Add RTX API to enumerate running threads

Add the functions osThreadsEnumStart, osThreadEnumNext and
osThreadEnumFree to allow enumeration of running threads. Protect
thread creation, thread exit and thread termination with a mutex
so threads are not created or destroyed while an enumeration is
ongoing.

rtos/rtx/TARGET_CORTEX_A/cmsis_os.h

@@ -160,6 +160,7 @@ used throughout the whole project.
 #define osFeature_Semaphore    65535   ///< maximum count for \ref osSemaphoreCreate function
 #define osFeature_Wait         0       ///< osWait function: 1=available, 0=not available
 #define osFeature_SysTick      1       ///< osKernelSysTick functions: 1=available, 0=not available
+#define osFeature_ThreadEnum   1       ///< Thread enumeration available
 
 #if defined (__CC_ARM)
 #define os_InRegs __value_in_regs      // Compiler specific: force struct in registers
@@ -261,6 +262,8 @@ typedef struct os_messageQ_cb *osMessageQId;
 /// \note CAN BE CHANGED: \b os_mailQ_cb is implementation specific in every CMSIS-RTOS.
 typedef struct os_mailQ_cb *osMailQId;
 
+/// Thread enumeration ID identifies the enumeration (pointer to a thread enumeration control block).
+typedef uint32_t *osThreadEnumId;
 
 /// Thread Definition structure contains startup information of a thread.
 /// \note CAN BE CHANGED: \b os_thread_def is implementation specific in every CMSIS-RTOS.
@@ -823,6 +826,26 @@ osStatus osMailFree (osMailQId queue_id, void *mail);
 #endif  // Mail Queues available
 
 
+//  ==== Thread Enumeration Functions ====
+
+#if (defined (osFeature_ThreadEnum)  &&  (osFeature_ThreadEnum != 0))     // Thread enumeration available
+
+/// Start a thread enumeration.
+/// \return an enumeration ID or NULL on error.
+osThreadEnumId osThreadsEnumStart(void);
+
+/// Get the next task ID in the enumeration.
+/// \return a thread ID or NULL on if the end of the enumeration has been reached.
+osThreadId osThreadEnumNext(osThreadEnumId enum_id);
+
+/// Free the enumeration structure.
+/// \param[in]     enum_id       pointer to the enumeration ID that was obtained with \ref osThreadsEnumStart.
+/// \return status code that indicates the execution status of the function.
+osStatus osThreadEnumFree(osThreadEnumId enum_id);
+
+#endif  // Thread Enumeration available
+
+
 //  ==== RTX Extensions ====
 
 /// os_suspend: http://www.keil.com/support/man/docs/rlarm/rlarm_os_suspend.htm

rtos/rtx/TARGET_CORTEX_A/rt_CMSIS.c

@@ -479,6 +479,9 @@ extern       osMessageQId    osMessageQId_osTimerMessageQ;
 
 extern U32 IRQNestLevel; /* Indicates whether inside an ISR, and the depth of nesting.  0 = not in ISR. */
 
+// Thread creation and destruction mutex
+osMutexDef(osThreadMutex);
+osMutexId osMutexId_osThreadMutex;
 
 // ==== Helper Functions ====
 
@@ -596,6 +599,8 @@ osStatus svcKernelInitialize (void) {
     // Create OS Timers resources (Message Queue & Thread)
     osMessageQId_osTimerMessageQ = svcMessageCreate (&os_messageQ_def_osTimerMessageQ, NULL);
     osThreadId_osTimerThread = svcThreadCreate(&os_thread_def_osTimerThread, NULL);
+    // Initialize thread mutex
+    osMutexId_osThreadMutex = osMutexCreate(osMutex(osThreadMutex));
   }
 
   sysThreadError(osOK);
@@ -856,7 +861,12 @@ osThreadId osThreadCreate (const osThreadDef_t *thread_def, void *argument) {
     // Privileged and not running
     return   svcThreadCreate(thread_def, argument);
   } else {
-    return __svcThreadCreate(thread_def, argument);
+    osThreadId id;
+    osMutexWait(osMutexId_osThreadMutex, osWaitForever);
+    // Thread mutex must be held when a thread is created or terminated
+    id = __svcThreadCreate(thread_def, argument);
+    osMutexRelease(osMutexId_osThreadMutex);
+    return id;
   }
 }
 
@@ -868,8 +878,13 @@ osThreadId osThreadGetId (void) {
 
 /// Terminate execution of a thread and remove it from ActiveThreads
 osStatus osThreadTerminate (osThreadId thread_id) {
+  osStatus status;
   if (__exceptional_mode()) return osErrorISR;     // Not allowed in ISR
-  return __svcThreadTerminate(thread_id);
+  osMutexWait(osMutexId_osThreadMutex, osWaitForever);
+  // Thread mutex must be held when a thread is created or terminated
+  status = __svcThreadTerminate(thread_id);
+  osMutexRelease(osMutexId_osThreadMutex);
+  return status;
 }
 
 /// Pass control to next thread that is in state READY
@@ -893,6 +908,10 @@ osPriority osThreadGetPriority (osThreadId thread_id) {
 /// INTERNAL - Not Public
 /// Auto Terminate Thread on exit (used implicitly when thread exists)
 __NO_RETURN void osThreadExit (void) {
+  // Thread mutex must be held when a thread is created or terminated
+  // Note - the mutex will be released automatically by the os when
+  //        the thread is terminated
+  osMutexWait(osMutexId_osThreadMutex, osWaitForever);
   __svcThreadTerminate(__svcThreadGetId());
   for (;;);                                     // Should never come here
 }
@@ -911,6 +930,38 @@ uint8_t osThreadGetState (osThreadId thread_id) {
 }
 #endif
 
+osThreadEnumId osThreadsEnumStart() {
+  static uint32_t thread_enum_index;
+  osMutexWait(osMutexId_osThreadMutex, osWaitForever);
+  thread_enum_index = 0;
+  return &thread_enum_index;
+}
+
+osThreadId osThreadEnumNext(osThreadEnumId enum_id) {
+  uint32_t i;
+  osThreadId id = NULL;
+  uint32_t *index = (uint32_t*)enum_id;
+  for (i = *index; i < os_maxtaskrun; i++) {
+    if (os_active_TCB[i] != NULL) {
+      id = (osThreadId)os_active_TCB[i];
+      break;
+    }
+  }
+  if (i == os_maxtaskrun) {
+    // Include the idle task at the end of the enumeration
+    id = &os_idle_TCB;
+  }
+  *index = i + 1;
+  return id;
+}
+
+osStatus osThreadEnumFree(osThreadEnumId enum_id) {
+  uint32_t *index = (uint32_t*)enum_id;
+  *index = 0;
+  osMutexRelease(osMutexId_osThreadMutex);
+  return osOK;
+}
+
 // ==== Generic Wait Functions ====
 
 // Generic Wait Service Calls declarations

rtos/rtx/TARGET_CORTEX_M/cmsis_os.h

@@ -99,6 +99,7 @@
 #define osFeature_Semaphore    65535   ///< Maximum count for \ref osSemaphoreCreate function
 #define osFeature_Wait         0       ///< osWait not available
 #define osFeature_SysTick      1       ///< osKernelSysTick functions available
+#define osFeature_ThreadEnum   1       ///< Thread enumeration available
 
 #if defined (__CC_ARM)
 #define os_InRegs __value_in_regs      // Compiler specific: force struct in registers
@@ -188,6 +189,8 @@ typedef struct os_messageQ_cb *osMessageQId;
 /// Mail ID identifies the mail queue (pointer to a mail queue control block).
 typedef struct os_mailQ_cb *osMailQId;
 
+/// Thread enumeration ID identifies the enumeration (pointer to a thread enumeration control block).
+typedef uint32_t *osThreadEnumId;
 
 /// Thread Definition structure contains startup information of a thread.
 typedef struct os_thread_def  {
@@ -680,6 +683,26 @@ osStatus osMailFree (osMailQId queue_id, void *mail);
 #endif  // Mail Queues available
 
 
+//  ==== Thread Enumeration Functions ====
+
+#if (defined (osFeature_ThreadEnum)  &&  (osFeature_ThreadEnum != 0))     // Thread enumeration available
+
+/// Start a thread enumeration.
+/// \return an enumeration ID or NULL on error.
+osThreadEnumId osThreadsEnumStart(void);
+
+/// Get the next task ID in the enumeration.
+/// \return a thread ID or NULL on if the end of the enumeration has been reached.
+osThreadId osThreadEnumNext(osThreadEnumId enum_id);
+
+/// Free the enumeration structure.
+/// \param[in]     enum_id       pointer to the enumeration ID that was obtained with \ref osThreadsEnumStart.
+/// \return status code that indicates the execution status of the function.
+osStatus osThreadEnumFree(osThreadEnumId enum_id);
+
+#endif  // Thread Enumeration available
+
+
 //  ==== RTX Extensions ====
 
 /// Suspend the RTX task scheduler.

rtos/rtx/TARGET_CORTEX_M/rt_CMSIS.c

@@ -392,6 +392,9 @@ extern       osThreadId      osThreadId_osTimerThread;
 extern const osMessageQDef_t os_messageQ_def_osTimerMessageQ;
 extern       osMessageQId    osMessageQId_osTimerMessageQ;
 
+// Thread creation and destruction mutex
+osMutexDef(osThreadMutex);
+osMutexId osMutexId_osThreadMutex;
 
 // ==== Helper Functions ====
 
@@ -490,6 +493,8 @@ osStatus svcKernelInitialize (void) {
     // Create OS Timers resources (Message Queue & Thread)
     osMessageQId_osTimerMessageQ = svcMessageCreate (&os_messageQ_def_osTimerMessageQ, NULL);
     osThreadId_osTimerThread = svcThreadCreate(&os_thread_def_osTimerThread, NULL, NULL);
+    // Initialize thread mutex
+    osMutexId_osThreadMutex = osMutexCreate(osMutex(osThreadMutex));
   }
 
   sysThreadError(osOK);
@@ -806,7 +811,12 @@ osThreadId osThreadContextCreate (const osThreadDef_t *thread_def, void *argumen
     // Privileged and not running
     return   svcThreadCreate(thread_def, argument, context);
   } else {
-    return __svcThreadCreate(thread_def, argument, context);
+    osThreadId id;
+    osMutexWait(osMutexId_osThreadMutex, osWaitForever);
+    // Thread mutex must be held when a thread is created or terminated
+    id = __svcThreadCreate(thread_def, argument, context);
+    osMutexRelease(osMutexId_osThreadMutex);
+    return id;
   }
 }
 
@@ -820,10 +830,15 @@ osThreadId osThreadGetId (void) {
 
 /// Terminate execution of a thread and remove it from ActiveThreads
 osStatus osThreadTerminate (osThreadId thread_id) {
+  osStatus status;
   if (__get_IPSR() != 0U) { 
     return osErrorISR;                          // Not allowed in ISR
   }
-  return __svcThreadTerminate(thread_id);
+  osMutexWait(osMutexId_osThreadMutex, osWaitForever);
+  // Thread mutex must be held when a thread is created or terminated
+  status = __svcThreadTerminate(thread_id);
+  osMutexRelease(osMutexId_osThreadMutex);
+  return status;
 }
 
 /// Pass control to next thread that is in state READY
@@ -852,8 +867,12 @@ osPriority osThreadGetPriority (osThreadId thread_id) {
 
 /// INTERNAL - Not Public
 /// Auto Terminate Thread on exit (used implicitly when thread exists)
-__NO_RETURN void osThreadExit (void) { 
-  __svcThreadTerminate(__svcThreadGetId()); 
+__NO_RETURN void osThreadExit (void) {
+  // Thread mutex must be held when a thread is created or terminated
+  // Note - the mutex will be released automatically by the os when
+  //        the thread is terminated
+  osMutexWait(osMutexId_osThreadMutex, osWaitForever);
+  __svcThreadTerminate(__svcThreadGetId());
   for (;;);                                     // Should never come here
 }
 
@@ -871,6 +890,38 @@ uint8_t osThreadGetState (osThreadId thread_id) {
 }
 #endif
 
+osThreadEnumId osThreadsEnumStart() {
+  static uint32_t thread_enum_index;
+  osMutexWait(osMutexId_osThreadMutex, osWaitForever);
+  thread_enum_index = 0;
+  return &thread_enum_index;
+}
+
+osThreadId osThreadEnumNext(osThreadEnumId enum_id) {
+  uint32_t i;
+  osThreadId id = NULL;
+  uint32_t *index = (uint32_t*)enum_id;
+  for (i = *index; i < os_maxtaskrun; i++) {
+    if (os_active_TCB[i] != NULL) {
+      id = (osThreadId)os_active_TCB[i];
+      break;
+    }
+  }
+  if (i == os_maxtaskrun) {
+    // Include the idle task at the end of the enumeration
+    id = &os_idle_TCB;
+  }
+  *index = i + 1;
+  return id;
+}
+
+osStatus osThreadEnumFree(osThreadEnumId enum_id) {
+  uint32_t *index = (uint32_t*)enum_id;
+  *index = 0;
+  osMutexRelease(osMutexId_osThreadMutex);
+  return osOK;
+}
+
 // ==== Generic Wait Functions ====
 
 // Generic Wait Service Calls declarations