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diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt deleted file mode 100644 index aa0a776c817a..000000000000 --- a/Documentation/printk-formats.txt +++ /dev/null @@ -1,483 +0,0 @@ -========================================= -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. |