1 /* Native-dependent code for GNU/Linux x86 (i386 and x86-64).
3 Copyright (C) 1999-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
22 #include "elf/common.h"
23 #include "gdb_proc_service.h"
24 #include <sys/ptrace.h>
26 #include <sys/procfs.h>
30 #include "linux-nat.h"
32 #include "i386-linux-nat.h"
34 #include "x86-linux-nat.h"
35 #include "i386-linux-tdep.h"
37 #include "amd64-linux-tdep.h"
39 #include "x86-xstate.h"
40 #include "nat/linux-btrace.h"
41 #include "nat/linux-nat.h"
42 #include "nat/x86-linux.h"
43 #include "nat/x86-linux-dregs.h"
45 /* Per-thread arch-specific data we want to keep. */
49 /* Non-zero if our copy differs from what's recorded in the thread. */
50 int debug_registers_changed
;
53 /* Does the current host support PTRACE_GETREGSET? */
54 int have_ptrace_getregset
= -1;
57 /* linux_nat_new_fork hook. */
60 x86_linux_new_fork (struct lwp_info
*parent
, pid_t child_pid
)
63 struct x86_debug_reg_state
*parent_state
;
64 struct x86_debug_reg_state
*child_state
;
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
)
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.
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. */
85 parent_pid
= ptid_get_pid (parent
->ptid
);
86 parent_state
= x86_debug_reg_state (parent_pid
);
87 child_state
= x86_debug_reg_state (child_pid
);
88 *child_state
= *parent_state
;
92 static void (*super_post_startup_inferior
) (struct target_ops
*self
,
96 x86_linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
99 super_post_startup_inferior (self
, ptid
);
103 /* Value of CS segment register:
105 32bit process: 0x23 */
106 #define AMD64_LINUX_USER64_CS 0x33
108 /* Value of DS segment register:
111 #define AMD64_LINUX_X32_DS 0x2b
114 /* Get Linux/x86 target description from running target. */
116 static const struct target_desc
*
117 x86_linux_read_description (struct target_ops
*ops
)
124 static uint64_t xcr0
;
125 uint64_t xcr0_features_bits
;
127 /* GNU/Linux LWP ID's are process ID's. */
128 tid
= ptid_get_lwp (inferior_ptid
);
130 tid
= ptid_get_pid (inferior_ptid
); /* Not a threaded program. */
137 /* Get CS register. */
139 cs
= ptrace (PTRACE_PEEKUSER
, tid
,
140 offsetof (struct user_regs_struct
, cs
), 0);
142 perror_with_name (_("Couldn't get CS register"));
144 is_64bit
= cs
== AMD64_LINUX_USER64_CS
;
146 /* Get DS register. */
148 ds
= ptrace (PTRACE_PEEKUSER
, tid
,
149 offsetof (struct user_regs_struct
, ds
), 0);
151 perror_with_name (_("Couldn't get DS register"));
153 is_x32
= ds
== AMD64_LINUX_X32_DS
;
155 if (sizeof (void *) == 4 && is_64bit
&& !is_x32
)
156 error (_("Can't debug 64-bit process with 32-bit GDB"));
158 #elif HAVE_PTRACE_GETFPXREGS
159 if (have_ptrace_getfpxregs
== -1)
161 elf_fpxregset_t fpxregs
;
163 if (ptrace (PTRACE_GETFPXREGS
, tid
, 0, (int) &fpxregs
) < 0)
165 have_ptrace_getfpxregs
= 0;
166 have_ptrace_getregset
= 0;
167 return tdesc_i386_mmx_linux
;
172 if (have_ptrace_getregset
== -1)
174 uint64_t xstateregs
[(X86_XSTATE_SSE_SIZE
/ sizeof (uint64_t))];
177 iov
.iov_base
= xstateregs
;
178 iov
.iov_len
= sizeof (xstateregs
);
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;
186 have_ptrace_getregset
= 1;
188 /* Get XCR0 from XSAVE extended state. */
189 xcr0
= xstateregs
[(I386_LINUX_XSAVE_XCR0_OFFSET
190 / sizeof (uint64_t))];
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
198 if (have_ptrace_getregset
)
199 xcr0_features_bits
= xcr0
& X86_XSTATE_ALL_MASK
;
201 xcr0_features_bits
= 0;
206 switch (xcr0_features_bits
)
208 case X86_XSTATE_MPX_AVX512_MASK
:
209 case X86_XSTATE_AVX512_MASK
:
211 return tdesc_x32_avx512_linux
;
213 return tdesc_amd64_avx512_linux
;
214 case X86_XSTATE_MPX_MASK
:
216 return tdesc_x32_avx_linux
; /* No MPX on x32 using AVX. */
218 return tdesc_amd64_mpx_linux
;
219 case X86_XSTATE_AVX_MASK
:
221 return tdesc_x32_avx_linux
;
223 return tdesc_amd64_avx_linux
;
226 return tdesc_x32_linux
;
228 return tdesc_amd64_linux
;
234 switch (xcr0_features_bits
)
236 case X86_XSTATE_MPX_AVX512_MASK
:
237 case X86_XSTATE_AVX512_MASK
:
238 return tdesc_i386_avx512_linux
;
239 case X86_XSTATE_MPX_MASK
:
240 return tdesc_i386_mpx_linux
;
241 case X86_XSTATE_AVX_MASK
:
242 return tdesc_i386_avx_linux
;
244 return tdesc_i386_linux
;
248 gdb_assert_not_reached ("failed to return tdesc");
252 /* Enable branch tracing. */
254 static struct btrace_target_info
*
255 x86_linux_enable_btrace (struct target_ops
*self
, ptid_t ptid
,
256 const struct btrace_config
*conf
)
258 struct btrace_target_info
*tinfo
;
259 struct gdbarch
*gdbarch
;
262 tinfo
= linux_enable_btrace (ptid
, conf
);
265 error (_("Could not enable branch tracing for %s: %s."),
266 target_pid_to_str (ptid
), safe_strerror (errno
));
268 /* Fill in the size of a pointer in bits. */
269 if (tinfo
->ptr_bits
== 0)
271 gdbarch
= target_thread_architecture (ptid
);
272 tinfo
->ptr_bits
= gdbarch_ptr_bit (gdbarch
);
277 /* Disable branch tracing. */
280 x86_linux_disable_btrace (struct target_ops
*self
,
281 struct btrace_target_info
*tinfo
)
283 enum btrace_error errcode
= linux_disable_btrace (tinfo
);
285 if (errcode
!= BTRACE_ERR_NONE
)
286 error (_("Could not disable branch tracing."));
289 /* Teardown branch tracing. */
292 x86_linux_teardown_btrace (struct target_ops
*self
,
293 struct btrace_target_info
*tinfo
)
296 linux_disable_btrace (tinfo
);
299 static enum btrace_error
300 x86_linux_read_btrace (struct target_ops
*self
,
301 struct btrace_data
*data
,
302 struct btrace_target_info
*btinfo
,
303 enum btrace_read_type type
)
305 return linux_read_btrace (data
, btinfo
, type
);
308 /* See to_btrace_conf in target.h. */
310 static const struct btrace_config
*
311 x86_linux_btrace_conf (struct target_ops
*self
,
312 const struct btrace_target_info
*btinfo
)
314 return linux_btrace_conf (btinfo
);
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. */
324 x86_linux_get_thread_area (pid_t pid
, void *addr
, unsigned int *base_addr
)
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.
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
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];
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);
349 #ifndef PTRACE_GET_THREAD_AREA
350 #define PTRACE_GET_THREAD_AREA 25
353 if (ptrace (PTRACE_GET_THREAD_AREA
, pid
, addr
, &desc
) < 0)
356 *base_addr
= desc
[1];
361 /* Create an x86 GNU/Linux target. */
364 x86_linux_create_target (void)
366 /* Fill in the generic GNU/Linux methods. */
367 struct target_ops
*t
= linux_target ();
369 /* Initialize the debug register function vectors. */
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 *));
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
;
382 /* Add the description reader. */
383 t
->to_read_description
= x86_linux_read_description
;
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
;
391 t
->to_btrace_conf
= x86_linux_btrace_conf
;
396 /* Add an x86 GNU/Linux target. */
399 x86_linux_add_target (struct target_ops
*t
)
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
);
404 linux_nat_set_forget_process (t
, x86_forget_process
);
405 linux_nat_set_prepare_to_resume (t
, x86_linux_prepare_to_resume
);