gdb/gdbserver/linux-mips-low.c

   1 /* GNU/Linux/MIPS specific low level interface, for the remote server for GDB.
   2    Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2005, 2006, 2007
   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., 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 #include <endian.h>
  27
  28 #include "gdb_proc_service.h"
  29
  30 #ifndef PTRACE_GET_THREAD_AREA
  31 #define PTRACE_GET_THREAD_AREA 25
  32 #endif
  33
  34 #ifdef HAVE_SYS_REG_H
  35 #include <sys/reg.h>
  36 #endif
  37
  38 #define mips_num_regs 90
  39
  40 #include <asm/ptrace.h>
  41
  42 union mips_register
  43 {
  44   unsigned char buf[8];
  45
  46   /* Deliberately signed, for proper sign extension.  */
  47   int reg32;
  48   long long reg64;
  49 };
  50
  51 /* Return the ptrace ``address'' of register REGNO. */
  52
  53 /* Matches mips_generic32_regs */
  54 static int mips_regmap[] = {
  55   0,  1,  2,  3,  4,  5,  6,  7,
  56   8,  9,  10, 11, 12, 13, 14, 15,
  57   16, 17, 18, 19, 20, 21, 22, 23,
  58   24, 25, 26, 27, 28, 29, 30, 31,
  59
  60   -1, MMLO, MMHI, BADVADDR, CAUSE, PC,
  61
  62   FPR_BASE,      FPR_BASE + 1,  FPR_BASE + 2,  FPR_BASE + 3,
  63   FPR_BASE + 4,  FPR_BASE + 5,  FPR_BASE + 6,  FPR_BASE + 7,
  64   FPR_BASE + 8,  FPR_BASE + 8,  FPR_BASE + 10, FPR_BASE + 11,
  65   FPR_BASE + 12, FPR_BASE + 13, FPR_BASE + 14, FPR_BASE + 15,
  66   FPR_BASE + 16, FPR_BASE + 17, FPR_BASE + 18, FPR_BASE + 19,
  67   FPR_BASE + 20, FPR_BASE + 21, FPR_BASE + 22, FPR_BASE + 23,
  68   FPR_BASE + 24, FPR_BASE + 25, FPR_BASE + 26, FPR_BASE + 27,
  69   FPR_BASE + 28, FPR_BASE + 29, FPR_BASE + 30, FPR_BASE + 31,
  70   FPC_CSR, FPC_EIR,
  71
  72   -1, -1,
  73   -1, -1, -1, -1, -1, -1, -1, -1,
  74   -1, -1, -1, -1, -1, -1, -1, -1,
  75 };
  76
  77 /* From mips-linux-nat.c.  */
  78
  79 /* Pseudo registers can not be read.  ptrace does not provide a way to
  80    read (or set) PS_REGNUM, and there's no point in reading or setting
  81    ZERO_REGNUM.  We also can not set BADVADDR, CAUSE, or FCRIR via
  82    ptrace().  */
  83
  84 static int
  85 mips_cannot_fetch_register (int regno)
  86 {
  87   if (mips_regmap[regno] == -1)
  88     return 1;
  89
  90   if (find_regno ("zero") == regno)
  91     return 1;
  92
  93   return 0;
  94 }
  95
  96 static int
  97 mips_cannot_store_register (int regno)
  98 {
  99   if (mips_regmap[regno] == -1)
 100     return 1;
 101
 102   if (find_regno ("zero") == regno)
 103     return 1;
 104
 105   if (find_regno ("cause") == regno)
 106     return 1;
 107
 108   if (find_regno ("bad") == regno)
 109     return 1;
 110
 111   if (find_regno ("fir") == regno)
 112     return 1;
 113
 114   return 0;
 115 }
 116
 117 static CORE_ADDR
 118 mips_get_pc ()
 119 {
 120   union mips_register pc;
 121   collect_register_by_name ("pc", pc.buf);
 122   return register_size (0) == 4 ? pc.reg32 : pc.reg64;
 123 }
 124
 125 static void
 126 mips_set_pc (CORE_ADDR pc)
 127 {
 128   union mips_register newpc;
 129   if (register_size (0) == 4)
 130     newpc.reg32 = pc;
 131   else
 132     newpc.reg64 = pc;
 133
 134   supply_register_by_name ("pc", newpc.buf);
 135 }
 136
 137 /* Correct in either endianness.  */
 138 static const unsigned int mips_breakpoint = 0x0005000d;
 139 #define mips_breakpoint_len 4
 140
 141 /* We only place breakpoints in empty marker functions, and thread locking
 142    is outside of the function.  So rather than importing software single-step,
 143    we can just run until exit.  */
 144 static CORE_ADDR
 145 mips_reinsert_addr ()
 146 {
 147   union mips_register ra;
 148   collect_register_by_name ("ra", ra.buf);
 149   return register_size (0) == 4 ? ra.reg32 : ra.reg64;
 150 }
 151
 152 static int
 153 mips_breakpoint_at (CORE_ADDR where)
 154 {
 155   unsigned int insn;
 156
 157   (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
 158   if (insn == mips_breakpoint)
 159     return 1;
 160
 161   /* If necessary, recognize more trap instructions here.  GDB only uses the
 162      one.  */
 163   return 0;
 164 }
 165
 166 /* Fetch the thread-local storage pointer for libthread_db.  */
 167
 168 ps_err_e
 169 ps_get_thread_area (const struct ps_prochandle *ph,
 170                     lwpid_t lwpid, int idx, void **base)
 171 {
 172   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 173     return PS_ERR;
 174
 175   /* IDX is the bias from the thread pointer to the beginning of the
 176      thread descriptor.  It has to be subtracted due to implementation
 177      quirks in libthread_db.  */
 178   *base = (void *) ((char *)*base - idx);
 179
 180   return PS_OK;
 181 }
 182
 183 #ifdef HAVE_PTRACE_GETREGS
 184
 185 static void
 186 mips_collect_register (int use_64bit, int regno, union mips_register *reg)
 187 {
 188   union mips_register tmp_reg;
 189
 190   if (use_64bit)
 191     {
 192       collect_register (regno, &tmp_reg.reg64);
 193       *reg = tmp_reg;
 194     }
 195   else
 196     {
 197       collect_register (regno, &tmp_reg.reg32);
 198       reg->reg64 = tmp_reg.reg32;
 199     }
 200 }
 201
 202 static void
 203 mips_supply_register (int use_64bit, int regno, const union mips_register *reg)
 204 {
 205   int offset = 0;
 206
 207   /* For big-endian 32-bit targets, ignore the high four bytes of each
 208      eight-byte slot.  */
 209   if (__BYTE_ORDER == __BIG_ENDIAN && !use_64bit)
 210     offset = 4;
 211
 212   supply_register (regno, reg->buf + offset);
 213 }
 214
 215 static void
 216 mips_collect_register_32bit (int use_64bit, int regno, unsigned char *buf)
 217 {
 218   union mips_register tmp_reg;
 219   int reg32;
 220
 221   mips_collect_register (use_64bit, regno, &tmp_reg);
 222   reg32 = tmp_reg.reg64;
 223   memcpy (buf, &reg32, 4);
 224 }
 225
 226 static void
 227 mips_supply_register_32bit (int use_64bit, int regno, const unsigned char *buf)
 228 {
 229   union mips_register tmp_reg;
 230   int reg32;
 231
 232   memcpy (&reg32, buf, 4);
 233   tmp_reg.reg64 = reg32;
 234   mips_supply_register (use_64bit, regno, &tmp_reg);
 235 }
 236
 237 static void
 238 mips_fill_gregset (void *buf)
 239 {
 240   union mips_register *regset = buf;
 241   int i, use_64bit;
 242
 243   use_64bit = (register_size (0) == 8);
 244
 245   for (i = 0; i < 32; i++)
 246     mips_collect_register (use_64bit, i, regset + i);
 247
 248   mips_collect_register (use_64bit, find_regno ("lo"), regset + 32);
 249   mips_collect_register (use_64bit, find_regno ("hi"), regset + 33);
 250   mips_collect_register (use_64bit, find_regno ("pc"), regset + 34);
 251   mips_collect_register (use_64bit, find_regno ("bad"), regset + 35);
 252   mips_collect_register (use_64bit, find_regno ("sr"), regset + 36);
 253   mips_collect_register (use_64bit, find_regno ("cause"), regset + 37);
 254 }
 255
 256 static void
 257 mips_store_gregset (const void *buf)
 258 {
 259   const union mips_register *regset = buf;
 260   int i, use_64bit;
 261
 262   use_64bit = (register_size (0) == 8);
 263
 264   for (i = 0; i < 32; i++)
 265     mips_supply_register (use_64bit, i, regset + i);
 266
 267   mips_supply_register (use_64bit, find_regno ("lo"), regset + 32);
 268   mips_supply_register (use_64bit, find_regno ("hi"), regset + 33);
 269   mips_supply_register (use_64bit, find_regno ("pc"), regset + 34);
 270   mips_supply_register (use_64bit, find_regno ("bad"), regset + 35);
 271   mips_supply_register (use_64bit, find_regno ("sr"), regset + 36);
 272   mips_supply_register (use_64bit, find_regno ("cause"), regset + 37);
 273 }
 274
 275 static void
 276 mips_fill_fpregset (void *buf)
 277 {
 278   union mips_register *regset = buf;
 279   int i, use_64bit, first_fp, big_endian;
 280
 281   use_64bit = (register_size (0) == 8);
 282   first_fp = find_regno ("f0");
 283   big_endian = (__BYTE_ORDER == __BIG_ENDIAN);
 284
 285   /* See GDB for a discussion of this peculiar layout.  */
 286   for (i = 0; i < 32; i++)
 287     if (use_64bit)
 288       collect_register (first_fp + i, regset[i].buf);
 289     else
 290       collect_register (first_fp + i,
 291                         regset[i & ~1].buf + 4 * (big_endian != (i & 1)));
 292
 293   mips_collect_register_32bit (use_64bit, find_regno ("fsr"), regset[32].buf);
 294   mips_collect_register_32bit (use_64bit, find_regno ("fir"),
 295                                regset[32].buf + 4);
 296 }
 297
 298 static void
 299 mips_store_fpregset (const void *buf)
 300 {
 301   const union mips_register *regset = buf;
 302   int i, use_64bit, first_fp, big_endian;
 303
 304   use_64bit = (register_size (0) == 8);
 305   first_fp = find_regno ("f0");
 306   big_endian = (__BYTE_ORDER == __BIG_ENDIAN);
 307
 308   /* See GDB for a discussion of this peculiar layout.  */
 309   for (i = 0; i < 32; i++)
 310     if (use_64bit)
 311       supply_register (first_fp + i, regset[i].buf);
 312     else
 313       supply_register (first_fp + i,
 314                        regset[i & ~1].buf + 4 * (big_endian != (i & 1)));
 315
 316   mips_supply_register_32bit (use_64bit, find_regno ("fsr"), regset[32].buf);
 317   mips_supply_register_32bit (use_64bit, find_regno ("fir"),
 318                               regset[32].buf + 4);
 319 }
 320 #endif /* HAVE_PTRACE_GETREGS */
 321
 322 struct regset_info target_regsets[] = {
 323 #ifdef HAVE_PTRACE_GETREGS
 324   { PTRACE_GETREGS, PTRACE_SETREGS, 38 * 8, GENERAL_REGS,
 325     mips_fill_gregset, mips_store_gregset },
 326   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 33 * 8, FP_REGS,
 327     mips_fill_fpregset, mips_store_fpregset },
 328 #endif /* HAVE_PTRACE_GETREGS */
 329   { 0, 0, -1, -1, NULL, NULL }
 330 };
 331
 332 struct linux_target_ops the_low_target = {
 333   mips_num_regs,
 334   mips_regmap,
 335   mips_cannot_fetch_register,
 336   mips_cannot_store_register,
 337   mips_get_pc,
 338   mips_set_pc,
 339   (const unsigned char *) &mips_breakpoint,
 340   mips_breakpoint_len,
 341   mips_reinsert_addr,
 342   0,
 343   mips_breakpoint_at,
 344 };