1 /* Copyright (C) 2007-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <errno.h>
19 #include <sched.h>
20 #include <sysdep.h>
21 #include <sysdep-vdso.h>
22
23 static int
vsyscall_sched_getcpu(void)24 vsyscall_sched_getcpu (void)
25 {
26 unsigned int cpu;
27 int r = -1;
28 #ifdef HAVE_GETCPU_VSYSCALL
29 r = INLINE_VSYSCALL (getcpu, 3, &cpu, NULL, NULL);
30 #else
31 r = INLINE_SYSCALL_CALL (getcpu, &cpu, NULL, NULL);
32 #endif
33 return r == -1 ? r : cpu;
34 }
35
36 #ifdef RSEQ_SIG
37 int
sched_getcpu(void)38 sched_getcpu (void)
39 {
40 int cpu_id = THREAD_GETMEM_VOLATILE (THREAD_SELF, rseq_area.cpu_id);
41 return __glibc_likely (cpu_id >= 0) ? cpu_id : vsyscall_sched_getcpu ();
42 }
43 #else /* RSEQ_SIG */
44 int
sched_getcpu(void)45 sched_getcpu (void)
46 {
47 return vsyscall_sched_getcpu ();
48 }
49 #endif /* RSEQ_SIG */
50