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9d349d47f0
Spin-waiting on the control CPU until the AP reaches the TSC synchronization is just a waste especially in the case that there is no synchronization required. As the synchronization has to run with interrupts disabled the control CPU part can just be done from a SMP function call. The upcoming AP issues that call async only in the case that synchronization is required. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Helge Deller <deller@gmx.de> # parisc Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck Link: https://lore.kernel.org/r/20230512205256.148255496@linutronix.de
72 lines
1.9 KiB
C
72 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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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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#include <asm/cpufeature.h>
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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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if (!IS_ENABLED(CONFIG_X86_TSC) &&
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!cpu_feature_enabled(X86_FEATURE_TSC))
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return 0;
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return rdtsc();
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}
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#define get_cycles get_cycles
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extern struct system_counterval_t convert_art_to_tsc(u64 art);
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extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
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extern void tsc_early_init(void);
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extern void tsc_init(void);
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extern unsigned long calibrate_delay_is_known(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 void mark_tsc_async_resets(char *reason);
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extern unsigned long native_calibrate_cpu_early(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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#ifdef CONFIG_X86_TSC
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extern bool tsc_async_resets;
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#else
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# define tsc_async_resets false
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#endif
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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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#ifdef CONFIG_X86_TSC
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extern bool tsc_store_and_check_tsc_adjust(bool bootcpu);
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extern void tsc_verify_tsc_adjust(bool resume);
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extern void check_tsc_sync_target(void);
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#else
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static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; }
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static inline void tsc_verify_tsc_adjust(bool resume) { }
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static inline void check_tsc_sync_target(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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