153 lines
3.8 KiB
C++
153 lines
3.8 KiB
C++
/*
|
|
* \brief Implementation of the Thread API via Linux threads
|
|
* \author Norman Feske
|
|
* \author Martin Stein
|
|
* \date 2006-06-13
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2006-2013 Genode Labs GmbH
|
|
*
|
|
* This file is part of the Genode OS framework, which is distributed
|
|
* under the terms of the GNU General Public License version 2.
|
|
*/
|
|
|
|
/* Genode includes */
|
|
#include <base/env.h>
|
|
#include <base/thread.h>
|
|
#include <base/snprintf.h>
|
|
#include <base/sleep.h>
|
|
#include <linux_cpu_session/linux_cpu_session.h>
|
|
|
|
/* base-internal includes */
|
|
#include <base/internal/stack.h>
|
|
|
|
/* Linux syscall bindings */
|
|
#include <linux_syscalls.h>
|
|
|
|
using namespace Genode;
|
|
|
|
extern int main_thread_futex_counter;
|
|
|
|
static void empty_signal_handler(int) { }
|
|
|
|
|
|
static Lock &startup_lock()
|
|
{
|
|
static Lock lock(Lock::LOCKED);
|
|
return lock;
|
|
}
|
|
|
|
|
|
/**
|
|
* Signal handler for killing the thread
|
|
*/
|
|
static void thread_exit_signal_handler(int) { lx_exit(0); }
|
|
|
|
|
|
void Thread_base::_thread_start()
|
|
{
|
|
/*
|
|
* Set signal handler such that canceled system calls get not
|
|
* transparently retried after a signal gets received.
|
|
*/
|
|
lx_sigaction(LX_SIGUSR1, empty_signal_handler);
|
|
|
|
Thread_base * const thread = Thread_base::myself();
|
|
|
|
/* inform core about the new thread and process ID of the new thread */
|
|
Linux_cpu_session *cpu = dynamic_cast<Linux_cpu_session *>(thread->_cpu_session);
|
|
if (cpu)
|
|
cpu->thread_id(thread->cap(), thread->tid().pid, thread->tid().tid);
|
|
|
|
/* wakeup 'start' function */
|
|
startup_lock().unlock();
|
|
|
|
thread->entry();
|
|
|
|
/* unblock caller of 'join()' */
|
|
thread->_join_lock.unlock();
|
|
|
|
sleep_forever();
|
|
}
|
|
|
|
|
|
void Thread_base::_init_platform_thread(size_t weight, Type type)
|
|
{
|
|
/* if no cpu session is given, use it from the environment */
|
|
if (!_cpu_session)
|
|
_cpu_session = env()->cpu_session();
|
|
|
|
/* for normal threads create an object at the CPU session */
|
|
if (type == NORMAL) {
|
|
_thread_cap = _cpu_session->create_thread(weight, _stack->name().string());
|
|
return;
|
|
}
|
|
/* adjust initial object state for main threads */
|
|
tid().futex_counter = main_thread_futex_counter;
|
|
_thread_cap = env()->parent()->main_thread_cap();
|
|
}
|
|
|
|
|
|
void Thread_base::_deinit_platform_thread()
|
|
{
|
|
/*
|
|
* Kill thread until it is really really dead
|
|
*
|
|
* We use the 'tgkill' system call to kill the thread. This system call
|
|
* returns immediately and just flags the corresponding signal at the
|
|
* targeted thread context. However, the thread still lives until the
|
|
* signal flags are evaluated. When leaving this function, however, we want
|
|
* to be sure that the thread is no more executing any code such that we
|
|
* an safely free and unmap the thread's stack. So we call 'tgkill' in a
|
|
* loop until we get an error indicating that the thread does not exists
|
|
* anymore.
|
|
*/
|
|
for (;;) {
|
|
|
|
/* destroy thread locally */
|
|
int ret = lx_tgkill(_tid.pid, _tid.tid, LX_SIGCANCEL);
|
|
|
|
if (ret < 0) break;
|
|
|
|
/* if thread still exists, wait a bit and try to kill it again */
|
|
struct timespec ts = { 0, 500 };
|
|
lx_nanosleep(&ts, 0);
|
|
}
|
|
|
|
/* inform core about the killed thread */
|
|
_cpu_session->kill_thread(_thread_cap);
|
|
}
|
|
|
|
|
|
void Thread_base::start()
|
|
{
|
|
/* synchronize calls of the 'start' function */
|
|
static Lock lock;
|
|
Lock::Guard guard(lock);
|
|
|
|
/*
|
|
* The first time we enter this code path, the 'start' function is
|
|
* called by the main thread as there cannot exist other threads
|
|
* without executing this function. When first called, we initialize
|
|
* the thread lib here.
|
|
*/
|
|
static bool threadlib_initialized = false;
|
|
if (!threadlib_initialized) {
|
|
lx_sigaction(LX_SIGCANCEL, thread_exit_signal_handler);
|
|
threadlib_initialized = true;
|
|
}
|
|
|
|
_tid.tid = lx_create_thread(Thread_base::_thread_start, stack_top(), this);
|
|
_tid.pid = lx_getpid();
|
|
|
|
/* wait until the 'thread_start' function got entered */
|
|
startup_lock().lock();
|
|
}
|
|
|
|
|
|
void Thread_base::cancel_blocking()
|
|
{
|
|
_cpu_session->cancel_blocking(_thread_cap);
|
|
}
|