->clist, &cl->head);
+
+ /*
+ * The lockless timer_pending() check is safe here. If it
+ * returns true, then the callback will observe this new
+ * apic data in the hlist as everything is serialized by
+ * vector lock.
+ *
+ * If it returns false then the timer is either not armed
+ * or the other CPU executes the callback, which again
+ * would be blocked on vector lock. Rearming it in the
+ * latter case makes it fire for nothing.
+ *
+ * This is also safe against the callback rearming the timer
+ * because that's serialized via vector lock too.
+ */
+ if (!timer_pending(&cl->timer)) {
+ cl->timer.expires = jiffies + 1;
+ add_timer_on(&cl->timer, cpu);
+ }
} else {
apicd->prev_vector = 0;
}
projects / linux.git / commitdiff