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1 | /* Native-dependent code for GNU/Linux x86 (i386 and x86-64). |
2 | ||
32d0add0 | 3 | Copyright (C) 1999-2015 Free Software Foundation, Inc. |
040baaf6 GB |
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 "elf/common.h" | |
23 | #include "gdb_proc_service.h" | |
24 | #include <sys/ptrace.h> | |
25 | #include <sys/user.h> | |
26 | #include <sys/procfs.h> | |
72fde3df | 27 | #include <sys/uio.h> |
040baaf6 | 28 | |
df7e5265 | 29 | #include "x86-nat.h" |
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30 | #include "linux-nat.h" |
31 | #ifndef __x86_64__ | |
32 | #include "i386-linux-nat.h" | |
33 | #endif | |
34 | #include "x86-linux-nat.h" | |
35 | #include "i386-linux-tdep.h" | |
36 | #ifdef __x86_64__ | |
37 | #include "amd64-linux-tdep.h" | |
38 | #endif | |
df7e5265 | 39 | #include "x86-xstate.h" |
040baaf6 | 40 | #include "nat/linux-btrace.h" |
7b669087 | 41 | #include "nat/linux-nat.h" |
4b134ca1 | 42 | #include "nat/x86-linux.h" |
8e5d4070 | 43 | #include "nat/x86-linux-dregs.h" |
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44 | |
45 | /* Per-thread arch-specific data we want to keep. */ | |
46 | ||
47 | struct arch_lwp_info | |
48 | { | |
49 | /* Non-zero if our copy differs from what's recorded in the thread. */ | |
50 | int debug_registers_changed; | |
51 | }; | |
52 | ||
53 | /* Does the current host support PTRACE_GETREGSET? */ | |
54 | int have_ptrace_getregset = -1; | |
040baaf6 GB |
55 | \f |
56 | ||
57 | /* linux_nat_new_fork hook. */ | |
58 | ||
59 | static void | |
60 | x86_linux_new_fork (struct lwp_info *parent, pid_t child_pid) | |
61 | { | |
62 | pid_t parent_pid; | |
df7e5265 GB |
63 | struct x86_debug_reg_state *parent_state; |
64 | struct x86_debug_reg_state *child_state; | |
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65 | |
66 | /* NULL means no watchpoint has ever been set in the parent. In | |
67 | that case, there's nothing to do. */ | |
68 | if (parent->arch_private == NULL) | |
69 | return; | |
70 | ||
71 | /* Linux kernel before 2.6.33 commit | |
72 | 72f674d203cd230426437cdcf7dd6f681dad8b0d | |
73 | will inherit hardware debug registers from parent | |
74 | on fork/vfork/clone. Newer Linux kernels create such tasks with | |
75 | zeroed debug registers. | |
76 | ||
77 | GDB core assumes the child inherits the watchpoints/hw | |
78 | breakpoints of the parent, and will remove them all from the | |
79 | forked off process. Copy the debug registers mirrors into the | |
80 | new process so that all breakpoints and watchpoints can be | |
81 | removed together. The debug registers mirror will become zeroed | |
82 | in the end before detaching the forked off process, thus making | |
83 | this compatible with older Linux kernels too. */ | |
84 | ||
85 | parent_pid = ptid_get_pid (parent->ptid); | |
df7e5265 GB |
86 | parent_state = x86_debug_reg_state (parent_pid); |
87 | child_state = x86_debug_reg_state (child_pid); | |
040baaf6 GB |
88 | *child_state = *parent_state; |
89 | } | |
90 | \f | |
91 | ||
92 | static void (*super_post_startup_inferior) (struct target_ops *self, | |
93 | ptid_t ptid); | |
94 | ||
95 | static void | |
96 | x86_linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid) | |
97 | { | |
df7e5265 | 98 | x86_cleanup_dregs (); |
040baaf6 GB |
99 | super_post_startup_inferior (self, ptid); |
100 | } | |
101 | ||
102 | #ifdef __x86_64__ | |
103 | /* Value of CS segment register: | |
104 | 64bit process: 0x33 | |
105 | 32bit process: 0x23 */ | |
106 | #define AMD64_LINUX_USER64_CS 0x33 | |
107 | ||
108 | /* Value of DS segment register: | |
109 | LP64 process: 0x0 | |
110 | X32 process: 0x2b */ | |
111 | #define AMD64_LINUX_X32_DS 0x2b | |
112 | #endif | |
113 | ||
114 | /* Get Linux/x86 target description from running target. */ | |
115 | ||
116 | static const struct target_desc * | |
117 | x86_linux_read_description (struct target_ops *ops) | |
118 | { | |
119 | int tid; | |
120 | int is_64bit = 0; | |
121 | #ifdef __x86_64__ | |
122 | int is_x32; | |
123 | #endif | |
124 | static uint64_t xcr0; | |
125 | uint64_t xcr0_features_bits; | |
126 | ||
127 | /* GNU/Linux LWP ID's are process ID's. */ | |
128 | tid = ptid_get_lwp (inferior_ptid); | |
129 | if (tid == 0) | |
130 | tid = ptid_get_pid (inferior_ptid); /* Not a threaded program. */ | |
131 | ||
132 | #ifdef __x86_64__ | |
133 | { | |
134 | unsigned long cs; | |
135 | unsigned long ds; | |
136 | ||
137 | /* Get CS register. */ | |
138 | errno = 0; | |
139 | cs = ptrace (PTRACE_PEEKUSER, tid, | |
140 | offsetof (struct user_regs_struct, cs), 0); | |
141 | if (errno != 0) | |
142 | perror_with_name (_("Couldn't get CS register")); | |
143 | ||
144 | is_64bit = cs == AMD64_LINUX_USER64_CS; | |
145 | ||
146 | /* Get DS register. */ | |
147 | errno = 0; | |
148 | ds = ptrace (PTRACE_PEEKUSER, tid, | |
149 | offsetof (struct user_regs_struct, ds), 0); | |
150 | if (errno != 0) | |
151 | perror_with_name (_("Couldn't get DS register")); | |
152 | ||
153 | is_x32 = ds == AMD64_LINUX_X32_DS; | |
154 | ||
155 | if (sizeof (void *) == 4 && is_64bit && !is_x32) | |
156 | error (_("Can't debug 64-bit process with 32-bit GDB")); | |
157 | } | |
158 | #elif HAVE_PTRACE_GETFPXREGS | |
159 | if (have_ptrace_getfpxregs == -1) | |
160 | { | |
161 | elf_fpxregset_t fpxregs; | |
162 | ||
163 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0) | |
164 | { | |
165 | have_ptrace_getfpxregs = 0; | |
166 | have_ptrace_getregset = 0; | |
167 | return tdesc_i386_mmx_linux; | |
168 | } | |
169 | } | |
170 | #endif | |
171 | ||
172 | if (have_ptrace_getregset == -1) | |
173 | { | |
df7e5265 | 174 | uint64_t xstateregs[(X86_XSTATE_SSE_SIZE / sizeof (uint64_t))]; |
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175 | struct iovec iov; |
176 | ||
177 | iov.iov_base = xstateregs; | |
178 | iov.iov_len = sizeof (xstateregs); | |
179 | ||
180 | /* Check if PTRACE_GETREGSET works. */ | |
181 | if (ptrace (PTRACE_GETREGSET, tid, | |
182 | (unsigned int) NT_X86_XSTATE, &iov) < 0) | |
183 | have_ptrace_getregset = 0; | |
184 | else | |
185 | { | |
186 | have_ptrace_getregset = 1; | |
187 | ||
188 | /* Get XCR0 from XSAVE extended state. */ | |
189 | xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET | |
190 | / sizeof (uint64_t))]; | |
191 | } | |
192 | } | |
193 | ||
194 | /* Check the native XCR0 only if PTRACE_GETREGSET is available. If | |
195 | PTRACE_GETREGSET is not available then set xcr0_features_bits to | |
196 | zero so that the "no-features" descriptions are returned by the | |
197 | switches below. */ | |
198 | if (have_ptrace_getregset) | |
df7e5265 | 199 | xcr0_features_bits = xcr0 & X86_XSTATE_ALL_MASK; |
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200 | else |
201 | xcr0_features_bits = 0; | |
202 | ||
203 | if (is_64bit) | |
204 | { | |
205 | #ifdef __x86_64__ | |
206 | switch (xcr0_features_bits) | |
207 | { | |
df7e5265 GB |
208 | case X86_XSTATE_MPX_AVX512_MASK: |
209 | case X86_XSTATE_AVX512_MASK: | |
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210 | if (is_x32) |
211 | return tdesc_x32_avx512_linux; | |
212 | else | |
213 | return tdesc_amd64_avx512_linux; | |
df7e5265 | 214 | case X86_XSTATE_MPX_MASK: |
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215 | if (is_x32) |
216 | return tdesc_x32_avx_linux; /* No MPX on x32 using AVX. */ | |
217 | else | |
218 | return tdesc_amd64_mpx_linux; | |
df7e5265 | 219 | case X86_XSTATE_AVX_MASK: |
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220 | if (is_x32) |
221 | return tdesc_x32_avx_linux; | |
222 | else | |
223 | return tdesc_amd64_avx_linux; | |
224 | default: | |
225 | if (is_x32) | |
226 | return tdesc_x32_linux; | |
227 | else | |
228 | return tdesc_amd64_linux; | |
229 | } | |
230 | #endif | |
231 | } | |
232 | else | |
233 | { | |
234 | switch (xcr0_features_bits) | |
235 | { | |
df7e5265 GB |
236 | case X86_XSTATE_MPX_AVX512_MASK: |
237 | case X86_XSTATE_AVX512_MASK: | |
040baaf6 | 238 | return tdesc_i386_avx512_linux; |
df7e5265 | 239 | case X86_XSTATE_MPX_MASK: |
040baaf6 | 240 | return tdesc_i386_mpx_linux; |
df7e5265 | 241 | case X86_XSTATE_AVX_MASK: |
040baaf6 GB |
242 | return tdesc_i386_avx_linux; |
243 | default: | |
244 | return tdesc_i386_linux; | |
245 | } | |
246 | } | |
247 | ||
248 | gdb_assert_not_reached ("failed to return tdesc"); | |
249 | } | |
250 | \f | |
251 | ||
252 | /* Enable branch tracing. */ | |
253 | ||
254 | static struct btrace_target_info * | |
f4abbc16 MM |
255 | x86_linux_enable_btrace (struct target_ops *self, ptid_t ptid, |
256 | const struct btrace_config *conf) | |
040baaf6 GB |
257 | { |
258 | struct btrace_target_info *tinfo; | |
259 | struct gdbarch *gdbarch; | |
260 | ||
261 | errno = 0; | |
f4abbc16 | 262 | tinfo = linux_enable_btrace (ptid, conf); |
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263 | |
264 | if (tinfo == NULL) | |
265 | error (_("Could not enable branch tracing for %s: %s."), | |
266 | target_pid_to_str (ptid), safe_strerror (errno)); | |
267 | ||
268 | /* Fill in the size of a pointer in bits. */ | |
d68e53f4 MM |
269 | if (tinfo->ptr_bits == 0) |
270 | { | |
271 | gdbarch = target_thread_architecture (ptid); | |
272 | tinfo->ptr_bits = gdbarch_ptr_bit (gdbarch); | |
273 | } | |
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274 | return tinfo; |
275 | } | |
276 | ||
277 | /* Disable branch tracing. */ | |
278 | ||
279 | static void | |
280 | x86_linux_disable_btrace (struct target_ops *self, | |
281 | struct btrace_target_info *tinfo) | |
282 | { | |
283 | enum btrace_error errcode = linux_disable_btrace (tinfo); | |
284 | ||
285 | if (errcode != BTRACE_ERR_NONE) | |
286 | error (_("Could not disable branch tracing.")); | |
287 | } | |
288 | ||
289 | /* Teardown branch tracing. */ | |
290 | ||
291 | static void | |
292 | x86_linux_teardown_btrace (struct target_ops *self, | |
293 | struct btrace_target_info *tinfo) | |
294 | { | |
295 | /* Ignore errors. */ | |
296 | linux_disable_btrace (tinfo); | |
297 | } | |
298 | ||
299 | static enum btrace_error | |
300 | x86_linux_read_btrace (struct target_ops *self, | |
734b0e4b | 301 | struct btrace_data *data, |
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302 | struct btrace_target_info *btinfo, |
303 | enum btrace_read_type type) | |
304 | { | |
305 | return linux_read_btrace (data, btinfo, type); | |
306 | } | |
f4abbc16 MM |
307 | |
308 | /* See to_btrace_conf in target.h. */ | |
309 | ||
310 | static const struct btrace_config * | |
311 | x86_linux_btrace_conf (struct target_ops *self, | |
312 | const struct btrace_target_info *btinfo) | |
313 | { | |
314 | return linux_btrace_conf (btinfo); | |
315 | } | |
316 | ||
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317 | \f |
318 | ||
319 | /* Helper for ps_get_thread_area. Sets BASE_ADDR to a pointer to | |
320 | the thread local storage (or its descriptor) and returns PS_OK | |
321 | on success. Returns PS_ERR on failure. */ | |
322 | ||
323 | ps_err_e | |
324 | x86_linux_get_thread_area (pid_t pid, void *addr, unsigned int *base_addr) | |
325 | { | |
326 | /* NOTE: cagney/2003-08-26: The definition of this buffer is found | |
327 | in the kernel header <asm-i386/ldt.h>. It, after padding, is 4 x | |
328 | 4 byte integers in size: `entry_number', `base_addr', `limit', | |
329 | and a bunch of status bits. | |
330 | ||
331 | The values returned by this ptrace call should be part of the | |
332 | regcache buffer, and ps_get_thread_area should channel its | |
333 | request through the regcache. That way remote targets could | |
334 | provide the value using the remote protocol and not this direct | |
335 | call. | |
336 | ||
337 | Is this function needed? I'm guessing that the `base' is the | |
338 | address of a descriptor that libthread_db uses to find the | |
339 | thread local address base that GDB needs. Perhaps that | |
340 | descriptor is defined by the ABI. Anyway, given that | |
341 | libthread_db calls this function without prompting (gdb | |
342 | requesting tls base) I guess it needs info in there anyway. */ | |
343 | unsigned int desc[4]; | |
344 | ||
345 | /* This code assumes that "int" is 32 bits and that | |
346 | GET_THREAD_AREA returns no more than 4 int values. */ | |
347 | gdb_assert (sizeof (int) == 4); | |
348 | ||
349 | #ifndef PTRACE_GET_THREAD_AREA | |
350 | #define PTRACE_GET_THREAD_AREA 25 | |
351 | #endif | |
352 | ||
353 | if (ptrace (PTRACE_GET_THREAD_AREA, pid, addr, &desc) < 0) | |
354 | return PS_ERR; | |
355 | ||
356 | *base_addr = desc[1]; | |
357 | return PS_OK; | |
358 | } | |
359 | \f | |
360 | ||
361 | /* Create an x86 GNU/Linux target. */ | |
362 | ||
363 | struct target_ops * | |
364 | x86_linux_create_target (void) | |
365 | { | |
366 | /* Fill in the generic GNU/Linux methods. */ | |
367 | struct target_ops *t = linux_target (); | |
368 | ||
369 | /* Initialize the debug register function vectors. */ | |
df7e5265 GB |
370 | x86_use_watchpoints (t); |
371 | x86_dr_low.set_control = x86_linux_dr_set_control; | |
372 | x86_dr_low.set_addr = x86_linux_dr_set_addr; | |
373 | x86_dr_low.get_addr = x86_linux_dr_get_addr; | |
374 | x86_dr_low.get_status = x86_linux_dr_get_status; | |
375 | x86_dr_low.get_control = x86_linux_dr_get_control; | |
376 | x86_set_debug_register_length (sizeof (void *)); | |
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377 | |
378 | /* Override the GNU/Linux inferior startup hook. */ | |
379 | super_post_startup_inferior = t->to_post_startup_inferior; | |
380 | t->to_post_startup_inferior = x86_linux_child_post_startup_inferior; | |
381 | ||
382 | /* Add the description reader. */ | |
383 | t->to_read_description = x86_linux_read_description; | |
384 | ||
385 | /* Add btrace methods. */ | |
386 | t->to_supports_btrace = linux_supports_btrace; | |
387 | t->to_enable_btrace = x86_linux_enable_btrace; | |
388 | t->to_disable_btrace = x86_linux_disable_btrace; | |
389 | t->to_teardown_btrace = x86_linux_teardown_btrace; | |
390 | t->to_read_btrace = x86_linux_read_btrace; | |
f4abbc16 | 391 | t->to_btrace_conf = x86_linux_btrace_conf; |
040baaf6 GB |
392 | |
393 | return t; | |
394 | } | |
395 | ||
396 | /* Add an x86 GNU/Linux target. */ | |
397 | ||
398 | void | |
399 | x86_linux_add_target (struct target_ops *t) | |
400 | { | |
401 | linux_nat_add_target (t); | |
402 | linux_nat_set_new_thread (t, x86_linux_new_thread); | |
403 | linux_nat_set_new_fork (t, x86_linux_new_fork); | |
df7e5265 | 404 | linux_nat_set_forget_process (t, x86_forget_process); |
040baaf6 GB |
405 | linux_nat_set_prepare_to_resume (t, x86_linux_prepare_to_resume); |
406 | } |