Line data    Source code

       1             : /* Get previous frame state for an existing frame state.
       2             :    Copyright (C) 2016 The Qt Company Ltd.
       3             :    This file is part of elfutils.
       4             : 
       5             :    This file is free software; you can redistribute it and/or modify
       6             :    it under the terms of either
       7             : 
       8             :      * the GNU Lesser General Public License as published by the Free
       9             :        Software Foundation; either version 3 of the License, or (at
      10             :        your option) any later version
      11             : 
      12             :    or
      13             : 
      14             :      * the GNU General Public License as published by the Free
      15             :        Software Foundation; either version 2 of the License, or (at
      16             :        your option) any later version
      17             : 
      18             :    or both in parallel, as here.
      19             : 
      20             :    elfutils is distributed in the hope that it will be useful, but
      21             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23             :    General Public License for more details.
      24             : 
      25             :    You should have received copies of the GNU General Public License and
      26             :    the GNU Lesser General Public License along with this program.  If
      27             :    not, see <http://www.gnu.org/licenses/>.  */
      28             : 
      29             : #ifdef HAVE_CONFIG_H
      30             : # include <config.h>
      31             : #endif
      32             : 
      33             : #define BACKEND aarch64_
      34             : #define FP_REG 29
      35             : #define LR_REG 30
      36             : #define SP_REG 31
      37             : #define FP_OFFSET 0
      38             : #define LR_OFFSET 8
      39             : #define SP_OFFSET 16
      40             : 
      41             : #include "libebl_CPU.h"
      42             : 
      43             : /* There was no CFI. Maybe we happen to have a frame pointer and can unwind from that?  */
      44             : 
      45             : bool
      46          13 : EBLHOOK(unwind) (Ebl *ebl __attribute__ ((unused)), Dwarf_Addr pc __attribute__ ((unused)),
      47             :                  ebl_tid_registers_t *setfunc, ebl_tid_registers_get_t *getfunc,
      48             :                  ebl_pid_memory_read_t *readfunc, void *arg,
      49             :                  bool *signal_framep __attribute__ ((unused)))
      50             : {
      51          13 :   Dwarf_Word fp, lr, sp;
      52             : 
      53          13 :   if (!getfunc(LR_REG, 1, &lr, arg))
      54             :     return false;
      55             : 
      56          13 :   if (lr == 0 || !setfunc(-1, 1, &lr, arg))
      57           2 :     return false;
      58             : 
      59          11 :   if (!getfunc(FP_REG, 1, &fp, arg))
      60           0 :     fp = 0;
      61             : 
      62          11 :   if (!getfunc(SP_REG, 1, &sp, arg))
      63           0 :     sp = 0;
      64             : 
      65          11 :   Dwarf_Word newLr, newFp, newSp;
      66             : 
      67          11 :   if (!readfunc(fp + LR_OFFSET, &newLr, arg))
      68           3 :     newLr = 0;
      69             : 
      70          11 :   if (!readfunc(fp + FP_OFFSET, &newFp, arg))
      71           3 :     newFp = 0;
      72             : 
      73          11 :   newSp = fp + SP_OFFSET;
      74             : 
      75             :   // These are not fatal if they don't work. They will just prevent unwinding at the next frame.
      76          11 :   setfunc(LR_REG, 1, &newLr, arg);
      77          11 :   setfunc(FP_REG, 1, &newFp, arg);
      78          11 :   setfunc(SP_REG, 1, &newSp, arg);
      79             : 
      80             :   // If the fp is invalid, we might still have a valid lr.
      81             :   // But if the fp is valid, then the stack should be moving in the right direction.
      82          13 :   return fp == 0 || newSp > sp;
      83             : }