#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 DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
static notrace void							\
perf_trace_##call(void *__data, proto)					\
{									\
	struct trace_event_call *event_call = __data;			\
	struct trace_event_data_offsets_##call __maybe_unused __data_offsets;\
	struct trace_event_raw_##call *entry;				\
	struct pt_regs *__regs;						\
	u64 __count = 1;						\
	struct task_struct *__task = NULL;				\
	struct hlist_head *head;					\
	int __entry_size;						\
	int __data_size;						\
	int rctx;							\
									\
	__data_size = trace_event_get_offsets_##call(&__data_offsets, args); \
									\
	head = this_cpu_ptr(event_call->perf_events);			\
	if (!bpf_prog_array_valid(event_call) &&			\
	    __builtin_constant_p(!__task) && !__task &&			\
	    hlist_empty(head))						\
		return;							\
									\
	__entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\
			     sizeof(u64));				\
	__entry_size -= sizeof(u32);					\
									\
	entry = perf_trace_buf_alloc(__entry_size, &__regs, &rctx);	\
	if (!entry)							\
		return;							\
									\
	perf_fetch_caller_regs(__regs);					\
									\
	tstruct								\
									\
	{ assign; }							\
									\
	perf_trace_run_bpf_submit(entry, __entry_size, rctx,		\
				  event_call, __count, __regs,		\
				  head, __task);			\
}

void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
			       struct trace_event_call *call, u64 count,
			       struct pt_regs *regs, struct hlist_head *head,
			       struct task_struct *task)
{
	if (bpf_prog_array_valid(call)) {
		*(struct pt_regs **)raw_data = regs;
		if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
			perf_swevent_put_recursion_context(rctx);
			return;
		}
	}
	perf_tp_event(call->event.type, count, raw_data, size, regs, head,
		      rctx, task);
}
EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);

/**
 * trace_call_bpf - invoke BPF program
 * @call: tracepoint event
 * @ctx: opaque context pointer
 *
 * kprobe handlers execute BPF programs via this helper.
 * Can be used from static tracepoints in the future.
 *
 * Return: BPF programs always return an integer which is interpreted by
 * kprobe handler as:
 * 0 - return from kprobe (event is filtered out)
 * 1 - store kprobe event into ring buffer
 * Other values are reserved and currently alias to 1
 */
unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
{
	unsigned int ret;

	cant_sleep();

	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
		/*
		 * since some bpf program is already running on this cpu,
		 * don't call into another bpf program (same or different)
		 * and don't send kprobe event into ring-buffer,
		 * so return zero here
		 */
		ret = 0;
		goto out;
	}

	/*
	 * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock
	 * to all call sites, we did a bpf_prog_array_valid() there to check
	 * whether call->prog_array is empty or not, which is
	 * a heuristic to speed up execution.
	 *
	 * If bpf_prog_array_valid() fetched prog_array was
	 * non-NULL, we go into trace_call_bpf() and do the actual
	 * proper rcu_dereference() under RCU lock.
	 * If it turns out that prog_array is NULL then, we bail out.
	 * For the opposite, if the bpf_prog_array_valid() fetched pointer
	 * was NULL, you'll skip the prog_array with the risk of missing
	 * out of events when it was updated in between this and the
	 * rcu_dereference() which is accepted risk.
	 */
	ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN);

 out:
	__this_cpu_dec(bpf_prog_active);

	return ret;
}

struct trace_event_call {
	struct list_head	list;
	struct trace_event_class *class;
	union {
		char			*name;
		/* Set TRACE_EVENT_FL_TRACEPOINT flag when using "tp" */
		struct tracepoint	*tp;
	};
	struct trace_event	event;
	char			*print_fmt;
	struct event_filter	*filter;
	void			*mod;
	void			*data;

	/* See the TRACE_EVENT_FL_* flags above */
	int			flags; /* static flags of different events */

#ifdef CONFIG_PERF_EVENTS
	int				perf_refcount;
	struct hlist_head __percpu	*perf_events;
	struct bpf_prog_array __rcu	*prog_array;

	int	(*perf_perm)(struct trace_event_call *,
			     struct perf_event *);
#endif
};