19cfe06f8SSteven Rostedt /* 29cfe06f8SSteven Rostedt * If TRACE_SYSTEM is defined, that will be the directory created 34e20e3a6SSteven Rostedt (Red Hat) * in the ftrace directory under /sys/kernel/tracing/events/<system> 49cfe06f8SSteven Rostedt * 544ad18e0SSteven Rostedt * The define_trace.h below will also look for a file name of 69cfe06f8SSteven Rostedt * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here. 744ad18e0SSteven Rostedt * In this case, it would look for sample.h 89cfe06f8SSteven Rostedt * 944ad18e0SSteven Rostedt * If the header name will be different than the system name 1044ad18e0SSteven Rostedt * (as in this case), then you can override the header name that 1144ad18e0SSteven Rostedt * define_trace.h will look up by defining TRACE_INCLUDE_FILE 129cfe06f8SSteven Rostedt * 1344ad18e0SSteven Rostedt * This file is called trace-events-sample.h but we want the system 1444ad18e0SSteven Rostedt * to be called "sample". Therefore we must define the name of this 1544ad18e0SSteven Rostedt * file: 169cfe06f8SSteven Rostedt * 1744ad18e0SSteven Rostedt * #define TRACE_INCLUDE_FILE trace-events-sample 189cfe06f8SSteven Rostedt * 1944ad18e0SSteven Rostedt * As we do an the bottom of this file. 20d0b6e04aSLi Zefan * 21d0b6e04aSLi Zefan * Notice that TRACE_SYSTEM should be defined outside of #if 22d0b6e04aSLi Zefan * protection, just like TRACE_INCLUDE_FILE. 239cfe06f8SSteven Rostedt */ 249cfe06f8SSteven Rostedt #undef TRACE_SYSTEM 2571e1c8acSSteven Rostedt #define TRACE_SYSTEM sample 269cfe06f8SSteven Rostedt 279cfe06f8SSteven Rostedt /* 28d0b6e04aSLi Zefan * Notice that this file is not protected like a normal header. 29d0b6e04aSLi Zefan * We also must allow for rereading of this file. The 30d0b6e04aSLi Zefan * 31d0b6e04aSLi Zefan * || defined(TRACE_HEADER_MULTI_READ) 32d0b6e04aSLi Zefan * 33d0b6e04aSLi Zefan * serves this purpose. 34d0b6e04aSLi Zefan */ 35d0b6e04aSLi Zefan #if !defined(_TRACE_EVENT_SAMPLE_H) || defined(TRACE_HEADER_MULTI_READ) 36d0b6e04aSLi Zefan #define _TRACE_EVENT_SAMPLE_H 37d0b6e04aSLi Zefan 38d0b6e04aSLi Zefan /* 39d0b6e04aSLi Zefan * All trace headers should include tracepoint.h, until we finally 40d0b6e04aSLi Zefan * make it into a standard header. 41d0b6e04aSLi Zefan */ 42d0b6e04aSLi Zefan #include <linux/tracepoint.h> 43d0b6e04aSLi Zefan 44d0b6e04aSLi Zefan /* 459cfe06f8SSteven Rostedt * The TRACE_EVENT macro is broken up into 5 parts. 469cfe06f8SSteven Rostedt * 479cfe06f8SSteven Rostedt * name: name of the trace point. This is also how to enable the tracepoint. 489cfe06f8SSteven Rostedt * A function called trace_foo_bar() will be created. 499cfe06f8SSteven Rostedt * 509cfe06f8SSteven Rostedt * proto: the prototype of the function trace_foo_bar() 519cfe06f8SSteven Rostedt * Here it is trace_foo_bar(char *foo, int bar). 529cfe06f8SSteven Rostedt * 539cfe06f8SSteven Rostedt * args: must match the arguments in the prototype. 549cfe06f8SSteven Rostedt * Here it is simply "foo, bar". 559cfe06f8SSteven Rostedt * 569cfe06f8SSteven Rostedt * struct: This defines the way the data will be stored in the ring buffer. 574e20e3a6SSteven Rostedt (Red Hat) * The items declared here become part of a special structure 584e20e3a6SSteven Rostedt (Red Hat) * called "__entry", which can be used in the fast_assign part of the 594e20e3a6SSteven Rostedt (Red Hat) * TRACE_EVENT macro. 609cfe06f8SSteven Rostedt * 614e20e3a6SSteven Rostedt (Red Hat) * Here are the currently defined types you can use: 624e20e3a6SSteven Rostedt (Red Hat) * 634e20e3a6SSteven Rostedt (Red Hat) * __field : Is broken up into type and name. Where type can be any 644e20e3a6SSteven Rostedt (Red Hat) * primitive type (integer, long or pointer). 654e20e3a6SSteven Rostedt (Red Hat) * 664e20e3a6SSteven Rostedt (Red Hat) * __field(int, foo) 674e20e3a6SSteven Rostedt (Red Hat) * 684e20e3a6SSteven Rostedt (Red Hat) * __entry->foo = 5; 694e20e3a6SSteven Rostedt (Red Hat) * 704e20e3a6SSteven Rostedt (Red Hat) * __field_struct : This can be any static complex data type (struct, union 714e20e3a6SSteven Rostedt (Red Hat) * but not an array). Be careful using complex types, as each 724e20e3a6SSteven Rostedt (Red Hat) * event is limited in size, and copying large amounts of data 734e20e3a6SSteven Rostedt (Red Hat) * into the ring buffer can slow things down. 744e20e3a6SSteven Rostedt (Red Hat) * 754e20e3a6SSteven Rostedt (Red Hat) * __field_struct(struct bar, foo) 764e20e3a6SSteven Rostedt (Red Hat) * 774e20e3a6SSteven Rostedt (Red Hat) * __entry->bar.x = y; 784e20e3a6SSteven Rostedt (Red Hat) 794e20e3a6SSteven Rostedt (Red Hat) * __array: There are three fields (type, name, size). The type is the 804e20e3a6SSteven Rostedt (Red Hat) * type of elements in teh array, the name is the name of the array. 814e20e3a6SSteven Rostedt (Red Hat) * size is the number of items in the array (not the total size). 824e20e3a6SSteven Rostedt (Red Hat) * 834e20e3a6SSteven Rostedt (Red Hat) * __array( char, foo, 10) is the same as saying: char foo[10]; 844e20e3a6SSteven Rostedt (Red Hat) * 854e20e3a6SSteven Rostedt (Red Hat) * Assigning arrays can be done like any array: 864e20e3a6SSteven Rostedt (Red Hat) * 874e20e3a6SSteven Rostedt (Red Hat) * __entry->foo[0] = 'a'; 884e20e3a6SSteven Rostedt (Red Hat) * 894e20e3a6SSteven Rostedt (Red Hat) * memcpy(__entry->foo, bar, 10); 904e20e3a6SSteven Rostedt (Red Hat) * 914e20e3a6SSteven Rostedt (Red Hat) * __dynamic_array: This is similar to array, but can vary is size from 924e20e3a6SSteven Rostedt (Red Hat) * instance to instance of the tracepoint being called. 934e20e3a6SSteven Rostedt (Red Hat) * Like __array, this too has three elements (type, name, size); 944e20e3a6SSteven Rostedt (Red Hat) * type is the type of the element, name is the name of the array. 954e20e3a6SSteven Rostedt (Red Hat) * The size is different than __array. It is not a static number, 964e20e3a6SSteven Rostedt (Red Hat) * but the algorithm to figure out the length of the array for the 974e20e3a6SSteven Rostedt (Red Hat) * specific instance of tracepoint. Again, size is the numebr of 984e20e3a6SSteven Rostedt (Red Hat) * items in the array, not the total length in bytes. 994e20e3a6SSteven Rostedt (Red Hat) * 1004e20e3a6SSteven Rostedt (Red Hat) * __dynamic_array( int, foo, bar) is similar to: int foo[bar]; 1014e20e3a6SSteven Rostedt (Red Hat) * 1024e20e3a6SSteven Rostedt (Red Hat) * Note, unlike arrays, you must use the __get_dynamic_array() macro 1034e20e3a6SSteven Rostedt (Red Hat) * to access the array. 1044e20e3a6SSteven Rostedt (Red Hat) * 1054e20e3a6SSteven Rostedt (Red Hat) * memcpy(__get_dynamic_array(foo), bar, 10); 1064e20e3a6SSteven Rostedt (Red Hat) * 1074e20e3a6SSteven Rostedt (Red Hat) * Notice, that "__entry" is not needed here. 1084e20e3a6SSteven Rostedt (Red Hat) * 1094e20e3a6SSteven Rostedt (Red Hat) * __string: This is a special kind of __dynamic_array. It expects to 1104e20e3a6SSteven Rostedt (Red Hat) * have a nul terminated character array passed to it (it allows 1114e20e3a6SSteven Rostedt (Red Hat) * for NULL too, which would be converted into "(null)"). __string 1124e20e3a6SSteven Rostedt (Red Hat) * takes two paramenter (name, src), where name is the name of 1134e20e3a6SSteven Rostedt (Red Hat) * the string saved, and src is the string to copy into the 1144e20e3a6SSteven Rostedt (Red Hat) * ring buffer. 1154e20e3a6SSteven Rostedt (Red Hat) * 1164e20e3a6SSteven Rostedt (Red Hat) * __string(foo, bar) is similar to: strcpy(foo, bar) 1174e20e3a6SSteven Rostedt (Red Hat) * 1184e20e3a6SSteven Rostedt (Red Hat) * To assign a string, use the helper macro __assign_str(). 1194e20e3a6SSteven Rostedt (Red Hat) * 1204e20e3a6SSteven Rostedt (Red Hat) * __assign_str(foo, bar); 1214e20e3a6SSteven Rostedt (Red Hat) * 1224e20e3a6SSteven Rostedt (Red Hat) * In most cases, the __assign_str() macro will take the same 1234e20e3a6SSteven Rostedt (Red Hat) * parameters as the __string() macro had to declare the string. 1244e20e3a6SSteven Rostedt (Red Hat) * 1254e20e3a6SSteven Rostedt (Red Hat) * __bitmask: This is another kind of __dynamic_array, but it expects 1264e20e3a6SSteven Rostedt (Red Hat) * an array of longs, and the number of bits to parse. It takes 1274e20e3a6SSteven Rostedt (Red Hat) * two parameters (name, nr_bits), where name is the name of the 1284e20e3a6SSteven Rostedt (Red Hat) * bitmask to save, and the nr_bits is the number of bits to record. 1294e20e3a6SSteven Rostedt (Red Hat) * 1304e20e3a6SSteven Rostedt (Red Hat) * __bitmask(target_cpu, nr_cpumask_bits) 1314e20e3a6SSteven Rostedt (Red Hat) * 1324e20e3a6SSteven Rostedt (Red Hat) * To assign a bitmask, use the __assign_bitmask() helper macro. 1334e20e3a6SSteven Rostedt (Red Hat) * 1344e20e3a6SSteven Rostedt (Red Hat) * __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits); 1354e20e3a6SSteven Rostedt (Red Hat) * 1369cfe06f8SSteven Rostedt * 1379cfe06f8SSteven Rostedt * fast_assign: This is a C like function that is used to store the items 1384e20e3a6SSteven Rostedt (Red Hat) * into the ring buffer. A special variable called "__entry" will be the 1394e20e3a6SSteven Rostedt (Red Hat) * structure that points into the ring buffer and has the same fields as 1404e20e3a6SSteven Rostedt (Red Hat) * described by the struct part of TRACE_EVENT above. 1419cfe06f8SSteven Rostedt * 1429cfe06f8SSteven Rostedt * printk: This is a way to print out the data in pretty print. This is 1439cfe06f8SSteven Rostedt * useful if the system crashes and you are logging via a serial line, 1449cfe06f8SSteven Rostedt * the data can be printed to the console using this "printk" method. 1454e20e3a6SSteven Rostedt (Red Hat) * This is also used to print out the data from the trace files. 1464e20e3a6SSteven Rostedt (Red Hat) * Again, the __entry macro is used to access the data from the ring buffer. 1474e20e3a6SSteven Rostedt (Red Hat) * 1484e20e3a6SSteven Rostedt (Red Hat) * Note, __dynamic_array, __string, and __bitmask require special helpers 1494e20e3a6SSteven Rostedt (Red Hat) * to access the data. 1504e20e3a6SSteven Rostedt (Red Hat) * 1514e20e3a6SSteven Rostedt (Red Hat) * For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo) 1524e20e3a6SSteven Rostedt (Red Hat) * Use __get_dynamic_array_len(foo) to get the length of the array 1534e20e3a6SSteven Rostedt (Red Hat) * saved. 1544e20e3a6SSteven Rostedt (Red Hat) * 1554e20e3a6SSteven Rostedt (Red Hat) * For __string(foo, bar) use __get_str(foo) 1564e20e3a6SSteven Rostedt (Red Hat) * 1574e20e3a6SSteven Rostedt (Red Hat) * For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus) 1584e20e3a6SSteven Rostedt (Red Hat) * 1599cfe06f8SSteven Rostedt * 1609cfe06f8SSteven Rostedt * Note, that for both the assign and the printk, __entry is the handler 1619cfe06f8SSteven Rostedt * to the data structure in the ring buffer, and is defined by the 1629cfe06f8SSteven Rostedt * TP_STRUCT__entry. 1639cfe06f8SSteven Rostedt */ 1644e20e3a6SSteven Rostedt (Red Hat) 1654e20e3a6SSteven Rostedt (Red Hat) /* 1664e20e3a6SSteven Rostedt (Red Hat) * It is OK to have helper functions in the file, but they need to be protected 1674e20e3a6SSteven Rostedt (Red Hat) * from being defined more than once. Remember, this file gets included more 1684e20e3a6SSteven Rostedt (Red Hat) * than once. 1694e20e3a6SSteven Rostedt (Red Hat) */ 1704e20e3a6SSteven Rostedt (Red Hat) #ifndef __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS 1714e20e3a6SSteven Rostedt (Red Hat) #define __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS 1724e20e3a6SSteven Rostedt (Red Hat) static inline int __length_of(const int *list) 1734e20e3a6SSteven Rostedt (Red Hat) { 1744e20e3a6SSteven Rostedt (Red Hat) int i; 1754e20e3a6SSteven Rostedt (Red Hat) 1764e20e3a6SSteven Rostedt (Red Hat) if (!list) 1774e20e3a6SSteven Rostedt (Red Hat) return 0; 1784e20e3a6SSteven Rostedt (Red Hat) 1794e20e3a6SSteven Rostedt (Red Hat) for (i = 0; list[i]; i++) 1804e20e3a6SSteven Rostedt (Red Hat) ; 1814e20e3a6SSteven Rostedt (Red Hat) return i; 1824e20e3a6SSteven Rostedt (Red Hat) } 1834e20e3a6SSteven Rostedt (Red Hat) #endif 1844e20e3a6SSteven Rostedt (Red Hat) 1859cfe06f8SSteven Rostedt TRACE_EVENT(foo_bar, 1869cfe06f8SSteven Rostedt 1874e20e3a6SSteven Rostedt (Red Hat) TP_PROTO(const char *foo, int bar, const int *lst, 1884e20e3a6SSteven Rostedt (Red Hat) const char *string, const struct cpumask *mask), 1899cfe06f8SSteven Rostedt 1904e20e3a6SSteven Rostedt (Red Hat) TP_ARGS(foo, bar, lst, string, mask), 1919cfe06f8SSteven Rostedt 1929cfe06f8SSteven Rostedt TP_STRUCT__entry( 1939cfe06f8SSteven Rostedt __array( char, foo, 10 ) 1949cfe06f8SSteven Rostedt __field( int, bar ) 1954e20e3a6SSteven Rostedt (Red Hat) __dynamic_array(int, list, __length_of(lst)) 1964e20e3a6SSteven Rostedt (Red Hat) __string( str, string ) 1974e20e3a6SSteven Rostedt (Red Hat) __bitmask( cpus, num_possible_cpus() ) 1989cfe06f8SSteven Rostedt ), 1999cfe06f8SSteven Rostedt 2009cfe06f8SSteven Rostedt TP_fast_assign( 201d8fae2f6SZhao Hongjiang strlcpy(__entry->foo, foo, 10); 2029cfe06f8SSteven Rostedt __entry->bar = bar; 2034e20e3a6SSteven Rostedt (Red Hat) memcpy(__get_dynamic_array(list), lst, 2044e20e3a6SSteven Rostedt (Red Hat) __length_of(lst) * sizeof(int)); 2054e20e3a6SSteven Rostedt (Red Hat) __assign_str(str, string); 2064e20e3a6SSteven Rostedt (Red Hat) __assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus()); 2079cfe06f8SSteven Rostedt ), 2089cfe06f8SSteven Rostedt 2094e20e3a6SSteven Rostedt (Red Hat) TP_printk("foo %s %d %s %s (%s)", __entry->foo, __entry->bar, 2104e20e3a6SSteven Rostedt (Red Hat) __print_array(__get_dynamic_array(list), 2114e20e3a6SSteven Rostedt (Red Hat) __get_dynamic_array_len(list), 2124e20e3a6SSteven Rostedt (Red Hat) sizeof(int)), 2134e20e3a6SSteven Rostedt (Red Hat) __get_str(str), __get_bitmask(cpus)) 2149cfe06f8SSteven Rostedt ); 2159cfe06f8SSteven Rostedt #endif 2169cfe06f8SSteven Rostedt 2179cfe06f8SSteven Rostedt /***** NOTICE! The #if protection ends here. *****/ 2189cfe06f8SSteven Rostedt 2199cfe06f8SSteven Rostedt 2209cfe06f8SSteven Rostedt /* 2219cfe06f8SSteven Rostedt * There are several ways I could have done this. If I left out the 2229cfe06f8SSteven Rostedt * TRACE_INCLUDE_PATH, then it would default to the kernel source 2239cfe06f8SSteven Rostedt * include/trace/events directory. 2249cfe06f8SSteven Rostedt * 2259cfe06f8SSteven Rostedt * I could specify a path from the define_trace.h file back to this 2269cfe06f8SSteven Rostedt * file. 2279cfe06f8SSteven Rostedt * 2289cfe06f8SSteven Rostedt * #define TRACE_INCLUDE_PATH ../../samples/trace_events 2299cfe06f8SSteven Rostedt * 23044ad18e0SSteven Rostedt * But the safest and easiest way to simply make it use the directory 23144ad18e0SSteven Rostedt * that the file is in is to add in the Makefile: 2329cfe06f8SSteven Rostedt * 23344ad18e0SSteven Rostedt * CFLAGS_trace-events-sample.o := -I$(src) 2349cfe06f8SSteven Rostedt * 2359cfe06f8SSteven Rostedt * This will make sure the current path is part of the include 23644ad18e0SSteven Rostedt * structure for our file so that define_trace.h can find it. 2379cfe06f8SSteven Rostedt * 2389cfe06f8SSteven Rostedt * I could have made only the top level directory the include: 2399cfe06f8SSteven Rostedt * 2409cfe06f8SSteven Rostedt * CFLAGS_trace-events-sample.o := -I$(PWD) 2419cfe06f8SSteven Rostedt * 2429cfe06f8SSteven Rostedt * And then let the path to this directory be the TRACE_INCLUDE_PATH: 2439cfe06f8SSteven Rostedt * 2449cfe06f8SSteven Rostedt * #define TRACE_INCLUDE_PATH samples/trace_events 2459cfe06f8SSteven Rostedt * 24644ad18e0SSteven Rostedt * But then if something defines "samples" or "trace_events" as a macro 24744ad18e0SSteven Rostedt * then we could risk that being converted too, and give us an unexpected 2489cfe06f8SSteven Rostedt * result. 2499cfe06f8SSteven Rostedt */ 2509cfe06f8SSteven Rostedt #undef TRACE_INCLUDE_PATH 25171e1c8acSSteven Rostedt #undef TRACE_INCLUDE_FILE 2529cfe06f8SSteven Rostedt #define TRACE_INCLUDE_PATH . 25371e1c8acSSteven Rostedt /* 25471e1c8acSSteven Rostedt * TRACE_INCLUDE_FILE is not needed if the filename and TRACE_SYSTEM are equal 25571e1c8acSSteven Rostedt */ 25671e1c8acSSteven Rostedt #define TRACE_INCLUDE_FILE trace-events-sample 2579cfe06f8SSteven Rostedt #include <trace/define_trace.h> 258