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Randy Dunlapb67ad182008-11-12 13:26:55 -08001If variable is of Type, use printk format specifier:
2---------------------------------------------------------
3 int %d or %x
4 unsigned int %u or %x
5 long %ld or %lx
6 unsigned long %lu or %lx
7 long long %lld or %llx
8 unsigned long long %llu or %llx
9 size_t %zu or %zx
10 ssize_t %zd or %zx
Geert Uytterhoevene8a7ba52015-04-15 16:17:17 -070011 s32 %d or %x
12 u32 %u or %x
13 s64 %lld or %llx
14 u64 %llu or %llx
15
16If <type> is dependent on a config option for its size (e.g., sector_t,
17blkcnt_t) or is architecture-dependent for its size (e.g., tcflag_t), use a
18format specifier of its largest possible type and explicitly cast to it.
19Example:
20
21 printk("test: sector number/total blocks: %llu/%llu\n",
22 (unsigned long long)sector, (unsigned long long)blockcount);
23
24Reminder: sizeof() result is of type size_t.
25
Randy Dunlapb67ad182008-11-12 13:26:55 -080026
Andrew Murray04c55712011-06-15 12:57:09 -070027Raw pointer value SHOULD be printed with %p. The kernel supports
28the following extended format specifiers for pointer types:
29
30Symbols/Function Pointers:
31
32 %pF versatile_init+0x0/0x110
33 %pf versatile_init
34 %pS versatile_init+0x0/0x110
Joe Perchesb0d33c22012-12-12 10:18:50 -080035 %pSR versatile_init+0x9/0x110
36 (with __builtin_extract_return_addr() translation)
Andrew Murray04c55712011-06-15 12:57:09 -070037 %ps versatile_init
38 %pB prev_fn_of_versatile_init+0x88/0x88
39
40 For printing symbols and function pointers. The 'S' and 's' specifiers
41 result in the symbol name with ('S') or without ('s') offsets. Where
42 this is used on a kernel without KALLSYMS - the symbol address is
43 printed instead.
44
45 The 'B' specifier results in the symbol name with offsets and should be
46 used when printing stack backtraces. The specifier takes into
47 consideration the effect of compiler optimisations which may occur
48 when tail-call's are used and marked with the noreturn GCC attribute.
49
50 On ia64, ppc64 and parisc64 architectures function pointers are
51 actually function descriptors which must first be resolved. The 'F' and
52 'f' specifiers perform this resolution and then provide the same
53 functionality as the 'S' and 's' specifiers.
54
55Kernel Pointers:
56
57 %pK 0x01234567 or 0x0123456789abcdef
58
59 For printing kernel pointers which should be hidden from unprivileged
60 users. The behaviour of %pK depends on the kptr_restrict sysctl - see
61 Documentation/sysctl/kernel.txt for more details.
62
63Struct Resources:
64
65 %pr [mem 0x60000000-0x6fffffff flags 0x2200] or
66 [mem 0x0000000060000000-0x000000006fffffff flags 0x2200]
67 %pR [mem 0x60000000-0x6fffffff pref] or
68 [mem 0x0000000060000000-0x000000006fffffff pref]
69
70 For printing struct resources. The 'R' and 'r' specifiers result in a
71 printed resource with ('R') or without ('r') a decoded flags member.
Geert Uytterhoeven73306602015-04-15 16:17:14 -070072 Passed by reference.
Andrew Murray04c55712011-06-15 12:57:09 -070073
Joe Perchesaaf07622014-01-23 15:54:17 -080074Physical addresses types phys_addr_t:
Stepan Moskovchenko7d799212013-02-21 16:43:09 -080075
Joe Perchesaaf07622014-01-23 15:54:17 -080076 %pa[p] 0x01234567 or 0x0123456789abcdef
Stepan Moskovchenko7d799212013-02-21 16:43:09 -080077
78 For printing a phys_addr_t type (and its derivatives, such as
79 resource_size_t) which can vary based on build options, regardless of
80 the width of the CPU data path. Passed by reference.
81
Joe Perchesaaf07622014-01-23 15:54:17 -080082DMA addresses types dma_addr_t:
83
84 %pad 0x01234567 or 0x0123456789abcdef
85
86 For printing a dma_addr_t type which can vary based on build options,
87 regardless of the width of the CPU data path. Passed by reference.
88
Andy Shevchenko71dca952014-10-13 15:55:18 -070089Raw buffer as an escaped string:
90
91 %*pE[achnops]
92
93 For printing raw buffer as an escaped string. For the following buffer
94
95 1b 62 20 5c 43 07 22 90 0d 5d
96
97 few examples show how the conversion would be done (the result string
98 without surrounding quotes):
99
100 %*pE "\eb \C\a"\220\r]"
101 %*pEhp "\x1bb \C\x07"\x90\x0d]"
102 %*pEa "\e\142\040\\\103\a\042\220\r\135"
103
104 The conversion rules are applied according to an optional combination
105 of flags (see string_escape_mem() kernel documentation for the
106 details):
107 a - ESCAPE_ANY
108 c - ESCAPE_SPECIAL
109 h - ESCAPE_HEX
110 n - ESCAPE_NULL
111 o - ESCAPE_OCTAL
112 p - ESCAPE_NP
113 s - ESCAPE_SPACE
114 By default ESCAPE_ANY_NP is used.
115
116 ESCAPE_ANY_NP is the sane choice for many cases, in particularly for
117 printing SSIDs.
118
119 If field width is omitted the 1 byte only will be escaped.
120
Andy Shevchenko31550a12012-07-30 14:40:27 -0700121Raw buffer as a hex string:
122 %*ph 00 01 02 ... 3f
123 %*phC 00:01:02: ... :3f
124 %*phD 00-01-02- ... -3f
125 %*phN 000102 ... 3f
126
127 For printing a small buffers (up to 64 bytes long) as a hex string with
128 certain separator. For the larger buffers consider to use
129 print_hex_dump().
130
Andrew Murray04c55712011-06-15 12:57:09 -0700131MAC/FDDI addresses:
132
133 %pM 00:01:02:03:04:05
Andrei Emeltchenko76597ff92012-07-30 14:40:23 -0700134 %pMR 05:04:03:02:01:00
Andrew Murray04c55712011-06-15 12:57:09 -0700135 %pMF 00-01-02-03-04-05
136 %pm 000102030405
Andy Shevchenko7c591542012-10-04 17:12:33 -0700137 %pmR 050403020100
Andrew Murray04c55712011-06-15 12:57:09 -0700138
139 For printing 6-byte MAC/FDDI addresses in hex notation. The 'M' and 'm'
140 specifiers result in a printed address with ('M') or without ('m') byte
141 separators. The default byte separator is the colon (':').
142
143 Where FDDI addresses are concerned the 'F' specifier can be used after
144 the 'M' specifier to use dash ('-') separators instead of the default
145 separator.
146
Andrei Emeltchenko76597ff92012-07-30 14:40:23 -0700147 For Bluetooth addresses the 'R' specifier shall be used after the 'M'
148 specifier to use reversed byte order suitable for visual interpretation
149 of Bluetooth addresses which are in the little endian order.
150
Geert Uytterhoeven73306602015-04-15 16:17:14 -0700151 Passed by reference.
152
Andrew Murray04c55712011-06-15 12:57:09 -0700153IPv4 addresses:
154
155 %pI4 1.2.3.4
156 %pi4 001.002.003.004
Daniel Borkmann8ecada12013-06-28 15:49:39 +0200157 %p[Ii]4[hnbl]
Andrew Murray04c55712011-06-15 12:57:09 -0700158
159 For printing IPv4 dot-separated decimal addresses. The 'I4' and 'i4'
160 specifiers result in a printed address with ('i4') or without ('I4')
161 leading zeros.
162
163 The additional 'h', 'n', 'b', and 'l' specifiers are used to specify
164 host, network, big or little endian order addresses respectively. Where
165 no specifier is provided the default network/big endian order is used.
166
Geert Uytterhoeven73306602015-04-15 16:17:14 -0700167 Passed by reference.
168
Andrew Murray04c55712011-06-15 12:57:09 -0700169IPv6 addresses:
170
171 %pI6 0001:0002:0003:0004:0005:0006:0007:0008
172 %pi6 00010002000300040005000600070008
173 %pI6c 1:2:3:4:5:6:7:8
174
175 For printing IPv6 network-order 16-bit hex addresses. The 'I6' and 'i6'
176 specifiers result in a printed address with ('I6') or without ('i6')
177 colon-separators. Leading zeros are always used.
178
179 The additional 'c' specifier can be used with the 'I' specifier to
180 print a compressed IPv6 address as described by
181 http://tools.ietf.org/html/rfc5952
182
Geert Uytterhoeven73306602015-04-15 16:17:14 -0700183 Passed by reference.
184
Daniel Borkmann10679642013-06-28 19:49:39 +0200185IPv4/IPv6 addresses (generic, with port, flowinfo, scope):
186
187 %pIS 1.2.3.4 or 0001:0002:0003:0004:0005:0006:0007:0008
188 %piS 001.002.003.004 or 00010002000300040005000600070008
189 %pISc 1.2.3.4 or 1:2:3:4:5:6:7:8
190 %pISpc 1.2.3.4:12345 or [1:2:3:4:5:6:7:8]:12345
191 %p[Ii]S[pfschnbl]
192
193 For printing an IP address without the need to distinguish whether it's
194 of type AF_INET or AF_INET6, a pointer to a valid 'struct sockaddr',
195 specified through 'IS' or 'iS', can be passed to this format specifier.
196
197 The additional 'p', 'f', and 's' specifiers are used to specify port
198 (IPv4, IPv6), flowinfo (IPv6) and scope (IPv6). Ports have a ':' prefix,
199 flowinfo a '/' and scope a '%', each followed by the actual value.
200
201 In case of an IPv6 address the compressed IPv6 address as described by
202 http://tools.ietf.org/html/rfc5952 is being used if the additional
203 specifier 'c' is given. The IPv6 address is surrounded by '[', ']' in
204 case of additional specifiers 'p', 'f' or 's' as suggested by
205 https://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-07
206
207 In case of IPv4 addresses, the additional 'h', 'n', 'b', and 'l'
208 specifiers can be used as well and are ignored in case of an IPv6
209 address.
210
Geert Uytterhoeven73306602015-04-15 16:17:14 -0700211 Passed by reference.
212
Daniel Borkmann10679642013-06-28 19:49:39 +0200213 Further examples:
214
215 %pISfc 1.2.3.4 or [1:2:3:4:5:6:7:8]/123456789
216 %pISsc 1.2.3.4 or [1:2:3:4:5:6:7:8]%1234567890
217 %pISpfc 1.2.3.4:12345 or [1:2:3:4:5:6:7:8]:12345/123456789
218
Andrew Murray04c55712011-06-15 12:57:09 -0700219UUID/GUID addresses:
220
221 %pUb 00010203-0405-0607-0809-0a0b0c0d0e0f
222 %pUB 00010203-0405-0607-0809-0A0B0C0D0E0F
223 %pUl 03020100-0504-0706-0809-0a0b0c0e0e0f
224 %pUL 03020100-0504-0706-0809-0A0B0C0E0E0F
225
226 For printing 16-byte UUID/GUIDs addresses. The additional 'l', 'L',
227 'b' and 'B' specifiers are used to specify a little endian order in
228 lower ('l') or upper case ('L') hex characters - and big endian order
229 in lower ('b') or upper case ('B') hex characters.
230
Rasmus Villemoesd181b712015-02-24 15:26:06 +0100231 Where no additional specifiers are used the default big endian
Andrew Murray04c55712011-06-15 12:57:09 -0700232 order with lower case hex characters will be printed.
233
Geert Uytterhoeven73306602015-04-15 16:17:14 -0700234 Passed by reference.
235
Al Viro4b6ccca2013-09-03 12:00:44 -0400236dentry names:
237 %pd{,2,3,4}
238 %pD{,2,3,4}
239
240 For printing dentry name; if we race with d_move(), the name might be
241 a mix of old and new ones, but it won't oops. %pd dentry is a safer
242 equivalent of %s dentry->d_name.name we used to use, %pd<n> prints
243 n last components. %pD does the same thing for struct file.
244
Geert Uytterhoeven73306602015-04-15 16:17:14 -0700245 Passed by reference.
246
Andrew Murray04c55712011-06-15 12:57:09 -0700247struct va_format:
248
249 %pV
250
251 For printing struct va_format structures. These contain a format string
252 and va_list as follows:
253
254 struct va_format {
255 const char *fmt;
256 va_list *va;
257 };
258
259 Do not use this feature without some mechanism to verify the
260 correctness of the format string and va_list arguments.
Randy Dunlapb67ad182008-11-12 13:26:55 -0800261
Geert Uytterhoeven73306602015-04-15 16:17:14 -0700262 Passed by reference.
263
Geert Uytterhoeven900cca22015-04-15 16:17:20 -0700264struct clk:
265
266 %pC pll1
267 %pCn pll1
268 %pCr 1560000000
269
270 For printing struct clk structures. '%pC' and '%pCn' print the name
271 (Common Clock Framework) or address (legacy clock framework) of the
272 structure; '%pCr' prints the current clock rate.
273
274 Passed by reference.
275
Wang Longd0724962015-02-26 03:28:25 +0000276bitmap and its derivatives such as cpumask and nodemask:
277
278 %*pb 0779
279 %*pbl 0,3-6,8-10
280
281 For printing bitmap and its derivatives such as cpumask and nodemask,
282 %*pb output the bitmap with field width as the number of bits and %*pbl
283 output the bitmap as range list with field width as the number of bits.
284
Linus Torvaldsd6a24d02015-04-18 11:10:49 -0400285 Passed by reference.
Randy Dunlapb67ad182008-11-12 13:26:55 -0800286
287Thank you for your cooperation and attention.
288
289
Randy Dunlap755727b2013-03-08 12:43:35 -0800290By Randy Dunlap <rdunlap@infradead.org> and
Andrew Murray04c55712011-06-15 12:57:09 -0700291Andrew Murray <amurray@mpc-data.co.uk>