Messages in this thread Patch in this message | | | From | Mark Rutland <> | Subject | [PATCHv2 5/8] arm64: irq: rework root IRQ handler registration | Date | Tue, 2 Mar 2021 10:12:08 +0000 |
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If we accidentally unmask IRQs before we've registered a root IRQ handler, 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.
When we add support for a root FIQ handler, it's possible to have root IRQ handler without an root FIQ handler, and in theory the inverse is also possible. To permit this, and to keep the IRQ/FIQ registration logic similar, this patch removes the panic in the absence of a root IRQ controller. Instead, set_handle_irq() logs when a handler is registered, which is sufficient for debug purposes.
Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Hector Martin <marcan@marcan.st> Cc: James Morse <james.morse@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> --- arch/arm64/kernel/irq.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c index ad63bd50fa7b..2fe0b535de30 100644 --- a/arch/arm64/kernel/irq.c +++ b/arch/arm64/kernel/irq.c @@ -71,14 +71,20 @@ static void init_irq_stacks(void) } #endif -void (*handle_arch_irq)(struct pt_regs *) __ro_after_init; +static void default_handle_irq(struct pt_regs *regs) +{ + panic("IRQ taken without a root IRQ handler\n"); +} + +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; + pr_info("Root IRQ handler: %ps\n", handle_irq); return 0; } @@ -87,8 +93,6 @@ void __init init_IRQ(void) init_irq_stacks(); init_irq_scs(); irqchip_init(); - if (!handle_arch_irq) - panic("No interrupt controller found."); if (system_uses_irq_prio_masking()) { /* -- 2.11.0
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