1 | /* Macros for defining Systemtap <sys/sdt.h> static probe points. |
2 | Copyright (C) 2012-2024 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 | |