1/* GNU/Linux/m68k specific low level interface, for the remote server for GDB.
2   Copyright (C) 1995-2023 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
24class m68k_target : public linux_process_target
25{
26public:
27
28  const regs_info *get_regs_info () override;
29
30  const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
31
32protected:
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
53static m68k_target the_m68k_target;
54
55bool
56m68k_target::low_supports_breakpoints ()
57{
58  return true;
59}
60
61CORE_ADDR
62m68k_target::low_get_pc (regcache *regcache)
63{
64  return linux_get_pc_32bit (regcache);
65}
66
67void
68m68k_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
69{
70  linux_set_pc_32bit (regcache, pc);
71}
72
73int
74m68k_target::low_decr_pc_after_break ()
75{
76  return 2;
77}
78
79/* Defined in auto-generated file reg-m68k.c.  */
80void init_registers_m68k (void);
81extern 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 */
91static 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
114bool
115m68k_target::low_cannot_store_register (int regno)
116{
117  return (regno >= m68k_num_regs);
118}
119
120bool
121m68k_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
130static void
131m68k_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
139static void
140m68k_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
148static void
149m68k_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
158static void
159m68k_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
170static 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
182static 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
187const gdb_byte *
188m68k_target::sw_breakpoint_from_kind (int kind, int *size)
189{
190  *size = m68k_breakpoint_len;
191  return m68k_breakpoint;
192}
193
194bool
195m68k_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
211ps_err_e
212ps_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
227static struct regsets_info m68k_regsets_info =
228  {
229    m68k_regsets, /* regsets */
230    0, /* num_regsets */
231    NULL, /* disabled_regsets */
232  };
233
234static struct usrregs_info m68k_usrregs_info =
235  {
236    m68k_num_regs,
237    m68k_regmap,
238  };
239
240static struct regs_info myregs_info =
241  {
242    NULL, /* regset_bitmap */
243    &m68k_usrregs_info,
244    &m68k_regsets_info
245  };
246
247const regs_info *
248m68k_target::get_regs_info ()
249{
250  return &myregs_info;
251}
252
253void
254m68k_target::low_arch_setup ()
255{
256  current_process ()->tdesc = tdesc_m68k;
257}
258
259/* The linux target ops object.  */
260
261linux_process_target *the_linux_target = &the_m68k_target;
262
263void
264initialize_low_arch (void)
265{
266  /* Initialize the Linux target descriptions.  */
267  init_registers_m68k ();
268
269  initialize_regsets_info (&m68k_regsets_info);
270}
271