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linux/include/trace/define_trace.h
Steven Rostedt ac01fa73f5 tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix 
Most tracepoints in the kernel are created with TRACE_EVENT(). The
TRACE_EVENT() macro (and DECLARE_EVENT_CLASS() and DEFINE_EVENT() where in
reality, TRACE_EVENT() is just a helper macro that calls those other two
macros), will create not only a tracepoint (the function trace_<event>()
used in the kernel), it also exposes the tracepoint to user space along
with defining what fields will be saved by that tracepoint.

There are a few places that tracepoints are created in the kernel that are
not exposed to userspace via tracefs. They can only be accessed from code
within the kernel. These tracepoints are created with DEFINE_TRACE()

Most of these tracepoints end with "_tp". This is useful as when the
developer sees that, they know that the tracepoint is for in-kernel only
(meaning it can only be accessed inside the kernel, either directly by the
kernel or indirectly via modules and BPF programs) and is not exposed to
user space.

Instead of making this only a process to add "_tp", enforce it by making
the DECLARE_TRACE() append the "_tp" suffix to the tracepoint. This
requires adding DECLARE_TRACE_EVENT() macros for the TRACE_EVENT() macro
to use that keeps the original name.

Link: https://lore.kernel.org/all/20250418083351.20a60e64@gandalf.local.home/

Cc: netdev <netdev@vger.kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/20250510163730.092fad5b@gandalf.local.home
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-05-14 11:19:32 -04:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Trace files that want to automate creation of all tracepoints defined
* in their file should include this file. The following are macros that the
* trace file may define:
*
* TRACE_SYSTEM defines the system the tracepoint is for
*
* TRACE_INCLUDE_FILE if the file name is something other than TRACE_SYSTEM.h
* This macro may be defined to tell define_trace.h what file to include.
* Note, leave off the ".h".
*
* TRACE_INCLUDE_PATH if the path is something other than core kernel include/trace
* then this macro can define the path to use. Note, the path is relative to
* define_trace.h, not the file including it. Full path names for out of tree
* modules must be used.
*/
#ifdef CREATE_TRACE_POINTS
/* Prevent recursion */
#undef CREATE_TRACE_POINTS
#include <linux/stringify.h>
#undef TRACE_EVENT
#define TRACE_EVENT(name, proto, args, tstruct, assign, print) \
DEFINE_TRACE(name, PARAMS(proto), PARAMS(args))
#undef TRACE_EVENT_CONDITION
#define TRACE_EVENT_CONDITION(name, proto, args, cond, tstruct, assign, print) \
TRACE_EVENT(name, \
PARAMS(proto), \
PARAMS(args), \
PARAMS(tstruct), \
PARAMS(assign), \
PARAMS(print))
#undef TRACE_EVENT_FN
#define TRACE_EVENT_FN(name, proto, args, tstruct, \
assign, print, reg, unreg) \
DEFINE_TRACE_FN(name, reg, unreg, PARAMS(proto), PARAMS(args))
#undef TRACE_EVENT_FN_COND
#define TRACE_EVENT_FN_COND(name, proto, args, cond, tstruct, \
assign, print, reg, unreg) \
DEFINE_TRACE_FN(name, reg, unreg, PARAMS(proto), PARAMS(args))
#undef TRACE_EVENT_SYSCALL
#define TRACE_EVENT_SYSCALL(name, proto, args, struct, assign, print, reg, unreg) \
DEFINE_TRACE_SYSCALL(name, reg, unreg, PARAMS(proto), PARAMS(args))
#undef TRACE_EVENT_NOP
#define TRACE_EVENT_NOP(name, proto, args, struct, assign, print)
#undef DEFINE_EVENT_NOP
#define DEFINE_EVENT_NOP(template, name, proto, args)
#undef DEFINE_EVENT
#define DEFINE_EVENT(template, name, proto, args) \
DEFINE_TRACE(name, PARAMS(proto), PARAMS(args))
#undef DEFINE_EVENT_FN
#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg) \
DEFINE_TRACE_FN(name, reg, unreg, PARAMS(proto), PARAMS(args))
#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
DEFINE_TRACE(name, PARAMS(proto), PARAMS(args))
#undef DEFINE_EVENT_CONDITION
#define DEFINE_EVENT_CONDITION(template, name, proto, args, cond) \
DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
#undef DECLARE_TRACE
#define DECLARE_TRACE(name, proto, args) \
DEFINE_TRACE(name##_tp, PARAMS(proto), PARAMS(args))
#undef DECLARE_TRACE_CONDITION
#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
DEFINE_TRACE(name##_tp, PARAMS(proto), PARAMS(args))
#undef DECLARE_TRACE_EVENT
#define DECLARE_TRACE_EVENT(name, proto, args) \
DEFINE_TRACE(name, PARAMS(proto), PARAMS(args))
#undef DECLARE_TRACE_EVENT_CONDITION
#define DECLARE_TRACE_EVENT_CONDITION(name, proto, args, cond) \
DEFINE_TRACE(name, PARAMS(proto), PARAMS(args))
/* If requested, create helpers for calling these tracepoints from Rust. */
#ifdef CREATE_RUST_TRACE_POINTS
#undef DEFINE_RUST_DO_TRACE
#define DEFINE_RUST_DO_TRACE(name, proto, args) \
__DEFINE_RUST_DO_TRACE(name, PARAMS(proto), PARAMS(args))
#endif
#undef TRACE_INCLUDE
#undef __TRACE_INCLUDE
#ifndef TRACE_INCLUDE_FILE
# define TRACE_INCLUDE_FILE TRACE_SYSTEM
# define UNDEF_TRACE_INCLUDE_FILE
#endif
#ifndef TRACE_INCLUDE_PATH
# define __TRACE_INCLUDE(system) <trace/events/system.h>
# define UNDEF_TRACE_INCLUDE_PATH
#else
# define __TRACE_INCLUDE(system) __stringify(TRACE_INCLUDE_PATH/system.h)
#endif
# define TRACE_INCLUDE(system) __TRACE_INCLUDE(system)
/* Let the trace headers be reread */
#define TRACE_HEADER_MULTI_READ
#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
/* Make all open coded DECLARE_TRACE nops */
#undef DECLARE_TRACE
#define DECLARE_TRACE(name, proto, args)
#undef DECLARE_TRACE_CONDITION
#define DECLARE_TRACE_CONDITION(name, proto, args, cond)
#undef DECLARE_TRACE_EVENT
#define DECLARE_TRACE_EVENT(name, proto, args)
#undef DECLARE_TRACE_EVENT_CONDITION
#define DECLARE_TRACE_EVENT_CONDITION(name, proto, args, cond)
#ifdef TRACEPOINTS_ENABLED
#include <trace/trace_events.h>
#include <trace/perf.h>
#include <trace/bpf_probe.h>
#endif
#undef TRACE_EVENT
#undef TRACE_EVENT_FN
#undef TRACE_EVENT_FN_COND
#undef TRACE_EVENT_SYSCALL
#undef TRACE_EVENT_CONDITION
#undef TRACE_EVENT_NOP
#undef DEFINE_EVENT_NOP
#undef DECLARE_EVENT_CLASS
#undef DEFINE_EVENT
#undef DEFINE_EVENT_FN
#undef DEFINE_EVENT_PRINT
#undef DEFINE_EVENT_CONDITION
#undef TRACE_HEADER_MULTI_READ
#undef DECLARE_TRACE
#undef DECLARE_TRACE_CONDITION
#undef DECLARE_TRACE_EVENT
#undef DECLARE_TRACE_EVENT_CONDITION
/* Only undef what we defined in this file */
#ifdef UNDEF_TRACE_INCLUDE_FILE
# undef TRACE_INCLUDE_FILE
# undef UNDEF_TRACE_INCLUDE_FILE
#endif
#ifdef UNDEF_TRACE_INCLUDE_PATH
# undef TRACE_INCLUDE_PATH
# undef UNDEF_TRACE_INCLUDE_PATH
#endif
#ifdef CREATE_RUST_TRACE_POINTS
# undef DEFINE_RUST_DO_TRACE
# define DEFINE_RUST_DO_TRACE(name, proto, args)
#endif
/* We may be processing more files */
#define CREATE_TRACE_POINTS
#endif /* CREATE_TRACE_POINTS */
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