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68f5f838 SL |
1 | /* GNU/Linux/Nios II specific low level interface, for the remote server for |
2 | GDB. | |
32d0add0 | 3 | Copyright (C) 2008-2015 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 | ||
34 | /* The following definition must agree with the number of registers | |
35 | defined in "struct user_regs" in GLIBC | |
21e94bd9 | 36 | (sysdeps/unix/sysv/linux/nios2/sys/user.h), and also with |
68f5f838 SL |
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); | |
3aee8918 | 44 | extern const struct target_desc *tdesc_nios2_linux; |
68f5f838 SL |
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 | { | |
3aee8918 | 73 | current_process ()->tdesc = tdesc_nios2_linux; |
68f5f838 SL |
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 | /* Implement the get_pc linux_target_ops method. */ | |
99 | ||
100 | static CORE_ADDR | |
101 | nios2_get_pc (struct regcache *regcache) | |
102 | { | |
103 | union nios2_register pc; | |
104 | ||
105 | collect_register_by_name (regcache, "pc", pc.buf); | |
106 | return pc.reg32; | |
107 | } | |
108 | ||
109 | /* Implement the set_pc linux_target_ops method. */ | |
110 | ||
111 | static void | |
112 | nios2_set_pc (struct regcache *regcache, CORE_ADDR pc) | |
113 | { | |
114 | union nios2_register newpc; | |
115 | ||
116 | newpc.reg32 = pc; | |
117 | supply_register_by_name (regcache, "pc", newpc.buf); | |
118 | } | |
119 | ||
af60a1ef SL |
120 | /* Breakpoint support. Also see comments on nios2_breakpoint_from_pc |
121 | in nios2-tdep.c. */ | |
122 | ||
123 | #if defined(__nios2_arch__) && __nios2_arch__ == 2 | |
124 | #define NIOS2_BREAKPOINT 0xb7fd0020 | |
125 | #define CDX_BREAKPOINT 0xd7c9 | |
126 | #else | |
127 | #define NIOS2_BREAKPOINT 0x003b6ffa | |
128 | #endif | |
68f5f838 | 129 | |
af60a1ef | 130 | static const unsigned int nios2_breakpoint = NIOS2_BREAKPOINT; |
68f5f838 SL |
131 | #define nios2_breakpoint_len 4 |
132 | ||
133 | /* Implement the breakpoint_reinsert_addr linux_target_ops method. */ | |
134 | ||
135 | static CORE_ADDR | |
136 | nios2_reinsert_addr (void) | |
137 | { | |
138 | union nios2_register ra; | |
0bfdf32f | 139 | struct regcache *regcache = get_thread_regcache (current_thread, 1); |
68f5f838 SL |
140 | |
141 | collect_register_by_name (regcache, "ra", ra.buf); | |
142 | return ra.reg32; | |
143 | } | |
144 | ||
145 | /* Implement the breakpoint_at linux_target_ops method. */ | |
146 | ||
147 | static int | |
148 | nios2_breakpoint_at (CORE_ADDR where) | |
149 | { | |
150 | unsigned int insn; | |
151 | ||
af60a1ef SL |
152 | /* For R2, first check for the 2-byte CDX trap.n breakpoint encoding. */ |
153 | #if defined(__nios2_arch__) && __nios2_arch__ == 2 | |
154 | (*the_target->read_memory) (where, (unsigned char *) &insn, 2); | |
155 | if (insn == CDX_BREAKPOINT) | |
156 | return 1; | |
157 | #endif | |
158 | ||
68f5f838 SL |
159 | (*the_target->read_memory) (where, (unsigned char *) &insn, 4); |
160 | if (insn == nios2_breakpoint) | |
161 | return 1; | |
162 | return 0; | |
163 | } | |
164 | ||
165 | /* Fetch the thread-local storage pointer for libthread_db. */ | |
166 | ||
167 | ps_err_e | |
168 | ps_get_thread_area (const struct ps_prochandle *ph, | |
169 | lwpid_t lwpid, int idx, void **base) | |
170 | { | |
171 | if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0) | |
172 | return PS_ERR; | |
173 | ||
174 | /* IDX is the bias from the thread pointer to the beginning of the | |
175 | thread descriptor. It has to be subtracted due to implementation | |
176 | quirks in libthread_db. */ | |
177 | *base = (void *) ((char *) *base - idx); | |
178 | ||
179 | return PS_OK; | |
180 | } | |
181 | ||
68f5f838 SL |
182 | /* Helper functions to collect/supply a single register REGNO. */ |
183 | ||
184 | static void | |
185 | nios2_collect_register (struct regcache *regcache, int regno, | |
186 | union nios2_register *reg) | |
187 | { | |
188 | union nios2_register tmp_reg; | |
189 | ||
190 | collect_register (regcache, regno, &tmp_reg.reg32); | |
191 | reg->reg32 = tmp_reg.reg32; | |
192 | } | |
193 | ||
194 | static void | |
195 | nios2_supply_register (struct regcache *regcache, int regno, | |
196 | const union nios2_register *reg) | |
197 | { | |
198 | supply_register (regcache, regno, reg->buf); | |
199 | } | |
200 | ||
201 | /* We have only a single register set on Nios II. */ | |
202 | ||
203 | static void | |
204 | nios2_fill_gregset (struct regcache *regcache, void *buf) | |
205 | { | |
206 | union nios2_register *regset = buf; | |
207 | int i; | |
208 | ||
209 | for (i = 1; i < nios2_num_regs; i++) | |
210 | nios2_collect_register (regcache, i, regset + i); | |
211 | } | |
212 | ||
213 | static void | |
214 | nios2_store_gregset (struct regcache *regcache, const void *buf) | |
215 | { | |
216 | const union nios2_register *regset = buf; | |
217 | int i; | |
218 | ||
219 | for (i = 0; i < nios2_num_regs; i++) | |
220 | nios2_supply_register (regcache, i, regset + i); | |
221 | } | |
68f5f838 | 222 | |
3aee8918 | 223 | static struct regset_info nios2_regsets[] = |
68f5f838 | 224 | { |
21e94bd9 SL |
225 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS, |
226 | nios2_num_regs * 4, GENERAL_REGS, | |
68f5f838 | 227 | nios2_fill_gregset, nios2_store_gregset }, |
68f5f838 SL |
228 | { 0, 0, 0, -1, -1, NULL, NULL } |
229 | }; | |
230 | ||
3aee8918 PA |
231 | static struct regsets_info nios2_regsets_info = |
232 | { | |
233 | nios2_regsets, /* regsets */ | |
234 | 0, /* num_regsets */ | |
235 | NULL, /* disabled_regsets */ | |
236 | }; | |
237 | ||
238 | static struct usrregs_info nios2_usrregs_info = | |
239 | { | |
240 | nios2_num_regs, | |
241 | nios2_regmap, | |
242 | }; | |
243 | ||
244 | static struct regs_info regs_info = | |
245 | { | |
246 | NULL, /* regset_bitmap */ | |
247 | &nios2_usrregs_info, | |
248 | &nios2_regsets_info | |
249 | }; | |
250 | ||
251 | static const struct regs_info * | |
252 | nios2_regs_info (void) | |
253 | { | |
254 | return ®s_info; | |
255 | } | |
256 | ||
68f5f838 SL |
257 | struct linux_target_ops the_low_target = |
258 | { | |
259 | nios2_arch_setup, | |
3aee8918 | 260 | nios2_regs_info, |
68f5f838 SL |
261 | nios2_cannot_fetch_register, |
262 | nios2_cannot_store_register, | |
263 | NULL, | |
264 | nios2_get_pc, | |
265 | nios2_set_pc, | |
af60a1ef SL |
266 | |
267 | /* We only register the 4-byte breakpoint, even on R2 targets which also | |
268 | support 2-byte breakpoints. Since there is no supports_z_point_type | |
269 | function provided, gdbserver never inserts software breakpoints itself | |
270 | and instead relies on GDB to insert the breakpoint of the correct length | |
271 | via a memory write. */ | |
68f5f838 SL |
272 | (const unsigned char *) &nios2_breakpoint, |
273 | nios2_breakpoint_len, | |
274 | nios2_reinsert_addr, | |
275 | 0, | |
276 | nios2_breakpoint_at, | |
277 | }; | |
3aee8918 PA |
278 | |
279 | void | |
280 | initialize_low_arch (void) | |
281 | { | |
282 | init_registers_nios2_linux (); | |
283 | ||
284 | initialize_regsets_info (&nios2_regsets_info); | |
285 | } |