Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1# SPDX-License-Identifier: GPL-2.0
2#
3# gdb helper commands and functions for Linux kernel debugging
4#
5# Kernel proc information reader
6#
7# Copyright (c) 2016 Linaro Ltd
8#
9# Authors:
10# Kieran Bingham <kieran.bingham@linaro.org>
11#
12# This work is licensed under the terms of the GNU GPL version 2.
13#
14
15import gdb
16from linux import constants
17from linux import utils
18from linux import tasks
19from linux import lists
20from linux import vfs
21from struct import *
22
23
24class LxCmdLine(gdb.Command):
25 """ Report the Linux Commandline used in the current kernel.
26 Equivalent to cat /proc/cmdline on a running target"""
27
28 def __init__(self):
29 super(LxCmdLine, self).__init__("lx-cmdline", gdb.COMMAND_DATA)
30
31 def invoke(self, arg, from_tty):
32 gdb.write(gdb.parse_and_eval("saved_command_line").string() + "\n")
33
34
35LxCmdLine()
36
37
38class LxVersion(gdb.Command):
39 """ Report the Linux Version of the current kernel.
40 Equivalent to cat /proc/version on a running target"""
41
42 def __init__(self):
43 super(LxVersion, self).__init__("lx-version", gdb.COMMAND_DATA)
44
45 def invoke(self, arg, from_tty):
46 # linux_banner should contain a newline
47 gdb.write(gdb.parse_and_eval("(char *)linux_banner").string())
48
49
50LxVersion()
51
52
53# Resource Structure Printers
54# /proc/iomem
55# /proc/ioports
56
57def get_resources(resource, depth):
58 while resource:
59 yield resource, depth
60
61 child = resource['child']
62 if child:
63 for res, deep in get_resources(child, depth + 1):
64 yield res, deep
65
66 resource = resource['sibling']
67
68
69def show_lx_resources(resource_str):
70 resource = gdb.parse_and_eval(resource_str)
71 width = 4 if resource['end'] < 0x10000 else 8
72 # Iterate straight to the first child
73 for res, depth in get_resources(resource['child'], 0):
74 start = int(res['start'])
75 end = int(res['end'])
76 gdb.write(" " * depth * 2 +
77 "{0:0{1}x}-".format(start, width) +
78 "{0:0{1}x} : ".format(end, width) +
79 res['name'].string() + "\n")
80
81
82class LxIOMem(gdb.Command):
83 """Identify the IO memory resource locations defined by the kernel
84
85Equivalent to cat /proc/iomem on a running target"""
86
87 def __init__(self):
88 super(LxIOMem, self).__init__("lx-iomem", gdb.COMMAND_DATA)
89
90 def invoke(self, arg, from_tty):
91 return show_lx_resources("iomem_resource")
92
93
94LxIOMem()
95
96
97class LxIOPorts(gdb.Command):
98 """Identify the IO port resource locations defined by the kernel
99
100Equivalent to cat /proc/ioports on a running target"""
101
102 def __init__(self):
103 super(LxIOPorts, self).__init__("lx-ioports", gdb.COMMAND_DATA)
104
105 def invoke(self, arg, from_tty):
106 return show_lx_resources("ioport_resource")
107
108
109LxIOPorts()
110
111
112# Mount namespace viewer
113# /proc/mounts
114
115def info_opts(lst, opt):
116 opts = ""
117 for key, string in lst.items():
118 if opt & key:
119 opts += string
120 return opts
121
122
123FS_INFO = {constants.LX_SB_SYNCHRONOUS: ",sync",
124 constants.LX_SB_MANDLOCK: ",mand",
125 constants.LX_SB_DIRSYNC: ",dirsync",
126 constants.LX_SB_NOATIME: ",noatime",
127 constants.LX_SB_NODIRATIME: ",nodiratime"}
128
129MNT_INFO = {constants.LX_MNT_NOSUID: ",nosuid",
130 constants.LX_MNT_NODEV: ",nodev",
131 constants.LX_MNT_NOEXEC: ",noexec",
132 constants.LX_MNT_NOATIME: ",noatime",
133 constants.LX_MNT_NODIRATIME: ",nodiratime",
134 constants.LX_MNT_RELATIME: ",relatime"}
135
136mount_type = utils.CachedType("struct mount")
137mount_ptr_type = mount_type.get_type().pointer()
138
139
140class LxMounts(gdb.Command):
141 """Report the VFS mounts of the current process namespace.
142
143Equivalent to cat /proc/mounts on a running target
144An integer value can be supplied to display the mount
145values of that process namespace"""
146
147 def __init__(self):
148 super(LxMounts, self).__init__("lx-mounts", gdb.COMMAND_DATA)
149
150 # Equivalent to proc_namespace.c:show_vfsmnt
151 # However, that has the ability to call into s_op functions
152 # whereas we cannot and must make do with the information we can obtain.
153 def invoke(self, arg, from_tty):
154 argv = gdb.string_to_argv(arg)
155 if len(argv) >= 1:
156 try:
157 pid = int(argv[0])
158 except gdb.error:
159 raise gdb.GdbError("Provide a PID as integer value")
160 else:
161 pid = 1
162
163 task = tasks.get_task_by_pid(pid)
164 if not task:
165 raise gdb.GdbError("Couldn't find a process with PID {}"
166 .format(pid))
167
168 namespace = task['nsproxy']['mnt_ns']
169 if not namespace:
170 raise gdb.GdbError("No namespace for current process")
171
172 gdb.write("{:^18} {:^15} {:>9} {} {} options\n".format(
173 "mount", "super_block", "devname", "pathname", "fstype"))
174
175 for mnt in lists.list_for_each_entry(namespace['list'],
176 mount_ptr_type, "mnt_list"):
177 devname = mnt['mnt_devname'].string()
178 devname = devname if devname else "none"
179
180 pathname = ""
181 parent = mnt
182 while True:
183 mntpoint = parent['mnt_mountpoint']
184 pathname = vfs.dentry_name(mntpoint) + pathname
185 if (parent == parent['mnt_parent']):
186 break
187 parent = parent['mnt_parent']
188
189 if (pathname == ""):
190 pathname = "/"
191
192 superblock = mnt['mnt']['mnt_sb']
193 fstype = superblock['s_type']['name'].string()
194 s_flags = int(superblock['s_flags'])
195 m_flags = int(mnt['mnt']['mnt_flags'])
196 rd = "ro" if (s_flags & constants.LX_SB_RDONLY) else "rw"
197
198 gdb.write("{} {} {} {} {} {}{}{} 0 0\n".format(
199 mnt.format_string(), superblock.format_string(), devname,
200 pathname, fstype, rd, info_opts(FS_INFO, s_flags),
201 info_opts(MNT_INFO, m_flags)))
202
203
204LxMounts()
205
206
207class LxFdtDump(gdb.Command):
208 """Output Flattened Device Tree header and dump FDT blob to the filename
209 specified as the command argument. Equivalent to
210 'cat /proc/fdt > fdtdump.dtb' on a running target"""
211
212 def __init__(self):
213 super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA,
214 gdb.COMPLETE_FILENAME)
215
216 def fdthdr_to_cpu(self, fdt_header):
217
218 fdt_header_be = ">IIIIIII"
219 fdt_header_le = "<IIIIIII"
220
221 if utils.get_target_endianness() == 1:
222 output_fmt = fdt_header_le
223 else:
224 output_fmt = fdt_header_be
225
226 return unpack(output_fmt, pack(fdt_header_be,
227 fdt_header['magic'],
228 fdt_header['totalsize'],
229 fdt_header['off_dt_struct'],
230 fdt_header['off_dt_strings'],
231 fdt_header['off_mem_rsvmap'],
232 fdt_header['version'],
233 fdt_header['last_comp_version']))
234
235 def invoke(self, arg, from_tty):
236
237 if not constants.LX_CONFIG_OF:
238 raise gdb.GdbError("Kernel not compiled with CONFIG_OF\n")
239
240 if len(arg) == 0:
241 filename = "fdtdump.dtb"
242 else:
243 filename = arg
244
245 py_fdt_header_ptr = gdb.parse_and_eval(
246 "(const struct fdt_header *) initial_boot_params")
247 py_fdt_header = py_fdt_header_ptr.dereference()
248
249 fdt_header = self.fdthdr_to_cpu(py_fdt_header)
250
251 if fdt_header[0] != constants.LX_OF_DT_HEADER:
252 raise gdb.GdbError("No flattened device tree magic found\n")
253
254 gdb.write("fdt_magic: 0x{:02X}\n".format(fdt_header[0]))
255 gdb.write("fdt_totalsize: 0x{:02X}\n".format(fdt_header[1]))
256 gdb.write("off_dt_struct: 0x{:02X}\n".format(fdt_header[2]))
257 gdb.write("off_dt_strings: 0x{:02X}\n".format(fdt_header[3]))
258 gdb.write("off_mem_rsvmap: 0x{:02X}\n".format(fdt_header[4]))
259 gdb.write("version: {}\n".format(fdt_header[5]))
260 gdb.write("last_comp_version: {}\n".format(fdt_header[6]))
261
262 inf = gdb.inferiors()[0]
263 fdt_buf = utils.read_memoryview(inf, py_fdt_header_ptr,
264 fdt_header[1]).tobytes()
265
266 try:
267 f = open(filename, 'wb')
268 except gdb.error:
269 raise gdb.GdbError("Could not open file to dump fdt")
270
271 f.write(fdt_buf)
272 f.close()
273
274 gdb.write("Dumped fdt blob to " + filename + "\n")
275
276
277LxFdtDump()