forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
154 lines
5.8 KiB
154 lines
5.8 KiB
# |
|
# gdb helper commands and functions for Linux kernel debugging |
|
# |
|
# kernel log buffer dump |
|
# |
|
# Copyright (c) Siemens AG, 2011, 2012 |
|
# |
|
# Authors: |
|
# Jan Kiszka <[email protected]> |
|
# |
|
# This work is licensed under the terms of the GNU GPL version 2. |
|
# |
|
|
|
import gdb |
|
import sys |
|
|
|
from linux import utils |
|
|
|
printk_info_type = utils.CachedType("struct printk_info") |
|
prb_data_blk_lpos_type = utils.CachedType("struct prb_data_blk_lpos") |
|
prb_desc_type = utils.CachedType("struct prb_desc") |
|
prb_desc_ring_type = utils.CachedType("struct prb_desc_ring") |
|
prb_data_ring_type = utils.CachedType("struct prb_data_ring") |
|
printk_ringbuffer_type = utils.CachedType("struct printk_ringbuffer") |
|
atomic_long_type = utils.CachedType("atomic_long_t") |
|
|
|
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): |
|
inf = gdb.inferiors()[0] |
|
|
|
# read in prb structure |
|
prb_addr = int(str(gdb.parse_and_eval("(void *)'printk.c'::prb")).split()[0], 16) |
|
sz = printk_ringbuffer_type.get_type().sizeof |
|
prb = utils.read_memoryview(inf, prb_addr, sz).tobytes() |
|
|
|
# read in descriptor ring structure |
|
off = printk_ringbuffer_type.get_type()['desc_ring'].bitpos // 8 |
|
addr = prb_addr + off |
|
sz = prb_desc_ring_type.get_type().sizeof |
|
desc_ring = utils.read_memoryview(inf, addr, sz).tobytes() |
|
|
|
# read in descriptor array |
|
off = prb_desc_ring_type.get_type()['count_bits'].bitpos // 8 |
|
desc_ring_count = 1 << utils.read_u32(desc_ring, off) |
|
desc_sz = prb_desc_type.get_type().sizeof |
|
off = prb_desc_ring_type.get_type()['descs'].bitpos // 8 |
|
addr = utils.read_ulong(desc_ring, off) |
|
descs = utils.read_memoryview(inf, addr, desc_sz * desc_ring_count).tobytes() |
|
|
|
# read in info array |
|
info_sz = printk_info_type.get_type().sizeof |
|
off = prb_desc_ring_type.get_type()['infos'].bitpos // 8 |
|
addr = utils.read_ulong(desc_ring, off) |
|
infos = utils.read_memoryview(inf, addr, info_sz * desc_ring_count).tobytes() |
|
|
|
# read in text data ring structure |
|
off = printk_ringbuffer_type.get_type()['text_data_ring'].bitpos // 8 |
|
addr = prb_addr + off |
|
sz = prb_data_ring_type.get_type().sizeof |
|
text_data_ring = utils.read_memoryview(inf, addr, sz).tobytes() |
|
|
|
# read in text data |
|
off = prb_data_ring_type.get_type()['size_bits'].bitpos // 8 |
|
text_data_sz = 1 << utils.read_u32(text_data_ring, off) |
|
off = prb_data_ring_type.get_type()['data'].bitpos // 8 |
|
addr = utils.read_ulong(text_data_ring, off) |
|
text_data = utils.read_memoryview(inf, addr, text_data_sz).tobytes() |
|
|
|
counter_off = atomic_long_type.get_type()['counter'].bitpos // 8 |
|
|
|
sv_off = prb_desc_type.get_type()['state_var'].bitpos // 8 |
|
|
|
off = prb_desc_type.get_type()['text_blk_lpos'].bitpos // 8 |
|
begin_off = off + (prb_data_blk_lpos_type.get_type()['begin'].bitpos // 8) |
|
next_off = off + (prb_data_blk_lpos_type.get_type()['next'].bitpos // 8) |
|
|
|
ts_off = printk_info_type.get_type()['ts_nsec'].bitpos // 8 |
|
len_off = printk_info_type.get_type()['text_len'].bitpos // 8 |
|
|
|
# definitions from kernel/printk/printk_ringbuffer.h |
|
desc_committed = 1 |
|
desc_finalized = 2 |
|
desc_sv_bits = utils.get_long_type().sizeof * 8 |
|
desc_flags_shift = desc_sv_bits - 2 |
|
desc_flags_mask = 3 << desc_flags_shift |
|
desc_id_mask = ~desc_flags_mask |
|
|
|
# read in tail and head descriptor ids |
|
off = prb_desc_ring_type.get_type()['tail_id'].bitpos // 8 |
|
tail_id = utils.read_u64(desc_ring, off + counter_off) |
|
off = prb_desc_ring_type.get_type()['head_id'].bitpos // 8 |
|
head_id = utils.read_u64(desc_ring, off + counter_off) |
|
|
|
did = tail_id |
|
while True: |
|
ind = did % desc_ring_count |
|
desc_off = desc_sz * ind |
|
info_off = info_sz * ind |
|
|
|
# skip non-committed record |
|
state = 3 & (utils.read_u64(descs, desc_off + sv_off + |
|
counter_off) >> desc_flags_shift) |
|
if state != desc_committed and state != desc_finalized: |
|
if did == head_id: |
|
break |
|
did = (did + 1) & desc_id_mask |
|
continue |
|
|
|
begin = utils.read_ulong(descs, desc_off + begin_off) % text_data_sz |
|
end = utils.read_ulong(descs, desc_off + next_off) % text_data_sz |
|
|
|
# handle data-less record |
|
if begin & 1 == 1: |
|
text = "" |
|
else: |
|
# handle wrapping data block |
|
if begin > end: |
|
begin = 0 |
|
|
|
# skip over descriptor id |
|
text_start = begin + utils.get_long_type().sizeof |
|
|
|
text_len = utils.read_u16(infos, info_off + len_off) |
|
|
|
# handle truncated message |
|
if end - text_start < text_len: |
|
text_len = end - text_start |
|
|
|
text = text_data[text_start:text_start + text_len].decode( |
|
encoding='utf8', errors='replace') |
|
|
|
time_stamp = utils.read_u64(infos, info_off + ts_off) |
|
|
|
for line in text.splitlines(): |
|
msg = u"[{time:12.6f}] {line}\n".format( |
|
time=time_stamp / 1000000000.0, |
|
line=line) |
|
# With python2 gdb.write will attempt to convert unicode to |
|
# ascii and might fail so pass an utf8-encoded str instead. |
|
if sys.hexversion < 0x03000000: |
|
msg = msg.encode(encoding='utf8', errors='replace') |
|
gdb.write(msg) |
|
|
|
if did == head_id: |
|
break |
|
did = (did + 1) & desc_id_mask |
|
|
|
|
|
LxDmesg()
|
|
|