cmsis_rtos_v1: fix thread instances management.

add a bitarray into struct osThreadDef_t to indicate whether the
thread is used or not, then we can get the first available thread
by searching this array when creating a new thread, and update this
array to add a free thread when terminating a thread.

Signed-off-by: Chen Peng1 <peng1.chen@intel.com>

include/portability/cmsis_os.h

@@ -67,6 +67,7 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <kernel.h>
+#include <sys/bitarray.h>
  
 #ifdef  __cplusplus
 extern "C"
@@ -172,6 +173,8 @@ typedef struct os_thread_def  {
   struct k_poll_signal *poll_signal;
   struct k_poll_event   *poll_event;
   int32_t            signal_results;
+  ///< a bitarray used to indicate whether the thread is used or not, 0: unused, 1: used
+  void                 *status_mask;
 } osThreadDef_t;
  
 /// Timer Definition structure contains timer parameters.
@@ -288,8 +291,11 @@ static K_THREAD_STACK_ARRAY_DEFINE(stacks_##name, instances, CONFIG_CMSIS_THREAD
 static struct k_thread cm_thread_##name[instances]; \
 static struct k_poll_signal wait_signal_##name; \
 static struct k_poll_event wait_events_##name; \
+static SYS_BITARRAY_DEFINE(bitarray_##name, instances); \
 static osThreadDef_t os_thread_def_##name = \
-{ (name), (priority), (instances), (stacksz), (void *)(stacks_##name), (cm_thread_##name), (&wait_signal_##name), (&wait_events_##name), 0 }
+{ (name), (priority), (instances), (stacksz), (void *)(stacks_##name), \
+	(cm_thread_##name), (&wait_signal_##name), \
+	(&wait_events_##name), 0, (void *)(&bitarray_##name)}
 #endif
  
 /// Access a Thread definition.

kernel/sched.c

@@ -1460,6 +1460,10 @@ static inline void unpend_all(_wait_q_t *wait_q)
 	}
 }
 
+#ifdef CONFIG_CMSIS_RTOS_V1
+extern void z_thread_cmsis_status_mask_clear(struct k_thread *thread);
+#endif
+
 static void end_thread(struct k_thread *thread)
 {
 	/* We hold the lock, and the thread is known not to be running
@@ -1482,6 +1486,10 @@ static void end_thread(struct k_thread *thread)
 
 		z_thread_monitor_exit(thread);
 
+#ifdef CONFIG_CMSIS_RTOS_V1
+		z_thread_cmsis_status_mask_clear(thread);
+#endif
+
 #ifdef CONFIG_USERSPACE
 		z_mem_domain_exit_thread(thread);
 		z_thread_perms_all_clear(thread);

subsys/portability/cmsis_rtos_v1/Kconfig

@@ -5,6 +5,7 @@ config CMSIS_RTOS_V1
 	bool "CMSIS RTOS v1 API"
 	depends on THREAD_CUSTOM_DATA
 	depends on POLL
+	depends on THREAD_STACK_INFO
 	help
 	  This enables CMSIS RTOS v1 API support. This is an OS-integration
 	  layer which allows applications using CMSIS RTOS APIs to build on

subsys/portability/cmsis_rtos_v1/cmsis_thread.c

@@ -34,6 +34,23 @@ static void zephyr_thread_wrapper(void *arg1, void *arg2, void *arg3)
 	fun_ptr(arg1);
 }
 
+/* clear related bit in cmsis thread status bitarray
+ * when terminating a thread
+ */
+void z_thread_cmsis_status_mask_clear(struct k_thread *thread)
+{
+	uint32_t offset, instance;
+
+	osThreadDef_t *thread_def = (osThreadDef_t *)(thread->custom_data);
+
+	if (thread_def != NULL) {
+		/* get thread instance index according to stack address */
+		offset = thread->stack_info.start - (uintptr_t)thread_def->stack_mem;
+		instance = offset / K_THREAD_STACK_LEN(CONFIG_CMSIS_THREAD_MAX_STACK_SIZE);
+		sys_bitarray_clear_bit((sys_bitarray_t *)(thread_def->status_mask), instance);
+	}
+}
+
 /**
  * @brief Create a new thread.
  */
@@ -43,6 +60,8 @@ osThreadId osThreadCreate(const osThreadDef_t *thread_def, void *arg)
 	uint32_t prio;
 	k_tid_t tid;
 	uint32_t stacksz;
+	int ret;
+	size_t instance;
 
 	k_thread_stack_t
 	   (*stk_ptr)[K_THREAD_STACK_LEN(CONFIG_CMSIS_THREAD_MAX_STACK_SIZE)];
@@ -67,6 +86,13 @@ osThreadId osThreadCreate(const osThreadDef_t *thread_def, void *arg)
 		 (thread_def->tpriority <= osPriorityRealtime),
 		 "invalid priority\n");
 
+	/* get an available thread instance */
+	ret = sys_bitarray_alloc((sys_bitarray_t *)(thread_def->status_mask),
+			1, &instance);
+	if (ret != 0) {
+		return NULL;
+	}
+
 	stacksz = thread_def->stacksize;
 	if (stacksz == 0U) {
 		stacksz = CONFIG_CMSIS_THREAD_MAX_STACK_SIZE;
@@ -77,17 +103,22 @@ osThreadId osThreadCreate(const osThreadDef_t *thread_def, void *arg)
 			K_POLL_MODE_NOTIFY_ONLY, thread_def->poll_signal);
 
 	cm_thread = thread_def->cm_thread;
-	atomic_dec((atomic_t *)&thread_def->instances);
 	stk_ptr = thread_def->stack_mem;
 	prio = cmsis_to_zephyr_priority(thread_def->tpriority);
 	k_thread_custom_data_set((void *)thread_def);
 
-	tid = k_thread_create(&cm_thread[thread_def->instances],
-			stk_ptr[thread_def->instances], stacksz,
+	tid = k_thread_create(&cm_thread[instance],
+			stk_ptr[instance], stacksz,
 			(k_thread_entry_t)zephyr_thread_wrapper,
 			(void *)arg, NULL, thread_def->pthread,
 			prio, 0, K_NO_WAIT);
 
+	/* make custom_data pointer of thread point to its source thread_def,
+	 * then we can use it to release thread instances
+	 * when terminating threads
+	 */
+	tid->custom_data = (void *)thread_def;
+
 	return ((osThreadId)tid);
 }
 

tests/subsys/portability/cmsis_rtos_v1/prj.conf

@@ -6,3 +6,4 @@ CONFIG_MAX_THREAD_BYTES=4
 CONFIG_IRQ_OFFLOAD=y
 CONFIG_CMSIS_THREAD_MAX_STACK_SIZE=2048
 CONFIG_SMP=n
+CONFIG_THREAD_STACK_INFO=y

tests/subsys/portability/cmsis_rtos_v1/src/thread_instance.c

@@ -26,6 +26,7 @@ osThreadDef(thread_inst_check, osPriorityNormal, 3, STACKSZ);
 void test_thread_instances(void)
 {
 	osThreadId id1, id2, id3, id4;
+	osStatus status;
 
 	id1 = osThreadCreate(osThread(thread_inst_check), NULL);
 	zassert_true(id1 != NULL, "Failed creating thread_inst_check");
@@ -38,4 +39,14 @@ void test_thread_instances(void)
 
 	id4 = osThreadCreate(osThread(thread_inst_check), NULL);
 	zassert_true(id4 == NULL, "Something wrong with thread instances");
+
+	status = osThreadTerminate(id2);
+	zassert_true(status == osOK, "Error terminating thread_inst_check");
+
+	/* after terminating thread id2, when creating a new thread,
+	 * it should re-use the available thread instance of id2.
+	 */
+	id4 = osThreadCreate(osThread(thread_inst_check), NULL);
+	zassert_true(id4 != NULL, "Failed creating thread_inst_check");
+	zassert_true(id2 == id4, "Error creating thread_inst_check");
 }