fccda0c08b
Signed-off-by: wangbowen6 <wangbowen6@xiaomi.com> Signed-off-by: YAMAMOTO Takashi <yamamoto@midokura.com>
238 lines
7.1 KiB
C
238 lines
7.1 KiB
C
/****************************************************************************
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* mm/mm_heap/mm_memalign.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <assert.h>
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#include <nuttx/mm/mm.h>
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#include "mm_heap/mm.h"
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#include "kasan/kasan.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: mm_memalign
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*
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* Description:
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* memalign requests more than enough space from malloc, finds a region
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* within that chunk that meets the alignment request and then frees any
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* leading or trailing space.
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*
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* The alignment argument must be a power of two. 8-byte alignment is
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* guaranteed by normal malloc calls.
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*
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****************************************************************************/
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FAR void *mm_memalign(FAR struct mm_heap_s *heap, size_t alignment,
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size_t size)
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{
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FAR struct mm_allocnode_s *node;
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size_t rawchunk;
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size_t alignedchunk;
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size_t mask = (size_t)(alignment - 1);
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size_t allocsize;
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size_t newsize;
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bool ret;
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/* Make sure that alignment is less than half max size_t */
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if (alignment >= (SIZE_MAX / 2))
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{
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return NULL;
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}
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/* Make sure that alignment is a power of 2 */
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if ((alignment & -alignment) != alignment)
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{
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return NULL;
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}
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/* If this requested alinement's less than or equal to the natural
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* alignment of malloc, then just let malloc do the work.
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*/
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if (alignment <= MM_MIN_CHUNK)
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{
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FAR void *ptr = mm_malloc(heap, size);
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DEBUGASSERT(ptr == NULL || ((uintptr_t)ptr) % alignment == 0);
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return ptr;
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}
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/* Adjust the size to account for (1) the size of the allocated node, (2)
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* to make sure that it is an even multiple of our granule size, and to
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* include the alignment amount.
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*
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* Notice that we increase the allocation size by twice the requested
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* alignment. We do this so that there will be at least two valid
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* alignment points within the allocated memory.
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*
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* NOTE: These are sizes given to malloc and not chunk sizes. They do
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* not include SIZEOF_MM_ALLOCNODE.
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*/
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newsize = MM_ALIGN_UP(size); /* Make multiples of our granule size */
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allocsize = newsize + 2 * alignment; /* Add double full alignment size */
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if ((newsize < size) || (allocsize < newsize))
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{
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/* Integer overflow */
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return NULL;
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}
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/* Then malloc that size */
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rawchunk = (size_t)mm_malloc(heap, allocsize);
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if (rawchunk == 0)
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{
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return NULL;
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}
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kasan_poison((FAR void *)rawchunk, mm_malloc_size((FAR void *)rawchunk));
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/* We need to hold the MM mutex while we muck with the chunks and
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* nodelist.
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*/
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ret = mm_lock(heap);
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DEBUGASSERT(ret);
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/* Get the node associated with the allocation and the next node after
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* the allocation.
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*/
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node = (FAR struct mm_allocnode_s *)(rawchunk - SIZEOF_MM_ALLOCNODE);
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/* Find the aligned subregion */
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alignedchunk = (rawchunk + mask) & ~mask;
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/* Check if there is free space at the beginning of the aligned chunk */
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if (alignedchunk != rawchunk)
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{
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FAR struct mm_allocnode_s *newnode;
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FAR struct mm_allocnode_s *next;
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size_t precedingsize;
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/* Get the node the next node after the allocation. */
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next = (FAR struct mm_allocnode_s *)((FAR char *)node + node->size);
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/* Make sure that there is space to convert the preceding
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* mm_allocnode_s into an mm_freenode_s. I think that this should
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* always be true
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*/
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DEBUGASSERT(alignedchunk >= rawchunk + 8);
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newnode = (FAR struct mm_allocnode_s *)
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(alignedchunk - SIZEOF_MM_ALLOCNODE);
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/* Preceding size is full size of the new 'node,' including
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* SIZEOF_MM_ALLOCNODE
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*/
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precedingsize = (size_t)newnode - (size_t)node;
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/* If we were unlucky, then the alignedchunk can lie in such a position
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* that precedingsize < SIZEOF_NODE_FREENODE. We can't let that happen
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* because we are going to cast 'node' to struct mm_freenode_s below.
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* This is why we allocated memory large enough to support two
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* alignment points. In this case, we will simply use the second
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* alignment point.
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*/
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if (precedingsize < SIZEOF_MM_FREENODE)
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{
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alignedchunk += alignment;
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newnode = (FAR struct mm_allocnode_s *)
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(alignedchunk - SIZEOF_MM_ALLOCNODE);
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precedingsize = (size_t)newnode - (size_t)node;
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}
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/* Set up the size of the new node */
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newnode->size = (size_t)next - (size_t)newnode;
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newnode->preceding = precedingsize | MM_ALLOC_BIT;
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/* Reduce the size of the original chunk and mark it not allocated, */
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node->size = precedingsize;
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node->preceding &= ~MM_MASK_BIT;
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/* Fix the preceding size of the next node */
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next->preceding = newnode->size | (next->preceding & MM_ALLOC_BIT);
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/* Convert the newnode chunk size back into malloc-compatible size by
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* subtracting the header size SIZEOF_MM_ALLOCNODE.
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*/
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allocsize = newnode->size - SIZEOF_MM_ALLOCNODE;
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/* Add the original, newly freed node to the free nodelist */
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mm_addfreechunk(heap, (FAR struct mm_freenode_s *)node);
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/* Replace the original node with the newlay realloaced,
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* aligned node
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*/
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node = newnode;
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}
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/* Check if there is free space at the end of the aligned chunk. Convert
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* malloc-compatible chunk size to include SIZEOF_MM_ALLOCNODE as needed
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* for mm_shrinkchunk.
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*/
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size = MM_ALIGN_UP(size + SIZEOF_MM_ALLOCNODE);
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if (allocsize > size)
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{
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/* Shrink the chunk by that much -- remember, mm_shrinkchunk wants
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* internal chunk sizes that include SIZEOF_MM_ALLOCNODE.
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*/
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mm_shrinkchunk(heap, node, size);
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}
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mm_unlock(heap);
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MM_ADD_BACKTRACE(heap, node);
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kasan_unpoison((FAR void *)alignedchunk,
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mm_malloc_size((FAR void *)alignedchunk));
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DEBUGASSERT(alignedchunk % alignment == 0);
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return (FAR void *)alignedchunk;
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}
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