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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/include/kernel/futexmgr.H $ */
/* */
/* OpenPOWER HostBoot Project */
/* */
/* COPYRIGHT International Business Machines Corp. 2011,2014 */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef FUTEXMGR
#define FUTEXMGR
/**
* @file futexmgr.H
* @brief Declaration for kernel side futex management
*/
#include <stdint.h>
#include <util/locked/list.H>
#include <kernel/spinlock.H>
struct task_t;
/**
* @class FutexManager
* Kernel internal management of fuxtexs
*/
class FutexManager
{
public:
/**
* Put the current processes on a wait queue
* @param[in] i_task pointer to the current task structure
* @param[in] i_addr Futex address
* @param[in] i_val Value that *i_addr should contain
* @returns [0 | error code] if *i_addr != i_val returns EWOULDBLOCK
*/
static uint64_t wait(task_t * i_task, uint64_t * i_addr, uint64_t i_val);
/**
* Wakeup and optionally move waiting processes.
* @param[in] i_futex1 pointer to a futex
* @param[in] i_count1 The max number of tasks to wake
* @param[in] i_futex2 pointer to a futex, (default NULL) Optional
* futex to move i_count_2 unwoken tasks to.
* @param[in] i_count2 The max number of theads to move from futex1 to
* futex2. (default 0)
*
* @returns The number of tasks awoken
*/
static uint64_t wake(uint64_t * i_futex1, uint64_t i_count1,
uint64_t * i_futex2 = NULL, uint64_t i_count2 = 0);
protected:
/**
* Ctor
*/
FutexManager() {};
/**
* Dtor
*/
~FutexManager() {};
private: // functions
/** see wait(...) */
uint64_t _wait(task_t * i_task, uint64_t * i_addr, uint64_t i_val);
/** see wake(...) */
uint64_t _wake(uint64_t * i_futex1, uint64_t i_count1,
uint64_t * i_futex2, uint64_t i_count2);
private: // data
struct _FutexWait_t
{
_FutexWait_t * next; ///< next _FutexWait_t in list
_FutexWait_t * prev; ///< prev _FutexWait_t in list
uint64_t * key; ///< search key is futex address
task_t* task; ///< task on wait list
};
typedef Util::Locked::List<_FutexWait_t, uint64_t *> FutexList_t;
Spinlock iv_lock; ///< lock
FutexList_t iv_list; ///< List of waiting tasks for all futexes
};
#endif
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