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| | #define _GNU_SOURCE
#include <stdlib.h>
#include <errno.h>
#include <sched.h>
#include "syscall.h"
#include "atomic.h"
#ifdef VDSO_GETCPU_SYM
void *__vdsosym(const char *, const char *);
static void *volatile vdso_func;
typedef long (*getcpu_f)(unsigned *, unsigned *, void *);
long getcpu_init(unsigned *cpu, unsigned *node, void *unused)
{
void *p = __vdsosym(VDSO_GETCPU_VER, VDSO_GETCPU_SYM);
getcpu_f f = (getcpu_f)p;
a_cas_p(&vdso_func, (void *)getcpu_init, p);
return f ? f(cpu, node, unused) : -ENOSYS;
}
static void *volatile vdso_func = (void *)getcpu_init;
#endif
int sched_getcpu(void)
{
int r;
unsigned cpu;
#ifdef VDSO_CGT_SYM
getcpu_f f = (getcpu_f)vdso_func;
if (f) {
r = f(&cpu, NULL, NULL);
if (!r) return cpu;
if (r != -ENOSYS) return __syscall_ret(r);
}
#endif
r = __syscall(SYS_getcpu, &cpu, NULL, NULL);
if (!r) return cpu;
return __syscall_ret(r);
}
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