LXR linux/arch/i386/lib/msr-on-cpu.c

   1#include <linux/module.h>
   2#include <linux/preempt.h>
   3#include <linux/smp.h>
   4#include <asm/msr.h>
   5
   6struct msr_info {
   7        u32 msr_no;
   8        u32 l, h;
   9        int err;
  10};
  11
  12static void __rdmsr_on_cpu(void *info)
  13{
  14        struct msr_info *rv = info;
  15
  16        rdmsr(rv->msr_no, rv->l, rv->h);
  17}
  18
  19static void __rdmsr_safe_on_cpu(void *info)
  20{
  21        struct msr_info *rv = info;
  22
  23        rv->err = rdmsr_safe(rv->msr_no, &rv->l, &rv->h);
  24}
  25
  26static int _rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h, int safe)
  27{
  28        int err = 0;
  29        preempt_disable();
  30        if (smp_processor_id() == cpu)
  31                if (safe)
  32                        err = rdmsr_safe(msr_no, l, h);
  33                else
  34                        rdmsr(msr_no, *l, *h);
  35        else {
  36                struct msr_info rv;
  37
  38                rv.msr_no = msr_no;
  39                if (safe) {
  40                        smp_call_function_single(cpu, __rdmsr_safe_on_cpu,
  41                                                 &rv, 0, 1);
  42                        err = rv.err;
  43                } else {
  44                        smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
  45                }
  46                *l = rv.l;
  47                *h = rv.h;
  48        }
  49        preempt_enable();
  50        return err;
  51}
  52
  53static void __wrmsr_on_cpu(void *info)
  54{
  55        struct msr_info *rv = info;
  56
  57        wrmsr(rv->msr_no, rv->l, rv->h);
  58}
  59
  60static void __wrmsr_safe_on_cpu(void *info)
  61{
  62        struct msr_info *rv = info;
  63
  64        rv->err = wrmsr_safe(rv->msr_no, rv->l, rv->h);
  65}
  66
  67static int _wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h, int safe)
  68{
  69        int err = 0;
  70        preempt_disable();
  71        if (smp_processor_id() == cpu)
  72                if (safe)
  73                        err = wrmsr_safe(msr_no, l, h);
  74                else
  75                        wrmsr(msr_no, l, h);
  76        else {
  77                struct msr_info rv;
  78
  79                rv.msr_no = msr_no;
  80                rv.l = l;
  81                rv.h = h;
  82                if (safe) {
  83                        smp_call_function_single(cpu, __wrmsr_safe_on_cpu,
  84                                                 &rv, 0, 1);
  85                        err = rv.err;
  86                } else {
  87                        smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
  88                }
  89        }
  90        preempt_enable();
  91        return err;
  92}
  93
  94void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
  95{
  96        _wrmsr_on_cpu(cpu, msr_no, l, h, 0);
  97}
  98
  99void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
 100{
 101        _rdmsr_on_cpu(cpu, msr_no, l, h, 0);
 102}
 103
 104/* These "safe" variants are slower and should be used when the target MSR
 105   may not actually exist. */
 106int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
 107{
 108        return _wrmsr_on_cpu(cpu, msr_no, l, h, 1);
 109}
 110
 111int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
 112{
 113        return _rdmsr_on_cpu(cpu, msr_no, l, h, 1);
 114}
 115
 116EXPORT_SYMBOL(rdmsr_on_cpu);
 117EXPORT_SYMBOL(wrmsr_on_cpu);
 118EXPORT_SYMBOL(rdmsr_safe_on_cpu);
 119EXPORT_SYMBOL(wrmsr_safe_on_cpu);
 120