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linux-nios2-low.c
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1 /* GNU/Linux/Nios II specific low level interface, for the remote server for
2 GDB.
3 Copyright (C) 2008-2018 Free Software Foundation, Inc.
4
5 Contributed by Mentor Graphics, Inc.
6
7 This file is part of GDB.
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21
22 #include "server.h"
23 #include "linux-low.h"
24 #include "elf/common.h"
25 #include "nat/gdb_ptrace.h"
26 #include <endian.h>
27 #include "gdb_proc_service.h"
28 #include <asm/ptrace.h>
29
30 #ifndef PTRACE_GET_THREAD_AREA
31 #define PTRACE_GET_THREAD_AREA 25
32 #endif
33
34 /* The following definition must agree with the number of registers
35 defined in "struct user_regs" in GLIBC
36 (sysdeps/unix/sysv/linux/nios2/sys/user.h), and also with
37 NIOS2_NUM_REGS in GDB proper. */
38
39 #define nios2_num_regs 49
40
41 /* Defined in auto-generated file nios2-linux.c. */
42
43 void init_registers_nios2_linux (void);
44 extern const struct target_desc *tdesc_nios2_linux;
45
46 /* This union is used to convert between int and byte buffer
47 representations of register contents. */
48
49 union nios2_register
50 {
51 unsigned char buf[4];
52 int reg32;
53 };
54
55 /* Return the ptrace ``address'' of register REGNO. */
56
57 static int nios2_regmap[] = {
58 -1, 1, 2, 3, 4, 5, 6, 7,
59 8, 9, 10, 11, 12, 13, 14, 15,
60 16, 17, 18, 19, 20, 21, 22, 23,
61 24, 25, 26, 27, 28, 29, 30, 31,
62 32, 33, 34, 35, 36, 37, 38, 39,
63 40, 41, 42, 43, 44, 45, 46, 47,
64 48,
65 0
66 };
67
68 /* Implement the arch_setup linux_target_ops method. */
69
70 static void
71 nios2_arch_setup (void)
72 {
73 current_process ()->tdesc = tdesc_nios2_linux;
74 }
75
76 /* Implement the cannot_fetch_register linux_target_ops method. */
77
78 static int
79 nios2_cannot_fetch_register (int regno)
80 {
81 if (nios2_regmap[regno] == -1)
82 return 1;
83
84 return 0;
85 }
86
87 /* Implement the cannot_store_register linux_target_ops method. */
88
89 static int
90 nios2_cannot_store_register (int regno)
91 {
92 if (nios2_regmap[regno] == -1)
93 return 1;
94
95 return 0;
96 }
97
98 /* Breakpoint support. Also see comments on nios2_breakpoint_from_pc
99 in nios2-tdep.c. */
100
101 #if defined(__nios2_arch__) && __nios2_arch__ == 2
102 #define NIOS2_BREAKPOINT 0xb7fd0020
103 #define CDX_BREAKPOINT 0xd7c9
104 #else
105 #define NIOS2_BREAKPOINT 0x003b6ffa
106 #endif
107
108 /* We only register the 4-byte breakpoint, even on R2 targets which also
109 support 2-byte breakpoints. Since there is no supports_z_point_type
110 function provided, gdbserver never inserts software breakpoints itself
111 and instead relies on GDB to insert the breakpoint of the correct length
112 via a memory write. */
113 static const unsigned int nios2_breakpoint = NIOS2_BREAKPOINT;
114 #define nios2_breakpoint_len 4
115
116 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind". */
117
118 static const gdb_byte *
119 nios2_sw_breakpoint_from_kind (int kind, int *size)
120 {
121 *size = nios2_breakpoint_len;
122 return (const gdb_byte *) &nios2_breakpoint;
123 }
124
125 /* Implement the breakpoint_at linux_target_ops method. */
126
127 static int
128 nios2_breakpoint_at (CORE_ADDR where)
129 {
130 unsigned int insn;
131
132 /* For R2, first check for the 2-byte CDX trap.n breakpoint encoding. */
133 #if defined(__nios2_arch__) && __nios2_arch__ == 2
134 (*the_target->read_memory) (where, (unsigned char *) &insn, 2);
135 if (insn == CDX_BREAKPOINT)
136 return 1;
137 #endif
138
139 (*the_target->read_memory) (where, (unsigned char *) &insn, 4);
140 if (insn == nios2_breakpoint)
141 return 1;
142 return 0;
143 }
144
145 /* Fetch the thread-local storage pointer for libthread_db. */
146
147 ps_err_e
148 ps_get_thread_area (struct ps_prochandle *ph,
149 lwpid_t lwpid, int idx, void **base)
150 {
151 if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
152 return PS_ERR;
153
154 /* IDX is the bias from the thread pointer to the beginning of the
155 thread descriptor. It has to be subtracted due to implementation
156 quirks in libthread_db. */
157 *base = (void *) ((char *) *base - idx);
158
159 return PS_OK;
160 }
161
162 /* Helper functions to collect/supply a single register REGNO. */
163
164 static void
165 nios2_collect_register (struct regcache *regcache, int regno,
166 union nios2_register *reg)
167 {
168 union nios2_register tmp_reg;
169
170 collect_register (regcache, regno, &tmp_reg.reg32);
171 reg->reg32 = tmp_reg.reg32;
172 }
173
174 static void
175 nios2_supply_register (struct regcache *regcache, int regno,
176 const union nios2_register *reg)
177 {
178 supply_register (regcache, regno, reg->buf);
179 }
180
181 /* We have only a single register set on Nios II. */
182
183 static void
184 nios2_fill_gregset (struct regcache *regcache, void *buf)
185 {
186 union nios2_register *regset = (union nios2_register *) buf;
187 int i;
188
189 for (i = 1; i < nios2_num_regs; i++)
190 nios2_collect_register (regcache, i, regset + i);
191 }
192
193 static void
194 nios2_store_gregset (struct regcache *regcache, const void *buf)
195 {
196 const union nios2_register *regset = (union nios2_register *) buf;
197 int i;
198
199 for (i = 0; i < nios2_num_regs; i++)
200 nios2_supply_register (regcache, i, regset + i);
201 }
202
203 static struct regset_info nios2_regsets[] =
204 {
205 { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
206 nios2_num_regs * 4, GENERAL_REGS,
207 nios2_fill_gregset, nios2_store_gregset },
208 NULL_REGSET
209 };
210
211 static struct regsets_info nios2_regsets_info =
212 {
213 nios2_regsets, /* regsets */
214 0, /* num_regsets */
215 NULL, /* disabled_regsets */
216 };
217
218 static struct usrregs_info nios2_usrregs_info =
219 {
220 nios2_num_regs,
221 nios2_regmap,
222 };
223
224 static struct regs_info regs_info =
225 {
226 NULL, /* regset_bitmap */
227 &nios2_usrregs_info,
228 &nios2_regsets_info
229 };
230
231 static const struct regs_info *
232 nios2_regs_info (void)
233 {
234 return &regs_info;
235 }
236
237 struct linux_target_ops the_low_target =
238 {
239 nios2_arch_setup,
240 nios2_regs_info,
241 nios2_cannot_fetch_register,
242 nios2_cannot_store_register,
243 NULL,
244 linux_get_pc_32bit,
245 linux_set_pc_32bit,
246 NULL, /* breakpoint_kind_from_pc */
247 nios2_sw_breakpoint_from_kind,
248 NULL, /* get_next_pcs */
249 0,
250 nios2_breakpoint_at,
251 };
252
253 void
254 initialize_low_arch (void)
255 {
256 init_registers_nios2_linux ();
257
258 initialize_regsets_info (&nios2_regsets_info);
259 }
lwpid_t
unsigned int lwpid_t
Definition: gdb_proc_service.h:63
init_registers_nios2_linux
void init_registers_nios2_linux(void)
collect_register
void collect_register(struct regcache *regcache, int n, void *buf)
Definition: regcache.c:402
nios2_regsets
static struct regset_info nios2_regsets[]
Definition: linux-nios2-low.c:203
nios2_breakpoint_len
#define nios2_breakpoint_len
Definition: linux-nios2-low.c:114
CORE_ADDR
bfd_vma CORE_ADDR
Definition: common-types.h:41
nios2_num_regs
#define nios2_num_regs
Definition: linux-nios2-low.c:39
NIOS2_BREAKPOINT
#define NIOS2_BREAKPOINT
Definition: linux-nios2-low.c:105
nios2_breakpoint
static const unsigned int nios2_breakpoint
Definition: linux-nios2-low.c:113
initialize_low_arch
void initialize_low_arch(void)
Definition: linux-nios2-low.c:254
ps_prochandle
Definition: gdb_proc_service.h:150
ps_err_e
ps_err_e
Definition: gdb_proc_service.h:51
linux_target_ops
Definition: linux-low.h:128
the_target
struct target_ops * the_target
Definition: target.c:24
process_info::tdesc
const struct target_desc * tdesc
Definition: inferiors.h:67
regcache
Definition: regcache.h:31
gdb_proc_service.h
ptrace
PTRACE_TYPE_RET ptrace()
linux_get_pc_32bit
CORE_ADDR linux_get_pc_32bit(struct regcache *regcache)
Definition: linux-low.c:7411
linux-low.h
nios2_supply_register
static void nios2_supply_register(struct regcache *regcache, int regno, const union nios2_register *reg)
Definition: linux-nios2-low.c:175
the_low_target
struct linux_target_ops the_low_target
Definition: linux-nios2-low.c:237
nios2_register::buf
unsigned char buf[4]
Definition: linux-nios2-low.c:51
nios2_cannot_store_register
static int nios2_cannot_store_register(int regno)
Definition: linux-nios2-low.c:90
regs_info
Definition: linux-low.h:94
PTRACE_GET_THREAD_AREA
#define PTRACE_GET_THREAD_AREA
Definition: linux-nios2-low.c:31
server.h
nios2_sw_breakpoint_from_kind
static const gdb_byte * nios2_sw_breakpoint_from_kind(int kind, int *size)
Definition: linux-nios2-low.c:119
PTRACE_SETREGSET
#define PTRACE_SETREGSET
Definition: linux-ptrace.h:51
current_process
struct process_info * current_process(void)
Definition: inferiors.c:210
usrregs_info
Definition: linux-low.h:83
PS_ERR
Definition: gdb_proc_service.h:54
PTRACE_GETREGSET
#define PTRACE_GETREGSET
Definition: linux-ptrace.h:47
linux_set_pc_32bit
void linux_set_pc_32bit(struct regcache *regcache, CORE_ADDR pc)
Definition: linux-low.c:7400
nios2_collect_register
static void nios2_collect_register(struct regcache *regcache, int regno, union nios2_register *reg)
Definition: linux-nios2-low.c:165
nios2_regmap
static int nios2_regmap[]
Definition: linux-nios2-low.c:57
gdb_byte
bfd_byte gdb_byte
Definition: common-types.h:38
ps_get_thread_area
ps_err_e ps_get_thread_area(struct ps_prochandle *ph, lwpid_t lwpid, int idx, void **base)
Definition: linux-nios2-low.c:148
nios2_store_gregset
static void nios2_store_gregset(struct regcache *regcache, const void *buf)
Definition: linux-nios2-low.c:194
target_desc
Definition: tdesc.h:33
target_ops::read_memory
int(* read_memory)(CORE_ADDR memaddr, unsigned char *myaddr, int len)
Definition: target.h:166
nios2_breakpoint_at
static int nios2_breakpoint_at(CORE_ADDR where)
Definition: linux-nios2-low.c:128
nios2_usrregs_info
static struct usrregs_info nios2_usrregs_info
Definition: linux-nios2-low.c:218
tdesc_nios2_linux
const struct target_desc * tdesc_nios2_linux
PS_OK
Definition: gdb_proc_service.h:53
nios2_cannot_fetch_register
static int nios2_cannot_fetch_register(int regno)
Definition: linux-nios2-low.c:79
gdb_ptrace.h
nios2_arch_setup
static void nios2_arch_setup(void)
Definition: linux-nios2-low.c:71
nios2_regsets_info
static struct regsets_info nios2_regsets_info
Definition: linux-nios2-low.c:211
nios2_register
Definition: linux-nios2-low.c:49
supply_register
void supply_register(struct regcache *regcache, int n, const void *buf)
Definition: regcache.c:318
nios2_fill_gregset
static void nios2_fill_gregset(struct regcache *regcache, void *buf)
Definition: linux-nios2-low.c:184
regs_info
static struct regs_info regs_info
Definition: linux-nios2-low.c:224
nios2_regs_info
static const struct regs_info * nios2_regs_info(void)
Definition: linux-nios2-low.c:232
nios2_register::reg32
int reg32
Definition: linux-nios2-low.c:52