aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/lib/msr.c
blob: cade714e57f9f9af8900065286ea9b0fd74ad7a1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
#include <linux/module.h>
#include <linux/preempt.h>
#include <linux/smp.h>
#include <asm/msr.h>

struct msr_info {
	u32 msr_no;
	struct msr reg;
	int err;
};

static void __rdmsr_on_cpu(void *info)
{
	struct msr_info *rv = info;

	rdmsr(rv->msr_no, rv->reg.l, rv->reg.h);
}

static void __wrmsr_on_cpu(void *info)
{
	struct msr_info *rv = info;

	wrmsr(rv->msr_no, rv->reg.l, rv->reg.h);
}

int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
	int err;
	struct msr_info rv;

	rv.msr_no = msr_no;
	err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
	*l = rv.reg.l;
	*h = rv.reg.h;

	return err;
}

int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
{
	int err;
	struct msr_info rv;

	rv.msr_no = msr_no;
	rv.reg.l = l;
	rv.reg.h = h;
	err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);

	return err;
}

/* These "safe" variants are slower and should be used when the target MSR
   may not actually exist. */
static void __rdmsr_safe_on_cpu(void *info)
{
	struct msr_info *rv = info;

	rv->err = rdmsr_safe(rv->msr_no, &rv->reg.l, &rv->reg.h);
}

static void __wrmsr_safe_on_cpu(void *info)
{
	struct msr_info *rv = info;

	rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
}

int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
	int err;
	struct msr_info rv;

	rv.msr_no = msr_no;
	err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1);
	*l = rv.reg.l;
	*h = rv.reg.h;

	return err ? err : rv.err;
}

int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
{
	int err;
	struct msr_info rv;

	rv.msr_no = msr_no;
	rv.reg.l = l;
	rv.reg.h = h;
	err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);

	return err ? err : rv.err;
}

EXPORT_SYMBOL(rdmsr_on_cpu);
EXPORT_SYMBOL(wrmsr_on_cpu);
EXPORT_SYMBOL(rdmsr_safe_on_cpu);
EXPORT_SYMBOL(wrmsr_safe_on_cpu);