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Viewing changes to arch/x86/vdso/vgetcpu.c

  • Committer: Package Import Robot
  • Author(s): Alessio Igor Bogani
  • Date: 2011-10-26 11:13:05 UTC
  • Revision ID: package-import@ubuntu.com-20111026111305-tz023xykf0i6eosh
Tags: upstream-3.2.0
Import upstream version 3.2.0

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arch/x86/vdso/vgetcpu.c
 
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/*
 
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 * Copyright 2006 Andi Kleen, SUSE Labs.
 
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 * Subject to the GNU Public License, v.2
 
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 *
 
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 * Fast user context implementation of getcpu()
 
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 */
 
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#include <linux/kernel.h>
 
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#include <linux/getcpu.h>
 
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#include <linux/jiffies.h>
 
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#include <linux/time.h>
 
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#include <asm/vsyscall.h>
 
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#include <asm/vgtod.h>
 
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notrace long
 
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__vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
 
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{
 
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        unsigned int p;
 
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        if (VVAR(vgetcpu_mode) == VGETCPU_RDTSCP) {
 
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                /* Load per CPU data from RDTSCP */
 
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                native_read_tscp(&p);
 
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        } else {
 
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                /* Load per CPU data from GDT */
 
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                asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
 
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        }
 
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        if (cpu)
 
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                *cpu = p & 0xfff;
 
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        if (node)
 
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                *node = p >> 12;
 
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        return 0;
 
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}
 
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long getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
 
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        __attribute__((weak, alias("__vdso_getcpu")));