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 73
  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 static int mips_regmap[] = {
  54   -1,  1,  2,  3,  4,  5,  6,  7,
  55   8,  9,  10, 11, 12, 13, 14, 15,
  56   16, 17, 18, 19, 20, 21, 22, 23,
  57   24, 25, 26, 27, 28, 29, 30, 31,
  58
  59   -1, MMLO, MMHI, BADVADDR, CAUSE, PC,
  60
  61   FPR_BASE,      FPR_BASE + 1,  FPR_BASE + 2,  FPR_BASE + 3,
  62   FPR_BASE + 4,  FPR_BASE + 5,  FPR_BASE + 6,  FPR_BASE + 7,
  63   FPR_BASE + 8,  FPR_BASE + 8,  FPR_BASE + 10, FPR_BASE + 11,
  64   FPR_BASE + 12, FPR_BASE + 13, FPR_BASE + 14, FPR_BASE + 15,
  65   FPR_BASE + 16, FPR_BASE + 17, FPR_BASE + 18, FPR_BASE + 19,
  66   FPR_BASE + 20, FPR_BASE + 21, FPR_BASE + 22, FPR_BASE + 23,
  67   FPR_BASE + 24, FPR_BASE + 25, FPR_BASE + 26, FPR_BASE + 27,
  68   FPR_BASE + 28, FPR_BASE + 29, FPR_BASE + 30, FPR_BASE + 31,
  69   FPC_CSR, FPC_EIR,
  70
  71   0
  72 };
  73
  74 /* From mips-linux-nat.c.  */
  75
  76 /* Pseudo registers can not be read.  ptrace does not provide a way to
  77    read (or set) PS_REGNUM, and there's no point in reading or setting
  78    ZERO_REGNUM.  We also can not set BADVADDR, CAUSE, or FCRIR via
  79    ptrace().  */
  80
  81 static int
  82 mips_cannot_fetch_register (int regno)
  83 {
  84   if (mips_regmap[regno] == -1)
  85     return 1;
  86
  87   if (find_regno ("r0") == regno)
  88     return 1;
  89
  90   return 0;
  91 }
  92
  93 static int
  94 mips_cannot_store_register (int regno)
  95 {
  96   if (mips_regmap[regno] == -1)
  97     return 1;
  98
  99   if (find_regno ("r0") == regno)
 100     return 1;
 101
 102   if (find_regno ("cause") == regno)
 103     return 1;
 104
 105   if (find_regno ("badvaddr") == regno)
 106     return 1;
 107
 108   if (find_regno ("fir") == regno)
 109     return 1;
 110
 111   return 0;
 112 }
 113
 114 static CORE_ADDR
 115 mips_get_pc ()
 116 {
 117   union mips_register pc;
 118   collect_register_by_name ("pc", pc.buf);
 119   return register_size (0) == 4 ? pc.reg32 : pc.reg64;
 120 }
 121
 122 static void
 123 mips_set_pc (CORE_ADDR pc)
 124 {
 125   union mips_register newpc;
 126   if (register_size (0) == 4)
 127     newpc.reg32 = pc;
 128   else
 129     newpc.reg64 = pc;
 130
 131   supply_register_by_name ("pc", newpc.buf);
 132 }
 133
 134 /* Correct in either endianness.  */
 135 static const unsigned int mips_breakpoint = 0x0005000d;
 136 #define mips_breakpoint_len 4
 137
 138 /* We only place breakpoints in empty marker functions, and thread locking
 139    is outside of the function.  So rather than importing software single-step,
 140    we can just run until exit.  */
 141 static CORE_ADDR
 142 mips_reinsert_addr ()
 143 {
 144   union mips_register ra;
 145   collect_register_by_name ("r31", ra.buf);
 146   return register_size (0) == 4 ? ra.reg32 : ra.reg64;
 147 }
 148
 149 static int
 150 mips_breakpoint_at (CORE_ADDR where)
 151 {
 152   unsigned int insn;
 153
 154   (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
 155   if (insn == mips_breakpoint)
 156     return 1;
 157
 158   /* If necessary, recognize more trap instructions here.  GDB only uses the
 159      one.  */
 160   return 0;
 161 }
 162
 163 /* Fetch the thread-local storage pointer for libthread_db.  */
 164
 165 ps_err_e
 166 ps_get_thread_area (const struct ps_prochandle *ph,
 167                     lwpid_t lwpid, int idx, void **base)
 168 {
 169   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 170     return PS_ERR;
 171
 172   /* IDX is the bias from the thread pointer to the beginning of the
 173      thread descriptor.  It has to be subtracted due to implementation
 174      quirks in libthread_db.  */
 175   *base = (void *) ((char *)*base - idx);
 176
 177   return PS_OK;
 178 }
 179
 180 #ifdef HAVE_PTRACE_GETREGS
 181
 182 static void
 183 mips_collect_register (int use_64bit, int regno, union mips_register *reg)
 184 {
 185   union mips_register tmp_reg;
 186
 187   if (use_64bit)
 188     {
 189       collect_register (regno, &tmp_reg.reg64);
 190       *reg = tmp_reg;
 191     }
 192   else
 193     {
 194       collect_register (regno, &tmp_reg.reg32);
 195       reg->reg64 = tmp_reg.reg32;
 196     }
 197 }
 198
 199 static void
 200 mips_supply_register (int use_64bit, int regno, const union mips_register *reg)
 201 {
 202   int offset = 0;
 203
 204   /* For big-endian 32-bit targets, ignore the high four bytes of each
 205      eight-byte slot.  */
 206   if (__BYTE_ORDER == __BIG_ENDIAN && !use_64bit)
 207     offset = 4;
 208
 209   supply_register (regno, reg->buf + offset);
 210 }
 211
 212 static void
 213 mips_collect_register_32bit (int use_64bit, int regno, unsigned char *buf)
 214 {
 215   union mips_register tmp_reg;
 216   int reg32;
 217
 218   mips_collect_register (use_64bit, regno, &tmp_reg);
 219   reg32 = tmp_reg.reg64;
 220   memcpy (buf, &reg32, 4);
 221 }
 222
 223 static void
 224 mips_supply_register_32bit (int use_64bit, int regno, const unsigned char *buf)
 225 {
 226   union mips_register tmp_reg;
 227   int reg32;
 228
 229   memcpy (&reg32, buf, 4);
 230   tmp_reg.reg64 = reg32;
 231   mips_supply_register (use_64bit, regno, &tmp_reg);
 232 }
 233
 234 static void
 235 mips_fill_gregset (void *buf)
 236 {
 237   union mips_register *regset = buf;
 238   int i, use_64bit;
 239
 240   use_64bit = (register_size (0) == 8);
 241
 242   for (i = 1; i < 32; i++)
 243     mips_collect_register (use_64bit, i, regset + i);
 244
 245   mips_collect_register (use_64bit, find_regno ("lo"), regset + 32);
 246   mips_collect_register (use_64bit, find_regno ("hi"), regset + 33);
 247   mips_collect_register (use_64bit, find_regno ("pc"), regset + 34);
 248   mips_collect_register (use_64bit, find_regno ("badvaddr"), regset + 35);
 249   mips_collect_register (use_64bit, find_regno ("status"), regset + 36);
 250   mips_collect_register (use_64bit, find_regno ("cause"), regset + 37);
 251
 252   mips_collect_register (use_64bit, find_regno ("restart"), regset + 0);
 253 }
 254
 255 static void
 256 mips_store_gregset (const void *buf)
 257 {
 258   const union mips_register *regset = buf;
 259   int i, use_64bit;
 260
 261   use_64bit = (register_size (0) == 8);
 262
 263   for (i = 0; i < 32; i++)
 264     mips_supply_register (use_64bit, i, regset + i);
 265
 266   mips_supply_register (use_64bit, find_regno ("lo"), regset + 32);
 267   mips_supply_register (use_64bit, find_regno ("hi"), regset + 33);
 268   mips_supply_register (use_64bit, find_regno ("pc"), regset + 34);
 269   mips_supply_register (use_64bit, find_regno ("badvaddr"), regset + 35);
 270   mips_supply_register (use_64bit, find_regno ("status"), regset + 36);
 271   mips_supply_register (use_64bit, find_regno ("cause"), regset + 37);
 272
 273   mips_supply_register (use_64bit, find_regno ("restart"), regset + 0);
 274 }
 275
 276 static void
 277 mips_fill_fpregset (void *buf)
 278 {
 279   union mips_register *regset = buf;
 280   int i, use_64bit, first_fp, big_endian;
 281
 282   use_64bit = (register_size (0) == 8);
 283   first_fp = find_regno ("f0");
 284   big_endian = (__BYTE_ORDER == __BIG_ENDIAN);
 285
 286   /* See GDB for a discussion of this peculiar layout.  */
 287   for (i = 0; i < 32; i++)
 288     if (use_64bit)
 289       collect_register (first_fp + i, regset[i].buf);
 290     else
 291       collect_register (first_fp + i,
 292                         regset[i & ~1].buf + 4 * (big_endian != (i & 1)));
 293
 294   mips_collect_register_32bit (use_64bit, find_regno ("fcsr"), regset[32].buf);
 295   mips_collect_register_32bit (use_64bit, find_regno ("fir"),
 296                                regset[32].buf + 4);
 297 }
 298
 299 static void
 300 mips_store_fpregset (const void *buf)
 301 {
 302   const union mips_register *regset = buf;
 303   int i, use_64bit, first_fp, big_endian;
 304
 305   use_64bit = (register_size (0) == 8);
 306   first_fp = find_regno ("f0");
 307   big_endian = (__BYTE_ORDER == __BIG_ENDIAN);
 308
 309   /* See GDB for a discussion of this peculiar layout.  */
 310   for (i = 0; i < 32; i++)
 311     if (use_64bit)
 312       supply_register (first_fp + i, regset[i].buf);
 313     else
 314       supply_register (first_fp + i,
 315                        regset[i & ~1].buf + 4 * (big_endian != (i & 1)));
 316
 317   mips_supply_register_32bit (use_64bit, find_regno ("fcsr"), regset[32].buf);
 318   mips_supply_register_32bit (use_64bit, find_regno ("fir"),
 319                               regset[32].buf + 4);
 320 }
 321 #endif /* HAVE_PTRACE_GETREGS */
 322
 323 struct regset_info target_regsets[] = {
 324 #ifdef HAVE_PTRACE_GETREGS
 325   { PTRACE_GETREGS, PTRACE_SETREGS, 38 * 8, GENERAL_REGS,
 326     mips_fill_gregset, mips_store_gregset },
 327   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 33 * 8, FP_REGS,
 328     mips_fill_fpregset, mips_store_fpregset },
 329 #endif /* HAVE_PTRACE_GETREGS */
 330   { 0, 0, -1, -1, NULL, NULL }
 331 };
 332
 333 struct linux_target_ops the_low_target = {
 334   mips_num_regs,
 335   mips_regmap,
 336   mips_cannot_fetch_register,
 337   mips_cannot_store_register,
 338   mips_get_pc,
 339   mips_set_pc,
 340   (const unsigned char *) &mips_breakpoint,
 341   mips_breakpoint_len,
 342   mips_reinsert_addr,
 343   0,
 344   mips_breakpoint_at,
 345 };