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 __percpu *msrs_alloc(void)
10{
11 struct msr __percpu *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 __percpu *msrs)
24{
25 free_percpu(pdata: msrs);
26}
27EXPORT_SYMBOL(msrs_free);
28
29/**
30 * msr_read - Read an MSR with error handling
31 * @msr: MSR to read
32 * @m: value to read into
33 *
34 * It returns read data only on success, otherwise it doesn't change the output
35 * argument @m.
36 *
37 * Return: %0 for success, otherwise an error code
38 */
39static int msr_read(u32 msr, struct msr *m)
40{
41 int err;
42 u64 val;
43
44 err = rdmsrq_safe(msr, p: &val);
45 if (!err)
46 m->q = val;
47
48 return err;
49}
50
51/**
52 * msr_write - Write an MSR with error handling
53 *
54 * @msr: MSR to write
55 * @m: value to write
56 *
57 * Return: %0 for success, otherwise an error code
58 */
59static int msr_write(u32 msr, struct msr *m)
60{
61 return wrmsrq_safe(msr, val: m->q);
62}
63
64static inline int __flip_bit(u32 msr, u8 bit, bool set)
65{
66 struct msr m, m1;
67 int err = -EINVAL;
68
69 if (bit > 63)
70 return err;
71
72 err = msr_read(msr, m: &m);
73 if (err)
74 return err;
75
76 m1 = m;
77 if (set)
78 m1.q |= BIT_64(bit);
79 else
80 m1.q &= ~BIT_64(bit);
81
82 if (m1.q == m.q)
83 return 0;
84
85 err = msr_write(msr, m: &m1);
86 if (err)
87 return err;
88
89 return 1;
90}
91
92/**
93 * msr_set_bit - Set @bit in a MSR @msr.
94 * @msr: MSR to write
95 * @bit: bit number to set
96 *
97 * Return:
98 * * < 0: An error was encountered.
99 * * = 0: Bit was already set.
100 * * > 0: Hardware accepted the MSR write.
101 */
102int msr_set_bit(u32 msr, u8 bit)
103{
104 return __flip_bit(msr, bit, set: true);
105}
106EXPORT_SYMBOL_GPL(msr_set_bit);
107
108/**
109 * msr_clear_bit - Clear @bit in a MSR @msr.
110 * @msr: MSR to write
111 * @bit: bit number to clear
112 *
113 * Return:
114 * * < 0: An error was encountered.
115 * * = 0: Bit was already cleared.
116 * * > 0: Hardware accepted the MSR write.
117 */
118int msr_clear_bit(u32 msr, u8 bit)
119{
120 return __flip_bit(msr, bit, set: false);
121}
122EXPORT_SYMBOL_GPL(msr_clear_bit);
123
124#ifdef CONFIG_TRACEPOINTS
125void do_trace_write_msr(u32 msr, u64 val, int failed)
126{
127 trace_write_msr(msr, val, failed);
128}
129EXPORT_SYMBOL(do_trace_write_msr);
130EXPORT_TRACEPOINT_SYMBOL(write_msr);
131
132void do_trace_read_msr(u32 msr, u64 val, int failed)
133{
134 trace_read_msr(msr, val, failed);
135}
136EXPORT_SYMBOL(do_trace_read_msr);
137EXPORT_TRACEPOINT_SYMBOL(read_msr);
138
139void do_trace_rdpmc(u32 msr, u64 val, int failed)
140{
141 trace_rdpmc(msr, val, failed);
142}
143EXPORT_SYMBOL(do_trace_rdpmc);
144EXPORT_TRACEPOINT_SYMBOL(rdpmc);
145
146#endif
147