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# kernel log buffer dump
5#
6# Copyright (c) Siemens AG, 2011, 2012
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
16from linux import utils
17
18
19class LxDmesg(gdb.Command):
20 """Print Linux kernel log buffer."""
21
22 def __init__(self):
23 super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA)
24
25 def invoke(self, arg, from_tty):
26 log_buf_addr = int(str(gdb.parse_and_eval("log_buf")).split()[0], 16)
27 log_first_idx = int(gdb.parse_and_eval("log_first_idx"))
28 log_next_idx = int(gdb.parse_and_eval("log_next_idx"))
29 log_buf_len = int(gdb.parse_and_eval("log_buf_len"))
30
31 inf = gdb.inferiors()[0]
32 start = log_buf_addr + log_first_idx
33 if log_first_idx < log_next_idx:
34 log_buf_2nd_half = -1
35 length = log_next_idx - log_first_idx
36 log_buf = utils.read_memoryview(inf, start, length).tobytes()
37 else:
38 log_buf_2nd_half = log_buf_len - log_first_idx
39 a = utils.read_memoryview(inf, start, log_buf_2nd_half)
40 b = utils.read_memoryview(inf, log_buf_addr, log_next_idx)
41 log_buf = a.tobytes() + b.tobytes()
42
43 pos = 0
44 while pos < log_buf.__len__():
45 length = utils.read_u16(log_buf[pos + 8:pos + 10])
46 if length == 0:
47 if log_buf_2nd_half == -1:
48 gdb.write("Corrupted log buffer!\n")
49 break
50 pos = log_buf_2nd_half
51 continue
52
53 text_len = utils.read_u16(log_buf[pos + 10:pos + 12])
54 text = log_buf[pos + 16:pos + 16 + text_len].decode()
55 time_stamp = utils.read_u64(log_buf[pos:pos + 8])
56
57 for line in text.splitlines():
58 gdb.write("[{time:12.6f}] {line}\n".format(
59 time=time_stamp / 1000000000.0,
60 line=line))
61
62 pos += length
63
64
65LxDmesg()