1 /* Native-dependent code for FreeBSD/i386.
3 Copyright (C) 2001-2017 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/>. */
25 #include <sys/types.h>
26 #include <sys/ptrace.h>
27 #include <sys/sysctl.h>
31 #include "i386-tdep.h"
33 #include "x86-bsd-nat.h"
34 #include "i386-bsd-nat.h"
36 /* Resume execution of the inferior process. If STEP is nonzero,
37 single-step it. If SIGNAL is nonzero, give it that signal. */
40 i386fbsd_resume (struct target_ops
*ops
,
41 ptid_t ptid
, int step
, enum gdb_signal signal
)
43 pid_t pid
= ptid_get_pid (ptid
);
44 int request
= PT_STEP
;
47 /* Resume all threads. This only gets used in the non-threaded
48 case, where "resume all threads" and "resume inferior_ptid" are
50 pid
= ptid_get_pid (inferior_ptid
);
54 struct regcache
*regcache
= get_current_regcache ();
57 /* Workaround for a bug in FreeBSD. Make sure that the trace
58 flag is off when doing a continue. There is a code path
59 through the kernel which leaves the flag set when it should
60 have been cleared. If a process has a signal pending (such
61 as SIGALRM) and we do a PT_STEP, the process never really has
62 a chance to run because the kernel needs to notify the
63 debugger that a signal is being sent. Therefore, the process
64 never goes through the kernel's trap() function which would
67 regcache_cooked_read_unsigned (regcache
, I386_EFLAGS_REGNUM
,
70 regcache_cooked_write_unsigned (regcache
, I386_EFLAGS_REGNUM
,
73 request
= PT_CONTINUE
;
76 /* An addres of (caddr_t) 1 tells ptrace to continue from where it
77 was. (If GDB wanted it to start some other way, we have already
78 written a new PC value to the child.) */
79 if (ptrace (request
, pid
, (caddr_t
) 1,
80 gdb_signal_to_host (signal
)) == -1)
81 perror_with_name (("ptrace"));
85 /* Support for debugging kernel virtual memory images. */
87 #include <machine/pcb.h>
92 i386fbsd_supply_pcb (struct regcache
*regcache
, struct pcb
*pcb
)
94 /* The following is true for FreeBSD 4.7:
96 The pcb contains %eip, %ebx, %esp, %ebp, %esi, %edi and %gs.
97 This accounts for all callee-saved registers specified by the
98 psABI and then some. Here %esp contains the stack pointer at the
99 point just after the call to cpu_switch(). From this information
100 we reconstruct the register state as it would look when we just
101 returned from cpu_switch(). */
103 /* The stack pointer shouldn't be zero. */
104 if (pcb
->pcb_esp
== 0)
108 regcache_raw_supply (regcache
, I386_EDI_REGNUM
, &pcb
->pcb_edi
);
109 regcache_raw_supply (regcache
, I386_ESI_REGNUM
, &pcb
->pcb_esi
);
110 regcache_raw_supply (regcache
, I386_EBP_REGNUM
, &pcb
->pcb_ebp
);
111 regcache_raw_supply (regcache
, I386_ESP_REGNUM
, &pcb
->pcb_esp
);
112 regcache_raw_supply (regcache
, I386_EBX_REGNUM
, &pcb
->pcb_ebx
);
113 regcache_raw_supply (regcache
, I386_EIP_REGNUM
, &pcb
->pcb_eip
);
114 regcache_raw_supply (regcache
, I386_GS_REGNUM
, &pcb
->pcb_gs
);
120 #ifdef PT_GETXSTATE_INFO
121 /* Implement the to_read_description method. */
123 static const struct target_desc
*
124 i386fbsd_read_description (struct target_ops
*ops
)
126 static int xsave_probed
;
127 static uint64_t xcr0
;
131 struct ptrace_xstate_info info
;
133 if (ptrace (PT_GETXSTATE_INFO
, ptid_get_pid (inferior_ptid
),
134 (PTRACE_TYPE_ARG3
) &info
, sizeof (info
)) == 0)
136 x86bsd_xsave_len
= info
.xsave_len
;
137 xcr0
= info
.xsave_mask
;
142 if (x86bsd_xsave_len
!= 0)
144 return i386_target_description (xcr0
);
151 /* Prevent warning from -Wmissing-prototypes. */
152 void _initialize_i386fbsd_nat (void);
155 _initialize_i386fbsd_nat (void)
157 struct target_ops
*t
;
159 /* Add some extra features to the common *BSD/i386 target. */
160 t
= i386bsd_target ();
162 #ifdef PT_GETXSTATE_INFO
163 t
->to_read_description
= i386fbsd_read_description
;
166 t
->to_resume
= i386fbsd_resume
;
167 fbsd_nat_add_target (t
);
169 /* Support debugging kernel virtual memory images. */
170 bsd_kvm_add_target (i386fbsd_supply_pcb
);
172 #ifdef KERN_PROC_SIGTRAMP
173 /* Normally signal frames are detected via i386fbsd_sigtramp_p.
174 However, FreeBSD 9.2 through 10.1 do not include the page holding
175 the signal code in core dumps. These releases do provide a
176 kern.proc.sigtramp.<pid> sysctl that returns the location of the
177 signal trampoline for a running process. We fetch the location
178 of the current (gdb) process and use this to identify signal
179 frames in core dumps from these releases. */
182 struct kinfo_sigtramp kst
;
187 mib
[2] = KERN_PROC_SIGTRAMP
;
190 if (sysctl (mib
, 4, &kst
, &len
, NULL
, 0) == 0)
192 i386fbsd_sigtramp_start_addr
= (uintptr_t) kst
.ksigtramp_start
;
193 i386fbsd_sigtramp_end_addr
= (uintptr_t) kst
.ksigtramp_end
;