1 /* Copyright (C) 2011-2022 Free Software Foundation, Inc.
3 This file is part of GDB.
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18 #ifndef NAT_LINUX_PTRACE_H
19 #define NAT_LINUX_PTRACE_H
23 #include "nat/gdb_ptrace.h"
24 #include "gdbsupport/gdb_wait.h"
27 #if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
28 /* PTRACE_TEXT_ADDR and friends. */
29 #include <asm/ptrace.h>
34 #if !defined(PTRACE_TYPE_ARG3)
35 #define PTRACE_TYPE_ARG3 void *
38 #if !defined(PTRACE_TYPE_ARG4)
39 #define PTRACE_TYPE_ARG4 void *
42 #ifndef PTRACE_GETSIGINFO
43 # define PTRACE_GETSIGINFO 0x4202
44 # define PTRACE_SETSIGINFO 0x4203
45 #endif /* PTRACE_GETSIGINF */
47 #ifndef PTRACE_GETREGSET
48 #define PTRACE_GETREGSET 0x4204
51 #ifndef PTRACE_SETREGSET
52 #define PTRACE_SETREGSET 0x4205
55 /* If the system headers did not provide the constants, hard-code the normal
57 #ifndef PTRACE_EVENT_FORK
59 #define PTRACE_SETOPTIONS 0x4200
60 #define PTRACE_GETEVENTMSG 0x4201
62 /* options set using PTRACE_SETOPTIONS */
63 #define PTRACE_O_TRACESYSGOOD 0x00000001
64 #define PTRACE_O_TRACEFORK 0x00000002
65 #define PTRACE_O_TRACEVFORK 0x00000004
66 #define PTRACE_O_TRACECLONE 0x00000008
67 #define PTRACE_O_TRACEEXEC 0x00000010
68 #define PTRACE_O_TRACEVFORKDONE 0x00000020
69 #define PTRACE_O_TRACEEXIT 0x00000040
71 /* Wait extended result codes for the above trace options. */
72 #define PTRACE_EVENT_FORK 1
73 #define PTRACE_EVENT_VFORK 2
74 #define PTRACE_EVENT_CLONE 3
75 #define PTRACE_EVENT_EXEC 4
76 #define PTRACE_EVENT_VFORK_DONE 5
77 #define PTRACE_EVENT_EXIT 6
79 #endif /* PTRACE_EVENT_FORK */
81 #ifndef PTRACE_O_EXITKILL
82 /* Only defined in Linux Kernel 3.8 or later. */
83 #define PTRACE_O_EXITKILL 0x00100000
86 #if (defined __bfin__ || defined __frv__ || defined __sh__) \
87 && !defined PTRACE_GETFDPIC
88 #define PTRACE_GETFDPIC 31
89 #define PTRACE_GETFDPIC_EXEC 0
90 #define PTRACE_GETFDPIC_INTERP 1
93 /* We can't always assume that this flag is available, but all systems
94 with the ptrace event handlers also have __WALL, so it's safe to use
97 #define __WALL 0x40000000 /* Wait for any child. */
100 /* True if whether a breakpoint/watchpoint triggered can be determined
101 from the si_code of SIGTRAP's siginfo_t (TRAP_BRKPT/TRAP_HWBKPT).
102 That is, if the kernel can tell us whether the thread executed a
103 software breakpoint, we trust it. The kernel will be determining
104 that from the hardware (e.g., from which exception was raised in
105 the CPU). Relying on whether a breakpoint is planted in memory at
106 the time the SIGTRAP is processed to determine whether the thread
107 stopped for a software breakpoint can be too late. E.g., the
108 breakpoint could have been removed since. Or the thread could have
109 stepped an instruction the size of a breakpoint instruction, and
110 before the stop is processed a breakpoint is inserted at its
111 address. Getting these wrong is disastrous on decr_pc_after_break
112 architectures. The moribund location mechanism helps with that
113 somewhat but it is an heuristic, and can well fail. Getting that
114 information out of the kernel and ultimately out of the CPU is the
115 way to go. That said, some architecture may get the si_code wrong,
116 and as such we're leaving fallback code in place. We'll remove
117 this after a while if no problem is reported. */
118 #define USE_SIGTRAP_SIGINFO 1
120 /* The x86 kernel gets some of the si_code values backwards, like
124 |------------------------------------------+-------------|
125 | software breakpoints (int3) | SI_KERNEL |
126 | single-steps | TRAP_TRACE |
127 | single-stepping a syscall | TRAP_BRKPT |
128 | user sent SIGTRAP | 0 |
129 | exec SIGTRAP (when no PTRACE_EVENT_EXEC) | 0 |
130 | hardware breakpoints/watchpoints | TRAP_HWBKPT |
132 That is, it reports SI_KERNEL for software breakpoints (and only
133 for those), and TRAP_BRKPT for single-stepping a syscall... If the
134 kernel is ever fixed, we'll just have to detect it like we detect
135 optional ptrace features: by forking and debugging ourselves,
136 running to a breakpoint and checking what comes out of
139 The ppc kernel does use TRAP_BRKPT for software breakpoints
140 in PowerPC code, but it uses SI_KERNEL for software breakpoints
141 in SPU code on a Cell/B.E. However, SI_KERNEL is never seen
142 on a SIGTRAP for any other reason.
144 The MIPS kernel up until 4.5 used SI_KERNEL for all kernel
145 generated traps. Since:
147 - MIPS doesn't do hardware single-step.
148 - We don't need to care about exec SIGTRAPs --- we assume
149 PTRACE_EVENT_EXEC is available.
150 - The MIPS kernel doesn't support hardware breakpoints.
152 on MIPS, all we need to care about is distinguishing between
153 software breakpoints and hardware watchpoints, which can be done by
154 peeking the debug registers.
156 Beginning with Linux 4.6, the MIPS port reports proper TRAP_BRKPT and
157 TRAP_HWBKPT codes, so we also match them.
159 The generic Linux target code should use GDB_ARCH_IS_TRAP_* instead
160 of TRAP_* to abstract out these peculiarities. */
161 #if defined __i386__ || defined __x86_64__
162 # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL)
163 # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
164 #elif defined __powerpc__
165 # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL || (X) == TRAP_BRKPT)
166 # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
167 #elif defined __mips__
168 # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL || (X) == TRAP_BRKPT)
169 # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == SI_KERNEL || (X) == TRAP_HWBKPT)
171 # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == TRAP_BRKPT)
172 # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
176 # define TRAP_HWBKPT 4
179 extern std::string
linux_ptrace_attach_fail_reason (pid_t pid
);
181 /* Find all possible reasons we could have failed to attach to PTID
182 and return them as a string. ERR is the error PTRACE_ATTACH failed
184 extern std::string
linux_ptrace_attach_fail_reason_string (ptid_t ptid
, int err
);
186 extern void linux_ptrace_init_warnings (void);
187 extern void linux_check_ptrace_features (void);
188 extern void linux_enable_event_reporting (pid_t pid
, int attached
);
189 extern void linux_disable_event_reporting (pid_t pid
);
190 extern int linux_supports_tracefork (void);
191 extern int linux_supports_traceexec (void);
192 extern int linux_supports_traceclone (void);
193 extern int linux_supports_tracevforkdone (void);
194 extern int linux_supports_tracesysgood (void);
195 extern int linux_ptrace_get_extended_event (int wstat
);
196 extern int linux_is_extended_waitstatus (int wstat
);
197 extern int linux_wstatus_maybe_breakpoint (int wstat
);
199 #endif /* NAT_LINUX_PTRACE_H */