powerpc/kdump: Use chip->shutdown to disable IRQs

powerpc/kdump: Use chip->shutdown to disable IRQs

Commit: 5d7a87217de48b234b3c8ff8a73059947d822e07 upstream

I saw this in a kdump kernel:

IOMMU table initialized, virtual merging enabled Interrupt 155954 (real) is invalid, disabling it. Interrupt 155953 (real) is invalid, disabling it.

ie we took some spurious interrupts. default_machine_crash_shutdown tries to disable all interrupt sources but uses chip->disable which maps to the default action of:

static void default_disable(unsigned int irq)
{
}

If we use chip->shutdown, then we actually mask the IRQ:

static void default_shutdown(unsigned int irq) {
struct irq_desc *desc = irq_to_desc(irq);

desc->chip->mask(irq);
desc->status |= IRQ_MASKED;
}

Not sure why we don't implement a ->disable action for xics.c, or why default_disable doesn't mask the interrupt.

---
 arch/powerpc/kernel/crash.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: b/arch/powerpc/kernel/crash.c
===================================================================
@@ -382,7 +382,7 @@

			desc->chip->eoi(i);

		if (!(desc->status & IRQ_DISABLED))
-			desc->chip->disable(i);
+			desc->chip->shutdown(i);
	}

	/*