diff --git a/target/arm/helper.c b/target/arm/helper.c
index 49665bb763..e068d35383 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -954,11 +954,13 @@ static bool instructions_supported(CPUARMState *env)
 
 static uint64_t instructions_get_count(CPUARMState *env)
 {
+    assert(icount_enabled() == ICOUNT_PRECISE);
     return (uint64_t)icount_get_raw();
 }
 
 static int64_t instructions_ns_per(uint64_t icount)
 {
+    assert(icount_enabled() == ICOUNT_PRECISE);
     return icount_to_ns((int64_t)icount);
 }
 #endif