[GitHub/moto-9609/android_kernel_motorola_exynos9610.git] / Documentation / printk-formats.txt

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.
	Passed by reference.

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.

	Passed by reference.

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.

	Passed by reference.

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

	Passed by reference.

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.

	Passed by reference.

	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.

	Passed by reference.

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.

	Passed by reference.

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.

	Passed by reference.

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>
Commit	Line	Data
b67ad18b RD	1	If 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
	11
04c55715 AM	12	Raw pointer value SHOULD be printed with %p. The kernel supports
	13	the following extended format specifiers for pointer types:
	14
	15	Symbols/Function Pointers:
	16
	17	%pF versatile_init+0x0/0x110
	18	%pf versatile_init
	19	%pS versatile_init+0x0/0x110
b0d33c2b JP	20	%pSR versatile_init+0x9/0x110
b0d33c2b JP	21	(with __builtin_extract_return_addr() translation)
04c55715 AM	22	%ps versatile_init
	23	%pB prev_fn_of_versatile_init+0x88/0x88
	24
	25	For printing symbols and function pointers. The 'S' and 's' specifiers
	26	result in the symbol name with ('S') or without ('s') offsets. Where
	27	this is used on a kernel without KALLSYMS - the symbol address is
	28	printed instead.
	29
	30	The 'B' specifier results in the symbol name with offsets and should be
	31	used when printing stack backtraces. The specifier takes into
	32	consideration the effect of compiler optimisations which may occur
	33	when tail-call's are used and marked with the noreturn GCC attribute.
	34
	35	On ia64, ppc64 and parisc64 architectures function pointers are
	36	actually function descriptors which must first be resolved. The 'F' and
	37	'f' specifiers perform this resolution and then provide the same
	38	functionality as the 'S' and 's' specifiers.
	39
	40	Kernel Pointers:
	41
	42	%pK 0x01234567 or 0x0123456789abcdef
	43
	44	For printing kernel pointers which should be hidden from unprivileged
	45	users. The behaviour of %pK depends on the kptr_restrict sysctl - see
	46	Documentation/sysctl/kernel.txt for more details.
	47
	48	Struct Resources:
	49
	50	%pr [mem 0x60000000-0x6fffffff flags 0x2200] or
	51	[mem 0x0000000060000000-0x000000006fffffff flags 0x2200]
	52	%pR [mem 0x60000000-0x6fffffff pref] or
	53	[mem 0x0000000060000000-0x000000006fffffff pref]
	54
	55	For printing struct resources. The 'R' and 'r' specifiers result in a
	56	printed resource with ('R') or without ('r') a decoded flags member.
7330660e	57	Passed by reference.
04c55715	58
aaf07621	59	Physical addresses types phys_addr_t:
7d799210	60
aaf07621	61	%pa[p] 0x01234567 or 0x0123456789abcdef
7d799210 SM	62
	63	For printing a phys_addr_t type (and its derivatives, such as
	64	resource_size_t) which can vary based on build options, regardless of
	65	the width of the CPU data path. Passed by reference.
	66
aaf07621 JP	67	DMA addresses types dma_addr_t:
	68
	69	%pad 0x01234567 or 0x0123456789abcdef
	70
	71	For printing a dma_addr_t type which can vary based on build options,
	72	regardless of the width of the CPU data path. Passed by reference.
	73
71dca95d AS	74	Raw buffer as an escaped string:
	75
	76	%*pE[achnops]
	77
	78	For printing raw buffer as an escaped string. For the following buffer
	79
	80	1b 62 20 5c 43 07 22 90 0d 5d
	81
	82	few examples show how the conversion would be done (the result string
	83	without surrounding quotes):
	84
	85	%*pE "\eb \C\a"\220\r]"
	86	%*pEhp "\x1bb \C\x07"\x90\x0d]"
	87	%*pEa "\e\142\040\\\103\a\042\220\r\135"
	88
	89	The conversion rules are applied according to an optional combination
	90	of flags (see string_escape_mem() kernel documentation for the
	91	details):
	92	a - ESCAPE_ANY
	93	c - ESCAPE_SPECIAL
	94	h - ESCAPE_HEX
	95	n - ESCAPE_NULL
	96	o - ESCAPE_OCTAL
	97	p - ESCAPE_NP
	98	s - ESCAPE_SPACE
	99	By default ESCAPE_ANY_NP is used.
	100
	101	ESCAPE_ANY_NP is the sane choice for many cases, in particularly for
	102	printing SSIDs.
	103
	104	If field width is omitted the 1 byte only will be escaped.
	105
31550a16 AS	106	Raw buffer as a hex string:
	107	%*ph 00 01 02 ... 3f
	108	%*phC 00:01:02: ... :3f
	109	%*phD 00-01-02- ... -3f
	110	%*phN 000102 ... 3f
	111
	112	For printing a small buffers (up to 64 bytes long) as a hex string with
	113	certain separator. For the larger buffers consider to use
	114	print_hex_dump().
	115
04c55715 AM	116	MAC/FDDI addresses:
	117
	118	%pM 00:01:02:03:04:05
76597ff9	119	%pMR 05:04:03:02:01:00
04c55715 AM	120	%pMF 00-01-02-03-04-05
04c55715 AM	121	%pm 000102030405
7c59154e	122	%pmR 050403020100
04c55715 AM	123
	124	For printing 6-byte MAC/FDDI addresses in hex notation. The 'M' and 'm'
	125	specifiers result in a printed address with ('M') or without ('m') byte
	126	separators. The default byte separator is the colon (':').
	127
	128	Where FDDI addresses are concerned the 'F' specifier can be used after
	129	the 'M' specifier to use dash ('-') separators instead of the default
	130	separator.
	131
76597ff9 AE	132	For Bluetooth addresses the 'R' specifier shall be used after the 'M'
	133	specifier to use reversed byte order suitable for visual interpretation
	134	of Bluetooth addresses which are in the little endian order.
	135
7330660e GU	136	Passed by reference.
7330660e GU	137
04c55715 AM	138	IPv4 addresses:
	139
	140	%pI4 1.2.3.4
	141	%pi4 001.002.003.004
8ecada16	142	%p[Ii]4[hnbl]
04c55715 AM	143
	144	For printing IPv4 dot-separated decimal addresses. The 'I4' and 'i4'
	145	specifiers result in a printed address with ('i4') or without ('I4')
	146	leading zeros.
	147
	148	The additional 'h', 'n', 'b', and 'l' specifiers are used to specify
	149	host, network, big or little endian order addresses respectively. Where
	150	no specifier is provided the default network/big endian order is used.
	151
7330660e GU	152	Passed by reference.
7330660e GU	153
04c55715 AM	154	IPv6 addresses:
	155
	156	%pI6 0001:0002:0003:0004:0005:0006:0007:0008
	157	%pi6 00010002000300040005000600070008
	158	%pI6c 1:2:3:4:5:6:7:8
	159
	160	For printing IPv6 network-order 16-bit hex addresses. The 'I6' and 'i6'
	161	specifiers result in a printed address with ('I6') or without ('i6')
	162	colon-separators. Leading zeros are always used.
	163
	164	The additional 'c' specifier can be used with the 'I' specifier to
	165	print a compressed IPv6 address as described by
	166	http://tools.ietf.org/html/rfc5952
	167
7330660e GU	168	Passed by reference.
7330660e GU	169
10679643 DB	170	IPv4/IPv6 addresses (generic, with port, flowinfo, scope):
	171
	172	%pIS 1.2.3.4 or 0001:0002:0003:0004:0005:0006:0007:0008
	173	%piS 001.002.003.004 or 00010002000300040005000600070008
	174	%pISc 1.2.3.4 or 1:2:3:4:5:6:7:8
	175	%pISpc 1.2.3.4:12345 or [1:2:3:4:5:6:7:8]:12345
	176	%p[Ii]S[pfschnbl]
	177
	178	For printing an IP address without the need to distinguish whether it's
	179	of type AF_INET or AF_INET6, a pointer to a valid 'struct sockaddr',
	180	specified through 'IS' or 'iS', can be passed to this format specifier.
	181
	182	The additional 'p', 'f', and 's' specifiers are used to specify port
	183	(IPv4, IPv6), flowinfo (IPv6) and scope (IPv6). Ports have a ':' prefix,
	184	flowinfo a '/' and scope a '%', each followed by the actual value.
	185
	186	In case of an IPv6 address the compressed IPv6 address as described by
	187	http://tools.ietf.org/html/rfc5952 is being used if the additional
	188	specifier 'c' is given. The IPv6 address is surrounded by '[', ']' in
	189	case of additional specifiers 'p', 'f' or 's' as suggested by
	190	https://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-07
	191
	192	In case of IPv4 addresses, the additional 'h', 'n', 'b', and 'l'
	193	specifiers can be used as well and are ignored in case of an IPv6
	194	address.
	195
7330660e GU	196	Passed by reference.
7330660e GU	197
10679643 DB	198	Further examples:
	199
	200	%pISfc 1.2.3.4 or [1:2:3:4:5:6:7:8]/123456789
	201	%pISsc 1.2.3.4 or [1:2:3:4:5:6:7:8]%1234567890
	202	%pISpfc 1.2.3.4:12345 or [1:2:3:4:5:6:7:8]:12345/123456789
	203
04c55715 AM	204	UUID/GUID addresses:
	205
	206	%pUb 00010203-0405-0607-0809-0a0b0c0d0e0f
	207	%pUB 00010203-0405-0607-0809-0A0B0C0D0E0F
	208	%pUl 03020100-0504-0706-0809-0a0b0c0e0e0f
	209	%pUL 03020100-0504-0706-0809-0A0B0C0E0E0F
	210
	211	For printing 16-byte UUID/GUIDs addresses. The additional 'l', 'L',
	212	'b' and 'B' specifiers are used to specify a little endian order in
	213	lower ('l') or upper case ('L') hex characters - and big endian order
	214	in lower ('b') or upper case ('B') hex characters.
	215
	216	Where no additional specifiers are used the default little endian
	217	order with lower case hex characters will be printed.
	218
7330660e GU	219	Passed by reference.
7330660e GU	220
4b6ccca7 AV	221	dentry names:
	222	%pd{,2,3,4}
	223	%pD{,2,3,4}
	224
	225	For printing dentry name; if we race with d_move(), the name might be
	226	a mix of old and new ones, but it won't oops. %pd dentry is a safer
	227	equivalent of %s dentry->d_name.name we used to use, %pd<n> prints
	228	n last components. %pD does the same thing for struct file.
	229
7330660e GU	230	Passed by reference.
7330660e GU	231
04c55715 AM	232	struct va_format:
	233
	234	%pV
	235
	236	For printing struct va_format structures. These contain a format string
	237	and va_list as follows:
	238
	239	struct va_format {
	240	const char *fmt;
	241	va_list *va;
	242	};
	243
	244	Do not use this feature without some mechanism to verify the
	245	correctness of the format string and va_list arguments.
b67ad18b	246
7330660e GU	247	Passed by reference.
7330660e GU	248
15a0b3fb	249	u64 SHOULD be printed with %llu/%llx:
b67ad18b	250
2a7930bd	251	printk("%llu", u64_var);
b67ad18b	252
15a0b3fb	253	s64 SHOULD be printed with %lld/%llx:
b67ad18b	254
2a7930bd	255	printk("%lld", s64_var);
b67ad18b RD	256
b67ad18b RD	257	If <type> is dependent on a config option for its size (e.g., sector_t,
7d799210 SM	258	blkcnt_t) or is architecture-dependent for its size (e.g., tcflag_t), use a
	259	format specifier of its largest possible type and explicitly cast to it.
	260	Example:
b67ad18b RD	261
	262	printk("test: sector number/total blocks: %llu/%llu\n",
	263	(unsigned long long)sector, (unsigned long long)blockcount);
	264
	265	Reminder: sizeof() result is of type size_t.
	266
	267	Thank you for your cooperation and attention.
	268
	269
755727b7	270	By Randy Dunlap <rdunlap@infradead.org> and
04c55715	271	Andrew Murray <amurray@mpc-data.co.uk>