diff --git a/os/ports/IAR/ARMCMx/chcore_v6m.c b/os/ports/IAR/ARMCMx/chcore_v6m.c
index dbd2e017a..4c8ab0646 100644
--- a/os/ports/IAR/ARMCMx/chcore_v6m.c
+++ b/os/ports/IAR/ARMCMx/chcore_v6m.c
@@ -88,10 +88,10 @@ void _port_switch_from_irq(void) {
 #define PUSH_CONTEXT(sp) {                                                  \
   asm ("push    {r4, r5, r6, r7, lr}                   \n\t"                \
        "mov     r4, r8                                 \n\t"                \
-        "mov     r5, r9                                \n\t"                \
-        "mov     r6, r10                               \n\t"                \
-        "mov     r7, r11                               \n\t"                \
-        "push    {r4, r5, r6, r7}");                                        \
+       "mov     r5, r9                                 \n\t"                \
+       "mov     r6, r10                                \n\t"                \
+       "mov     r7, r11                                \n\t"                \
+       "push    {r4, r5, r6, r7}");                                         \
 }
 
 #define POP_CONTEXT(sp) {                                                   \
diff --git a/os/ports/IAR/ARMCMx/chcore_v6m.h b/os/ports/IAR/ARMCMx/chcore_v6m.h
index ecf9a8ea7..3c1189ce6 100644
--- a/os/ports/IAR/ARMCMx/chcore_v6m.h
+++ b/os/ports/IAR/ARMCMx/chcore_v6m.h
@@ -80,9 +80,9 @@ struct intctx {
   tp->p_ctx.r13 = (struct intctx *)((uint8_t *)workspace +                  \
                                      wsize -                                \
                                      sizeof(struct intctx));                \
-  tp->p_ctx.r13->r4 = pf;                                                   \
+  tp->p_ctx.r13->r4 = (void *)pf;                                           \
   tp->p_ctx.r13->r5 = arg;                                                  \
-  tp->p_ctx.r13->lr = _port_thread_start;                                   \
+  tp->p_ctx.r13->lr = (void *)_port_thread_start;                           \
 }
 
 /**
@@ -129,18 +129,7 @@ struct intctx {
  * @details This macro must be inserted at the end of all IRQ handlers
  *          enabled to invoke system APIs.
  */
-#define PORT_IRQ_EPILOGUE() {                                               \
-  port_lock_from_isr();                                                     \
-  if ((--_port_irq_nesting == 0) && chSchIsRescRequiredExI()) {             \
-    register struct cmxctx *ctxp;                                           \
-                                                                            \
-    asm volatile ("mrs     %0, PSP" : "=r" (ctxp) : );                      \
-    _port_saved_pc = ctxp->pc;                                              \
-    ctxp->pc = _port_switch_from_irq;                                       \
-    return;                                                                 \
-  }                                                                         \
-  port_unlock_from_isr();                                                   \
-}
+#define PORT_IRQ_EPILOGUE() _port_irq_epilogue()
 
 /**
  * @brief   IRQ handler function declaration.
@@ -171,14 +160,14 @@ struct intctx {
  * @details Usually this function just disables interrupts but may perform
  *          more actions.
  */
-#define port_lock() asm volatile ("cpsid   i" : : : "memory")
+#define port_lock() __disable_interrupt()
 
 /**
  * @brief   Kernel-unlock action.
  * @details Usually this function just disables interrupts but may perform
  *          more actions.
  */
-#define port_unlock() asm volatile ("cpsie   i" : : : "memory")
+#define port_unlock() __enable_interrupt()
 
 /**
  * @brief   Kernel-lock action from an interrupt handler.
@@ -201,17 +190,17 @@ struct intctx {
 /**
  * @brief   Disables all the interrupt sources.
  */
-#define port_disable() asm volatile ("cpsid   i" : : : "memory")
+#define port_disable() __enable_interrupt()
 
 /**
  * @brief   Disables the interrupt sources below kernel-level priority.
  */
-#define port_suspend() asm volatile ("cpsid   i" : : : "memory")
+#define port_suspend() __enable_interrupt()
 
 /**
  * @brief   Enables all the interrupt sources.
  */
-#define port_enable() asm volatile ("cpsie   i" : : : "memory")
+#define port_enable() __enable_interrupt()
 
 /**
  * @brief   Enters an architecture-dependent IRQ-waiting mode.
@@ -222,7 +211,7 @@ struct intctx {
  * @note    Implemented as an inlined @p WFI instruction.
  */
 #if CORTEX_ENABLE_WFI_IDLE || defined(__DOXYGEN__)
-#define port_wait_for_interrupt() asm volatile ("wfi" : : : "memory")
+#define port_wait_for_interrupt() asm ("wfi")
 #else
 #define port_wait_for_interrupt()
 #endif