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_init(void);
  37extern void tsc_init(void);
  38extern unsigned long calibrate_delay_is_known(void);
  39extern void mark_tsc_unstable(char *reason);
  40extern int unsynchronized_tsc(void);
  41extern int check_tsc_unstable(void);
  42extern void mark_tsc_async_resets(char *reason);
  43extern unsigned long native_calibrate_cpu_early(void);
  44extern unsigned long native_calibrate_tsc(void);
  45extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
  46
  47extern int tsc_clocksource_reliable;
  48#ifdef CONFIG_X86_TSC
  49extern bool tsc_async_resets;
  50#else
  51# define tsc_async_resets       false
  52#endif
  53
  54/*
  55 * Boot-time check whether the TSCs are synchronized across
  56 * all CPUs/cores:
  57 */
  58#ifdef CONFIG_X86_TSC
  59extern bool tsc_store_and_check_tsc_adjust(bool bootcpu);
  60extern void tsc_verify_tsc_adjust(bool resume);
  61extern void check_tsc_sync_source(int cpu);
  62extern void check_tsc_sync_target(void);
  63#else
  64static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; }
  65static inline void tsc_verify_tsc_adjust(bool resume) { }
  66static inline void check_tsc_sync_source(int cpu) { }
  67static inline void check_tsc_sync_target(void) { }
  68#endif
  69
  70extern int notsc_setup(char *);
  71extern void tsc_save_sched_clock_state(void);
  72extern void tsc_restore_sched_clock_state(void);
  73
  74unsigned long cpu_khz_from_msr(void);
  75
  76#endif /* _ASM_X86_TSC_H */
  77