gdb/gdbserver/linux-arm-low.c

   1 /* GNU/Linux/ARM specific low level interface, for the remote server for GDB.
   2    Copyright 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "server.h"
  23 #include "linux-low.h"
  24
  25 #ifdef HAVE_SYS_REG_H
  26 #include <sys/reg.h>
  27 #endif
  28
  29 #define arm_num_regs 26
  30
  31 static int arm_regmap[] = {
  32   0, 4, 8, 12, 16, 20, 24, 28,
  33   32, 36, 40, 44, 48, 52, 56, 60,
  34   -1, -1, -1, -1, -1, -1, -1, -1, -1,
  35   64
  36 };
  37
  38 static int
  39 arm_cannot_store_register (int regno)
  40 {
  41   return (regno >= arm_num_regs);
  42 }
  43
  44 static int
  45 arm_cannot_fetch_register (int regno)
  46 {
  47   return (regno >= arm_num_regs);
  48 }
  49
  50 extern int debug_threads;
  51
  52 static CORE_ADDR
  53 arm_get_pc ()
  54 {
  55   unsigned long pc;
  56   collect_register_by_name ("pc", &pc);
  57   if (debug_threads)
  58     fprintf (stderr, "stop pc is %08lx\n", pc);
  59   return pc;
  60 }
  61
  62 static void
  63 arm_set_pc (CORE_ADDR pc)
  64 {
  65   unsigned long newpc = pc;
  66   supply_register_by_name ("pc", &newpc);
  67 }
  68
  69 /* Correct in either endianness.  We do not support Thumb yet.  */
  70 static const unsigned long arm_breakpoint = 0xef9f0001;
  71 #define arm_breakpoint_len 4
  72
  73 /* For new EABI binaries.  We recognize it regardless of which ABI
  74    is used for gdbserver, so single threaded debugging should work
  75    OK, but for multi-threaded debugging we only insert the current
  76    ABI's breakpoint instruction.  For now at least.  */
  77 static const unsigned long arm_eabi_breakpoint = 0xe7f001f0;
  78
  79 static int
  80 arm_breakpoint_at (CORE_ADDR where)
  81 {
  82   unsigned long insn;
  83
  84   (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
  85   if (insn == arm_breakpoint)
  86     return 1;
  87
  88   if (insn == arm_eabi_breakpoint)
  89     return 1;
  90
  91   /* If necessary, recognize more trap instructions here.  GDB only uses the
  92      two.  */
  93
  94   return 0;
  95 }
  96
  97 /* We only place breakpoints in empty marker functions, and thread locking
  98    is outside of the function.  So rather than importing software single-step,
  99    we can just run until exit.  */
 100 static CORE_ADDR
 101 arm_reinsert_addr ()
 102 {
 103   unsigned long pc;
 104   collect_register_by_name ("lr", &pc);
 105   return pc;
 106 }
 107
 108 struct linux_target_ops the_low_target = {
 109   arm_num_regs,
 110   arm_regmap,
 111   arm_cannot_fetch_register,
 112   arm_cannot_store_register,
 113   arm_get_pc,
 114   arm_set_pc,
 115 #ifndef __ARM_EABI__
 116   (const unsigned char *) &arm_breakpoint,
 117 #else
 118   (const unsigned char *) &arm_eabi_breakpoint,
 119 #endif
 120   arm_breakpoint_len,
 121   arm_reinsert_addr,
 122   0,
 123   arm_breakpoint_at,
 124 };