tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 struct msr_info rv;
30
31 rv.msr_no = msr_no;
32 if (safe) {
33 smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 0, 1);
34 err = rv.err;
35 } else {
36 smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
37 }
38 *l = rv.l;
39 *h = rv.h;
40
41 return err;
42}
43
44static void __wrmsr_on_cpu(void *info)
45{
46 struct msr_info *rv = info;
47
48 wrmsr(rv->msr_no, rv->l, rv->h);
49}
50
51static void __wrmsr_safe_on_cpu(void *info)
52{
53 struct msr_info *rv = info;
54
55 rv->err = wrmsr_safe(rv->msr_no, rv->l, rv->h);
56}
57
58static int _wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h, int safe)
59{
60 int err = 0;
61 struct msr_info rv;
62
63 rv.msr_no = msr_no;
64 rv.l = l;
65 rv.h = h;
66 if (safe) {
67 smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 0, 1);
68 err = rv.err;
69 } else {
70 smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
71 }
72
73 return err;
74}
75
76void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
77{
78 _wrmsr_on_cpu(cpu, msr_no, l, h, 0);
79}
80
81void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
82{
83 _rdmsr_on_cpu(cpu, msr_no, l, h, 0);
84}
85
86/* These "safe" variants are slower and should be used when the target MSR
87 may not actually exist. */
88int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
89{
90 return _wrmsr_on_cpu(cpu, msr_no, l, h, 1);
91}
92
93int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
94{
95 return _rdmsr_on_cpu(cpu, msr_no, l, h, 1);
96}
97
98EXPORT_SYMBOL(rdmsr_on_cpu);
99EXPORT_SYMBOL(wrmsr_on_cpu);
100EXPORT_SYMBOL(rdmsr_safe_on_cpu);
101EXPORT_SYMBOL(wrmsr_safe_on_cpu);