From 3889ba70102ed8c609e42c1d3563c8c041ce0511 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 15 Mar 2021 11:56:29 +0000 Subject: arm64: irq: allow FIQs to be handled On contemporary platforms we don't use FIQ, and treat any stray FIQ as a fatal event. However, some platforms have an interrupt controller wired to FIQ, and need to handle FIQ as part of regular operation. So that we can support both cases dynamically, this patch updates the FIQ exception handling code to operate the same way as the IRQ handling code, with its own handle_arch_fiq handler. Where a root FIQ handler is not registered, an unexpected FIQ exception will trigger the default FIQ handler, which will panic() as today. Where a root FIQ handler is registered, handling of the FIQ is deferred to that handler. As el0_fiq_invalid_compat is supplanted by el0_fiq, the former is removed. For !CONFIG_COMPAT builds we never expect to take an exception from AArch32 EL0, so we keep the common el0_fiq_invalid handler. Signed-off-by: Mark Rutland Tested-by: Hector Martin Cc: James Morse Cc: Marc Zyngier Cc: Thomas Gleixner Cc: Will Deacon Acked-by: Will Deacon Link: https://lore.kernel.org/r/20210315115629.57191-7-mark.rutland@arm.com Signed-off-by: Catalin Marinas --- arch/arm64/kernel/irq.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'arch/arm64/kernel/irq.c') diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c index 2fe0b535de30..bda49430c9ea 100644 --- a/arch/arm64/kernel/irq.c +++ b/arch/arm64/kernel/irq.c @@ -76,7 +76,13 @@ static void default_handle_irq(struct pt_regs *regs) panic("IRQ taken without a root IRQ handler\n"); } +static void default_handle_fiq(struct pt_regs *regs) +{ + panic("FIQ taken without a root FIQ handler\n"); +} + void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq; +void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq; int __init set_handle_irq(void (*handle_irq)(struct pt_regs *)) { @@ -88,6 +94,16 @@ int __init set_handle_irq(void (*handle_irq)(struct pt_regs *)) return 0; } +int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *)) +{ + if (handle_arch_fiq != default_handle_fiq) + return -EBUSY; + + handle_arch_fiq = handle_fiq; + pr_info("Root FIQ handler: %ps\n", handle_fiq); + return 0; +} + void __init init_IRQ(void) { init_irq_stacks(); -- cgit