From 94ecbf1e71d463080c36a6e494e067e5a30ad0f0 Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Fri, 25 Apr 2025 10:19:28 +0200 Subject: [PATCH] s390/time: Remove in-kernel time steering Remove the in-kernel time steering in favour of the new ptp s390 driver, which allows the kernel clock to be steered more precise. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Alexander Gordeev --- arch/s390/include/asm/vdso/gettimeofday.h | 8 +---- arch/s390/include/asm/vdso/time_data.h | 3 +- arch/s390/kernel/time.c | 39 ++--------------------- 3 files changed, 5 insertions(+), 45 deletions(-) diff --git a/arch/s390/include/asm/vdso/gettimeofday.h b/arch/s390/include/asm/vdso/gettimeofday.h index fb4564308e9d7..c31ac5f61c83e 100644 --- a/arch/s390/include/asm/vdso/gettimeofday.h +++ b/arch/s390/include/asm/vdso/gettimeofday.h @@ -16,13 +16,7 @@ static inline u64 __arch_get_hw_counter(s32 clock_mode, const struct vdso_time_data *vd) { - u64 adj, now; - - now = get_tod_clock(); - adj = vd->arch_data.tod_steering_end - now; - if (unlikely((s64) adj > 0)) - now += (vd->arch_data.tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15); - return now; + return get_tod_clock() - vd->arch_data.tod_delta; } static __always_inline diff --git a/arch/s390/include/asm/vdso/time_data.h b/arch/s390/include/asm/vdso/time_data.h index 8a08752422e60..25c4e0d9f596d 100644 --- a/arch/s390/include/asm/vdso/time_data.h +++ b/arch/s390/include/asm/vdso/time_data.h @@ -5,8 +5,7 @@ #include struct arch_vdso_time_data { - __s64 tod_steering_delta; - __u64 tod_steering_end; + __s64 tod_delta; }; #endif /* __S390_ASM_VDSO_TIME_DATA_H */ diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index cb7ed55e24d20..02c7bebd0b3ca 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -69,8 +69,6 @@ unsigned char ptff_function_mask[16]; static unsigned long lpar_offset; static unsigned long initial_leap_seconds; -static unsigned long tod_steering_end; -static long tod_steering_delta; /* * Get time offsets with PTFF @@ -80,9 +78,7 @@ void __init time_early_init(void) struct ptff_qto qto; struct ptff_qui qui; - /* Initialize TOD steering parameters */ - tod_steering_end = tod_clock_base.tod; - vdso_k_time_data->arch_data.tod_steering_end = tod_steering_end; + vdso_k_time_data->arch_data.tod_delta = tod_clock_base.tod; if (!test_facility(28)) return; @@ -226,21 +222,7 @@ void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time, static u64 read_tod_clock(struct clocksource *cs) { - unsigned long now, adj; - - preempt_disable(); /* protect from changes to steering parameters */ - now = get_tod_clock(); - adj = tod_steering_end - now; - if (unlikely((s64) adj > 0)) - /* - * manually steer by 1 cycle every 2^16 cycles. This - * corresponds to shifting the tod delta by 15. 1s is - * therefore steered in ~9h. The adjust will decrease - * over time, until it finally reaches 0. - */ - now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15); - preempt_enable(); - return now; + return get_tod_clock_monotonic(); } static struct clocksource clocksource_tod = { @@ -369,26 +351,11 @@ static inline int check_sync_clock(void) */ static void clock_sync_global(long delta) { - unsigned long now, adj; struct ptff_qto qto; /* Fixup the monotonic sched clock. */ tod_clock_base.eitod += delta; - /* Adjust TOD steering parameters. */ - now = get_tod_clock(); - adj = tod_steering_end - now; - if (unlikely((s64) adj >= 0)) - /* Calculate how much of the old adjustment is left. */ - tod_steering_delta = (tod_steering_delta < 0) ? - -(adj >> 15) : (adj >> 15); - tod_steering_delta += delta; - if ((abs(tod_steering_delta) >> 48) != 0) - panic("TOD clock sync offset %li is too large to drift\n", - tod_steering_delta); - tod_steering_end = now + (abs(tod_steering_delta) << 15); - vdso_k_time_data->arch_data.tod_steering_end = tod_steering_end; - vdso_k_time_data->arch_data.tod_steering_delta = tod_steering_delta; - + vdso_k_time_data->arch_data.tod_delta = tod_clock_base.tod; /* Update LPAR offset. */ if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0) lpar_offset = qto.tod_epoch_difference; -- 2.47.2