rockbox/lib/unwarminder/backtrace.c
Amaury Pouly d4674ed3b7 arm: implement safe reads by intercepting the data abort handler.
Implement functions to read from a memory location and indicate
failure in case this is not possible. Since we do not have a MMU,
intercept the data abort handler and simply return when the abort
comes from the safe read routines.

Change-Id: I08f2e59898dcac893319a8150d4cf626f3adabbd
Reviewed-on: http://gerrit.rockbox.org/207
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>
2012-04-06 13:48:09 +02:00

122 lines
4 KiB
C

/***************************************************************************
* ARM Stack Unwinder, Michael.McTernan.2001@cs.bris.ac.uk
*
* This program is PUBLIC DOMAIN.
* This means that there is no copyright and anyone is able to take a copy
* for free and use it as they wish, with or without modifications, and in
* any context, commercially or otherwise. The only limitation is that I
* don't guarantee that the software is fit for any purpose or accept any
* liability for it's use or misuse - this software is without warranty.
***************************************************************************
* File Description: Unwinder client that reads local memory.
* This client reads from local memory and is designed to run on target
* along with the unwinder. Memory read requests are implemented by
* casting a point to read the memory directly, although checks for
* alignment should probably also be made if this is to be used in
* production code, as otherwise the ARM may return the memory in a
* rotated/rolled format, or the MMU may generate an alignment exception
* if present and so configured.
**************************************************************************/
/***************************************************************************
* Includes
***************************************************************************/
#include "backtrace.h"
#include "safe_read.h"
/***************************************************************************
* Prototypes
***************************************************************************/
static Boolean CliReport(void *data, Int32 address);
static Boolean CliReadW(Int32 a, Int32 *v);
static Boolean CliReadH(Int32 a, Int16 *v);
static Boolean CliReadB(Int32 a, Int8 *v);
/***************************************************************************
* Variables
***************************************************************************/
/* Table of function pointers for passing to the unwinder */
const UnwindCallbacks cliCallbacks =
{
CliReport,
CliReadW,
CliReadH,
CliReadB
#if defined(UNW_DEBUG)
,printf
#endif
};
/***************************************************************************
* Callbacks
***************************************************************************/
/***************************************************************************
*
* Function: CliReport
*
* Parameters: data - Pointer to data passed to UnwindStart()
* address - The return address of a stack frame.
*
* Returns: TRUE if unwinding should continue, otherwise FALSE to
* indicate that unwinding should stop.
*
* Description: This function is called from the unwinder each time a stack
* frame has been unwound. The LSB of address indicates if
* the processor is in ARM mode (LSB clear) or Thumb (LSB
* set).
*
***************************************************************************/
static Boolean CliReport(void *data, Int32 address)
{
/* CliStack *s = (CliStack *)data; */
unsigned *line = (unsigned *)data;
lcd_putsf(0, (*line)++, " %c: 0x%08x",
(address & 0x1) ? 'T' : 'A',
address & (~0x1));
lcd_update();
return TRUE;
}
static Boolean CliReadW(const Int32 a, Int32 *v)
{
return safe_read32((uint32_t *)a, (uint32_t *)v);
}
static Boolean CliReadH(const Int32 a, Int16 *v)
{
return safe_read16((void *)a, (uint16_t *)v);
}
static Boolean CliReadB(const Int32 a, Int8 *v)
{
return safe_read8((void *)a, (uint8_t *)v);
}
Boolean CliInvalidateW(const Int32 a)
{
*(Int32 *)a = 0xdeadbeef;
return TRUE;
}
void backtrace(int pcAddr, int spAddr, unsigned *line)
{
UnwResult r;
lcd_putsf(0, (*line)++, "bt pc: 0x%08x, sp: 0x%08x", pcAddr, spAddr);
lcd_update();
r = UnwindStart(pcAddr, spAddr, &cliCallbacks, (void *)line);
lcd_puts(0, (*line)++, "bt end");
lcd_update();
}
/* END OF FILE */