152 lines
4.3 KiB
C
152 lines
4.3 KiB
C
/****************************************************************************
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* fs/mmap/fs_anonmap.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 <nuttx/kmalloc.h>
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#include <debug.h>
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: unmap_anonymous
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****************************************************************************/
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static int unmap_anonymous(FAR struct task_group_s *group,
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FAR struct mm_map_entry_s *entry,
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FAR void *start,
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size_t length)
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{
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FAR void *newaddr;
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off_t offset;
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bool kernel = entry->priv.i;
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int ret = OK;
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/* Get the offset from the beginning of the region and the actual number
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* of bytes to "unmap". All mappings must extend to the end of the region.
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* There is no support for freeing a block of memory but leaving a block of
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* memory at the end. This is a consequence of using kumm_realloc() to
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* simulate the unmapping.
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*/
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offset = (uintptr_t)start - (uintptr_t)entry->vaddr;
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if (offset + length < entry->length)
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{
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ferr("ERROR: Cannot umap without unmapping to the end\n");
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return -ENOSYS;
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}
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/* Okay.. the region is being unmapped to the end. Make sure the length
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* indicates that.
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*/
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length = entry->length - offset;
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/* Are we unmapping the entire region (offset == 0)? */
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if (length >= entry->length)
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{
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/* Free the region */
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if (kernel)
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{
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kmm_free(entry->vaddr);
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}
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else
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{
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kumm_free(entry->vaddr);
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}
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/* Then remove the mapping from the list */
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ret = mm_map_remove(get_group_mm(group), entry);
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}
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/* No.. We have been asked to "unmap' only a portion of the memory
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* (offset > 0).
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*/
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else
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{
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if (kernel)
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{
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newaddr = kmm_realloc(entry->vaddr, length);
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}
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else
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{
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newaddr = kumm_realloc(entry->vaddr, length);
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}
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DEBUGASSERT(newaddr == entry->vaddr);
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entry->vaddr = newaddr;
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entry->length = length;
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}
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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int map_anonymous(FAR struct mm_map_entry_s *entry, bool kernel)
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{
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int ret;
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/* REVISIT: Should reside outside of the heap. That is really the
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* only purpose of MAP_ANONYMOUS: To get non-heap memory. In KERNEL
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* build, this could be accomplished using pgalloc(), provided that
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* you had logic in place to assign a virtual address to the mapping.
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*/
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entry->vaddr = kernel ?
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kmm_zalloc(entry->length) : kumm_zalloc(entry->length);
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if (entry->vaddr == NULL)
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{
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ferr("ERROR: kumm_alloc() failed, enable DEBUG_MM for info!\n");
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return -ENOMEM;
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}
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entry->munmap = unmap_anonymous;
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entry->priv.i = kernel;
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ret = mm_map_add(entry);
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if (ret < 0)
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{
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if (kernel)
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{
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kmm_free(entry->vaddr);
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}
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else
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{
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kumm_free(entry->vaddr);
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}
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entry->vaddr = NULL;
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}
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return ret;
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}
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