[PATCH] irqchip/gic-v3: Print a warning for out-of-range interrupt numbers

[Geert Uytterhoeven]

gic_irq_domain_translate() does not check if an interrupt number lies
within the valid range of the specified interrupt type.  Add these
checks, and print a warning if the interrupt number is out of range.

This can help flagging incorrectly described Extended SPI and PPI
interrupts in DT.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
This would have prevented the issue fixed by "[PATCH] arm64: dts:
renesas: r8a78000: Fix out-of-range SPI interrupt numbers"[1].

[1] https://lore.kernel.org/1f9dd274720ea1b66617a5dd84f76c3efc829dc8.1772641415.git.geert+renesas@xxxxxxxxx
---
 drivers/irqchip/irq-gic-v3.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 20f13b686ab22faf..d75163e71bf22473 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1603,15 +1603,27 @@ static int gic_irq_domain_translate(struct irq_domain *d,
 
 		switch (fwspec->param[0]) {
 		case 0:			/* SPI */
+			if (fwspec->param[1] > 987)
+				pr_warn_once("SPI %u out of range (use ESPI?)\n",
+					     fwspec->param[1]);
 			*hwirq = fwspec->param[1] + 32;
 			break;
 		case 1:			/* PPI */
+			if (fwspec->param[1] > 16)
+				pr_warn_once("PPI %u out of range (use EPPI?)\n",
+					     fwspec->param[1]);
 			*hwirq = fwspec->param[1] + 16;
 			break;
 		case 2:			/* ESPI */
+			if (fwspec->param[1] > 1023)
+				pr_warn_once("ESPI %u out of range\n",
+					     fwspec->param[1]);
 			*hwirq = fwspec->param[1] + ESPI_BASE_INTID;
 			break;
 		case 3:			/* EPPI */
+			if (fwspec->param[1] > 63)
+				pr_warn_once("EPPI %u out of range\n",
+					     fwspec->param[1]);
 			*hwirq = fwspec->param[1] + EPPI_BASE_INTID;
 			break;
 		case GIC_IRQ_TYPE_LPI:	/* LPI */
-- 
2.43.0