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
126target_arch = None
127
128
129def is_target_arch(arch):
130 if hasattr(gdb.Frame, 'architecture'):
131 return arch in gdb.newest_frame().architecture().name()
132 else:
133 global target_arch
134 if target_arch is None:
135 target_arch = gdb.execute("show architecture", to_string=True)
136 return arch in target_arch
137
138
139GDBSERVER_QEMU = 0
140GDBSERVER_KGDB = 1
141gdbserver_type = None
142
143
144def get_gdbserver_type():
145 def exit_handler(event):
146 global gdbserver_type
147 gdbserver_type = None
148 gdb.events.exited.disconnect(exit_handler)
149
150 def probe_qemu():
151 try:
152 return gdb.execute("monitor info version", to_string=True) != ""
153 except gdb.error:
154 return False
155
156 def probe_kgdb():
157 try:
158 thread_info = gdb.execute("info thread 2", to_string=True)
159 return "shadowCPU0" in thread_info
160 except gdb.error:
161 return False
162
163 global gdbserver_type
164 if gdbserver_type is None:
165 if probe_qemu():
166 gdbserver_type = GDBSERVER_QEMU
167 elif probe_kgdb():
168 gdbserver_type = GDBSERVER_KGDB
169 if gdbserver_type is not None and hasattr(gdb, 'events'):
170 gdb.events.exited.connect(exit_handler)
171 return gdbserver_type
172
173
174def gdb_eval_or_none(expresssion):
175 try:
176 return gdb.parse_and_eval(expresssion)
177 except gdb.error:
178 return None
179
180
181def dentry_name(d):
182 parent = d['d_parent']
183 if parent == d or parent == 0:
184 return ""
185 p = dentry_name(d['d_parent']) + "/"
186 return p + d['d_iname'].string()