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/************************************************************************
* sched/kmm_semaphore.c
*
* Copyright (C) 2011 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.
*
************************************************************************/
/************************************************************************
* Included Files
************************************************************************/
#include <nuttx/config.h>
#include <nuttx/kmalloc.h>
#ifdef CONFIG_NUTTX_KERNEL
/* This logic is all tentatively and, hopefully, will grow in usability.
* For now, the kernel-mode build uses the memory manager that is
* provided in the user-space build. That is awkward but reasonable for
* the current level of support: At present, only memory protection is
* provided. Kernel-mode code may call into user-mode code, but not
* vice-versa. So hosting the memory manager in user-space allows the
* memory manager to be shared in both kernel- and user-mode spaces.
*
* In the longer run, if an MMU is support that can provide virtualized
* memory, then some SLAB memory manager will be required in kernel-space
* with some kind of brk() system call to obtain mapped heap space.
*
* In the current build model, the user-space module is built first. The
* file user_map.h is generated in the first pass and contains the
* addresses of the memory manager needed in this file:
*/
#include <arch/board/user_map.h>
/************************************************************************
* Pre-processor definition
************************************************************************/
/* These values are obtained from user_map.h */
#define KTRYSEMAPHORE() ((kmtrysemaphore_t) CONFIG_USER_MMTRYSEM )()
#define KGIVESEMAPHORE() ((kmgivesemaphore_t)CONFIG_USER_MMGIVESEM)()
/************************************************************************
* Private Types
************************************************************************/
typedef int (*kmtrysemaphore_t)(void);
typedef void (*kmgivesemaphore_t)(void);
/************************************************************************
* Private Functions
************************************************************************/
/************************************************************************
* Public Functions
************************************************************************/
/************************************************************************
* Name: kmm_trysemaphore
*
* Description:
* This is a simple redirection to the user-space mm_trysemaphore()
* function.
*
* Parameters:
* None
*
* Return Value:
* OK on success; a negated errno on failure
*
* Assumptions:
* 1. mm_trysemaphore() resides in user-space
* 2. The address of the user space mm_trysemaphore() is provided in
* user_map.h
* 3. The user-space mm_semaphore() is callable from kernel-space.
*
************************************************************************/
int kmm_trysemaphore(void)
{
return KTRYSEMAPHORE();
}
/************************************************************************
* Name: kmm_givesemaphore
*
* Description:
* This is a simple redirection to the user-space mm_givesemaphore()
* function.
*
* Parameters:
* None
*
* Return Value:
* OK on success; a negated errno on failure
*
* Assumptions:
* 1. mm_givesemaphore() resides in user-space
* 2. The address of the user space mm_givesemaphore() is provided in
* user_map.h
* 3. The user-space mm_semaphore() is callable from kernel-space.
*
************************************************************************/
void kmm_givesemaphore(void)
{
KGIVESEMAPHORE();
}
#endif /* CONFIG_NUTTX_KERNEL */
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