nuttx/arch/arm/src/armv7-a/arm_prefetchabort.c

/****************************************************************************
 *  arch/arm/src/armv7-a/arm_prefetchabort.c
 *
 *   Copyright (C) 2013, 2016 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * 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
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 * 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/irq.h>
#ifdef CONFIG_PAGING
#  include <nuttx/page.h>
#endif

#include "sched/sched.h"
#include "up_internal.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: arm_prefetchabort
 *
 * Description;
 *   This is the prefetch abort exception handler. The ARM prefetch abort
 *   exception occurs when a memory fault is detected during an an
 *   instruction fetch.
 *
 ****************************************************************************/

#ifdef CONFIG_PAGING

uint32_t *arm_prefetchabort(uint32_t *regs, uint32_t ifar, uint32_t ifsr)
{
   uint32_t *savestate;

  /* Save the saved processor context in CURRENT_REGS where it can be accessed
   * for register dumps and possibly context switching.
   */

  savestate    = (uint32_t *)CURRENT_REGS;
  CURRENT_REGS = regs;

  /* Get the (virtual) address of instruction that caused the prefetch abort.
   * When the exception occurred, this address was provided in the lr register
   * and this value was saved in the context save area as the PC at the
   * REG_R15 index.
   *
   * Check to see if this miss address is within the configured range of
   * virtual addresses.
   */

  pginfo("VADDR: %08x VBASE: %08x VEND: %08x\n",
         regs[REG_PC], PG_PAGED_VBASE, PG_PAGED_VEND);

  if (regs[REG_R15] >= PG_PAGED_VBASE && regs[REG_R15] < PG_PAGED_VEND)
    {
      /* Save the offending PC as the fault address in the TCB of the currently
       * executing task.  This value is, of course, already known in regs[REG_R15],
       * but saving it in this location will allow common paging logic for both
       * prefetch and data aborts.
       */

      struct tcb_s *tcb = this_task();
      tcb->xcp.far  = regs[REG_R15];

      /* Call pg_miss() to schedule the page fill.  A consequences of this
       * call are:
       *
       * (1) The currently executing task will be blocked and saved on
       *     on the g_waitingforfill task list.
       * (2) An interrupt-level context switch will occur so that when
       *     this function returns, it will return to a different task,
       *     most likely the page fill worker thread.
       * (3) The page fill worker task has been signalled and should
       *     execute immediately when we return from this exception.
       */

      pg_miss();

      /* Restore the previous value of CURRENT_REGS.  NULL would indicate that
       * we are no longer in an interrupt handler.  It will be non-NULL if we
       * are returning from a nested interrupt.
       */

      CURRENT_REGS = savestate;
    }
  else
    {
      _alert("Prefetch abort. PC: %08x IFAR: %08x IFSR: %08x\n",
            regs[REG_PC], ifar, ifsr);
      PANIC();
    }

  return regs;
}

#else /* CONFIG_PAGING */

uint32_t *arm_prefetchabort(uint32_t *regs, uint32_t ifar, uint32_t ifsr)
{
  /* Save the saved processor context in CURRENT_REGS where it can be accessed
   * for register dumps and possibly context switching.
   */

  CURRENT_REGS = regs;

  /* Crash -- possibly showing diagnostic debug information. */

  _alert("Prefetch abort. PC: %08x IFAR: %08x IFSR: %08x\n",
        regs[REG_PC], ifar, ifsr);
  PANIC();
  return regs; /* To keep the compiler happy */
}

#endif /* CONFIG_PAGING */