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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2021/01/02 bernard the first version
*/
#include <rtthread.h>
#include <lwp.h>
#ifdef ARCH_MM_MMU
#include <lwp_user_mm.h>
#endif
#include "sys/time.h"
struct rt_futex
{
int *uaddr;
rt_list_t waiting_thread;
struct lwp_avl_struct node;
struct rt_object *custom_obj;
};
static struct rt_mutex _futex_lock;
static int futex_system_init(void)
{
rt_mutex_init(&_futex_lock, "futexList", RT_IPC_FLAG_FIFO);
return 0;
}
INIT_PREV_EXPORT(futex_system_init);
rt_err_t futex_destory(void *data)
{
rt_err_t ret = -1;
rt_base_t level;
struct rt_futex *futex = (struct rt_futex *)data;
if (futex)
{
level = rt_hw_interrupt_disable();
/* remove futex from futext avl */
lwp_avl_remove(&futex->node, (struct lwp_avl_struct **)futex->node.data);
rt_hw_interrupt_enable(level);
/* release object */
rt_free(futex);
ret = 0;
}
return ret;
}
struct rt_futex *futex_create(int *uaddr, struct rt_lwp *lwp)
{
struct rt_futex *futex = RT_NULL;
struct rt_object *obj = RT_NULL;
if (!lwp)
{
return RT_NULL;
}
futex = (struct rt_futex *)rt_malloc(sizeof(struct rt_futex));
if (!futex)
{
return RT_NULL;
}
obj = rt_custom_object_create("futex", (void *)futex, futex_destory);
if (!obj)
{
rt_free(futex);
return RT_NULL;
}
futex->uaddr = uaddr;
futex->node.avl_key = (avl_key_t)uaddr;
futex->node.data = &lwp->address_search_head;
futex->custom_obj = obj;
rt_list_init(&(futex->waiting_thread));
/* insert into futex head */
lwp_avl_insert(&futex->node, &lwp->address_search_head);
return futex;
}
static struct rt_futex *futex_get(void *uaddr, struct rt_lwp *lwp)
{
struct rt_futex *futex = RT_NULL;
struct lwp_avl_struct *node = RT_NULL;
node = lwp_avl_find((avl_key_t)uaddr, lwp->address_search_head);
if (!node)
{
return RT_NULL;
}
futex = rt_container_of(node, struct rt_futex, node);
return futex;
}
int futex_wait(struct rt_futex *futex, int value, const struct timespec *timeout)
{
rt_base_t level = 0;
rt_err_t ret = -RT_EINTR;
if (*(futex->uaddr) == value)
{
rt_thread_t thread = rt_thread_self();
level = rt_hw_interrupt_disable();
ret = rt_thread_suspend_with_flag(thread, RT_INTERRUPTIBLE);
if (ret < 0)
{
rt_mutex_release(&_futex_lock);
rt_hw_interrupt_enable(level);
rt_set_errno(EINTR);
return ret;
}
/* add into waiting thread list */
rt_list_insert_before(&(futex->waiting_thread), &(thread->tlist));
/* with timeout */
if (timeout)
{
rt_int32_t time = timeout->tv_sec * RT_TICK_PER_SECOND + timeout->tv_nsec * RT_TICK_PER_SECOND / NANOSECOND_PER_SECOND;
if (time < 0)
{
time = 0;
}
/* start the timer of thread */
rt_timer_control(&(thread->thread_timer),
RT_TIMER_CTRL_SET_TIME,
&time);
rt_timer_start(&(thread->thread_timer));
}
rt_mutex_release(&_futex_lock);
rt_hw_interrupt_enable(level);
/* do schedule */
rt_schedule();
ret = thread->error;
/* check errno */
}
else
{
rt_mutex_release(&_futex_lock);
rt_set_errno(EAGAIN);
}
return ret;
}
void futex_wake(struct rt_futex *futex, int number)
{
rt_base_t level = rt_hw_interrupt_disable();
while (!rt_list_isempty(&(futex->waiting_thread)) && number)
{
rt_thread_t thread;
thread = rt_list_entry(futex->waiting_thread.next, struct rt_thread, tlist);
/* remove from waiting list */
rt_list_remove(&(thread->tlist));
thread->error = RT_EOK;
/* resume the suspended thread */
rt_thread_resume(thread);
number--;
}
rt_mutex_release(&_futex_lock);
rt_hw_interrupt_enable(level);
/* do schedule */
rt_schedule();
}
#include <syscall_generic.h>
sysret_t sys_futex(int *uaddr, int op, int val, const struct timespec *timeout,
int *uaddr2, int val3)
{
struct rt_lwp *lwp = RT_NULL;
struct rt_futex *futex = RT_NULL;
int ret = 0;
rt_err_t lock_ret = 0;
if (!lwp_user_accessable(uaddr, sizeof(int)))
{
rt_set_errno(EINVAL);
return -RT_EINVAL;
}
/**
* if (op & (FUTEX_WAKE|FUTEX_FD|FUTEX_WAKE_BITSET|FUTEX_TRYLOCK_PI|FUTEX_UNLOCK_PI)) was TRUE
* `timeout` should be ignored by implementation, according to POSIX futex(2) manual.
* since only FUTEX_WAKE is implemented in rt-smart, only FUTEX_WAKE was omitted currently
*/
if (timeout && !(op & (FUTEX_WAKE)))
{
if (!lwp_user_accessable((void *)timeout, sizeof(struct timespec)))
{
rt_set_errno(EINVAL);
return -RT_EINVAL;
}
}
lock_ret = rt_mutex_take_interruptible(&_futex_lock, RT_WAITING_FOREVER);
if (lock_ret != RT_EOK)
{
rt_set_errno(EAGAIN);
return -RT_EINTR;
}
lwp = lwp_self();
futex = futex_get(uaddr, lwp);
if (futex == RT_NULL)
{
/* create a futex according to this uaddr */
futex = futex_create(uaddr, lwp);
if (futex == RT_NULL)
{
rt_mutex_release(&_futex_lock);
rt_set_errno(ENOMEM);
return -RT_ENOMEM;
}
if (lwp_user_object_add(lwp, futex->custom_obj) != 0)
{
rt_custom_object_destroy(futex->custom_obj);
rt_mutex_release(&_futex_lock);
rt_set_errno(ENOMEM);
return -RT_ENOMEM;
}
}
switch (op)
{
case FUTEX_WAIT:
ret = futex_wait(futex, val, timeout);
/* _futex_lock is released by futex_wait */
break;
case FUTEX_WAKE:
futex_wake(futex, val);
/* _futex_lock is released by futex_wake */
break;
default:
rt_mutex_release(&_futex_lock);
rt_set_errno(ENOSYS);
ret = -ENOSYS;
break;
}
return ret;
}
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