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1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * x86 TSC related functions
4  */
5 #ifndef _ASM_X86_TSC_H
6 #define _ASM_X86_TSC_H
7 
8 #include <asm/processor.h>
9 
10 #define NS_SCALE	10 /* 2^10, carefully chosen */
11 #define US_SCALE	32 /* 2^32, arbitralrily chosen */
12 
13 /*
14  * Standard way to access the cycle counter.
15  */
16 typedef unsigned long long cycles_t;
17 
18 extern unsigned int cpu_khz;
19 extern unsigned int tsc_khz;
20 
21 extern void disable_TSC(void);
22 
get_cycles(void)23 static inline cycles_t get_cycles(void)
24 {
25 	if (!IS_ENABLED(CONFIG_X86_TSC) &&
26 	    !cpu_feature_enabled(X86_FEATURE_TSC))
27 		return 0;
28 	return rdtsc();
29 }
30 #define get_cycles get_cycles
31 
32 extern struct system_counterval_t convert_art_to_tsc(u64 art);
33 extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
34 
35 extern void tsc_early_init(void);
36 extern void tsc_init(void);
37 extern unsigned long calibrate_delay_is_known(void);
38 extern void mark_tsc_unstable(char *reason);
39 extern int unsynchronized_tsc(void);
40 extern int check_tsc_unstable(void);
41 extern void mark_tsc_async_resets(char *reason);
42 extern unsigned long native_calibrate_cpu_early(void);
43 extern unsigned long native_calibrate_tsc(void);
44 extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
45 
46 extern int tsc_clocksource_reliable;
47 #ifdef CONFIG_X86_TSC
48 extern bool tsc_async_resets;
49 #else
50 # define tsc_async_resets	false
51 #endif
52 
53 /*
54  * Boot-time check whether the TSCs are synchronized across
55  * all CPUs/cores:
56  */
57 #ifdef CONFIG_X86_TSC
58 extern bool tsc_store_and_check_tsc_adjust(bool bootcpu);
59 extern void tsc_verify_tsc_adjust(bool resume);
60 extern void check_tsc_sync_source(int cpu);
61 extern void check_tsc_sync_target(void);
62 #else
tsc_store_and_check_tsc_adjust(bool bootcpu)63 static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; }
tsc_verify_tsc_adjust(bool resume)64 static inline void tsc_verify_tsc_adjust(bool resume) { }
check_tsc_sync_source(int cpu)65 static inline void check_tsc_sync_source(int cpu) { }
check_tsc_sync_target(void)66 static inline void check_tsc_sync_target(void) { }
67 #endif
68 
69 extern int notsc_setup(char *);
70 extern void tsc_save_sched_clock_state(void);
71 extern void tsc_restore_sched_clock_state(void);
72 
73 unsigned long cpu_khz_from_msr(void);
74 
75 #endif /* _ASM_X86_TSC_H */
76