incubator-nuttx/sched/group/group_tlsalloc.c

102 lines
2.9 KiB
C

/****************************************************************************
* sched/group/group_tlsalloc.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sched.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/tls.h>
#include "sched/sched.h"
#include "group/group.h"
#if CONFIG_TLS_NELEM > 0
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tls_alloc
*
* Description:
* Allocate a group-unique TLS data index
*
* Input Parameters:
* None
*
* Returned Value:
* A TLS index that is unique for use within this task group.
*
****************************************************************************/
int tls_alloc(void)
{
FAR struct tcb_s *rtcb = this_task();
FAR struct task_group_s *group = rtcb->group;
irqstate_t flags;
int candidate;
int ret = -EAGAIN;
DEBUGASSERT(group != NULL);
/* Search for an unused index. This is done in a critical section here to
* avoid concurrent modification of the group TLS index set.
*/
flags = spin_lock_irqsave();
for (candidate = 0; candidate < CONFIG_TLS_NELEM; candidate++)
{
/* Is this candidate index available? */
tls_ndxset_t mask = (1 << candidate);
if ((group->tg_tlsset & mask) == 0)
{
/* Yes.. allocate the index and break out of the loop */
group->tg_tlsset |= mask;
break;
}
}
spin_unlock_irqrestore(flags);
/* Check if found a valid TLS data index. */
if (candidate < CONFIG_TLS_NELEM)
{
/* Yes.. Return the TLS index and success */
ret = candidate;
}
return ret;
}
#endif /* CONFIG_TLS_NELEM > 0 */