mirror of
https://github.com/intel/linux-sgx
synced 2026-06-08 14:49:32 +00:00
Haitao Huang
07f3e53376
This is to avoid unneeded ocall references in regular mutex implementation, which requires every enclave to import those ocalls in its EDL even if it does not need the mutex for synchronization. Signed-off-by: Haitao Huang <4699115+haitaohuang@users.noreply.github.com>
119 lines
3.4 KiB
C++
119 lines
3.4 KiB
C++
/*
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* Copyright (C) 2022 Intel Corporation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include "util.h"
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#include "sethread_internal.h"
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#include "sethread_spinlock.h"
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int sgx_thread_spin_init(sgx_thread_spinlock_t *mutex)
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{
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CHECK_PARAMETER(mutex);
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mutex->m_refcount = 0;
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mutex->m_owner = SGX_THREAD_T_NULL;
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mutex->m_lock = SGX_SPINLOCK_INITIALIZER;
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return 0;
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}
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int sgx_thread_spin_destroy(sgx_thread_spinlock_t *mutex)
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{
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CHECK_PARAMETER(mutex);
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SPIN_LOCK(&mutex->m_lock);
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if (mutex->m_owner != SGX_THREAD_T_NULL) {
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SPIN_UNLOCK(&mutex->m_lock);
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return EBUSY;
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}
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mutex->m_refcount = 0;
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SPIN_UNLOCK(&mutex->m_lock);
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return 0;
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}
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int sgx_thread_spin_trylock(sgx_thread_spinlock_t *mutex)
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{
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CHECK_PARAMETER(mutex);
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sgx_thread_t self = (sgx_thread_t)get_thread_data();
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SPIN_LOCK(&mutex->m_lock);
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if (mutex->m_owner == self) {
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mutex->m_refcount++;
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SPIN_UNLOCK(&mutex->m_lock);
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return 0;
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}
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if (mutex->m_owner == SGX_THREAD_T_NULL) {
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mutex->m_owner = self;
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mutex->m_refcount++;
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SPIN_UNLOCK(&mutex->m_lock);
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return 0;
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}
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SPIN_UNLOCK(&mutex->m_lock);
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return EBUSY;
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}
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int sgx_thread_spin_unlock(sgx_thread_spinlock_t *mutex)
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{
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CHECK_PARAMETER(mutex);
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sgx_thread_t self = (sgx_thread_t)get_thread_data();
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SPIN_LOCK(&mutex->m_lock);
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/* if the mutux is not locked by anyone */
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if(mutex->m_owner == SGX_THREAD_T_NULL) {
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SPIN_UNLOCK(&mutex->m_lock);
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return EPERM;
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}
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/* if the mutex is locked by another thread */
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if (mutex->m_owner != self) {
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SPIN_UNLOCK(&mutex->m_lock);
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return EPERM;
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}
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/* the mutex is locked by current thread */
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if (--mutex->m_refcount == 0) {
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mutex->m_owner = SGX_THREAD_T_NULL;
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}
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SPIN_UNLOCK(&mutex->m_lock);
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return 0;
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}
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