1// SPDX-License-Identifier: GPL-2.0
2#include <linux/export.h>
3#include <linux/percpu.h>
4#include <linux/preempt.h>
5#include <asm/msr.h>
6#define CREATE_TRACE_POINTS
7#include <asm/msr-trace.h>
8
9struct msr *msrs_alloc(void)
10{
11 struct msr *msrs = NULL;
12
13 msrs = alloc_percpu(struct msr);
14 if (!msrs) {
15 pr_warn("%s: error allocating msrs\n", __func__);
16 return NULL;
17 }
18
19 return msrs;
20}
21EXPORT_SYMBOL(msrs_alloc);
22
23void msrs_free(struct msr *msrs)
24{
25 free_percpu(msrs);
26}
27EXPORT_SYMBOL(msrs_free);
28
29/**
30 * Read an MSR with error handling
31 *
32 * @msr: MSR to read
33 * @m: value to read into
34 *
35 * It returns read data only on success, otherwise it doesn't change the output
36 * argument @m.
37 *
38 */
39int msr_read(u32 msr, struct msr *m)
40{
41 int err;
42 u64 val;
43
44 err = rdmsrl_safe(msr, &val);
45 if (!err)
46 m->q = val;
47
48 return err;
49}
50
51/**
52 * Write an MSR with error handling
53 *
54 * @msr: MSR to write
55 * @m: value to write
56 */
57int msr_write(u32 msr, struct msr *m)
58{
59 return wrmsrl_safe(msr, m->q);
60}
61
62static inline int __flip_bit(u32 msr, u8 bit, bool set)
63{
64 struct msr m, m1;
65 int err = -EINVAL;
66
67 if (bit > 63)
68 return err;
69
70 err = msr_read(msr, &m);
71 if (err)
72 return err;
73
74 m1 = m;
75 if (set)
76 m1.q |= BIT_64(bit);
77 else
78 m1.q &= ~BIT_64(bit);
79
80 if (m1.q == m.q)
81 return 0;
82
83 err = msr_write(msr, &m1);
84 if (err)
85 return err;
86
87 return 1;
88}
89
90/**
91 * Set @bit in a MSR @msr.
92 *
93 * Retval:
94 * < 0: An error was encountered.
95 * = 0: Bit was already set.
96 * > 0: Hardware accepted the MSR write.
97 */
98int msr_set_bit(u32 msr, u8 bit)
99{
100 return __flip_bit(msr, bit, true);
101}
102
103/**
104 * Clear @bit in a MSR @msr.
105 *
106 * Retval:
107 * < 0: An error was encountered.
108 * = 0: Bit was already cleared.
109 * > 0: Hardware accepted the MSR write.
110 */
111int msr_clear_bit(u32 msr, u8 bit)
112{
113 return __flip_bit(msr, bit, false);
114}
115
116#ifdef CONFIG_TRACEPOINTS
117void do_trace_write_msr(unsigned int msr, u64 val, int failed)
118{
119 trace_write_msr(msr, val, failed);
120}
121EXPORT_SYMBOL(do_trace_write_msr);
122EXPORT_TRACEPOINT_SYMBOL(write_msr);
123
124void do_trace_read_msr(unsigned int msr, u64 val, int failed)
125{
126 trace_read_msr(msr, val, failed);
127}
128EXPORT_SYMBOL(do_trace_read_msr);
129EXPORT_TRACEPOINT_SYMBOL(read_msr);
130
131void do_trace_rdpmc(unsigned counter, u64 val, int failed)
132{
133 trace_rdpmc(counter, val, failed);
134}
135EXPORT_SYMBOL(do_trace_rdpmc);
136EXPORT_TRACEPOINT_SYMBOL(rdpmc);
137
138#endif
139