1/* Macros for defining Systemtap <sys/sdt.h> static probe points.
2 Copyright (C) 2012-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#ifndef _STAP_PROBE_H
20#define _STAP_PROBE_H 1
21
22#ifdef USE_STAP_PROBE
23
24# include <sys/sdt.h>
25
26/* Our code uses one macro LIBC_PROBE (name, n, arg1, ..., argn).
27
28 Without USE_STAP_PROBE, that does nothing but evaluates all
29 its arguments (to prevent bit rot, unlike e.g. assert).
30
31 Systemtap's header defines the macros STAP_PROBE (provider, name) and
32 STAP_PROBEn (provider, name, arg1, ..., argn). For "provider" we paste
33 in MODULE_NAME (libc, libpthread, etc.) automagically.
34
35 The format of the arg parameters is discussed here:
36
37 https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
38
39 The precise details of how register names are specified is
40 architecture specific and can be found in the gdb and SystemTap
41 source code. */
42
43# define LIBC_PROBE(name, n, ...) \
44 LIBC_PROBE_1 (MODULE_NAME, name, n, ## __VA_ARGS__)
45
46# define LIBC_PROBE_1(lib, name, n, ...) \
47 STAP_PROBE##n (lib, name, ## __VA_ARGS__)
48
49# define STAP_PROBE0 STAP_PROBE
50
51# define LIBC_PROBE_ASM(name, template) \
52 STAP_PROBE_ASM (MODULE_NAME, name, template)
53
54# define LIBC_PROBE_ASM_OPERANDS STAP_PROBE_ASM_OPERANDS
55
56#else /* Not USE_STAP_PROBE. */
57
58# ifndef __ASSEMBLER__
59/* Evaluate all the arguments and verify that N matches their number. */
60# define LIBC_PROBE(name, n, ...) STAP_PROBE##n (__VA_ARGS__)
61
62# define STAP_PROBE0()
63# define STAP_PROBE1(a1)
64# define STAP_PROBE2(a1, a2)
65# define STAP_PROBE3(a1, a2, a3)
66# define STAP_PROBE4(a1, a2, a3, a4)
67
68# else
69# define LIBC_PROBE(name, n, ...) /* Nothing. */
70# endif
71
72# define LIBC_PROBE_ASM(name, template) /* Nothing. */
73# define LIBC_PROBE_ASM_OPERANDS(n, ...) /* Nothing. */
74
75#endif /* USE_STAP_PROBE. */
76
77#endif /* stap-probe.h */
78