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/****************************************************************************
* arch/arm/src/arm/up_checkmapping.c
* Check if the current task's fault address has been mapped into the virtual
* address space.
*
* Copyright (C) 2010 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <debug.h>
#include <nuttx/sched.h>
#include <nuttx/page.h>
#include "up_internal.h"
#ifdef CONFIG_PAGING
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_checkmapping()
*
* Description:
* The function up_checkmapping() returns an indication if the page fill
* still needs to performed or not. In certain conditions, the page fault
* may occur on several threads and be queued multiple times. This function
* will prevent the same page from be filled multiple times.
*
* Input Parameters:
* tcb - A reference to the task control block of the task that we believe
* needs to have a page fill. Architecture-specific logic can
* retrieve page fault information from the architecture-specific
* context information in this TCB and can consult processor resources
* (page tables or TLBs or ???) to determine if the fill still needs
* to be performed or not.
*
* Returned Value:
* This function will return true if the mapping is in place and false
* if the mapping is still needed. Errors encountered should be
* interpreted as fatal.
*
* Assumptions:
* - This function is called from the normal tasking context (but with
* interrupts disabled). The implementation must take whatever actions
* are necessary to assure that the operation is safe within this
* context.
*
****************************************************************************/
bool up_checkmapping(FAR _TCB *tcb)
{
uintptr_t vaddr;
uint32_t *pte;
/* Since interrupts are disabled, we don't need to anything special. */
DEBUGASSERT(tcb);
/* Get the virtual address that caused the fault */
vaddr = tcb->xcp.far;
DEBUGASSERT(vaddr >= PG_PAGED_VBASE && vaddr < PG_PAGED_VEND);
/* Get the PTE associated with this virtual address */
pte = up_va2pte(vaddr);
/* Return true if this virtual address is mapped. */
return (*pte != 0);
}
#endif /* CONFIG_PAGING */
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