96 lines
3.4 KiB
C
96 lines
3.4 KiB
C
/****************************************************************************
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* arch/arm/src/armv7-a/arm_checkmapping.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 <stdint.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/sched.h>
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#include <nuttx/page.h>
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#include "arm_internal.h"
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#ifdef CONFIG_PAGING
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: arm_checkmapping()
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*
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* Description:
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* The function arm_checkmapping() returns an indication if the page fill
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* still needs to performed or not. In certain conditions, the page fault
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* may occur on several threads and be queued multiple times. This function
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* will prevent the same page from be filled multiple times.
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*
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* Input Parameters:
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* tcb - A reference to the task control block of the task that we believe
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* needs to have a page fill. Architecture-specific logic can
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* retrieve page fault information from the architecture-specific
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* context information in this TCB and can consult processor
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* resources (page tables or TLBs or ???) to determine if the fill
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* still needs to be performed or not.
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*
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* Returned Value:
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* This function will return true if the mapping is in place and false
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* if the mapping is still needed. Errors encountered should be
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* interpreted as fatal.
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*
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* Assumptions:
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* - This function is called from the normal tasking context (but with
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* interrupts disabled). The implementation must take whatever actions
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* are necessary to assure that the operation is safe within this
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* context.
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*
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****************************************************************************/
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bool arm_checkmapping(FAR struct tcb_s *tcb)
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{
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uintptr_t vaddr;
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uint32_t *pte;
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/* Since interrupts are disabled, we don't need to anything special. */
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DEBUGASSERT(tcb);
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/* Get the virtual address that caused the fault */
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vaddr = tcb->xcp.far;
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DEBUGASSERT(vaddr >= PG_PAGED_VBASE && vaddr < PG_PAGED_VEND);
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/* Get the PTE associated with this virtual address */
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pte = arm_va2pte(vaddr);
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/* Return true if this virtual address is mapped. */
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return (*pte != 0);
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}
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#endif /* CONFIG_PAGING */
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