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 protected:
  31
  32   void low_arch_setup () override;
  33
  34   bool low_cannot_fetch_register (int regno) override;
  35
  36   bool low_cannot_store_register (int regno) override;
  37
  38   bool low_supports_breakpoints () override;
  39
  40   CORE_ADDR low_get_pc (regcache *regcache) override;
  41
  42   void low_set_pc (regcache *regcache, CORE_ADDR newpc) override;
  43 };
  44
  45 /* The singleton target ops object.  */
  46
  47 static m68k_target the_m68k_target;
  48
  49 bool
  50 m68k_target::low_supports_breakpoints ()
  51 {
  52   return true;
  53 }
  54
  55 CORE_ADDR
  56 m68k_target::low_get_pc (regcache *regcache)
  57 {
  58   return linux_get_pc_32bit (regcache);
  59 }
  60
  61 void
  62 m68k_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
  63 {
  64   linux_set_pc_32bit (regcache, pc);
  65 }
  66
  67 /* Defined in auto-generated file reg-m68k.c.  */
  68 void init_registers_m68k (void);
  69 extern const struct target_desc *tdesc_m68k;
  70
  71 #ifdef HAVE_SYS_REG_H
  72 #include <sys/reg.h>
  73 #endif
  74
  75 #define m68k_num_regs 29
  76 #define m68k_num_gregs 18
  77
  78 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  79 static int m68k_regmap[] =
  80 {
  81 #ifdef PT_D0
  82   PT_D0 * 4, PT_D1 * 4, PT_D2 * 4, PT_D3 * 4,
  83   PT_D4 * 4, PT_D5 * 4, PT_D6 * 4, PT_D7 * 4,
  84   PT_A0 * 4, PT_A1 * 4, PT_A2 * 4, PT_A3 * 4,
  85   PT_A4 * 4, PT_A5 * 4, PT_A6 * 4, PT_USP * 4,
  86   PT_SR * 4, PT_PC * 4,
  87 #else
  88   14 * 4, 0 * 4, 1 * 4, 2 * 4, 3 * 4, 4 * 4, 5 * 4, 6 * 4,
  89   7 * 4, 8 * 4, 9 * 4, 10 * 4, 11 * 4, 12 * 4, 13 * 4, 15 * 4,
  90   17 * 4, 18 * 4,
  91 #endif
  92 #ifdef PT_FP0
  93   PT_FP0 * 4, PT_FP1 * 4, PT_FP2 * 4, PT_FP3 * 4,
  94   PT_FP4 * 4, PT_FP5 * 4, PT_FP6 * 4, PT_FP7 * 4,
  95   PT_FPCR * 4, PT_FPSR * 4, PT_FPIAR * 4
  96 #else
  97   21 * 4, 24 * 4, 27 * 4, 30 * 4, 33 * 4, 36 * 4,
  98   39 * 4, 42 * 4, 45 * 4, 46 * 4, 47 * 4
  99 #endif
 100 };
 101
 102 bool
 103 m68k_target::low_cannot_store_register (int regno)
 104 {
 105   return (regno >= m68k_num_regs);
 106 }
 107
 108 bool
 109 m68k_target::low_cannot_fetch_register (int regno)
 110 {
 111   return (regno >= m68k_num_regs);
 112 }
 113
 114 #ifdef HAVE_PTRACE_GETREGS
 115 #include <sys/procfs.h>
 116 #include "nat/gdb_ptrace.h"
 117
 118 static void
 119 m68k_fill_gregset (struct regcache *regcache, void *buf)
 120 {
 121   int i;
 122
 123   for (i = 0; i < m68k_num_gregs; i++)
 124     collect_register (regcache, i, (char *) buf + m68k_regmap[i]);
 125 }
 126
 127 static void
 128 m68k_store_gregset (struct regcache *regcache, const void *buf)
 129 {
 130   int i;
 131
 132   for (i = 0; i < m68k_num_gregs; i++)
 133     supply_register (regcache, i, (const char *) buf + m68k_regmap[i]);
 134 }
 135
 136 static void
 137 m68k_fill_fpregset (struct regcache *regcache, void *buf)
 138 {
 139   int i;
 140
 141   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 142     collect_register (regcache, i, ((char *) buf
 143                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 144 }
 145
 146 static void
 147 m68k_store_fpregset (struct regcache *regcache, const void *buf)
 148 {
 149   int i;
 150
 151   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 152     supply_register (regcache, i, ((const char *) buf
 153                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 154 }
 155
 156 #endif /* HAVE_PTRACE_GETREGS */
 157
 158 static struct regset_info m68k_regsets[] = {
 159 #ifdef HAVE_PTRACE_GETREGS
 160   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 161     GENERAL_REGS,
 162     m68k_fill_gregset, m68k_store_gregset },
 163   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 164     FP_REGS,
 165     m68k_fill_fpregset, m68k_store_fpregset },
 166 #endif /* HAVE_PTRACE_GETREGS */
 167   NULL_REGSET
 168 };
 169
 170 static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 171 #define m68k_breakpoint_len 2
 172
 173 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 174
 175 static const gdb_byte *
 176 m68k_sw_breakpoint_from_kind (int kind, int *size)
 177 {
 178   *size = m68k_breakpoint_len;
 179   return m68k_breakpoint;
 180 }
 181
 182 static int
 183 m68k_breakpoint_at (CORE_ADDR pc)
 184 {
 185   unsigned char c[2];
 186
 187   read_inferior_memory (pc, c, 2);
 188   if (c[0] == 0x4E && c[1] == 0x4F)
 189     return 1;
 190
 191   return 0;
 192 }
 193
 194 #include <asm/ptrace.h>
 195
 196 #ifdef PTRACE_GET_THREAD_AREA
 197 /* Fetch the thread-local storage pointer for libthread_db.  */
 198
 199 ps_err_e
 200 ps_get_thread_area (struct ps_prochandle *ph,
 201                     lwpid_t lwpid, int idx, void **base)
 202 {
 203   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 204     return PS_ERR;
 205
 206   /* IDX is the bias from the thread pointer to the beginning of the
 207      thread descriptor.  It has to be subtracted due to implementation
 208      quirks in libthread_db.  */
 209   *base = (void *) ((char *)*base - idx);
 210
 211   return PS_OK;
 212 }
 213 #endif /* PTRACE_GET_THREAD_AREA */
 214
 215 static struct regsets_info m68k_regsets_info =
 216   {
 217     m68k_regsets, /* regsets */
 218     0, /* num_regsets */
 219     NULL, /* disabled_regsets */
 220   };
 221
 222 static struct usrregs_info m68k_usrregs_info =
 223   {
 224     m68k_num_regs,
 225     m68k_regmap,
 226   };
 227
 228 static struct regs_info myregs_info =
 229   {
 230     NULL, /* regset_bitmap */
 231     &m68k_usrregs_info,
 232     &m68k_regsets_info
 233   };
 234
 235 const regs_info *
 236 m68k_target::get_regs_info ()
 237 {
 238   return &myregs_info;
 239 }
 240
 241 void
 242 m68k_target::low_arch_setup ()
 243 {
 244   current_process ()->tdesc = tdesc_m68k;
 245 }
 246
 247 /* Support for hardware single step.  */
 248
 249 static int
 250 m68k_supports_hardware_single_step (void)
 251 {
 252   return 1;
 253 }
 254
 255 struct linux_target_ops the_low_target = {
 256   m68k_sw_breakpoint_from_kind,
 257   NULL,
 258   2,
 259   m68k_breakpoint_at,
 260   NULL, /* supports_z_point_type */
 261   NULL, /* insert_point */
 262   NULL, /* remove_point */
 263   NULL, /* stopped_by_watchpoint */
 264   NULL, /* stopped_data_address */
 265   NULL, /* collect_ptrace_register */
 266   NULL, /* supply_ptrace_register */
 267   NULL, /* siginfo_fixup */
 268   NULL, /* new_process */
 269   NULL, /* delete_process */
 270   NULL, /* new_thread */
 271   NULL, /* delete_thread */
 272   NULL, /* new_fork */
 273   NULL, /* prepare_to_resume */
 274   NULL, /* process_qsupported */
 275   NULL, /* supports_tracepoints */
 276   NULL, /* get_thread_area */
 277   NULL, /* install_fast_tracepoint_jump_pad */
 278   NULL, /* emit_ops */
 279   NULL, /* get_min_fast_tracepoint_insn_len */
 280   NULL, /* supports_range_stepping */
 281   m68k_supports_hardware_single_step,
 282 };
 283
 284 /* The linux target ops object.  */
 285
 286 linux_process_target *the_linux_target = &the_m68k_target;
 287
 288 void
 289 initialize_low_arch (void)
 290 {
 291   /* Initialize the Linux target descriptions.  */
 292   init_registers_m68k ();
 293
 294   initialize_regsets_info (&m68k_regsets_info);
 295 }