2 * @brief Thread functions.
10 #include "threads-model.h"
13 /* global "model" object */
15 #include "execution.h"
19 uintptr_t get_tls_addr() {
21 asm ("mov %%fs:0, %0" : "=r" (addr));
25 #include <asm/prctl.h>
26 #include <sys/prctl.h>
28 int arch_prctl(int code, unsigned long addr);
30 static void set_tls_addr(uintptr_t addr) {
31 arch_prctl(ARCH_SET_FS, addr);
32 asm ("mov %0, %%fs:0" : : "r" (addr) : "memory");
36 /** Allocate a stack for a new thread. */
37 static void * stack_allocate(size_t size)
39 return Thread_malloc(size);
42 /** Free a stack for a terminated thread. */
43 static void stack_free(void *stack)
49 * @brief Get the current Thread
51 * Must be called from a user context
53 * @return The currently executing thread
55 Thread * thread_current(void)
58 return model->get_current_thread();
61 void main_thread_startup() {
63 Thread * curr_thread = thread_current();
64 /* Add dummy "start" action, just to create a first clock vector */
65 model->switch_to_master(new ModelAction(THREAD_START, std::memory_order_seq_cst, curr_thread));
71 * Provides a startup wrapper for each thread, allowing some initial
72 * model-checking data to be recorded. This method also gets around makecontext
73 * not being 64-bit clean
77 Thread * curr_thread = thread_current();
79 /* Add dummy "start" action, just to create a first clock vector */
80 model->switch_to_master(new ModelAction(THREAD_START, std::memory_order_seq_cst, curr_thread));
83 /* Call the actual thread function */
84 if (curr_thread->start_routine != NULL) {
85 curr_thread->start_routine(curr_thread->arg);
86 } else if (curr_thread->pstart_routine != NULL) {
87 // set pthread return value
88 void *retval = curr_thread->pstart_routine(curr_thread->arg);
89 curr_thread->set_pthread_return(retval);
91 /* Finish thread properly */
92 model->switch_to_master(new ModelAction(THREAD_FINISH, std::memory_order_seq_cst, curr_thread));
95 static int (*pthread_mutex_init_p)(pthread_mutex_t *__mutex, const pthread_mutexattr_t *__mutexattr) = NULL;
97 int real_pthread_mutex_init(pthread_mutex_t *__mutex, const pthread_mutexattr_t *__mutexattr) {
98 return pthread_mutex_init_p(__mutex, __mutexattr);
101 static int (*pthread_mutex_lock_p) (pthread_mutex_t *__mutex) = NULL;
103 int real_pthread_mutex_lock (pthread_mutex_t *__mutex) {
104 return pthread_mutex_lock_p(__mutex);
107 static int (*pthread_mutex_unlock_p) (pthread_mutex_t *__mutex) = NULL;
109 int real_pthread_mutex_unlock (pthread_mutex_t *__mutex) {
110 return pthread_mutex_unlock_p(__mutex);
113 static int (*pthread_create_p) (pthread_t *__restrict, const pthread_attr_t *__restrict, void *(*)(void *), void * __restrict) = NULL;
115 int real_pthread_create (pthread_t *__restrict __newthread, const pthread_attr_t *__restrict __attr, void *(*__start_routine)(void *), void *__restrict __arg) {
116 return pthread_create_p(__newthread, __attr, __start_routine, __arg);
119 static int (*pthread_join_p) (pthread_t __th, void ** __thread_return) = NULL;
121 int real_pthread_join (pthread_t __th, void ** __thread_return) {
122 return pthread_join_p(__th, __thread_return);
125 static void (*pthread_exit_p)(void *) __attribute__((noreturn))= NULL;
127 void real_pthread_exit (void * value_ptr) {
128 pthread_exit_p(value_ptr);
131 void real_init_all() {
133 if (!pthread_mutex_init_p) {
134 pthread_mutex_init_p = (int (*)(pthread_mutex_t *__mutex, const pthread_mutexattr_t *__mutexattr))dlsym(RTLD_NEXT, "pthread_mutex_init");
135 if ((error = dlerror()) != NULL) {
136 fputs(error, stderr);
140 if (!pthread_mutex_lock_p) {
141 pthread_mutex_lock_p = (int (*)(pthread_mutex_t *__mutex))dlsym(RTLD_NEXT, "pthread_mutex_lock");
142 if ((error = dlerror()) != NULL) {
143 fputs(error, stderr);
147 if (!pthread_mutex_unlock_p) {
148 pthread_mutex_unlock_p = (int (*)(pthread_mutex_t *__mutex))dlsym(RTLD_NEXT, "pthread_mutex_unlock");
149 if ((error = dlerror()) != NULL) {
150 fputs(error, stderr);
154 if (!pthread_create_p) {
155 pthread_create_p = (int (*)(pthread_t *__restrict, const pthread_attr_t *__restrict, void *(*)(void *), void *__restrict))dlsym(RTLD_NEXT, "pthread_create");
156 if ((error = dlerror()) != NULL) {
157 fputs(error, stderr);
161 if (!pthread_join_p) {
162 pthread_join_p = (int (*)(pthread_t __th, void ** __thread_return))dlsym(RTLD_NEXT, "pthread_join");
163 if ((error = dlerror()) != NULL) {
164 fputs(error, stderr);
169 if (!pthread_exit_p) {
170 pthread_exit_p = (void (*)(void *))dlsym(RTLD_NEXT, "pthread_exit");
171 if ((error = dlerror()) != NULL) {
172 fputs(error, stderr);
179 void finalize_helper_thread() {
180 Thread * curr_thread = thread_current();
181 real_pthread_mutex_lock(&curr_thread->mutex);
182 curr_thread->tls = (char *) get_tls_addr();
183 real_pthread_mutex_unlock(&curr_thread->mutex);
184 //Wait in the kernel until it is time for us to finish
185 real_pthread_mutex_lock(&curr_thread->mutex2);
186 real_pthread_mutex_unlock(&curr_thread->mutex2);
187 //return to helper thread function
188 setcontext(&curr_thread->context);
191 void * helper_thread(void * ptr) {
192 Thread * curr_thread = thread_current();
194 //build a context for this real thread so we can take it's context
195 int ret = getcontext(&curr_thread->helpercontext);
198 /* Initialize new managed context */
199 void *helperstack = stack_allocate(STACK_SIZE);
200 curr_thread->helpercontext.uc_stack.ss_sp = helperstack;
201 curr_thread->helpercontext.uc_stack.ss_size = STACK_SIZE;
202 curr_thread->helpercontext.uc_stack.ss_flags = 0;
203 curr_thread->helpercontext.uc_link = model->get_system_context();
204 makecontext(&curr_thread->helpercontext, finalize_helper_thread, 0);
206 model_swapcontext(&curr_thread->context, &curr_thread->helpercontext);
208 //start the real thread
211 //now the real thread has control again
212 stack_free(helperstack);
217 void setup_context() {
218 Thread * curr_thread = thread_current();
220 /* Add dummy "start" action, just to create a first clock vector */
221 model->switch_to_master(new ModelAction(THREAD_START, std::memory_order_seq_cst, curr_thread));
225 /* Initialize our lock */
226 real_pthread_mutex_init(&curr_thread->mutex, NULL);
227 real_pthread_mutex_init(&curr_thread->mutex2, NULL);
228 real_pthread_mutex_lock(&curr_thread->mutex2);
230 /* Create the real thread */
231 real_pthread_create(&curr_thread->thread, NULL, helper_thread, NULL);
234 real_pthread_mutex_lock(&curr_thread->mutex);
235 if (curr_thread->tls != NULL)
237 real_pthread_mutex_unlock(&curr_thread->mutex);
240 set_tls_addr((uintptr_t)curr_thread->tls);
241 setcontext(&curr_thread->context);
246 * Create a thread context for a new thread so we can use
247 * setcontext/getcontext/swapcontext to swap it out.
248 * @return 0 on success; otherwise, non-zero error condition
250 int Thread::create_context()
254 ret = getcontext(&context);
258 /* Initialize new managed context */
259 stack = stack_allocate(STACK_SIZE);
260 context.uc_stack.ss_sp = stack;
261 context.uc_stack.ss_size = STACK_SIZE;
262 context.uc_stack.ss_flags = 0;
263 context.uc_link = model->get_system_context();
266 makecontext(&context, setup_context, 0);
268 makecontext(&context, main_thread_startup, 0);
270 makecontext(&context, thread_startup, 0);
277 * Swaps the current context to another thread of execution. This form switches
278 * from a user Thread to a system context.
279 * @param t Thread representing the currently-running thread. The current
280 * context is saved here.
281 * @param ctxt Context to which we will swap. Must hold a valid system context.
282 * @return Does not return, unless we return to Thread t's context. See
283 * swapcontext(3) (returns 0 for success, -1 for failure).
285 int Thread::swap(Thread *t, ucontext_t *ctxt)
287 t->set_state(THREAD_READY);
289 set_tls_addr((uintptr_t)model->getInitThread()->tls);
291 return model_swapcontext(&t->context, ctxt);
295 * Swaps the current context to another thread of execution. This form switches
296 * from a system context to a user Thread.
297 * @param ctxt System context variable to which to save the current context.
298 * @param t Thread to which we will swap. Must hold a valid user context.
299 * @return Does not return, unless we return to the system context (ctxt). See
300 * swapcontext(3) (returns 0 for success, -1 for failure).
302 int Thread::swap(ucontext_t *ctxt, Thread *t)
304 t->set_state(THREAD_RUNNING);
307 set_tls_addr((uintptr_t)t->tls);
309 return model_swapcontext(ctxt, &t->context);
313 /** Terminate a thread and free its stack. */
314 void Thread::complete()
316 ASSERT(!is_complete());
317 DEBUG("completed thread %d\n", id_to_int(get_id()));
318 state = THREAD_COMPLETED;
322 if (this != model->getInitThread()) {
324 real_pthread_mutex_unlock(&mutex2);
325 real_pthread_join(thread, NULL);
332 * @brief Construct a new model-checker Thread
334 * A model-checker Thread is used for accounting purposes only. It will never
335 * have its own stack, and it should never be inserted into the Scheduler.
337 * @param tid The thread ID to assign
339 Thread::Thread(thread_id_t tid) :
351 state(THREAD_READY), /* Thread is always ready? */
355 memset(&context, 0, sizeof(context));
359 * Construct a new thread.
360 * @param t The thread identifier of the newly created thread.
361 * @param func The function that the thread will call.
362 * @param a The parameter to pass to this function.
364 Thread::Thread(thread_id_t tid, thrd_t *t, void (*func)(void *), void *a, Thread *parent) :
369 pstart_routine(NULL),
376 state(THREAD_CREATED),
377 last_action_val(VALUE_NONE),
382 /* Initialize state */
383 ret = create_context();
385 model_print("Error in create_context\n");
387 user_thread->priv = this; // WL
391 * Construct a new thread for pthread.
392 * @param t The thread identifier of the newly created thread.
393 * @param func The function that the thread will call.
394 * @param a The parameter to pass to this function.
396 Thread::Thread(thread_id_t tid, thrd_t *t, void *(*func)(void *), void *a, Thread *parent) :
401 pstart_routine(func),
408 state(THREAD_CREATED),
409 last_action_val(VALUE_NONE),
414 /* Initialize state */
415 ret = create_context();
417 model_print("Error in create_context\n");
428 /** @return The thread_id_t corresponding to this Thread object. */
429 thread_id_t Thread::get_id() const
435 * Set a thread's THREAD_* state (@see thread_state)
436 * @param s The state to enter
438 void Thread::set_state(thread_state s)
440 ASSERT(s == THREAD_COMPLETED || state != THREAD_COMPLETED);
445 * Get the Thread that this Thread is immediately waiting on
446 * @return The thread we are waiting on, if any; otherwise NULL
448 Thread * Thread::waiting_on() const
453 if (pending->get_type() == THREAD_JOIN)
454 return pending->get_thread_operand();
455 else if (pending->get_type() == PTHREAD_JOIN)
456 return pending->get_thread_operand();
457 else if (pending->is_lock())
458 return (Thread *)pending->get_mutex()->get_state()->locked;
463 * Check if this Thread is waiting (blocking) on a given Thread, directly or
464 * indirectly (via a chain of waiting threads)
466 * @param t The Thread on which we may be waiting
467 * @return True if we are waiting on Thread t; false otherwise
469 bool Thread::is_waiting_on(const Thread *t) const
472 for (wait = waiting_on();wait != NULL;wait = wait->waiting_on())