diff --git a/cpu/cortexm_common/include/cpu.h b/cpu/cortexm_common/include/cpu.h
index ae8c812a3a..b8e7e29e79 100644
--- a/cpu/cortexm_common/include/cpu.h
+++ b/cpu/cortexm_common/include/cpu.h
@@ -76,7 +76,7 @@ static inline void cpu_print_last_instruction(void)
  * This function is meant to be used for short periods of time, where it is not
  * feasible to switch to the idle thread and back.
  */
-static inline void cpu_sleep_until_event(void)
+static inline void cortexm_sleep_until_event(void)
 {
     __WFE();
 }
diff --git a/cpu/nrf5x_common/periph/hwrng.c b/cpu/nrf5x_common/periph/hwrng.c
index ab3eb3ee2e..b9fb565608 100644
--- a/cpu/nrf5x_common/periph/hwrng.c
+++ b/cpu/nrf5x_common/periph/hwrng.c
@@ -44,7 +44,7 @@ void hwrng_read(void *buf, unsigned int num)
     while (count < num) {
         /* sleep until number is generated */
         while (NRF_RNG->EVENTS_VALRDY == 0) {
-            cpu_sleep_until_event();
+            cortexm_sleep_until_event();
         }
 
         b[count++] = (uint8_t)NRF_RNG->VALUE;