rt-thread/libcpu/sim/posix/cpu_port.c

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/*
* author : prife (goprife@gmail.com)
* date : 2013/01/14 01:18:50
* version: v 0.2.0
*/
#include <rtthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <signal.h>
#include <unistd.h>
#include <semaphore.h>
#include <time.h>
#include <sys/time.h>
//#define TRACE printf
#define TRACE(...)
typedef struct _thread
{
pthread_t pthread;
void (*task)(void *);
void *para;
void (*exit)(void);
sem_t sem;
rt_thread_t rtthread;
int status;
void *data;
} thread_t;
#define THREAD_T(thread) ((thread_t *)thread)
#define MSG_SUSPEND SIGUSR1 /* 10 */
#define MSG_RESUME SIGUSR2
#define MSG_TICK SIGALRM /* 14 */
#define TIMER_TYPE ITIMER_REAL
#define MAX_INTERRUPT_NUM ((unsigned int)sizeof(unsigned int) * 8)
#define INTERRUPT_ENABLE 0
#define INTERRUPT_DISABLE 1
/* 线程挂起状态,共两种取值 */
#define SUSPEND_LOCK 0
#define SUSPEND_SIGWAIT 1
#define THREAD_RUNNING 2
/* interrupt flag, if 1, disable, if 0, enable */
static long interrupt_disable_flag;
//static int systick_signal_flag;
/* flag in interrupt handling */
rt_uint32_t rt_interrupt_from_thread, rt_interrupt_to_thread;
rt_uint32_t rt_thread_switch_interrupt_flag;
/* interrupt event mutex */
static pthread_mutex_t *ptr_int_mutex;
static pthread_cond_t cond_int_hit; /* interrupt occured! */
static volatile unsigned int cpu_pending_interrupts;
static int (* cpu_isr_table[MAX_INTERRUPT_NUM])(void) = {0};
static pthread_t mainthread_pid;
/* function definition */
static void start_sys_timer(void);
static int tick_interrupt_isr(void);
static void mthread_signal_tick(int sig);
static int mainthread_scheduler(void);
int signal_install(int sig, void (*func)(int))
{
struct sigaction act;
/* set the signal handler */
act.sa_handler = func ;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
sigaction(sig, &act, 0);
}
int signal_mask(void)
{
sigset_t sigmask, oldmask;
/* set signal mask */
sigemptyset(&sigmask);
sigaddset(&sigmask, SIGALRM);
pthread_sigmask(SIG_BLOCK, &sigmask, &oldmask);
}
static void thread_suspend_signal_handler(int sig)
{
sigset_t sigmask;
pthread_t pid = pthread_self();
thread_t *thread_from;
thread_t *thread_to;
rt_thread_t tid;
if (sig != MSG_SUSPEND)
{
printf("get an unexpected signal <%d>, exit\n", sig);
exit(EXIT_FAILURE);
}
thread_from = (thread_t *) rt_interrupt_from_thread;
thread_to = (thread_t *) rt_interrupt_to_thread;
/* 注意!此时 rt_thread_self的值是to线程的值 */
tid = rt_thread_self();
/* FIXME RT_ASSERT(thread_from->pthread == pid); */
RT_ASSERT((thread_t *)(tid->sp) == thread_to);
TRACE("signal: SIGSUSPEND suspend <%s>\n", thread_from->rtthread->name);
/* 使用sigwait或者sigsuspend来挂起from线程 */
//sem_wait(&thread_from->sem);
sigemptyset(&sigmask);
sigaddset(&sigmask, MSG_RESUME);
/* Beginnig Linux Programming上说当信号处理函数运行中此信号就会被屏蔽
* 以防止重复执行信号处理函数
*/
thread_from->status = SUSPEND_SIGWAIT;
if (sigwait(&sigmask, &sig) != 0)
{
printf("sigwait faild, %d\n", sig);
}
thread_to = (thread_t *) rt_interrupt_to_thread;
RT_ASSERT(thread_to == thread_from);
thread_to->status = THREAD_RUNNING;
TRACE("signal: SIGSUSPEND resume <%s>\n", thread_from->rtthread->name);
}
static void thread_resume_signal_handler(int sig)
{
sigset_t sigmask;
pthread_t pid = pthread_self();
thread_t *thread_from;
thread_t *thread_to;
rt_thread_t tid;
thread_from = (thread_t *) rt_interrupt_from_thread;
thread_to = (thread_t *) rt_interrupt_to_thread;
/* 注意!此时 rt_thread_self的值是to线程的值 */
tid = rt_thread_self();
RT_ASSERT((thread_t *)(tid->sp) == thread_to);
TRACE("signal: SIGRESUME resume <%s>\n", thread_to->rtthread->name);
}
static void *thread_run(void *parameter)
{
rt_thread_t tid;
thread_t *thread;
thread = THREAD_T(parameter);
int res;
/* set signal mask, mask the timer! */
signal_mask();
thread->status = SUSPEND_LOCK;
TRACE("pid <%08x> stop on sem...\n", (unsigned int)(thread->pthread));
sem_wait(&thread->sem);
tid = rt_thread_self();
TRACE("pid <%08x> tid <%s> starts...\n", (unsigned int)(thread->pthread),
tid->name);
thread->rtthread = tid;
thread->task(thread->para);
TRACE("pid <%08x> tid <%s> exit...\n", (unsigned int)(thread->pthread),
tid->name);
thread->exit();
/*TODO:
* 最后一行的pthread_exit永远没有机会执行这是因为在threead->exit函数中
* 会发生线程切换并永久将此pthread线程挂起所以更完美的解决方案是在这
* 里发送信号给主线程,主线程中再次唤醒此线程令其自动退出。
*/
//sem_destroy(&thread->sem);
pthread_exit(NULL);
}
static int thread_create(
thread_t *thread, void *task, void *parameter, void *pexit)
{
int res;
pthread_attr_t attr;
thread->task = task;
thread->para = parameter;
thread->exit = pexit;
if (sem_init(&thread->sem, 0, 0) != 0)
{
printf("init thread->sem failed, exit \n");
exit(EXIT_FAILURE);
}
/* No need to join the threads. */
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
/* create a posix thread */
res = pthread_create(&thread->pthread, &attr, &thread_run, (void *)thread);
if (res)
{
printf("pthread create faild, <%d>\n", res);
exit(EXIT_FAILURE);
}
return 0;
}
/* resume the thread */
static int thread_resume(thread_t *thread)
{
sem_post(& thread->sem);
}
rt_uint8_t *rt_hw_stack_init(
void *pEntry,
void *pParam,
rt_uint8_t *pStackAddr,
void *pExit)
{
thread_t *thread;
thread = (thread_t *)(pStackAddr - sizeof(thread_t));
/* set the filed to zero */
memset(thread, 0x00, sizeof(thread_t));
thread_create(thread, pEntry, pParam, pExit);
//TRACE("thread %x created\n", (unsigned int)thread_table[t].pthread);
return (rt_uint8_t *) thread;
}
rt_base_t rt_hw_interrupt_disable(void)
{
long back;
if (ptr_int_mutex == NULL)
{
return 0;
}
pthread_mutex_lock(ptr_int_mutex);
back = interrupt_disable_flag;
interrupt_disable_flag = INTERRUPT_DISABLE;
/*TODO: It may need to unmask the signal */
return back;
}
void rt_hw_interrupt_enable(rt_base_t level)
{
struct rt_thread * tid;
pthread_t pid;
thread_t *thread_from;
thread_t *thread_to;
if (ptr_int_mutex == NULL)
return;
interrupt_disable_flag = level;
pthread_mutex_unlock(ptr_int_mutex);
/* 如果已经中断仍然关闭 */
if (interrupt_disable_flag)
{
return;
}
/* 表示当前中断打开, 检查是否有挂起的中断 */
pthread_mutex_lock(ptr_int_mutex);
if (!cpu_pending_interrupts)
{
pthread_mutex_unlock(ptr_int_mutex);
return;
}
thread_from = (thread_t *) rt_interrupt_from_thread;
thread_to = (thread_t *) rt_interrupt_to_thread;
tid = rt_thread_self();
pid = pthread_self();
//pid != mainthread_pid &&
if (thread_from->pthread == pid)
{
/* 注意这段代码是在RTT普通线程函数总函数中执行的
* from线程就是当前rtt线程 */
/* 需要检查是否有挂起的中断需要处理 */
TRACE("conswitch: P in pid<%x> ,suspend <%s>, resume <%s>!\n",
(unsigned int)pid,
thread_from->rtthread->name,
thread_to->rtthread->name);
cpu_pending_interrupts --;
thread_from->status = SUSPEND_LOCK;
pthread_mutex_unlock(ptr_int_mutex);
/* 唤醒被挂起的线程 */
if (thread_to->status == SUSPEND_SIGWAIT)
{
pthread_kill(thread_to->pthread, MSG_RESUME);
}
else if (thread_to->status == SUSPEND_LOCK)
{
sem_post(& thread_to->sem);
}
else
{
printf("conswitch: should not be here! %d\n", __LINE__);
exit(EXIT_FAILURE);
}
/* 挂起当前的线程 */
sem_wait(& thread_from->sem);
pthread_mutex_lock(ptr_int_mutex);
thread_from->status = THREAD_RUNNING;
pthread_mutex_unlock(ptr_int_mutex);
}
else
{
/* 注意这段代码可能在多种情况下运行:
* 1. 在system tick中执行 即主线程的SIGALRM信号处理函数中执行
* 2. 其他线程中调用,比如用于获取按键输入的线程中调用
*/
TRACE("conswitch: S in pid<%x> ,suspend <%s>, resume <%s>!\n",
(unsigned int)pid,
thread_from->rtthread->name,
thread_to->rtthread->name);
cpu_pending_interrupts --;
/* 需要把解锁函数放在前面,以防止死锁?? */
pthread_mutex_unlock(ptr_int_mutex);
/* 挂起from线程 */
pthread_kill(thread_from->pthread, MSG_SUSPEND);
/* 注意:这里需要确保线程被挂起了, 否则312行就很可能就会报错退出
* 因为这里挂起线程是通过信号实现的,所以一定要确保线程挂起才行 */
while (thread_from->status != SUSPEND_SIGWAIT)
{
sched_yield();
}
/* 唤醒to线程 */
if (thread_to->status == SUSPEND_SIGWAIT)
{
pthread_kill(thread_to->pthread, MSG_RESUME);
}
else if (thread_to->status == SUSPEND_LOCK)
{
sem_post(& thread_to->sem);
}
else
{
printf("conswitch: should not be here! %d\n", __LINE__);
exit(EXIT_FAILURE);
}
}
/*TODO: It may need to unmask the signal */
}
void rt_hw_context_switch(rt_uint32_t from,
rt_uint32_t to)
{
struct rt_thread * tid;
pthread_t pid;
thread_t *thread_from;
thread_t *thread_to;
RT_ASSERT(from != to);
#if 0
//TODO: 可能还需要考虑嵌套切换的情况
if (rt_thread_switch_interrupt_flag != 1)
{
rt_thread_switch_interrupt_flag = 1;
// set rt_interrupt_from_thread
rt_interrupt_from_thread = *((rt_uint32_t *)from);
}
#endif
pthread_mutex_lock(ptr_int_mutex);
rt_interrupt_from_thread = *((rt_uint32_t *)from);
rt_interrupt_to_thread = *((rt_uint32_t *)to);
/* 这个函数只是并不会真正执行中断处理函数,而只是简单的
* 设置一下中断挂起标志位
*/
cpu_pending_interrupts ++;
pthread_mutex_unlock(ptr_int_mutex);
}
void rt_hw_context_switch_interrupt(rt_uint32_t from,
rt_uint32_t to)
{
rt_hw_context_switch(from, to);
}
void rt_hw_context_switch_to(rt_uint32_t to)
{
//set to thread
rt_interrupt_to_thread = *((rt_uint32_t *)(to));
//clear from thread
rt_interrupt_from_thread = 0;
//set interrupt to 1
rt_thread_switch_interrupt_flag = 0; //TODO: 还需要考虑这个嵌套切换的情况
/* enable interrupt
* note: NOW, there are only one interrupt in simposix: system tick */
rt_hw_interrupt_enable(0);
//start the main thread scheduler
mainthread_scheduler();
//never reach here!
return;
}
static int mainthread_scheduler(void)
{
int i, res, sig;
thread_t *thread_from;
thread_t *thread_to;
pthread_mutex_t mutex;
pthread_mutexattr_t mutexattr;
sigset_t sigmask, oldmask;
/* save the main thread id */
mainthread_pid = pthread_self();
TRACE("pid <%08x> mainthread\n", (unsigned int)(mainthread_pid));
/* 屏蔽suspend信号和resume信号 */
sigemptyset(&sigmask);
sigaddset(&sigmask, MSG_SUSPEND);
sigaddset(&sigmask, MSG_RESUME);
pthread_sigmask(SIG_BLOCK, &sigmask, &oldmask);
sigemptyset(&sigmask);
sigaddset(&sigmask, SIGALRM);
/* install signal handler of system tick */
signal_install(SIGALRM, mthread_signal_tick);
/* install signal handler used to suspend/resume threads */
signal_install(MSG_SUSPEND, thread_suspend_signal_handler);
signal_install(MSG_RESUME, thread_resume_signal_handler);
/* create a mutex and condition val, used to indicate interrupts occrue */
ptr_int_mutex = &mutex;
pthread_mutexattr_init(&mutexattr);
pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_RECURSIVE_NP);
pthread_mutex_init(ptr_int_mutex, &mutexattr);
/* start timer */
start_sys_timer();
thread_to = (thread_t *) rt_interrupt_to_thread;
thread_resume(thread_to);
for (;;)
{
#if 1
if (sigwait(&sigmask, &sig) != 0)
{
printf("mthread: sigwait get unexpected sig %d\n", sig);
}
#else
pause();
#endif
TRACE("mthread:got sig %d\n", sig);
/* signal mask sigalrm 屏蔽SIGALRM信号 */
pthread_sigmask(SIG_BLOCK, &sigmask, &oldmask);
// if (systick_signal_flag != 0)
if (pthread_mutex_trylock(ptr_int_mutex) == 0)
{
tick_interrupt_isr();
// systick_signal_flag = 0;
pthread_mutex_unlock(ptr_int_mutex);
}
else
{
TRACE("try lock failed.\n");
}
/* 开启SIGALRM信号 */
pthread_sigmask(SIG_UNBLOCK, &sigmask, &oldmask);
}
return 0;
}
/*
* Setup the systick timer to generate the tick interrupts at the required
* frequency.
*/
static void start_sys_timer(void)
{
struct itimerval itimer, oitimer;
int us;
RT_ASSERT(RT_TICK_PER_SECOND <= 1000000 || RT_TICK_PER_SECOND >= 1);
us = 1000000 / RT_TICK_PER_SECOND - 1;
TRACE("start system tick!\n");
/* Initialise the structure with the current timer information. */
if (0 != getitimer(TIMER_TYPE, &itimer))
{
TRACE("get timer failed.\n");
exit(EXIT_FAILURE);
}
/* Set the interval between timer events. */
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = us;
/* Set the current count-down. */
itimer.it_value.tv_sec = 0;
itimer.it_value.tv_usec = us;
/* Set-up the timer interrupt. */
if (0 != setitimer(TIMER_TYPE, &itimer, &oitimer))
{
TRACE("set timer failed.\n");
exit(EXIT_FAILURE);
}
}
static void mthread_signal_tick(int sig)
{
int res;
pthread_t pid = pthread_self();
if (sig == SIGALRM)
{
TRACE("pid <%x> signal: SIGALRM enter!\n", (unsigned int)pid);
//systick_signal_flag = 1;
TRACE("pid <%x> signal: SIGALRM leave!\n", (unsigned int)pid);
}
else
{
TRACE("got an unexpected signal <%d>\n", sig);
exit(EXIT_FAILURE);
}
}
/* isr return value: 1, should not be masked, if 0, can be masked */
static int tick_interrupt_isr(void)
{
TRACE("isr: systick enter!\n");
/* enter interrupt */
rt_interrupt_enter();
rt_tick_increase();
/* leave interrupt */
rt_interrupt_leave();
TRACE("isr: systick leave!\n");
return 0;
}