98 lines
3.7 KiB
C
98 lines
3.7 KiB
C
/****************************************************************************
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* libc/fixedmath/tls_cpuindex.c
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*
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* Copyright (C) 2016 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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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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* 1. 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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* 2. 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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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* 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
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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 <assert.h>
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#include <nuttx/arch.h>
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#include <nuttx/sched.h>
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#include <nuttx/tls.h>
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#if defined(CONFIG_TLS) && defined(CONFIG_SMP)
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: tls_cpu_index
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*
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* Description:
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* Return an index in the range of 0 through (CONFIG_SMP_NCPUS-1) that
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* corresponds to the currently executing CPU. This is index is retained
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* in the task TCB which is accessible via the tls_info_s structure.
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*
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* There is a race condition in that this thread could be swapped out and
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* be running on a different CPU when the function returns. If that is a
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* problem, then the calling function should disable pre-emption before
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* calling this function.
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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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* On success, an integer index is returned in the range of 0 through
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* (CONFIG_SMP_NCPUS-1) that corresponds to the currently executing CPU.
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*
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****************************************************************************/
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int tls_cpu_index(void)
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{
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FAR struct tls_info_s *info;
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FAR struct tcb_s *tcb;
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/* Get the TLS info structure from the current threads stack */
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info = up_tls_info();
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DEBUGASSERT(info != NULL && info->tl_tcb != NULL);
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/* Get the TCB from the TLS info. We expect the TCB state to indicate that
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* the task is running (it must be because it is this thread).
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*/
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tcb = info->tl_tcb;
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DEBUGASSERT(tcb->task_state == TSTATE_TASK_RUNNING &&
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tcb->cpu <= (CONFIG_SMP_NCPUS-1));
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return tcb->cpu;
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}
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#endif /* CONFIG_TLS && CONFIG_SMP */
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