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));
96 int real_pthread_mutex_init(pthread_mutex_t *__mutex, const pthread_mutexattr_t *__mutexattr) {
97 static int (*pthread_mutex_init_p) (pthread_mutex_t *__mutex, const pthread_mutexattr_t *__mutexattr) = NULL;
99 if (!pthread_mutex_init_p) {
100 pthread_mutex_init_p = (int (*)(pthread_mutex_t *__mutex, const pthread_mutexattr_t *__mutexattr))dlsym(RTLD_NEXT, "pthread_mutex_init");
101 if ((error = dlerror()) != NULL) {
102 fputs(error, stderr);
106 return pthread_mutex_init_p(__mutex, __mutexattr);
109 int real_pthread_mutex_lock (pthread_mutex_t *__mutex) {
110 static int (*pthread_mutex_lock_p) (pthread_mutex_t *__mutex) = NULL;
112 if (!pthread_mutex_lock_p) {
113 pthread_mutex_lock_p = (int (*)(pthread_mutex_t *__mutex))dlsym(RTLD_NEXT, "pthread_mutex_lock");
114 if ((error = dlerror()) != NULL) {
115 fputs(error, stderr);
119 return pthread_mutex_lock_p(__mutex);
122 int real_pthread_mutex_unlock (pthread_mutex_t *__mutex) {
123 static int (*pthread_mutex_unlock_p) (pthread_mutex_t *__mutex) = NULL;
125 if (!pthread_mutex_unlock_p) {
126 pthread_mutex_unlock_p = (int (*)(pthread_mutex_t *__mutex))dlsym(RTLD_NEXT, "pthread_mutex_unlock");
127 if ((error = dlerror()) != NULL) {
128 fputs(error, stderr);
132 return pthread_mutex_unlock_p(__mutex);
135 int real_pthread_create (pthread_t *__restrict __newthread, const pthread_attr_t *__restrict __attr, void *(*__start_routine)(void *), void *__restrict __arg) {
136 static int (*pthread_create_p) (pthread_t *__restrict, const pthread_attr_t *__restrict, void *(*)(void *), void * __restrict) = NULL;
138 if (!pthread_create_p) {
139 pthread_create_p = (int (*)(pthread_t *__restrict, const pthread_attr_t *__restrict, void *(*)(void *), void *__restrict))dlsym(RTLD_NEXT, "pthread_create");
140 if ((error = dlerror()) != NULL) {
141 fputs(error, stderr);
145 return pthread_create_p(__newthread, __attr, __start_routine, __arg);
148 int real_pthread_join (pthread_t __th, void ** __thread_return) {
149 static int (*pthread_join_p) (pthread_t __th, void ** __thread_return) = NULL;
151 if (!pthread_join_p) {
152 pthread_join_p = (int (*)(pthread_t __th, void ** __thread_return))dlsym(RTLD_NEXT, "pthread_join");
153 if ((error = dlerror()) != NULL) {
154 fputs(error, stderr);
158 return pthread_join_p(__th, __thread_return);
161 void finalize_helper_thread() {
162 Thread * curr_thread = thread_current();
163 model_print("finalize_helper_thread\n");
164 real_pthread_mutex_lock(&curr_thread->mutex);
165 curr_thread->tls = (char *) get_tls_addr();
166 real_pthread_mutex_unlock(&curr_thread->mutex);
167 //Wait in the kernel until it is time for us to finish
168 real_pthread_mutex_lock(&curr_thread->mutex2);
169 real_pthread_mutex_unlock(&curr_thread->mutex2);
170 //return to helper thread function
171 setcontext(&curr_thread->context);
174 void * helper_thread(void * ptr) {
175 Thread * curr_thread = thread_current();
176 model_print("helper_thread\n");
178 //build a context for this real thread so we can take it's context
179 int ret = getcontext(&curr_thread->helpercontext);
182 /* Initialize new managed context */
183 void *helperstack = stack_allocate(STACK_SIZE);
184 curr_thread->helpercontext.uc_stack.ss_sp = helperstack;
185 curr_thread->helpercontext.uc_stack.ss_size = STACK_SIZE;
186 curr_thread->helpercontext.uc_stack.ss_flags = 0;
187 curr_thread->helpercontext.uc_link = model->get_system_context();
188 makecontext(&curr_thread->helpercontext, finalize_helper_thread, 0);
190 model_swapcontext(&curr_thread->context, &curr_thread->helpercontext);
192 //start the real thread
195 //now the real thread has control again
196 stack_free(helperstack);
201 void setup_context() {
202 Thread * curr_thread = thread_current();
203 model_print("setup_context\n");
205 /* Add dummy "start" action, just to create a first clock vector */
206 model->switch_to_master(new ModelAction(THREAD_START, std::memory_order_seq_cst, curr_thread));
208 /* Initialize our lock */
209 real_pthread_mutex_init(&curr_thread->mutex, NULL);
210 real_pthread_mutex_init(&curr_thread->mutex2, NULL);
211 real_pthread_mutex_lock(&curr_thread->mutex2);
213 /* Create the real thread */
214 real_pthread_create(&curr_thread->thread, NULL, helper_thread, NULL);
215 model_print("thread_created\n");
218 real_pthread_mutex_lock(&curr_thread->mutex);
219 if (curr_thread->tls != NULL)
221 real_pthread_mutex_unlock(&curr_thread->mutex);
224 set_tls_addr((uintptr_t)curr_thread->tls);
225 model_print("tls taken\n");
226 setcontext(&curr_thread->context);
231 * Create a thread context for a new thread so we can use
232 * setcontext/getcontext/swapcontext to swap it out.
233 * @return 0 on success; otherwise, non-zero error condition
235 int Thread::create_context()
239 ret = getcontext(&context);
243 /* Initialize new managed context */
244 stack = stack_allocate(STACK_SIZE);
245 context.uc_stack.ss_sp = stack;
246 context.uc_stack.ss_size = STACK_SIZE;
247 context.uc_stack.ss_flags = 0;
248 context.uc_link = model->get_system_context();
251 makecontext(&context, setup_context, 0);
253 makecontext(&context, thread_startup, 0);
255 makecontext(&context, thread_startup, 0);
262 * Swaps the current context to another thread of execution. This form switches
263 * from a user Thread to a system context.
264 * @param t Thread representing the currently-running thread. The current
265 * context is saved here.
266 * @param ctxt Context to which we will swap. Must hold a valid system context.
267 * @return Does not return, unless we return to Thread t's context. See
268 * swapcontext(3) (returns 0 for success, -1 for failure).
270 int Thread::swap(Thread *t, ucontext_t *ctxt)
272 t->set_state(THREAD_READY);
274 set_tls_addr((uintptr_t)model->getInitThread()->tls);
276 return model_swapcontext(&t->context, ctxt);
280 * Swaps the current context to another thread of execution. This form switches
281 * from a system context to a user Thread.
282 * @param ctxt System context variable to which to save the current context.
283 * @param t Thread to which we will swap. Must hold a valid user context.
284 * @return Does not return, unless we return to the system context (ctxt). See
285 * swapcontext(3) (returns 0 for success, -1 for failure).
287 int Thread::swap(ucontext_t *ctxt, Thread *t)
289 t->set_state(THREAD_RUNNING);
292 set_tls_addr((uintptr_t)t->tls);
294 return model_swapcontext(ctxt, &t->context);
298 /** Terminate a thread and free its stack. */
299 void Thread::complete()
301 ASSERT(!is_complete());
302 DEBUG("completed thread %d\n", id_to_int(get_id()));
303 state = THREAD_COMPLETED;
307 if (this != model->getInitThread()) {
309 real_pthread_mutex_unlock(&mutex2);
310 real_pthread_join(thread, NULL);
317 * @brief Construct a new model-checker Thread
319 * A model-checker Thread is used for accounting purposes only. It will never
320 * have its own stack, and it should never be inserted into the Scheduler.
322 * @param tid The thread ID to assign
324 Thread::Thread(thread_id_t tid) :
336 state(THREAD_READY), /* Thread is always ready? */
340 memset(&context, 0, sizeof(context));
344 * Construct a new thread.
345 * @param t The thread identifier of the newly created thread.
346 * @param func The function that the thread will call.
347 * @param a The parameter to pass to this function.
349 Thread::Thread(thread_id_t tid, thrd_t *t, void (*func)(void *), void *a, Thread *parent) :
354 pstart_routine(NULL),
361 state(THREAD_CREATED),
362 last_action_val(VALUE_NONE),
367 /* Initialize state */
368 ret = create_context();
370 model_print("Error in create_context\n");
372 user_thread->priv = this; // WL
376 * Construct a new thread for pthread.
377 * @param t The thread identifier of the newly created thread.
378 * @param func The function that the thread will call.
379 * @param a The parameter to pass to this function.
381 Thread::Thread(thread_id_t tid, thrd_t *t, void *(*func)(void *), void *a, Thread *parent) :
386 pstart_routine(func),
393 state(THREAD_CREATED),
394 last_action_val(VALUE_NONE),
399 /* Initialize state */
400 ret = create_context();
402 model_print("Error in create_context\n");
413 /** @return The thread_id_t corresponding to this Thread object. */
414 thread_id_t Thread::get_id() const
420 * Set a thread's THREAD_* state (@see thread_state)
421 * @param s The state to enter
423 void Thread::set_state(thread_state s)
425 ASSERT(s == THREAD_COMPLETED || state != THREAD_COMPLETED);
430 * Get the Thread that this Thread is immediately waiting on
431 * @return The thread we are waiting on, if any; otherwise NULL
433 Thread * Thread::waiting_on() const
438 if (pending->get_type() == THREAD_JOIN)
439 return pending->get_thread_operand();
440 else if (pending->get_type() == PTHREAD_JOIN)
441 return pending->get_thread_operand();
442 else if (pending->is_lock())
443 return (Thread *)pending->get_mutex()->get_state()->locked;
448 * Check if this Thread is waiting (blocking) on a given Thread, directly or
449 * indirectly (via a chain of waiting threads)
451 * @param t The Thread on which we may be waiting
452 * @return True if we are waiting on Thread t; false otherwise
454 bool Thread::is_waiting_on(const Thread *t) const
457 for (wait = waiting_on();wait != NULL;wait = wait->waiting_on())