From ae7dbaad23f0346dc4e2476be63a9a5a376ee472 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Tue, 17 Feb 2015 13:47:04 -0800 Subject: 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 Cc: Kay Sievers Cc: Thomas Gleixner Cc: Jason Wessel Cc: Andi Kleen Cc: Ben Widawsky Cc: Borislav Petkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/gdb/linux/dmesg.py | 64 ++++++++++++++++++++++++++++++++++++++++++++++ scripts/gdb/vmlinux-gdb.py | 1 + 2 files changed, 65 insertions(+) create mode 100644 scripts/gdb/linux/dmesg.py (limited to 'scripts/gdb') diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py new file mode 100644 index 0000000..7650f24 --- /dev/null +++ b/scripts/gdb/linux/dmesg.py @@ -0,0 +1,64 @@ +# +# gdb helper commands and functions for Linux kernel debugging +# +# kernel log buffer dump +# +# Copyright (c) Siemens AG, 2011, 2012 +# +# Authors: +# Jan Kiszka +# +# 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() diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py index cf2e716..fa66d23 100644 --- a/scripts/gdb/vmlinux-gdb.py +++ b/scripts/gdb/vmlinux-gdb.py @@ -25,3 +25,4 @@ else: import linux.utils import linux.symbols import linux.modules + import linux.dmesg -- cgit v1.1