Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : #ifndef _ASM_X86_MSR_H
3 : #define _ASM_X86_MSR_H
4 :
5 : #include "msr-index.h"
6 :
7 : #ifndef __ASSEMBLY__
8 :
9 : #include <asm/asm.h>
10 : #include <asm/errno.h>
11 : #include <asm/cpumask.h>
12 : #include <uapi/asm/msr.h>
13 : #include <asm/shared/msr.h>
14 :
15 : struct msr_info {
16 : u32 msr_no;
17 : struct msr reg;
18 : struct msr *msrs;
19 : int err;
20 : };
21 :
22 : struct msr_regs_info {
23 : u32 *regs;
24 : int err;
25 : };
26 :
27 : struct saved_msr {
28 : bool valid;
29 : struct msr_info info;
30 : };
31 :
32 : struct saved_msrs {
33 : unsigned int num;
34 : struct saved_msr *array;
35 : };
36 :
37 : /*
38 : * both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A"
39 : * constraint has different meanings. For i386, "A" means exactly
40 : * edx:eax, while for x86_64 it doesn't mean rdx:rax or edx:eax. Instead,
41 : * it means rax *or* rdx.
42 : */
43 : #ifdef CONFIG_X86_64
44 : /* Using 64-bit values saves one instruction clearing the high half of low */
45 : #define DECLARE_ARGS(val, low, high) unsigned long low, high
46 : #define EAX_EDX_VAL(val, low, high) ((low) | (high) << 32)
47 : #define EAX_EDX_RET(val, low, high) "=a" (low), "=d" (high)
48 : #else
49 : #define DECLARE_ARGS(val, low, high) unsigned long long val
50 : #define EAX_EDX_VAL(val, low, high) (val)
51 : #define EAX_EDX_RET(val, low, high) "=A" (val)
52 : #endif
53 :
54 : /*
55 : * Be very careful with includes. This header is prone to include loops.
56 : */
57 : #include <asm/atomic.h>
58 : #include <linux/tracepoint-defs.h>
59 :
60 : #ifdef CONFIG_TRACEPOINTS
61 : DECLARE_TRACEPOINT(read_msr);
62 : DECLARE_TRACEPOINT(write_msr);
63 : DECLARE_TRACEPOINT(rdpmc);
64 : extern void do_trace_write_msr(unsigned int msr, u64 val, int failed);
65 : extern void do_trace_read_msr(unsigned int msr, u64 val, int failed);
66 : extern void do_trace_rdpmc(unsigned int msr, u64 val, int failed);
67 : #else
68 : static inline void do_trace_write_msr(unsigned int msr, u64 val, int failed) {}
69 : static inline void do_trace_read_msr(unsigned int msr, u64 val, int failed) {}
70 : static inline void do_trace_rdpmc(unsigned int msr, u64 val, int failed) {}
71 : #endif
72 :
73 : /*
74 : * __rdmsr() and __wrmsr() are the two primitives which are the bare minimum MSR
75 : * accessors and should not have any tracing or other functionality piggybacking
76 : * on them - those are *purely* for accessing MSRs and nothing more. So don't even
77 : * think of extending them - you will be slapped with a stinking trout or a frozen
78 : * shark will reach you, wherever you are! You've been warned.
79 : */
80 : static __always_inline unsigned long long __rdmsr(unsigned int msr)
81 : {
82 : DECLARE_ARGS(val, low, high);
83 :
84 : asm volatile("1: rdmsr\n"
85 : "2:\n"
86 : _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_RDMSR)
87 : : EAX_EDX_RET(val, low, high) : "c" (msr));
88 :
89 : return EAX_EDX_VAL(val, low, high);
90 : }
91 :
92 : static __always_inline void __wrmsr(unsigned int msr, u32 low, u32 high)
93 : {
94 : asm volatile("1: wrmsr\n"
95 : "2:\n"
96 : _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_WRMSR)
97 : : : "c" (msr), "a"(low), "d" (high) : "memory");
98 : }
99 :
100 : #define native_rdmsr(msr, val1, val2) \
101 : do { \
102 : u64 __val = __rdmsr((msr)); \
103 : (void)((val1) = (u32)__val); \
104 : (void)((val2) = (u32)(__val >> 32)); \
105 : } while (0)
106 :
107 : #define native_wrmsr(msr, low, high) \
108 : __wrmsr(msr, low, high)
109 :
110 : #define native_wrmsrl(msr, val) \
111 : __wrmsr((msr), (u32)((u64)(val)), \
112 : (u32)((u64)(val) >> 32))
113 :
114 : static inline unsigned long long native_read_msr(unsigned int msr)
115 : {
116 : unsigned long long val;
117 :
118 : val = __rdmsr(msr);
119 :
120 : if (tracepoint_enabled(read_msr))
121 : do_trace_read_msr(msr, val, 0);
122 :
123 : return val;
124 : }
125 :
126 : static inline unsigned long long native_read_msr_safe(unsigned int msr,
127 : int *err)
128 : {
129 : DECLARE_ARGS(val, low, high);
130 :
131 : asm volatile("1: rdmsr ; xor %[err],%[err]\n"
132 : "2:\n\t"
133 : _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_RDMSR_SAFE, %[err])
134 : : [err] "=r" (*err), EAX_EDX_RET(val, low, high)
135 : : "c" (msr));
136 : if (tracepoint_enabled(read_msr))
137 : do_trace_read_msr(msr, EAX_EDX_VAL(val, low, high), *err);
138 : return EAX_EDX_VAL(val, low, high);
139 : }
140 :
141 : /* Can be uninlined because referenced by paravirt */
142 : static inline void notrace
143 : native_write_msr(unsigned int msr, u32 low, u32 high)
144 : {
145 : __wrmsr(msr, low, high);
146 :
147 : if (tracepoint_enabled(write_msr))
148 : do_trace_write_msr(msr, ((u64)high << 32 | low), 0);
149 : }
150 :
151 : /* Can be uninlined because referenced by paravirt */
152 : static inline int notrace
153 : native_write_msr_safe(unsigned int msr, u32 low, u32 high)
154 : {
155 : int err;
156 :
157 : asm volatile("1: wrmsr ; xor %[err],%[err]\n"
158 : "2:\n\t"
159 : _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_WRMSR_SAFE, %[err])
160 : : [err] "=a" (err)
161 : : "c" (msr), "0" (low), "d" (high)
162 : : "memory");
163 : if (tracepoint_enabled(write_msr))
164 : do_trace_write_msr(msr, ((u64)high << 32 | low), err);
165 : return err;
166 : }
167 :
168 : extern int rdmsr_safe_regs(u32 regs[8]);
169 : extern int wrmsr_safe_regs(u32 regs[8]);
170 :
171 : /**
172 : * rdtsc() - returns the current TSC without ordering constraints
173 : *
174 : * rdtsc() returns the result of RDTSC as a 64-bit integer. The
175 : * only ordering constraint it supplies is the ordering implied by
176 : * "asm volatile": it will put the RDTSC in the place you expect. The
177 : * CPU can and will speculatively execute that RDTSC, though, so the
178 : * results can be non-monotonic if compared on different CPUs.
179 : */
180 : static __always_inline unsigned long long rdtsc(void)
181 : {
182 338942 : DECLARE_ARGS(val, low, high);
183 :
184 338942 : asm volatile("rdtsc" : EAX_EDX_RET(val, low, high));
185 :
186 338942 : return EAX_EDX_VAL(val, low, high);
187 : }
188 :
189 : /**
190 : * rdtsc_ordered() - read the current TSC in program order
191 : *
192 : * rdtsc_ordered() returns the result of RDTSC as a 64-bit integer.
193 : * It is ordered like a load to a global in-memory counter. It should
194 : * be impossible to observe non-monotonic rdtsc_unordered() behavior
195 : * across multiple CPUs as long as the TSC is synced.
196 : */
197 : static __always_inline unsigned long long rdtsc_ordered(void)
198 : {
199 : DECLARE_ARGS(val, low, high);
200 :
201 : /*
202 : * The RDTSC instruction is not ordered relative to memory
203 : * access. The Intel SDM and the AMD APM are both vague on this
204 : * point, but empirically an RDTSC instruction can be
205 : * speculatively executed before prior loads. An RDTSC
206 : * immediately after an appropriate barrier appears to be
207 : * ordered as a normal load, that is, it provides the same
208 : * ordering guarantees as reading from a global memory location
209 : * that some other imaginary CPU is updating continuously with a
210 : * time stamp.
211 : *
212 : * Thus, use the preferred barrier on the respective CPU, aiming for
213 : * RDTSCP as the default.
214 : */
215 : asm volatile(ALTERNATIVE_2("rdtsc",
216 : "lfence; rdtsc", X86_FEATURE_LFENCE_RDTSC,
217 : "rdtscp", X86_FEATURE_RDTSCP)
218 : : EAX_EDX_RET(val, low, high)
219 : /* RDTSCP clobbers ECX with MSR_TSC_AUX. */
220 : :: "ecx");
221 :
222 : return EAX_EDX_VAL(val, low, high);
223 : }
224 :
225 : static inline unsigned long long native_read_pmc(int counter)
226 : {
227 : DECLARE_ARGS(val, low, high);
228 :
229 : asm volatile("rdpmc" : EAX_EDX_RET(val, low, high) : "c" (counter));
230 : if (tracepoint_enabled(rdpmc))
231 : do_trace_rdpmc(counter, EAX_EDX_VAL(val, low, high), 0);
232 : return EAX_EDX_VAL(val, low, high);
233 : }
234 :
235 : #ifdef CONFIG_PARAVIRT_XXL
236 : #include <asm/paravirt.h>
237 : #else
238 : #include <linux/errno.h>
239 : /*
240 : * Access to machine-specific registers (available on 586 and better only)
241 : * Note: the rd* operations modify the parameters directly (without using
242 : * pointer indirection), this allows gcc to optimize better
243 : */
244 :
245 : #define rdmsr(msr, low, high) \
246 : do { \
247 : u64 __val = native_read_msr((msr)); \
248 : (void)((low) = (u32)__val); \
249 : (void)((high) = (u32)(__val >> 32)); \
250 : } while (0)
251 :
252 : static inline void wrmsr(unsigned int msr, u32 low, u32 high)
253 : {
254 : native_write_msr(msr, low, high);
255 : }
256 :
257 : #define rdmsrl(msr, val) \
258 : ((val) = native_read_msr((msr)))
259 :
260 : static inline void wrmsrl(unsigned int msr, u64 val)
261 : {
262 : native_write_msr(msr, (u32)(val & 0xffffffffULL), (u32)(val >> 32));
263 : }
264 :
265 : /* wrmsr with exception handling */
266 : static inline int wrmsr_safe(unsigned int msr, u32 low, u32 high)
267 : {
268 : return native_write_msr_safe(msr, low, high);
269 : }
270 :
271 : /* rdmsr with exception handling */
272 : #define rdmsr_safe(msr, low, high) \
273 : ({ \
274 : int __err; \
275 : u64 __val = native_read_msr_safe((msr), &__err); \
276 : (*low) = (u32)__val; \
277 : (*high) = (u32)(__val >> 32); \
278 : __err; \
279 : })
280 :
281 : static inline int rdmsrl_safe(unsigned int msr, unsigned long long *p)
282 : {
283 : int err;
284 :
285 : *p = native_read_msr_safe(msr, &err);
286 : return err;
287 : }
288 :
289 : #define rdpmc(counter, low, high) \
290 : do { \
291 : u64 _l = native_read_pmc((counter)); \
292 : (low) = (u32)_l; \
293 : (high) = (u32)(_l >> 32); \
294 : } while (0)
295 :
296 : #define rdpmcl(counter, val) ((val) = native_read_pmc(counter))
297 :
298 : #endif /* !CONFIG_PARAVIRT_XXL */
299 :
300 : /*
301 : * 64-bit version of wrmsr_safe():
302 : */
303 : static inline int wrmsrl_safe(u32 msr, u64 val)
304 : {
305 : return wrmsr_safe(msr, (u32)val, (u32)(val >> 32));
306 : }
307 :
308 : struct msr *msrs_alloc(void);
309 : void msrs_free(struct msr *msrs);
310 : int msr_set_bit(u32 msr, u8 bit);
311 : int msr_clear_bit(u32 msr, u8 bit);
312 :
313 : #ifdef CONFIG_SMP
314 : int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
315 : int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
316 : int rdmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
317 : int wrmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 q);
318 : void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs);
319 : void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs);
320 : int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
321 : int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
322 : int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
323 : int wrmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q);
324 : int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]);
325 : int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]);
326 : #else /* CONFIG_SMP */
327 : static inline int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
328 : {
329 : rdmsr(msr_no, *l, *h);
330 : return 0;
331 : }
332 : static inline int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
333 : {
334 : wrmsr(msr_no, l, h);
335 : return 0;
336 : }
337 : static inline int rdmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
338 : {
339 : rdmsrl(msr_no, *q);
340 : return 0;
341 : }
342 : static inline int wrmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
343 : {
344 : wrmsrl(msr_no, q);
345 : return 0;
346 : }
347 : static inline void rdmsr_on_cpus(const struct cpumask *m, u32 msr_no,
348 : struct msr *msrs)
349 : {
350 : rdmsr_on_cpu(0, msr_no, &(msrs[0].l), &(msrs[0].h));
351 : }
352 : static inline void wrmsr_on_cpus(const struct cpumask *m, u32 msr_no,
353 : struct msr *msrs)
354 : {
355 : wrmsr_on_cpu(0, msr_no, msrs[0].l, msrs[0].h);
356 : }
357 : static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no,
358 : u32 *l, u32 *h)
359 : {
360 : return rdmsr_safe(msr_no, l, h);
361 : }
362 : static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
363 : {
364 : return wrmsr_safe(msr_no, l, h);
365 : }
366 : static inline int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
367 : {
368 : return rdmsrl_safe(msr_no, q);
369 : }
370 : static inline int wrmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
371 : {
372 : return wrmsrl_safe(msr_no, q);
373 : }
374 : static inline int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
375 : {
376 : return rdmsr_safe_regs(regs);
377 : }
378 : static inline int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
379 : {
380 : return wrmsr_safe_regs(regs);
381 : }
382 : #endif /* CONFIG_SMP */
383 : #endif /* __ASSEMBLY__ */
384 : #endif /* _ASM_X86_MSR_H */
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