linux_kernel/include/trace/ftrace.h

/*
 * Stage 1 of the trace events.
 *
 * Override the macros in <trace/trace_events.h> to include the following:
 *
 * struct ftrace_raw_<call> {
 *	struct trace_entry		ent;
 *	<type>				<item>;
 *	<type2>				<item2>[<len>];
 *	[...]
 * };
 *
 * The <type> <item> is created by the __field(type, item) macro or
 * the __array(type2, item2, len) macro.
 * We simply do "type item;", and that will create the fields
 * in the structure.
 */

#include <linux/ftrace_event.h>

/*
 * DECLARE_EVENT_CLASS can be used to add a generic function
 * handlers for events. That is, if all events have the same
 * parameters and just have distinct trace points.
 * Each tracepoint can be defined with DEFINE_EVENT and that
 * will map the DECLARE_EVENT_CLASS to the tracepoint.
 *
 * TRACE_EVENT is a one to one mapping between tracepoint and template.
 */
#undef TRACE_EVENT
#define TRACE_EVENT(name, proto, args, tstruct, assign, print) \
	DECLARE_EVENT_CLASS(name,			       \
			     PARAMS(proto),		       \
			     PARAMS(args),		       \
			     PARAMS(tstruct),		       \
			     PARAMS(assign),		       \
			     PARAMS(print));		       \
	DEFINE_EVENT(name, name, PARAMS(proto), PARAMS(args));


#undef __field
#define __field(type, item)		type	item;

#undef __field_ext
#define __field_ext(type, item, filter_type)	type	item;

#undef __array
#define __array(type, item, len)	type	item[len];

#undef __dynamic_array
#define __dynamic_array(type, item, len) u32 __data_loc_##item;

#undef __string
#define __string(item, src) __dynamic_array(char, item, -1)

#undef TP_STRUCT__entry
#define TP_STRUCT__entry(args...) args

#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)	\
	struct ftrace_raw_##name {					\
		struct trace_entry	ent;				\
		tstruct							\
		char			__data[0];			\
	};								\
									\
	static struct ftrace_event_class event_class_##name;

#undef DEFINE_EVENT
#define DEFINE_EVENT(template, name, proto, args)	\
	static struct ftrace_event_call	__used		\
	__attribute__((__aligned__(4))) event_##name

#undef DEFINE_EVENT_FN
#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)	\
	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))

#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))

/* Callbacks are meaningless to ftrace. */
#undef TRACE_EVENT_FN
#define TRACE_EVENT_FN(name, proto, args, tstruct,			\
		assign, print, reg, unreg)				\
	TRACE_EVENT(name, PARAMS(proto), PARAMS(args),			\
		PARAMS(tstruct), PARAMS(assign), PARAMS(print))		\

#undef TRACE_EVENT_FLAGS
#define TRACE_EVENT_FLAGS(name, value)					\
	__TRACE_EVENT_FLAGS(name, value)

#undef TRACE_EVENT_PERF_PERM
#define TRACE_EVENT_PERF_PERM(name, expr...)				\
	__TRACE_EVENT_PERF_PERM(name, expr)

#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)


/*
 * Stage 2 of the trace events.
 *
 * Include the following:
 *
 * struct ftrace_data_offsets_<call> {
 *	u32				<item1>;
 *	u32				<item2>;
 *	[...]
 * };
 *
 * The __dynamic_array() macro will create each u32 <item>, this is
 * to keep the offset of each array from the beginning of the event.
 * The size of an array is also encoded, in the higher 16 bits of <item>.
 */

#undef __field
#define __field(type, item)

#undef __field_ext
#define __field_ext(type, item, filter_type)

#undef __array
#define __array(type, item, len)

#undef __dynamic_array
#define __dynamic_array(type, item, len)	u32 item;

#undef __string
#define __string(item, src) __dynamic_array(char, item, -1)

#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
	struct ftrace_data_offsets_##call {				\
		tstruct;						\
	};

#undef DEFINE_EVENT
#define DEFINE_EVENT(template, name, proto, args)

#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))

#undef TRACE_EVENT_FLAGS
#define TRACE_EVENT_FLAGS(event, flag)

#undef TRACE_EVENT_PERF_PERM
#define TRACE_EVENT_PERF_PERM(event, expr...)

#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)

/*
 * Stage 3 of the trace events.
 *
 * Override the macros in <trace/trace_events.h> to include the following:
 *
 * enum print_line_t
 * ftrace_raw_output_<call>(struct trace_iterator *iter, int flags)
 * {
 *	struct trace_seq *s = &iter->seq;
 *	struct ftrace_raw_<call> *field; <-- defined in stage 1
 *	struct trace_entry *entry;
 *	struct trace_seq *p = &iter->tmp_seq;
 *	int ret;
 *
 *	entry = iter->ent;
 *
 *	if (entry->type != event_<call>->event.type) {
 *		WARN_ON_ONCE(1);
 *		return TRACE_TYPE_UNHANDLED;
 *	}
 *
 *	field = (typeof(field))entry;
 *
 *	trace_seq_init(p);
 *	ret = trace_seq_printf(s, "%s: ", <call>);
 *	if (ret)
 *		ret = trace_seq_printf(s, <TP_printk> "\n");
 *	if (!ret)
 *		return TRACE_TYPE_PARTIAL_LINE;
 *
 *	return TRACE_TYPE_HANDLED;
 * }
 *
 * This is the method used to print the raw event to the trace
 * output format. Note, this is not needed if the data is read
 * in binary.
 */

#undef __entry
#define __entry field

#undef TP_printk
#define TP_printk(fmt, args...) fmt "\n", args

#undef __get_dynamic_array
#define __get_dynamic_array(field)	\
		((void *)__entry + (__entry->__data_loc_##field & 0xffff))

#undef __get_str
#define __get_str(field) (char *)__get_dynamic_array(field)

#undef __print_flags
#define __print_flags(flag, delim, flag_array...)			\
	({								\
		static const struct trace_print_flags __flags[] =	\
			{ flag_array, { -1, NULL }};			\
		ftrace_print_flags_seq(p, delim, flag, __flags);	\
	})

#undef __print_symbolic
#define __print_symbolic(value, symbol_array...)			\
	({								\
		static const struct trace_print_flags symbols[] =	\
			{ symbol_array, { -1, NULL }};			\
		ftrace_print_symbols_seq(p, value, symbols);		\
	})

#undef __print_symbolic_u64
#if BITS_PER_LONG == 32
#define __print_symbolic_u64(value, symbol_array...)			\
	({								\
		static const struct trace_print_flags_u64 symbols[] =	\
			{ symbol_array, { -1, NULL } };			\
		ftrace_print_symbols_seq_u64(p, value, symbols);	\
	})
#else
#define __print_symbolic_u64(value, symbol_array...)			\
			__print_symbolic(value, symbol_array)
#endif

#undef __print_hex
#define __print_hex(buf, buf_len) ftrace_print_hex_seq(p, buf, buf_len)

#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
static notrace enum print_line_t					\
ftrace_raw_output_##call(struct trace_iterator *iter, int flags,	\
			 struct trace_event *trace_event)		\
{									\
	struct trace_seq *s = &iter->seq;				\
	struct trace_seq __maybe_unused *p = &iter->tmp_seq;		\
	struct ftrace_raw_##call *field;				\
	int ret;							\
									\
	field = (typeof(field))iter->ent;				\
									\
	ret = ftrace_raw_output_prep(iter, trace_event);		\
	if (ret)							\
		return ret;						\
									\
	ret = trace_seq_printf(s, print);				\
	if (!ret)							\
		return TRACE_TYPE_PARTIAL_LINE;				\
									\
	return TRACE_TYPE_HANDLED;					\
}									\
static struct trace_event_functions ftrace_event_type_funcs_##call = {	\
	.trace			= ftrace_raw_output_##call,		\
};

#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, call, proto, args, print)		\
static notrace enum print_line_t					\
ftrace_raw_output_##call(struct trace_iterator *iter, int flags,	\
			 struct trace_event *event)			\
{									\
	struct ftrace_raw_##template *field;				\
	struct trace_entry *entry;					\
	struct trace_seq *p = &iter->tmp_seq;				\
									\
	entry = iter->ent;						\
									\
	if (entry->type != event_##call.event.type) {			\
		WARN_ON_ONCE(1);					\
		return TRACE_TYPE_UNHANDLED;				\
	}								\
									\
	field = (typeof(field))entry;					\
									\
	trace_seq_init(p);						\
	return ftrace_output_call(iter, #call, print);			\
}									\
static struct trace_event_functions ftrace_event_type_funcs_##call = {	\
	.trace			= ftrace_raw_output_##call,		\
};

#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)

#undef __field_ext
#define __field_ext(type, item, filter_type)				\
	ret = trace_define_field(event_call, #type, #item,		\
				 offsetof(typeof(field), item),		\
				 sizeof(field.item),			\
				 is_signed_type(type), filter_type);	\
	if (ret)							\
		return ret;

#undef __field
#define __field(type, item)	__field_ext(type, item, FILTER_OTHER)

#undef __array
#define __array(type, item, len)					\
	do {								\
		char *type_str = #type"["__stringify(len)"]";		\
		BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);			\
		ret = trace_define_field(event_call, type_str, #item,	\
				 offsetof(typeof(field), item),		\
				 sizeof(field.item),			\
				 is_signed_type(type), FILTER_OTHER);	\
		if (ret)						\
			return ret;					\
	} while (0);

#undef __dynamic_array
#define __dynamic_array(type, item, len)				       \
	ret = trace_define_field(event_call, "__data_loc " #type "[]", #item,  \
				 offsetof(typeof(field), __data_loc_##item),   \
				 sizeof(field.__data_loc_##item),	       \
				 is_signed_type(type), FILTER_OTHER);

#undef __string
#define __string(item, src) __dynamic_array(char, item, -1)

#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, func, print)	\
static int notrace __init						\
ftrace_define_fields_##call(struct ftrace_event_call *event_call)	\
{									\
	struct ftrace_raw_##call field;					\
	int ret;							\
									\
	tstruct;							\
									\
	return ret;							\
}

#undef DEFINE_EVENT
#define DEFINE_EVENT(template, name, proto, args)

#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))

#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)

/*
 * remember the offset of each array from the beginning of the event.
 */

#undef __entry
#define __entry entry

#undef __field
#define __field(type, item)

#undef __field_ext
#define __field_ext(type, item, filter_type)

#undef __array
#define __array(type, item, len)

#undef __dynamic_array
#define __dynamic_array(type, item, len)				\
	__item_length = (len) * sizeof(type);				\
	__data_offsets->item = __data_size +				\
			       offsetof(typeof(*entry), __data);	\
	__data_offsets->item |= __item_length << 16;			\
	__data_size += __item_length;

#undef __string
#define __string(item, src) __dynamic_array(char, item,			\
		    strlen((src) ? (const char *)(src) : "(null)") + 1)

#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
static inline notrace int ftrace_get_offsets_##call(			\
	struct ftrace_data_offsets_##call *__data_offsets, proto)       \
{									\
	int __data_size = 0;						\
	int __maybe_unused __item_length;				\
	struct ftrace_raw_##call __maybe_unused *entry;			\
									\
	tstruct;							\
									\
	return __data_size;						\
}

#undef DEFINE_EVENT
#define DEFINE_EVENT(template, name, proto, args)

#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))

#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)

/*
 * Stage 4 of the trace events.
 *
 * Override the macros in <trace/trace_events.h> to include the following:
 *
 * For those macros defined with TRACE_EVENT:
 *
 * static struct ftrace_event_call event_<call>;
 *
 * static void ftrace_raw_event_<call>(void *__data, proto)
 * {
 *	struct ftrace_event_file *ftrace_file = __data;
 *	struct ftrace_event_call *event_call = ftrace_file->event_call;
 *	struct ftrace_data_offsets_<call> __maybe_unused __data_offsets;
 *	unsigned long eflags = ftrace_file->flags;
 *	enum event_trigger_type __tt = ETT_NONE;
 *	struct ring_buffer_event *event;
 *	struct ftrace_raw_<call> *entry; <-- defined in stage 1
 *	struct ring_buffer *buffer;
 *	unsigned long irq_flags;
 *	int __data_size;
 *	int pc;
 *
 *	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
 *		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
 *			event_triggers_call(ftrace_file, NULL);
 *		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
 *			return;
 *	}
 *
 *	local_save_flags(irq_flags);
 *	pc = preempt_count();
 *
 *	__data_size = ftrace_get_offsets_<call>(&__data_offsets, args);
 *
 *	event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
 *				  event_<call>->event.type,
 *				  sizeof(*entry) + __data_size,
 *				  irq_flags, pc);
 *	if (!event)
 *		return;
 *	entry	= ring_buffer_event_data(event);
 *
 *	{ <assign>; }  <-- Here we assign the entries by the __field and
 *			   __array macros.
 *
 *	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
 *		__tt = event_triggers_call(ftrace_file, entry);
 *
 *	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT,
 *		     &ftrace_file->flags))
 *		ring_buffer_discard_commit(buffer, event);
 *	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
 *		trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
 *
 *	if (__tt)
 *		event_triggers_post_call(ftrace_file, __tt);
 * }
 *
 * static struct trace_event ftrace_event_type_<call> = {
 *	.trace			= ftrace_raw_output_<call>, <-- stage 2
 * };
 *
 * static const char print_fmt_<call>[] = <TP_printk>;
 *
 * static struct ftrace_event_class __used event_class_<template> = {
 *	.system			= "<system>",
 *	.define_fields		= ftrace_define_fields_<call>,
 *	.fields			= LIST_HEAD_INIT(event_class_##call.fields),
 *	.raw_init		= trace_event_raw_init,
 *	.probe			= ftrace_raw_event_##call,
 *	.reg			= ftrace_event_reg,
 * };
 *
 * static struct ftrace_event_call event_<call> = {
 *	.class			= event_class_<template>,
 *	{
 *		.tp			= &__tracepoint_<call>,
 *	},
 *	.event			= &ftrace_event_type_<call>,
 *	.print_fmt		= print_fmt_<call>,
 *	.flags			= TRACE_EVENT_FL_TRACEPOINT,
 * };
 * // its only safe to use pointers when doing linker tricks to
 * // create an array.
 * static struct ftrace_event_call __used
 * __attribute__((section("_ftrace_events"))) *__event_<call> = &event_<call>;
 *
 */

#ifdef CONFIG_PERF_EVENTS

#define _TRACE_PERF_PROTO(call, proto)					\
	static notrace void						\
	perf_trace_##call(void *__data, proto);

#define _TRACE_PERF_INIT(call)						\
	.perf_probe		= perf_trace_##call,

#else
#define _TRACE_PERF_PROTO(call, proto)
#define _TRACE_PERF_INIT(call)
#endif /* CONFIG_PERF_EVENTS */

#undef __entry
#define __entry entry

#undef __field
#define __field(type, item)

#undef __array
#define __array(type, item, len)

#undef __dynamic_array
#define __dynamic_array(type, item, len)				\
	__entry->__data_loc_##item = __data_offsets.item;

#undef __string
#define __string(item, src) __dynamic_array(char, item, -1)       	\

#undef __assign_str
#define __assign_str(dst, src)						\
	strcpy(__get_str(dst), (src) ? (const char *)(src) : "(null)");

#undef TP_fast_assign
#define TP_fast_assign(args...) args

#undef __perf_addr
#define __perf_addr(a)	(a)

#undef __perf_count
#define __perf_count(c)	(c)

#undef __perf_task
#define __perf_task(t)	(t)

#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
									\
static notrace void							\
ftrace_raw_event_##call(void *__data, proto)				\
{									\
	struct ftrace_event_file *ftrace_file = __data;			\
	struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\
	struct ftrace_event_buffer fbuffer;				\
	struct ftrace_raw_##call *entry;				\
	int __data_size;						\
									\
	if (ftrace_trigger_soft_disabled(ftrace_file))			\
		return;							\
									\
	__data_size = ftrace_get_offsets_##call(&__data_offsets, args); \
									\
	entry = ftrace_event_buffer_reserve(&fbuffer, ftrace_file,	\
				 sizeof(*entry) + __data_size);		\
									\
	if (!entry)							\
		return;							\
									\
	tstruct								\
									\
	{ assign; }							\
									\
	ftrace_event_buffer_commit(&fbuffer);				\
}
/*
 * The ftrace_test_probe is compiled out, it is only here as a build time check
 * to make sure that if the tracepoint handling changes, the ftrace probe will
 * fail to compile unless it too is updated.
 */

#undef DEFINE_EVENT
#define DEFINE_EVENT(template, call, proto, args)			\
static inline void ftrace_test_probe_##call(void)			\
{									\
	check_trace_callback_type_##call(ftrace_raw_event_##template);	\
}

#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print)

#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)

#undef __entry
#define __entry REC

#undef __print_flags
#undef __print_symbolic
#undef __print_hex
#undef __get_dynamic_array
#undef __get_str

#undef TP_printk
#define TP_printk(fmt, args...) "\"" fmt "\", "  __stringify(args)

#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
_TRACE_PERF_PROTO(call, PARAMS(proto));					\
static const char print_fmt_##call[] = print;				\
static struct ftrace_event_class __used __refdata event_class_##call = { \
	.system			= __stringify(TRACE_SYSTEM),		\
	.define_fields		= ftrace_define_fields_##call,		\
	.fields			= LIST_HEAD_INIT(event_class_##call.fields),\
	.raw_init		= trace_event_raw_init,			\
	.probe			= ftrace_raw_event_##call,		\
	.reg			= ftrace_event_reg,			\
	_TRACE_PERF_INIT(call)						\
};

#undef DEFINE_EVENT
#define DEFINE_EVENT(template, call, proto, args)			\
									\
static struct ftrace_event_call __used event_##call = {			\
	.class			= &event_class_##template,		\
	{								\
		.tp			= &__tracepoint_##call,		\
	},								\
	.event.funcs		= &ftrace_event_type_funcs_##template,	\
	.print_fmt		= print_fmt_##template,			\
	.flags			= TRACE_EVENT_FL_TRACEPOINT,		\
};									\
static struct ftrace_event_call __used					\
__attribute__((section("_ftrace_events"))) *__event_##call = &event_##call

#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, call, proto, args, print)		\
									\
static const char print_fmt_##call[] = print;				\
									\
static struct ftrace_event_call __used event_##call = {			\
	.class			= &event_class_##template,		\
	{								\
		.tp			= &__tracepoint_##call,		\
	},								\
	.event.funcs		= &ftrace_event_type_funcs_##call,	\
	.print_fmt		= print_fmt_##call,			\
	.flags			= TRACE_EVENT_FL_TRACEPOINT,		\
};									\
static struct ftrace_event_call __used					\
__attribute__((section("_ftrace_events"))) *__event_##call = &event_##call

#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)


#ifdef CONFIG_PERF_EVENTS

#undef __entry
#define __entry entry

#undef __get_dynamic_array
#define __get_dynamic_array(field)	\
		((void *)__entry + (__entry->__data_loc_##field & 0xffff))

#undef __get_str
#define __get_str(field) (char *)__get_dynamic_array(field)

#undef __perf_addr
#define __perf_addr(a)	(__addr = (a))

#undef __perf_count
#define __perf_count(c)	(__count = (c))

#undef __perf_task
#define __perf_task(t)	(__task = (t))

#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
static notrace void							\
perf_trace_##call(void *__data, proto)					\
{									\
	struct ftrace_event_call *event_call = __data;			\
	struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\
	struct ftrace_raw_##call *entry;				\
	struct pt_regs __regs;						\
	u64 __addr = 0, __count = 1;					\
	struct task_struct *__task = NULL;				\
	struct hlist_head *head;					\
	int __entry_size;						\
	int __data_size;						\
	int rctx;							\
									\
	__data_size = ftrace_get_offsets_##call(&__data_offsets, args); \
									\
	head = this_cpu_ptr(event_call->perf_events);			\
	if (__builtin_constant_p(!__task) && !__task &&			\
				hlist_empty(head))			\
		return;							\
									\
	__entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\
			     sizeof(u64));				\
	__entry_size -= sizeof(u32);					\
									\
	perf_fetch_caller_regs(&__regs);				\
	entry = perf_trace_buf_prepare(__entry_size,			\
			event_call->event.type, &__regs, &rctx);	\
	if (!entry)							\
		return;							\
									\
	tstruct								\
									\
	{ assign; }							\
									\
	perf_trace_buf_submit(entry, __entry_size, rctx, __addr,	\
		__count, &__regs, head, __task);			\
}

/*
 * This part is compiled out, it is only here as a build time check
 * to make sure that if the tracepoint handling changes, the
 * perf probe will fail to compile unless it too is updated.
 */
#undef DEFINE_EVENT
#define DEFINE_EVENT(template, call, proto, args)			\
static inline void perf_test_probe_##call(void)				\
{									\
	check_trace_callback_type_##call(perf_trace_##template);	\
}


#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))

#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
#endif /* CONFIG_PERF_EVENTS */