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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 | ||
33 | /* Implementation of linux_target_ops method "arch_setup". */ | |
34 | ||
35 | static void | |
36 | riscv_arch_setup () | |
37 | { | |
38 | static const char *expedite_regs[] = { "sp", "pc", NULL }; | |
39 | ||
40 | const riscv_gdbarch_features features | |
41 | = riscv_linux_read_features (lwpid_of (current_thread)); | |
42 | target_desc *tdesc = riscv_create_target_description (features); | |
43 | ||
44 | if (!tdesc->expedite_regs) | |
45 | init_target_desc (tdesc, expedite_regs); | |
46 | current_process ()->tdesc = tdesc; | |
47 | } | |
48 | ||
49 | /* Collect GPRs from REGCACHE into BUF. */ | |
50 | ||
51 | static void | |
52 | riscv_fill_gregset (struct regcache *regcache, void *buf) | |
53 | { | |
54 | const struct target_desc *tdesc = regcache->tdesc; | |
55 | elf_gregset_t *regset = (elf_gregset_t *) buf; | |
56 | int regno = find_regno (tdesc, "zero"); | |
57 | int i; | |
58 | ||
59 | collect_register_by_name (regcache, "pc", *regset); | |
60 | for (i = 1; i < ARRAY_SIZE (*regset); i++) | |
61 | collect_register (regcache, regno + i, *regset + i); | |
62 | } | |
63 | ||
64 | /* Supply GPRs from BUF into REGCACHE. */ | |
65 | ||
66 | static void | |
67 | riscv_store_gregset (struct regcache *regcache, const void *buf) | |
68 | { | |
69 | const elf_gregset_t *regset = (const elf_gregset_t *) buf; | |
70 | const struct target_desc *tdesc = regcache->tdesc; | |
71 | int regno = find_regno (tdesc, "zero"); | |
72 | int i; | |
73 | ||
74 | supply_register_by_name (regcache, "pc", *regset); | |
75 | supply_register_zeroed (regcache, regno); | |
76 | for (i = 1; i < ARRAY_SIZE (*regset); i++) | |
77 | supply_register (regcache, regno + i, *regset + i); | |
78 | } | |
79 | ||
80 | /* Collect FPRs from REGCACHE into BUF. */ | |
81 | ||
82 | static void | |
83 | riscv_fill_fpregset (struct regcache *regcache, void *buf) | |
84 | { | |
85 | const struct target_desc *tdesc = regcache->tdesc; | |
86 | int regno = find_regno (tdesc, "ft0"); | |
87 | int flen = register_size (regcache->tdesc, regno); | |
88 | gdb_byte *regbuf = (gdb_byte *) buf; | |
89 | int i; | |
90 | ||
91 | for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen) | |
92 | collect_register (regcache, regno + i, regbuf); | |
93 | collect_register_by_name (regcache, "fcsr", regbuf); | |
94 | } | |
95 | ||
96 | /* Supply FPRs from BUF into REGCACHE. */ | |
97 | ||
98 | static void | |
99 | riscv_store_fpregset (struct regcache *regcache, const void *buf) | |
100 | { | |
101 | const struct target_desc *tdesc = regcache->tdesc; | |
102 | int regno = find_regno (tdesc, "ft0"); | |
103 | int flen = register_size (regcache->tdesc, regno); | |
104 | const gdb_byte *regbuf = (const gdb_byte *) buf; | |
105 | int i; | |
106 | ||
107 | for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen) | |
108 | supply_register (regcache, regno + i, regbuf); | |
109 | supply_register_by_name (regcache, "fcsr", regbuf); | |
110 | } | |
111 | ||
112 | /* RISC-V/Linux regsets. FPRs are optional and come in different sizes, | |
113 | so define multiple regsets for them marking them all as OPTIONAL_REGS | |
114 | rather than FP_REGS, so that "regsets_fetch_inferior_registers" picks | |
115 | the right one according to size. */ | |
116 | static struct regset_info riscv_regsets[] = { | |
117 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS, | |
118 | sizeof (elf_gregset_t), GENERAL_REGS, | |
119 | riscv_fill_gregset, riscv_store_gregset }, | |
120 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, | |
121 | sizeof (struct __riscv_mc_q_ext_state), OPTIONAL_REGS, | |
122 | riscv_fill_fpregset, riscv_store_fpregset }, | |
123 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, | |
124 | sizeof (struct __riscv_mc_d_ext_state), OPTIONAL_REGS, | |
125 | riscv_fill_fpregset, riscv_store_fpregset }, | |
126 | { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, | |
127 | sizeof (struct __riscv_mc_f_ext_state), OPTIONAL_REGS, | |
128 | riscv_fill_fpregset, riscv_store_fpregset }, | |
129 | NULL_REGSET | |
130 | }; | |
131 | ||
132 | /* RISC-V/Linux regset information. */ | |
133 | static struct regsets_info riscv_regsets_info = | |
134 | { | |
135 | riscv_regsets, /* regsets */ | |
136 | 0, /* num_regsets */ | |
137 | NULL, /* disabled_regsets */ | |
138 | }; | |
139 | ||
140 | /* Definition of linux_target_ops data member "regs_info". */ | |
141 | static struct regs_info riscv_regs = | |
142 | { | |
143 | NULL, /* regset_bitmap */ | |
144 | NULL, /* usrregs */ | |
145 | &riscv_regsets_info, | |
146 | }; | |
147 | ||
148 | /* Implementation of linux_target_ops method "regs_info". */ | |
149 | ||
150 | static const struct regs_info * | |
151 | riscv_regs_info () | |
152 | { | |
153 | return &riscv_regs; | |
154 | } | |
155 | ||
156 | /* Implementation of linux_target_ops method "fetch_register". */ | |
157 | ||
158 | static int | |
159 | riscv_fetch_register (struct regcache *regcache, int regno) | |
160 | { | |
161 | const struct target_desc *tdesc = regcache->tdesc; | |
162 | ||
163 | if (regno != find_regno (tdesc, "zero")) | |
164 | return 0; | |
165 | supply_register_zeroed (regcache, regno); | |
166 | return 1; | |
167 | } | |
168 | ||
169 | /* Implementation of linux_target_ops method "get_pc". */ | |
170 | ||
171 | static CORE_ADDR | |
172 | riscv_get_pc (struct regcache *regcache) | |
173 | { | |
174 | elf_gregset_t regset; | |
175 | ||
176 | if (sizeof (regset[0]) == 8) | |
177 | return linux_get_pc_64bit (regcache); | |
178 | else | |
179 | return linux_get_pc_32bit (regcache); | |
180 | } | |
181 | ||
182 | /* Implementation of linux_target_ops method "set_pc". */ | |
183 | ||
184 | static void | |
185 | riscv_set_pc (struct regcache *regcache, CORE_ADDR newpc) | |
186 | { | |
187 | elf_gregset_t regset; | |
188 | ||
189 | if (sizeof (regset[0]) == 8) | |
190 | linux_set_pc_64bit (regcache, newpc); | |
191 | else | |
192 | linux_set_pc_32bit (regcache, newpc); | |
193 | } | |
194 | ||
195 | /* Correct in either endianness. */ | |
196 | static const uint16_t riscv_ibreakpoint[] = { 0x0073, 0x0010 }; | |
197 | static const uint16_t riscv_cbreakpoint = 0x9002; | |
198 | ||
199 | /* Implementation of linux_target_ops method "breakpoint_kind_from_pc". */ | |
200 | ||
201 | static int | |
202 | riscv_breakpoint_kind_from_pc (CORE_ADDR *pcptr) | |
203 | { | |
204 | union | |
205 | { | |
206 | gdb_byte bytes[2]; | |
207 | uint16_t insn; | |
208 | } | |
209 | buf; | |
210 | ||
211 | if (target_read_memory (*pcptr, buf.bytes, sizeof (buf.insn)) == 0 | |
212 | && riscv_insn_length (buf.insn == sizeof (riscv_ibreakpoint))) | |
213 | return sizeof (riscv_ibreakpoint); | |
214 | else | |
215 | return sizeof (riscv_cbreakpoint); | |
216 | } | |
217 | ||
218 | /* Implementation of linux_target_ops method "sw_breakpoint_from_kind". */ | |
219 | ||
220 | static const gdb_byte * | |
221 | riscv_sw_breakpoint_from_kind (int kind, int *size) | |
222 | { | |
223 | *size = kind; | |
224 | switch (kind) | |
225 | { | |
226 | case sizeof (riscv_ibreakpoint): | |
227 | return (const gdb_byte *) &riscv_ibreakpoint; | |
228 | default: | |
229 | return (const gdb_byte *) &riscv_cbreakpoint; | |
230 | } | |
231 | } | |
232 | ||
233 | /* Implementation of linux_target_ops method "breakpoint_at". */ | |
234 | ||
235 | static int | |
236 | riscv_breakpoint_at (CORE_ADDR pc) | |
237 | { | |
238 | union | |
239 | { | |
240 | gdb_byte bytes[2]; | |
241 | uint16_t insn; | |
242 | } | |
243 | buf; | |
244 | ||
245 | if (target_read_memory (pc, buf.bytes, sizeof (buf.insn)) == 0 | |
246 | && (buf.insn == riscv_cbreakpoint | |
247 | || (buf.insn == riscv_ibreakpoint[0] | |
248 | && target_read_memory (pc + sizeof (buf.insn), buf.bytes, | |
249 | sizeof (buf.insn)) == 0 | |
250 | && buf.insn == riscv_ibreakpoint[1]))) | |
251 | return 1; | |
252 | else | |
253 | return 0; | |
254 | } | |
255 | ||
256 | /* RISC-V/Linux target operations. */ | |
257 | struct linux_target_ops the_low_target = | |
258 | { | |
259 | riscv_arch_setup, | |
260 | riscv_regs_info, | |
261 | NULL, /* cannot_fetch_register */ | |
262 | NULL, /* cannot_store_register */ | |
263 | riscv_fetch_register, | |
264 | riscv_get_pc, | |
265 | riscv_set_pc, | |
266 | riscv_breakpoint_kind_from_pc, | |
267 | riscv_sw_breakpoint_from_kind, | |
268 | NULL, /* get_next_pcs */ | |
269 | 0, /* decr_pc_after_break */ | |
270 | riscv_breakpoint_at, | |
271 | }; | |
272 | ||
273 | /* Initialize the RISC-V/Linux target. */ | |
274 | ||
275 | void | |
276 | initialize_low_arch () | |
277 | { | |
278 | initialize_regsets_info (&riscv_regsets_info); | |
279 | } |