arch/x86/lib/msr.c

   1 #include <linux/module.h>
   2 #include <linux/preempt.h>
   3 #include <linux/smp.h>
   4 #include <asm/msr.h>
   5
   6 struct msr_info {
   7         u32 msr_no;
   8         struct msr reg;
   9         struct msr *msrs;
  10         int off;
  11         int err;
  12 };
  13
  14 static void __rdmsr_on_cpu(void *info)
  15 {
  16         struct msr_info *rv = info;
  17         struct msr *reg;
  18         int this_cpu = raw_smp_processor_id();
  19
  20         if (rv->msrs)
  21                 reg = &rv->msrs[this_cpu - rv->off];
  22         else
  23                 reg = &rv->reg;
  24
  25         rdmsr(rv->msr_no, reg->l, reg->h);
  26 }
  27
  28 static void __wrmsr_on_cpu(void *info)
  29 {
  30         struct msr_info *rv = info;
  31         struct msr *reg;
  32         int this_cpu = raw_smp_processor_id();
  33
  34         if (rv->msrs)
  35                 reg = &rv->msrs[this_cpu - rv->off];
  36         else
  37                 reg = &rv->reg;
  38
  39         wrmsr(rv->msr_no, reg->l, reg->h);
  40 }
  41
  42 int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
  43 {
  44         int err;
  45         struct msr_info rv;
  46
  47         memset(&rv, 0, sizeof(rv));
  48
  49         rv.msr_no = msr_no;
  50         err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
  51         *l = rv.reg.l;
  52         *h = rv.reg.h;
  53
  54         return err;
  55 }
  56 EXPORT_SYMBOL(rdmsr_on_cpu);
  57
  58 int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
  59 {
  60         int err;
  61         struct msr_info rv;
  62
  63         memset(&rv, 0, sizeof(rv));
  64
  65         rv.msr_no = msr_no;
  66         rv.reg.l = l;
  67         rv.reg.h = h;
  68         err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
  69
  70         return err;
  71 }
  72 EXPORT_SYMBOL(wrmsr_on_cpu);
  73
  74 /* rdmsr on a bunch of CPUs
  75  *
  76  * @mask:       which CPUs
  77  * @msr_no:     which MSR
  78  * @msrs:       array of MSR values
  79  *
  80  */
  81 void rdmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
  82 {
  83         struct msr_info rv;
  84         int this_cpu;
  85
  86         memset(&rv, 0, sizeof(rv));
  87
  88         rv.off    = cpumask_first(mask);
  89         rv.msrs   = msrs;
  90         rv.msr_no = msr_no;
  91
  92         this_cpu = get_cpu();
  93
  94         if (cpumask_test_cpu(this_cpu, mask))
  95                 __rdmsr_on_cpu(&rv);
  96
  97         smp_call_function_many(mask, __rdmsr_on_cpu, &rv, 1);
  98         put_cpu();
  99 }
 100 EXPORT_SYMBOL(rdmsr_on_cpus);
 101
 102 /*
 103  * wrmsr on a bunch of CPUs
 104  *
 105  * @mask:       which CPUs
 106  * @msr_no:     which MSR
 107  * @msrs:       array of MSR values
 108  *
 109  */
 110 void wrmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
 111 {
 112         struct msr_info rv;
 113         int this_cpu;
 114
 115         memset(&rv, 0, sizeof(rv));
 116
 117         rv.off    = cpumask_first(mask);
 118         rv.msrs   = msrs;
 119         rv.msr_no = msr_no;
 120
 121         this_cpu = get_cpu();
 122
 123         if (cpumask_test_cpu(this_cpu, mask))
 124                 __wrmsr_on_cpu(&rv);
 125
 126         smp_call_function_many(mask, __wrmsr_on_cpu, &rv, 1);
 127         put_cpu();
 128 }
 129 EXPORT_SYMBOL(wrmsr_on_cpus);
 130
 131 /* These "safe" variants are slower and should be used when the target MSR
 132    may not actually exist. */
 133 static void __rdmsr_safe_on_cpu(void *info)
 134 {
 135         struct msr_info *rv = info;
 136
 137         rv->err = rdmsr_safe(rv->msr_no, &rv->reg.l, &rv->reg.h);
 138 }
 139
 140 static void __wrmsr_safe_on_cpu(void *info)
 141 {
 142         struct msr_info *rv = info;
 143
 144         rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
 145 }
 146
 147 int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
 148 {
 149         int err;
 150         struct msr_info rv;
 151
 152         memset(&rv, 0, sizeof(rv));
 153
 154         rv.msr_no = msr_no;
 155         err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1);
 156         *l = rv.reg.l;
 157         *h = rv.reg.h;
 158
 159         return err ? err : rv.err;
 160 }
 161 EXPORT_SYMBOL(rdmsr_safe_on_cpu);
 162
 163 int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
 164 {
 165         int err;
 166         struct msr_info rv;
 167
 168         memset(&rv, 0, sizeof(rv));
 169
 170         rv.msr_no = msr_no;
 171         rv.reg.l = l;
 172         rv.reg.h = h;
 173         err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);
 174
 175         return err ? err : rv.err;
 176 }
 177 EXPORT_SYMBOL(wrmsr_safe_on_cpu);