Commit 22a9c26a authored by Peter Maydell's avatar Peter Maydell
Browse files

nvic: Don't apply group priority mask to negative priorities 



In several places we were unconditionally applying the
nvic_gprio_mask() to a priority value. This is incorrect
if the priority is one of the fixed negative priority
values (for NMI and HardFault), so don't do it.

This bug would have caused both NMI and HardFault to be
considered as the same priority and so NMI wouldn't
correctly preempt HardFault.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Message-id: 1505137930-13255-5-git-send-email-peter.maydell@linaro.org
parent c6158878

hw/intc/armv7m_nvic.c

+9 −2
Original line number Diff line number Diff line
@@ -152,8 +152,12 @@ static void nvic_recompute_state(NVICState *s) 
        }

    }



    if (active_prio > 0) {

        active_prio &= nvic_gprio_mask(s);

    }



    s->vectpending = pend_irq;

    s->exception_prio = active_prio & nvic_gprio_mask(s);

    s->exception_prio = active_prio;



    trace_nvic_recompute_state(s->vectpending, s->exception_prio);

}
@@ -329,7 +333,10 @@ void armv7m_nvic_acknowledge_irq(void *opaque) 
    assert(vec->enabled);

    assert(vec->pending);



    pendgroupprio = vec->prio & nvic_gprio_mask(s);

    pendgroupprio = vec->prio;

    if (pendgroupprio > 0) {

        pendgroupprio &= nvic_gprio_mask(s);

    }

    assert(pendgroupprio < running);



    trace_nvic_acknowledge_irq(pending, vec->prio);