arch/x86/vdso/vgetcpu.c

   1 /*
   2  * Copyright 2006 Andi Kleen, SUSE Labs.
   3  * Subject to the GNU Public License, v.2
   4  *
   5  * Fast user context implementation of getcpu()
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/getcpu.h>
  10 #include <linux/jiffies.h>
  11 #include <linux/time.h>
  12 #include <asm/vsyscall.h>
  13 #include <asm/vgtod.h>
  14
  15 notrace long
  16 __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
  17 {
  18         unsigned int p;
  19
  20         p = __getcpu();
  21
  22         if (cpu)
  23                 *cpu = p & VGETCPU_CPU_MASK;
  24         if (node)
  25                 *node = p >> 12;
  26         return 0;
  27 }
  28
  29 long getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
  30         __attribute__((weak, alias("__vdso_getcpu")));