gdbserver/linux-m68k-low.cc

   1 /* GNU/Linux/m68k specific low level interface, for the remote server for GDB.
   2    Copyright (C) 1995-2024 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 "linux-low.h"
  20
  21 /* Linux target op definitions for the m68k architecture.  */
  22
  23 class m68k_target : public linux_process_target
  24 {
  25 public:
  26
  27   const regs_info *get_regs_info () override;
  28
  29   const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
  30
  31 protected:
  32
  33   void low_arch_setup () override;
  34
  35   bool low_cannot_fetch_register (int regno) override;
  36
  37   bool low_cannot_store_register (int regno) override;
  38
  39   bool low_supports_breakpoints () override;
  40
  41   CORE_ADDR low_get_pc (regcache *regcache) override;
  42
  43   void low_set_pc (regcache *regcache, CORE_ADDR newpc) override;
  44
  45   int low_decr_pc_after_break () override;
  46
  47   bool low_breakpoint_at (CORE_ADDR pc) override;
  48 };
  49
  50 /* The singleton target ops object.  */
  51
  52 static m68k_target the_m68k_target;
  53
  54 bool
  55 m68k_target::low_supports_breakpoints ()
  56 {
  57   return true;
  58 }
  59
  60 CORE_ADDR
  61 m68k_target::low_get_pc (regcache *regcache)
  62 {
  63   return linux_get_pc_32bit (regcache);
  64 }
  65
  66 void
  67 m68k_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
  68 {
  69   linux_set_pc_32bit (regcache, pc);
  70 }
  71
  72 int
  73 m68k_target::low_decr_pc_after_break ()
  74 {
  75   return 2;
  76 }
  77
  78 /* Defined in auto-generated file reg-m68k.c.  */
  79 void init_registers_m68k (void);
  80 extern const struct target_desc *tdesc_m68k;
  81
  82 #ifdef HAVE_SYS_REG_H
  83 #include <sys/reg.h>
  84 #endif
  85
  86 #define m68k_num_regs 29
  87 #define m68k_num_gregs 18
  88
  89 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  90 static int m68k_regmap[] =
  91 {
  92 #ifdef PT_D0
  93   PT_D0 * 4, PT_D1 * 4, PT_D2 * 4, PT_D3 * 4,
  94   PT_D4 * 4, PT_D5 * 4, PT_D6 * 4, PT_D7 * 4,
  95   PT_A0 * 4, PT_A1 * 4, PT_A2 * 4, PT_A3 * 4,
  96   PT_A4 * 4, PT_A5 * 4, PT_A6 * 4, PT_USP * 4,
  97   PT_SR * 4, PT_PC * 4,
  98 #else
  99   14 * 4, 0 * 4, 1 * 4, 2 * 4, 3 * 4, 4 * 4, 5 * 4, 6 * 4,
 100   7 * 4, 8 * 4, 9 * 4, 10 * 4, 11 * 4, 12 * 4, 13 * 4, 15 * 4,
 101   17 * 4, 18 * 4,
 102 #endif
 103 #ifdef PT_FP0
 104   PT_FP0 * 4, PT_FP1 * 4, PT_FP2 * 4, PT_FP3 * 4,
 105   PT_FP4 * 4, PT_FP5 * 4, PT_FP6 * 4, PT_FP7 * 4,
 106   PT_FPCR * 4, PT_FPSR * 4, PT_FPIAR * 4
 107 #else
 108   21 * 4, 24 * 4, 27 * 4, 30 * 4, 33 * 4, 36 * 4,
 109   39 * 4, 42 * 4, 45 * 4, 46 * 4, 47 * 4
 110 #endif
 111 };
 112
 113 bool
 114 m68k_target::low_cannot_store_register (int regno)
 115 {
 116   return (regno >= m68k_num_regs);
 117 }
 118
 119 bool
 120 m68k_target::low_cannot_fetch_register (int regno)
 121 {
 122   return (regno >= m68k_num_regs);
 123 }
 124
 125 #ifdef HAVE_PTRACE_GETREGS
 126 #include <sys/procfs.h>
 127 #include "nat/gdb_ptrace.h"
 128
 129 static void
 130 m68k_fill_gregset (struct regcache *regcache, void *buf)
 131 {
 132   int i;
 133
 134   for (i = 0; i < m68k_num_gregs; i++)
 135     collect_register (regcache, i, (char *) buf + m68k_regmap[i]);
 136 }
 137
 138 static void
 139 m68k_store_gregset (struct regcache *regcache, const void *buf)
 140 {
 141   int i;
 142
 143   for (i = 0; i < m68k_num_gregs; i++)
 144     supply_register (regcache, i, (const char *) buf + m68k_regmap[i]);
 145 }
 146
 147 static void
 148 m68k_fill_fpregset (struct regcache *regcache, void *buf)
 149 {
 150   int i;
 151
 152   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 153     collect_register (regcache, i, ((char *) buf
 154                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 155 }
 156
 157 static void
 158 m68k_store_fpregset (struct regcache *regcache, const void *buf)
 159 {
 160   int i;
 161
 162   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 163     supply_register (regcache, i, ((const char *) buf
 164                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 165 }
 166
 167 #endif /* HAVE_PTRACE_GETREGS */
 168
 169 static struct regset_info m68k_regsets[] = {
 170 #ifdef HAVE_PTRACE_GETREGS
 171   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 172     GENERAL_REGS,
 173     m68k_fill_gregset, m68k_store_gregset },
 174   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 175     FP_REGS,
 176     m68k_fill_fpregset, m68k_store_fpregset },
 177 #endif /* HAVE_PTRACE_GETREGS */
 178   NULL_REGSET
 179 };
 180
 181 static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 182 #define m68k_breakpoint_len 2
 183
 184 /* Implementation of target ops method "sw_breakpoint_from_kind".  */
 185
 186 const gdb_byte *
 187 m68k_target::sw_breakpoint_from_kind (int kind, int *size)
 188 {
 189   *size = m68k_breakpoint_len;
 190   return m68k_breakpoint;
 191 }
 192
 193 bool
 194 m68k_target::low_breakpoint_at (CORE_ADDR pc)
 195 {
 196   unsigned char c[2];
 197
 198   read_inferior_memory (pc, c, 2);
 199   if (c[0] == 0x4E && c[1] == 0x4F)
 200     return true;
 201
 202   return false;
 203 }
 204
 205 #include <asm/ptrace.h>
 206
 207 #ifdef PTRACE_GET_THREAD_AREA
 208 /* Fetch the thread-local storage pointer for libthread_db.  */
 209
 210 ps_err_e
 211 ps_get_thread_area (struct ps_prochandle *ph,
 212                     lwpid_t lwpid, int idx, void **base)
 213 {
 214   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 215     return PS_ERR;
 216
 217   /* IDX is the bias from the thread pointer to the beginning of the
 218      thread descriptor.  It has to be subtracted due to implementation
 219      quirks in libthread_db.  */
 220   *base = (void *) ((char *)*base - idx);
 221
 222   return PS_OK;
 223 }
 224 #endif /* PTRACE_GET_THREAD_AREA */
 225
 226 static struct regsets_info m68k_regsets_info =
 227   {
 228     m68k_regsets, /* regsets */
 229     0, /* num_regsets */
 230     NULL, /* disabled_regsets */
 231   };
 232
 233 static struct usrregs_info m68k_usrregs_info =
 234   {
 235     m68k_num_regs,
 236     m68k_regmap,
 237   };
 238
 239 static struct regs_info myregs_info =
 240   {
 241     NULL, /* regset_bitmap */
 242     &m68k_usrregs_info,
 243     &m68k_regsets_info
 244   };
 245
 246 const regs_info *
 247 m68k_target::get_regs_info ()
 248 {
 249   return &myregs_info;
 250 }
 251
 252 void
 253 m68k_target::low_arch_setup ()
 254 {
 255   current_process ()->tdesc = tdesc_m68k;
 256 }
 257
 258 /* The linux target ops object.  */
 259
 260 linux_process_target *the_linux_target = &the_m68k_target;
 261
 262 void
 263 initialize_low_arch (void)
 264 {
 265   /* Initialize the Linux target descriptions.  */
 266   init_registers_m68k ();
 267
 268   initialize_regsets_info (&m68k_regsets_info);
 269 }