arm64: irq: allow FIQs to be handled
authorMark Rutland <mark.rutland@arm.com>
Mon, 15 Mar 2021 11:56:29 +0000 (11:56 +0000)
committerCatalin Marinas <catalin.marinas@arm.com>
Wed, 24 Mar 2021 20:19:30 +0000 (20:19 +0000)
commit3889ba70102ed8c609e42c1d3563c8c041ce0511
treeba2dfc38f405ce6e63aa6095e6675334b457dae7
parentf0098155d337cab638cf18e37a3e9257d653d481
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 <mark.rutland@arm.com>
Tested-by: 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>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210315115629.57191-7-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/include/asm/irq.h
arch/arm64/kernel/entry.S
arch/arm64/kernel/irq.c