- directory with info on the priveledge control subsystem
preempt-locking.txt
- info on locking under a preemptive kernel.
-printk-formats.txt
- - how to get printk format specifiers right
process/
- how to work with the mainline kernel development process.
pps/
flexible-arrays
librs
genalloc
+ printk-formats
Interfaces for kernel debugging
===============================
--- /dev/null
+=========================================
+How to get printk format specifiers right
+=========================================
+
+:Author: Randy Dunlap <rdunlap@infradead.org>
+:Author: Andrew Murray <amurray@mpc-data.co.uk>
+
+
+Integer types
+=============
+
+::
+
+ 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
+ s32 %d or %x
+ u32 %u or %x
+ s64 %lld or %llx
+ u64 %llu or %llx
+
+
+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() returns type size_t.
+
+The kernel's printf does not support %n. Floating point formats (%e, %f,
+%g, %a) are also not recognized, for obvious reasons. Use of any
+unsupported specifier or length qualifier results in a WARN and early
+return from vsnprintf().
+
+Pointer types
+=============
+
+A raw pointer value may be printed with %p which will hash the address
+before printing. The kernel also supports extended specifiers for printing
+pointers of different types.
+
+Plain Pointers
+--------------
+
+::
+
+ %p abcdef12 or 00000000abcdef12
+
+Pointers printed without a specifier extension (i.e unadorned %p) are
+hashed to prevent leaking information about the kernel memory layout. This
+has the added benefit of providing a unique identifier. On 64-bit machines
+the first 32 bits are zeroed. If you *really* want the address see %px
+below.
+
+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
+
+
+The ``F`` and ``f`` specifiers are for printing function pointers,
+for example, f->func, &gettimeofday. They have the same result as
+``S`` and ``s`` specifiers. But they do an extra conversion on
+ia64, ppc64 and parisc64 architectures where the function pointers
+are actually function descriptors.
+
+The ``S`` and ``s`` specifiers can be used for printing symbols
+from direct addresses, for example, __builtin_return_address(0),
+(void *)regs->ip. They result in the symbol name with (S) or
+without (s) offsets. If KALLSYMS are disabled then 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-calls are used and marked with the noreturn GCC attribute.
+
+Examples::
+
+ printk("Going to call: %pF\n", gettimeofday);
+ printk("Going to call: %pF\n", p->func);
+ printk("%s: called from %pS\n", __func__, (void *)_RET_IP_);
+ printk("%s: called from %pS\n", __func__,
+ (void *)__builtin_return_address(0));
+ printk("Faulted at %pS\n", (void *)regs->ip);
+ printk(" %s%pB\n", (reliable ? "" : "? "), (void *)*stack);
+
+Kernel Pointers
+---------------
+
+::
+
+ %pK 01234567 or 0123456789abcdef
+
+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.
+
+Unmodified Addresses
+--------------------
+
+::
+
+ %px 01234567 or 0123456789abcdef
+
+For printing pointers when you *really* want to print the address. Please
+consider whether or not you are leaking sensitive information about the
+kernel memory layout before printing pointers with %px. %px is functionally
+equivalent to %lx (or %lu). %px is preferred because it is more uniquely
+grep'able. If in the future we need to modify the way the kernel handles
+printing pointers we will be better equipped to find the call sites.
+
+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 address 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 address 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
+
+A few examples show how the conversion would be done (excluding 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 :c:func:`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 then 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 small buffers (up to 64 bytes long) as a hex string with a
+certain separator. For larger buffers consider using
+:c:func:`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 notation - and big endian order in lower (b)
+or upper case (B) hex notation.
+
+Where no additional specifiers are used the default big endian
+order with lower case hex notation will be printed.
+
+Passed by reference.
+
+dentry names
+------------
+
+::
+
+ %pd{,2,3,4}
+ %pD{,2,3,4}
+
+For printing dentry name; if we race with :c:func:`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.
+
+block_device names
+------------------
+
+::
+
+ %pg sda, sda1 or loop0p1
+
+For printing name of block_device pointers.
+
+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;
+ };
+
+Implements a "recursive vsnprintf".
+
+Do not use this feature without some mechanism to verify the
+correctness of the format string and va_list arguments.
+
+Passed by reference.
+
+kobjects
+--------
+
+::
+
+ %pOF[fnpPcCF]
+
+
+For printing kobject based structs (device nodes). Default behaviour is
+equivalent to %pOFf.
+
+ - f - device node full_name
+ - n - device node name
+ - p - device node phandle
+ - P - device node path spec (name + @unit)
+ - F - device node flags
+ - c - major compatible string
+ - C - full compatible string
+
+The separator when using multiple arguments is ':'
+
+Examples::
+
+ %pOF /foo/bar@0 - Node full name
+ %pOFf /foo/bar@0 - Same as above
+ %pOFfp /foo/bar@0:10 - Node full name + phandle
+ %pOFfcF /foo/bar@0:foo,device:--P- - Node full name +
+ major compatible string +
+ node flags
+ D - dynamic
+ d - detached
+ P - Populated
+ B - Populated bus
+
+Passed by reference.
+
+struct clk
+----------
+
+::
+
+ %pC pll1
+ %pCn pll1
+ %pCr 1560000000
+
+For printing struct clk structures. %pC and %pCn print the name
+(Common Clock Framework) or address (legacy clock framework) of the
+structure; %pCr prints the current clock rate.
+
+Passed by reference.
+
+bitmap and its derivatives such as cpumask and nodemask
+-------------------------------------------------------
+
+::
+
+ %*pb 0779
+ %*pbl 0,3-6,8-10
+
+For printing bitmap and its derivatives such as cpumask and nodemask,
+%*pb outputs the bitmap with field width as the number of bits and %*pbl
+output the bitmap as range list with field width as the number of bits.
+
+Passed by reference.
+
+Flags bitfields such as page flags, gfp_flags
+---------------------------------------------
+
+::
+
+ %pGp referenced|uptodate|lru|active|private
+ %pGg GFP_USER|GFP_DMA32|GFP_NOWARN
+ %pGv read|exec|mayread|maywrite|mayexec|denywrite
+
+For printing flags bitfields as a collection of symbolic constants that
+would construct the value. The type of flags is given by the third
+character. Currently supported are [p]age flags, [v]ma_flags (both
+expect ``unsigned long *``) and [g]fp_flags (expects ``gfp_t *``). The flag
+names and print order depends on the particular type.
+
+Note that this format should not be used directly in the
+:c:func:`TP_printk()` part of a tracepoint. Instead, use the show_*_flags()
+functions from <trace/events/mmflags.h>.
+
+Passed by reference.
+
+Network device features
+-----------------------
+
+::
+
+ %pNF 0x000000000000c000
+
+For printing netdev_features_t.
+
+Passed by reference.
+
+Thanks
+======
+
+If you add other %p extensions, please extend <lib/test_printf.c> with
+one or more test cases, if at all feasible.
+
+Thank you for your cooperation and attention.
+++ /dev/null
-=========================================
-How to get printk format specifiers right
-=========================================
-
-:Author: Randy Dunlap <rdunlap@infradead.org>
-:Author: Andrew Murray <amurray@mpc-data.co.uk>
-
-Integer types
-=============
-
-::
-
- 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
- s32 %d or %x
- u32 %u or %x
- s64 %lld or %llx
- u64 %llu or %llx
-
-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``.
-
-The kernel's printf does not support ``%n``. For obvious reasons, floating
-point formats (``%e, %f, %g, %a``) are also not recognized. Use of any
-unsupported specifier or length qualifier results in a WARN and early
-return from vsnprintf.
-
-Raw pointer value SHOULD be printed with %p. The kernel supports
-the following extended format specifiers for pointer types:
-
-Pointer Types
-=============
-
-Pointers printed without a specifier extension (i.e unadorned %p) are
-hashed to give a unique identifier without leaking kernel addresses to user
-space. On 64 bit machines the first 32 bits are zeroed. If you _really_
-want the address see %px below.
-
-::
-
- %p abcdef12 or 00000000abcdef12
-
-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
-
-The ``F`` and ``f`` specifiers are for printing function pointers,
-for example, f->func, &gettimeofday. They have the same result as
-``S`` and ``s`` specifiers. But they do an extra conversion on
-ia64, ppc64 and parisc64 architectures where the function pointers
-are actually function descriptors.
-
-The ``S`` and ``s`` specifiers can be used for printing symbols
-from direct addresses, for example, __builtin_return_address(0),
-(void *)regs->ip. They result in the symbol name with (``S``) or
-without (``s``) offsets. If KALLSYMS are disabled then 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.
-
-Examples::
-
- printk("Going to call: %pF\n", gettimeofday);
- printk("Going to call: %pF\n", p->func);
- printk("%s: called from %pS\n", __func__, (void *)_RET_IP_);
- printk("%s: called from %pS\n", __func__,
- (void *)__builtin_return_address(0));
- printk("Faulted at %pS\n", (void *)regs->ip);
- printk(" %s%pB\n", (reliable ? "" : "? "), (void *)*stack);
-
-Kernel Pointers
-===============
-
-::
-
- %pK 01234567 or 0123456789abcdef
-
-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.
-
-Unmodified Addresses
-====================
-
-::
-
- %px 01234567 or 0123456789abcdef
-
-For printing pointers when you _really_ want to print the address. Please
-consider whether or not you are leaking sensitive information about the
-Kernel layout in memory before printing pointers with %px. %px is
-functionally equivalent to %lx. %px is preferred to %lx because it is more
-uniquely grep'able. If, in the future, we need to modify the way the Kernel
-handles printing pointers it will be nice to be able to find the call
-sites.
-
-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 :c:func:`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
-:c:func:`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 big 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 :c:func:`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.
-
-block_device names
-==================
-
-::
-
- %pg sda, sda1 or loop0p1
-
-For printing name of block_device pointers.
-
-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;
- };
-
-Implements a "recursive vsnprintf".
-
-Do not use this feature without some mechanism to verify the
-correctness of the format string and va_list arguments.
-
-Passed by reference.
-
-kobjects
-========
-
-::
-
- %pO
-
- Base specifier for kobject based structs. Must be followed with
- character for specific type of kobject as listed below:
-
- Device tree nodes:
-
- %pOF[fnpPcCF]
-
- For printing device tree nodes. The optional arguments are:
- f device node full_name
- n device node name
- p device node phandle
- P device node path spec (name + @unit)
- F device node flags
- c major compatible string
- C full compatible string
- Without any arguments prints full_name (same as %pOFf)
- The separator when using multiple arguments is ':'
-
- Examples:
-
- %pOF /foo/bar@0 - Node full name
- %pOFf /foo/bar@0 - Same as above
- %pOFfp /foo/bar@0:10 - Node full name + phandle
- %pOFfcF /foo/bar@0:foo,device:--P- - Node full name +
- major compatible string +
- node flags
- D - dynamic
- d - detached
- P - Populated
- B - Populated bus
-
- Passed by reference.
-
-
-struct clk
-==========
-
-::
-
- %pC pll1
- %pCn pll1
- %pCr 1560000000
-
-For printing struct clk structures. ``%pC`` and ``%pCn`` print the name
-(Common Clock Framework) or address (legacy clock framework) of the
-structure; ``%pCr`` prints the current clock rate.
-
-Passed by reference.
-
-bitmap and its derivatives such as cpumask and nodemask
-=======================================================
-
-::
-
- %*pb 0779
- %*pbl 0,3-6,8-10
-
-For printing bitmap and its derivatives such as cpumask and nodemask,
-``%*pb`` output the bitmap with field width as the number of bits and ``%*pbl``
-output the bitmap as range list with field width as the number of bits.
-
-Passed by reference.
-
-Flags bitfields such as page flags, gfp_flags
-=============================================
-
-::
-
- %pGp referenced|uptodate|lru|active|private
- %pGg GFP_USER|GFP_DMA32|GFP_NOWARN
- %pGv read|exec|mayread|maywrite|mayexec|denywrite
-
-For printing flags bitfields as a collection of symbolic constants that
-would construct the value. The type of flags is given by the third
-character. Currently supported are [p]age flags, [v]ma_flags (both
-expect ``unsigned long *``) and [g]fp_flags (expects ``gfp_t *``). The flag
-names and print order depends on the particular type.
-
-Note that this format should not be used directly in :c:func:`TP_printk()` part
-of a tracepoint. Instead, use the ``show_*_flags()`` functions from
-<trace/events/mmflags.h>.
-
-Passed by reference.
-
-Network device features
-=======================
-
-::
-
- %pNF 0x000000000000c000
-
-For printing netdev_features_t.
-
-Passed by reference.
-
-If you add other ``%p`` extensions, please extend lib/test_printf.c with
-one or more test cases, if at all feasible.
-
-
-Thank you for your cooperation and attention.
*
* - 'x' For printing the address. Equivalent to "%lx".
*
- * ** Please update also Documentation/printk-formats.txt when making changes **
+ * ** When making changes please also update:
+ * Documentation/core-api/printk-formats.rst
*
* Note: The difference between 'S' and 'F' is that on ia64 and ppc64
* function pointers are really function descriptors, which contain a
projects / openwrt / staging / blogic.git / commitdiff