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 protected:
  29
  30   void low_arch_setup () override;
  31 };
  32
  33 /* The singleton target ops object.  */
  34
  35 static m68k_target the_m68k_target;
  36
  37 /* Defined in auto-generated file reg-m68k.c.  */
  38 void init_registers_m68k (void);
  39 extern const struct target_desc *tdesc_m68k;
  40
  41 #ifdef HAVE_SYS_REG_H
  42 #include <sys/reg.h>
  43 #endif
  44
  45 #define m68k_num_regs 29
  46 #define m68k_num_gregs 18
  47
  48 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  49 static int m68k_regmap[] =
  50 {
  51 #ifdef PT_D0
  52   PT_D0 * 4, PT_D1 * 4, PT_D2 * 4, PT_D3 * 4,
  53   PT_D4 * 4, PT_D5 * 4, PT_D6 * 4, PT_D7 * 4,
  54   PT_A0 * 4, PT_A1 * 4, PT_A2 * 4, PT_A3 * 4,
  55   PT_A4 * 4, PT_A5 * 4, PT_A6 * 4, PT_USP * 4,
  56   PT_SR * 4, PT_PC * 4,
  57 #else
  58   14 * 4, 0 * 4, 1 * 4, 2 * 4, 3 * 4, 4 * 4, 5 * 4, 6 * 4,
  59   7 * 4, 8 * 4, 9 * 4, 10 * 4, 11 * 4, 12 * 4, 13 * 4, 15 * 4,
  60   17 * 4, 18 * 4,
  61 #endif
  62 #ifdef PT_FP0
  63   PT_FP0 * 4, PT_FP1 * 4, PT_FP2 * 4, PT_FP3 * 4,
  64   PT_FP4 * 4, PT_FP5 * 4, PT_FP6 * 4, PT_FP7 * 4,
  65   PT_FPCR * 4, PT_FPSR * 4, PT_FPIAR * 4
  66 #else
  67   21 * 4, 24 * 4, 27 * 4, 30 * 4, 33 * 4, 36 * 4,
  68   39 * 4, 42 * 4, 45 * 4, 46 * 4, 47 * 4
  69 #endif
  70 };
  71
  72 static int
  73 m68k_cannot_store_register (int regno)
  74 {
  75   return (regno >= m68k_num_regs);
  76 }
  77
  78 static int
  79 m68k_cannot_fetch_register (int regno)
  80 {
  81   return (regno >= m68k_num_regs);
  82 }
  83
  84 #ifdef HAVE_PTRACE_GETREGS
  85 #include <sys/procfs.h>
  86 #include "nat/gdb_ptrace.h"
  87
  88 static void
  89 m68k_fill_gregset (struct regcache *regcache, void *buf)
  90 {
  91   int i;
  92
  93   for (i = 0; i < m68k_num_gregs; i++)
  94     collect_register (regcache, i, (char *) buf + m68k_regmap[i]);
  95 }
  96
  97 static void
  98 m68k_store_gregset (struct regcache *regcache, const void *buf)
  99 {
 100   int i;
 101
 102   for (i = 0; i < m68k_num_gregs; i++)
 103     supply_register (regcache, i, (const char *) buf + m68k_regmap[i]);
 104 }
 105
 106 static void
 107 m68k_fill_fpregset (struct regcache *regcache, void *buf)
 108 {
 109   int i;
 110
 111   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 112     collect_register (regcache, i, ((char *) buf
 113                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 114 }
 115
 116 static void
 117 m68k_store_fpregset (struct regcache *regcache, const void *buf)
 118 {
 119   int i;
 120
 121   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 122     supply_register (regcache, i, ((const char *) buf
 123                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 124 }
 125
 126 #endif /* HAVE_PTRACE_GETREGS */
 127
 128 static struct regset_info m68k_regsets[] = {
 129 #ifdef HAVE_PTRACE_GETREGS
 130   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 131     GENERAL_REGS,
 132     m68k_fill_gregset, m68k_store_gregset },
 133   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 134     FP_REGS,
 135     m68k_fill_fpregset, m68k_store_fpregset },
 136 #endif /* HAVE_PTRACE_GETREGS */
 137   NULL_REGSET
 138 };
 139
 140 static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 141 #define m68k_breakpoint_len 2
 142
 143 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 144
 145 static const gdb_byte *
 146 m68k_sw_breakpoint_from_kind (int kind, int *size)
 147 {
 148   *size = m68k_breakpoint_len;
 149   return m68k_breakpoint;
 150 }
 151
 152 static int
 153 m68k_breakpoint_at (CORE_ADDR pc)
 154 {
 155   unsigned char c[2];
 156
 157   read_inferior_memory (pc, c, 2);
 158   if (c[0] == 0x4E && c[1] == 0x4F)
 159     return 1;
 160
 161   return 0;
 162 }
 163
 164 #include <asm/ptrace.h>
 165
 166 #ifdef PTRACE_GET_THREAD_AREA
 167 /* Fetch the thread-local storage pointer for libthread_db.  */
 168
 169 ps_err_e
 170 ps_get_thread_area (struct ps_prochandle *ph,
 171                     lwpid_t lwpid, int idx, void **base)
 172 {
 173   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 174     return PS_ERR;
 175
 176   /* IDX is the bias from the thread pointer to the beginning of the
 177      thread descriptor.  It has to be subtracted due to implementation
 178      quirks in libthread_db.  */
 179   *base = (void *) ((char *)*base - idx);
 180
 181   return PS_OK;
 182 }
 183 #endif /* PTRACE_GET_THREAD_AREA */
 184
 185 static struct regsets_info m68k_regsets_info =
 186   {
 187     m68k_regsets, /* regsets */
 188     0, /* num_regsets */
 189     NULL, /* disabled_regsets */
 190   };
 191
 192 static struct usrregs_info m68k_usrregs_info =
 193   {
 194     m68k_num_regs,
 195     m68k_regmap,
 196   };
 197
 198 static struct regs_info regs_info =
 199   {
 200     NULL, /* regset_bitmap */
 201     &m68k_usrregs_info,
 202     &m68k_regsets_info
 203   };
 204
 205 static const struct regs_info *
 206 m68k_regs_info (void)
 207 {
 208   return &regs_info;
 209 }
 210
 211 void
 212 m68k_target::low_arch_setup ()
 213 {
 214   current_process ()->tdesc = tdesc_m68k;
 215 }
 216
 217 /* Support for hardware single step.  */
 218
 219 static int
 220 m68k_supports_hardware_single_step (void)
 221 {
 222   return 1;
 223 }
 224
 225 struct linux_target_ops the_low_target = {
 226   m68k_regs_info,
 227   m68k_cannot_fetch_register,
 228   m68k_cannot_store_register,
 229   NULL, /* fetch_register */
 230   linux_get_pc_32bit,
 231   linux_set_pc_32bit,
 232   NULL, /* breakpoint_kind_from_pc */
 233   m68k_sw_breakpoint_from_kind,
 234   NULL,
 235   2,
 236   m68k_breakpoint_at,
 237   NULL, /* supports_z_point_type */
 238   NULL, /* insert_point */
 239   NULL, /* remove_point */
 240   NULL, /* stopped_by_watchpoint */
 241   NULL, /* stopped_data_address */
 242   NULL, /* collect_ptrace_register */
 243   NULL, /* supply_ptrace_register */
 244   NULL, /* siginfo_fixup */
 245   NULL, /* new_process */
 246   NULL, /* delete_process */
 247   NULL, /* new_thread */
 248   NULL, /* delete_thread */
 249   NULL, /* new_fork */
 250   NULL, /* prepare_to_resume */
 251   NULL, /* process_qsupported */
 252   NULL, /* supports_tracepoints */
 253   NULL, /* get_thread_area */
 254   NULL, /* install_fast_tracepoint_jump_pad */
 255   NULL, /* emit_ops */
 256   NULL, /* get_min_fast_tracepoint_insn_len */
 257   NULL, /* supports_range_stepping */
 258   NULL, /* breakpoint_kind_from_current_state */
 259   m68k_supports_hardware_single_step,
 260 };
 261
 262 /* The linux target ops object.  */
 263
 264 linux_process_target *the_linux_target = &the_m68k_target;
 265
 266 void
 267 initialize_low_arch (void)
 268 {
 269   /* Initialize the Linux target descriptions.  */
 270   init_registers_m68k ();
 271
 272   initialize_regsets_info (&m68k_regsets_info);
 273 }