hw/intc/arm_gic: Change behavior of EOIR writes

Grouping (GICv2) and Security Extensions change the behavior of EOIR
writes. Completing Group0 interrupts is only allowed from Secure state.

Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch>
Signed-off-by: Greg Bellows <greg.bellows@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1430502643-25909-13-git-send-email-peter.maydell@linaro.org
Message-id: 1429113742-8371-13-git-send-email-greg.bellows@linaro.org
[PMM: Rather than go to great lengths to ignore the UNPREDICTABLE case
 of a Secure EOI of a Group1 (NS) irq with AckCtl == 0, we just let
 it fall through; add a comment about it.]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/intc/arm_gic.c

@@ -382,7 +382,7 @@ static uint8_t gic_get_running_priority(GICState *s, int cpu, MemTxAttrs attrs)
     }
 }
 
-void gic_complete_irq(GICState *s, int cpu, int irq)
+void gic_complete_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs)
 {
     int update = 0;
     int cm = 1 << cpu;
@@ -412,6 +412,16 @@ void gic_complete_irq(GICState *s, int cpu, int irq)
         }
     }
 
+    if (s->security_extn && !attrs.secure && !GIC_TEST_GROUP(irq, cm)) {
+        DPRINTF("Non-secure EOI for Group0 interrupt %d ignored\n", irq);
+        return;
+    }
+
+    /* Secure EOI with GICC_CTLR.AckCtl == 0 when the IRQ is a Group 1
+     * interrupt is UNPREDICTABLE. We choose to handle it as if AckCtl == 1,
+     * i.e. go ahead and complete the irq anyway.
+     */
+
     if (irq != s->running_irq[cpu]) {
         /* Complete an IRQ that is not currently running.  */
         int tmp = s->running_irq[cpu];
@@ -959,7 +969,7 @@ static MemTxResult gic_cpu_write(GICState *s, int cpu, int offset,
         }
         break;
     case 0x10: /* End Of Interrupt */
-        gic_complete_irq(s, cpu, value & 0x3ff);
+        gic_complete_irq(s, cpu, value & 0x3ff, attrs);
         return MEMTX_OK;
     case 0x1c: /* Aliased Binary Point */
         if (!gic_has_groups(s) || (s->security_extn && !attrs.secure)) {

hw/intc/armv7m_nvic.c

@@ -144,7 +144,7 @@ void armv7m_nvic_complete_irq(void *opaque, int irq)
     nvic_state *s = (nvic_state *)opaque;
     if (irq >= 16)
         irq += 16;
-    gic_complete_irq(&s->gic, 0, irq);
+    gic_complete_irq(&s->gic, 0, irq, MEMTXATTRS_UNSPECIFIED);
 }
 
 static uint32_t nvic_readl(nvic_state *s, uint32_t offset)

hw/intc/gic_internal.h

@@ -79,7 +79,7 @@
 
 void gic_set_pending_private(GICState *s, int cpu, int irq);
 uint32_t gic_acknowledge_irq(GICState *s, int cpu);
-void gic_complete_irq(GICState *s, int cpu, int irq);
+void gic_complete_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs);
 void gic_update(GICState *s);
 void gic_init_irqs_and_distributor(GICState *s);
 void gic_set_priority(GICState *s, int cpu, int irq, uint8_t val,