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43 lines
833 B
C
43 lines
833 B
C
#define _GNU_SOURCE
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#include <errno.h>
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#include <sched.h>
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#include "syscall.h"
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#include "atomic.h"
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#ifdef VDSO_GETCPU_SYM
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static void *volatile vdso_func;
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typedef long (*getcpu_f)(unsigned *, unsigned *, void *);
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static long getcpu_init(unsigned *cpu, unsigned *node, void *unused)
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{
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void *p = __vdsosym(VDSO_GETCPU_VER, VDSO_GETCPU_SYM);
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getcpu_f f = (getcpu_f)p;
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a_cas_p(&vdso_func, (void *)getcpu_init, p);
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return f ? f(cpu, node, unused) : -ENOSYS;
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}
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static void *volatile vdso_func = (void *)getcpu_init;
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#endif
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int sched_getcpu(void)
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{
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int r;
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unsigned cpu;
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#ifdef VDSO_GETCPU_SYM
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getcpu_f f = (getcpu_f)vdso_func;
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if (f) {
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r = f(&cpu, 0, 0);
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if (!r) return cpu;
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if (r != -ENOSYS) return __syscall_ret(r);
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}
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#endif
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r = __syscall(SYS_getcpu, &cpu, 0, 0);
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if (!r) return cpu;
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return __syscall_ret(r);
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}
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