Commit 90cf83db authored by Stephen Boyd's avatar Stephen Boyd Committed by Linus Torvalds

scripts/gdb: add kernel config dumping command

lx-configdump <file> dumps the contents of the gzipped .config to a text
file when the config is included in the kernel with CONFIG_IKCONFIG.  By
default, the file written is called config.txt, but it can be any user
supplied filename as well.  If the kernel config is in a module
(configs.ko), then it can be loaded along with symbols for the module
loaded with 'lx-symbols' and then this command will still work.

Obviously if you have the whole vmlinux then this can also be achieved
with scripts/extract-ikconfig, but this gdb script can be useful to
confirm that the memory contents of the config in memory and the vmlinux
contents on disk match what is expected.

[swboyd@chromium.org: v2]
  Link: http://lkml.kernel.org/r/20190329220844.38234-3-swboyd@chromium.org
Link: http://lkml.kernel.org/r/20190325184522.260535-3-swboyd@chromium.orgSigned-off-by: default avatarStephen Boyd <swboyd@chromium.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jackie Liu <liuyun01@kylinos.cn>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent dfe4529e
# SPDX-License-Identifier: GPL-2.0
#
# Copyright 2019 Google LLC.
import gdb
import zlib
from linux import utils
class LxConfigDump(gdb.Command):
"""Output kernel config to the filename specified as the command
argument. Equivalent to 'zcat /proc/config.gz > config.txt' on
a running target"""
def __init__(self):
super(LxConfigDump, self).__init__("lx-configdump", gdb.COMMAND_DATA,
gdb.COMPLETE_FILENAME)
def invoke(self, arg, from_tty):
if len(arg) == 0:
filename = "config.txt"
else:
filename = arg
try:
py_config_ptr = gdb.parse_and_eval("kernel_config_data + 8")
py_config_size = gdb.parse_and_eval(
"sizeof(kernel_config_data) - 1 - 8 * 2")
except gdb.error as e:
raise gdb.GdbError("Can't find config, enable CONFIG_IKCONFIG?")
inf = gdb.inferiors()[0]
zconfig_buf = utils.read_memoryview(inf, py_config_ptr,
py_config_size).tobytes()
config_buf = zlib.decompress(zconfig_buf, 16)
with open(filename, 'wb') as f:
f.write(config_buf)
gdb.write("Dumped config to " + filename + "\n")
LxConfigDump()
......@@ -27,6 +27,7 @@ else:
import linux.modules
import linux.dmesg
import linux.tasks
import linux.config
import linux.cpus
import linux.lists
import linux.proc
......
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