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   const regs_info *get_regs_info () override;
  29
  30   const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
  31
  32 protected:
  33
  34   void low_arch_setup () override;
  35
  36   bool low_cannot_fetch_register (int regno) override;
  37
  38   bool low_cannot_store_register (int regno) override;
  39
  40   bool low_supports_breakpoints () override;
  41
  42   CORE_ADDR low_get_pc (regcache *regcache) override;
  43
  44   void low_set_pc (regcache *regcache, CORE_ADDR newpc) override;
  45 };
  46
  47 /* The singleton target ops object.  */
  48
  49 static m68k_target the_m68k_target;
  50
  51 bool
  52 m68k_target::low_supports_breakpoints ()
  53 {
  54   return true;
  55 }
  56
  57 CORE_ADDR
  58 m68k_target::low_get_pc (regcache *regcache)
  59 {
  60   return linux_get_pc_32bit (regcache);
  61 }
  62
  63 void
  64 m68k_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
  65 {
  66   linux_set_pc_32bit (regcache, pc);
  67 }
  68
  69 /* Defined in auto-generated file reg-m68k.c.  */
  70 void init_registers_m68k (void);
  71 extern const struct target_desc *tdesc_m68k;
  72
  73 #ifdef HAVE_SYS_REG_H
  74 #include <sys/reg.h>
  75 #endif
  76
  77 #define m68k_num_regs 29
  78 #define m68k_num_gregs 18
  79
  80 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  81 static int m68k_regmap[] =
  82 {
  83 #ifdef PT_D0
  84   PT_D0 * 4, PT_D1 * 4, PT_D2 * 4, PT_D3 * 4,
  85   PT_D4 * 4, PT_D5 * 4, PT_D6 * 4, PT_D7 * 4,
  86   PT_A0 * 4, PT_A1 * 4, PT_A2 * 4, PT_A3 * 4,
  87   PT_A4 * 4, PT_A5 * 4, PT_A6 * 4, PT_USP * 4,
  88   PT_SR * 4, PT_PC * 4,
  89 #else
  90   14 * 4, 0 * 4, 1 * 4, 2 * 4, 3 * 4, 4 * 4, 5 * 4, 6 * 4,
  91   7 * 4, 8 * 4, 9 * 4, 10 * 4, 11 * 4, 12 * 4, 13 * 4, 15 * 4,
  92   17 * 4, 18 * 4,
  93 #endif
  94 #ifdef PT_FP0
  95   PT_FP0 * 4, PT_FP1 * 4, PT_FP2 * 4, PT_FP3 * 4,
  96   PT_FP4 * 4, PT_FP5 * 4, PT_FP6 * 4, PT_FP7 * 4,
  97   PT_FPCR * 4, PT_FPSR * 4, PT_FPIAR * 4
  98 #else
  99   21 * 4, 24 * 4, 27 * 4, 30 * 4, 33 * 4, 36 * 4,
 100   39 * 4, 42 * 4, 45 * 4, 46 * 4, 47 * 4
 101 #endif
 102 };
 103
 104 bool
 105 m68k_target::low_cannot_store_register (int regno)
 106 {
 107   return (regno >= m68k_num_regs);
 108 }
 109
 110 bool
 111 m68k_target::low_cannot_fetch_register (int regno)
 112 {
 113   return (regno >= m68k_num_regs);
 114 }
 115
 116 #ifdef HAVE_PTRACE_GETREGS
 117 #include <sys/procfs.h>
 118 #include "nat/gdb_ptrace.h"
 119
 120 static void
 121 m68k_fill_gregset (struct regcache *regcache, void *buf)
 122 {
 123   int i;
 124
 125   for (i = 0; i < m68k_num_gregs; i++)
 126     collect_register (regcache, i, (char *) buf + m68k_regmap[i]);
 127 }
 128
 129 static void
 130 m68k_store_gregset (struct regcache *regcache, const void *buf)
 131 {
 132   int i;
 133
 134   for (i = 0; i < m68k_num_gregs; i++)
 135     supply_register (regcache, i, (const char *) buf + m68k_regmap[i]);
 136 }
 137
 138 static void
 139 m68k_fill_fpregset (struct regcache *regcache, void *buf)
 140 {
 141   int i;
 142
 143   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 144     collect_register (regcache, i, ((char *) buf
 145                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 146 }
 147
 148 static void
 149 m68k_store_fpregset (struct regcache *regcache, const void *buf)
 150 {
 151   int i;
 152
 153   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 154     supply_register (regcache, i, ((const char *) buf
 155                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 156 }
 157
 158 #endif /* HAVE_PTRACE_GETREGS */
 159
 160 static struct regset_info m68k_regsets[] = {
 161 #ifdef HAVE_PTRACE_GETREGS
 162   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 163     GENERAL_REGS,
 164     m68k_fill_gregset, m68k_store_gregset },
 165   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 166     FP_REGS,
 167     m68k_fill_fpregset, m68k_store_fpregset },
 168 #endif /* HAVE_PTRACE_GETREGS */
 169   NULL_REGSET
 170 };
 171
 172 static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 173 #define m68k_breakpoint_len 2
 174
 175 /* Implementation of target ops method "sw_breakpoint_from_kind".  */
 176
 177 const gdb_byte *
 178 m68k_target::sw_breakpoint_from_kind (int kind, int *size)
 179 {
 180   *size = m68k_breakpoint_len;
 181   return m68k_breakpoint;
 182 }
 183
 184 static int
 185 m68k_breakpoint_at (CORE_ADDR pc)
 186 {
 187   unsigned char c[2];
 188
 189   read_inferior_memory (pc, c, 2);
 190   if (c[0] == 0x4E && c[1] == 0x4F)
 191     return 1;
 192
 193   return 0;
 194 }
 195
 196 #include <asm/ptrace.h>
 197
 198 #ifdef PTRACE_GET_THREAD_AREA
 199 /* Fetch the thread-local storage pointer for libthread_db.  */
 200
 201 ps_err_e
 202 ps_get_thread_area (struct ps_prochandle *ph,
 203                     lwpid_t lwpid, int idx, void **base)
 204 {
 205   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 206     return PS_ERR;
 207
 208   /* IDX is the bias from the thread pointer to the beginning of the
 209      thread descriptor.  It has to be subtracted due to implementation
 210      quirks in libthread_db.  */
 211   *base = (void *) ((char *)*base - idx);
 212
 213   return PS_OK;
 214 }
 215 #endif /* PTRACE_GET_THREAD_AREA */
 216
 217 static struct regsets_info m68k_regsets_info =
 218   {
 219     m68k_regsets, /* regsets */
 220     0, /* num_regsets */
 221     NULL, /* disabled_regsets */
 222   };
 223
 224 static struct usrregs_info m68k_usrregs_info =
 225   {
 226     m68k_num_regs,
 227     m68k_regmap,
 228   };
 229
 230 static struct regs_info myregs_info =
 231   {
 232     NULL, /* regset_bitmap */
 233     &m68k_usrregs_info,
 234     &m68k_regsets_info
 235   };
 236
 237 const regs_info *
 238 m68k_target::get_regs_info ()
 239 {
 240   return &myregs_info;
 241 }
 242
 243 void
 244 m68k_target::low_arch_setup ()
 245 {
 246   current_process ()->tdesc = tdesc_m68k;
 247 }
 248
 249 /* Support for hardware single step.  */
 250
 251 static int
 252 m68k_supports_hardware_single_step (void)
 253 {
 254   return 1;
 255 }
 256
 257 struct linux_target_ops the_low_target = {
 258   NULL,
 259   2,
 260   m68k_breakpoint_at,
 261   NULL, /* supports_z_point_type */
 262   NULL, /* insert_point */
 263   NULL, /* remove_point */
 264   NULL, /* stopped_by_watchpoint */
 265   NULL, /* stopped_data_address */
 266   NULL, /* collect_ptrace_register */
 267   NULL, /* supply_ptrace_register */
 268   NULL, /* siginfo_fixup */
 269   NULL, /* new_process */
 270   NULL, /* delete_process */
 271   NULL, /* new_thread */
 272   NULL, /* delete_thread */
 273   NULL, /* new_fork */
 274   NULL, /* prepare_to_resume */
 275   NULL, /* process_qsupported */
 276   NULL, /* supports_tracepoints */
 277   NULL, /* get_thread_area */
 278   NULL, /* install_fast_tracepoint_jump_pad */
 279   NULL, /* emit_ops */
 280   NULL, /* get_min_fast_tracepoint_insn_len */
 281   NULL, /* supports_range_stepping */
 282   m68k_supports_hardware_single_step,
 283 };
 284
 285 /* The linux target ops object.  */
 286
 287 linux_process_target *the_linux_target = &the_m68k_target;
 288
 289 void
 290 initialize_low_arch (void)
 291 {
 292   /* Initialize the Linux target descriptions.  */
 293   init_registers_m68k ();
 294
 295   initialize_regsets_info (&m68k_regsets_info);
 296 }