[patch 21/28] PNPACPI: ignore _PRS interrupt numbers larger than PNP_IRQ_NR

[Bjorn Helgaas]

ACPI Extended Interrupt Descriptors can encode 32-bit interrupt
numbers, so an interrupt number may exceed the size of the bitmap
we use to track possible IRQ settings.

To avoid corrupting memory, complain and ignore too-large interrupt
numbers.

There's similar code in pnpacpi_parse_irq_option(), but I didn't
change that because the small IRQ descriptor can only encode
IRQs 0-15, which do not exceed bitmap size.

In the future, we could handle IRQ numbers greater than PNP_IRQ_NR
by replacing the bitmap with a table or list.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@xxxxxx>
Acked-by: Rene Herman <rene.herman@xxxxxxxxx>

Index: work14/drivers/pnp/pnpacpi/rsparser.c
===================================================================
--- work14.orig/drivers/pnp/pnpacpi/rsparser.c	2008-06-17 15:52:27.000000000 -0600
+++ work14/drivers/pnp/pnpacpi/rsparser.c	2008-06-17 15:52:29.000000000 -0600
@@ -435,9 +435,16 @@ static __init void pnpacpi_parse_irq_opt
 		return;
 
 	bitmap_zero(map.bits, PNP_IRQ_NR);
-	for (i = 0; i < p->interrupt_count; i++)
-		if (p->interrupts[i])
-			__set_bit(p->interrupts[i], map.bits);
+	for (i = 0; i < p->interrupt_count; i++) {
+		if (p->interrupts[i]) {
+			if (p->interrupts[i] < PNP_IRQ_NR)
+				__set_bit(p->interrupts[i], map.bits);
+			else
+				dev_err(&dev->dev, "ignoring IRQ %d option "
+					"(too large for %d entry bitmap)\n",
+					p->interrupts[i], PNP_IRQ_NR);
+		}
+	}
 
 	flags = irq_flags(p->triggering, p->polarity, p->sharable);
 	pnp_register_irq_resource(dev, option, &map, flags);

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