diff options
Diffstat (limited to 'Documentation/core-api/printk-formats.rst')
| -rw-r--r-- | Documentation/core-api/printk-formats.rst | 108 |
1 files changed, 90 insertions, 18 deletions
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index d941717a191b..c0b1b6089307 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -15,9 +15,10 @@ Integer types If variable is of Type, use printk format specifier: ------------------------------------------------------------ - char %d or %x + signed char %d or %hhx unsigned char %u or %x - short int %d or %x + char %u or %x + short int %d or %hx unsigned short int %u or %x int %d or %x unsigned int %u or %x @@ -27,9 +28,9 @@ Integer types unsigned long long %llu or %llx size_t %zu or %zx ssize_t %zd or %zx - s8 %d or %x + s8 %d or %hhx u8 %u or %x - s16 %d or %x + s16 %d or %hx u16 %u or %x s32 %d or %x u32 %u or %x @@ -130,6 +131,7 @@ printed after the symbol name with an extra ``b`` appended to the end of the specifier. :: + %pS versatile_init+0x0/0x110 [module_name] %pSb versatile_init+0x0/0x110 [module_name ed5019fdf5e53be37cb1ba7899292d7e143b259e] %pSRb versatile_init+0x9/0x110 [module_name ed5019fdf5e53be37cb1ba7899292d7e143b259e] @@ -207,12 +209,17 @@ Struct Resources :: %pr [mem 0x60000000-0x6fffffff flags 0x2200] or + [mem 0x60000000 flags 0x2200] or [mem 0x0000000060000000-0x000000006fffffff flags 0x2200] + [mem 0x0000000060000000 flags 0x2200] %pR [mem 0x60000000-0x6fffffff pref] or + [mem 0x60000000 pref] or [mem 0x0000000060000000-0x000000006fffffff pref] + [mem 0x0000000060000000 pref] For printing struct resources. The ``R`` and ``r`` specifiers result in a -printed resource with (R) or without (r) a decoded flags member. +printed resource with (R) or without (r) a decoded flags member. If start is +equal to end only print the start value. Passed by reference. @@ -229,6 +236,19 @@ width of the CPU data path. Passed by reference. +Struct Range +------------ + +:: + + %pra [range 0x0000000060000000-0x000000006fffffff] or + [range 0x0000000060000000] + +For printing struct range. struct range holds an arbitrary range of u64 +values. If start is equal to end only print the start value. + +Passed by reference. + DMA address types dma_addr_t ---------------------------- @@ -501,7 +521,7 @@ Fwnode handles %pfw[fP] -For printing information on fwnode handles. The default is to print the full +For printing information on an fwnode_handle. The default is to print the full node name, including the path. The modifiers are functionally equivalent to %pOF above. @@ -527,11 +547,13 @@ Time and date %pt[RT]s YYYY-mm-dd HH:MM:SS %pt[RT]d YYYY-mm-dd %pt[RT]t HH:MM:SS - %pt[RT][dt][r][s] + %ptSp <seconds>.<nanoseconds> + %pt[RST][dt][r][s] For printing date and time as represented by:: - R struct rtc_time structure + R content of struct rtc_time + S content of struct timespec64 T time64_t type in human readable format. @@ -543,6 +565,11 @@ The %pt[RT]s (space) will override ISO 8601 separator by using ' ' (space) instead of 'T' (Capital T) between date and time. It won't have any effect when date or time is omitted. +The %ptSp is equivalent to %lld.%09ld for the content of the struct timespec64. +When the other specifiers are given, it becomes the respective equivalent of +%ptT[dt][r][s].%09ld. In other words, the seconds are being printed in +the human readable format followed by a dot and nanoseconds. + Passed by reference. struct clk @@ -551,9 +578,8 @@ struct clk :: %pC pll1 - %pCn pll1 -For printing struct clk structures. %pC and %pCn print the name of the clock +For printing struct clk structures. %pC prints the name of the clock (Common Clock Framework) or a unique 32-bit ID (legacy clock framework). Passed by reference. @@ -574,20 +600,24 @@ The field width is passed by value, the bitmap is passed by reference. Helper macros cpumask_pr_args() and nodemask_pr_args() are available to ease printing cpumask and nodemask. -Flags bitfields such as page flags, gfp_flags ---------------------------------------------- +Flags bitfields such as page flags and gfp_flags +-------------------------------------------------------- :: - %pGp referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff + %pGp 0x17ffffc0002036(referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff) %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. +character. Currently supported are: + + - p - [p]age flags, expects value of type (``unsigned long *``) + - v - [v]ma_flags, expects value of type (``unsigned long *``) + - g - [g]fp_flags, expects value of type (``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() @@ -624,10 +654,52 @@ Examples:: %p4cc Y10 little-endian (0x20303159) %p4cc NV12 big-endian (0xb231564e) +Generic FourCC code +------------------- + +:: + %p4c[h[R]lb] gP00 (0x67503030) + +Print a generic FourCC code, as both ASCII characters and its numerical +value as hexadecimal. + +The generic FourCC code is always printed in the big-endian format, +the most significant byte first. This is the opposite of V4L/DRM FourCCs. + +The additional ``h``, ``hR``, ``l``, and ``b`` specifiers define what +endianness is used to load the stored bytes. The data might be interpreted +using the host, reversed host byte order, little-endian, or big-endian. + +Passed by reference. + +Examples for a little-endian machine, given &(u32)0x67503030:: + + %p4ch gP00 (0x67503030) + %p4chR 00Pg (0x30305067) + %p4cl gP00 (0x67503030) + %p4cb 00Pg (0x30305067) + +Examples for a big-endian machine, given &(u32)0x67503030:: + + %p4ch gP00 (0x67503030) + %p4chR 00Pg (0x30305067) + %p4cl 00Pg (0x30305067) + %p4cb gP00 (0x67503030) + +Rust +---- + +:: + + %pA + +Only intended to be used from Rust code to format ``core::fmt::Arguments``. +Do *not* use it from C. + Thanks ====== -If you add other %p extensions, please extend <lib/test_printf.c> with -one or more test cases, if at all feasible. +If you add other %p extensions, please extend <lib/tests/printf_kunit.c> +with one or more test cases, if at all feasible. Thank you for your cooperation and attention. |