add a basic spinlock, which based on a ticket lock

This commit is contained in:
Stefan Lankes 2013-11-26 09:15:43 +01:00
parent 949cbb5119
commit ab28a5e612
3 changed files with 198 additions and 0 deletions

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@ -125,6 +125,8 @@ static inline size_t lsb(size_t i)
#define NOP4 asm volatile ("nop;nop;nop;nop")
/// A eight-instruction-do-nothing
#define NOP8 asm volatile ("nop;nop;nop;nop;nop;nop;nop;nop")
/// The PAUSE instruction provides a hint to the processor that the code sequence is a spin-wait loop.
#define PAUSE asm volatile ("pause")
#ifdef __cplusplus
}

132
include/eduos/spinlock.h Normal file
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@ -0,0 +1,132 @@
/*
* Copyright (c) 2011, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @author Stefan Lankes
* @file include/eduos/spinlock.h
* @brief Spinlock functions
*/
#ifndef __SPINLOCK_H__
#define __SPINLOCK_H__
#include <eduos/stddef.h>
#include <eduos/spinlock_types.h>
#include <eduos/tasks_types.h>
#include <eduos/errno.h>
#include <asm/atomic.h>
#include <asm/processor.h>
#ifdef __cplusplus
extern "C" {
#endif
/** @brief Initialization of a spinlock
*
* Initialize each spinlock before use!
*
* @param s Pointer to the spinlock structure to initialize.
* @return
* - 0 on success
* - -EINVAL (-22) on failure
*/
inline static int spinlock_init(spinlock_t* s) {
if (BUILTIN_EXPECT(!s, 0))
return -EINVAL;
atomic_int32_set(&s->queue, 0);
atomic_int32_set(&s->dequeue, 1);
s->owner = MAX_TASKS;
s->counter = 0;
return 0;
}
/** @brief Destroy spinlock after use
* @return
* - 0 on success
* - -EINVAL (-22) on failure
*/
inline static int spinlock_destroy(spinlock_t* s) {
if (BUILTIN_EXPECT(!s, 0))
return -EINVAL;
s->owner = MAX_TASKS;
s->counter = 0;
return 0;
}
/** @brief Lock spinlock at entry of critical section
* @return
* - 0 on success
* - -EINVAL (-22) on failure
*/
inline static int spinlock_lock(spinlock_t* s) {
int32_t ticket;
if (BUILTIN_EXPECT(!s, 0))
return -EINVAL;
if (s->owner == current_task->id) {
s->counter++;
return 0;
}
ticket = atomic_int32_add(&s->queue, 1);
while(atomic_int32_read(&s->dequeue) != ticket) {
PAUSE;
}
s->owner = current_task->id;
s->counter = 1;
return 0;
}
/** @brief Unlock spinlock on exit of critical section
* @return
* - 0 on success
* - -EINVAL (-22) on failure
*/
inline static int spinlock_unlock(spinlock_t* s) {
if (BUILTIN_EXPECT(!s, 0))
return -EINVAL;
s->counter--;
if (!s->counter) {
s->owner = MAX_TASKS;
atomic_int32_inc(&s->dequeue);
}
return 0;
}
#ifdef __cplusplus
}
#endif
#endif

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@ -0,0 +1,64 @@
/*
* Copyright (c) 2011, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @author Stefan Lankes
* @file include/eduos/spinlock_types.h
* @brief Spinlock type definition
*/
#ifndef __SPINLOCK_TYPES_H__
#define __SPINLOCK_TYPES_H__
#include <eduos/stddef.h>
#include <asm/atomic.h>
#ifdef __cplusplus
extern "C" {
#endif
/** @brief Spinlock structure */
typedef struct spinlock {
/// Internal queue
atomic_int32_t queue;
/// Internal dequeue
atomic_int32_t dequeue;
/// Owner of this spinlock structure
tid_t owner;
/// Internal counter var
uint32_t counter;
} spinlock_t;
/// Macro for spinlock initialization
#define SPINLOCK_INIT { ATOMIC_INIT(0), ATOMIC_INIT(1), MAX_TASKS, 0}
#ifdef __cplusplus
}
#endif
#endif