gdb/gdbserver/linux-i386-low.c

   1 /* GNU/Linux/i386 specific low level interface, for the remote server for GDB.
   2    Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006,
   3    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 #include "i387-fp.h"
  25
  26 #include "gdb_proc_service.h"
  27
  28 #include <sys/ptrace.h>
  29
  30 #ifdef HAVE_SYS_REG_H
  31 #include <sys/reg.h>
  32 #endif
  33
  34 #ifndef PTRACE_GET_THREAD_AREA
  35 #define PTRACE_GET_THREAD_AREA 25
  36 #endif
  37
  38 /* This module only supports access to the general purpose registers.  */
  39
  40 #define i386_num_regs 16
  41
  42 /* This stuff comes from i386-linux-nat.c.  */
  43
  44 /* Mapping between the general-purpose registers in `struct user'
  45    format and GDB's register array layout.  */
  46 static int i386_regmap[] =
  47 {
  48   EAX * 4, ECX * 4, EDX * 4, EBX * 4,
  49   UESP * 4, EBP * 4, ESI * 4, EDI * 4,
  50   EIP * 4, EFL * 4, CS * 4, SS * 4,
  51   DS * 4, ES * 4, FS * 4, GS * 4
  52 };
  53
  54 /* Called by libthread_db.  */
  55
  56 ps_err_e
  57 ps_get_thread_area (const struct ps_prochandle *ph,
  58                     lwpid_t lwpid, int idx, void **base)
  59 {
  60   unsigned int desc[4];
  61
  62   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid,
  63               (void *) idx, (unsigned long) &desc) < 0)
  64     return PS_ERR;
  65
  66   *(int *)base = desc[1];
  67   return PS_OK;
  68 }
  69
  70 static int
  71 i386_cannot_store_register (int regno)
  72 {
  73   return (regno >= i386_num_regs);
  74 }
  75
  76 static int
  77 i386_cannot_fetch_register (int regno)
  78 {
  79   return (regno >= i386_num_regs);
  80 }
  81
  82
  83 #ifdef HAVE_PTRACE_GETREGS
  84 #include <sys/procfs.h>
  85 #include <sys/ptrace.h>
  86
  87 static void
  88 i386_fill_gregset (void *buf)
  89 {
  90   int i;
  91
  92   for (i = 0; i < i386_num_regs; i++)
  93     collect_register (i, ((char *) buf) + i386_regmap[i]);
  94
  95   collect_register_by_name ("orig_eax", ((char *) buf) + ORIG_EAX * 4);
  96 }
  97
  98 static void
  99 i386_store_gregset (const void *buf)
 100 {
 101   int i;
 102
 103   for (i = 0; i < i386_num_regs; i++)
 104     supply_register (i, ((char *) buf) + i386_regmap[i]);
 105
 106   supply_register_by_name ("orig_eax", ((char *) buf) + ORIG_EAX * 4);
 107 }
 108
 109 static void
 110 i386_fill_fpregset (void *buf)
 111 {
 112   i387_cache_to_fsave (buf);
 113 }
 114
 115 static void
 116 i386_store_fpregset (const void *buf)
 117 {
 118   i387_fsave_to_cache (buf);
 119 }
 120
 121 static void
 122 i386_fill_fpxregset (void *buf)
 123 {
 124   i387_cache_to_fxsave (buf);
 125 }
 126
 127 static void
 128 i386_store_fpxregset (const void *buf)
 129 {
 130   i387_fxsave_to_cache (buf);
 131 }
 132
 133 #endif /* HAVE_PTRACE_GETREGS */
 134
 135 struct regset_info target_regsets[] = {
 136 #ifdef HAVE_PTRACE_GETREGS
 137   { PTRACE_GETREGS, PTRACE_SETREGS, sizeof (elf_gregset_t),
 138     GENERAL_REGS,
 139     i386_fill_gregset, i386_store_gregset },
 140 # ifdef HAVE_PTRACE_GETFPXREGS
 141   { PTRACE_GETFPXREGS, PTRACE_SETFPXREGS, sizeof (elf_fpxregset_t),
 142     EXTENDED_REGS,
 143     i386_fill_fpxregset, i386_store_fpxregset },
 144 # endif
 145   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, sizeof (elf_fpregset_t),
 146     FP_REGS,
 147     i386_fill_fpregset, i386_store_fpregset },
 148 #endif /* HAVE_PTRACE_GETREGS */
 149   { 0, 0, -1, -1, NULL, NULL }
 150 };
 151
 152 static const unsigned char i386_breakpoint[] = { 0xCC };
 153 #define i386_breakpoint_len 1
 154
 155 extern int debug_threads;
 156
 157 static CORE_ADDR
 158 i386_get_pc ()
 159 {
 160   unsigned long pc;
 161
 162   collect_register_by_name ("eip", &pc);
 163
 164   if (debug_threads)
 165     fprintf (stderr, "stop pc (before any decrement) is %08lx\n", pc);
 166   return pc;
 167 }
 168
 169 static void
 170 i386_set_pc (CORE_ADDR newpc)
 171 {
 172   if (debug_threads)
 173     fprintf (stderr, "set pc to %08lx\n", (long) newpc);
 174   supply_register_by_name ("eip", &newpc);
 175 }
 176
 177 static int
 178 i386_breakpoint_at (CORE_ADDR pc)
 179 {
 180   unsigned char c;
 181
 182   read_inferior_memory (pc, &c, 1);
 183   if (c == 0xCC)
 184     return 1;
 185
 186   return 0;
 187 }
 188
 189 struct linux_target_ops the_low_target = {
 190   i386_num_regs,
 191   i386_regmap,
 192   i386_cannot_fetch_register,
 193   i386_cannot_store_register,
 194   i386_get_pc,
 195   i386_set_pc,
 196   i386_breakpoint,
 197   i386_breakpoint_len,
 198   NULL,
 199   1,
 200   i386_breakpoint_at,
 201 };