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
msrs_alloc(void)9 struct 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 }
21 EXPORT_SYMBOL(msrs_alloc);
22
msrs_free(struct msr __percpu * msrs)23 void msrs_free(struct msr __percpu *msrs)
24 {
25 free_percpu(msrs);
26 }
27 EXPORT_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 */
msr_read(u32 msr,struct msr * m)39 static int 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 * 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 */
msr_write(u32 msr,struct msr * m)59 static int msr_write(u32 msr, struct msr *m)
60 {
61 return wrmsrl_safe(msr, m->q);
62 }
63
__flip_bit(u32 msr,u8 bit,bool set)64 static 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);
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, &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 */
msr_set_bit(u32 msr,u8 bit)102 int msr_set_bit(u32 msr, u8 bit)
103 {
104 return __flip_bit(msr, bit, true);
105 }
106 EXPORT_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 */
msr_clear_bit(u32 msr,u8 bit)118 int msr_clear_bit(u32 msr, u8 bit)
119 {
120 return __flip_bit(msr, bit, false);
121 }
122 EXPORT_SYMBOL_GPL(msr_clear_bit);
123
124 #ifdef CONFIG_TRACEPOINTS
do_trace_write_msr(unsigned int msr,u64 val,int failed)125 void do_trace_write_msr(unsigned int msr, u64 val, int failed)
126 {
127 trace_write_msr(msr, val, failed);
128 }
129 EXPORT_SYMBOL(do_trace_write_msr);
130 EXPORT_TRACEPOINT_SYMBOL(write_msr);
131
do_trace_read_msr(unsigned int msr,u64 val,int failed)132 void do_trace_read_msr(unsigned int msr, u64 val, int failed)
133 {
134 trace_read_msr(msr, val, failed);
135 }
136 EXPORT_SYMBOL(do_trace_read_msr);
137 EXPORT_TRACEPOINT_SYMBOL(read_msr);
138
do_trace_rdpmc(unsigned counter,u64 val,int failed)139 void do_trace_rdpmc(unsigned counter, u64 val, int failed)
140 {
141 trace_rdpmc(counter, val, failed);
142 }
143 EXPORT_SYMBOL(do_trace_rdpmc);
144 EXPORT_TRACEPOINT_SYMBOL(rdpmc);
145
146 #endif
147