Hi!
> [ Upstream commit c163e40af9b2331b2c629fd4ec8b703ed4d4ae39 ]
>
> clocksource_delta() has two variants. One with a check for negative motion,
> which is only selected by x86. This is a historic leftover as this function
> was previously used in the time getter hot paths.
>
> Since 135225a363ae timekeeping_cycles_to_ns() has unconditional protection
> against this as a by-product of the protection against 64bit math
> overflow.
> timekeeping_advance(). The extra conditional there is not hurting anyone.
We don't have 135225a363ae in 5.10. So we probably should not have
this?
Best regards,
Pavel
> +++ b/arch/x86/Kconfig
> @@ -107,7 +107,6 @@ config X86
> select ARCH_WANTS_THP_SWAP if X86_64
> select BUILDTIME_TABLE_SORT
> select CLKEVT_I8253
> - select CLOCKSOURCE_VALIDATE_LAST_CYCLE
> select CLOCKSOURCE_WATCHDOG
> select DCACHE_WORD_ACCESS
> select EDAC_ATOMIC_SCRUB
> diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
> index a09b1d61df6a5..5cbedc0a06efc 100644
> --- a/kernel/time/Kconfig
> +++ b/kernel/time/Kconfig
> @@ -17,11 +17,6 @@ config ARCH_CLOCKSOURCE_DATA
> config ARCH_CLOCKSOURCE_INIT
> bool
>
> -# Clocksources require validation of the clocksource against the last
> -# cycle update - x86/TSC misfeature
> -config CLOCKSOURCE_VALIDATE_LAST_CYCLE
> - bool
> -
> # Timekeeping vsyscall support
> config GENERIC_TIME_VSYSCALL
> bool
> diff --git a/kernel/time/timekeeping_internal.h b/kernel/time/timekeeping_internal.h
> index 4ca2787d1642e..1d4854d5c386e 100644
> --- a/kernel/time/timekeeping_internal.h
> +++ b/kernel/time/timekeeping_internal.h
> @@ -15,7 +15,6 @@ extern void tk_debug_account_sleep_time(const struct timespec64 *t);
> #define tk_debug_account_sleep_time(x)
> #endif
>
> -#ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE
> static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
> {
> u64 ret = (now - last) & mask;
> @@ -26,12 +25,6 @@ static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
> */
> return ret & ~(mask >> 1) ? 0 : ret;
> }
> -#else
> -static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
> -{
> - return (now - last) & mask;
> -}
> -#endif
>
> /* Semi public for serialization of non timekeeper VDSO updates. */
> extern raw_spinlock_t timekeeper_lock;
--
DENX Software Engineering GmbH, Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Attachment:
signature.asc
Description: PGP signature
