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 __ASSEMBLER__
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#include <linux/types.h>
16#include <linux/percpu.h>
17
18struct msr_info {
19 u32 msr_no;
20 struct msr reg;
21 struct msr __percpu *msrs;
22 int err;
23};
24
25struct msr_regs_info {
26 u32 *regs;
27 int err;
28};
29
30struct saved_msr {
31 bool valid;
32 struct msr_info info;
33};
34
35struct saved_msrs {
36 unsigned int num;
37 struct saved_msr *array;
38};
39
40/*
41 * Be very careful with includes. This header is prone to include loops.
42 */
43#include <asm/atomic.h>
44#include <linux/tracepoint-defs.h>
45
46#ifdef CONFIG_TRACEPOINTS
47DECLARE_TRACEPOINT(read_msr);
48DECLARE_TRACEPOINT(write_msr);
49DECLARE_TRACEPOINT(rdpmc);
50extern void do_trace_write_msr(u32 msr, u64 val, int failed);
51extern void do_trace_read_msr(u32 msr, u64 val, int failed);
52extern void do_trace_rdpmc(u32 msr, u64 val, int failed);
53#else
54static inline void do_trace_write_msr(u32 msr, u64 val, int failed) {}
55static inline void do_trace_read_msr(u32 msr, u64 val, int failed) {}
56static inline void do_trace_rdpmc(u32 msr, u64 val, int failed) {}
57#endif
58
59/*
60 * __rdmsr() and __wrmsr() are the two primitives which are the bare minimum MSR
61 * accessors and should not have any tracing or other functionality piggybacking
62 * on them - those are *purely* for accessing MSRs and nothing more. So don't even
63 * think of extending them - you will be slapped with a stinking trout or a frozen
64 * shark will reach you, wherever you are! You've been warned.
65 */
66static __always_inline u64 __rdmsr(u32 msr)
67{
68 EAX_EDX_DECLARE_ARGS(val, low, high);
69
70 asm volatile("1: rdmsr\n"
71 "2:\n"
72 _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_RDMSR)
73 : EAX_EDX_RET(val, low, high) : "c" (msr));
74
75 return EAX_EDX_VAL(val, low, high);
76}
77
78static __always_inline void __wrmsrq(u32 msr, u64 val)
79{
80 asm volatile("1: wrmsr\n"
81 "2:\n"
82 _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_WRMSR)
83 : : "c" (msr), "a" ((u32)val), "d" ((u32)(val >> 32)) : "memory");
84}
85
86#define native_rdmsr(msr, val1, val2) \
87do { \
88 u64 __val = __rdmsr((msr)); \
89 (void)((val1) = (u32)__val); \
90 (void)((val2) = (u32)(__val >> 32)); \
91} while (0)
92
93static __always_inline u64 native_rdmsrq(u32 msr)
94{
95 return __rdmsr(msr);
96}
97
98#define native_wrmsr(msr, low, high) \
99 __wrmsrq((msr), (u64)(high) << 32 | (low))
100
101#define native_wrmsrq(msr, val) \
102 __wrmsrq((msr), (val))
103
104static inline u64 native_read_msr(u32 msr)
105{
106 u64 val;
107
108 val = __rdmsr(msr);
109
110 if (tracepoint_enabled(read_msr))
111 do_trace_read_msr(msr, val, failed: 0);
112
113 return val;
114}
115
116static inline int native_read_msr_safe(u32 msr, u64 *p)
117{
118 int err;
119 EAX_EDX_DECLARE_ARGS(val, low, high);
120
121 asm volatile("1: rdmsr ; xor %[err],%[err]\n"
122 "2:\n\t"
123 _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_RDMSR_SAFE, %[err])
124 : [err] "=r" (err), EAX_EDX_RET(val, low, high)
125 : "c" (msr));
126 if (tracepoint_enabled(read_msr))
127 do_trace_read_msr(msr, EAX_EDX_VAL(val, low, high), failed: err);
128
129 *p = EAX_EDX_VAL(val, low, high);
130
131 return err;
132}
133
134/* Can be uninlined because referenced by paravirt */
135static inline void notrace native_write_msr(u32 msr, u64 val)
136{
137 native_wrmsrq(msr, val);
138
139 if (tracepoint_enabled(write_msr))
140 do_trace_write_msr(msr, val, failed: 0);
141}
142
143/* Can be uninlined because referenced by paravirt */
144static inline int notrace native_write_msr_safe(u32 msr, u64 val)
145{
146 int err;
147
148 asm volatile("1: wrmsr ; xor %[err],%[err]\n"
149 "2:\n\t"
150 _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_WRMSR_SAFE, %[err])
151 : [err] "=a" (err)
152 : "c" (msr), "0" ((u32)val), "d" ((u32)(val >> 32))
153 : "memory");
154 if (tracepoint_enabled(write_msr))
155 do_trace_write_msr(msr, val, failed: err);
156 return err;
157}
158
159extern int rdmsr_safe_regs(u32 regs[8]);
160extern int wrmsr_safe_regs(u32 regs[8]);
161
162static inline u64 native_read_pmc(int counter)
163{
164 EAX_EDX_DECLARE_ARGS(val, low, high);
165
166 asm volatile("rdpmc" : EAX_EDX_RET(val, low, high) : "c" (counter));
167 if (tracepoint_enabled(rdpmc))
168 do_trace_rdpmc(msr: counter, EAX_EDX_VAL(val, low, high), failed: 0);
169 return EAX_EDX_VAL(val, low, high);
170}
171
172#ifdef CONFIG_PARAVIRT_XXL
173#include <asm/paravirt.h>
174#else
175#include <linux/errno.h>
176/*
177 * Access to machine-specific registers (available on 586 and better only)
178 * Note: the rd* operations modify the parameters directly (without using
179 * pointer indirection), this allows gcc to optimize better
180 */
181
182#define rdmsr(msr, low, high) \
183do { \
184 u64 __val = native_read_msr((msr)); \
185 (void)((low) = (u32)__val); \
186 (void)((high) = (u32)(__val >> 32)); \
187} while (0)
188
189static inline void wrmsr(u32 msr, u32 low, u32 high)
190{
191 native_write_msr(msr, (u64)high << 32 | low);
192}
193
194#define rdmsrq(msr, val) \
195 ((val) = native_read_msr((msr)))
196
197static inline void wrmsrq(u32 msr, u64 val)
198{
199 native_write_msr(msr, val);
200}
201
202/* wrmsr with exception handling */
203static inline int wrmsrq_safe(u32 msr, u64 val)
204{
205 return native_write_msr_safe(msr, val);
206}
207
208/* rdmsr with exception handling */
209#define rdmsr_safe(msr, low, high) \
210({ \
211 u64 __val; \
212 int __err = native_read_msr_safe((msr), &__val); \
213 (*low) = (u32)__val; \
214 (*high) = (u32)(__val >> 32); \
215 __err; \
216})
217
218static inline int rdmsrq_safe(u32 msr, u64 *p)
219{
220 return native_read_msr_safe(msr, p);
221}
222
223static __always_inline u64 rdpmc(int counter)
224{
225 return native_read_pmc(counter);
226}
227
228#endif /* !CONFIG_PARAVIRT_XXL */
229
230/* Instruction opcode for WRMSRNS supported in binutils >= 2.40 */
231#define ASM_WRMSRNS _ASM_BYTES(0x0f,0x01,0xc6)
232
233/* Non-serializing WRMSR, when available. Falls back to a serializing WRMSR. */
234static __always_inline void wrmsrns(u32 msr, u64 val)
235{
236 /*
237 * WRMSR is 2 bytes. WRMSRNS is 3 bytes. Pad WRMSR with a redundant
238 * DS prefix to avoid a trailing NOP.
239 */
240 asm volatile("1: " ALTERNATIVE("ds wrmsr", ASM_WRMSRNS, X86_FEATURE_WRMSRNS)
241 "2: " _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_WRMSR)
242 : : "c" (msr), "a" ((u32)val), "d" ((u32)(val >> 32)));
243}
244
245/*
246 * Dual u32 version of wrmsrq_safe():
247 */
248static inline int wrmsr_safe(u32 msr, u32 low, u32 high)
249{
250 return wrmsrq_safe(msr, val: (u64)high << 32 | low);
251}
252
253struct msr __percpu *msrs_alloc(void);
254void msrs_free(struct msr __percpu *msrs);
255int msr_set_bit(u32 msr, u8 bit);
256int msr_clear_bit(u32 msr, u8 bit);
257
258#ifdef CONFIG_SMP
259int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
260int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
261int rdmsrq_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
262int wrmsrq_on_cpu(unsigned int cpu, u32 msr_no, u64 q);
263void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr __percpu *msrs);
264void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr __percpu *msrs);
265int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
266int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
267int rdmsrq_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
268int wrmsrq_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q);
269int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]);
270int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]);
271#else /* CONFIG_SMP */
272static inline int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
273{
274 rdmsr(msr_no, *l, *h);
275 return 0;
276}
277static inline int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
278{
279 wrmsr(msr_no, l, h);
280 return 0;
281}
282static inline int rdmsrq_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
283{
284 rdmsrq(msr_no, *q);
285 return 0;
286}
287static inline int wrmsrq_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
288{
289 wrmsrq(msr_no, q);
290 return 0;
291}
292static inline void rdmsr_on_cpus(const struct cpumask *m, u32 msr_no,
293 struct msr __percpu *msrs)
294{
295 rdmsr_on_cpu(0, msr_no, raw_cpu_ptr(&msrs->l), raw_cpu_ptr(&msrs->h));
296}
297static inline void wrmsr_on_cpus(const struct cpumask *m, u32 msr_no,
298 struct msr __percpu *msrs)
299{
300 wrmsr_on_cpu(0, msr_no, raw_cpu_read(msrs->l), raw_cpu_read(msrs->h));
301}
302static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no,
303 u32 *l, u32 *h)
304{
305 return rdmsr_safe(msr_no, l, h);
306}
307static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
308{
309 return wrmsr_safe(msr_no, l, h);
310}
311static inline int rdmsrq_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
312{
313 return rdmsrq_safe(msr_no, q);
314}
315static inline int wrmsrq_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
316{
317 return wrmsrq_safe(msr_no, q);
318}
319static inline int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
320{
321 return rdmsr_safe_regs(regs);
322}
323static inline int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
324{
325 return wrmsr_safe_regs(regs);
326}
327#endif /* CONFIG_SMP */
328
329/* Compatibility wrappers: */
330#define rdmsrl(msr, val) rdmsrq(msr, val)
331#define wrmsrl(msr, val) wrmsrq(msr, val)
332#define rdmsrl_on_cpu(cpu, msr, q) rdmsrq_on_cpu(cpu, msr, q)
333
334#endif /* __ASSEMBLER__ */
335#endif /* _ASM_X86_MSR_H */
336

source code of linux/arch/x86/include/asm/msr.h