458ff380e5
User can ask for specific granules to be allocated. This is useful for one thing only: when mmap() is called for a specific vaddr. The parameter itself is non-sensical, this is just to satisfy the POSIX standard.
122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/****************************************************************************
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* mm/mm_gran/mm_granmark.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/gran.h>
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#include "mm_gran/mm_gran.h"
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#ifdef CONFIG_GRAN
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: gran_mark_allocated
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*
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* Description:
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* Mark a range of granules as allocated.
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*
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* Input Parameters:
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* priv - The granule heap state structure.
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* alloc - The address of the allocation.
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* ngranules - The number of granules allocated
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*
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* Returned Value:
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* On success, a non-NULL pointer to the allocated memory is returned;
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* NULL is returned on failure.
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*
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****************************************************************************/
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FAR void *gran_mark_allocated(FAR struct gran_s *priv, uintptr_t alloc,
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unsigned int ngranules)
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{
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unsigned int granno;
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unsigned int gatidx;
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unsigned int gatbit;
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unsigned int avail;
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uint32_t gatmask;
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/* Determine the granule number of the allocation */
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granno = (alloc - priv->heapstart) >> priv->log2gran;
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/* Determine the GAT table index associated with the allocation */
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gatidx = granno >> 5;
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gatbit = granno & 31;
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/* Mark bits in the GAT entry or entries */
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avail = 32 - gatbit;
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if (ngranules > avail)
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{
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uint32_t gatmask2;
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gatmask = 0xffffffff << gatbit;
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ngranules -= avail;
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gatmask2 = 0xffffffff >> (32 - ngranules);
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/* Check that the area is free, from both mask words */
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if (((priv->gat[gatidx] & gatmask) != 0) ||
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((priv->gat[gatidx + 1] & gatmask2) != 0))
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{
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return NULL;
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}
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/* Mark bits in the first and second GAT entry */
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priv->gat[gatidx] |= gatmask;
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priv->gat[gatidx + 1] |= gatmask2;
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}
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/* Handle the case where where all of the granules come from one entry */
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else
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{
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gatmask = 0xffffffff >> (32 - ngranules);
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gatmask <<= gatbit;
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/* Check that the area is free */
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if ((priv->gat[gatidx] & gatmask) != 0)
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{
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return NULL;
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}
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/* Mark bits in a single GAT entry */
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priv->gat[gatidx] |= gatmask;
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}
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return (FAR void *)alloc;
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}
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#endif /* CONFIG_GRAN */
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