incubator-nuttx/include/nuttx/tls.h

141 lines
5.3 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
#ifndef CONFIG_TLS_NELEM
# warning CONFIG_TLS_NELEM is not defined
# define CONFIG_TLS_NELEM 1
#endif
#if CONFIG_TLS_NELEM < 1
# error CONFIG_TLS_NELEM must be at least one
# undef CONFIG_TLS_NELEM
# define CONFIG_TLS_NELEM 1
#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. TLS is not
* available from interrupt handlers (nor from the IDLE thread).
*/
struct tls_info_s
{
uintptr_t tl_elem[CONFIG_TLS_NELEM]; /* TLS elements */
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* Name: tls_get_element
*
* Description:
* Return an the TLS element associated with the 'elem' index
*
* Input Parameters:
* elem - Index of TLS element to return
*
* Returned Value:
* The value of TLS element associated with 'elem'. Errors are not reported.
* Aero is returned in the event of an error, but zero may also be valid
* value and returned when there is no error. The only possible error would
* be if elemn < 0 or elem >=CONFIG_TLS_NELEM.
*
****************************************************************************/
uintptr_t tls_get_element(int elem);
/****************************************************************************
* Name: tls_get_element
*
* Description:
* Set the TLS element associated with the 'elem' index to 'value'
*
* Input Parameters:
* elem - Index of TLS element to set
* value - The new value of the TLS element
*
* Returned Value:
* None. Errors are not reported. The only possible error would be if
* elem < 0 or elem >=CONFIG_TLS_NELEM.
*
****************************************************************************/
void tls_set_element(int elem, uintptr_t value);
#endif /* CONFIG_TLS */
#endif /* __INCLUDE_NUTTX_TLS_H */