119 lines
3.6 KiB
C
119 lines
3.6 KiB
C
/****************************************************************************
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* mm/mm_heap/mm_lock.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 <unistd.h>
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#include <errno.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/mm/mm.h>
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#include "mm_heap/mm.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_lock
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*
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* Description:
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* Take the MM mutex. This may be called from the OS in certain conditions
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* when it is impossible to wait on a mutex:
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* 1.The idle process performs the memory corruption check.
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* 2.The task/thread free the memory in the exiting process.
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*
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* Input Parameters:
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* heap - heap instance want to take mutex
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*
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* Returned Value:
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* 0 if the lock can be taken, otherwise negative errno.
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*
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****************************************************************************/
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int mm_lock(FAR struct mm_heap_s *heap)
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{
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#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__)
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/* Check current environment */
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if (up_interrupt_context())
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{
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#if !defined(CONFIG_SMP)
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/* Check the mutex value, if held by someone, then return false.
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* Or, touch the heap internal data directly.
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*/
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return nxmutex_is_locked(&heap->mm_lock) ? -EAGAIN : 0;
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#else
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/* Can't take mutex in SMP interrupt handler */
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return -EAGAIN;
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#endif
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}
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else
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#endif
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/* gettid() returns the task ID of the task at the head of the ready-to-
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* run task list. mm_lock() may be called during context
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* switches. There are certain situations during context switching when
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* the OS data structures are in flux and then can't be freed immediately
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* (e.g. the running thread stack).
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*
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* This is handled by gettid() to return the special value -ESRCH to
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* indicate this special situation.
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*/
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if (gettid() < 0)
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{
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return -ESRCH;
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}
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else
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{
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return nxmutex_lock(&heap->mm_lock);
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}
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}
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/****************************************************************************
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* Name: mm_unlock
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*
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* Description:
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* Release the MM mutex when it is not longer needed.
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*
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****************************************************************************/
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void mm_unlock(FAR struct mm_heap_s *heap)
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{
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#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__)
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if (up_interrupt_context())
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{
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return;
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}
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#endif
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DEBUGVERIFY(nxmutex_unlock(&heap->mm_lock));
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}
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