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 /* Defined in auto-generated file reg-m68k.c.  */
  23 void init_registers_m68k (void);
  24 extern const struct target_desc *tdesc_m68k;
  25
  26 #ifdef HAVE_SYS_REG_H
  27 #include <sys/reg.h>
  28 #endif
  29
  30 #define m68k_num_regs 29
  31 #define m68k_num_gregs 18
  32
  33 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  34 static int m68k_regmap[] =
  35 {
  36 #ifdef PT_D0
  37   PT_D0 * 4, PT_D1 * 4, PT_D2 * 4, PT_D3 * 4,
  38   PT_D4 * 4, PT_D5 * 4, PT_D6 * 4, PT_D7 * 4,
  39   PT_A0 * 4, PT_A1 * 4, PT_A2 * 4, PT_A3 * 4,
  40   PT_A4 * 4, PT_A5 * 4, PT_A6 * 4, PT_USP * 4,
  41   PT_SR * 4, PT_PC * 4,
  42 #else
  43   14 * 4, 0 * 4, 1 * 4, 2 * 4, 3 * 4, 4 * 4, 5 * 4, 6 * 4,
  44   7 * 4, 8 * 4, 9 * 4, 10 * 4, 11 * 4, 12 * 4, 13 * 4, 15 * 4,
  45   17 * 4, 18 * 4,
  46 #endif
  47 #ifdef PT_FP0
  48   PT_FP0 * 4, PT_FP1 * 4, PT_FP2 * 4, PT_FP3 * 4,
  49   PT_FP4 * 4, PT_FP5 * 4, PT_FP6 * 4, PT_FP7 * 4,
  50   PT_FPCR * 4, PT_FPSR * 4, PT_FPIAR * 4
  51 #else
  52   21 * 4, 24 * 4, 27 * 4, 30 * 4, 33 * 4, 36 * 4,
  53   39 * 4, 42 * 4, 45 * 4, 46 * 4, 47 * 4
  54 #endif
  55 };
  56
  57 static int
  58 m68k_cannot_store_register (int regno)
  59 {
  60   return (regno >= m68k_num_regs);
  61 }
  62
  63 static int
  64 m68k_cannot_fetch_register (int regno)
  65 {
  66   return (regno >= m68k_num_regs);
  67 }
  68
  69 #ifdef HAVE_PTRACE_GETREGS
  70 #include <sys/procfs.h>
  71 #include "nat/gdb_ptrace.h"
  72
  73 static void
  74 m68k_fill_gregset (struct regcache *regcache, void *buf)
  75 {
  76   int i;
  77
  78   for (i = 0; i < m68k_num_gregs; i++)
  79     collect_register (regcache, i, (char *) buf + m68k_regmap[i]);
  80 }
  81
  82 static void
  83 m68k_store_gregset (struct regcache *regcache, const void *buf)
  84 {
  85   int i;
  86
  87   for (i = 0; i < m68k_num_gregs; i++)
  88     supply_register (regcache, i, (const char *) buf + m68k_regmap[i]);
  89 }
  90
  91 static void
  92 m68k_fill_fpregset (struct regcache *regcache, void *buf)
  93 {
  94   int i;
  95
  96   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
  97     collect_register (regcache, i, ((char *) buf
  98                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
  99 }
 100
 101 static void
 102 m68k_store_fpregset (struct regcache *regcache, const void *buf)
 103 {
 104   int i;
 105
 106   for (i = m68k_num_gregs; i < m68k_num_regs; i++)
 107     supply_register (regcache, i, ((const char *) buf
 108                          + (m68k_regmap[i] - m68k_regmap[m68k_num_gregs])));
 109 }
 110
 111 #endif /* HAVE_PTRACE_GETREGS */
 112
 113 static struct regset_info m68k_regsets[] = {
 114 #ifdef HAVE_PTRACE_GETREGS
 115   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 116     GENERAL_REGS,
 117     m68k_fill_gregset, m68k_store_gregset },
 118   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 119     FP_REGS,
 120     m68k_fill_fpregset, m68k_store_fpregset },
 121 #endif /* HAVE_PTRACE_GETREGS */
 122   NULL_REGSET
 123 };
 124
 125 static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 126 #define m68k_breakpoint_len 2
 127
 128 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 129
 130 static const gdb_byte *
 131 m68k_sw_breakpoint_from_kind (int kind, int *size)
 132 {
 133   *size = m68k_breakpoint_len;
 134   return m68k_breakpoint;
 135 }
 136
 137 static int
 138 m68k_breakpoint_at (CORE_ADDR pc)
 139 {
 140   unsigned char c[2];
 141
 142   read_inferior_memory (pc, c, 2);
 143   if (c[0] == 0x4E && c[1] == 0x4F)
 144     return 1;
 145
 146   return 0;
 147 }
 148
 149 #include <asm/ptrace.h>
 150
 151 #ifdef PTRACE_GET_THREAD_AREA
 152 /* Fetch the thread-local storage pointer for libthread_db.  */
 153
 154 ps_err_e
 155 ps_get_thread_area (struct ps_prochandle *ph,
 156                     lwpid_t lwpid, int idx, void **base)
 157 {
 158   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 159     return PS_ERR;
 160
 161   /* IDX is the bias from the thread pointer to the beginning of the
 162      thread descriptor.  It has to be subtracted due to implementation
 163      quirks in libthread_db.  */
 164   *base = (void *) ((char *)*base - idx);
 165
 166   return PS_OK;
 167 }
 168 #endif /* PTRACE_GET_THREAD_AREA */
 169
 170 static struct regsets_info m68k_regsets_info =
 171   {
 172     m68k_regsets, /* regsets */
 173     0, /* num_regsets */
 174     NULL, /* disabled_regsets */
 175   };
 176
 177 static struct usrregs_info m68k_usrregs_info =
 178   {
 179     m68k_num_regs,
 180     m68k_regmap,
 181   };
 182
 183 static struct regs_info regs_info =
 184   {
 185     NULL, /* regset_bitmap */
 186     &m68k_usrregs_info,
 187     &m68k_regsets_info
 188   };
 189
 190 static const struct regs_info *
 191 m68k_regs_info (void)
 192 {
 193   return &regs_info;
 194 }
 195
 196 static void
 197 m68k_arch_setup (void)
 198 {
 199   current_process ()->tdesc = tdesc_m68k;
 200 }
 201
 202 /* Support for hardware single step.  */
 203
 204 static int
 205 m68k_supports_hardware_single_step (void)
 206 {
 207   return 1;
 208 }
 209
 210 struct linux_target_ops the_low_target = {
 211   m68k_arch_setup,
 212   m68k_regs_info,
 213   m68k_cannot_fetch_register,
 214   m68k_cannot_store_register,
 215   NULL, /* fetch_register */
 216   linux_get_pc_32bit,
 217   linux_set_pc_32bit,
 218   NULL, /* breakpoint_kind_from_pc */
 219   m68k_sw_breakpoint_from_kind,
 220   NULL,
 221   2,
 222   m68k_breakpoint_at,
 223   NULL, /* supports_z_point_type */
 224   NULL, /* insert_point */
 225   NULL, /* remove_point */
 226   NULL, /* stopped_by_watchpoint */
 227   NULL, /* stopped_data_address */
 228   NULL, /* collect_ptrace_register */
 229   NULL, /* supply_ptrace_register */
 230   NULL, /* siginfo_fixup */
 231   NULL, /* new_process */
 232   NULL, /* delete_process */
 233   NULL, /* new_thread */
 234   NULL, /* delete_thread */
 235   NULL, /* new_fork */
 236   NULL, /* prepare_to_resume */
 237   NULL, /* process_qsupported */
 238   NULL, /* supports_tracepoints */
 239   NULL, /* get_thread_area */
 240   NULL, /* install_fast_tracepoint_jump_pad */
 241   NULL, /* emit_ops */
 242   NULL, /* get_min_fast_tracepoint_insn_len */
 243   NULL, /* supports_range_stepping */
 244   NULL, /* breakpoint_kind_from_current_state */
 245   m68k_supports_hardware_single_step,
 246 };
 247
 248 void
 249 initialize_low_arch (void)
 250 {
 251   /* Initialize the Linux target descriptions.  */
 252   init_registers_m68k ();
 253
 254   initialize_regsets_info (&m68k_regsets_info);
 255 }