Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

5 files changed, 934 insertions, 0 deletions

diff --git a/samples/trace_events/Makefile b/samples/trace_events/Makefile
new file mode 100644
index 000000000..b3808bb4c
--- /dev/null
+++ b/samples/trace_events/Makefile
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# builds the trace events example kernel modules;
+# then to use one (as root):  insmod <module_name.ko>
+
+# If you include a trace header outside of include/trace/events
+# then the file that does the #define CREATE_TRACE_POINTS must
+# have that tracer file in its main search path. This is because
+# define_trace.h will include it, and must be able to find it from
+# the include/trace directory.
+#
+# Here trace-events-sample.c does the CREATE_TRACE_POINTS.
+#
+CFLAGS_trace-events-sample.o := -I$(src)
+CFLAGS_trace_custom_sched.o := -I$(src)
+
+obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace-events-sample.o
+obj-$(CONFIG_SAMPLE_TRACE_CUSTOM_EVENTS) += trace_custom_sched.o
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
new file mode 100644
index 000000000..608c4ae3b
--- /dev/null
+++ b/samples/trace_events/trace-events-sample.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+#include <linux/kthread.h>
+
+/*
+ * Any file that uses trace points, must include the header.
+ * But only one file, must include the header by defining
+ * CREATE_TRACE_POINTS first.  This will make the C code that
+ * creates the handles for the trace points.
+ */
+#define CREATE_TRACE_POINTS
+#include "trace-events-sample.h"
+
+static const char *random_strings[] = {
+	"Mother Goose",
+	"Snoopy",
+	"Gandalf",
+	"Frodo",
+	"One ring to rule them all"
+};
+
+static void do_simple_thread_func(int cnt, const char *fmt, ...)
+{
+	unsigned long bitmask[1] = {0xdeadbeefUL};
+	va_list va;
+	int array[6];
+	int len = cnt % 5;
+	int i;
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	schedule_timeout(HZ);
+
+	for (i = 0; i < len; i++)
+		array[i] = i + 1;
+	array[i] = 0;
+
+	va_start(va, fmt);
+
+	/* Silly tracepoints */
+	trace_foo_bar("hello", cnt, array, random_strings[len],
+		      current->cpus_ptr, fmt, &va);
+
+	va_end(va);
+
+	trace_foo_with_template_simple("HELLO", cnt);
+
+	trace_foo_bar_with_cond("Some times print", cnt);
+
+	trace_foo_with_template_cond("prints other times", cnt);
+
+	trace_foo_with_template_print("I have to be different", cnt);
+
+	trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask);
+}
+
+static void simple_thread_func(int cnt)
+{
+	do_simple_thread_func(cnt, "iter=%d", cnt);
+}
+
+static int simple_thread(void *arg)
+{
+	int cnt = 0;
+
+	while (!kthread_should_stop())
+		simple_thread_func(cnt++);
+
+	return 0;
+}
+
+static struct task_struct *simple_tsk;
+static struct task_struct *simple_tsk_fn;
+
+static void simple_thread_func_fn(int cnt)
+{
+	set_current_state(TASK_INTERRUPTIBLE);
+	schedule_timeout(HZ);
+
+	/* More silly tracepoints */
+	trace_foo_bar_with_fn("Look at me", cnt);
+	trace_foo_with_template_fn("Look at me too", cnt);
+}
+
+static int simple_thread_fn(void *arg)
+{
+	int cnt = 0;
+
+	while (!kthread_should_stop())
+		simple_thread_func_fn(cnt++);
+
+	return 0;
+}
+
+static DEFINE_MUTEX(thread_mutex);
+static int simple_thread_cnt;
+
+int foo_bar_reg(void)
+{
+	mutex_lock(&thread_mutex);
+	if (simple_thread_cnt++)
+		goto out;
+
+	pr_info("Starting thread for foo_bar_fn\n");
+	/*
+	 * We shouldn't be able to start a trace when the module is
+	 * unloading (there's other locks to prevent that). But
+	 * for consistency sake, we still take the thread_mutex.
+	 */
+	simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
+ out:
+	mutex_unlock(&thread_mutex);
+	return 0;
+}
+
+void foo_bar_unreg(void)
+{
+	mutex_lock(&thread_mutex);
+	if (--simple_thread_cnt)
+		goto out;
+
+	pr_info("Killing thread for foo_bar_fn\n");
+	if (simple_tsk_fn)
+		kthread_stop(simple_tsk_fn);
+	simple_tsk_fn = NULL;
+ out:
+	mutex_unlock(&thread_mutex);
+}
+
+static int __init trace_event_init(void)
+{
+	simple_tsk = kthread_run(simple_thread, NULL, "event-sample");
+	if (IS_ERR(simple_tsk))
+		return -1;
+
+	return 0;
+}
+
+static void __exit trace_event_exit(void)
+{
+	kthread_stop(simple_tsk);
+	mutex_lock(&thread_mutex);
+	if (simple_tsk_fn)
+		kthread_stop(simple_tsk_fn);
+	simple_tsk_fn = NULL;
+	mutex_unlock(&thread_mutex);
+}
+
+module_init(trace_event_init);
+module_exit(trace_event_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("trace-events-sample");
+MODULE_LICENSE("GPL");
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
new file mode 100644
index 000000000..1a9222620
--- /dev/null
+++ b/samples/trace_events/trace-events-sample.h
@@ -0,0 +1,608 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * If TRACE_SYSTEM is defined, that will be the directory created
+ * in the ftrace directory under /sys/kernel/tracing/events/<system>
+ *
+ * The define_trace.h below will also look for a file name of
+ * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
+ * In this case, it would look for sample-trace.h
+ *
+ * If the header name will be different than the system name
+ * (as in this case), then you can override the header name that
+ * define_trace.h will look up by defining TRACE_INCLUDE_FILE
+ *
+ * This file is called trace-events-sample.h but we want the system
+ * to be called "sample-trace". Therefore we must define the name of this
+ * file:
+ *
+ * #define TRACE_INCLUDE_FILE trace-events-sample
+ *
+ * As we do an the bottom of this file.
+ *
+ * Notice that TRACE_SYSTEM should be defined outside of #if
+ * protection, just like TRACE_INCLUDE_FILE.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM sample-trace
+
+/*
+ * TRACE_SYSTEM is expected to be a C valid variable (alpha-numeric
+ * and underscore), although it may start with numbers. If for some
+ * reason it is not, you need to add the following lines:
+ */
+#undef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR sample_trace
+/*
+ * But the above is only needed if TRACE_SYSTEM is not alpha-numeric
+ * and underscored. By default, TRACE_SYSTEM_VAR will be equal to
+ * TRACE_SYSTEM. As TRACE_SYSTEM_VAR must be alpha-numeric, if
+ * TRACE_SYSTEM is not, then TRACE_SYSTEM_VAR must be defined with
+ * only alpha-numeric and underscores.
+ *
+ * The TRACE_SYSTEM_VAR is only used internally and not visible to
+ * user space.
+ */
+
+/*
+ * Notice that this file is not protected like a normal header.
+ * We also must allow for rereading of this file. The
+ *
+ *  || defined(TRACE_HEADER_MULTI_READ)
+ *
+ * serves this purpose.
+ */
+#if !defined(_TRACE_EVENT_SAMPLE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_EVENT_SAMPLE_H
+
+/*
+ * All trace headers should include tracepoint.h, until we finally
+ * make it into a standard header.
+ */
+#include <linux/tracepoint.h>
+
+/*
+ * The TRACE_EVENT macro is broken up into 5 parts.
+ *
+ * name: name of the trace point. This is also how to enable the tracepoint.
+ *   A function called trace_foo_bar() will be created.
+ *
+ * proto: the prototype of the function trace_foo_bar()
+ *   Here it is trace_foo_bar(char *foo, int bar).
+ *
+ * args:  must match the arguments in the prototype.
+ *    Here it is simply "foo, bar".
+ *
+ * struct:  This defines the way the data will be stored in the ring buffer.
+ *          The items declared here become part of a special structure
+ *          called "__entry", which can be used in the fast_assign part of the
+ *          TRACE_EVENT macro.
+ *
+ *      Here are the currently defined types you can use:
+ *
+ *   __field : Is broken up into type and name. Where type can be any
+ *         primitive type (integer, long or pointer).
+ *
+ *        __field(int, foo)
+ *
+ *        __entry->foo = 5;
+ *
+ *   __field_struct : This can be any static complex data type (struct, union
+ *         but not an array). Be careful using complex types, as each
+ *         event is limited in size, and copying large amounts of data
+ *         into the ring buffer can slow things down.
+ *
+ *         __field_struct(struct bar, foo)
+ *
+ *         __entry->bar.x = y;
+
+ *   __array: There are three fields (type, name, size). The type is the
+ *         type of elements in the array, the name is the name of the array.
+ *         size is the number of items in the array (not the total size).
+ *
+ *         __array( char, foo, 10) is the same as saying: char foo[10];
+ *
+ *         Assigning arrays can be done like any array:
+ *
+ *         __entry->foo[0] = 'a';
+ *
+ *         memcpy(__entry->foo, bar, 10);
+ *
+ *   __dynamic_array: This is similar to array, but can vary its size from
+ *         instance to instance of the tracepoint being called.
+ *         Like __array, this too has three elements (type, name, size);
+ *         type is the type of the element, name is the name of the array.
+ *         The size is different than __array. It is not a static number,
+ *         but the algorithm to figure out the length of the array for the
+ *         specific instance of tracepoint. Again, size is the number of
+ *         items in the array, not the total length in bytes.
+ *
+ *         __dynamic_array( int, foo, bar) is similar to: int foo[bar];
+ *
+ *         Note, unlike arrays, you must use the __get_dynamic_array() macro
+ *         to access the array.
+ *
+ *         memcpy(__get_dynamic_array(foo), bar, 10);
+ *
+ *         Notice, that "__entry" is not needed here.
+ *
+ *   __string: This is a special kind of __dynamic_array. It expects to
+ *         have a null terminated character array passed to it (it allows
+ *         for NULL too, which would be converted into "(null)"). __string
+ *         takes two parameter (name, src), where name is the name of
+ *         the string saved, and src is the string to copy into the
+ *         ring buffer.
+ *
+ *         __string(foo, bar)  is similar to:  strcpy(foo, bar)
+ *
+ *         To assign a string, use the helper macro __assign_str().
+ *
+ *         __assign_str(foo, bar);
+ *
+ *         In most cases, the __assign_str() macro will take the same
+ *         parameters as the __string() macro had to declare the string.
+ *
+ *   __vstring: This is similar to __string() but instead of taking a
+ *         dynamic length, it takes a variable list va_list 'va' variable.
+ *         Some event callers already have a message from parameters saved
+ *         in a va_list. Passing in the format and the va_list variable
+ *         will save just enough on the ring buffer for that string.
+ *         Note, the va variable used is a pointer to a va_list, not
+ *         to the va_list directly.
+ *
+ *           (va_list *va)
+ *
+ *         __vstring(foo, fmt, va)  is similar to:  vsnprintf(foo, fmt, va)
+ *
+ *         To assign the string, use the helper macro __assign_vstr().
+ *
+ *         __assign_vstr(foo, fmt, va);
+ *
+ *         In most cases, the __assign_vstr() macro will take the same
+ *         parameters as the __vstring() macro had to declare the string.
+ *         Use __get_str() to retrieve the __vstring() just like it would for
+ *         __string().
+ *
+ *   __string_len: This is a helper to a __dynamic_array, but it understands
+ *	   that the array has characters in it, and with the combined
+ *         use of __assign_str_len(), it will allocate 'len' + 1 bytes
+ *         in the ring buffer and add a '\0' to the string. This is
+ *         useful if the string being saved has no terminating '\0' byte.
+ *         It requires that the length of the string is known as it acts
+ *         like a memcpy().
+ *
+ *         Declared with:
+ *
+ *         __string_len(foo, bar, len)
+ *
+ *         To assign this string, use the helper macro __assign_str_len().
+ *
+ *         __assign_str_len(foo, bar, len);
+ *
+ *         Then len + 1 is allocated to the ring buffer, and a nul terminating
+ *         byte is added. This is similar to:
+ *
+ *         memcpy(__get_str(foo), bar, len);
+ *         __get_str(foo)[len] = 0;
+ *
+ *        The advantage of using this over __dynamic_array, is that it
+ *        takes care of allocating the extra byte on the ring buffer
+ *        for the '\0' terminating byte, and __get_str(foo) can be used
+ *        in the TP_printk().
+ *
+ *   __bitmask: This is another kind of __dynamic_array, but it expects
+ *         an array of longs, and the number of bits to parse. It takes
+ *         two parameters (name, nr_bits), where name is the name of the
+ *         bitmask to save, and the nr_bits is the number of bits to record.
+ *
+ *         __bitmask(target_cpu, nr_cpumask_bits)
+ *
+ *         To assign a bitmask, use the __assign_bitmask() helper macro.
+ *
+ *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
+ *
+ *
+ * fast_assign: This is a C like function that is used to store the items
+ *    into the ring buffer. A special variable called "__entry" will be the
+ *    structure that points into the ring buffer and has the same fields as
+ *    described by the struct part of TRACE_EVENT above.
+ *
+ * printk: This is a way to print out the data in pretty print. This is
+ *    useful if the system crashes and you are logging via a serial line,
+ *    the data can be printed to the console using this "printk" method.
+ *    This is also used to print out the data from the trace files.
+ *    Again, the __entry macro is used to access the data from the ring buffer.
+ *
+ *    Note, __dynamic_array, __string, and __bitmask require special helpers
+ *       to access the data.
+ *
+ *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
+ *            Use __get_dynamic_array_len(foo) to get the length of the array
+ *            saved. Note, __get_dynamic_array_len() returns the total allocated
+ *            length of the dynamic array; __print_array() expects the second
+ *            parameter to be the number of elements. To get that, the array length
+ *            needs to be divided by the element size.
+ *
+ *      For __string(foo, bar) use __get_str(foo)
+ *
+ *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
+ *
+ *
+ * Note, that for both the assign and the printk, __entry is the handler
+ * to the data structure in the ring buffer, and is defined by the
+ * TP_STRUCT__entry.
+ */
+
+/*
+ * It is OK to have helper functions in the file, but they need to be protected
+ * from being defined more than once. Remember, this file gets included more
+ * than once.
+ */
+#ifndef __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS
+#define __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS
+static inline int __length_of(const int *list)
+{
+	int i;
+
+	if (!list)
+		return 0;
+
+	for (i = 0; list[i]; i++)
+		;
+	return i;
+}
+
+enum {
+	TRACE_SAMPLE_FOO = 2,
+	TRACE_SAMPLE_BAR = 4,
+	TRACE_SAMPLE_ZOO = 8,
+};
+#endif
+
+/*
+ * If enums are used in the TP_printk(), their names will be shown in
+ * format files and not their values. This can cause problems with user
+ * space programs that parse the format files to know how to translate
+ * the raw binary trace output into human readable text.
+ *
+ * To help out user space programs, any enum that is used in the TP_printk()
+ * should be defined by TRACE_DEFINE_ENUM() macro. All that is needed to
+ * be done is to add this macro with the enum within it in the trace
+ * header file, and it will be converted in the output.
+ */
+
+TRACE_DEFINE_ENUM(TRACE_SAMPLE_FOO);
+TRACE_DEFINE_ENUM(TRACE_SAMPLE_BAR);
+TRACE_DEFINE_ENUM(TRACE_SAMPLE_ZOO);
+
+TRACE_EVENT(foo_bar,
+
+	TP_PROTO(const char *foo, int bar, const int *lst,
+		 const char *string, const struct cpumask *mask,
+		 const char *fmt, va_list *va),
+
+	TP_ARGS(foo, bar, lst, string, mask, fmt, va),
+
+	TP_STRUCT__entry(
+		__array(	char,	foo,    10		)
+		__field(	int,	bar			)
+		__dynamic_array(int,	list,   __length_of(lst))
+		__string(	str,	string			)
+		__bitmask(	cpus,	num_possible_cpus()	)
+		__vstring(	vstr,	fmt,	va		)
+	),
+
+	TP_fast_assign(
+		strlcpy(__entry->foo, foo, 10);
+		__entry->bar	= bar;
+		memcpy(__get_dynamic_array(list), lst,
+		       __length_of(lst) * sizeof(int));
+		__assign_str(str, string);
+		__assign_vstr(vstr, fmt, va);
+		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+	),
+
+	TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar,
+
+/*
+ * Notice here the use of some helper functions. This includes:
+ *
+ *  __print_symbolic( variable, { value, "string" }, ... ),
+ *
+ *    The variable is tested against each value of the { } pair. If
+ *    the variable matches one of the values, then it will print the
+ *    string in that pair. If non are matched, it returns a string
+ *    version of the number (if __entry->bar == 7 then "7" is returned).
+ */
+		  __print_symbolic(__entry->bar,
+				   { 0, "zero" },
+				   { TRACE_SAMPLE_FOO, "TWO" },
+				   { TRACE_SAMPLE_BAR, "FOUR" },
+				   { TRACE_SAMPLE_ZOO, "EIGHT" },
+				   { 10, "TEN" }
+			  ),
+
+/*
+ *  __print_flags( variable, "delim", { value, "flag" }, ... ),
+ *
+ *    This is similar to __print_symbolic, except that it tests the bits
+ *    of the value. If ((FLAG & variable) == FLAG) then the string is
+ *    printed. If more than one flag matches, then each one that does is
+ *    also printed with delim in between them.
+ *    If not all bits are accounted for, then the not found bits will be
+ *    added in hex format: 0x506 will show BIT2|BIT4|0x500
+ */
+		  __print_flags(__entry->bar, "|",
+				{ 1, "BIT1" },
+				{ 2, "BIT2" },
+				{ 4, "BIT3" },
+				{ 8, "BIT4" }
+			  ),
+/*
+ *  __print_array( array, len, element_size )
+ *
+ *    This prints out the array that is defined by __array in a nice format.
+ */
+		  __print_array(__get_dynamic_array(list),
+				__get_dynamic_array_len(list) / sizeof(int),
+				sizeof(int)),
+		  __get_str(str), __get_bitmask(cpus), __get_str(vstr))
+);
+
+/*
+ * There may be a case where a tracepoint should only be called if
+ * some condition is set. Otherwise the tracepoint should not be called.
+ * But to do something like:
+ *
+ *  if (cond)
+ *     trace_foo();
+ *
+ * Would cause a little overhead when tracing is not enabled, and that
+ * overhead, even if small, is not something we want. As tracepoints
+ * use static branch (aka jump_labels), where no branch is taken to
+ * skip the tracepoint when not enabled, and a jmp is placed to jump
+ * to the tracepoint code when it is enabled, having a if statement
+ * nullifies that optimization. It would be nice to place that
+ * condition within the static branch. This is where TRACE_EVENT_CONDITION
+ * comes in.
+ *
+ * TRACE_EVENT_CONDITION() is just like TRACE_EVENT, except it adds another
+ * parameter just after args. Where TRACE_EVENT has:
+ *
+ * TRACE_EVENT(name, proto, args, struct, assign, printk)
+ *
+ * the CONDITION version has:
+ *
+ * TRACE_EVENT_CONDITION(name, proto, args, cond, struct, assign, printk)
+ *
+ * Everything is the same as TRACE_EVENT except for the new cond. Think
+ * of the cond variable as:
+ *
+ *   if (cond)
+ *      trace_foo_bar_with_cond();
+ *
+ * Except that the logic for the if branch is placed after the static branch.
+ * That is, the if statement that processes the condition will not be
+ * executed unless that traecpoint is enabled. Otherwise it still remains
+ * a nop.
+ */
+TRACE_EVENT_CONDITION(foo_bar_with_cond,
+
+	TP_PROTO(const char *foo, int bar),
+
+	TP_ARGS(foo, bar),
+
+	TP_CONDITION(!(bar % 10)),
+
+	TP_STRUCT__entry(
+		__string(	foo,    foo		)
+		__field(	int,	bar			)
+	),
+
+	TP_fast_assign(
+		__assign_str(foo, foo);
+		__entry->bar	= bar;
+	),
+
+	TP_printk("foo %s %d", __get_str(foo), __entry->bar)
+);
+
+int foo_bar_reg(void);
+void foo_bar_unreg(void);
+
+/*
+ * Now in the case that some function needs to be called when the
+ * tracepoint is enabled and/or when it is disabled, the
+ * TRACE_EVENT_FN() serves this purpose. This is just like TRACE_EVENT()
+ * but adds two more parameters at the end:
+ *
+ * TRACE_EVENT_FN( name, proto, args, struct, assign, printk, reg, unreg)
+ *
+ * reg and unreg are functions with the prototype of:
+ *
+ *    void reg(void)
+ *
+ * The reg function gets called before the tracepoint is enabled, and
+ * the unreg function gets called after the tracepoint is disabled.
+ *
+ * Note, reg and unreg are allowed to be NULL. If you only need to
+ * call a function before enabling, or after disabling, just set one
+ * function and pass in NULL for the other parameter.
+ */
+TRACE_EVENT_FN(foo_bar_with_fn,
+
+	TP_PROTO(const char *foo, int bar),
+
+	TP_ARGS(foo, bar),
+
+	TP_STRUCT__entry(
+		__string(	foo,    foo		)
+		__field(	int,	bar		)
+	),
+
+	TP_fast_assign(
+		__assign_str(foo, foo);
+		__entry->bar	= bar;
+	),
+
+	TP_printk("foo %s %d", __get_str(foo), __entry->bar),
+
+	foo_bar_reg, foo_bar_unreg
+);
+
+/*
+ * Each TRACE_EVENT macro creates several helper functions to produce
+ * the code to add the tracepoint, create the files in the trace
+ * directory, hook it to perf, assign the values and to print out
+ * the raw data from the ring buffer. To prevent too much bloat,
+ * if there are more than one tracepoint that uses the same format
+ * for the proto, args, struct, assign and printk, and only the name
+ * is different, it is highly recommended to use the DECLARE_EVENT_CLASS
+ *
+ * DECLARE_EVENT_CLASS() macro creates most of the functions for the
+ * tracepoint. Then DEFINE_EVENT() is use to hook a tracepoint to those
+ * functions. This DEFINE_EVENT() is an instance of the class and can
+ * be enabled and disabled separately from other events (either TRACE_EVENT
+ * or other DEFINE_EVENT()s).
+ *
+ * Note, TRACE_EVENT() itself is simply defined as:
+ *
+ * #define TRACE_EVENT(name, proto, args, tstruct, assign, printk)  \
+ *  DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, printk); \
+ *  DEFINE_EVENT(name, name, proto, args)
+ *
+ * The DEFINE_EVENT() also can be declared with conditions and reg functions:
+ *
+ * DEFINE_EVENT_CONDITION(template, name, proto, args, cond);
+ * DEFINE_EVENT_FN(template, name, proto, args, reg, unreg);
+ */
+DECLARE_EVENT_CLASS(foo_template,
+
+	TP_PROTO(const char *foo, int bar),
+
+	TP_ARGS(foo, bar),
+
+	TP_STRUCT__entry(
+		__string(	foo,    foo		)
+		__field(	int,	bar		)
+	),
+
+	TP_fast_assign(
+		__assign_str(foo, foo);
+		__entry->bar	= bar;
+	),
+
+	TP_printk("foo %s %d", __get_str(foo), __entry->bar)
+);
+
+/*
+ * Here's a better way for the previous samples (except, the first
+ * example had more fields and could not be used here).
+ */
+DEFINE_EVENT(foo_template, foo_with_template_simple,
+	TP_PROTO(const char *foo, int bar),
+	TP_ARGS(foo, bar));
+
+DEFINE_EVENT_CONDITION(foo_template, foo_with_template_cond,
+	TP_PROTO(const char *foo, int bar),
+	TP_ARGS(foo, bar),
+	TP_CONDITION(!(bar % 8)));
+
+
+DEFINE_EVENT_FN(foo_template, foo_with_template_fn,
+	TP_PROTO(const char *foo, int bar),
+	TP_ARGS(foo, bar),
+	foo_bar_reg, foo_bar_unreg);
+
+/*
+ * Anytime two events share basically the same values and have
+ * the same output, use the DECLARE_EVENT_CLASS() and DEFINE_EVENT()
+ * when ever possible.
+ */
+
+/*
+ * If the event is similar to the DECLARE_EVENT_CLASS, but you need
+ * to have a different output, then use DEFINE_EVENT_PRINT() which
+ * lets you override the TP_printk() of the class.
+ */
+
+DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,
+	TP_PROTO(const char *foo, int bar),
+	TP_ARGS(foo, bar),
+	TP_printk("bar %s %d", __get_str(foo), __entry->bar));
+
+/*
+ * There are yet another __rel_loc dynamic data attribute. If you
+ * use __rel_dynamic_array() and __rel_string() etc. macros, you
+ * can use this attribute. There is no difference from the viewpoint
+ * of functionality with/without 'rel' but the encoding is a bit
+ * different. This is expected to be used with user-space event,
+ * there is no reason that the kernel event use this, but only for
+ * testing.
+ */
+
+TRACE_EVENT(foo_rel_loc,
+
+	TP_PROTO(const char *foo, int bar, unsigned long *mask),
+
+	TP_ARGS(foo, bar, mask),
+
+	TP_STRUCT__entry(
+		__rel_string(	foo,	foo	)
+		__field(	int,	bar	)
+		__rel_bitmask(	bitmask,
+			BITS_PER_BYTE * sizeof(unsigned long)	)
+	),
+
+	TP_fast_assign(
+		__assign_rel_str(foo, foo);
+		__entry->bar = bar;
+		__assign_rel_bitmask(bitmask, mask,
+			BITS_PER_BYTE * sizeof(unsigned long));
+	),
+
+	TP_printk("foo_rel_loc %s, %d, %s", __get_rel_str(foo), __entry->bar,
+		  __get_rel_bitmask(bitmask))
+);
+#endif
+
+/***** NOTICE! The #if protection ends here. *****/
+
+
+/*
+ * There are several ways I could have done this. If I left out the
+ * TRACE_INCLUDE_PATH, then it would default to the kernel source
+ * include/trace/events directory.
+ *
+ * I could specify a path from the define_trace.h file back to this
+ * file.
+ *
+ * #define TRACE_INCLUDE_PATH ../../samples/trace_events
+ *
+ * But the safest and easiest way to simply make it use the directory
+ * that the file is in is to add in the Makefile:
+ *
+ * CFLAGS_trace-events-sample.o := -I$(src)
+ *
+ * This will make sure the current path is part of the include
+ * structure for our file so that define_trace.h can find it.
+ *
+ * I could have made only the top level directory the include:
+ *
+ * CFLAGS_trace-events-sample.o := -I$(PWD)
+ *
+ * And then let the path to this directory be the TRACE_INCLUDE_PATH:
+ *
+ * #define TRACE_INCLUDE_PATH samples/trace_events
+ *
+ * But then if something defines "samples" or "trace_events" as a macro
+ * then we could risk that being converted too, and give us an unexpected
+ * result.
+ */
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_PATH .
+/*
+ * TRACE_INCLUDE_FILE is not needed if the filename and TRACE_SYSTEM are equal
+ */
+#define TRACE_INCLUDE_FILE trace-events-sample
+#include <trace/define_trace.h>
diff --git a/samples/trace_events/trace_custom_sched.c b/samples/trace_events/trace_custom_sched.c
new file mode 100644
index 000000000..b99d9ab7d
--- /dev/null
+++ b/samples/trace_events/trace_custom_sched.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * event tracer
+ *
+ * Copyright (C) 2022 Google Inc, Steven Rostedt <rostedt@goodmis.org>
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/trace_events.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+
+/*
+ * Must include the event header that the custom event will attach to,
+ * from the C file, and not in the custom header file.
+ */
+#include <trace/events/sched.h>
+
+/* Declare CREATE_CUSTOM_TRACE_EVENTS before including custom header */
+#define CREATE_CUSTOM_TRACE_EVENTS
+
+#include "trace_custom_sched.h"
+
+/*
+ * As the trace events are not exported to modules, the use of
+ * for_each_kernel_tracepoint() is needed to find the trace event
+ * to attach to. The fct() function below, is a callback that
+ * will be called for every event.
+ *
+ * Helper functions are created by the TRACE_CUSTOM_EVENT() macro
+ * update the event. Those are of the form:
+ *
+ *    trace_custom_event_<event>_update()
+ *
+ * Where <event> is the event to attach.
+ */
+static void fct(struct tracepoint *tp, void *priv)
+{
+	trace_custom_event_sched_switch_update(tp);
+	trace_custom_event_sched_waking_update(tp);
+}
+
+static int __init trace_sched_init(void)
+{
+	for_each_kernel_tracepoint(fct, NULL);
+	return 0;
+}
+
+static void __exit trace_sched_exit(void)
+{
+}
+
+module_init(trace_sched_init);
+module_exit(trace_sched_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("Custom scheduling events");
+MODULE_LICENSE("GPL");
diff --git a/samples/trace_events/trace_custom_sched.h b/samples/trace_events/trace_custom_sched.h
new file mode 100644
index 000000000..951388334
--- /dev/null
+++ b/samples/trace_events/trace_custom_sched.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Like the headers that use TRACE_EVENT(), the TRACE_CUSTOM_EVENT()
+ * needs a header that allows for multiple inclusions.
+ *
+ * Test for a unique name (here we have _TRACE_CUSTOM_SCHED_H),
+ * also allowing to continue if TRACE_CUSTOM_MULTI_READ is defined.
+ */
+#if !defined(_TRACE_CUSTOM_SCHED_H) || defined(TRACE_CUSTOM_MULTI_READ)
+#define _TRACE_CUSTOM_SCHED_H
+
+/* Include linux/trace_events.h for initial defines of TRACE_CUSTOM_EVENT() */
+#include <linux/trace_events.h>
+
+/*
+ * TRACE_CUSTOM_EVENT() is just like TRACE_EVENT(). The first parameter
+ * is the event name of an existing event where the TRACE_EVENT has been included
+ * in the C file before including this file.
+ */
+TRACE_CUSTOM_EVENT(sched_switch,
+
+	/*
+	 * The TP_PROTO() and TP_ARGS must match the trace event
+	 * that the custom event is using.
+	 */
+	TP_PROTO(bool preempt,
+		 struct task_struct *prev,
+		 struct task_struct *next,
+		 unsigned int prev_state),
+
+	TP_ARGS(preempt, prev, next, prev_state),
+
+	/*
+	 * The next fields are where the customization happens.
+	 * The TP_STRUCT__entry() defines what will be recorded
+	 * in the ring buffer when the custom event triggers.
+	 *
+	 * The rest is just like the TRACE_EVENT() macro except that
+	 * it uses the custom entry.
+	 */
+	TP_STRUCT__entry(
+		__field(	unsigned short,		prev_prio	)
+		__field(	unsigned short,		next_prio	)
+		__field(	pid_t,	next_pid			)
+	),
+
+	TP_fast_assign(
+		__entry->prev_prio	= prev->prio;
+		__entry->next_pid	= next->pid;
+		__entry->next_prio	= next->prio;
+	),
+
+	TP_printk("prev_prio=%d next_pid=%d next_prio=%d",
+		  __entry->prev_prio, __entry->next_pid, __entry->next_prio)
+)
+
+
+TRACE_CUSTOM_EVENT(sched_waking,
+
+	TP_PROTO(struct task_struct *p),
+
+	TP_ARGS(p),
+
+	TP_STRUCT__entry(
+		__field(	pid_t,			pid	)
+		__field(	unsigned short,		prio	)
+	),
+
+	TP_fast_assign(
+		__entry->pid	= p->pid;
+		__entry->prio	= p->prio;
+	),
+
+	TP_printk("pid=%d prio=%d", __entry->pid, __entry->prio)
+)
+#endif
+/*
+ * Just like the headers that create TRACE_EVENTs, the below must
+ * be outside the protection of the above #if block.
+ */
+
+/*
+ * It is required that the Makefile includes:
+ *    CFLAGS_<c_file>.o := -I$(src)
+ */
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_PATH .
+
+/*
+ * It is requred that the TRACE_INCLUDE_FILE be the same
+ * as this file without the ".h".
+ */
+#define TRACE_INCLUDE_FILE trace_custom_sched
+#include <trace/define_custom_trace.h>