LXR linux/arch/x86/include/asm/tsc.h

   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 */
  16typedef unsigned long long cycles_t;
  17
  18extern unsigned int cpu_khz;
  19extern unsigned int tsc_khz;
  20
  21extern void disable_TSC(void);
  22
  23static 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
  33extern struct system_counterval_t convert_art_to_tsc(u64 art);
  34extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
  35
  36extern void tsc_early_delay_calibrate(void);
  37extern void tsc_init(void);
  38extern void mark_tsc_unstable(char *reason);
  39extern int unsynchronized_tsc(void);
  40extern int check_tsc_unstable(void);
  41extern void mark_tsc_async_resets(char *reason);
  42extern unsigned long native_calibrate_cpu(void);
  43extern unsigned long native_calibrate_tsc(void);
  44extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
  45
  46extern int tsc_clocksource_reliable;
  47#ifdef CONFIG_X86_TSC
  48extern 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
  58extern bool tsc_store_and_check_tsc_adjust(bool bootcpu);
  59extern void tsc_verify_tsc_adjust(bool resume);
  60extern void check_tsc_sync_source(int cpu);
  61extern void check_tsc_sync_target(void);
  62#else
  63static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; }
  64static inline void tsc_verify_tsc_adjust(bool resume) { }
  65static inline void check_tsc_sync_source(int cpu) { }
  66static inline void check_tsc_sync_target(void) { }
  67#endif
  68
  69extern int notsc_setup(char *);
  70extern void tsc_save_sched_clock_state(void);
  71extern void tsc_restore_sched_clock_state(void);
  72
  73unsigned long cpu_khz_from_msr(void);
  74
  75#endif /* _ASM_X86_TSC_H */
  76