1// SPDX-License-Identifier: GPL-2.0
2#include <linux/export.h>
3#include <linux/preempt.h>
4#include <linux/smp.h>
5#include <linux/completion.h>
6#include <asm/msr.h>
7
8static void __rdmsr_on_cpu(void *info)
9{
10 struct msr_info *rv = info;
11 struct msr *reg;
12 int this_cpu = raw_smp_processor_id();
13
14 if (rv->msrs)
15 reg = per_cpu_ptr(rv->msrs, this_cpu);
16 else
17 reg = &rv->reg;
18
19 rdmsr(rv->msr_no, reg->l, reg->h);
20}
21
22static void __wrmsr_on_cpu(void *info)
23{
24 struct msr_info *rv = info;
25 struct msr *reg;
26 int this_cpu = raw_smp_processor_id();
27
28 if (rv->msrs)
29 reg = per_cpu_ptr(rv->msrs, this_cpu);
30 else
31 reg = &rv->reg;
32
33 wrmsr(rv->msr_no, reg->l, reg->h);
34}
35
36int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
37{
38 int err;
39 struct msr_info rv;
40
41 memset(&rv, 0, sizeof(rv));
42
43 rv.msr_no = msr_no;
44 err = smp_call_function_single(cpuid: cpu, func: __rdmsr_on_cpu, info: &rv, wait: 1);
45 *l = rv.reg.l;
46 *h = rv.reg.h;
47
48 return err;
49}
50EXPORT_SYMBOL(rdmsr_on_cpu);
51
52int rdmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
53{
54 int err;
55 struct msr_info rv;
56
57 memset(&rv, 0, sizeof(rv));
58
59 rv.msr_no = msr_no;
60 err = smp_call_function_single(cpuid: cpu, func: __rdmsr_on_cpu, info: &rv, wait: 1);
61 *q = rv.reg.q;
62
63 return err;
64}
65EXPORT_SYMBOL(rdmsrl_on_cpu);
66
67int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
68{
69 int err;
70 struct msr_info rv;
71
72 memset(&rv, 0, sizeof(rv));
73
74 rv.msr_no = msr_no;
75 rv.reg.l = l;
76 rv.reg.h = h;
77 err = smp_call_function_single(cpuid: cpu, func: __wrmsr_on_cpu, info: &rv, wait: 1);
78
79 return err;
80}
81EXPORT_SYMBOL(wrmsr_on_cpu);
82
83int wrmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
84{
85 int err;
86 struct msr_info rv;
87
88 memset(&rv, 0, sizeof(rv));
89
90 rv.msr_no = msr_no;
91 rv.reg.q = q;
92
93 err = smp_call_function_single(cpuid: cpu, func: __wrmsr_on_cpu, info: &rv, wait: 1);
94
95 return err;
96}
97EXPORT_SYMBOL(wrmsrl_on_cpu);
98
99static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no,
100 struct msr *msrs,
101 void (*msr_func) (void *info))
102{
103 struct msr_info rv;
104 int this_cpu;
105
106 memset(&rv, 0, sizeof(rv));
107
108 rv.msrs = msrs;
109 rv.msr_no = msr_no;
110
111 this_cpu = get_cpu();
112
113 if (cpumask_test_cpu(cpu: this_cpu, cpumask: mask))
114 msr_func(&rv);
115
116 smp_call_function_many(mask, func: msr_func, info: &rv, wait: 1);
117 put_cpu();
118}
119
120/* rdmsr on a bunch of CPUs
121 *
122 * @mask: which CPUs
123 * @msr_no: which MSR
124 * @msrs: array of MSR values
125 *
126 */
127void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs)
128{
129 __rwmsr_on_cpus(mask, msr_no, msrs, msr_func: __rdmsr_on_cpu);
130}
131EXPORT_SYMBOL(rdmsr_on_cpus);
132
133/*
134 * wrmsr on a bunch of CPUs
135 *
136 * @mask: which CPUs
137 * @msr_no: which MSR
138 * @msrs: array of MSR values
139 *
140 */
141void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs)
142{
143 __rwmsr_on_cpus(mask, msr_no, msrs, msr_func: __wrmsr_on_cpu);
144}
145EXPORT_SYMBOL(wrmsr_on_cpus);
146
147struct msr_info_completion {
148 struct msr_info msr;
149 struct completion done;
150};
151
152/* These "safe" variants are slower and should be used when the target MSR
153 may not actually exist. */
154static void __rdmsr_safe_on_cpu(void *info)
155{
156 struct msr_info_completion *rv = info;
157
158 rv->msr.err = rdmsr_safe(rv->msr.msr_no, &rv->msr.reg.l, &rv->msr.reg.h);
159 complete(&rv->done);
160}
161
162static void __wrmsr_safe_on_cpu(void *info)
163{
164 struct msr_info *rv = info;
165
166 rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
167}
168
169int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
170{
171 struct msr_info_completion rv;
172 call_single_data_t csd;
173 int err;
174
175 INIT_CSD(&csd, __rdmsr_safe_on_cpu, &rv);
176
177 memset(&rv, 0, sizeof(rv));
178 init_completion(x: &rv.done);
179 rv.msr.msr_no = msr_no;
180
181 err = smp_call_function_single_async(cpu, csd: &csd);
182 if (!err) {
183 wait_for_completion(&rv.done);
184 err = rv.msr.err;
185 }
186 *l = rv.msr.reg.l;
187 *h = rv.msr.reg.h;
188
189 return err;
190}
191EXPORT_SYMBOL(rdmsr_safe_on_cpu);
192
193int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
194{
195 int err;
196 struct msr_info rv;
197
198 memset(&rv, 0, sizeof(rv));
199
200 rv.msr_no = msr_no;
201 rv.reg.l = l;
202 rv.reg.h = h;
203 err = smp_call_function_single(cpuid: cpu, func: __wrmsr_safe_on_cpu, info: &rv, wait: 1);
204
205 return err ? err : rv.err;
206}
207EXPORT_SYMBOL(wrmsr_safe_on_cpu);
208
209int wrmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
210{
211 int err;
212 struct msr_info rv;
213
214 memset(&rv, 0, sizeof(rv));
215
216 rv.msr_no = msr_no;
217 rv.reg.q = q;
218
219 err = smp_call_function_single(cpuid: cpu, func: __wrmsr_safe_on_cpu, info: &rv, wait: 1);
220
221 return err ? err : rv.err;
222}
223EXPORT_SYMBOL(wrmsrl_safe_on_cpu);
224
225int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
226{
227 u32 low, high;
228 int err;
229
230 err = rdmsr_safe_on_cpu(cpu, msr_no, &low, &high);
231 *q = (u64)high << 32 | low;
232
233 return err;
234}
235EXPORT_SYMBOL(rdmsrl_safe_on_cpu);
236
237/*
238 * These variants are significantly slower, but allows control over
239 * the entire 32-bit GPR set.
240 */
241static void __rdmsr_safe_regs_on_cpu(void *info)
242{
243 struct msr_regs_info *rv = info;
244
245 rv->err = rdmsr_safe_regs(regs: rv->regs);
246}
247
248static void __wrmsr_safe_regs_on_cpu(void *info)
249{
250 struct msr_regs_info *rv = info;
251
252 rv->err = wrmsr_safe_regs(regs: rv->regs);
253}
254
255int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
256{
257 int err;
258 struct msr_regs_info rv;
259
260 rv.regs = regs;
261 rv.err = -EIO;
262 err = smp_call_function_single(cpuid: cpu, func: __rdmsr_safe_regs_on_cpu, info: &rv, wait: 1);
263
264 return err ? err : rv.err;
265}
266EXPORT_SYMBOL(rdmsr_safe_regs_on_cpu);
267
268int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
269{
270 int err;
271 struct msr_regs_info rv;
272
273 rv.regs = regs;
274 rv.err = -EIO;
275 err = smp_call_function_single(cpuid: cpu, func: __wrmsr_safe_regs_on_cpu, info: &rv, wait: 1);
276
277 return err ? err : rv.err;
278}
279EXPORT_SYMBOL(wrmsr_safe_regs_on_cpu);
280

source code of linux/arch/x86/lib/msr-smp.c