105 lines
4.3 KiB
C
105 lines
4.3 KiB
C
/****************************************************************************
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* mm/umm_heap/umm_sbrk.c
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*
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* Copyright (C) 2014 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 <unistd.h>
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#include <nuttx/mm.h>
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#include <nuttx/addrenv.h>
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#include <nuttx/pgalloc.h>
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#if defined(CONFIG_BUILD_KERNEL)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* In the kernel build, there a multiple user heaps; one for each task
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* group. In this build configuration, the user heap structure lies
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* in a reserved region at the beginning of the .bss/.data address
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* space (CONFIG_ARCH_DATA_VBASE). The size of that region is given by
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* ARCH_DATA_RESERVE_SIZE
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*/
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#define USR_HEAP (&ARCH_DATA_RESERVE->ar_usrheap)
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: sbrk
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*
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* Description:
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* The sbrk() function is used to change the amount of space allocated
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* for the calling process. The change is made by resetting the process'
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* break value and allocating the appropriate amount of space. The amount
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* of allocated space increases as the break value increases.
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*
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* The sbrk() function adds 'incr' bytes to the break value and changes
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* the allocated space accordingly. If incr is negative, the amount of
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* allocated space is decreased by incr bytes. The current value of the
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* program break is returned by sbrk(0).
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*
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* Input Parameters:
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* incr - Specifies the number of bytes to add or to remove from the
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* space allocated for the process.
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*
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* Returned Value:
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* Upon successful completion, sbrk() returns the prior break value.
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* Otherwise, it returns (void *)-1 and sets errno to indicate the
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* error:
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*
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* ENOMEM - The requested change would allocate more space than
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* allowed under system limits.
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* EAGAIN - The total amount of system memory available for allocation
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* to this process is temporarily insufficient. This may occur even
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* though the space requested was less than the maximum data segment
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* size.
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*
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****************************************************************************/
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FAR void *sbrk(intptr_t incr)
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{
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return mm_sbrk(USR_HEAP, incr, CONFIG_ARCH_HEAP_NPAGES << MM_PGSHIFT);
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}
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#endif /* CONFIG_BUILD_KERNEL */
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