[tip: irq/msi] genirq/irqdomain: Don't call ops->select for DOMAIN_BUS_ANY tokens

[tip-bot2 for Marc Zyngier]

The following commit has been merged into the irq/msi branch of tip:

Commit-ID:     5aa3c0cf5bba6437c9e63a56f684f61de8b503d6
Gitweb:        https://git.kernel.org/tip/5aa3c0cf5bba6437c9e63a56f684f61de8b503d6
Author:        Marc Zyngier <maz@xxxxxxxxxx>
AuthorDate:    Tue, 20 Feb 2024 11:47:31 
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 20 Feb 2024 17:30:57 +01:00

genirq/irqdomain: Don't call ops->select for DOMAIN_BUS_ANY tokens

Users of the IRQCHIP_PLATFORM_DRIVER_{BEGIN,END} helpers rely on a fwspec
containing only the fwnode (and crucially a number of parameters set to 0)
together with a DOMAIN_BUS_ANY token to check whether a parent irqchip has
probed and registered a domain.

Since de1ff306dcf4 ("genirq/irqdomain: Remove the param count restriction
from select()"), ops->select() is called unconditionally, meaning that
irqchips implementing select() now need to handle ANY as a match.

Instead of adding more esoteric checks to the individual drivers, add that
condition to irq_find_matching_fwspec(), and let it handle the corner case,
as per the comment in the function.

This restores the functionality of the above helpers.

Fixes: de1ff306dcf4 ("genirq/irqdomain: Remove the param count restriction from select()")
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Reported-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Tested-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240220114731.1898534-1-maz@xxxxxxxxxx
Link: https://lore.kernel.org/r/20240219-gic-fix-child-domain-v1-1-09f8fd2d9a8f@xxxxxxxxxx
---
 kernel/irq/irqdomain.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index aeb4165..3dd1c87 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -449,7 +449,7 @@ struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec,
 	 */
 	mutex_lock(&irq_domain_mutex);
 	list_for_each_entry(h, &irq_domain_list, link) {
-		if (h->ops->select)
+		if (h->ops->select && bus_token != DOMAIN_BUS_ANY)
 			rc = h->ops->select(h, fwspec, bus_token);
 		else if (h->ops->match)
 			rc = h->ops->match(h, to_of_node(fwnode), bus_token);