1/* GNU/Linux/MIPS specific low level interface, for the remote server for GDB.
2   Copyright 1995, 1996, 1998, 1999, 2000, 2001, 2002
3   Free Software Foundation, Inc.
4
5   This file is part of GDB.
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 2 of the License, or
10   (at your option) any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program; if not, write to the Free Software
19   Foundation, Inc., 59 Temple Place - Suite 330,
20   Boston, MA 02111-1307, USA.  */
21
22#include "server.h"
23#include "linux-low.h"
24
25#ifdef HAVE_SYS_REG_H
26#include <sys/reg.h>
27#endif
28
29#define mips_num_regs 90
30
31#include <asm/ptrace.h>
32
33/* Return the ptrace ``address'' of register REGNO. */
34
35/* Matches mips_generic32_regs */
36static int mips_regmap[] = {
37  0,  1,  2,  3,  4,  5,  6,  7,
38  8,  9,  10, 11, 12, 13, 14, 15,
39  16, 17, 18, 19, 20, 21, 22, 23,
40  24, 25, 26, 27, 28, 29, 30, 31,
41
42  -1, MMLO, MMHI, BADVADDR, CAUSE, PC,
43
44  FPR_BASE,      FPR_BASE + 1,  FPR_BASE + 2,  FPR_BASE + 3,
45  FPR_BASE + 4,  FPR_BASE + 5,  FPR_BASE + 6,  FPR_BASE + 7,
46  FPR_BASE + 8,  FPR_BASE + 8,  FPR_BASE + 10, FPR_BASE + 11,
47  FPR_BASE + 12, FPR_BASE + 13, FPR_BASE + 14, FPR_BASE + 15,
48  FPR_BASE + 16, FPR_BASE + 17, FPR_BASE + 18, FPR_BASE + 19,
49  FPR_BASE + 20, FPR_BASE + 21, FPR_BASE + 22, FPR_BASE + 23,
50  FPR_BASE + 24, FPR_BASE + 25, FPR_BASE + 26, FPR_BASE + 27,
51  FPR_BASE + 28, FPR_BASE + 29, FPR_BASE + 30, FPR_BASE + 31,
52  FPC_CSR, FPC_EIR,
53
54  -1, -1,
55  -1, -1, -1, -1, -1, -1, -1, -1,
56  -1, -1, -1, -1, -1, -1, -1, -1,
57};
58
59/* From mips-linux-nat.c.  */
60
61/* Pseudo registers can not be read.  ptrace does not provide a way to
62   read (or set) PS_REGNUM, and there's no point in reading or setting
63   ZERO_REGNUM.  We also can not set BADVADDR, CAUSE, or FCRIR via
64   ptrace().  */
65
66static int
67mips_cannot_fetch_register (int regno)
68{
69  if (mips_regmap[regno] == -1)
70    return 1;
71
72  if (find_regno ("zero") == regno)
73    return 1;
74
75  return 0;
76}
77
78static int
79mips_cannot_store_register (int regno)
80{
81  if (mips_regmap[regno] == -1)
82    return 1;
83
84  if (find_regno ("zero") == regno)
85    return 1;
86
87  if (find_regno ("cause") == regno)
88    return 1;
89
90  if (find_regno ("bad") == regno)
91    return 1;
92
93  if (find_regno ("fir") == regno)
94    return 1;
95
96  return 0;
97}
98
99static CORE_ADDR
100mips_get_pc ()
101{
102  unsigned long pc;
103  collect_register_by_name ("pc", &pc);
104  return pc;
105}
106
107static void
108mips_set_pc (CORE_ADDR pc)
109{
110  unsigned long newpc = pc;
111  supply_register_by_name ("pc", &newpc);
112}
113
114/* Correct in either endianness.  */
115static const unsigned long mips_breakpoint = 0x0005000d;
116#define mips_breakpoint_len 4
117
118/* We only place breakpoints in empty marker functions, and thread locking
119   is outside of the function.  So rather than importing software single-step,
120   we can just run until exit.  */
121static CORE_ADDR
122mips_reinsert_addr ()
123{
124  unsigned long pc;
125  collect_register_by_name ("ra", &pc);
126  return pc;
127}
128
129static int
130mips_breakpoint_at (CORE_ADDR where)
131{
132  unsigned long insn;
133
134  (*the_target->read_memory) (where, (char *) &insn, 4);
135  if (insn == mips_breakpoint)
136    return 1;
137
138  /* If necessary, recognize more trap instructions here.  GDB only uses the
139     one.  */
140  return 0;
141}
142
143struct linux_target_ops the_low_target = {
144  mips_num_regs,
145  mips_regmap,
146  mips_cannot_fetch_register,
147  mips_cannot_store_register,
148  mips_get_pc,
149  mips_set_pc,
150  (const char *) &mips_breakpoint,
151  mips_breakpoint_len,
152  mips_reinsert_addr,
153  0,
154  mips_breakpoint_at,
155};
156