nuttx/mm/umm_heap/umm_initialize.c
Gregory Nutt 59cc4a7a7b Protected mode: Redesign how the user space heap is accessed from the kernel code. It used to call memory management functions in user space via function pointers in the userspace interface. That is inefficient because the first thing that those memory management functions do is to trap back into the kernel to get the current PID. Worse, that operation can be fatal is certain fragile situations such as when a task is exitting.
The solution is to remove all of the memory management function calls from the interface.  Instead, the interface exports the userspace heap structure and then kernel size implementations of those memory management functions will operate on the userspace heap structure.  This avoids the unnecessary system calls and, more importantly, failures do to freeing memory when a test exits.
2015-07-10 08:37:02 -06:00

101 lines
4.1 KiB
C

/************************************************************************
* mm/umm_heap/umm_initialize.c
*
* Copyright (C) 2013-2015 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 <assert.h>
#include <nuttx/mm/mm.h>
#include "umm_heap/umm_heap.h"
/************************************************************************
* Public Functions
************************************************************************/
/************************************************************************
* Name: umm_initialize
*
* Description:
* This is a simple wrapper for the mm_initialize() function. This
* function will initialize the user heap.
*
* CONFIG_BUILD_FLAT:
* There is only kernel mode "blob" containing both containing both
* kernel and application code. There is only one heap that use is
* used by both the kernel and application logic.
*
* In this configuration, this function is called early in os_start()
* to initialize the common heap.
*
* CONFIG_BUILD_PROTECTED
* In this configuration, there are two "blobs", one containing
* protected kernel logic and one containing unprotected application
* logic. Depending upon the setting of CONFIG_MM_KERNEL_HEAP there
* may be only a signal shared heap, much as with CONFIG_BUILD_FLAT.
* Or there may be separate protected/kernel and unprotected/user
* heaps.
*
* In either case, this function is still called early in os_start()
* to initialize the user heap.
*
* CONFIG_BUILD_KERNEL
* In this configuration there are multiple user heaps, one for each
* user process. Furthermore, each heap is initially empty; memory
* is added to each heap dynamically via sbrk(). The heap data
* structure was set to zero when the address environment was created.
* Otherwise, the heap is uninitialized.
*
* This function is not called at all. Rather, this function is called
* when each user process is created before the first allocation is made.
*
* Parameters:
* heap_start - Address of the beginning of the (initial) memory region
* heap_size - The size (in bytes) if the (initial) memory region.
*
* Return Value:
* None
*
************************************************************************/
void umm_initialize(FAR void *heap_start, size_t heap_size)
{
mm_initialize(USR_HEAP, heap_start, heap_size);
}