Commit ae7dbaad authored by Jan Kiszka's avatar Jan Kiszka Committed by Linus Torvalds

scripts/gdb: add lx-dmesg command

This pokes into the log buffer of the debugged kernel, dumping it to the
gdb console.  Helping in case the target should or can no longer execute
dmesg itself.
Signed-off-by: Jan Kiszka's avatarJan Kiszka <jan.kiszka@siemens.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 78e87817
#
# gdb helper commands and functions for Linux kernel debugging
#
# kernel log buffer dump
#
# Copyright (c) Siemens AG, 2011, 2012
#
# Authors:
# Jan Kiszka <jan.kiszka@siemens.com>
#
# This work is licensed under the terms of the GNU GPL version 2.
#
import gdb
import string
from linux import utils
class LxDmesg(gdb.Command):
"""Print Linux kernel log buffer."""
def __init__(self):
super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA)
def invoke(self, arg, from_tty):
log_buf_addr = int(str(gdb.parse_and_eval("log_buf")).split()[0], 16)
log_first_idx = int(gdb.parse_and_eval("log_first_idx"))
log_next_idx = int(gdb.parse_and_eval("log_next_idx"))
log_buf_len = int(gdb.parse_and_eval("log_buf_len"))
inf = gdb.inferiors()[0]
start = log_buf_addr + log_first_idx
if log_first_idx < log_next_idx:
log_buf_2nd_half = -1
length = log_next_idx - log_first_idx
log_buf = inf.read_memory(start, length)
else:
log_buf_2nd_half = log_buf_len - log_first_idx
log_buf = inf.read_memory(start, log_buf_2nd_half) + \
inf.read_memory(log_buf_addr, log_next_idx)
pos = 0
while pos < log_buf.__len__():
length = utils.read_u16(log_buf[pos + 8:pos + 10])
if length == 0:
if log_buf_2nd_half == -1:
gdb.write("Corrupted log buffer!\n")
break
pos = log_buf_2nd_half
continue
text_len = utils.read_u16(log_buf[pos + 10:pos + 12])
time_stamp = utils.read_u64(log_buf[pos:pos + 8])
for line in log_buf[pos + 16:pos + 16 + text_len].splitlines():
gdb.write("[{time:12.6f}] {line}\n".format(
time=time_stamp / 1000000000.0,
line=line))
pos += length
LxDmesg()
......@@ -25,3 +25,4 @@ else:
import linux.utils
import linux.symbols
import linux.modules
import linux.dmesg
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