1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
|
If variable is of Type, use printk format specifier:
---------------------------------------------------------
int %d or %x
unsigned int %u or %x
long %ld or %lx
unsigned long %lu or %lx
long long %lld or %llx
unsigned long long %llu or %llx
size_t %zu or %zx
ssize_t %zd or %zx
Raw pointer value SHOULD be printed with %p. The kernel supports
the following extended format specifiers for pointer types:
Symbols/Function Pointers:
%pF versatile_init+0x0/0x110
%pf versatile_init
%pS versatile_init+0x0/0x110
%pSR versatile_init+0x9/0x110
(with __builtin_extract_return_addr() translation)
%ps versatile_init
%pB prev_fn_of_versatile_init+0x88/0x88
For printing symbols and function pointers. The 'S' and 's' specifiers
result in the symbol name with ('S') or without ('s') offsets. Where
this is used on a kernel without KALLSYMS - the symbol address is
printed instead.
The 'B' specifier results in the symbol name with offsets and should be
used when printing stack backtraces. The specifier takes into
consideration the effect of compiler optimisations which may occur
when tail-call's are used and marked with the noreturn GCC attribute.
On ia64, ppc64 and parisc64 architectures function pointers are
actually function descriptors which must first be resolved. The 'F' and
'f' specifiers perform this resolution and then provide the same
functionality as the 'S' and 's' specifiers.
Kernel Pointers:
%pK 0x01234567 or 0x0123456789abcdef
For printing kernel pointers which should be hidden from unprivileged
users. The behaviour of %pK depends on the kptr_restrict sysctl - see
Documentation/sysctl/kernel.txt for more details.
Struct Resources:
%pr [mem 0x60000000-0x6fffffff flags 0x2200] or
[mem 0x0000000060000000-0x000000006fffffff flags 0x2200]
%pR [mem 0x60000000-0x6fffffff pref] or
[mem 0x0000000060000000-0x000000006fffffff pref]
For printing struct resources. The 'R' and 'r' specifiers result in a
printed resource with ('R') or without ('r') a decoded flags member.
Physical addresses types phys_addr_t:
%pa[p] 0x01234567 or 0x0123456789abcdef
For printing a phys_addr_t type (and its derivatives, such as
resource_size_t) which can vary based on build options, regardless of
the width of the CPU data path. Passed by reference.
DMA addresses types dma_addr_t:
%pad 0x01234567 or 0x0123456789abcdef
For printing a dma_addr_t type which can vary based on build options,
regardless of the width of the CPU data path. Passed by reference.
Raw buffer as an escaped string:
%*pE[achnops]
For printing raw buffer as an escaped string. For the following buffer
1b 62 20 5c 43 07 22 90 0d 5d
few examples show how the conversion would be done (the result string
without surrounding quotes):
%*pE "\eb \C\a"\220\r]"
%*pEhp "\x1bb \C\x07"\x90\x0d]"
%*pEa "\e\142\040\\\103\a\042\220\r\135"
The conversion rules are applied according to an optional combination
of flags (see string_escape_mem() kernel documentation for the
details):
a - ESCAPE_ANY
c - ESCAPE_SPECIAL
h - ESCAPE_HEX
n - ESCAPE_NULL
o - ESCAPE_OCTAL
p - ESCAPE_NP
s - ESCAPE_SPACE
By default ESCAPE_ANY_NP is used.
ESCAPE_ANY_NP is the sane choice for many cases, in particularly for
printing SSIDs.
If field width is omitted the 1 byte only will be escaped.
Raw buffer as a hex string:
%*ph 00 01 02 ... 3f
%*phC 00:01:02: ... :3f
%*phD 00-01-02- ... -3f
%*phN 000102 ... 3f
For printing a small buffers (up to 64 bytes long) as a hex string with
certain separator. For the larger buffers consider to use
print_hex_dump().
MAC/FDDI addresses:
%pM 00:01:02:03:04:05
%pMR 05:04:03:02:01:00
%pMF 00-01-02-03-04-05
%pm 000102030405
%pmR 050403020100
For printing 6-byte MAC/FDDI addresses in hex notation. The 'M' and 'm'
specifiers result in a printed address with ('M') or without ('m') byte
separators. The default byte separator is the colon (':').
Where FDDI addresses are concerned the 'F' specifier can be used after
the 'M' specifier to use dash ('-') separators instead of the default
separator.
For Bluetooth addresses the 'R' specifier shall be used after the 'M'
specifier to use reversed byte order suitable for visual interpretation
of Bluetooth addresses which are in the little endian order.
IPv4 addresses:
%pI4 1.2.3.4
%pi4 001.002.003.004
%p[Ii]4[hnbl]
For printing IPv4 dot-separated decimal addresses. The 'I4' and 'i4'
specifiers result in a printed address with ('i4') or without ('I4')
leading zeros.
The additional 'h', 'n', 'b', and 'l' specifiers are used to specify
host, network, big or little endian order addresses respectively. Where
no specifier is provided the default network/big endian order is used.
IPv6 addresses:
%pI6 0001:0002:0003:0004:0005:0006:0007:0008
%pi6 00010002000300040005000600070008
%pI6c 1:2:3:4:5:6:7:8
For printing IPv6 network-order 16-bit hex addresses. The 'I6' and 'i6'
specifiers result in a printed address with ('I6') or without ('i6')
colon-separators. Leading zeros are always used.
The additional 'c' specifier can be used with the 'I' specifier to
print a compressed IPv6 address as described by
http://tools.ietf.org/html/rfc5952
IPv4/IPv6 addresses (generic, with port, flowinfo, scope):
%pIS 1.2.3.4 or 0001:0002:0003:0004:0005:0006:0007:0008
%piS 001.002.003.004 or 00010002000300040005000600070008
%pISc 1.2.3.4 or 1:2:3:4:5:6:7:8
%pISpc 1.2.3.4:12345 or [1:2:3:4:5:6:7:8]:12345
%p[Ii]S[pfschnbl]
For printing an IP address without the need to distinguish whether it's
of type AF_INET or AF_INET6, a pointer to a valid 'struct sockaddr',
specified through 'IS' or 'iS', can be passed to this format specifier.
The additional 'p', 'f', and 's' specifiers are used to specify port
(IPv4, IPv6), flowinfo (IPv6) and scope (IPv6). Ports have a ':' prefix,
flowinfo a '/' and scope a '%', each followed by the actual value.
In case of an IPv6 address the compressed IPv6 address as described by
http://tools.ietf.org/html/rfc5952 is being used if the additional
specifier 'c' is given. The IPv6 address is surrounded by '[', ']' in
case of additional specifiers 'p', 'f' or 's' as suggested by
https://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-07
In case of IPv4 addresses, the additional 'h', 'n', 'b', and 'l'
specifiers can be used as well and are ignored in case of an IPv6
address.
Further examples:
%pISfc 1.2.3.4 or [1:2:3:4:5:6:7:8]/123456789
%pISsc 1.2.3.4 or [1:2:3:4:5:6:7:8]%1234567890
%pISpfc 1.2.3.4:12345 or [1:2:3:4:5:6:7:8]:12345/123456789
UUID/GUID addresses:
%pUb 00010203-0405-0607-0809-0a0b0c0d0e0f
%pUB 00010203-0405-0607-0809-0A0B0C0D0E0F
%pUl 03020100-0504-0706-0809-0a0b0c0e0e0f
%pUL 03020100-0504-0706-0809-0A0B0C0E0E0F
For printing 16-byte UUID/GUIDs addresses. The additional 'l', 'L',
'b' and 'B' specifiers are used to specify a little endian order in
lower ('l') or upper case ('L') hex characters - and big endian order
in lower ('b') or upper case ('B') hex characters.
Where no additional specifiers are used the default little endian
order with lower case hex characters will be printed.
dentry names:
%pd{,2,3,4}
%pD{,2,3,4}
For printing dentry name; if we race with d_move(), the name might be
a mix of old and new ones, but it won't oops. %pd dentry is a safer
equivalent of %s dentry->d_name.name we used to use, %pd<n> prints
n last components. %pD does the same thing for struct file.
struct va_format:
%pV
For printing struct va_format structures. These contain a format string
and va_list as follows:
struct va_format {
const char *fmt;
va_list *va;
};
Do not use this feature without some mechanism to verify the
correctness of the format string and va_list arguments.
u64 SHOULD be printed with %llu/%llx:
printk("%llu", u64_var);
s64 SHOULD be printed with %lld/%llx:
printk("%lld", s64_var);
If <type> is dependent on a config option for its size (e.g., sector_t,
blkcnt_t) or is architecture-dependent for its size (e.g., tcflag_t), use a
format specifier of its largest possible type and explicitly cast to it.
Example:
printk("test: sector number/total blocks: %llu/%llu\n",
(unsigned long long)sector, (unsigned long long)blockcount);
Reminder: sizeof() result is of type size_t.
Thank you for your cooperation and attention.
By Randy Dunlap <rdunlap@infradead.org> and
Andrew Murray <amurray@mpc-data.co.uk>
|
