/* * RT-Mutex-tester: scriptable tester for rt mutexes * * started by Thomas Gleixner: * *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com> * */#include <linux/device.h>#include <linux/kthread.h>#include <linux/export.h>#include <linux/sched.h>#include <linux/sched/rt.h>#include <linux/spinlock.h>#include <linux/timer.h>#include <linux/freezer.h> #include "rtmutex.h" #define MAX_RT_TEST_THREADS	8#define MAX_RT_TEST_MUTEXES	8 static spinlock_t rttest_lock;static atomic_t rttest_event; struct test_thread_data {	int			opcode;	int			opdata;	int			mutexes[MAX_RT_TEST_MUTEXES];	int			event;	struct device		dev;}; static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];static struct task_struct *threads[MAX_RT_TEST_THREADS];static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES]; enum test_opcodes {	RTTEST_NOP = 0,	RTTEST_SCHEDOT,		/* 1 Sched other, data = nice */	RTTEST_SCHEDRT,		/* 2 Sched fifo, data = prio */	RTTEST_LOCK,		/* 3 Lock uninterruptible, data = lockindex */	RTTEST_LOCKNOWAIT,	/* 4 Lock uninterruptible no wait in wakeup, data = lockindex */	RTTEST_LOCKINT,		/* 5 Lock interruptible, data = lockindex */	RTTEST_LOCKINTNOWAIT,	/* 6 Lock interruptible no wait in wakeup, data = lockindex */	RTTEST_LOCKCONT,	/* 7 Continue locking after the wakeup delay */	RTTEST_UNLOCK,		/* 8 Unlock, data = lockindex */	/* 9, 10 - reserved for BKL commemoration */	RTTEST_SIGNAL = 11,	/* 11 Signal other test thread, data = thread id */	RTTEST_RESETEVENT = 98,	/* 98 Reset event counter */	RTTEST_RESET = 99,	/* 99 Reset all pending operations */}; static int handle_op(struct test_thread_data *td, int lockwakeup){	int i, id, ret = -EINVAL; 	switch(td->opcode) { 	case RTTEST_NOP:		return 0; 	case RTTEST_LOCKCONT:		td->mutexes[td->opdata] = 1;		td->event = atomic_add_return(1, &rttest_event);		return 0; 	case RTTEST_RESET:		for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {			if (td->mutexes[i] == 4) {				rt_mutex_unlock(&mutexes[i]);				td->mutexes[i] = 0;			}		}		return 0; 	case RTTEST_RESETEVENT:		atomic_set(&rttest_event, 0);		return 0; 	default:		if (lockwakeup)			return ret;	} 	switch(td->opcode) { 	case RTTEST_LOCK:	case RTTEST_LOCKNOWAIT:		id = td->opdata;		if (id < 0 || id >= MAX_RT_TEST_MUTEXES)			return ret; 		td->mutexes[id] = 1;		td->event = atomic_add_return(1, &rttest_event);		rt_mutex_lock(&mutexes[id]);		td->event = atomic_add_return(1, &rttest_event);		td->mutexes[id] = 4;		return 0; 	case RTTEST_LOCKINT:	case RTTEST_LOCKINTNOWAIT:		id = td->opdata;		if (id < 0 || id >= MAX_RT_TEST_MUTEXES)			return ret; 		td->mutexes[id] = 1;		td->event = atomic_add_return(1, &rttest_event);		ret = rt_mutex_lock_interruptible(&mutexes[id], 0);		td->event = atomic_add_return(1, &rttest_event);		td->mutexes[id] = ret ? 0 : 4;		return ret ? -EINTR : 0; 	case RTTEST_UNLOCK:		id = td->opdata;		if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)			return ret; 		td->event = atomic_add_return(1, &rttest_event);		rt_mutex_unlock(&mutexes[id]);		td->event = atomic_add_return(1, &rttest_event);		td->mutexes[id] = 0;		return 0; 	default:		break;	}	return ret;} /* * Schedule replacement for rtsem_down(). Only called for threads with * PF_MUTEX_TESTER set. * * This allows us to have finegrained control over the event flow. * */void schedule_rt_mutex_test(struct rt_mutex *mutex){	int tid, op, dat;	struct test_thread_data *td; 	/* We have to lookup the task */	for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {		if (threads[tid] == current)			break;	} 	BUG_ON(tid == MAX_RT_TEST_THREADS); 	td = &thread_data[tid]; 	op = td->opcode;	dat = td->opdata; 	switch (op) {	case RTTEST_LOCK:	case RTTEST_LOCKINT:	case RTTEST_LOCKNOWAIT:	case RTTEST_LOCKINTNOWAIT:		if (mutex != &mutexes[dat])			break; 		if (td->mutexes[dat] != 1)			break; 		td->mutexes[dat] = 2;		td->event = atomic_add_return(1, &rttest_event);		break; 	default:		break;	} 	schedule();  	switch (op) {	case RTTEST_LOCK:	case RTTEST_LOCKINT:		if (mutex != &mutexes[dat])			return; 		if (td->mutexes[dat] != 2)			return; 		td->mutexes[dat] = 3;		td->event = atomic_add_return(1, &rttest_event);		break; 	case RTTEST_LOCKNOWAIT:	case RTTEST_LOCKINTNOWAIT:		if (mutex != &mutexes[dat])			return; 		if (td->mutexes[dat] != 2)			return; 		td->mutexes[dat] = 1;		td->event = atomic_add_return(1, &rttest_event);		return; 	default:		return;	} 	td->opcode = 0; 	for (;;) {		set_current_state(TASK_INTERRUPTIBLE); 		if (td->opcode > 0) {			int ret; 			set_current_state(TASK_RUNNING);			ret = handle_op(td, 1);			set_current_state(TASK_INTERRUPTIBLE);			if (td->opcode == RTTEST_LOCKCONT)				break;			td->opcode = ret;		} 		/* Wait for the next command to be executed */		schedule();	} 	/* Restore previous command and data */	td->opcode = op;	td->opdata = dat;} static int test_func(void *data){	struct test_thread_data *td = data;	int ret; 	current->flags |= PF_MUTEX_TESTER;	set_freezable();	allow_signal(SIGHUP); 	for(;;) { 		set_current_state(TASK_INTERRUPTIBLE); 		if (td->opcode > 0) {			set_current_state(TASK_RUNNING);			ret = handle_op(td, 0);			set_current_state(TASK_INTERRUPTIBLE);			td->opcode = ret;		} 		/* Wait for the next command to be executed */		schedule();		try_to_freeze(); 		if (signal_pending(current))			flush_signals(current); 		if(kthread_should_stop())			break;	}	return 0;} /** * sysfs_test_command - interface for test commands * @dev:	thread reference * @buf:	command for actual step * @count:	length of buffer * * command syntax: * * opcode:data */static ssize_t sysfs_test_command(struct device *dev, struct device_attribute *attr,				  const char *buf, size_t count){	struct sched_param schedpar;	struct test_thread_data *td;	char cmdbuf[32];	int op, dat, tid, ret; 	td = container_of(dev, struct test_thread_data, dev);	tid = td->dev.id; 	/* strings from sysfs write are not 0 terminated! */	if (count >= sizeof(cmdbuf))		return -EINVAL; 	/* strip of \n: */	if (buf[count-1] == '\n')		count--;	if (count < 1)		return -EINVAL; 	memcpy(cmdbuf, buf, count);	cmdbuf[count] = 0; 	if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)		return -EINVAL; 	switch (op) {	case RTTEST_SCHEDOT:		schedpar.sched_priority = 0;		ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);		if (ret)			return ret;		set_user_nice(current, 0);		break; 	case RTTEST_SCHEDRT:		schedpar.sched_priority = dat;		ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);		if (ret)			return ret;		break; 	case RTTEST_SIGNAL:		send_sig(SIGHUP, threads[tid], 0);		break; 	default:		if (td->opcode > 0)			return -EBUSY;		td->opdata = dat;		td->opcode = op;		wake_up_process(threads[tid]);	} 	return count;} /** * sysfs_test_status - sysfs interface for rt tester * @dev:	thread to query * @buf:	char buffer to be filled with thread status info */static ssize_t sysfs_test_status(struct device *dev, struct device_attribute *attr,				 char *buf){	struct test_thread_data *td;	struct task_struct *tsk;	char *curr = buf;	int i; 	td = container_of(dev, struct test_thread_data, dev);	tsk = threads[td->dev.id]; 	spin_lock(&rttest_lock); 	curr += sprintf(curr,		"O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, M:",		td->opcode, td->event, tsk->state,			(MAX_RT_PRIO - 1) - tsk->prio,			(MAX_RT_PRIO - 1) - tsk->normal_prio,		tsk->pi_blocked_on); 	for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)		curr += sprintf(curr, "%d", td->mutexes[i]); 	spin_unlock(&rttest_lock); 	curr += sprintf(curr, ", T: %p, R: %p\n", tsk,			mutexes[td->dev.id].owner); 	return curr - buf;} static DEVICE_ATTR(status, 0600, sysfs_test_status, NULL);static DEVICE_ATTR(command, 0600, NULL, sysfs_test_command); static struct bus_type rttest_subsys = {	.name = "rttest",	.dev_name = "rttest",}; static int init_test_thread(int id){	thread_data[id].dev.bus = &rttest_subsys;	thread_data[id].dev.id = id; 	threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);	if (IS_ERR(threads[id]))		return PTR_ERR(threads[id]); 	return device_register(&thread_data[id].dev);} static int init_rttest(void){	int ret, i; 	spin_lock_init(&rttest_lock); 	for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)		rt_mutex_init(&mutexes[i]); 	ret = subsys_system_register(&rttest_subsys, NULL);	if (ret)		return ret; 	for (i = 0; i < MAX_RT_TEST_THREADS; i++) {		ret = init_test_thread(i);		if (ret)			break;		ret = device_create_file(&thread_data[i].dev, &dev_attr_status);		if (ret)			break;		ret = device_create_file(&thread_data[i].dev, &dev_attr_command);		if (ret)			break;	} 	printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" ); 	return ret;} device_initcall(init_rttest);