107 lines
2.9 KiB
C
107 lines
2.9 KiB
C
/****************************************************************************
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* libs/libc/tls/tls_alloc.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sched.h>
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#include <errno.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/spinlock.h>
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#include <nuttx/tls.h>
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#if CONFIG_TLS_NELEM > 0
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: tls_alloc
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*
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* Description:
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* Allocate a group-unique TLS data index
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*
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* Input Parameters:
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* None
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*
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* Returned Value:
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* A TLS index that is unique for use within this task group.
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* If unsuccessful, an errno value will be returned and set to errno.
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*
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****************************************************************************/
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int tls_alloc(void)
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{
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FAR struct task_info_s *tinfo = task_get_info();
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int candidate;
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int ret = -EAGAIN;
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DEBUGASSERT(tinfo != NULL);
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/* Search for an unused index. This is done in a critical section here to
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* avoid concurrent modification of the group TLS index set.
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*/
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ret = _SEM_WAIT(&tinfo->ta_tlssem);
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if (ERROR == ret)
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{
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ret = -get_errno();
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goto errout_with_errno;
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}
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for (candidate = 0; candidate < CONFIG_TLS_NELEM; candidate++)
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{
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/* Is this candidate index available? */
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tls_ndxset_t mask = (1 << candidate);
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if ((tinfo->ta_tlsset & mask) == 0)
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{
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/* Yes.. allocate the index and break out of the loop */
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tinfo->ta_tlsset |= mask;
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break;
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}
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}
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_SEM_POST(&tinfo->ta_tlssem);
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/* Check if found a valid TLS data index. */
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if (candidate < CONFIG_TLS_NELEM)
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{
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/* Yes.. Return the TLS index and success */
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ret = candidate;
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}
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errout_with_errno:
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return ret;
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}
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#endif /* CONFIG_TLS_NELEM > 0 */
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