Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#
2# gdb helper commands and functions for Linux kernel debugging
3#
4# common utilities
5#
6# Copyright (c) Siemens AG, 2011-2013
7#
8# Authors:
9# Jan Kiszka <jan.kiszka@siemens.com>
10#
11# This work is licensed under the terms of the GNU GPL version 2.
12#
13
14import gdb
15
16
17class CachedType:
18 def __init__(self, name):
19 self._type = None
20 self._name = name
21
22 def _new_objfile_handler(self, event):
23 self._type = None
24 gdb.events.new_objfile.disconnect(self._new_objfile_handler)
25
26 def get_type(self):
27 if self._type is None:
28 self._type = gdb.lookup_type(self._name)
29 if self._type is None:
30 raise gdb.GdbError(
31 "cannot resolve type '{0}'".format(self._name))
32 if hasattr(gdb, 'events') and hasattr(gdb.events, 'new_objfile'):
33 gdb.events.new_objfile.connect(self._new_objfile_handler)
34 return self._type
35
36
37long_type = CachedType("long")
38
39
40def get_long_type():
41 global long_type
42 return long_type.get_type()
43
44
45def offset_of(typeobj, field):
46 element = gdb.Value(0).cast(typeobj)
47 return int(str(element[field].address).split()[0], 16)
48
49
50def container_of(ptr, typeobj, member):
51 return (ptr.cast(get_long_type()) -
52 offset_of(typeobj, member)).cast(typeobj)
53
54
55class ContainerOf(gdb.Function):
56 """Return pointer to containing data structure.
57
58$container_of(PTR, "TYPE", "ELEMENT"): Given PTR, return a pointer to the
59data structure of the type TYPE in which PTR is the address of ELEMENT.
60Note that TYPE and ELEMENT have to be quoted as strings."""
61
62 def __init__(self):
63 super(ContainerOf, self).__init__("container_of")
64
65 def invoke(self, ptr, typename, elementname):
66 return container_of(ptr, gdb.lookup_type(typename.string()).pointer(),
67 elementname.string())
68
69
70ContainerOf()
71
72
73BIG_ENDIAN = 0
74LITTLE_ENDIAN = 1
75target_endianness = None
76
77
78def get_target_endianness():
79 global target_endianness
80 if target_endianness is None:
81 endian = gdb.execute("show endian", to_string=True)
82 if "little endian" in endian:
83 target_endianness = LITTLE_ENDIAN
84 elif "big endian" in endian:
85 target_endianness = BIG_ENDIAN
86 else:
87 raise gdb.GdbError("unknown endianness '{0}'".format(str(endian)))
88 return target_endianness
89
90
91def read_memoryview(inf, start, length):
92 return memoryview(inf.read_memory(start, length))
93
94
95def read_u16(buffer, offset):
96 buffer_val = buffer[offset:offset + 2]
97 value = [0, 0]
98
99 if type(buffer_val[0]) is str:
100 value[0] = ord(buffer_val[0])
101 value[1] = ord(buffer_val[1])
102 else:
103 value[0] = buffer_val[0]
104 value[1] = buffer_val[1]
105
106 if get_target_endianness() == LITTLE_ENDIAN:
107 return value[0] + (value[1] << 8)
108 else:
109 return value[1] + (value[0] << 8)
110
111
112def read_u32(buffer, offset):
113 if get_target_endianness() == LITTLE_ENDIAN:
114 return read_u16(buffer, offset) + (read_u16(buffer, offset + 2) << 16)
115 else:
116 return read_u16(buffer, offset + 2) + (read_u16(buffer, offset) << 16)
117
118
119def read_u64(buffer, offset):
120 if get_target_endianness() == LITTLE_ENDIAN:
121 return read_u32(buffer, offset) + (read_u32(buffer, offset + 4) << 32)
122 else:
123 return read_u32(buffer, offset + 4) + (read_u32(buffer, offset) << 32)
124
125
126def read_ulong(buffer, offset):
127 if get_long_type().sizeof == 8:
128 return read_u64(buffer, offset)
129 else:
130 return read_u32(buffer, offset)
131
132
133target_arch = None
134
135
136def is_target_arch(arch):
137 if hasattr(gdb.Frame, 'architecture'):
138 return arch in gdb.newest_frame().architecture().name()
139 else:
140 global target_arch
141 if target_arch is None:
142 target_arch = gdb.execute("show architecture", to_string=True)
143 return arch in target_arch
144
145
146GDBSERVER_QEMU = 0
147GDBSERVER_KGDB = 1
148gdbserver_type = None
149
150
151def get_gdbserver_type():
152 def exit_handler(event):
153 global gdbserver_type
154 gdbserver_type = None
155 gdb.events.exited.disconnect(exit_handler)
156
157 def probe_qemu():
158 try:
159 return gdb.execute("monitor info version", to_string=True) != ""
160 except gdb.error:
161 return False
162
163 def probe_kgdb():
164 try:
165 thread_info = gdb.execute("info thread 2", to_string=True)
166 return "shadowCPU0" in thread_info
167 except gdb.error:
168 return False
169
170 global gdbserver_type
171 if gdbserver_type is None:
172 if probe_qemu():
173 gdbserver_type = GDBSERVER_QEMU
174 elif probe_kgdb():
175 gdbserver_type = GDBSERVER_KGDB
176 if gdbserver_type is not None and hasattr(gdb, 'events'):
177 gdb.events.exited.connect(exit_handler)
178 return gdbserver_type
179
180
181def gdb_eval_or_none(expresssion):
182 try:
183 return gdb.parse_and_eval(expresssion)
184 except gdb.error:
185 return None
186
187
188def dentry_name(d):
189 parent = d['d_parent']
190 if parent == d or parent == 0:
191 return ""
192 p = dentry_name(d['d_parent']) + "/"
193 return p + d['d_iname'].string()