diff mbox series

[PULL,04/18] nvic: Don't apply group priority mask to negative priorities

Message ID 1505411573-27848-5-git-send-email-peter.maydell@linaro.org
State Accepted
Commit 22a9c26af62f9772b7c0512e88f97d0d1f2e0872
Headers show
Series target-arm queue | expand

Commit Message

Peter Maydell Sept. 14, 2017, 5:52 p.m. UTC 
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: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Message-id: 1505137930-13255-5-git-send-email-peter.maydell@linaro.org
---
 hw/intc/armv7m_nvic.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

-- 
2.7.4
diff mbox series

Patch

diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index 1fecfd6..d3e2056 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -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);