Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752625AbdLFSSy (ORCPT ); Wed, 6 Dec 2017 13:18:54 -0500 Received: from merlin.infradead.org ([205.233.59.134]:57820 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752317AbdLFSSv (ORCPT ); Wed, 6 Dec 2017 13:18:51 -0500 Subject: Re: [PATCH] doc: convert printk-formats.txt to rst To: "Tobin C. Harding" , Jonathan Corbet Cc: Andrew Murray , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org References: <1512524729-16051-1-git-send-email-me@tobin.cc> From: Randy Dunlap Message-ID: Date: Wed, 6 Dec 2017 10:18:49 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1512524729-16051-1-git-send-email-me@tobin.cc> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 30176 Lines: 801 On 12/05/2017 05:45 PM, Tobin C. Harding wrote: > 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. That's a style choice and an unneeded change (referring to Capitalize headers). > - 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 good idea. > > Signed-off-by: Tobin C. Harding > --- > > 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/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 > :Author: Andrew Murray > @@ -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 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 ```` 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* 64-bit > +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. then I think... > > -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) > +--------------------------------------------------------------- I prefer the additional (Oxford) comma. and why is the --- line longer than the header? > > :: > > @@ -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. digits could imply base 10. but no big deal. > > Passed by reference. > > -dentry names > -============ > +Dentry Names > +------------ > > :: > > @@ -343,24 +382,24 @@ equivalent of ``%s`` ``dentry->d_name.name`` we used to use, ``%pd`` 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 > -. > +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 ````. > > 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 "this file" is the file that I am reading? or could it be "that file"? > + * 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. > ta. -- ~Randy