1 # 1 #
2 # gdb helper commands and functions for Linux 2 # gdb helper commands and functions for Linux kernel debugging
3 # 3 #
4 # kernel log buffer dump 4 # kernel log buffer dump
5 # 5 #
6 # Copyright (c) Siemens AG, 2011, 2012 6 # Copyright (c) Siemens AG, 2011, 2012
7 # 7 #
8 # Authors: 8 # Authors:
9 # Jan Kiszka <jan.kiszka@siemens.com> 9 # Jan Kiszka <jan.kiszka@siemens.com>
10 # 10 #
11 # This work is licensed under the terms of the 11 # This work is licensed under the terms of the GNU GPL version 2.
12 # 12 #
13 13
14 import gdb 14 import gdb
15 import sys 15 import sys
16 16
17 from linux import utils 17 from linux import utils
18 18
19 printk_info_type = utils.CachedType("struct pr 19 printk_info_type = utils.CachedType("struct printk_info")
20 prb_data_blk_lpos_type = utils.CachedType("str 20 prb_data_blk_lpos_type = utils.CachedType("struct prb_data_blk_lpos")
21 prb_desc_type = utils.CachedType("struct prb_d 21 prb_desc_type = utils.CachedType("struct prb_desc")
22 prb_desc_ring_type = utils.CachedType("struct 22 prb_desc_ring_type = utils.CachedType("struct prb_desc_ring")
23 prb_data_ring_type = utils.CachedType("struct 23 prb_data_ring_type = utils.CachedType("struct prb_data_ring")
24 printk_ringbuffer_type = utils.CachedType("str 24 printk_ringbuffer_type = utils.CachedType("struct printk_ringbuffer")
>> 25 atomic_long_type = utils.CachedType("atomic_long_t")
25 26
26 class LxDmesg(gdb.Command): 27 class LxDmesg(gdb.Command):
27 """Print Linux kernel log buffer.""" 28 """Print Linux kernel log buffer."""
28 29
29 def __init__(self): 30 def __init__(self):
30 super(LxDmesg, self).__init__("lx-dmes 31 super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA)
31 32
32 def invoke(self, arg, from_tty): 33 def invoke(self, arg, from_tty):
33 inf = gdb.inferiors()[0] 34 inf = gdb.inferiors()[0]
34 35
35 # read in prb structure 36 # read in prb structure
36 prb_addr = int(str(gdb.parse_and_eval( 37 prb_addr = int(str(gdb.parse_and_eval("(void *)'printk.c'::prb")).split()[0], 16)
37 sz = printk_ringbuffer_type.get_type() 38 sz = printk_ringbuffer_type.get_type().sizeof
38 prb = utils.read_memoryview(inf, prb_a 39 prb = utils.read_memoryview(inf, prb_addr, sz).tobytes()
39 40
40 # read in descriptor ring structure 41 # read in descriptor ring structure
41 off = printk_ringbuffer_type.get_type( 42 off = printk_ringbuffer_type.get_type()['desc_ring'].bitpos // 8
42 addr = prb_addr + off 43 addr = prb_addr + off
43 sz = prb_desc_ring_type.get_type().siz 44 sz = prb_desc_ring_type.get_type().sizeof
44 desc_ring = utils.read_memoryview(inf, 45 desc_ring = utils.read_memoryview(inf, addr, sz).tobytes()
45 46
46 # read in descriptor count, size, and !! 47 # read in descriptor array
47 off = prb_desc_ring_type.get_type()['c 48 off = prb_desc_ring_type.get_type()['count_bits'].bitpos // 8
48 desc_ring_count = 1 << utils.read_u32( 49 desc_ring_count = 1 << utils.read_u32(desc_ring, off)
49 desc_sz = prb_desc_type.get_type().siz 50 desc_sz = prb_desc_type.get_type().sizeof
50 off = prb_desc_ring_type.get_type()['d 51 off = prb_desc_ring_type.get_type()['descs'].bitpos // 8
51 desc_addr = utils.read_ulong(desc_ring !! 52 addr = utils.read_ulong(desc_ring, off)
>> 53 descs = utils.read_memoryview(inf, addr, desc_sz * desc_ring_count).tobytes()
52 54
53 # read in info size and address !! 55 # read in info array
54 info_sz = printk_info_type.get_type(). 56 info_sz = printk_info_type.get_type().sizeof
55 off = prb_desc_ring_type.get_type()['i 57 off = prb_desc_ring_type.get_type()['infos'].bitpos // 8
56 info_addr = utils.read_ulong(desc_ring !! 58 addr = utils.read_ulong(desc_ring, off)
>> 59 infos = utils.read_memoryview(inf, addr, info_sz * desc_ring_count).tobytes()
57 60
58 # read in text data ring structure 61 # read in text data ring structure
59 off = printk_ringbuffer_type.get_type( 62 off = printk_ringbuffer_type.get_type()['text_data_ring'].bitpos // 8
60 addr = prb_addr + off 63 addr = prb_addr + off
61 sz = prb_data_ring_type.get_type().siz 64 sz = prb_data_ring_type.get_type().sizeof
62 text_data_ring = utils.read_memoryview 65 text_data_ring = utils.read_memoryview(inf, addr, sz).tobytes()
63 66
64 # read in text data size and address !! 67 # read in text data
65 off = prb_data_ring_type.get_type()['s 68 off = prb_data_ring_type.get_type()['size_bits'].bitpos // 8
66 text_data_sz = 1 << utils.read_u32(tex 69 text_data_sz = 1 << utils.read_u32(text_data_ring, off)
67 off = prb_data_ring_type.get_type()['d 70 off = prb_data_ring_type.get_type()['data'].bitpos // 8
68 text_data_addr = utils.read_ulong(text !! 71 addr = utils.read_ulong(text_data_ring, off)
>> 72 text_data = utils.read_memoryview(inf, addr, text_data_sz).tobytes()
>> 73
>> 74 counter_off = atomic_long_type.get_type()['counter'].bitpos // 8
69 75
70 sv_off = prb_desc_type.get_type()['sta 76 sv_off = prb_desc_type.get_type()['state_var'].bitpos // 8
71 77
72 off = prb_desc_type.get_type()['text_b 78 off = prb_desc_type.get_type()['text_blk_lpos'].bitpos // 8
73 begin_off = off + (prb_data_blk_lpos_t 79 begin_off = off + (prb_data_blk_lpos_type.get_type()['begin'].bitpos // 8)
74 next_off = off + (prb_data_blk_lpos_ty 80 next_off = off + (prb_data_blk_lpos_type.get_type()['next'].bitpos // 8)
75 81
76 ts_off = printk_info_type.get_type()[' 82 ts_off = printk_info_type.get_type()['ts_nsec'].bitpos // 8
77 len_off = printk_info_type.get_type()[ 83 len_off = printk_info_type.get_type()['text_len'].bitpos // 8
78 84
79 # definitions from kernel/printk/print 85 # definitions from kernel/printk/printk_ringbuffer.h
80 desc_committed = 1 86 desc_committed = 1
81 desc_finalized = 2 87 desc_finalized = 2
82 desc_sv_bits = utils.get_long_type().s 88 desc_sv_bits = utils.get_long_type().sizeof * 8
83 desc_flags_shift = desc_sv_bits - 2 89 desc_flags_shift = desc_sv_bits - 2
84 desc_flags_mask = 3 << desc_flags_shif 90 desc_flags_mask = 3 << desc_flags_shift
85 desc_id_mask = ~desc_flags_mask 91 desc_id_mask = ~desc_flags_mask
86 92
87 # read in tail and head descriptor ids 93 # read in tail and head descriptor ids
88 off = prb_desc_ring_type.get_type()['t 94 off = prb_desc_ring_type.get_type()['tail_id'].bitpos // 8
89 tail_id = utils.read_atomic_long(desc_ !! 95 tail_id = utils.read_u64(desc_ring, off + counter_off)
90 off = prb_desc_ring_type.get_type()['h 96 off = prb_desc_ring_type.get_type()['head_id'].bitpos // 8
91 head_id = utils.read_atomic_long(desc_ !! 97 head_id = utils.read_u64(desc_ring, off + counter_off)
92 98
93 did = tail_id 99 did = tail_id
94 while True: 100 while True:
95 ind = did % desc_ring_count 101 ind = did % desc_ring_count
96 desc_off = desc_sz * ind 102 desc_off = desc_sz * ind
97 info_off = info_sz * ind 103 info_off = info_sz * ind
98 104
99 desc = utils.read_memoryview(inf, <<
100 <<
101 # skip non-committed record 105 # skip non-committed record
102 state = 3 & (utils.read_atomic_lon !! 106 state = 3 & (utils.read_u64(descs, desc_off + sv_off +
>> 107 counter_off) >> desc_flags_shift)
103 if state != desc_committed and sta 108 if state != desc_committed and state != desc_finalized:
104 if did == head_id: 109 if did == head_id:
105 break 110 break
106 did = (did + 1) & desc_id_mask 111 did = (did + 1) & desc_id_mask
107 continue 112 continue
108 113
109 begin = utils.read_ulong(desc, beg !! 114 begin = utils.read_ulong(descs, desc_off + begin_off) % text_data_sz
110 end = utils.read_ulong(desc, next_ !! 115 end = utils.read_ulong(descs, desc_off + next_off) % text_data_sz
111 <<
112 info = utils.read_memoryview(inf, <<
113 116
114 # handle data-less record 117 # handle data-less record
115 if begin & 1 == 1: 118 if begin & 1 == 1:
116 text = "" 119 text = ""
117 else: 120 else:
118 # handle wrapping data block 121 # handle wrapping data block
119 if begin > end: 122 if begin > end:
120 begin = 0 123 begin = 0
121 124
122 # skip over descriptor id 125 # skip over descriptor id
123 text_start = begin + utils.get 126 text_start = begin + utils.get_long_type().sizeof
124 127
125 text_len = utils.read_u16(info !! 128 text_len = utils.read_u16(infos, info_off + len_off)
126 129
127 # handle truncated message 130 # handle truncated message
128 if end - text_start < text_len 131 if end - text_start < text_len:
129 text_len = end - text_star 132 text_len = end - text_start
130 133
131 text_data = utils.read_memoryv !! 134 text = text_data[text_start:text_start + text_len].decode(
132 !! 135 encoding='utf8', errors='replace')
133 text = text_data[0:text_len].d <<
134 136
135 time_stamp = utils.read_u64(info, !! 137 time_stamp = utils.read_u64(infos, info_off + ts_off)
136 138
137 for line in text.splitlines(): 139 for line in text.splitlines():
138 msg = u"[{time:12.6f}] {line}\ 140 msg = u"[{time:12.6f}] {line}\n".format(
139 time=time_stamp / 10000000 141 time=time_stamp / 1000000000.0,
140 line=line) 142 line=line)
141 # With python2 gdb.write will 143 # With python2 gdb.write will attempt to convert unicode to
142 # ascii and might fail so pass 144 # ascii and might fail so pass an utf8-encoded str instead.
143 if sys.hexversion < 0x03000000 145 if sys.hexversion < 0x03000000:
144 msg = msg.encode(encoding= 146 msg = msg.encode(encoding='utf8', errors='replace')
145 gdb.write(msg) 147 gdb.write(msg)
146 148
147 if did == head_id: 149 if did == head_id:
148 break 150 break
149 did = (did + 1) & desc_id_mask 151 did = (did + 1) & desc_id_mask
150 152
151 153
152 LxDmesg() 154 LxDmesg()
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