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 23 static inline cycles_t get_cycles(void) 24 { 25 #ifndef CONFIG_X86_TSC 26 if (!boot_cpu_has(X86_FEATURE_TSC)) 27 return 0; 28 #endif 29 30 return rdtsc(); 31 } 32 33 extern struct system_counterval_t convert_art_to_tsc(u64 art); 34 extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns); 35 36 extern void tsc_early_delay_calibrate(void); 37 extern void tsc_init(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(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 63 static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; } 64 static inline void tsc_verify_tsc_adjust(bool resume) { } 65 static inline void check_tsc_sync_source(int cpu) { } 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