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
  35 /* The singleton target ops object.  */
  36
  37 static m68k_target the_m68k_target;
  38
  39 /* Defined in auto-generated file reg-m68k.c.  */
  40 void init_registers_m68k (void);
  41 extern const struct target_desc *tdesc_m68k;
  42
  43 #ifdef HAVE_SYS_REG_H
  44 #include <sys/reg.h>
  45 #endif
  46
  47 #define m68k_num_regs 29
  48 #define m68k_num_gregs 18
  49
  50 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  51 static int m68k_regmap[] =
  52 {
  53 #ifdef PT_D0
  54   PT_D0 * 4, PT_D1 * 4, PT_D2 * 4, PT_D3 * 4,
  55   PT_D4 * 4, PT_D5 * 4, PT_D6 * 4, PT_D7 * 4,
  56   PT_A0 * 4, PT_A1 * 4, PT_A2 * 4, PT_A3 * 4,
  57   PT_A4 * 4, PT_A5 * 4, PT_A6 * 4, PT_USP * 4,
  58   PT_SR * 4, PT_PC * 4,
  59 #else
  60   14 * 4, 0 * 4, 1 * 4, 2 * 4, 3 * 4, 4 * 4, 5 * 4, 6 * 4,
  61   7 * 4, 8 * 4, 9 * 4, 10 * 4, 11 * 4, 12 * 4, 13 * 4, 15 * 4,
  62   17 * 4, 18 * 4,
  63 #endif
  64 #ifdef PT_FP0
  65   PT_FP0 * 4, PT_FP1 * 4, PT_FP2 * 4, PT_FP3 * 4,
  66   PT_FP4 * 4, PT_FP5 * 4, PT_FP6 * 4, PT_FP7 * 4,
  67   PT_FPCR * 4, PT_FPSR * 4, PT_FPIAR * 4
  68 #else
  69   21 * 4, 24 * 4, 27 * 4, 30 * 4, 33 * 4, 36 * 4,
  70   39 * 4, 42 * 4, 45 * 4, 46 * 4, 47 * 4
  71 #endif
  72 };
  73
  74 static int
  75 m68k_cannot_store_register (int regno)
  76 {
  77   return (regno >= m68k_num_regs);
  78 }
  79
  80 static int
  81 m68k_cannot_fetch_register (int regno)
  82 {
  83   return (regno >= m68k_num_regs);
  84 }
  85
  86 #ifdef HAVE_PTRACE_GETREGS
  87 #include <sys/procfs.h>
  88 #include "nat/gdb_ptrace.h"
  89
  90 static void
  91 m68k_fill_gregset (struct regcache *regcache, void *buf)
  92 {
  93   int i;
  94
  95   for (i = 0; i < m68k_num_gregs; i++)
  96     collect_register (regcache, i, (char *) buf + m68k_regmap[i]);
  97 }
  98
  99 static void
 100 m68k_store_gregset (struct regcache *regcache, const void *buf)
 101 {
 102   int i;
 103
 104   for (i = 0; i < m68k_num_gregs; i++)
 105     supply_register (regcache, i, (const char *) buf + m68k_regmap[i]);
 106 }
 107
 108 static void
 109 m68k_fill_fpregset (struct regcache *regcache, void *buf)
 110 {
 111   int i;
 112
 113   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 114     collect_register (regcache, i, ((char *) buf
 115                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 116 }
 117
 118 static void
 119 m68k_store_fpregset (struct regcache *regcache, const void *buf)
 120 {
 121   int i;
 122
 123   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 124     supply_register (regcache, i, ((const char *) buf
 125                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 126 }
 127
 128 #endif /* HAVE_PTRACE_GETREGS */
 129
 130 static struct regset_info m68k_regsets[] = {
 131 #ifdef HAVE_PTRACE_GETREGS
 132   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 133     GENERAL_REGS,
 134     m68k_fill_gregset, m68k_store_gregset },
 135   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 136     FP_REGS,
 137     m68k_fill_fpregset, m68k_store_fpregset },
 138 #endif /* HAVE_PTRACE_GETREGS */
 139   NULL_REGSET
 140 };
 141
 142 static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 143 #define m68k_breakpoint_len 2
 144
 145 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 146
 147 static const gdb_byte *
 148 m68k_sw_breakpoint_from_kind (int kind, int *size)
 149 {
 150   *size = m68k_breakpoint_len;
 151   return m68k_breakpoint;
 152 }
 153
 154 static int
 155 m68k_breakpoint_at (CORE_ADDR pc)
 156 {
 157   unsigned char c[2];
 158
 159   read_inferior_memory (pc, c, 2);
 160   if (c[0] == 0x4E && c[1] == 0x4F)
 161     return 1;
 162
 163   return 0;
 164 }
 165
 166 #include <asm/ptrace.h>
 167
 168 #ifdef PTRACE_GET_THREAD_AREA
 169 /* Fetch the thread-local storage pointer for libthread_db.  */
 170
 171 ps_err_e
 172 ps_get_thread_area (struct ps_prochandle *ph,
 173                     lwpid_t lwpid, int idx, void **base)
 174 {
 175   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 176     return PS_ERR;
 177
 178   /* IDX is the bias from the thread pointer to the beginning of the
 179      thread descriptor.  It has to be subtracted due to implementation
 180      quirks in libthread_db.  */
 181   *base = (void *) ((char *)*base - idx);
 182
 183   return PS_OK;
 184 }
 185 #endif /* PTRACE_GET_THREAD_AREA */
 186
 187 static struct regsets_info m68k_regsets_info =
 188   {
 189     m68k_regsets, /* regsets */
 190     0, /* num_regsets */
 191     NULL, /* disabled_regsets */
 192   };
 193
 194 static struct usrregs_info m68k_usrregs_info =
 195   {
 196     m68k_num_regs,
 197     m68k_regmap,
 198   };
 199
 200 static struct regs_info myregs_info =
 201   {
 202     NULL, /* regset_bitmap */
 203     &m68k_usrregs_info,
 204     &m68k_regsets_info
 205   };
 206
 207 const regs_info *
 208 m68k_target::get_regs_info ()
 209 {
 210   return &myregs_info;
 211 }
 212
 213 void
 214 m68k_target::low_arch_setup ()
 215 {
 216   current_process ()->tdesc = tdesc_m68k;
 217 }
 218
 219 /* Support for hardware single step.  */
 220
 221 static int
 222 m68k_supports_hardware_single_step (void)
 223 {
 224   return 1;
 225 }
 226
 227 struct linux_target_ops the_low_target = {
 228   m68k_cannot_fetch_register,
 229   m68k_cannot_store_register,
 230   NULL, /* fetch_register */
 231   linux_get_pc_32bit,
 232   linux_set_pc_32bit,
 233   NULL, /* breakpoint_kind_from_pc */
 234   m68k_sw_breakpoint_from_kind,
 235   NULL,
 236   2,
 237   m68k_breakpoint_at,
 238   NULL, /* supports_z_point_type */
 239   NULL, /* insert_point */
 240   NULL, /* remove_point */
 241   NULL, /* stopped_by_watchpoint */
 242   NULL, /* stopped_data_address */
 243   NULL, /* collect_ptrace_register */
 244   NULL, /* supply_ptrace_register */
 245   NULL, /* siginfo_fixup */
 246   NULL, /* new_process */
 247   NULL, /* delete_process */
 248   NULL, /* new_thread */
 249   NULL, /* delete_thread */
 250   NULL, /* new_fork */
 251   NULL, /* prepare_to_resume */
 252   NULL, /* process_qsupported */
 253   NULL, /* supports_tracepoints */
 254   NULL, /* get_thread_area */
 255   NULL, /* install_fast_tracepoint_jump_pad */
 256   NULL, /* emit_ops */
 257   NULL, /* get_min_fast_tracepoint_insn_len */
 258   NULL, /* supports_range_stepping */
 259   NULL, /* breakpoint_kind_from_current_state */
 260   m68k_supports_hardware_single_step,
 261 };
 262
 263 /* The linux target ops object.  */
 264
 265 linux_process_target *the_linux_target = &the_m68k_target;
 266
 267 void
 268 initialize_low_arch (void)
 269 {
 270   /* Initialize the Linux target descriptions.  */
 271   init_registers_m68k ();
 272
 273   initialize_regsets_info (&m68k_regsets_info);
 274 }