irqchip/gic, gic-v3: Make SGIs use handle_percpu_devid_irq()

handle_percpu_devid_fasteoi_ipi() states:

 * The biggest difference with the IRQ version is that the interrupt is
 * EOIed early, as the IPI could result in a context switch, and we need to
 * make sure the IPI can fire again

All that can actually happen scheduler-wise within the handling of an IPI
is the raising of TIF_NEED_RESCHED (and / or folding thereof into
preempt_count); see scheduler_ipi() or sched_ttwu_pending() for instance.

Said flag / preempt_count is evaluated some time later before returning to
whatever context was interrupted, and this gates a call to
preempt_schedule_irq() (arm64_preempt_schedule_irq() in arm64).

Per the above, SGI's do not need a different handler than PPI's, so make
them use the same (handle_percpu_devid_irq).

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201109094121.29975-2-valentin.schneider@arm.com

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 16fecc0..3fc6537 100644 (file)
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1302,12 +1302,6 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
 
        switch (__get_intid_range(hw)) {
        case SGI_RANGE:
-               irq_set_percpu_devid(irq);
-               irq_domain_set_info(d, irq, hw, chip, d->host_data,
-                                   handle_percpu_devid_fasteoi_ipi,
-                                   NULL, NULL);
-               break;
-
        case PPI_RANGE:
        case EPPI_RANGE:
                irq_set_percpu_devid(irq);

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index a3c2f18..b1d9c22 100644 (file)
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -1005,13 +1005,7 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
        struct irq_data *irqd = irq_desc_get_irq_data(irq_to_desc(irq));
 
        switch (hw) {
-       case 0 ... 15:
-               irq_set_percpu_devid(irq);
-               irq_domain_set_info(d, irq, hw, &gic->chip, d->host_data,
-                                   handle_percpu_devid_fasteoi_ipi,
-                                   NULL, NULL);
-               break;
-       case 16 ... 31:
+       case 0 ... 31:
                irq_set_percpu_devid(irq);
                irq_domain_set_info(d, irq, hw, &gic->chip, d->host_data,
                                    handle_percpu_devid_irq, NULL, NULL);