[irqchip: irq/irqchip-next] irqchip/gic, gic-v3: Make SGIs use handle_percpu_devid_irq()

From: irqchip-bot for Valentin Schneider
Date: Fri Dec 11 2020 - 10:01:50 EST


The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID: 6abbd6988971aaa607b026eaa0ffd2301352f2ea
Gitweb: https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/6abbd6988971aaa607b026eaa0ffd2301352f2ea
Author: Valentin Schneider <valentin.schneider@xxxxxxx>
AuthorDate: Mon, 09 Nov 2020 09:41:17
Committer: Marc Zyngier <maz@xxxxxxxxxx>
CommitterDate: Fri, 11 Dec 2020 14:47:49

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@xxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20201109094121.29975-2-valentin.schneider@xxxxxxx
---
drivers/irqchip/irq-gic-v3.c | 6 ------
drivers/irqchip/irq-gic.c | 8 +-------
2 files changed, 1 insertion(+), 13 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 16fecc0..3fc6537 100644
--- 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
--- 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);