1 #define _GNU_SOURCE
2 #include <errno.h>
3 #include <sched.h>
4 #include "syscall.h"
5 #include "atomic.h"
6
7 #ifdef VDSO_GETCPU_SYM
8
9 static void *volatile vdso_func;
10
11 typedef long (*getcpu_f)(unsigned *, unsigned *, void *);
12
getcpu_init(unsigned * cpu,unsigned * node,void * unused)13 static long getcpu_init(unsigned *cpu, unsigned *node, void *unused)
14 {
15 #ifndef __LITEOS__
16 __get_vdso_info();
17 void *p = __get_vdso_addr(VDSO_GETCPU_VER, VDSO_GETCPU_SYM);
18 #else
19 void *p = __vdsosym(VDSO_GETCPU_VER, VDSO_GETCPU_SYM);
20 #endif
21 getcpu_f f = (getcpu_f)p;
22 a_cas_p(&vdso_func, (void *)getcpu_init, p);
23 return f ? f(cpu, node, unused) : -ENOSYS;
24 }
25
26 static void *volatile vdso_func = (void *)getcpu_init;
27
28 #endif
29
sched_getcpu(void)30 int sched_getcpu(void)
31 {
32 int r;
33 unsigned cpu;
34
35 #ifdef VDSO_GETCPU_SYM
36 getcpu_f f = (getcpu_f)vdso_func;
37 if (f) {
38 r = f(&cpu, 0, 0);
39 if (!r) return cpu;
40 if (r != -ENOSYS) return __syscall_ret(r);
41 }
42 #endif
43
44 r = __syscall(SYS_getcpu, &cpu, 0, 0);
45 if (!r) return cpu;
46 return __syscall_ret(r);
47 }
48