a36f513681
If the TSC_ADJUST MSR is available all CPUs in a package are forced to the same value. So TSCs cannot be out of sync when the first CPU in the package was in sync. That allows to skip the sync test for all CPUs except the first starting CPU in a package. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/20161119134017.809901363@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
66 lines
1.5 KiB
C
66 lines
1.5 KiB
C
/*
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* x86 TSC related functions
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*/
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#ifndef _ASM_X86_TSC_H
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#define _ASM_X86_TSC_H
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#include <asm/processor.h>
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#define NS_SCALE 10 /* 2^10, carefully chosen */
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#define US_SCALE 32 /* 2^32, arbitralrily chosen */
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/*
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* Standard way to access the cycle counter.
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*/
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typedef unsigned long long cycles_t;
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extern unsigned int cpu_khz;
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extern unsigned int tsc_khz;
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extern void disable_TSC(void);
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static inline cycles_t get_cycles(void)
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{
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#ifndef CONFIG_X86_TSC
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if (!boot_cpu_has(X86_FEATURE_TSC))
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return 0;
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#endif
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return rdtsc();
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}
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extern struct system_counterval_t convert_art_to_tsc(cycle_t art);
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extern void tsc_init(void);
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extern void mark_tsc_unstable(char *reason);
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extern int unsynchronized_tsc(void);
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extern int check_tsc_unstable(void);
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extern unsigned long native_calibrate_cpu(void);
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extern unsigned long native_calibrate_tsc(void);
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extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
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extern int tsc_clocksource_reliable;
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/*
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* Boot-time check whether the TSCs are synchronized across
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* all CPUs/cores:
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*/
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extern void check_tsc_sync_source(int cpu);
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extern void check_tsc_sync_target(void);
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#ifdef CONFIG_X86_TSC
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extern bool tsc_store_and_check_tsc_adjust(void);
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extern void tsc_verify_tsc_adjust(void);
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#else
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static inline bool tsc_store_and_check_tsc_adjust(void) { }
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static inline void tsc_verify_tsc_adjust(void) { }
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#endif
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extern int notsc_setup(char *);
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extern void tsc_save_sched_clock_state(void);
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extern void tsc_restore_sched_clock_state(void);
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unsigned long cpu_khz_from_msr(void);
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#endif /* _ASM_X86_TSC_H */
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