936 lines
24 KiB
C
936 lines
24 KiB
C
/*
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* Copyright (c) 2006-2023, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2021/01/02 bernard the first version
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* 2023-07-25 Shell Remove usage of rt_hw_interrupt API in the lwp
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* Coding style: remove multiple `return` in a routine
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* 2023-08-08 Shell Fix return value of futex(wait); Fix ops that only
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* FUTEX_PRIVATE is supported currently
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* 2023-11-03 Shell Add Support for ~FUTEX_PRIVATE
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* 2023-11-16 xqyjlj Add Support for futex requeue and futex pi
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*/
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#define __RT_IPC_SOURCE__
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#include "lwp_futex_internal.h"
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#include "sys/time.h"
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#include <stdatomic.h>
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struct rt_mutex _glob_futex;
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rt_err_t lwp_futex_init(void)
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{
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return rt_mutex_init(&_glob_futex, "glob_ftx", RT_IPC_FLAG_PRIO);
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}
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static void _futex_lock(rt_lwp_t lwp, int op_flags)
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{
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rt_err_t error;
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if (op_flags & FUTEX_PRIVATE)
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{
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LWP_LOCK(lwp);
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}
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else
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{
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error = lwp_mutex_take_safe(&_glob_futex, RT_WAITING_FOREVER, 0);
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if (error)
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{
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LOG_E("%s: Should not failed", __func__);
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RT_ASSERT(0);
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}
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}
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}
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static void _futex_unlock(rt_lwp_t lwp, int op_flags)
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{
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rt_err_t error;
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if (op_flags & FUTEX_PRIVATE)
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{
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LWP_UNLOCK(lwp);
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}
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else
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{
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error = lwp_mutex_release_safe(&_glob_futex);
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if (error)
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{
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LOG_E("%s: Should not failed", __func__);
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RT_ASSERT(0);
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}
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}
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}
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/**
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* Destroy a Private FuTeX (pftx)
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* Note: must have futex address_search_head taken
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*/
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static rt_err_t _pftx_destroy_locked(void *data)
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{
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rt_err_t ret = -1;
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rt_futex_t futex = (rt_futex_t)data;
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if (futex)
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{
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/**
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* Brief: Delete the futex from lwp address_search_head
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*
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* Note: Critical Section
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* - the lwp (READ. share by thread)
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* - the lwp address_search_head (RW. protected by caller. for destroy
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* routine, it's always safe because it has already taken a write lock
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* to the lwp.)
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*/
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lwp_avl_remove(&futex->node,
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(struct lwp_avl_struct **)futex->node.data);
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/* release object */
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if (futex->mutex)
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{
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rt_mutex_delete(futex->mutex);
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futex->mutex = RT_NULL;
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}
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rt_free(futex);
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ret = 0;
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}
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return ret;
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}
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/**
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* Create a Private FuTeX (pftx)
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* Note: must have futex address_search_head taken
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*/
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static rt_futex_t _pftx_create_locked(int *uaddr, struct rt_lwp *lwp)
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{
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rt_futex_t futex = RT_NULL;
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struct rt_object *obj = RT_NULL;
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/**
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* Brief: Create a futex under current lwp
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*
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* Note: Critical Section
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* - lwp (READ; share with thread)
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*/
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if (lwp)
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{
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futex = (rt_futex_t)rt_malloc(sizeof(struct rt_futex));
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if (futex)
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{
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/* Create a Private FuTeX (pftx) */
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obj = rt_custom_object_create("pftx", (void *)futex,
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_pftx_destroy_locked);
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if (!obj)
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{
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rt_free(futex);
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futex = RT_NULL;
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}
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else
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{
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/**
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* Brief: Add futex to user object tree for resource recycling
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*
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* Note: Critical Section
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* - lwp user object tree (RW; protected by API)
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* - futex (if the adding is successful, others can find the
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* unready futex. However, only the lwp_free will do this,
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* and this is protected by the ref taken by the lwp thread
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* that the lwp_free will never execute at the same time)
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*/
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if (lwp_user_object_add(lwp, obj))
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{
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/* this will call a _pftx_destroy_locked, but that's okay */
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rt_object_delete(obj);
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rt_free(futex);
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futex = RT_NULL;
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}
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else
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{
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futex->node.avl_key = (avl_key_t)uaddr;
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futex->node.data = &lwp->address_search_head;
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futex->custom_obj = obj;
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futex->mutex = RT_NULL;
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rt_list_init(&(futex->waiting_thread));
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/**
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* Brief: Insert into futex head
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*
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* Note: Critical Section
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* - lwp address_search_head (RW; protected by caller)
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*/
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lwp_avl_insert(&futex->node, &lwp->address_search_head);
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}
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}
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}
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}
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return futex;
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}
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/**
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* Get a Private FuTeX (pftx) match the (lwp, uaddr, op)
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*/
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static rt_futex_t _pftx_get(void *uaddr, struct rt_lwp *lwp, int op,
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rt_err_t *rc)
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{
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struct lwp_avl_struct *node = RT_NULL;
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rt_futex_t futex = RT_NULL;
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rt_err_t error = -1;
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LWP_LOCK(lwp);
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/**
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* Note: Critical Section
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* protect lwp address_search_head (READ)
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*/
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node = lwp_avl_find((avl_key_t)uaddr, lwp->address_search_head);
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if (node)
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{
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futex = rt_container_of(node, struct rt_futex, node);
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error = 0;
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}
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else
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{
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/* create a futex according to this uaddr */
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futex = _pftx_create_locked(uaddr, lwp);
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if (!futex)
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error = -ENOMEM;
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else
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error = 0;
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}
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LWP_UNLOCK(lwp);
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*rc = error;
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return futex;
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}
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/**
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* Destroy a Shared FuTeX (pftx)
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* Note: must have futex address_search_head taken
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*/
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static rt_err_t _sftx_destroy(void *data)
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{
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rt_err_t ret = -1;
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rt_futex_t futex = (rt_futex_t)data;
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if (futex)
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{
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/* delete it even it's not in the table */
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futex_global_table_delete(&futex->entry.key);
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if (futex->mutex)
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{
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rt_mutex_delete(futex->mutex);
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futex->mutex = RT_NULL;
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}
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rt_free(futex);
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ret = 0;
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}
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return ret;
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}
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/**
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* Create a Shared FuTeX (sftx)
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*/
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static rt_futex_t _sftx_create(struct shared_futex_key *key, struct rt_lwp *lwp)
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{
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rt_futex_t futex = RT_NULL;
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struct rt_object *obj = RT_NULL;
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if (lwp)
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{
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futex = (rt_futex_t)rt_calloc(1, sizeof(struct rt_futex));
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if (futex)
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{
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/* create a Shared FuTeX (sftx) */
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obj = rt_custom_object_create("sftx", (void *)futex, _sftx_destroy);
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if (!obj)
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{
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rt_free(futex);
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futex = RT_NULL;
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}
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else
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{
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if (futex_global_table_add(key, futex))
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{
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rt_object_delete(obj);
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rt_free(futex);
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futex = RT_NULL;
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}
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else
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{
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futex->mutex = RT_NULL;
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rt_list_init(&(futex->waiting_thread));
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futex->custom_obj = obj;
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}
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}
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}
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}
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return futex;
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}
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/**
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* Get a Shared FuTeX (sftx) match the (lwp, uaddr, op)
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*/
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static rt_futex_t _sftx_get(void *uaddr, struct rt_lwp *lwp, int op,
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rt_err_t *rc)
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{
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rt_futex_t futex = RT_NULL;
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struct shared_futex_key key;
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rt_varea_t varea;
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rt_err_t error = -1;
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RD_LOCK(lwp->aspace);
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varea = rt_aspace_query(lwp->aspace, uaddr);
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if (varea)
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{
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key.mobj = varea->mem_obj;
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key.offset = ((varea->offset) << MM_PAGE_SHIFT) |
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((long)uaddr & ((1 << MM_PAGE_SHIFT) - 1));
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RD_UNLOCK(lwp->aspace);
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/* query for the key */
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_futex_lock(lwp, op & ~FUTEX_PRIVATE);
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error = futex_global_table_find(&key, &futex);
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if (error != RT_EOK)
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{
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/* not found, do allocation */
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futex = _sftx_create(&key, lwp);
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if (!futex)
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error = -ENOMEM;
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else
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error = 0;
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}
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_futex_unlock(lwp, op & ~FUTEX_PRIVATE);
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}
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else
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{
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RD_UNLOCK(lwp->aspace);
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}
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*rc = error;
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return futex;
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}
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/* must have futex address_search_head taken */
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static rt_futex_t _futex_get(void *uaddr, struct rt_lwp *lwp, int op_flags,
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rt_err_t *rc)
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{
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rt_futex_t futex = RT_NULL;
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if (op_flags & FUTEX_PRIVATE)
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{
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futex = _pftx_get(uaddr, lwp, op_flags, rc);
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}
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else
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{
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futex = _sftx_get(uaddr, lwp, op_flags, rc);
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}
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return futex;
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}
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static rt_err_t _suspend_thread_timeout_locked(rt_thread_t thread,
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rt_futex_t futex,
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rt_tick_t timeout)
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{
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rt_err_t rc;
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/**
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* Brief: Add current thread into futex waiting thread list
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*
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* Note: Critical Section
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* - the futex waiting_thread list (RW)
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*/
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rc = rt_thread_suspend_to_list(thread, &futex->waiting_thread,
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RT_IPC_FLAG_FIFO, RT_INTERRUPTIBLE);
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if (rc == RT_EOK)
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{
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/* start the timer of thread */
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rt_timer_control(&(thread->thread_timer), RT_TIMER_CTRL_SET_TIME,
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&timeout);
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rt_timer_start(&(thread->thread_timer));
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rt_set_errno(ETIMEDOUT);
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}
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return rc;
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}
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static rt_err_t _suspend_thread_locked(rt_thread_t thread, rt_futex_t futex)
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{
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/**
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* Brief: Add current thread into futex waiting thread list
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*
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* Note: Critical Section
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* - the futex waiting_thread list (RW)
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*/
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return rt_thread_suspend_to_list(thread, &futex->waiting_thread,
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RT_IPC_FLAG_FIFO, RT_INTERRUPTIBLE);
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}
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rt_inline int _futex_cmpxchg_value(int *curval, int *uaddr, int uval,
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int newval)
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{
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int err = 0;
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if (!lwp_user_accessable((void *)uaddr, sizeof(*uaddr)))
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{
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err = -EFAULT;
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goto exit;
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}
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if (!atomic_compare_exchange_strong(uaddr, &uval, newval))
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{
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*curval = uval;
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err = -EAGAIN;
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}
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exit:
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return err;
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}
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static int _futex_wait(rt_futex_t futex, struct rt_lwp *lwp, int *uaddr,
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int value, const struct timespec *timeout, int op_flags)
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{
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rt_tick_t to;
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rt_thread_t thread;
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rt_err_t rc = -RT_EINTR;
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/**
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* Brief: Remove current thread from scheduler, besides appends it to
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* the waiting thread list of the futex. If the timeout is specified
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* a timer will be setup for current thread
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*
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* Note: Critical Section
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* - futex.waiting (RW; Protected by lwp_lock)
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* - the local cpu
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*/
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_futex_lock(lwp, op_flags);
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if (*uaddr == value)
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{
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thread = rt_thread_self();
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if (timeout)
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{
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to = timeout->tv_sec * RT_TICK_PER_SECOND;
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to +=
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(timeout->tv_nsec * RT_TICK_PER_SECOND) / NANOSECOND_PER_SECOND;
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if (to < 0)
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{
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rc = -EINVAL;
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_futex_unlock(lwp, op_flags);
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}
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else
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{
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rt_enter_critical();
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rc = _suspend_thread_timeout_locked(thread, futex, to);
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_futex_unlock(lwp, op_flags);
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rt_exit_critical();
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}
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}
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else
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{
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rt_enter_critical();
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rc = _suspend_thread_locked(thread, futex);
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_futex_unlock(lwp, op_flags);
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rt_exit_critical();
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}
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if (rc == RT_EOK)
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{
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/* do schedule */
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rt_schedule();
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/* check errno */
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rc = rt_get_errno();
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rc = rc > 0 ? -rc : rc;
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}
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}
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else
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{
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_futex_unlock(lwp, op_flags);
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rc = -EAGAIN;
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rt_set_errno(EAGAIN);
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}
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return rc;
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}
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|
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static long _futex_wake(rt_futex_t futex, struct rt_lwp *lwp, int number,
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int op_flags)
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{
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long woken_cnt = 0;
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int is_empty = 0;
|
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|
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/**
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* Brief: Wakeup a suspended thread on the futex waiting thread list
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*
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* Note: Critical Section
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* - the futex waiting_thread list (RW)
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*/
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while (number && !is_empty)
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{
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_futex_lock(lwp, op_flags);
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if (rt_susp_list_dequeue(&futex->waiting_thread, RT_EOK))
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{
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number--;
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woken_cnt++;
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}
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_futex_unlock(lwp, op_flags);
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}
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|
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/* do schedule */
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rt_schedule();
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return woken_cnt;
|
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}
|
|
|
|
/**
|
|
* Brief: Wake up to nr_wake futex1 threads.
|
|
* If there are more waiters waiting on futex1 than nr_wake,
|
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* insert the remaining at most nr_requeue waiters waiting
|
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* on futex1 into the waiting queue of futex2.
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*/
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static long _futex_requeue(rt_futex_t futex1, rt_futex_t futex2,
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struct rt_lwp *lwp, int nr_wake, int nr_requeue,
|
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int opflags)
|
|
{
|
|
long rtn;
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long woken_cnt = 0;
|
|
int is_empty = 0;
|
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rt_thread_t thread;
|
|
|
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if (futex1 == futex2)
|
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{
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return -EINVAL;
|
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}
|
|
|
|
/**
|
|
* Brief: Wakeup a suspended thread on the futex waiting thread list
|
|
*
|
|
* Note: Critical Section
|
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* - the futex waiting_thread list (RW)
|
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*/
|
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while (nr_wake && !is_empty)
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{
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rt_sched_lock_level_t slvl;
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rt_sched_lock(&slvl);
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is_empty = rt_list_isempty(&(futex1->waiting_thread));
|
|
if (!is_empty)
|
|
{
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thread = RT_THREAD_LIST_NODE_ENTRY(futex1->waiting_thread.next);
|
|
/* remove from waiting list */
|
|
rt_list_remove(&RT_THREAD_LIST_NODE(thread));
|
|
|
|
thread->error = RT_EOK;
|
|
/* resume the suspended thread */
|
|
rt_thread_resume(thread);
|
|
|
|
nr_wake--;
|
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woken_cnt++;
|
|
}
|
|
rt_sched_unlock(slvl);
|
|
}
|
|
rtn = woken_cnt;
|
|
|
|
/**
|
|
* Brief: Requeue
|
|
*
|
|
* Note: Critical Section
|
|
* - the futex waiting_thread list (RW)
|
|
*/
|
|
while (!is_empty && nr_requeue)
|
|
{
|
|
rt_sched_lock_level_t slvl;
|
|
rt_sched_lock(&slvl);
|
|
is_empty = rt_list_isempty(&(futex1->waiting_thread));
|
|
if (!is_empty)
|
|
{
|
|
thread = RT_THREAD_LIST_NODE_ENTRY(futex1->waiting_thread.next);
|
|
rt_list_remove(&RT_THREAD_LIST_NODE(thread));
|
|
rt_list_insert_before(&(futex2->waiting_thread),
|
|
&RT_THREAD_LIST_NODE(thread));
|
|
nr_requeue--;
|
|
rtn++;
|
|
}
|
|
rt_sched_unlock(slvl);
|
|
}
|
|
|
|
/* do schedule */
|
|
rt_schedule();
|
|
|
|
return rtn;
|
|
}
|
|
|
|
/* timeout argument measured against the CLOCK_REALTIME clock. */
|
|
static long _futex_lock_pi(rt_futex_t futex, struct rt_lwp *lwp, int *uaddr,
|
|
const struct timespec *timeout, int op_flags,
|
|
rt_bool_t trylock)
|
|
{
|
|
int word = 0, nword, cword;
|
|
int tid = 0;
|
|
rt_err_t err = 0;
|
|
rt_thread_t thread = RT_NULL, current_thread = RT_NULL;
|
|
rt_tick_t to = RT_WAITING_FOREVER;
|
|
|
|
if (!lwp_user_accessable((void *)uaddr, sizeof(*uaddr)))
|
|
{
|
|
return -EFAULT;
|
|
}
|
|
|
|
current_thread = rt_thread_self();
|
|
|
|
_futex_lock(lwp, op_flags);
|
|
|
|
lwp_get_from_user(&word, (void *)uaddr, sizeof(int));
|
|
tid = word & FUTEX_TID_MASK;
|
|
if (word == 0)
|
|
{
|
|
/* If the value is 0, then the kernel tries
|
|
to atomically set the futex value to the caller's TID. */
|
|
nword = current_thread->tid;
|
|
if (_futex_cmpxchg_value(&cword, uaddr, word, nword))
|
|
{
|
|
_futex_unlock(lwp, op_flags);
|
|
return -EAGAIN;
|
|
}
|
|
_futex_unlock(lwp, op_flags);
|
|
return 0;
|
|
}
|
|
else
|
|
{
|
|
thread = lwp_tid_get_thread_and_inc_ref(tid);
|
|
if (thread == RT_NULL)
|
|
{
|
|
_futex_unlock(lwp, op_flags);
|
|
return -ESRCH;
|
|
}
|
|
lwp_tid_dec_ref(thread);
|
|
|
|
nword =
|
|
word | FUTEX_WAITERS;
|
|
if (_futex_cmpxchg_value(&cword, uaddr, word, nword))
|
|
{
|
|
_futex_unlock(lwp, op_flags);
|
|
return -EAGAIN;
|
|
}
|
|
word = nword;
|
|
}
|
|
|
|
if (futex->mutex == RT_NULL)
|
|
{
|
|
futex->mutex = rt_mutex_create("futexpi", RT_IPC_FLAG_PRIO);
|
|
if (futex->mutex == RT_NULL)
|
|
{
|
|
_futex_unlock(lwp, op_flags);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* set mutex->owner */
|
|
rt_spin_lock(&(futex->mutex->spinlock));
|
|
futex->mutex->owner = thread;
|
|
futex->mutex->hold = 1;
|
|
rt_spin_unlock(&(futex->mutex->spinlock));
|
|
}
|
|
if (timeout)
|
|
{
|
|
to = rt_timespec_to_tick(timeout);
|
|
}
|
|
|
|
if (trylock)
|
|
{
|
|
to = RT_WAITING_NO;
|
|
}
|
|
_futex_unlock(lwp, op_flags);
|
|
|
|
err = rt_mutex_take_interruptible(futex->mutex, to);
|
|
if (err == -RT_ETIMEOUT)
|
|
{
|
|
err = -EDEADLK;
|
|
}
|
|
|
|
_futex_lock(lwp, op_flags);
|
|
nword = current_thread->tid | FUTEX_WAITERS;
|
|
if (_futex_cmpxchg_value(&cword, uaddr, word, nword))
|
|
{
|
|
err = -EAGAIN;
|
|
}
|
|
_futex_unlock(lwp, op_flags);
|
|
|
|
return err;
|
|
}
|
|
|
|
static long _futex_unlock_pi(rt_futex_t futex, struct rt_lwp *lwp, int op_flags)
|
|
{
|
|
rt_err_t err = 0;
|
|
_futex_lock(lwp, op_flags);
|
|
if (!futex->mutex)
|
|
{
|
|
_futex_unlock(lwp, op_flags);
|
|
return -EPERM;
|
|
}
|
|
_futex_unlock(lwp, op_flags);
|
|
|
|
err = rt_mutex_release(futex->mutex);
|
|
return err;
|
|
}
|
|
|
|
#include <syscall_generic.h>
|
|
|
|
rt_inline rt_bool_t _timeout_ignored(int op)
|
|
{
|
|
/**
|
|
* 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
|
|
*/
|
|
return ((op & (FUTEX_WAKE)) || (op & (FUTEX_REQUEUE)) ||
|
|
(op & (FUTEX_CMP_REQUEUE)) || (op & (FUTEX_UNLOCK_PI)) ||
|
|
(op & (FUTEX_TRYLOCK_PI)));
|
|
}
|
|
|
|
sysret_t sys_futex(int *uaddr, int op, int val, const struct timespec *timeout,
|
|
int *uaddr2, int val3)
|
|
{
|
|
struct rt_lwp *lwp = RT_NULL;
|
|
sysret_t ret = 0;
|
|
|
|
if (!lwp_user_accessable(uaddr, sizeof(int)))
|
|
{
|
|
ret = -EFAULT;
|
|
}
|
|
else if (timeout && !_timeout_ignored(op) &&
|
|
!lwp_user_accessable((void *)timeout, sizeof(struct timespec)))
|
|
{
|
|
ret = -EINVAL;
|
|
}
|
|
else
|
|
{
|
|
lwp = lwp_self();
|
|
ret = lwp_futex(lwp, uaddr, op, val, timeout, uaddr2, val3);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
#define FUTEX_FLAGS (FUTEX_PRIVATE | FUTEX_CLOCK_REALTIME)
|
|
rt_err_t lwp_futex(struct rt_lwp *lwp, int *uaddr, int op, int val,
|
|
const struct timespec *timeout, int *uaddr2, int val3)
|
|
{
|
|
rt_futex_t futex, futex2;
|
|
rt_err_t rc = 0;
|
|
int op_type = op & ~FUTEX_FLAGS;
|
|
int op_flags = op & FUTEX_FLAGS;
|
|
|
|
futex = _futex_get(uaddr, lwp, op_flags, &rc);
|
|
if (!rc)
|
|
{
|
|
switch (op_type)
|
|
{
|
|
case FUTEX_WAIT:
|
|
rc = _futex_wait(futex, lwp, uaddr, val, timeout, op_flags);
|
|
break;
|
|
case FUTEX_WAKE:
|
|
rc = _futex_wake(futex, lwp, val, op_flags);
|
|
break;
|
|
case FUTEX_REQUEUE:
|
|
futex2 = _futex_get(uaddr2, lwp, op_flags, &rc);
|
|
if (!rc)
|
|
{
|
|
_futex_lock(lwp, op_flags);
|
|
rc = _futex_requeue(futex, futex2, lwp, val, (long)timeout,
|
|
op_flags);
|
|
_futex_unlock(lwp, op_flags);
|
|
}
|
|
break;
|
|
case FUTEX_CMP_REQUEUE:
|
|
futex2 = _futex_get(uaddr2, lwp, op_flags, &rc);
|
|
_futex_lock(lwp, op_flags);
|
|
if (*uaddr == val3)
|
|
{
|
|
rc = 0;
|
|
}
|
|
else
|
|
{
|
|
rc = -EAGAIN;
|
|
}
|
|
if (rc == 0)
|
|
{
|
|
rc = _futex_requeue(futex, futex2, lwp, val,
|
|
(long)timeout, op_flags);
|
|
}
|
|
_futex_unlock(lwp, op_flags);
|
|
break;
|
|
case FUTEX_LOCK_PI:
|
|
rc = _futex_lock_pi(futex, lwp, uaddr, timeout, op_flags,
|
|
RT_FALSE);
|
|
break;
|
|
case FUTEX_UNLOCK_PI:
|
|
rc = _futex_unlock_pi(futex, lwp, op_flags);
|
|
break;
|
|
case FUTEX_TRYLOCK_PI:
|
|
rc = _futex_lock_pi(futex, lwp, uaddr, 0, op_flags, RT_TRUE);
|
|
break;
|
|
default:
|
|
LOG_W("User require op=%d which is not implemented", op);
|
|
rc = -ENOSYS;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
rt_inline int _fetch_robust_entry(struct robust_list **entry,
|
|
struct robust_list **head, rt_bool_t *is_pi)
|
|
{
|
|
unsigned long uentry;
|
|
|
|
if (!lwp_user_accessable((void *)head, sizeof(*head)))
|
|
{
|
|
return -EFAULT;
|
|
}
|
|
|
|
if (lwp_get_from_user(&uentry, (void *)head, sizeof(*head)) !=
|
|
sizeof(*head))
|
|
{
|
|
return -EFAULT;
|
|
}
|
|
|
|
*entry = (void *)(uentry & ~1UL);
|
|
*is_pi = uentry & 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int _handle_futex_death(int *uaddr, rt_thread_t thread, rt_bool_t is_pi,
|
|
rt_bool_t is_pending_op)
|
|
{
|
|
int word, cword = 0, nword;
|
|
rt_err_t rc;
|
|
struct rt_lwp *lwp;
|
|
rt_futex_t futex;
|
|
|
|
/* Futex address must be 32bit aligned */
|
|
if ((((unsigned long)uaddr) % sizeof(*uaddr)) != 0)
|
|
return -1;
|
|
|
|
lwp = thread->lwp;
|
|
retry:
|
|
|
|
if (!lwp_user_accessable((void *)uaddr, sizeof(*uaddr)))
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
if (lwp_get_from_user(&word, (void *)uaddr, sizeof(*uaddr)) !=
|
|
sizeof(*uaddr))
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
futex = _futex_get(uaddr, lwp, FUTEX_PRIVATE, &rc);
|
|
if (is_pending_op && !is_pi && !word)
|
|
{
|
|
_futex_wake(futex, lwp, 1, FUTEX_PRIVATE);
|
|
return 0;
|
|
}
|
|
|
|
if ((word & FUTEX_TID_MASK) != thread->tid)
|
|
return 0;
|
|
|
|
nword = (word & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
|
|
|
|
if ((rc = _futex_cmpxchg_value(&cword, uaddr, word, nword)))
|
|
{
|
|
switch (rc)
|
|
{
|
|
case -EFAULT:
|
|
return -1;
|
|
case -EAGAIN:
|
|
rt_schedule();
|
|
goto retry;
|
|
default:
|
|
LOG_W("unknown errno: %d in '%s'", rc, __FUNCTION__);
|
|
return rc;
|
|
}
|
|
}
|
|
|
|
if (cword != word)
|
|
goto retry;
|
|
|
|
if (!is_pi && (word & FUTEX_WAITERS))
|
|
_futex_wake(futex, lwp, 1, FUTEX_PRIVATE);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Brief: Walk thread->robust_list mark
|
|
* any locks found there dead, and notify any waiters.
|
|
*
|
|
* note: very carefully, it's a userspace list!
|
|
*/
|
|
void lwp_futex_exit_robust_list(rt_thread_t thread)
|
|
{
|
|
struct robust_list *entry = RT_NULL;
|
|
struct robust_list *next_entry = RT_NULL;
|
|
struct robust_list *pending = RT_NULL;
|
|
struct robust_list_head *head;
|
|
unsigned int limit = 2048;
|
|
rt_bool_t pi, pip, next_pi;
|
|
unsigned long futex_offset;
|
|
int rc;
|
|
|
|
head = thread->robust_list;
|
|
|
|
if (head == RT_NULL)
|
|
return;
|
|
|
|
if (_fetch_robust_entry(&entry, &head->list.next, &pi))
|
|
return;
|
|
|
|
if (!lwp_user_accessable((void *)&head->futex_offset,
|
|
sizeof(head->futex_offset)))
|
|
{
|
|
return;
|
|
}
|
|
|
|
if (lwp_get_from_user(&futex_offset, (void *)&head->futex_offset,
|
|
sizeof(head->futex_offset)) !=
|
|
sizeof(head->futex_offset))
|
|
{
|
|
return;
|
|
}
|
|
|
|
if (_fetch_robust_entry(&pending, &head->list_op_pending, &pip))
|
|
{
|
|
return;
|
|
}
|
|
|
|
while (entry != &head->list)
|
|
{
|
|
rc = _fetch_robust_entry(&next_entry, &entry->next, &next_pi);
|
|
if (entry != pending)
|
|
{
|
|
if (_handle_futex_death((void *)entry + futex_offset, thread, pi,
|
|
RT_FALSE))
|
|
return;
|
|
}
|
|
if (rc)
|
|
return;
|
|
entry = next_entry;
|
|
pi = next_pi;
|
|
|
|
if (!--limit)
|
|
break;
|
|
}
|
|
|
|
if (pending)
|
|
{
|
|
_handle_futex_death((void *)pending + futex_offset, thread, pip,
|
|
RT_TRUE);
|
|
}
|
|
}
|