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i386-bsd-nat.c
Go to the documentation of this file.
1/* Native-dependent code for modern i386 BSD's.
2
3 Copyright (C) 2000-2023 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 "defs.h"
21#include "inferior.h"
22#include "regcache.h"
23
24#include <signal.h>
25#include <sys/types.h>
26#include <sys/ptrace.h>
27#include <machine/reg.h>
28#include <machine/frame.h>
29
30#include "i386-tdep.h"
31#include "i387-tdep.h"
32#include "x86-bsd-nat.h"
33#include "i386-bsd-nat.h"
34#include "inf-ptrace.h"
35
36
37static PTRACE_TYPE_RET
38gdb_ptrace (PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr,
40{
41#ifdef __NetBSD__
42 gdb_assert (data == 0);
43 /* Support for NetBSD threads: unlike other ptrace implementations in this
44 file, NetBSD requires that we pass both the pid and lwp. */
45 return ptrace (request, ptid.pid (), addr, ptid.lwp ());
46#else
47 pid_t pid = get_ptrace_pid (ptid);
48 return ptrace (request, pid, addr, data);
49#endif
50}
51
52/* In older BSD versions we cannot get at some of the segment
53 registers. FreeBSD for example didn't support the %fs and %gs
54 registers until the 3.0 release. We have autoconf checks for their
55 presence, and deal gracefully with their absence. */
56
57/* Offset in `struct reg' where MEMBER is stored. */
58#define REG_OFFSET(member) offsetof (struct reg, member)
59
60/* At i386bsd_reg_offset[REGNUM] you'll find the offset in `struct
61 reg' where the GDB register REGNUM is stored. Unsupported
62 registers are marked with `-1'. */
64{
65 REG_OFFSET (r_eax),
66 REG_OFFSET (r_ecx),
67 REG_OFFSET (r_edx),
68 REG_OFFSET (r_ebx),
69 REG_OFFSET (r_esp),
70 REG_OFFSET (r_ebp),
71 REG_OFFSET (r_esi),
72 REG_OFFSET (r_edi),
73 REG_OFFSET (r_eip),
74 REG_OFFSET (r_eflags),
75 REG_OFFSET (r_cs),
76 REG_OFFSET (r_ss),
77 REG_OFFSET (r_ds),
78 REG_OFFSET (r_es),
79#ifdef HAVE_STRUCT_REG_R_FS
80 REG_OFFSET (r_fs),
81#else
82 -1,
83#endif
84#ifdef HAVE_STRUCT_REG_R_GS
85 REG_OFFSET (r_gs)
86#else
87 -1
88#endif
89};
90
91/* Macro to determine if a register is fetched with PT_GETREGS. */
92#define GETREGS_SUPPLIES(regnum) \
93 ((0 <= (regnum) && (regnum) <= 15))
94
95/* Set to 1 if the kernel supports PT_GETXMMREGS. Initialized to -1
96 so that we try PT_GETXMMREGS the first time around. */
97static int have_ptrace_xmmregs = -1;
98
99
100/* Supply the general-purpose registers in GREGS, to REGCACHE. */
101
102static void
103i386bsd_supply_gregset (struct regcache *regcache, const void *gregs)
104{
105 const char *regs = (const char *) gregs;
106 int regnum;
107
108 for (regnum = 0; regnum < ARRAY_SIZE (i386bsd_r_reg_offset); regnum++)
109 {
110 int offset = i386bsd_r_reg_offset[regnum];
111
112 if (offset != -1)
113 regcache->raw_supply (regnum, regs + offset);
114 }
115}
116
117/* Collect register REGNUM from REGCACHE and store its contents in
118 GREGS. If REGNUM is -1, collect and store all appropriate
119 registers. */
120
121static void
123 void *gregs, int regnum)
124{
125 char *regs = (char *) gregs;
126 int i;
127
128 for (i = 0; i < ARRAY_SIZE (i386bsd_r_reg_offset); i++)
129 {
130 if (regnum == -1 || regnum == i)
131 {
132 int offset = i386bsd_r_reg_offset[i];
133
134 if (offset != -1)
135 regcache->raw_collect (i, regs + offset);
136 }
137 }
138}
139
140/* Fetch register REGNUM from the inferior. If REGNUM is -1, do this
141 for all registers (including the floating point registers). */
142
143void
145{
146 ptid_t ptid = regcache->ptid ();
147
148 if (regnum == -1 || GETREGS_SUPPLIES (regnum))
149 {
150 struct reg regs;
151
152 if (gdb_ptrace (PT_GETREGS, ptid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
153 perror_with_name (_("Couldn't get registers"));
154
156 if (regnum != -1)
157 return;
158 }
159
160 if (regnum == -1 || regnum >= I386_ST0_REGNUM)
161 {
162 struct fpreg fpregs;
163 char xmmregs[512];
164
165 if (have_ptrace_xmmregs != 0
166 && gdb_ptrace(PT_GETXMMREGS, ptid,
167 (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
168 {
170 i387_supply_fxsave (regcache, -1, xmmregs);
171 }
172 else
173 {
175 if (gdb_ptrace (PT_GETFPREGS, ptid,
176 (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
177 perror_with_name (_("Couldn't get floating point status"));
178
179 i387_supply_fsave (regcache, -1, &fpregs);
180 }
181 }
182}
183
184/* Store register REGNUM back into the inferior. If REGNUM is -1, do
185 this for all registers (including the floating point registers). */
186
187void
189{
190 ptid_t ptid = regcache->ptid ();
191
192 if (regnum == -1 || GETREGS_SUPPLIES (regnum))
193 {
194 struct reg regs;
195
196 if (gdb_ptrace (PT_GETREGS, ptid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
197 perror_with_name (_("Couldn't get registers"));
198
200
201 if (gdb_ptrace (PT_SETREGS, ptid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
202 perror_with_name (_("Couldn't write registers"));
203
204 if (regnum != -1)
205 return;
206 }
207
208 if (regnum == -1 || regnum >= I386_ST0_REGNUM)
209 {
210 struct fpreg fpregs;
211 char xmmregs[512];
212
213 if (have_ptrace_xmmregs != 0
214 && gdb_ptrace(PT_GETXMMREGS, ptid,
215 (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
216 {
218
220
221 if (gdb_ptrace (PT_SETXMMREGS, ptid,
222 (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
223 perror_with_name (_("Couldn't write XMM registers"));
224 }
225 else
226 {
228 if (gdb_ptrace (PT_GETFPREGS, ptid,
229 (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
230 perror_with_name (_("Couldn't get floating point status"));
231
233
234 if (gdb_ptrace (PT_SETFPREGS, ptid,
235 (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
236 perror_with_name (_("Couldn't write floating point status"));
237 }
238 }
239}
240
242void
244{
245 /* To support the recognition of signal handlers, i386-bsd-tdep.c
246 hardcodes some constants. Inclusion of this file means that we
247 are compiling a native debugger, which means that we can use the
248 system header files and sysctl(3) to get at the relevant
249 information. */
250
251#if defined (OpenBSD)
252#define SC_REG_OFFSET i386obsd_sc_reg_offset
253#endif
254
255#ifdef SC_REG_OFFSET
256
257 /* We only check the program counter, stack pointer and frame
258 pointer since these members of `struct sigcontext' are essential
259 for providing backtraces. More checks could be added, but would
260 involve adding configure checks for the appropriate structure
261 members, since older BSD's don't provide all of them. */
262
263#define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
264#define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
265#define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
266
267 /* Override the default value for the offset of the program counter
268 in the sigcontext structure. */
269 int offset = offsetof (struct sigcontext, sc_pc);
270
271 if (SC_PC_OFFSET != offset)
272 {
273 warning (_("\
274offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
275Please report this to <bug-gdb@gnu.org>."),
276 offset, SC_PC_OFFSET);
277 }
278
279 SC_PC_OFFSET = offset;
280
281 /* Likewise for the stack pointer. */
282 offset = offsetof (struct sigcontext, sc_sp);
283
284 if (SC_SP_OFFSET != offset)
285 {
286 warning (_("\
287offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
288Please report this to <bug-gdb@gnu.org>."),
289 offset, SC_SP_OFFSET);
290 }
291
292 SC_SP_OFFSET = offset;
293
294 /* And the frame pointer. */
295 offset = offsetof (struct sigcontext, sc_fp);
296
297 if (SC_FP_OFFSET != offset)
298 {
299 warning (_("\
300offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
301Please report this to <bug-gdb@gnu.org>."),
302 offset, SC_FP_OFFSET);
303 }
304
305 SC_FP_OFFSET = offset;
306
307#endif /* SC_REG_OFFSET */
308}
int regnum
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
ptid_t ptid() const
Definition regcache.h:408
#define PTRACE_TYPE_RET
Definition config.h:675
#define PTRACE_TYPE_ARG1
Definition config.h:663
#define ptrace(request, pid, addr, data)
Definition gdb_ptrace.h:141
mach_port_t mach_port_t name mach_port_t mach_port_t name kern_return_t int int rusage_t pid_t pid
Definition gnu-nat.c:1791
static void i386bsd_supply_gregset(struct regcache *regcache, const void *gregs)
static PTRACE_TYPE_RET gdb_ptrace(PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr, PTRACE_TYPE_ARG4 data)
void i386bsd_store_inferior_registers(struct regcache *regcache, int regnum)
static void i386bsd_collect_gregset(const struct regcache *regcache, void *gregs, int regnum)
void _initialize_i386bsd_nat()
void i386bsd_fetch_inferior_registers(struct regcache *regcache, int regnum)
static int i386bsd_r_reg_offset[]
#define GETREGS_SUPPLIES(regnum)
#define REG_OFFSET(member)
static int have_ptrace_xmmregs
@ I386_ST0_REGNUM
Definition i386-tdep.h:297
void i387_supply_fxsave(struct regcache *regcache, int regnum, const void *fxsave)
Definition i387-tdep.c:589
void i387_collect_fxsave(const struct regcache *regcache, int regnum, void *fxsave)
Definition i387-tdep.c:673
void i387_supply_fsave(struct regcache *regcache, int regnum, const void *fsave)
Definition i387-tdep.c:440
void i387_collect_fsave(const struct regcache *regcache, int regnum, void *fsave)
Definition i387-tdep.c:495
pid_t get_ptrace_pid(ptid_t ptid)
Definition inf-ptrace.c:238
#define PTRACE_TYPE_ARG3
#define PTRACE_TYPE_ARG4