gdb/gdbserver/linux-arm-low.c

   1 /* GNU/Linux/ARM specific low level interface, for the remote server for GDB.
   2    Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   3    2006, 2007 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., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "server.h"
  23 #include "linux-low.h"
  24
  25 #include <sys/ptrace.h>
  26
  27 #include "gdb_proc_service.h"
  28
  29 #ifndef PTRACE_GET_THREAD_AREA
  30 #define PTRACE_GET_THREAD_AREA 22
  31 #endif
  32
  33 #ifndef PTRACE_GETWMMXREGS
  34 # define PTRACE_GETWMMXREGS 18
  35 # define PTRACE_SETWMMXREGS 19
  36 #endif
  37
  38 #ifdef HAVE_SYS_REG_H
  39 #include <sys/reg.h>
  40 #endif
  41
  42 #define arm_num_regs 26
  43
  44 static int arm_regmap[] = {
  45   0, 4, 8, 12, 16, 20, 24, 28,
  46   32, 36, 40, 44, 48, 52, 56, 60,
  47   -1, -1, -1, -1, -1, -1, -1, -1, -1,
  48   64
  49 };
  50
  51 static int
  52 arm_cannot_store_register (int regno)
  53 {
  54   return (regno >= arm_num_regs);
  55 }
  56
  57 static int
  58 arm_cannot_fetch_register (int regno)
  59 {
  60   return (regno >= arm_num_regs);
  61 }
  62
  63 static void
  64 arm_fill_gregset (void *buf)
  65 {
  66   int i;
  67
  68   for (i = 0; i < arm_num_regs; i++)
  69     if (arm_regmap[i] != -1)
  70       collect_register (i, ((char *) buf) + arm_regmap[i]);
  71 }
  72
  73 static void
  74 arm_store_gregset (const void *buf)
  75 {
  76   int i;
  77   char zerobuf[8];
  78
  79   memset (zerobuf, 0, 8);
  80   for (i = 0; i < arm_num_regs; i++)
  81     if (arm_regmap[i] != -1)
  82       supply_register (i, ((char *) buf) + arm_regmap[i]);
  83     else
  84       supply_register (i, zerobuf);
  85 }
  86
  87 #ifdef __IWMMXT__
  88
  89 static void
  90 arm_fill_wmmxregset (void *buf)
  91 {
  92   int i;
  93
  94   for (i = 0; i < 16; i++)
  95     collect_register (arm_num_regs + i, (char *) buf + i * 8);
  96
  97   /* We only have access to wcssf, wcasf, and wcgr0-wcgr3.  */
  98   for (i = 0; i < 6; i++)
  99     collect_register (arm_num_regs + i + 16, (char *) buf + 16 * 8 + i * 4);
 100 }
 101
 102 static void
 103 arm_store_wmmxregset (const void *buf)
 104 {
 105   int i;
 106
 107   for (i = 0; i < 16; i++)
 108     supply_register (arm_num_regs + i, (char *) buf + i * 8);
 109
 110   /* We only have access to wcssf, wcasf, and wcgr0-wcgr3.  */
 111   for (i = 0; i < 6; i++)
 112     supply_register (arm_num_regs + i + 16, (char *) buf + 16 * 8 + i * 4);
 113 }
 114
 115 #endif /* __IWMMXT__ */
 116
 117 extern int debug_threads;
 118
 119 static CORE_ADDR
 120 arm_get_pc ()
 121 {
 122   unsigned long pc;
 123   collect_register_by_name ("pc", &pc);
 124   if (debug_threads)
 125     fprintf (stderr, "stop pc is %08lx\n", pc);
 126   return pc;
 127 }
 128
 129 static void
 130 arm_set_pc (CORE_ADDR pc)
 131 {
 132   unsigned long newpc = pc;
 133   supply_register_by_name ("pc", &newpc);
 134 }
 135
 136 /* Correct in either endianness.  We do not support Thumb yet.  */
 137 static const unsigned long arm_breakpoint = 0xef9f0001;
 138 #define arm_breakpoint_len 4
 139
 140 /* For new EABI binaries.  We recognize it regardless of which ABI
 141    is used for gdbserver, so single threaded debugging should work
 142    OK, but for multi-threaded debugging we only insert the current
 143    ABI's breakpoint instruction.  For now at least.  */
 144 static const unsigned long arm_eabi_breakpoint = 0xe7f001f0;
 145
 146 static int
 147 arm_breakpoint_at (CORE_ADDR where)
 148 {
 149   unsigned long insn;
 150
 151   (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
 152   if (insn == arm_breakpoint)
 153     return 1;
 154
 155   if (insn == arm_eabi_breakpoint)
 156     return 1;
 157
 158   /* If necessary, recognize more trap instructions here.  GDB only uses the
 159      two.  */
 160
 161   return 0;
 162 }
 163
 164 /* We only place breakpoints in empty marker functions, and thread locking
 165    is outside of the function.  So rather than importing software single-step,
 166    we can just run until exit.  */
 167 static CORE_ADDR
 168 arm_reinsert_addr ()
 169 {
 170   unsigned long pc;
 171   collect_register_by_name ("lr", &pc);
 172   return pc;
 173 }
 174
 175 /* Fetch the thread-local storage pointer for libthread_db.  */
 176
 177 ps_err_e
 178 ps_get_thread_area (const struct ps_prochandle *ph,
 179                     lwpid_t lwpid, int idx, void **base)
 180 {
 181   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 182     return PS_ERR;
 183
 184   /* IDX is the bias from the thread pointer to the beginning of the
 185      thread descriptor.  It has to be subtracted due to implementation
 186      quirks in libthread_db.  */
 187   *base = (void *) ((char *)*base - idx);
 188
 189   return PS_OK;
 190 }
 191
 192 struct regset_info target_regsets[] = {
 193   { PTRACE_GETREGS, PTRACE_SETREGS, 18 * 4,
 194     GENERAL_REGS,
 195     arm_fill_gregset, arm_store_gregset },
 196 #ifdef __IWMMXT__
 197   { PTRACE_GETWMMXREGS, PTRACE_SETWMMXREGS, 16 * 8 + 6 * 4,
 198     EXTENDED_REGS,
 199     arm_fill_wmmxregset, arm_store_wmmxregset },
 200 #endif
 201   { 0, 0, -1, -1, NULL, NULL }
 202 };
 203
 204 struct linux_target_ops the_low_target = {
 205   arm_num_regs,
 206   arm_regmap,
 207   arm_cannot_fetch_register,
 208   arm_cannot_store_register,
 209   arm_get_pc,
 210   arm_set_pc,
 211 #ifndef __ARM_EABI__
 212   (const unsigned char *) &arm_breakpoint,
 213 #else
 214   (const unsigned char *) &arm_eabi_breakpoint,
 215 #endif
 216   arm_breakpoint_len,
 217   arm_reinsert_addr,
 218   0,
 219   arm_breakpoint_at,
 220 };