LCOV - code coverage report
Current view: top level - backends - ppc64_unwind.c (source / functions) Hit Total Coverage
Test: elfutils-0.178 Lines: 12 15 80.0 %
Date: 2019-11-26 23:55:16 Functions: 1 1 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /* Get previous frame state for an existing frame state.
       2             :    Copyright (C) 2017 Red Hat, Inc.
       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 ppc64_
      34             : 
      35             : #define LR_REG 65 /* Not 108, see ppc_dwarf_to_regno.  */
      36             : #define SP_REG  1
      37             : 
      38             : #define LR_OFFSET 16
      39             : 
      40             : #include "libebl_CPU.h"
      41             : 
      42             : /* Simplistic fallback frame unwinder. SP points to the backchain (contains
      43             :    address of previous stack pointer). At SP offset 16 is the LR save area
      44             :    (contains the value of the previous LR).  */
      45             : 
      46             : bool
      47          10 : EBLHOOK(unwind) (Ebl *ebl __attribute__ ((unused)),
      48             :                  Dwarf_Addr pc __attribute__ ((unused)),
      49             :                  ebl_tid_registers_t *setfunc, ebl_tid_registers_get_t *getfunc,
      50             :                  ebl_pid_memory_read_t *readfunc, void *arg,
      51             :                  bool *signal_framep __attribute__ ((unused)))
      52             : {
      53          10 :   Dwarf_Word sp, newSp, lr, newLr;
      54             : 
      55             :   /* Stack pointer points to the backchain which contains the previous sp.  */
      56          10 :   if (! getfunc (SP_REG, 1, &sp, arg))
      57           0 :     sp = 0;
      58             : 
      59             :   /* Link register contains previous program counter.  */
      60          10 :   if (! getfunc (LR_REG, 1, &lr, arg)
      61          10 :       || lr == 0
      62           8 :       || ! setfunc (-1, 1, &lr, arg))
      63           2 :     return false;
      64             : 
      65           8 :   if (! readfunc(sp, &newSp, arg))
      66           0 :     newSp = 0;
      67             : 
      68           8 :   if (! readfunc(newSp + LR_OFFSET, &newLr, arg))
      69           0 :     newLr = 0;
      70             : 
      71           8 :   setfunc(SP_REG, 1, &newSp, arg);
      72           8 :   setfunc(LR_REG, 1, &newLr, arg);
      73             : 
      74             :   /* Sanity check the stack grows down.  */
      75           8 :   return newSp > sp;
      76             : }

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