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   int low_decr_pc_after_break () override;
  47 };
  48
  49 /* The singleton target ops object.  */
  50
  51 static m68k_target the_m68k_target;
  52
  53 bool
  54 m68k_target::low_supports_breakpoints ()
  55 {
  56   return true;
  57 }
  58
  59 CORE_ADDR
  60 m68k_target::low_get_pc (regcache *regcache)
  61 {
  62   return linux_get_pc_32bit (regcache);
  63 }
  64
  65 void
  66 m68k_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
  67 {
  68   linux_set_pc_32bit (regcache, pc);
  69 }
  70
  71 int
  72 m68k_target::low_decr_pc_after_break ()
  73 {
  74   return 2;
  75 }
  76
  77 /* Defined in auto-generated file reg-m68k.c.  */
  78 void init_registers_m68k (void);
  79 extern const struct target_desc *tdesc_m68k;
  80
  81 #ifdef HAVE_SYS_REG_H
  82 #include <sys/reg.h>
  83 #endif
  84
  85 #define m68k_num_regs 29
  86 #define m68k_num_gregs 18
  87
  88 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  89 static int m68k_regmap[] =
  90 {
  91 #ifdef PT_D0
  92   PT_D0 * 4, PT_D1 * 4, PT_D2 * 4, PT_D3 * 4,
  93   PT_D4 * 4, PT_D5 * 4, PT_D6 * 4, PT_D7 * 4,
  94   PT_A0 * 4, PT_A1 * 4, PT_A2 * 4, PT_A3 * 4,
  95   PT_A4 * 4, PT_A5 * 4, PT_A6 * 4, PT_USP * 4,
  96   PT_SR * 4, PT_PC * 4,
  97 #else
  98   14 * 4, 0 * 4, 1 * 4, 2 * 4, 3 * 4, 4 * 4, 5 * 4, 6 * 4,
  99   7 * 4, 8 * 4, 9 * 4, 10 * 4, 11 * 4, 12 * 4, 13 * 4, 15 * 4,
 100   17 * 4, 18 * 4,
 101 #endif
 102 #ifdef PT_FP0
 103   PT_FP0 * 4, PT_FP1 * 4, PT_FP2 * 4, PT_FP3 * 4,
 104   PT_FP4 * 4, PT_FP5 * 4, PT_FP6 * 4, PT_FP7 * 4,
 105   PT_FPCR * 4, PT_FPSR * 4, PT_FPIAR * 4
 106 #else
 107   21 * 4, 24 * 4, 27 * 4, 30 * 4, 33 * 4, 36 * 4,
 108   39 * 4, 42 * 4, 45 * 4, 46 * 4, 47 * 4
 109 #endif
 110 };
 111
 112 bool
 113 m68k_target::low_cannot_store_register (int regno)
 114 {
 115   return (regno >= m68k_num_regs);
 116 }
 117
 118 bool
 119 m68k_target::low_cannot_fetch_register (int regno)
 120 {
 121   return (regno >= m68k_num_regs);
 122 }
 123
 124 #ifdef HAVE_PTRACE_GETREGS
 125 #include <sys/procfs.h>
 126 #include "nat/gdb_ptrace.h"
 127
 128 static void
 129 m68k_fill_gregset (struct regcache *regcache, void *buf)
 130 {
 131   int i;
 132
 133   for (i = 0; i < m68k_num_gregs; i++)
 134     collect_register (regcache, i, (char *) buf + m68k_regmap[i]);
 135 }
 136
 137 static void
 138 m68k_store_gregset (struct regcache *regcache, const void *buf)
 139 {
 140   int i;
 141
 142   for (i = 0; i < m68k_num_gregs; i++)
 143     supply_register (regcache, i, (const char *) buf + m68k_regmap[i]);
 144 }
 145
 146 static void
 147 m68k_fill_fpregset (struct regcache *regcache, void *buf)
 148 {
 149   int i;
 150
 151   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 152     collect_register (regcache, i, ((char *) buf
 153                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 154 }
 155
 156 static void
 157 m68k_store_fpregset (struct regcache *regcache, const void *buf)
 158 {
 159   int i;
 160
 161   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 162     supply_register (regcache, i, ((const char *) buf
 163                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 164 }
 165
 166 #endif /* HAVE_PTRACE_GETREGS */
 167
 168 static struct regset_info m68k_regsets[] = {
 169 #ifdef HAVE_PTRACE_GETREGS
 170   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 171     GENERAL_REGS,
 172     m68k_fill_gregset, m68k_store_gregset },
 173   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 174     FP_REGS,
 175     m68k_fill_fpregset, m68k_store_fpregset },
 176 #endif /* HAVE_PTRACE_GETREGS */
 177   NULL_REGSET
 178 };
 179
 180 static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 181 #define m68k_breakpoint_len 2
 182
 183 /* Implementation of target ops method "sw_breakpoint_from_kind".  */
 184
 185 const gdb_byte *
 186 m68k_target::sw_breakpoint_from_kind (int kind, int *size)
 187 {
 188   *size = m68k_breakpoint_len;
 189   return m68k_breakpoint;
 190 }
 191
 192 static int
 193 m68k_breakpoint_at (CORE_ADDR pc)
 194 {
 195   unsigned char c[2];
 196
 197   read_inferior_memory (pc, c, 2);
 198   if (c[0] == 0x4E && c[1] == 0x4F)
 199     return 1;
 200
 201   return 0;
 202 }
 203
 204 #include <asm/ptrace.h>
 205
 206 #ifdef PTRACE_GET_THREAD_AREA
 207 /* Fetch the thread-local storage pointer for libthread_db.  */
 208
 209 ps_err_e
 210 ps_get_thread_area (struct ps_prochandle *ph,
 211                     lwpid_t lwpid, int idx, void **base)
 212 {
 213   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 214     return PS_ERR;
 215
 216   /* IDX is the bias from the thread pointer to the beginning of the
 217      thread descriptor.  It has to be subtracted due to implementation
 218      quirks in libthread_db.  */
 219   *base = (void *) ((char *)*base - idx);
 220
 221   return PS_OK;
 222 }
 223 #endif /* PTRACE_GET_THREAD_AREA */
 224
 225 static struct regsets_info m68k_regsets_info =
 226   {
 227     m68k_regsets, /* regsets */
 228     0, /* num_regsets */
 229     NULL, /* disabled_regsets */
 230   };
 231
 232 static struct usrregs_info m68k_usrregs_info =
 233   {
 234     m68k_num_regs,
 235     m68k_regmap,
 236   };
 237
 238 static struct regs_info myregs_info =
 239   {
 240     NULL, /* regset_bitmap */
 241     &m68k_usrregs_info,
 242     &m68k_regsets_info
 243   };
 244
 245 const regs_info *
 246 m68k_target::get_regs_info ()
 247 {
 248   return &myregs_info;
 249 }
 250
 251 void
 252 m68k_target::low_arch_setup ()
 253 {
 254   current_process ()->tdesc = tdesc_m68k;
 255 }
 256
 257 /* Support for hardware single step.  */
 258
 259 static int
 260 m68k_supports_hardware_single_step (void)
 261 {
 262   return 1;
 263 }
 264
 265 struct linux_target_ops the_low_target = {
 266   m68k_breakpoint_at,
 267   NULL, /* supports_z_point_type */
 268   NULL, /* insert_point */
 269   NULL, /* remove_point */
 270   NULL, /* stopped_by_watchpoint */
 271   NULL, /* stopped_data_address */
 272   NULL, /* collect_ptrace_register */
 273   NULL, /* supply_ptrace_register */
 274   NULL, /* siginfo_fixup */
 275   NULL, /* new_process */
 276   NULL, /* delete_process */
 277   NULL, /* new_thread */
 278   NULL, /* delete_thread */
 279   NULL, /* new_fork */
 280   NULL, /* prepare_to_resume */
 281   NULL, /* process_qsupported */
 282   NULL, /* supports_tracepoints */
 283   NULL, /* get_thread_area */
 284   NULL, /* install_fast_tracepoint_jump_pad */
 285   NULL, /* emit_ops */
 286   NULL, /* get_min_fast_tracepoint_insn_len */
 287   NULL, /* supports_range_stepping */
 288   m68k_supports_hardware_single_step,
 289 };
 290
 291 /* The linux target ops object.  */
 292
 293 linux_process_target *the_linux_target = &the_m68k_target;
 294
 295 void
 296 initialize_low_arch (void)
 297 {
 298   /* Initialize the Linux target descriptions.  */
 299   init_registers_m68k ();
 300
 301   initialize_regsets_info (&m68k_regsets_info);
 302 }