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/****************************************************************************
* arch/arm/src/arm/up_dataabort.c
*
* Copyright (C) 2007-2011 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/irq.h>
#include "os_internal.h"
#include "up_internal.h"
#ifdef CONFIG_PAGING
# include <nuttx/page.h>
# include "arm.h"
#endif
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Output debug info if stack dump is selected -- even if
* debug is not selected.
*/
#ifdef CONFIG_ARCH_STACKDUMP
# undef lldbg
# define lldbg lib_lowprintf
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_dataabort
*
* Input parameters:
* regs - The standard, ARM register save array.
*
* If CONFIG_PAGING is selected in the NuttX configuration file, then these
* additional input values are expected:
*
* far - Fault address register. On a data abort, the ARM MMU places the
* miss virtual address (MVA) into the FAR register. This is the address
* of the data which, when accessed, caused the fault.
* fsr - Fault status register. On a data a abort, the ARM MMU places an
* encoded four-bit value, the fault status, along with the four-bit
* encoded domain number, in the data FSR
*
* Description:
* This is the data abort exception handler. The ARM data abort exception
* occurs when a memory fault is detected during a data transfer.
*
****************************************************************************/
#ifdef CONFIG_PAGING
void up_dataabort(uint32_t *regs, uint32_t far, uint32_t fsr)
{
FAR _TCB *tcb = (FAR _TCB *)g_readytorun.head;
#ifdef CONFIG_PAGING
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;
#endif
current_regs = regs;
#ifdef CONFIG_PAGING
/* In the NuttX on-demand paging implementation, only the read-only, .text
* section is paged. However, the ARM compiler generated PC-relative data
* fetches from within the .text sections. Also, it is customary to locate
* read-only data (.rodata) within the same section as .text so that it
* does not require copying to RAM. Misses in either of these case should
* cause a data abort.
*
* We are only interested in data aborts due to page translations faults.
* Sections should already be in place and permissions should already be
* be set correctly (to read-only) so any other data abort reason is a
* fatal error.
*/
pglldbg("FSR: %08x FAR: %08x\n", fsr, far);
if ((fsr & FSR_MASK) != FSR_PAGE)
{
goto segfault;
}
/* Check the (virtual) address of data that caused the data abort. When
* the exception occurred, this address was provided in the FAR register.
* (It has not yet been saved in the register context save area).
*/
pgllvdbg("VBASE: %08x VEND: %08x\n", PG_PAGED_VBASE, PG_PAGED_VEND);
if (far < PG_PAGED_VBASE || far >= PG_PAGED_VEND)
{
goto segfault;
}
/* Save the offending data address as the fault address in the TCB of
* the currently task. This fault address is also used by the prefetch
* abort handling; this will allow common paging logic for both
* prefetch and data aborts.
*/
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;
return;
segfault:
#endif
lldbg("Data abort. PC: %08x FAR: %08x FSR: %08x\n", regs[REG_PC], far, fsr);
PANIC(OSERR_ERREXCEPTION);
}
#else /* CONFIG_PAGING */
void up_dataabort(uint32_t *regs)
{
/* 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 diagnost debug information. */
lldbg("Data abort. PC: %08x\n", regs[REG_PC]);
PANIC(OSERR_ERREXCEPTION);
}
#endif /* CONFIG_PAGING */
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