From 5255fcf8e47acd059e2f0d414841c40231c1bd22 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 12 Sep 2017 19:13:51 +0100 Subject: [PATCH] nvic: Add cached vectpending_prio state Instead of looking up the pending priority in nvic_pending_prio(), cache it in a new state struct field. The calculation of the pending priority given the interrupt number is more complicated in v8M with the security extension, so the caching will be worthwhile. This changes nvic_pending_prio() from returning a full (group + subpriority) priority value to returning a group priority. This doesn't require changes to its callsites because we use it only in comparisons of the form execution_prio > nvic_pending_prio() and execution priority is always a group priority, so a test (exec prio > full prio) is true if and only if (execprio > group_prio). (Architecturally the expected comparison is with the group priority for this sort of "would we preempt" test; we were only doing a test with a full priority as an optimisation to avoid the mask, which is possible precisely because the two comparisons always give the same answer.) Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 1505240046-11454-5-git-send-email-peter.maydell@linaro.org --- hw/intc/armv7m_nvic.c | 23 +++++++++++++---------- hw/intc/trace-events | 2 +- include/hw/intc/armv7m_nvic.h | 2 ++ 3 files changed, 16 insertions(+), 11 deletions(-) diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c index a11df3d155..fa5dd23f09 100644 --- a/hw/intc/armv7m_nvic.c +++ b/hw/intc/armv7m_nvic.c @@ -61,10 +61,10 @@ static const uint8_t nvic_id[] = { static int nvic_pending_prio(NVICState *s) { - /* return the priority of the current pending interrupt, + /* return the group priority of the current pending interrupt, * or NVIC_NOEXC_PRIO if no interrupt is pending */ - return s->vectpending ? s->vectors[s->vectpending].prio : NVIC_NOEXC_PRIO; + return s->vectpending_prio; } /* Return the value of the ISCR RETTOBASE bit: @@ -156,10 +156,17 @@ static void nvic_recompute_state(NVICState *s) active_prio &= nvic_gprio_mask(s); } + if (pend_prio > 0) { + pend_prio &= nvic_gprio_mask(s); + } + s->vectpending = pend_irq; + s->vectpending_prio = pend_prio; s->exception_prio = active_prio; - trace_nvic_recompute_state(s->vectpending, s->exception_prio); + trace_nvic_recompute_state(s->vectpending, + s->vectpending_prio, + s->exception_prio); } /* Return the current execution priority of the CPU @@ -323,7 +330,6 @@ void armv7m_nvic_acknowledge_irq(void *opaque) CPUARMState *env = &s->cpu->env; const int pending = s->vectpending; const int running = nvic_exec_prio(s); - int pendgroupprio; VecInfo *vec; assert(pending > ARMV7M_EXCP_RESET && pending < s->num_irq); @@ -333,13 +339,9 @@ void armv7m_nvic_acknowledge_irq(void *opaque) assert(vec->enabled); assert(vec->pending); - pendgroupprio = vec->prio; - if (pendgroupprio > 0) { - pendgroupprio &= nvic_gprio_mask(s); - } - assert(pendgroupprio < running); + assert(s->vectpending_prio < running); - trace_nvic_acknowledge_irq(pending, vec->prio); + trace_nvic_acknowledge_irq(pending, s->vectpending_prio); vec->active = 1; vec->pending = 0; @@ -1255,6 +1257,7 @@ static void armv7m_nvic_reset(DeviceState *dev) s->exception_prio = NVIC_NOEXC_PRIO; s->vectpending = 0; s->vectpending_is_s_banked = false; + s->vectpending_prio = NVIC_NOEXC_PRIO; } static void nvic_systick_trigger(void *opaque, int n, int level) diff --git a/hw/intc/trace-events b/hw/intc/trace-events index 4762329482..5635a5fbbf 100644 --- a/hw/intc/trace-events +++ b/hw/intc/trace-events @@ -167,7 +167,7 @@ gicv3_redist_set_irq(uint32_t cpu, int irq, int level) "GICv3 redistributor 0x%x gicv3_redist_send_sgi(uint32_t cpu, int irq) "GICv3 redistributor 0x%x pending SGI %d" # hw/intc/armv7m_nvic.c -nvic_recompute_state(int vectpending, int exception_prio) "NVIC state recomputed: vectpending %d exception_prio %d" +nvic_recompute_state(int vectpending, int vectpending_prio, int exception_prio) "NVIC state recomputed: vectpending %d vectpending_prio %d exception_prio %d" nvic_set_prio(int irq, uint8_t prio) "NVIC set irq %d priority %d" nvic_irq_update(int vectpending, int pendprio, int exception_prio, int level) "NVIC vectpending %d pending prio %d exception_prio %d: setting irq line to %d" nvic_escalate_prio(int irq, int irqprio, int runprio) "NVIC escalating irq %d to HardFault: insufficient priority %d >= %d" diff --git a/include/hw/intc/armv7m_nvic.h b/include/hw/intc/armv7m_nvic.h index 87c78b3c26..329774e82b 100644 --- a/include/hw/intc/armv7m_nvic.h +++ b/include/hw/intc/armv7m_nvic.h @@ -62,6 +62,7 @@ typedef struct NVICState { * - vectpending * - vectpending_is_secure * - exception_prio + * - vectpending_prio */ unsigned int vectpending; /* highest prio pending enabled exception */ /* true if vectpending is a banked secure exception, ie it is in @@ -69,6 +70,7 @@ typedef struct NVICState { */ bool vectpending_is_s_banked; int exception_prio; /* group prio of the highest prio active exception */ + int vectpending_prio; /* group prio of the exeception in vectpending */ MemoryRegion sysregmem; MemoryRegion sysreg_ns_mem; -- GitLab