1/* Macros for defining Systemtap <sys/sdt.h> static probe points.
2 Copyright (C) 2012-2020 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 <https://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 <stap-probe-machine.h>
25# include <sys/sdt.h>
26
27/* Our code uses one macro LIBC_PROBE (name, n, arg1, ..., argn).
28
29 Without USE_STAP_PROBE, that does nothing but evaluates all
30 its arguments (to prevent bit rot, unlike e.g. assert).
31
32 Systemtap's header defines the macros STAP_PROBE (provider, name) and
33 STAP_PROBEn (provider, name, arg1, ..., argn). For "provider" we paste
34 in MODULE_NAME (libc, libpthread, etc.) automagically.
35
36 The format of the arg parameters is discussed here:
37
38 https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
39
40 The precise details of how register names are specified is
41 architecture specific and can be found in the gdb and SystemTap
42 source code. */
43
44# define LIBC_PROBE(name, n, ...) \
45 LIBC_PROBE_1 (MODULE_NAME, name, n, ## __VA_ARGS__)
46
47# define LIBC_PROBE_1(lib, name, n, ...) \
48 STAP_PROBE##n (lib, name, ## __VA_ARGS__)
49
50# define STAP_PROBE0 STAP_PROBE
51
52# define LIBC_PROBE_ASM(name, template) \
53 STAP_PROBE_ASM (MODULE_NAME, name, template)
54
55# define LIBC_PROBE_ASM_OPERANDS STAP_PROBE_ASM_OPERANDS
56
57#else /* Not USE_STAP_PROBE. */
58
59# ifndef __ASSEMBLER__
60/* Evaluate all the arguments and verify that N matches their number. */
61# define LIBC_PROBE(name, n, ...) STAP_PROBE##n (__VA_ARGS__)
62
63# define STAP_PROBE0() do {} while (0)
64# define STAP_PROBE1(a1) do {} while (0)
65# define STAP_PROBE2(a1, a2) do {} while (0)
66# define STAP_PROBE3(a1, a2, a3) do {} while (0)
67# define STAP_PROBE4(a1, a2, a3, a4) do {} while (0)
68
69# else
70# define LIBC_PROBE(name, n, ...) /* Nothing. */
71# endif
72
73# define LIBC_PROBE_ASM(name, template) /* Nothing. */
74# define LIBC_PROBE_ASM_OPERANDS(n, ...) /* Nothing. */
75
76#endif /* USE_STAP_PROBE. */
77
78#endif /* stap-probe.h */
79