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