Documentation/printk-formats.txt is a candidate for conversion to
ReStructuredText format. Some effort has already been made to do this
conversion even thought the suffix is currently .txt
Changes required to complete conversion
- Add double backticks where needed.
- Add entry to Documentation/index.rst
- Use flat-table instead of ASCII table.
- Fix minor grammatical errors.
- Capitalize headers and correctly order heading adornments.
- Use 'Passed by reference' uniformly.
- Update pointer documentation around %px specifier.
- Fix erroneous double backticks (to commas).
- Simplify documentation for kobject.
- Convert lib/vsnprintf.c function docs to use kernel-docs and
include in Documentation/printk-formats.rst
Signed-off-by: Tobin C. Harding <me@xxxxxxxx>
---
The last two need special reviewing please. In particular the conversion
of kernel-docs in vsnprintf.c attempt was made to reduce documentation
duplication with comments in the source code being simplified in order
to be suitable for inclusion in Documentation/printk-formats.rst
I used -M when formatting the patch. If you don't like the diff with
this flag just holla.
thanks,
Tobin.
Documentation/index.rst | 10 +
.../{printk-formats.txt => printk-formats.rst} | 295 ++++++++++++---------
lib/vsprintf.c | 160 +++++------
3 files changed, 235 insertions(+), 230 deletions(-)
rename Documentation/{printk-formats.txt => printk-formats.rst} (61%)
diff --git a/Documentation/index.rst b/Documentation/index.rst
index cb7f1ba5b3b1..83ace60efbe7 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -87,6 +87,16 @@ implementation.
sh/index
+Miscellaneous documentation
+---------------------------
+
+These guides contain general information useful when writing kernel code.
+
+.. toctree::
+ :maxdepth: 1
+
+ printk-formats
+
Korean translations
-------------------
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.rst
similarity index 61%
rename from Documentation/printk-formats.txt
rename to Documentation/printk-formats.rst
index aa0a776c817a..51449d213748 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.rst
@@ -1,6 +1,6 @@
-=========================================
-How to get printk format specifiers right
-=========================================
+=============================================
+How to Get ``printk`` Format Specifiers Right
+=============================================
:Author: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
:Author: Andrew Murray <amurray@xxxxxxxxxxxxxx>
@@ -8,56 +8,91 @@ How to get printk format specifiers right
Integer types
=============
-::
+For printing integer types, we have the following format specifiers:
+
+ .. flat-table::
+ :widths: 2 2
+
+ * - **Type**
+ - **Specifier**
+
+ * - ``int``
+ - ``%d`` or ``%x``
+
+ * - ``unsigned int``
+ - ``%u`` or ``%x``
+
+ * - ``long``
+ - ``%ld`` or ``%lx``
+
+ * - ``unsigned long``
+ - ``%lu`` or ``%lx``
+
+ * - ``long long``
+ - ``%lld`` or ``%llx``
- 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``,
+ * - ``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);
+ printk("test: total blocks: %llu\n", (unsigned long long)blockcount);
-Reminder: ``sizeof()`` result is of type ``size_t``.
+Reminder: ``sizeof()`` returns type ``size_t``.
-The kernel's printf does not support ``%n``. For obvious reasons, floating
+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:
+return from ``vsnprintf()``.
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.
+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.
+
+.. kernel-doc:: lib/vsprintf.c
+ :doc: Extended Format Pointer Specifiers
+
+
+Plain Pointers
+--------------
::
%p abcdef12 or 00000000abcdef12
+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.
+
Symbols/Function Pointers
-=========================
+-------------------------
::
@@ -69,61 +104,60 @@ Symbols/Function Pointers
%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 ``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
+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.
+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("%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.
+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
+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.
+kernel memory layout before printing pointers with ``%px``. ``%px`` is
+functionally equivalent to ``%lx`` (or ``%lu``). ``%px``, however, is
+preferable 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
-================
+----------------
::
@@ -132,12 +166,13 @@ Struct Resources
%pR [mem 0x60000000-0x6fffffff pref] or
[mem 0x0000000060000000-0x000000006fffffff pref]
-For printing struct resources. The ``R`` and ``r`` specifiers result in a
+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``
-========================================
+Physical Address Types ``phys_addr_t``
+--------------------------------------
::
@@ -145,20 +180,24 @@ Physical addresses types ``phys_addr_t``
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.
+the width of the CPU data path.
+
+Passed by reference.
-DMA addresses types ``dma_addr_t``
-==================================
+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.
+regardless of the width of the CPU data path.
-Raw buffer as an escaped string
-===============================
+Passed by reference.
+
+Raw Buffer as an Escaped String
+-------------------------------
::
@@ -168,7 +207,7 @@ 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
+A few examples show how the conversion would be done (the result string
without surrounding quotes)::
%*pE "\eb \C\a"\220\r]"
@@ -194,8 +233,8 @@ printing SSIDs.
If field width is omitted the 1 byte only will be escaped.
-Raw buffer as a hex string
-==========================
+Raw Buffer as a Hex String
+--------------------------
::
@@ -205,11 +244,11 @@ Raw buffer as a hex string
%*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
+certain separator. For the larger buffers consider using
:c:func:`print_hex_dump`.
-MAC/FDDI addresses
-==================
+MAC/FDDI Addresses
+------------------
::
@@ -233,8 +272,8 @@ of Bluetooth addresses which are in the little endian order.
Passed by reference.
-IPv4 addresses
-==============
+IPv4 Addresses
+--------------
::
@@ -252,8 +291,8 @@ no specifier is provided the default network/big endian order is used.
Passed by reference.
-IPv6 addresses
-==============
+IPv6 Addresses
+--------------
::
@@ -271,8 +310,8 @@ http://tools.ietf.org/html/rfc5952
Passed by reference.
-IPv4/IPv6 addresses (generic, with port, flowinfo, scope)
-=========================================================
+IPv4/IPv6 Addresses (generic, with port, flowinfo or scope)
+---------------------------------------------------------------
::
@@ -282,8 +321,8 @@ IPv4/IPv6 addresses (generic, with port, flowinfo, scope)
%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``,
+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
@@ -308,8 +347,8 @@ Further examples::
%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
-===================
+UUID/GUID Addresses
+-------------------
::
@@ -318,18 +357,18 @@ UUID/GUID addresses
%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.
+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 digits - and big endian order
+in lower (``b``) or upper case (``B``) hex digits.
Where no additional specifiers are used the default big endian
-order with lower case hex characters will be printed.
+order with lower case hex digits will be printed.
Passed by reference.
-dentry names
-============
+Dentry Names
+------------
::
@@ -343,24 +382,24 @@ equivalent of ``%s`` ``dentry->d_name.name`` we used to use, ``%pd<n>`` prints
Passed by reference.
-block_device names
-==================
+block_device Names
+------------------
::
%pg sda, sda1 or loop0p1
-For printing name of block_device pointers.
+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::
+For printing ``struct va_format`` structures. These contain a format string
+and ``va_list`` as follows::
struct va_format {
const char *fmt;
@@ -370,36 +409,33 @@ and va_list as follows::
Implements a "recursive vsnprintf".
Do not use this feature without some mechanism to verify the
-correctness of the format string and va_list arguments.
+correctness of the format string and ``va_list`` arguments.
Passed by reference.
kobjects
-========
-
+--------
+
::
- %pO
+ %pOF[fnpPcCF]
- Base specifier for kobject based structs. Must be followed with
- character for specific type of kobject as listed below:
- Device tree nodes:
+For printing kobject based structs (device nodes). Default behaviour is
+equivalent to ``%pOFf``.
- %pOF[fnpPcCF]
+ - ``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
- 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 ':'
+The separator when using multiple arguments is ``:``
- Examples:
+Examples:
+::
%pOF /foo/bar@0 - Node full name
%pOFf /foo/bar@0 - Same as above
@@ -412,11 +448,10 @@ kobjects
P - Populated
B - Populated bus
- Passed by reference.
-
+Passed by reference.
struct clk
-==========
+----------
::
@@ -424,14 +459,14 @@ struct clk
%pCn pll1
%pCr 1560000000
-For printing struct clk structures. ``%pC`` and ``%pCn`` print the name
+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
-=======================================================
+Bitmap and its Derivatives (such as cpumask and nodemask)
+---------------------------------------------------------
::
@@ -439,13 +474,13 @@ bitmap and its derivatives such as cpumask and nodemask
%*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.
+``%*pb`` outputs the bitmap with field width as the number of bits and ``%*pbl``
+outputs the bitmap as range list with field width as the number of bits.
Passed by reference.
-Flags bitfields such as page flags, gfp_flags
-=============================================
+Flags Bitfields (such as page flags, gfp_flags)
+-----------------------------------------------
::
@@ -459,25 +494,27 @@ 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>.
+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
-=======================
+Network Device Features
+-----------------------
::
%pNF 0x000000000000c000
-For printing netdev_features_t.
+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.
+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.
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 01c3957b2de6..f9247b78e8ef 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1727,115 +1727,73 @@ static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
return number(buf, end, hashval, spec);
}
+/**
+ * DOC: Extended Format Pointer Specifiers
+ *
+ * Briefly we handle the following extensions:
+ *
+ * - ``F`` - For symbolic function descriptor pointers with offset.
+ * - ``f`` - For simple symbolic function names without offset.
+ *
+ * - ``S`` - For symbolic direct pointers with offset.
+ * - ``s`` - For symbolic direct pointers without offset.
+ * - ``[FfSs]R`` - As above with ``__builtin_extract_return_addr()`` translation.
+ * - ``B`` - For backtraced symbolic direct pointers with offset.
+ * - ``R`` - For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref].
+ * - ``r`` - For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201].
+ * - ``b[l]`` - For a bitmap, the number of bits is determined by the field
+ * width which must be explicitly specified either as part of the format
+ * string ``32b[l]`` or through ``*b[l]``, ``[l]`` selects range-list format
+ * instead of hex format.
+ * - ``M`` - For a 6-byte MAC address, it prints the address in the usual
+ * colon-separated hex notation.
+ * - ``m`` - For a 6-byte MAC address, it prints the hex address without colons.
+ * - ``MF`` - For a 6-byte MAC FDDI address, it prints the address with a
+ * dash-separated hex notation.
+ * - ``[mM]R`` - For a 6-byte MAC address, Reverse order (Bluetooth).
+ * - ``I[46]`` - For IPv4/IPv6 addresses printed in the usual way.
+ * - ``I[S][pfs]`` - For generic IPv4/IPv6 address (struct sockaddr *) that falls
+ * back to ``[4]`` or ``[6]`` and is able to print port ``[p]``,
+ * flowinfo ``[f]``, scope ``[s]``.
+ * - ``i[46]`` - For 'raw' IPv4/IPv6 addresses IPv6 omits the colons (01020304...0f)
+ * IPv4 uses dot-separated decimal with leading 0's (010.123.045.006).
+ * - ``i[S][pfs]`` - For generic IPv4/IPv6 address (struct sockaddr *) that falls back
+ * to ``[4]`` or ``[6]`` (``[pfs]`` as above).
+ * - ``[Ii][4S][hnbl]`` - For IPv4 addresses in host, network, big or little endian order.
+ * - ``I[6S]c`` - For IPv6 addresses printed as per http://tools.ietf.org/html/rfc5952.
+ * - ``E[achnops]`` - For an escaped buffer.
+ * - ``U`` - For a 16 byte UUID/GUID.
+ * - ``V`` - For a ``struct va_format`` which contains a format ``string *``
+ * and ``va_list *``.
+ * - ``K`` - For a kernel pointer that should be hidden from unprivileged users.
+ * - ``NF`` - For a ``netdev_features_t``.
+ * - ``h[CDN]`` - For a variable-length buffer.
+ * - ``a[pd]`` - For address types ``[p] phys_addr_t``, ``[d] dma_addr_t`` and
+ * derivatives.
+ * - ``d[234]`` - For a dentry name (optionally 2-4 last components).
+ * - ``D[234]`` - Same as 'd' but for a struct file.
+ * - ``g`` - For ``block_device`` name (gendisk + partition number).
+ * - ``C[n]`` - For a clock, it prints the name (Common Clock Framework) or
+ * address (legacy clock framework) of the clock. ``[n]`` is optional.
+ * - ``Cr`` - For a clock, it prints the current rate of the clock.
+ * - ``G`` - For flags to be printed as a collection of symbolic strings that
+ * would construct the specific value.
+ * - ``O`` - For a kobject based struct (device node).
+ * - ``x`` - For printing the address. Equivalent to ``%lx``.
+ */
+
/*
* Show a '%p' thing. A kernel extension is that the '%p' is followed
* by an extra set of alphanumeric characters that are extended format
* specifiers.
*
+ * Please see Documentation/printk-formats.rst for fuller description
+ * of specifier extensions. Also please update this file when making
+ * changes.
+ *
* Please update scripts/checkpatch.pl when adding/removing conversion
* characters. (Search for "check for vsprintf extension").
*
- * Right now we handle:
- *
- * - 'F' For symbolic function descriptor pointers with offset
- * - 'f' For simple symbolic function names without offset
- * - 'S' For symbolic direct pointers with offset
- * - 's' For symbolic direct pointers without offset
- * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
- * - 'B' For backtraced symbolic direct pointers with offset
- * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
- * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
- * - 'b[l]' For a bitmap, the number of bits is determined by the field
- * width which must be explicitly specified either as part of the
- * format string '%32b[l]' or through '%*b[l]', [l] selects
- * range-list format instead of hex format
- * - 'M' For a 6-byte MAC address, it prints the address in the
- * usual colon-separated hex notation
- * - 'm' For a 6-byte MAC address, it prints the hex address without colons
- * - 'MF' For a 6-byte MAC FDDI address, it prints the address
- * with a dash-separated hex notation
- * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
- * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
- * IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
- * IPv6 uses colon separated network-order 16 bit hex with leading 0's
- * [S][pfs]
- * Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
- * [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
- * - 'i' [46] for 'raw' IPv4/IPv6 addresses
- * IPv6 omits the colons (01020304...0f)
- * IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
- * [S][pfs]
- * Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
- * [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
- * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
- * - 'I[6S]c' for IPv6 addresses printed as specified by
- * http://tools.ietf.org/html/rfc5952
- * - 'E[achnops]' For an escaped buffer, where rules are defined by combination
- * of the following flags (see string_escape_mem() 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.
- * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
- * "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
- * Options for %pU are:
- * b big endian lower case hex (default)
- * B big endian UPPER case hex
- * l little endian lower case hex
- * L little endian UPPER case hex
- * big endian output byte order is:
- * [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
- * little endian output byte order is:
- * [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
- * - 'V' For a struct va_format which contains a format string * and va_list *,
- * call vsnprintf(->format, *->va_list).
- * Implements a "recursive vsnprintf".
- * Do not use this feature without some mechanism to verify the
- * correctness of the format string and va_list arguments.
- * - 'K' For a kernel pointer that should be hidden from unprivileged users
- * - 'NF' For a netdev_features_t
- * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
- * a certain separator (' ' by default):
- * C colon
- * D dash
- * N no separator
- * The maximum supported length is 64 bytes of the input. Consider
- * to use print_hex_dump() for the larger input.
- * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
- * (default assumed to be phys_addr_t, passed by reference)
- * - 'd[234]' For a dentry name (optionally 2-4 last components)
- * - 'D[234]' Same as 'd' but for a struct file
- * - 'g' For block_device name (gendisk + partition number)
- * - 'C' For a clock, it prints the name (Common Clock Framework) or address
- * (legacy clock framework) of the clock
- * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
- * (legacy clock framework) of the clock
- * - 'Cr' For a clock, it prints the current rate of the clock
- * - 'G' For flags to be printed as a collection of symbolic strings that would
- * construct the specific value. Supported flags given by option:
- * p page flags (see struct page) given as pointer to unsigned long
- * g gfp flags (GFP_* and __GFP_*) given as pointer to gfp_t
- * v vma flags (VM_*) given as pointer to unsigned long
- * - 'O' For a kobject based struct. Must be one of the following:
- * - 'OF[fnpPcCF]' For a device tree object
- * Without any optional arguments prints the full_name
- * 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
- *
- * - 'x' For printing the address. Equivalent to "%lx".
- *
- * ** Please update also Documentation/printk-formats.txt when making changes **
- *
* Note: The difference between 'S' and 'F' is that on ia64 and ppc64
* function pointers are really function descriptors, which contain a
* pointer to the real address.
--
2.7.4
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