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68f5f838 SL |
1 | /* GNU/Linux/Nios II specific low level interface, for the remote server for |
2 | GDB. | |
b811d2c2 | 3 | Copyright (C) 2008-2020 Free Software Foundation, Inc. |
68f5f838 SL |
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" | |
21e94bd9 | 24 | #include "elf/common.h" |
5826e159 | 25 | #include "nat/gdb_ptrace.h" |
68f5f838 SL |
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 | ||
ef0478f6 TBA |
34 | /* Linux target op definitions for the NIOS II architecture. */ |
35 | ||
36 | class nios2_target : public linux_process_target | |
37 | { | |
38 | public: | |
39 | ||
797bcff5 TBA |
40 | protected: |
41 | ||
42 | void low_arch_setup () override; | |
ef0478f6 TBA |
43 | }; |
44 | ||
45 | /* The singleton target ops object. */ | |
46 | ||
47 | static nios2_target the_nios2_target; | |
48 | ||
68f5f838 SL |
49 | /* The following definition must agree with the number of registers |
50 | defined in "struct user_regs" in GLIBC | |
21e94bd9 | 51 | (sysdeps/unix/sysv/linux/nios2/sys/user.h), and also with |
68f5f838 SL |
52 | NIOS2_NUM_REGS in GDB proper. */ |
53 | ||
54 | #define nios2_num_regs 49 | |
55 | ||
56 | /* Defined in auto-generated file nios2-linux.c. */ | |
57 | ||
58 | void init_registers_nios2_linux (void); | |
3aee8918 | 59 | extern const struct target_desc *tdesc_nios2_linux; |
68f5f838 SL |
60 | |
61 | /* This union is used to convert between int and byte buffer | |
62 | representations of register contents. */ | |
63 | ||
64 | union nios2_register | |
65 | { | |
66 | unsigned char buf[4]; | |
67 | int reg32; | |
68 | }; | |
69 | ||
70 | /* Return the ptrace ``address'' of register REGNO. */ | |
71 | ||
72 | static int nios2_regmap[] = { | |
73 | -1, 1, 2, 3, 4, 5, 6, 7, | |
74 | 8, 9, 10, 11, 12, 13, 14, 15, | |
75 | 16, 17, 18, 19, 20, 21, 22, 23, | |
76 | 24, 25, 26, 27, 28, 29, 30, 31, | |
77 | 32, 33, 34, 35, 36, 37, 38, 39, | |
78 | 40, 41, 42, 43, 44, 45, 46, 47, | |
79 | 48, | |
80 | 0 | |
81 | }; | |
82 | ||
797bcff5 | 83 | /* Implement the low_arch_setup linux target ops method. */ |
68f5f838 | 84 | |
797bcff5 TBA |
85 | void |
86 | nios2_target::low_arch_setup () | |
68f5f838 | 87 | { |
3aee8918 | 88 | current_process ()->tdesc = tdesc_nios2_linux; |
68f5f838 SL |
89 | } |
90 | ||
91 | /* Implement the cannot_fetch_register linux_target_ops method. */ | |
92 | ||
93 | static int | |
94 | nios2_cannot_fetch_register (int regno) | |
95 | { | |
96 | if (nios2_regmap[regno] == -1) | |
97 | return 1; | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
102 | /* Implement the cannot_store_register linux_target_ops method. */ | |
103 | ||
104 | static int | |
105 | nios2_cannot_store_register (int regno) | |
106 | { | |
107 | if (nios2_regmap[regno] == -1) | |
108 | return 1; | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
af60a1ef SL |
113 | /* Breakpoint support. Also see comments on nios2_breakpoint_from_pc |
114 | in nios2-tdep.c. */ | |
115 | ||
116 | #if defined(__nios2_arch__) && __nios2_arch__ == 2 | |
117 | #define NIOS2_BREAKPOINT 0xb7fd0020 | |
118 | #define CDX_BREAKPOINT 0xd7c9 | |
119 | #else | |
120 | #define NIOS2_BREAKPOINT 0x003b6ffa | |
121 | #endif | |
68f5f838 | 122 | |
dd373349 AT |
123 | /* We only register the 4-byte breakpoint, even on R2 targets which also |
124 | support 2-byte breakpoints. Since there is no supports_z_point_type | |
125 | function provided, gdbserver never inserts software breakpoints itself | |
126 | and instead relies on GDB to insert the breakpoint of the correct length | |
127 | via a memory write. */ | |
af60a1ef | 128 | static const unsigned int nios2_breakpoint = NIOS2_BREAKPOINT; |
68f5f838 SL |
129 | #define nios2_breakpoint_len 4 |
130 | ||
dd373349 AT |
131 | /* Implementation of linux_target_ops method "sw_breakpoint_from_kind". */ |
132 | ||
133 | static const gdb_byte * | |
134 | nios2_sw_breakpoint_from_kind (int kind, int *size) | |
135 | { | |
136 | *size = nios2_breakpoint_len; | |
137 | return (const gdb_byte *) &nios2_breakpoint; | |
138 | } | |
139 | ||
68f5f838 SL |
140 | /* Implement the breakpoint_at linux_target_ops method. */ |
141 | ||
142 | static int | |
143 | nios2_breakpoint_at (CORE_ADDR where) | |
144 | { | |
145 | unsigned int insn; | |
146 | ||
af60a1ef SL |
147 | /* For R2, first check for the 2-byte CDX trap.n breakpoint encoding. */ |
148 | #if defined(__nios2_arch__) && __nios2_arch__ == 2 | |
52405d85 | 149 | the_target->read_memory (where, (unsigned char *) &insn, 2); |
af60a1ef SL |
150 | if (insn == CDX_BREAKPOINT) |
151 | return 1; | |
152 | #endif | |
153 | ||
52405d85 | 154 | the_target->read_memory (where, (unsigned char *) &insn, 4); |
68f5f838 SL |
155 | if (insn == nios2_breakpoint) |
156 | return 1; | |
157 | return 0; | |
158 | } | |
159 | ||
160 | /* Fetch the thread-local storage pointer for libthread_db. */ | |
161 | ||
162 | ps_err_e | |
754653a7 | 163 | ps_get_thread_area (struct ps_prochandle *ph, |
68f5f838 SL |
164 | lwpid_t lwpid, int idx, void **base) |
165 | { | |
166 | if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0) | |
167 | return PS_ERR; | |
168 | ||
169 | /* IDX is the bias from the thread pointer to the beginning of the | |
170 | thread descriptor. It has to be subtracted due to implementation | |
171 | quirks in libthread_db. */ | |
172 | *base = (void *) ((char *) *base - idx); | |
173 | ||
174 | return PS_OK; | |
175 | } | |
176 | ||
68f5f838 SL |
177 | /* Helper functions to collect/supply a single register REGNO. */ |
178 | ||
179 | static void | |
180 | nios2_collect_register (struct regcache *regcache, int regno, | |
181 | union nios2_register *reg) | |
182 | { | |
183 | union nios2_register tmp_reg; | |
184 | ||
185 | collect_register (regcache, regno, &tmp_reg.reg32); | |
186 | reg->reg32 = tmp_reg.reg32; | |
187 | } | |
188 | ||
189 | static void | |
190 | nios2_supply_register (struct regcache *regcache, int regno, | |
191 | const union nios2_register *reg) | |
192 | { | |
193 | supply_register (regcache, regno, reg->buf); | |
194 | } | |
195 | ||
196 | /* We have only a single register set on Nios II. */ | |
197 | ||
198 | static void | |
199 | nios2_fill_gregset (struct regcache *regcache, void *buf) | |
200 | { | |
b1c51e36 | 201 | union nios2_register *regset = (union nios2_register *) buf; |
68f5f838 SL |
202 | int i; |
203 | ||
204 | for (i = 1; i < nios2_num_regs; i++) | |
205 | nios2_collect_register (regcache, i, regset + i); | |
206 | } | |
207 | ||
208 | static void | |
209 | nios2_store_gregset (struct regcache *regcache, const void *buf) | |
210 | { | |
b1c51e36 | 211 | const union nios2_register *regset = (union nios2_register *) buf; |
68f5f838 SL |
212 | int i; |
213 | ||
214 | for (i = 0; i < nios2_num_regs; i++) | |
215 | nios2_supply_register (regcache, i, regset + i); | |
216 | } | |
68f5f838 | 217 | |
3aee8918 | 218 | static struct regset_info nios2_regsets[] = |
68f5f838 | 219 | { |
21e94bd9 SL |
220 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS, |
221 | nios2_num_regs * 4, GENERAL_REGS, | |
68f5f838 | 222 | nios2_fill_gregset, nios2_store_gregset }, |
50bc912a | 223 | NULL_REGSET |
68f5f838 SL |
224 | }; |
225 | ||
3aee8918 PA |
226 | static struct regsets_info nios2_regsets_info = |
227 | { | |
228 | nios2_regsets, /* regsets */ | |
229 | 0, /* num_regsets */ | |
230 | NULL, /* disabled_regsets */ | |
231 | }; | |
232 | ||
233 | static struct usrregs_info nios2_usrregs_info = | |
234 | { | |
235 | nios2_num_regs, | |
236 | nios2_regmap, | |
237 | }; | |
238 | ||
239 | static struct regs_info regs_info = | |
240 | { | |
241 | NULL, /* regset_bitmap */ | |
242 | &nios2_usrregs_info, | |
243 | &nios2_regsets_info | |
244 | }; | |
245 | ||
246 | static const struct regs_info * | |
247 | nios2_regs_info (void) | |
248 | { | |
249 | return ®s_info; | |
250 | } | |
251 | ||
68f5f838 SL |
252 | struct linux_target_ops the_low_target = |
253 | { | |
3aee8918 | 254 | nios2_regs_info, |
68f5f838 SL |
255 | nios2_cannot_fetch_register, |
256 | nios2_cannot_store_register, | |
257 | NULL, | |
276d4552 YQ |
258 | linux_get_pc_32bit, |
259 | linux_set_pc_32bit, | |
dd373349 AT |
260 | NULL, /* breakpoint_kind_from_pc */ |
261 | nios2_sw_breakpoint_from_kind, | |
fa5308bd | 262 | NULL, /* get_next_pcs */ |
68f5f838 SL |
263 | 0, |
264 | nios2_breakpoint_at, | |
265 | }; | |
3aee8918 | 266 | |
ef0478f6 TBA |
267 | /* The linux target ops object. */ |
268 | ||
269 | linux_process_target *the_linux_target = &the_nios2_target; | |
270 | ||
3aee8918 PA |
271 | void |
272 | initialize_low_arch (void) | |
273 | { | |
274 | init_registers_nios2_linux (); | |
275 | ||
276 | initialize_regsets_info (&nios2_regsets_info); | |
277 | } |