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