diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/sched/sched_getcpu.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/sched/sched_getcpu.c b/src/sched/sched_getcpu.c index 760e4d5b..e08cfdf1 100644 --- a/src/sched/sched_getcpu.c +++ b/src/sched/sched_getcpu.c @@ -1,12 +1,43 @@ #define _GNU_SOURCE +#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 *); + +static 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_GETCPU_SYM + getcpu_f f = (getcpu_f)vdso_func; + if (f) { + r = f(&cpu, 0, 0); + if (!r) return cpu; + if (r != -ENOSYS) return __syscall_ret(r); + } +#endif + r = __syscall(SYS_getcpu, &cpu, 0, 0); if (!r) return cpu; return __syscall_ret(r); |