gdbserver/linux-m68k-low.cc

   1 /* GNU/Linux/m68k specific low level interface, for the remote server for GDB.
   2    Copyright (C) 1995-2020 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include "server.h"
  20 #include "linux-low.h"
  21
  22 /* Linux target op definitions for the m68k architecture.  */
  23
  24 class m68k_target : public linux_process_target
  25 {
  26 public:
  27
  28 };
  29
  30 /* The singleton target ops object.  */
  31
  32 static m68k_target the_m68k_target;
  33
  34 /* Defined in auto-generated file reg-m68k.c.  */
  35 void init_registers_m68k (void);
  36 extern const struct target_desc *tdesc_m68k;
  37
  38 #ifdef HAVE_SYS_REG_H
  39 #include <sys/reg.h>
  40 #endif
  41
  42 #define m68k_num_regs 29
  43 #define m68k_num_gregs 18
  44
  45 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  46 static int m68k_regmap[] =
  47 {
  48 #ifdef PT_D0
  49   PT_D0 * 4, PT_D1 * 4, PT_D2 * 4, PT_D3 * 4,
  50   PT_D4 * 4, PT_D5 * 4, PT_D6 * 4, PT_D7 * 4,
  51   PT_A0 * 4, PT_A1 * 4, PT_A2 * 4, PT_A3 * 4,
  52   PT_A4 * 4, PT_A5 * 4, PT_A6 * 4, PT_USP * 4,
  53   PT_SR * 4, PT_PC * 4,
  54 #else
  55   14 * 4, 0 * 4, 1 * 4, 2 * 4, 3 * 4, 4 * 4, 5 * 4, 6 * 4,
  56   7 * 4, 8 * 4, 9 * 4, 10 * 4, 11 * 4, 12 * 4, 13 * 4, 15 * 4,
  57   17 * 4, 18 * 4,
  58 #endif
  59 #ifdef PT_FP0
  60   PT_FP0 * 4, PT_FP1 * 4, PT_FP2 * 4, PT_FP3 * 4,
  61   PT_FP4 * 4, PT_FP5 * 4, PT_FP6 * 4, PT_FP7 * 4,
  62   PT_FPCR * 4, PT_FPSR * 4, PT_FPIAR * 4
  63 #else
  64   21 * 4, 24 * 4, 27 * 4, 30 * 4, 33 * 4, 36 * 4,
  65   39 * 4, 42 * 4, 45 * 4, 46 * 4, 47 * 4
  66 #endif
  67 };
  68
  69 static int
  70 m68k_cannot_store_register (int regno)
  71 {
  72   return (regno >= m68k_num_regs);
  73 }
  74
  75 static int
  76 m68k_cannot_fetch_register (int regno)
  77 {
  78   return (regno >= m68k_num_regs);
  79 }
  80
  81 #ifdef HAVE_PTRACE_GETREGS
  82 #include <sys/procfs.h>
  83 #include "nat/gdb_ptrace.h"
  84
  85 static void
  86 m68k_fill_gregset (struct regcache *regcache, void *buf)
  87 {
  88   int i;
  89
  90   for (i = 0; i < m68k_num_gregs; i++)
  91     collect_register (regcache, i, (char *) buf + m68k_regmap[i]);
  92 }
  93
  94 static void
  95 m68k_store_gregset (struct regcache *regcache, const void *buf)
  96 {
  97   int i;
  98
  99   for (i = 0; i < m68k_num_gregs; i++)
 100     supply_register (regcache, i, (const char *) buf + m68k_regmap[i]);
 101 }
 102
 103 static void
 104 m68k_fill_fpregset (struct regcache *regcache, void *buf)
 105 {
 106   int i;
 107
 108   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 109     collect_register (regcache, i, ((char *) buf
 110                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 111 }
 112
 113 static void
 114 m68k_store_fpregset (struct regcache *regcache, const void *buf)
 115 {
 116   int i;
 117
 118   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 119     supply_register (regcache, i, ((const char *) buf
 120                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 121 }
 122
 123 #endif /* HAVE_PTRACE_GETREGS */
 124
 125 static struct regset_info m68k_regsets[] = {
 126 #ifdef HAVE_PTRACE_GETREGS
 127   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 128     GENERAL_REGS,
 129     m68k_fill_gregset, m68k_store_gregset },
 130   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 131     FP_REGS,
 132     m68k_fill_fpregset, m68k_store_fpregset },
 133 #endif /* HAVE_PTRACE_GETREGS */
 134   NULL_REGSET
 135 };
 136
 137 static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 138 #define m68k_breakpoint_len 2
 139
 140 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 141
 142 static const gdb_byte *
 143 m68k_sw_breakpoint_from_kind (int kind, int *size)
 144 {
 145   *size = m68k_breakpoint_len;
 146   return m68k_breakpoint;
 147 }
 148
 149 static int
 150 m68k_breakpoint_at (CORE_ADDR pc)
 151 {
 152   unsigned char c[2];
 153
 154   read_inferior_memory (pc, c, 2);
 155   if (c[0] == 0x4E && c[1] == 0x4F)
 156     return 1;
 157
 158   return 0;
 159 }
 160
 161 #include <asm/ptrace.h>
 162
 163 #ifdef PTRACE_GET_THREAD_AREA
 164 /* Fetch the thread-local storage pointer for libthread_db.  */
 165
 166 ps_err_e
 167 ps_get_thread_area (struct ps_prochandle *ph,
 168                     lwpid_t lwpid, int idx, void **base)
 169 {
 170   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 171     return PS_ERR;
 172
 173   /* IDX is the bias from the thread pointer to the beginning of the
 174      thread descriptor.  It has to be subtracted due to implementation
 175      quirks in libthread_db.  */
 176   *base = (void *) ((char *)*base - idx);
 177
 178   return PS_OK;
 179 }
 180 #endif /* PTRACE_GET_THREAD_AREA */
 181
 182 static struct regsets_info m68k_regsets_info =
 183   {
 184     m68k_regsets, /* regsets */
 185     0, /* num_regsets */
 186     NULL, /* disabled_regsets */
 187   };
 188
 189 static struct usrregs_info m68k_usrregs_info =
 190   {
 191     m68k_num_regs,
 192     m68k_regmap,
 193   };
 194
 195 static struct regs_info regs_info =
 196   {
 197     NULL, /* regset_bitmap */
 198     &m68k_usrregs_info,
 199     &m68k_regsets_info
 200   };
 201
 202 static const struct regs_info *
 203 m68k_regs_info (void)
 204 {
 205   return &regs_info;
 206 }
 207
 208 static void
 209 m68k_arch_setup (void)
 210 {
 211   current_process ()->tdesc = tdesc_m68k;
 212 }
 213
 214 /* Support for hardware single step.  */
 215
 216 static int
 217 m68k_supports_hardware_single_step (void)
 218 {
 219   return 1;
 220 }
 221
 222 struct linux_target_ops the_low_target = {
 223   m68k_arch_setup,
 224   m68k_regs_info,
 225   m68k_cannot_fetch_register,
 226   m68k_cannot_store_register,
 227   NULL, /* fetch_register */
 228   linux_get_pc_32bit,
 229   linux_set_pc_32bit,
 230   NULL, /* breakpoint_kind_from_pc */
 231   m68k_sw_breakpoint_from_kind,
 232   NULL,
 233   2,
 234   m68k_breakpoint_at,
 235   NULL, /* supports_z_point_type */
 236   NULL, /* insert_point */
 237   NULL, /* remove_point */
 238   NULL, /* stopped_by_watchpoint */
 239   NULL, /* stopped_data_address */
 240   NULL, /* collect_ptrace_register */
 241   NULL, /* supply_ptrace_register */
 242   NULL, /* siginfo_fixup */
 243   NULL, /* new_process */
 244   NULL, /* delete_process */
 245   NULL, /* new_thread */
 246   NULL, /* delete_thread */
 247   NULL, /* new_fork */
 248   NULL, /* prepare_to_resume */
 249   NULL, /* process_qsupported */
 250   NULL, /* supports_tracepoints */
 251   NULL, /* get_thread_area */
 252   NULL, /* install_fast_tracepoint_jump_pad */
 253   NULL, /* emit_ops */
 254   NULL, /* get_min_fast_tracepoint_insn_len */
 255   NULL, /* supports_range_stepping */
 256   NULL, /* breakpoint_kind_from_current_state */
 257   m68k_supports_hardware_single_step,
 258 };
 259
 260 /* The linux target ops object.  */
 261
 262 linux_process_target *the_linux_target = &the_m68k_target;
 263
 264 void
 265 initialize_low_arch (void)
 266 {
 267   /* Initialize the Linux target descriptions.  */
 268   init_registers_m68k ();
 269
 270   initialize_regsets_info (&m68k_regsets_info);
 271 }