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incubator-nuttx/include/nuttx/tls.h

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/****************************************************************************
* include/nuttx/tls.h
*
* 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.
*
****************************************************************************/
#ifndef __INCLUDE_NUTTX_TLS_H
#define __INCLUDE_NUTTX_TLS_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/lib/getopt.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifdef CONFIG_TLS_ALIGNED
# ifndef CONFIG_TLS_LOG2_MAXSTACK
# error CONFIG_TLS_LOG2_MAXSTACK is not defined
# endif
#endif
#ifndef CONFIG_TLS_NELEM
# warning CONFIG_TLS_NELEM is not defined
# define CONFIG_TLS_NELEM 0
#endif
/* TLS Definitions **********************************************************/
#ifdef CONFIG_TLS_ALIGNED
# 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))
#endif
/****************************************************************************
* 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).
*
* The following diagram represent the typic stack layout:
*
* Push Down Push Up
* +-------------+ +-------------+ <- Stack memory allocation
* | TLS Data | | TLS Data |
* +-------------+ +-------------+
* | Task Data* | | Task Data* |
* +-------------+ +-------------+
* | Arguments | | Arguments |
* +-------------+ +-------------+ |
* | | | | v
* | Available | | Available |
* | Stack | | Stack |
* | | | |
* | | | |
* | | ^ | |
* +-------------+ | +-------------+
*
* Task data is allocated in the main's thread's stack only
*/
struct tls_info_s
{
#if CONFIG_TLS_NELEM > 0
uintptr_t tl_elem[CONFIG_TLS_NELEM]; /* TLS elements */
#endif
int tl_errno; /* Per-thread error number */
};
struct task_info_s
{
struct tls_info_s ta_tls; /* Must be first field */
#ifndef CONFIG_BUILD_KERNEL
struct getopt_s ta_getopt; /* Globals used by getopt() */
#endif
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* 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.
*
****************************************************************************/
#if CONFIG_TLS_NELEM > 0
int tls_alloc(void);
#endif
/****************************************************************************
* Name: tls_free
*
* Description:
* Release a group-unique TLS data index previous obtained by tls_alloc()
*
* Input Parameters:
* tlsindex - The previously allocated TLS index to be freed
*
* Returned Value:
* OK is returned on success; a negated errno value will be returned on
* failure:
*
* -EINVAL - the index to be freed is out of range.
*
****************************************************************************/
#if CONFIG_TLS_NELEM > 0
int tls_free(int tlsindex);
#endif
/****************************************************************************
* Name: tls_get_value
*
* Description:
* Return an the TLS data value associated with the 'tlsindx'
*
* Input Parameters:
* tlsindex - Index of TLS data element to return
*
* Returned Value:
* The value of TLS element associated with 'tlsindex'. Errors are not
* reported. Zero 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 tlsindex < 0 or tlsindex >=CONFIG_TLS_NELEM.
*
****************************************************************************/
#if CONFIG_TLS_NELEM > 0
uintptr_t tls_get_value(int tlsindex);
#endif
/****************************************************************************
* Name: tls_set_value
*
* Description:
* Set the TLS element associated with the 'tlsindex' to 'tlsvalue'
*
* Input Parameters:
* tlsindex - Index of TLS data element to set
* tlsvalue - The new value of the TLS data element
*
* Returned Value:
* Zero is returned on success, a negated errno value is return on
* failure:
*
* EINVAL - tlsindex is not in range.
*
****************************************************************************/
#if CONFIG_TLS_NELEM > 0
int tls_set_value(int tlsindex, uintptr_t tlsvalue);
#endif
/****************************************************************************
* Name: tls_get_info
*
* Description:
* Return a reference to the tls_info_s structure. This is used as part
* of the internal implementation of tls_get/set_elem() and ONLY for the
* where CONFIG_TLS_ALIGNED is *not* defined
*
* Input Parameters:
* None
*
* Returned Value:
* A reference to the thread-specific tls_info_s structure is return on
* success. NULL would be returned in the event of any failure.
*
****************************************************************************/
#ifndef CONFIG_TLS_ALIGNED
FAR struct tls_info_s *tls_get_info(void);
#endif
/****************************************************************************
* Name: task_get_info
*
* Description:
* Return a reference to the task_info_s structure.
*
* Input Parameters:
* None
*
* Returned Value:
* A reference to the task-specific task_info_s structure is return on
* success. NULL would be returned in the event of any failure.
*
****************************************************************************/
FAR struct task_info_s *task_get_info(void);
#endif /* __INCLUDE_NUTTX_TLS_H */
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