nuttx/include/nuttx/tls.h
2016-03-10 18:10:44 -06:00

116 lines
4.5 KiB
C

/****************************************************************************
* include/nuttx/tls.h
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name NuttX 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
* COPYRIGHT OWNER 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.
*
****************************************************************************/
#ifndef __INCLUDE_NUTTX_TLS_H
#define __INCLUDE_NUTTX_TLS_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#ifdef CONFIG_TLS
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifndef CONFIG_TLS_LOG2_MAXSTACK
# error CONFIG_TLS_LOG2_MAXSTACK is not defined
#endif
/* TLS Definitions **********************************************************/
#define TLS_STACK_ALIGN (1L << CONFIG_TLS_LOG2_MAXSTACK)
#define TLS_STACK_MASK (TLS_STACK_ALIGN - 1)
#define TLS_MAXSTACK (TLS_STACK_ALIGN)
#define TLS_INFO(sp) ((FAR struct tls_info_s *)((sp) & ~TLS_STACK_MASK))
/****************************************************************************
* Public Types
****************************************************************************/
/* When TLS is enabled, up_createstack() will align allocated stacks to the
* TLS_STACK_ALIGN value. An instance of the following structure will be
* implicitly positioned at the "lower" end of the stack. Assuming a
* "push down" stack, this is at the "far" end of the stack (and can be
* clobbered if the stack overflows).
*
* If an MCU has a "push up" then that TLS structure will lie at the top
* of the stack and stack allocation and initialization logic must take
* care to preserve this structure content.
*
* The stack memory is fully accessible to user mode threads but will
* contain references to OS internal, private data structures (such as the
* TCB)
*/
struct tcb_s; /* Forward reference */
struct tls_info_s
{
FAR struct tcb_s *tl_tcb; /* The TCB of the current task */
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* Name: tls_cpu_index
*
* Description:
* Return an index in the range of 0 through (CONFIG_SMP_NCPUS-1) that
* corresponds to the currently executing CPU. This is index is retained
* in the task TCB which is accessible via the tls_info_s structure.
*
* Input Parameters:
* None
*
* Returned Value:
* An integer index in the range of 0 through (CONFIG_SMP_NCPUS-1) that
* corresponds to the currently executing CPU.
*
****************************************************************************/
#ifdef CONFIG_SMP
int tls_cpu_index(void);
#endif
#endif /* CONFIG_TLS */
#endif /* __INCLUDE_NUTTX_TLS_H */