Move in_critical_section implementation into the HAL

- Add function to HAL hal_in_critical_section()
- Wrap assert in FEATURE_UVISOR macro

Author: Steven Cartmell

features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_MCU_NRF51822/hal_patch/critical_section_api.c

@@ -77,3 +77,8 @@ void hal_critical_section_exit(void)
         __set_PRIMASK(_state._PRIMASK_state);
     }
 }
+
+bool hal_in_critical_section(void)
+{
+    return (_state_saved == true);
+}

hal/critical_section_api.h

@@ -18,6 +18,8 @@
 #ifndef MBED_CRITICAL_SECTION_API_H
 #define MBED_CRITICAL_SECTION_API_H
 
+#include <stdbool.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -60,6 +62,7 @@ extern "C" {
  */
 void hal_critical_section_enter(void);
 
+
 /** Mark the end of a critical section.
  *
  * The purpose of this function is to restore any state that was modified upon
@@ -79,6 +82,20 @@ void hal_critical_section_enter(void);
  */
 void hal_critical_section_exit(void);
 
+
+/** Determine if the application is currently running in a critical section
+ *
+ * The purpose of this function is to inform the caller whether or not the
+ * application is running in a critical section. This is done by checking if
+ * the current interrupt state has been saved in the underlying implementation,
+ * this could also be done by checking the state of the interrupts at the time
+ * of calling.
+ *
+ *  @return  True if running in a critical section, false if not.
+ */
+bool hal_in_critical_section(void);
+
+
 /**@}*/
 
 #ifdef __cplusplus

hal/mbed_critical_section_api.c

@@ -47,15 +47,21 @@ MBED_WEAK void hal_critical_section_enter(void)
     state_saved = true;
 }
 
-MBED_WEAK void hal_critical_section_exit()
+MBED_WEAK void hal_critical_section_exit(void)
 {
+#ifndef FEATURE_UVISOR
     // Interrupts must be disabled on invoking an exit from a critical section
     MBED_ASSERT(!are_interrupts_enabled());
-
+#endif
     state_saved = false;
 
     // Restore the IRQs to their state prior to entering the critical section
     if (critical_interrupts_enabled == true) {
         __enable_irq();
     }
 }
+
+MBED_WEAK bool hal_in_critical_section(void)
+{
+    return (state_saved == true);
+}

platform/mbed_critical.c

@@ -53,7 +53,7 @@ bool core_util_is_isr_active(void)
 
 bool core_util_in_critical_section(void)
 {
-    return (critical_section_reentrancy_counter != 0);
+    return hal_in_critical_section();
 }
 
 void core_util_critical_section_enter(void)

targets/TARGET_NORDIC/TARGET_NRF5/critical_section_api.c

@@ -25,7 +25,7 @@ static void nordic_nvic_critical_region_enter(void);
 static void nordic_nvic_critical_region_exit(void);
 #endif
 
-void core_util_critical_section_enter()
+void hal_critical_section_enter()
 {
 #ifdef NRF52
     ASSERT(APP_LEVEL_PRIVILEGED == privilege_level_get())
@@ -39,7 +39,7 @@ void core_util_critical_section_enter()
 #endif
 }
 
-void core_util_critical_section_exit()
+void hal_critical_section_exit()
 {
 #ifdef NRF52
     ASSERT(APP_LEVEL_PRIVILEGED == privilege_level_get())
@@ -53,6 +53,13 @@ void core_util_critical_section_exit()
 #endif
 }
 
+
+bool hal_in_critical_section(void)
+{
+    return (nordic_cr_nested != 0);
+}
+
+
 #if defined(SOFTDEVICE_PRESENT)
 /**@brief Enters critical region.
  *