gdb/mips-linux-nat.c

   1 /* Native-dependent code for GNU/Linux on MIPS processors.
   2
   3    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include "defs.h"
  24 #include "inferior.h"
  25 #include "mips-tdep.h"
  26 #include "target.h"
  27 #include "linux-nat.h"
  28 #include "mips-linux-tdep.h"
  29
  30 #include "gdb_proc_service.h"
  31
  32 #include <sys/ptrace.h>
  33
  34 #ifndef PTRACE_GET_THREAD_AREA
  35 #define PTRACE_GET_THREAD_AREA 25
  36 #endif
  37
  38 /* Assume that we have PTRACE_GETREGS et al. support.  If we do not,
  39    we'll clear this and use PTRACE_PEEKUSER instead.  */
  40 static int have_ptrace_regsets = 1;
  41
  42 /* Saved function pointers to fetch and store a single register using
  43    PTRACE_PEEKUSER and PTRACE_POKEUSER.  */
  44
  45 void (*super_fetch_registers) (int);
  46 void (*super_store_registers) (int);
  47
  48 /* Pseudo registers can not be read.  ptrace does not provide a way to
  49    read (or set) MIPS_PS_REGNUM, and there's no point in reading or
  50    setting MIPS_ZERO_REGNUM.  We also can not set BADVADDR, CAUSE, or
  51    FCRIR via ptrace().  */
  52
  53 int
  54 mips_linux_cannot_fetch_register (int regno)
  55 {
  56   if (regno > MIPS_ZERO_REGNUM && regno < MIPS_ZERO_REGNUM + 32)
  57     return 0;
  58   else if (regno >= mips_regnum (current_gdbarch)->fp0
  59            && regno <= mips_regnum (current_gdbarch)->fp0 + 32)
  60     return 0;
  61   else if (regno == mips_regnum (current_gdbarch)->lo
  62            || regno == mips_regnum (current_gdbarch)->hi
  63            || regno == mips_regnum (current_gdbarch)->badvaddr
  64            || regno == mips_regnum (current_gdbarch)->cause
  65            || regno == mips_regnum (current_gdbarch)->pc
  66            || regno == mips_regnum (current_gdbarch)->fp_control_status
  67            || regno == mips_regnum (current_gdbarch)->fp_implementation_revision)
  68     return 0;
  69   else
  70     return 1;
  71 }
  72
  73 int
  74 mips_linux_cannot_store_register (int regno)
  75 {
  76   if (regno > MIPS_ZERO_REGNUM && regno < MIPS_ZERO_REGNUM + 32)
  77     return 0;
  78   else if (regno >= FP0_REGNUM && regno <= FP0_REGNUM + 32)
  79     return 0;
  80   else if (regno == mips_regnum (current_gdbarch)->lo
  81            || regno == mips_regnum (current_gdbarch)->hi
  82            || regno == mips_regnum (current_gdbarch)->pc
  83            || regno == mips_regnum (current_gdbarch)->fp_control_status)
  84     return 0;
  85   else
  86     return 1;
  87 }
  88
  89 /* Fetch the thread-local storage pointer for libthread_db.  */
  90
  91 ps_err_e
  92 ps_get_thread_area (const struct ps_prochandle *ph,
  93                     lwpid_t lwpid, int idx, void **base)
  94 {
  95   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
  96     return PS_ERR;
  97
  98   /* IDX is the bias from the thread pointer to the beginning of the
  99      thread descriptor.  It has to be subtracted due to implementation
 100      quirks in libthread_db.  */
 101   *base = (void *) ((char *)*base - idx);
 102
 103   return PS_OK;
 104 }
 105
 106 /* Fetch REGNO (or all registers if REGNO == -1) from the target
 107    using PTRACE_GETREGS et al.  */
 108
 109 static void
 110 mips64_linux_regsets_fetch_registers (int regno)
 111 {
 112   int is_fp;
 113   int tid;
 114
 115   if (regno >= mips_regnum (current_gdbarch)->fp0
 116       && regno <= mips_regnum (current_gdbarch)->fp0 + 32)
 117     is_fp = 1;
 118   else if (regno == mips_regnum (current_gdbarch)->fp_control_status)
 119     is_fp = 1;
 120   else if (regno == mips_regnum (current_gdbarch)->fp_implementation_revision)
 121     is_fp = 1;
 122   else
 123     is_fp = 0;
 124
 125   tid = ptid_get_lwp (inferior_ptid);
 126   if (tid == 0)
 127     tid = ptid_get_pid (inferior_ptid);
 128
 129   if (regno == -1 || !is_fp)
 130     {
 131       mips64_elf_gregset_t regs;
 132
 133       if (ptrace (PTRACE_GETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
 134         {
 135           if (errno == EIO)
 136             {
 137               have_ptrace_regsets = 0;
 138               return;
 139             }
 140           perror_with_name (_("Couldn't get registers"));
 141         }
 142
 143       mips64_supply_gregset (&regs);
 144     }
 145
 146   if (regno == -1 || is_fp)
 147     {
 148       mips64_elf_fpregset_t fp_regs;
 149
 150       if (ptrace (PTRACE_GETFPREGS, tid, 0L,
 151                   (PTRACE_TYPE_ARG3) &fp_regs) == -1)
 152         {
 153           if (errno == EIO)
 154             {
 155               have_ptrace_regsets = 0;
 156               return;
 157             }
 158           perror_with_name (_("Couldn't get FP registers"));
 159         }
 160
 161       mips64_supply_fpregset (&fp_regs);
 162     }
 163 }
 164
 165 /* Store REGNO (or all registers if REGNO == -1) to the target
 166    using PTRACE_SETREGS et al.  */
 167
 168 static void
 169 mips64_linux_regsets_store_registers (int regno)
 170 {
 171   int is_fp;
 172   int tid;
 173
 174   if (regno >= mips_regnum (current_gdbarch)->fp0
 175       && regno <= mips_regnum (current_gdbarch)->fp0 + 32)
 176     is_fp = 1;
 177   else if (regno == mips_regnum (current_gdbarch)->fp_control_status)
 178     is_fp = 1;
 179   else if (regno == mips_regnum (current_gdbarch)->fp_implementation_revision)
 180     is_fp = 1;
 181   else
 182     is_fp = 0;
 183
 184   tid = ptid_get_lwp (inferior_ptid);
 185   if (tid == 0)
 186     tid = ptid_get_pid (inferior_ptid);
 187
 188   if (regno == -1 || !is_fp)
 189     {
 190       mips64_elf_gregset_t regs;
 191
 192       if (ptrace (PTRACE_GETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
 193         perror_with_name (_("Couldn't get registers"));
 194
 195       mips64_fill_gregset (&regs, regno);
 196
 197       if (ptrace (PTRACE_SETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
 198         perror_with_name (_("Couldn't set registers"));
 199     }
 200
 201   if (regno == -1 || is_fp)
 202     {
 203       mips64_elf_fpregset_t fp_regs;
 204
 205       if (ptrace (PTRACE_GETFPREGS, tid, 0L,
 206                   (PTRACE_TYPE_ARG3) &fp_regs) == -1)
 207         perror_with_name (_("Couldn't get FP registers"));
 208
 209       mips64_fill_fpregset (&fp_regs, regno);
 210
 211       if (ptrace (PTRACE_SETFPREGS, tid, 0L,
 212                   (PTRACE_TYPE_ARG3) &fp_regs) == -1)
 213         perror_with_name (_("Couldn't set FP registers"));
 214     }
 215 }
 216
 217 /* Fetch REGNO (or all registers if REGNO == -1) from the target
 218    using any working method.  */
 219
 220 static void
 221 mips64_linux_fetch_registers (int regnum)
 222 {
 223   /* Unless we already know that PTRACE_GETREGS does not work, try it.  */
 224   if (have_ptrace_regsets)
 225     mips64_linux_regsets_fetch_registers (regnum);
 226
 227   /* If we know, or just found out, that PTRACE_GETREGS does not work, fall
 228      back to PTRACE_PEEKUSER.  */
 229   if (!have_ptrace_regsets)
 230     super_fetch_registers (regnum);
 231 }
 232
 233 /* Store REGNO (or all registers if REGNO == -1) to the target
 234    using any working method.  */
 235
 236 static void
 237 mips64_linux_store_registers (int regnum)
 238 {
 239   /* Unless we already know that PTRACE_GETREGS does not work, try it.  */
 240   if (have_ptrace_regsets)
 241     mips64_linux_regsets_store_registers (regnum);
 242
 243   /* If we know, or just found out, that PTRACE_GETREGS does not work, fall
 244      back to PTRACE_PEEKUSER.  */
 245   if (!have_ptrace_regsets)
 246     super_store_registers (regnum);
 247 }
 248
 249 void _initialize_mips_linux_nat (void);
 250
 251 void
 252 _initialize_mips_linux_nat (void)
 253 {
 254   struct target_ops *t = linux_target ();
 255
 256   super_fetch_registers = t->to_fetch_registers;
 257   super_store_registers = t->to_store_registers;
 258
 259   t->to_fetch_registers = mips64_linux_fetch_registers;
 260   t->to_store_registers = mips64_linux_store_registers;
 261
 262   linux_nat_add_target (t);
 263 }