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.
CC: Kay Sievers <k...@vrfy.org>
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
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
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 <jan.kis...@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()
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
--
2.1.4
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