Thread (26 messages) 26 messages, 4 authors, 2021-02-24

Re: [PATCH 5/8] arm64: irq: add a default handle_irq panic function

From: Mark Rutland <mark.rutland@arm.com>
Date: 2021-02-22 10:05:21
Also in: lkml

On Fri, Feb 19, 2021 at 11:39:01AM +0000, Mark Rutland wrote:
If we accidentally unmask IRQs before we've registered an IRQ
controller, handle_arch_irq will be NULL, and the IRQ exception handler
will branch to a bogus address.

To make this easier to debug, this patch initialises handle_arch_irq to
a default handler which will panic(), making such problems easier to
debug. When we add support for FIQ handlers, we can follow the same
approach.
-void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
+void default_handle_irq(struct pt_regs *regs)
+{
+	panic("IRQ taken without a registered IRQ controller\n");
+}
The kbuild test robot pointed out that this should be static (likewise
with default_handle_fiq in patch 8), since it's only used within this
file, so I've updated that in my branch.

Mark.
quoted hunk ↗ jump to hunk
+
+void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
 
 int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 {
-	if (handle_arch_irq)
+	if (handle_arch_irq != default_handle_irq)
 		return -EBUSY;
 
 	handle_arch_irq = handle_irq;
@@ -87,7 +92,7 @@ void __init init_IRQ(void)
 	init_irq_stacks();
 	init_irq_scs();
 	irqchip_init();
-	if (!handle_arch_irq)
+	if (handle_arch_irq == default_handle_irq)
 		panic("No interrupt controller found.");
 
 	if (system_uses_irq_prio_masking()) {
-- 
2.11.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help