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bf84f706 MR |
1 | /* GNU/Linux/RISC-V specific low level interface, for the remote server |
2 | for GDB. | |
3 | Copyright (C) 2020 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 3 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, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include "server.h" | |
21 | ||
22 | #include "linux-low.h" | |
23 | #include "tdesc.h" | |
24 | #include "elf/common.h" | |
25 | #include "nat/riscv-linux-tdesc.h" | |
26 | #include "opcode/riscv.h" | |
27 | ||
28 | /* Work around glibc header breakage causing ELF_NFPREG not to be usable. */ | |
29 | #ifndef NFPREG | |
30 | # define NFPREG 33 | |
31 | #endif | |
32 | ||
ef0478f6 TBA |
33 | /* Linux target op definitions for the RISC-V architecture. */ |
34 | ||
35 | class riscv_target : public linux_process_target | |
36 | { | |
37 | public: | |
38 | ||
aa8d21c9 TBA |
39 | const regs_info *get_regs_info () override; |
40 | ||
06250e4e TBA |
41 | int breakpoint_kind_from_pc (CORE_ADDR *pcptr) override; |
42 | ||
797bcff5 TBA |
43 | protected: |
44 | ||
45 | void low_arch_setup () override; | |
daca57a7 TBA |
46 | |
47 | bool low_cannot_fetch_register (int regno) override; | |
48 | ||
49 | bool low_cannot_store_register (int regno) override; | |
bd70b1f2 TBA |
50 | |
51 | bool low_fetch_register (regcache *regcache, int regno) override; | |
bf9ae9d8 TBA |
52 | |
53 | bool low_supports_breakpoints () override; | |
54 | ||
55 | CORE_ADDR low_get_pc (regcache *regcache) override; | |
56 | ||
57 | void low_set_pc (regcache *regcache, CORE_ADDR newpc) override; | |
ef0478f6 TBA |
58 | }; |
59 | ||
60 | /* The singleton target ops object. */ | |
61 | ||
62 | static riscv_target the_riscv_target; | |
63 | ||
daca57a7 TBA |
64 | bool |
65 | riscv_target::low_cannot_fetch_register (int regno) | |
66 | { | |
67 | gdb_assert_not_reached ("linux target op low_cannot_fetch_register " | |
68 | "is not implemented by the target"); | |
69 | } | |
70 | ||
71 | bool | |
72 | riscv_target::low_cannot_store_register (int regno) | |
73 | { | |
74 | gdb_assert_not_reached ("linux target op low_cannot_store_register " | |
75 | "is not implemented by the target"); | |
76 | } | |
77 | ||
797bcff5 | 78 | /* Implementation of linux target ops method "low_arch_setup". */ |
bf84f706 | 79 | |
797bcff5 TBA |
80 | void |
81 | riscv_target::low_arch_setup () | |
bf84f706 MR |
82 | { |
83 | static const char *expedite_regs[] = { "sp", "pc", NULL }; | |
84 | ||
85 | const riscv_gdbarch_features features | |
86 | = riscv_linux_read_features (lwpid_of (current_thread)); | |
87 | target_desc *tdesc = riscv_create_target_description (features); | |
88 | ||
89 | if (!tdesc->expedite_regs) | |
90 | init_target_desc (tdesc, expedite_regs); | |
91 | current_process ()->tdesc = tdesc; | |
92 | } | |
93 | ||
94 | /* Collect GPRs from REGCACHE into BUF. */ | |
95 | ||
96 | static void | |
97 | riscv_fill_gregset (struct regcache *regcache, void *buf) | |
98 | { | |
99 | const struct target_desc *tdesc = regcache->tdesc; | |
100 | elf_gregset_t *regset = (elf_gregset_t *) buf; | |
101 | int regno = find_regno (tdesc, "zero"); | |
102 | int i; | |
103 | ||
104 | collect_register_by_name (regcache, "pc", *regset); | |
105 | for (i = 1; i < ARRAY_SIZE (*regset); i++) | |
106 | collect_register (regcache, regno + i, *regset + i); | |
107 | } | |
108 | ||
109 | /* Supply GPRs from BUF into REGCACHE. */ | |
110 | ||
111 | static void | |
112 | riscv_store_gregset (struct regcache *regcache, const void *buf) | |
113 | { | |
114 | const elf_gregset_t *regset = (const elf_gregset_t *) buf; | |
115 | const struct target_desc *tdesc = regcache->tdesc; | |
116 | int regno = find_regno (tdesc, "zero"); | |
117 | int i; | |
118 | ||
119 | supply_register_by_name (regcache, "pc", *regset); | |
120 | supply_register_zeroed (regcache, regno); | |
121 | for (i = 1; i < ARRAY_SIZE (*regset); i++) | |
122 | supply_register (regcache, regno + i, *regset + i); | |
123 | } | |
124 | ||
125 | /* Collect FPRs from REGCACHE into BUF. */ | |
126 | ||
127 | static void | |
128 | riscv_fill_fpregset (struct regcache *regcache, void *buf) | |
129 | { | |
130 | const struct target_desc *tdesc = regcache->tdesc; | |
131 | int regno = find_regno (tdesc, "ft0"); | |
132 | int flen = register_size (regcache->tdesc, regno); | |
133 | gdb_byte *regbuf = (gdb_byte *) buf; | |
134 | int i; | |
135 | ||
136 | for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen) | |
137 | collect_register (regcache, regno + i, regbuf); | |
138 | collect_register_by_name (regcache, "fcsr", regbuf); | |
139 | } | |
140 | ||
141 | /* Supply FPRs from BUF into REGCACHE. */ | |
142 | ||
143 | static void | |
144 | riscv_store_fpregset (struct regcache *regcache, const void *buf) | |
145 | { | |
146 | const struct target_desc *tdesc = regcache->tdesc; | |
147 | int regno = find_regno (tdesc, "ft0"); | |
148 | int flen = register_size (regcache->tdesc, regno); | |
149 | const gdb_byte *regbuf = (const gdb_byte *) buf; | |
150 | int i; | |
151 | ||
152 | for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen) | |
153 | supply_register (regcache, regno + i, regbuf); | |
154 | supply_register_by_name (regcache, "fcsr", regbuf); | |
155 | } | |
156 | ||
157 | /* RISC-V/Linux regsets. FPRs are optional and come in different sizes, | |
158 | so define multiple regsets for them marking them all as OPTIONAL_REGS | |
159 | rather than FP_REGS, so that "regsets_fetch_inferior_registers" picks | |
160 | the right one according to size. */ | |
161 | static struct regset_info riscv_regsets[] = { | |
162 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS, | |
163 | sizeof (elf_gregset_t), GENERAL_REGS, | |
164 | riscv_fill_gregset, riscv_store_gregset }, | |
165 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, | |
166 | sizeof (struct __riscv_mc_q_ext_state), OPTIONAL_REGS, | |
167 | riscv_fill_fpregset, riscv_store_fpregset }, | |
168 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, | |
169 | sizeof (struct __riscv_mc_d_ext_state), OPTIONAL_REGS, | |
170 | riscv_fill_fpregset, riscv_store_fpregset }, | |
171 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, | |
172 | sizeof (struct __riscv_mc_f_ext_state), OPTIONAL_REGS, | |
173 | riscv_fill_fpregset, riscv_store_fpregset }, | |
174 | NULL_REGSET | |
175 | }; | |
176 | ||
177 | /* RISC-V/Linux regset information. */ | |
178 | static struct regsets_info riscv_regsets_info = | |
179 | { | |
180 | riscv_regsets, /* regsets */ | |
181 | 0, /* num_regsets */ | |
182 | NULL, /* disabled_regsets */ | |
183 | }; | |
184 | ||
185 | /* Definition of linux_target_ops data member "regs_info". */ | |
186 | static struct regs_info riscv_regs = | |
187 | { | |
188 | NULL, /* regset_bitmap */ | |
189 | NULL, /* usrregs */ | |
190 | &riscv_regsets_info, | |
191 | }; | |
192 | ||
aa8d21c9 | 193 | /* Implementation of linux target ops method "get_regs_info". */ |
bf84f706 | 194 | |
aa8d21c9 TBA |
195 | const regs_info * |
196 | riscv_target::get_regs_info () | |
bf84f706 MR |
197 | { |
198 | return &riscv_regs; | |
199 | } | |
200 | ||
bd70b1f2 | 201 | /* Implementation of linux target ops method "low_fetch_register". */ |
bf84f706 | 202 | |
bd70b1f2 TBA |
203 | bool |
204 | riscv_target::low_fetch_register (regcache *regcache, int regno) | |
bf84f706 MR |
205 | { |
206 | const struct target_desc *tdesc = regcache->tdesc; | |
207 | ||
208 | if (regno != find_regno (tdesc, "zero")) | |
bd70b1f2 | 209 | return false; |
bf84f706 | 210 | supply_register_zeroed (regcache, regno); |
bd70b1f2 | 211 | return true; |
bf84f706 MR |
212 | } |
213 | ||
bf9ae9d8 TBA |
214 | bool |
215 | riscv_target::low_supports_breakpoints () | |
216 | { | |
217 | return true; | |
218 | } | |
219 | ||
220 | /* Implementation of linux target ops method "low_get_pc". */ | |
bf84f706 | 221 | |
bf9ae9d8 TBA |
222 | CORE_ADDR |
223 | riscv_target::low_get_pc (regcache *regcache) | |
bf84f706 MR |
224 | { |
225 | elf_gregset_t regset; | |
226 | ||
227 | if (sizeof (regset[0]) == 8) | |
228 | return linux_get_pc_64bit (regcache); | |
229 | else | |
230 | return linux_get_pc_32bit (regcache); | |
231 | } | |
232 | ||
bf9ae9d8 | 233 | /* Implementation of linux target ops method "low_set_pc". */ |
bf84f706 | 234 | |
bf9ae9d8 TBA |
235 | void |
236 | riscv_target::low_set_pc (regcache *regcache, CORE_ADDR newpc) | |
bf84f706 MR |
237 | { |
238 | elf_gregset_t regset; | |
239 | ||
240 | if (sizeof (regset[0]) == 8) | |
241 | linux_set_pc_64bit (regcache, newpc); | |
242 | else | |
243 | linux_set_pc_32bit (regcache, newpc); | |
244 | } | |
245 | ||
246 | /* Correct in either endianness. */ | |
247 | static const uint16_t riscv_ibreakpoint[] = { 0x0073, 0x0010 }; | |
248 | static const uint16_t riscv_cbreakpoint = 0x9002; | |
249 | ||
06250e4e | 250 | /* Implementation of target ops method "breakpoint_kind_from_pc". */ |
bf84f706 | 251 | |
06250e4e TBA |
252 | int |
253 | riscv_target::breakpoint_kind_from_pc (CORE_ADDR *pcptr) | |
bf84f706 MR |
254 | { |
255 | union | |
256 | { | |
257 | gdb_byte bytes[2]; | |
258 | uint16_t insn; | |
259 | } | |
260 | buf; | |
261 | ||
262 | if (target_read_memory (*pcptr, buf.bytes, sizeof (buf.insn)) == 0 | |
263 | && riscv_insn_length (buf.insn == sizeof (riscv_ibreakpoint))) | |
264 | return sizeof (riscv_ibreakpoint); | |
265 | else | |
266 | return sizeof (riscv_cbreakpoint); | |
267 | } | |
268 | ||
269 | /* Implementation of linux_target_ops method "sw_breakpoint_from_kind". */ | |
270 | ||
271 | static const gdb_byte * | |
272 | riscv_sw_breakpoint_from_kind (int kind, int *size) | |
273 | { | |
274 | *size = kind; | |
275 | switch (kind) | |
276 | { | |
277 | case sizeof (riscv_ibreakpoint): | |
278 | return (const gdb_byte *) &riscv_ibreakpoint; | |
279 | default: | |
280 | return (const gdb_byte *) &riscv_cbreakpoint; | |
281 | } | |
282 | } | |
283 | ||
284 | /* Implementation of linux_target_ops method "breakpoint_at". */ | |
285 | ||
286 | static int | |
287 | riscv_breakpoint_at (CORE_ADDR pc) | |
288 | { | |
289 | union | |
290 | { | |
291 | gdb_byte bytes[2]; | |
292 | uint16_t insn; | |
293 | } | |
294 | buf; | |
295 | ||
296 | if (target_read_memory (pc, buf.bytes, sizeof (buf.insn)) == 0 | |
297 | && (buf.insn == riscv_cbreakpoint | |
298 | || (buf.insn == riscv_ibreakpoint[0] | |
299 | && target_read_memory (pc + sizeof (buf.insn), buf.bytes, | |
300 | sizeof (buf.insn)) == 0 | |
301 | && buf.insn == riscv_ibreakpoint[1]))) | |
302 | return 1; | |
303 | else | |
304 | return 0; | |
305 | } | |
306 | ||
307 | /* RISC-V/Linux target operations. */ | |
308 | struct linux_target_ops the_low_target = | |
309 | { | |
bf84f706 MR |
310 | riscv_sw_breakpoint_from_kind, |
311 | NULL, /* get_next_pcs */ | |
312 | 0, /* decr_pc_after_break */ | |
313 | riscv_breakpoint_at, | |
314 | }; | |
315 | ||
ef0478f6 TBA |
316 | /* The linux target ops object. */ |
317 | ||
318 | linux_process_target *the_linux_target = &the_riscv_target; | |
319 | ||
bf84f706 MR |
320 | /* Initialize the RISC-V/Linux target. */ |
321 | ||
322 | void | |
323 | initialize_low_arch () | |
324 | { | |
325 | initialize_regsets_info (&riscv_regsets_info); | |
326 | } |