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 *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 }
21 EXPORT_SYMBOL(msrs_alloc);
22
msrs_free(struct msr * msrs)23 void msrs_free(struct msr *msrs)
24 {
25 free_percpu(msrs);
26 }
27 EXPORT_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 */
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 * Write an MSR with error handling
53 *
54 * @msr: MSR to write
55 * @m: value to write
56 */
msr_write(u32 msr,struct msr * m)57 static int msr_write(u32 msr, struct msr *m)
58 {
59 return wrmsrl_safe(msr, m->q);
60 }
61
__flip_bit(u32 msr,u8 bit,bool set)62 static 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 */
msr_set_bit(u32 msr,u8 bit)98 int 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 */
msr_clear_bit(u32 msr,u8 bit)111 int msr_clear_bit(u32 msr, u8 bit)
112 {
113 return __flip_bit(msr, bit, false);
114 }
115
116 #ifdef CONFIG_TRACEPOINTS
do_trace_write_msr(unsigned int msr,u64 val,int failed)117 void do_trace_write_msr(unsigned int msr, u64 val, int failed)
118 {
119 trace_write_msr(msr, val, failed);
120 }
121 EXPORT_SYMBOL(do_trace_write_msr);
122 EXPORT_TRACEPOINT_SYMBOL(write_msr);
123
do_trace_read_msr(unsigned int msr,u64 val,int failed)124 void do_trace_read_msr(unsigned int msr, u64 val, int failed)
125 {
126 trace_read_msr(msr, val, failed);
127 }
128 EXPORT_SYMBOL(do_trace_read_msr);
129 EXPORT_TRACEPOINT_SYMBOL(read_msr);
130
do_trace_rdpmc(unsigned counter,u64 val,int failed)131 void do_trace_rdpmc(unsigned counter, u64 val, int failed)
132 {
133 trace_rdpmc(counter, val, failed);
134 }
135 EXPORT_SYMBOL(do_trace_rdpmc);
136 EXPORT_TRACEPOINT_SYMBOL(rdpmc);
137
138 #endif
139