Re: [PATCH 02/15] irq: mips: stop (ab)using handle_domain_irq()

On Thu, Oct 21, 2021 at 07:02:23PM +0100, Mark Rutland wrote:

On MIPS, the only user of handle_domain_irq() is octeon_irq_ciu3_ip2(),
which is called from the platform-specific plat_irq_dispatch() function
invoked from the early assembly code.

No other irqchip relevant to arch/mips uses handle_domain_irq():

* No other plat_irq_dispatch() function transitively calls
  handle_domain_irq().

* No other vectored IRQ dispatch function registered with
  set_vi_handler() calls handle_domain_irq().

* No chained irqchip handlers call handle_domain_irq(), which makes
  sense as this is meant to only be used by root irqchip handlers.

Currently octeon_irq_ciu3_ip2() passes NULL as the `regs` argument to
handle_domain_irq(), and as handle_domain_irq() will pass this to
set_irq_regs(), any invoked IRQ handlers will erroneously see a NULL
pt_regs if they call get_pt_regs().

Fix this by calling generic_handle_domain_irq() directly, and performing
the necessary irq_{enter,exit}() logic directly in
octeon_irq_ciu3_ip2(). At the same time, deselect HANDLE_DOMAIN_IRQ,
which subsequent patches will remove.

Other than the corrected behaviour of get_pt_regs(), there should be no
functional change as a result of this patch.

Fixes: ce210d35bb93c2c5 ("MIPS: OCTEON: Add support for OCTEON III interrupt controller.")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <redacted>
---
 arch/mips/Kconfig                    | 1 -
 arch/mips/cavium-octeon/octeon-irq.c | 5 ++++-
 2 files changed, 4 insertions(+), 2 deletions(-)

Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

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