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-rw-r--r--target/arm/helper.c29
1 files changed, 27 insertions, 2 deletions
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 71dead7241..7f341d753c 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -2460,6 +2460,32 @@ static uint64_t gt_phys_cnt_offset(CPUARMState *env)
     return gt_phys_raw_cnt_offset(env);
 }
 
+static uint64_t gt_indirect_access_timer_offset(CPUARMState *env, int timeridx)
+{
+    /*
+     * Return the timer offset to use for indirect accesses to the timer.
+     * This is the Offset value as defined in D12.2.4.1 "Operation of the
+     * CompareValue views of the timers".
+     *
+     * The condition here is not always the same as the condition for
+     * whether to apply an offset register when doing a direct read of
+     * the counter sysreg; those conditions are described in the
+     * access pseudocode for each counter register.
+     */
+    switch (timeridx) {
+    case GTIMER_PHYS:
+        return gt_phys_raw_cnt_offset(env);
+    case GTIMER_VIRT:
+        return env->cp15.cntvoff_el2;
+    case GTIMER_HYP:
+    case GTIMER_SEC:
+    case GTIMER_HYPVIRT:
+        return 0;
+    default:
+        g_assert_not_reached();
+    }
+}
+
 static void gt_recalc_timer(ARMCPU *cpu, int timeridx)
 {
     ARMGenericTimer *gt = &cpu->env.cp15.c14_timer[timeridx];
@@ -2469,8 +2495,7 @@ static void gt_recalc_timer(ARMCPU *cpu, int timeridx)
          * Timer enabled: calculate and set current ISTATUS, irq, and
          * reset timer to when ISTATUS next has to change
          */
-        uint64_t offset = timeridx == GTIMER_VIRT ?
-            cpu->env.cp15.cntvoff_el2 : gt_phys_raw_cnt_offset(&cpu->env);
+        uint64_t offset = gt_indirect_access_timer_offset(&cpu->env, timeridx);
         uint64_t count = gt_get_countervalue(&cpu->env);
         /* Note that this must be unsigned 64 bit arithmetic: */
         int istatus = count - offset >= gt->cval;