2 * @brief Thread functions.
5 #include "libthreads.h"
9 /* global "model" object */
12 /** Allocate a stack for a new thread. */
13 static void * stack_allocate(size_t size)
18 /** Free a stack for a terminated thread. */
19 static void stack_free(void *stack)
24 /** Return the currently executing thread. */
25 Thread * thread_current(void)
28 return model->get_current_thread();
32 * Provides a startup wrapper for each thread, allowing some initial
33 * model-checking data to be recorded. This method also gets around makecontext
34 * not being 64-bit clean
35 * @todo We should make the START event always immediately follow the
36 * CREATE event, so we don't get redundant traces...
40 Thread * curr_thread = thread_current();
42 /* Add dummy "start" action, just to create a first clock vector */
43 model->switch_to_master(new ModelAction(THREAD_START, std::memory_order_seq_cst, curr_thread));
45 /* Call the actual thread function */
46 curr_thread->start_routine(curr_thread->arg);
50 * Create a thread context for a new thread so we can use
51 * setcontext/getcontext/swapcontext to swap it out.
52 * @return 0 on success; otherwise, non-zero error condition
54 int Thread::create_context()
58 ret = getcontext(&context);
62 /* Initialize new managed context */
63 stack = stack_allocate(STACK_SIZE);
64 context.uc_stack.ss_sp = stack;
65 context.uc_stack.ss_size = STACK_SIZE;
66 context.uc_stack.ss_flags = 0;
67 context.uc_link = model->get_system_context();
68 makecontext(&context, thread_startup, 0);
74 * Swaps the current context to another thread of execution. This form switches
75 * from a user Thread to a system context.
76 * @param t Thread representing the currently-running thread. The current
77 * context is saved here.
78 * @param ctxt Context to which we will swap. Must hold a valid system context.
79 * @return Does not return, unless we return to Thread t's context. See
80 * swapcontext(3) (returns 0 for success, -1 for failure).
82 int Thread::swap(Thread *t, ucontext_t *ctxt)
84 return swapcontext(&t->context, ctxt);
88 * Swaps the current context to another thread of execution. This form switches
89 * from a system context to a user Thread.
90 * @param ctxt System context variable to which to save the current context.
91 * @param t Thread to which we will swap. Must hold a valid user context.
92 * @return Does not return, unless we return to the system context (ctxt). See
93 * swapcontext(3) (returns 0 for success, -1 for failure).
95 int Thread::swap(ucontext_t *ctxt, Thread *t)
97 return swapcontext(ctxt, &t->context);
101 /** Terminate a thread and free its stack. */
102 void Thread::complete()
104 if (state != THREAD_COMPLETED) {
105 DEBUG("completed thread %d\n", get_id());
106 state = THREAD_COMPLETED;
113 * Construct a new thread.
114 * @param t The thread identifier of the newly created thread.
115 * @param func The function that the thread will call.
116 * @param a The parameter to pass to this function.
118 Thread::Thread(thrd_t *t, void (*func)(void *), void *a) :
122 state(THREAD_CREATED),
123 last_action_val(VALUE_NONE)
127 /* Initialize state */
128 ret = create_context();
130 printf("Error in create_context\n");
132 id = model->get_next_id();
134 parent = thread_current();
141 model->remove_thread(this);
144 /** @return The thread_id_t corresponding to this Thread object. */
145 thread_id_t Thread::get_id()