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riscv-linux-nat.c
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1/* Native-dependent code for GNU/Linux RISC-V.
2 Copyright (C) 2018-2023 Free Software Foundation, Inc.
3
4 This file is part of GDB.
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18
19#include "defs.h"
20#include "regcache.h"
21#include "gregset.h"
22#include "linux-nat.h"
23#include "riscv-tdep.h"
24#include "inferior.h"
25
26#include "elf/common.h"
27
29
30#include <sys/ptrace.h>
31
32/* Work around glibc header breakage causing ELF_NFPREG not to be usable. */
33#ifndef NFPREG
34# define NFPREG 33
35#endif
36
37/* RISC-V Linux native additions to the default linux support. */
38
40{
41public:
42 /* Add our register access methods. */
43 void fetch_registers (struct regcache *regcache, int regnum) override;
44 void store_registers (struct regcache *regcache, int regnum) override;
45
46 /* Read suitable target description. */
47 const struct target_desc *read_description () override;
48};
49
51
52/* Copy general purpose register REGNUM (or all gp regs if REGNUM == -1)
53 from regset GREGS into REGCACHE. */
54
55static void
56supply_gregset_regnum (struct regcache *regcache, const prgregset_t *gregs,
57 int regnum)
58{
59 int i;
60 const elf_greg_t *regp = *gregs;
61
62 if (regnum == -1)
63 {
64 /* We only support the integer registers and PC here. */
65 for (i = RISCV_ZERO_REGNUM + 1; i < RISCV_PC_REGNUM; i++)
66 regcache->raw_supply (i, regp + i);
67
68 /* GDB stores PC in reg 32. Linux kernel stores it in reg 0. */
70
71 /* Fill the inaccessible zero register with zero. */
73 }
74 else if (regnum == RISCV_ZERO_REGNUM)
78 else if (regnum == RISCV_PC_REGNUM)
80}
81
82/* Copy all general purpose registers from regset GREGS into REGCACHE. */
83
84void
85supply_gregset (struct regcache *regcache, const prgregset_t *gregs)
86{
88}
89
90/* Copy floating point register REGNUM (or all fp regs if REGNUM == -1)
91 from regset FPREGS into REGCACHE. */
92
93static void
94supply_fpregset_regnum (struct regcache *regcache, const prfpregset_t *fpregs,
95 int regnum)
96{
98 union
99 {
100 const prfpregset_t *fpregs;
101 const gdb_byte *buf;
102 }
103 fpbuf = { .fpregs = fpregs };
104 int i;
105
106 if (regnum == -1)
107 {
108 /* We only support the FP registers and FCSR here. */
109 for (i = RISCV_FIRST_FP_REGNUM;
111 i++, fpbuf.buf += flen)
112 regcache->raw_supply (i, fpbuf.buf);
113
114 regcache->raw_supply (RISCV_CSR_FCSR_REGNUM, fpbuf.buf);
115 }
117 {
118 fpbuf.buf += flen * (regnum - RISCV_FIRST_FP_REGNUM);
119 regcache->raw_supply (regnum, fpbuf.buf);
120 }
121 else if (regnum == RISCV_CSR_FCSR_REGNUM)
122 {
123 fpbuf.buf += flen * (RISCV_LAST_FP_REGNUM - RISCV_FIRST_FP_REGNUM + 1);
124 regcache->raw_supply (RISCV_CSR_FCSR_REGNUM, fpbuf.buf);
125 }
126}
127
128/* Copy all floating point registers from regset FPREGS into REGCACHE. */
129
130void
131supply_fpregset (struct regcache *regcache, const prfpregset_t *fpregs)
132{
133 supply_fpregset_regnum (regcache, fpregs, -1);
134}
135
136/* Copy general purpose register REGNUM (or all gp regs if REGNUM == -1)
137 from REGCACHE into regset GREGS. */
138
139void
140fill_gregset (const struct regcache *regcache, prgregset_t *gregs, int regnum)
141{
142 elf_greg_t *regp = *gregs;
143
144 if (regnum == -1)
145 {
146 /* We only support the integer registers and PC here. */
147 for (int i = RISCV_ZERO_REGNUM + 1; i < RISCV_PC_REGNUM; i++)
148 regcache->raw_collect (i, regp + i);
149
151 }
152 else if (regnum == RISCV_ZERO_REGNUM)
153 /* Nothing to do here. */
154 ;
157 else if (regnum == RISCV_PC_REGNUM)
159}
160
161/* Copy floating point register REGNUM (or all fp regs if REGNUM == -1)
162 from REGCACHE into regset FPREGS. */
163
164void
165fill_fpregset (const struct regcache *regcache, prfpregset_t *fpregs,
166 int regnum)
167{
169 union
170 {
171 prfpregset_t *fpregs;
172 gdb_byte *buf;
173 }
174 fpbuf = { .fpregs = fpregs };
175 int i;
176
177 if (regnum == -1)
178 {
179 /* We only support the FP registers and FCSR here. */
180 for (i = RISCV_FIRST_FP_REGNUM;
182 i++, fpbuf.buf += flen)
183 regcache->raw_collect (i, fpbuf.buf);
184
185 regcache->raw_collect (RISCV_CSR_FCSR_REGNUM, fpbuf.buf);
186 }
188 {
189 fpbuf.buf += flen * (regnum - RISCV_FIRST_FP_REGNUM);
190 regcache->raw_collect (regnum, fpbuf.buf);
191 }
192 else if (regnum == RISCV_CSR_FCSR_REGNUM)
193 {
194 fpbuf.buf += flen * (RISCV_LAST_FP_REGNUM - RISCV_FIRST_FP_REGNUM + 1);
195 regcache->raw_collect (RISCV_CSR_FCSR_REGNUM, fpbuf.buf);
196 }
197}
198
199/* Return a target description for the current target. */
200
201const struct target_desc *
203{
204 if (inferior_ptid == null_ptid)
205 return this->beneath ()->read_description ();
206
207 const struct riscv_gdbarch_features features
209 return riscv_lookup_target_description (features);
210}
211
212/* Fetch REGNUM (or all registers if REGNUM == -1) from the target
213 into REGCACHE using PTRACE_GETREGSET. */
214
215void
217{
218 int tid;
219
220 tid = get_ptrace_pid (regcache->ptid());
221
223 || (regnum == -1))
224 {
225 struct iovec iov;
226 elf_gregset_t regs;
227
228 iov.iov_base = &regs;
229 iov.iov_len = sizeof (regs);
230
231 if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS,
232 (PTRACE_TYPE_ARG3) &iov) == -1)
233 perror_with_name (_("Couldn't get registers"));
234 else
236 }
237
240 || (regnum == RISCV_CSR_FCSR_REGNUM)
241 || (regnum == -1))
242 {
243 struct iovec iov;
244 elf_fpregset_t regs;
245
246 iov.iov_base = &regs;
247 iov.iov_len = ELF_NFPREG * register_size (regcache->arch (),
249 gdb_assert (iov.iov_len <= sizeof (regs));
250
251 if (ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET,
252 (PTRACE_TYPE_ARG3) &iov) == -1)
253 perror_with_name (_("Couldn't get registers"));
254 else
256 }
257
258 if ((regnum == RISCV_CSR_MISA_REGNUM)
259 || (regnum == -1))
260 {
261 /* TODO: Need to add a ptrace call for this. */
262 regcache->raw_supply_zeroed (RISCV_CSR_MISA_REGNUM);
263 }
264
265 /* Access to other CSRs has potential security issues, don't support them for
266 now. */
267}
268
269/* Store REGNUM (or all registers if REGNUM == -1) to the target
270 from REGCACHE using PTRACE_SETREGSET. */
271
272void
274{
275 int tid;
276
277 tid = get_ptrace_pid (regcache->ptid ());
278
280 || (regnum == -1))
281 {
282 struct iovec iov;
283 elf_gregset_t regs;
284
285 iov.iov_base = &regs;
286 iov.iov_len = sizeof (regs);
287
288 if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS,
289 (PTRACE_TYPE_ARG3) &iov) == -1)
290 perror_with_name (_("Couldn't get registers"));
291 else
292 {
293 fill_gregset (regcache, &regs, regnum);
294
295 if (ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS,
296 (PTRACE_TYPE_ARG3) &iov) == -1)
297 perror_with_name (_("Couldn't set registers"));
298 }
299 }
300
303 || (regnum == RISCV_CSR_FCSR_REGNUM)
304 || (regnum == -1))
305 {
306 struct iovec iov;
307 elf_fpregset_t regs;
308
309 iov.iov_base = &regs;
310 iov.iov_len = ELF_NFPREG * register_size (regcache->arch (),
312 gdb_assert (iov.iov_len <= sizeof (regs));
313
314 if (ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET,
315 (PTRACE_TYPE_ARG3) &iov) == -1)
316 perror_with_name (_("Couldn't get registers"));
317 else
318 {
319 fill_fpregset (regcache, &regs, regnum);
320
321 if (ptrace (PTRACE_SETREGSET, tid, NT_FPREGSET,
322 (PTRACE_TYPE_ARG3) &iov) == -1)
323 perror_with_name (_("Couldn't set registers"));
324 }
325 }
326
327 /* Access to CSRs has potential security issues, don't support them for
328 now. */
329}
330
331/* Initialize RISC-V Linux native support. */
332
334void
int regnum
gdbarch * arch() const
Definition regcache.c:231
void raw_collect(int regnum, void *buf) const override
Definition regcache.c:1127
void raw_supply(int regnum, const void *buf) override
Definition regcache.c:1062
void raw_supply_zeroed(int regnum)
Definition regcache.c:1110
ptid_t ptid() const
Definition regcache.h:408
const struct target_desc * read_description() override
void fetch_registers(struct regcache *regcache, int regnum) override
void store_registers(struct regcache *regcache, int regnum) override
#define ptrace(request, pid, addr, data)
Definition gdb_ptrace.h:141
void add_inf_child_target(inf_child_target *target)
Definition inf-child.c:418
pid_t get_ptrace_pid(ptid_t ptid)
Definition inf-ptrace.c:238
ptid_t inferior_ptid
Definition infcmd.c:74
struct linux_nat_target * linux_target
Definition linux-nat.c:189
#define PTRACE_TYPE_ARG3
#define PTRACE_SETREGSET
#define PTRACE_GETREGSET
#define ELF_NFPREG
int register_size(struct gdbarch *gdbarch, int regnum)
Definition regcache.c:170
static riscv_linux_nat_target the_riscv_linux_nat_target
void fill_fpregset(const struct regcache *regcache, prfpregset_t *fpregs, int regnum)
static void supply_gregset_regnum(struct regcache *regcache, const prgregset_t *gregs, int regnum)
void fill_gregset(const struct regcache *regcache, prgregset_t *gregs, int regnum)
void supply_gregset(struct regcache *regcache, const prgregset_t *gregs)
static void supply_fpregset_regnum(struct regcache *regcache, const prfpregset_t *fpregs, int regnum)
void _initialize_riscv_linux_nat()
void supply_fpregset(struct regcache *regcache, const prfpregset_t *fpregs)
struct riscv_gdbarch_features riscv_linux_read_features(int tid)
@ RISCV_FIRST_FP_REGNUM
Definition riscv-tdep.h:43
@ RISCV_ZERO_REGNUM
Definition riscv-tdep.h:30
@ RISCV_LAST_FP_REGNUM
Definition riscv-tdep.h:46
@ RISCV_PC_REGNUM
Definition riscv-tdep.h:39
const target_desc * riscv_lookup_target_description(const struct riscv_gdbarch_features features)
Definition riscv.c:117
target_ops * beneath() const
Definition target.c:3041
virtual const struct target_desc * read_description() TARGET_DEFAULT_RETURN(NULL)