From patchwork Wed Apr 10 11:48:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D, Lakshmi Sowjanya" X-Patchwork-Id: 13624148 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 59CB615AD9A; Wed, 10 Apr 2024 11:48:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.14 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712749726; cv=none; b=C2gPwNQWBKhMM2/QjvjOpuCC3mtIdLNtRQ0rsqzGyb5kQTjJlESTtMF5T1dn3vxffzvZz8GSaptDewsmA0/yP9rUIRNj/tcTQAtQAhdSJyw/yDeKhTZjbarCfDHkg5c5OpNEJ9P6C25xpZu9WKrRqo5wQUnBgShf2aubVC87uqk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712749726; c=relaxed/simple; bh=GqlGR0/bnyHHT0mMIB7cQ4ab2D9OvHonlB/nEngDxSk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=mGcryLB8/FZYPAsuqugZaUr5MzwA8HWefktmRxwBSlnzQMbcoK94K/jE9bIcbUFfyvN4mZA2QQZoVEFQL+EQXa/LUCHmLu7ySsvFF4SwiZ0ObUXgDZBxvhiFJELppPCW7LuSIqiLvQc/qTMrPJHDs9NgFkZTZSEFg08NEDV0G+g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=RtiDgvFE; arc=none smtp.client-ip=198.175.65.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="RtiDgvFE" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1712749725; x=1744285725; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=GqlGR0/bnyHHT0mMIB7cQ4ab2D9OvHonlB/nEngDxSk=; b=RtiDgvFEWNCc4uLOUPNSSdujBbdbyKO6SoYcXcef/TfQkCXAL7AFYCB7 PInIcggoWAYUDRhMH/LBtPZwr8qxTbz//7TQKvhmAaKYbT3NVUxIsvOu+ 1Dkx+gmMWQWtU7HTPVEMPRBX/lMvMfmUUP9IbJRfCEoDQzBPhmwVLgPPW UPkXQmqbp3Wyr4L4LN8bqE3dyfTSRyywypzFNZzW9NEvsQycq02FEuRHP /oKhf36xWxt3ijNhJZgUCVfixyLibwukHxwnuyG2RjAf8Jywe3XoRUiLx lQAX9lYTXx1ePbCC0wVY2+Z8IfUyGILTxb0XEGCH/IB5/KZAmg3WZZq9H g==; X-CSE-ConnectionGUID: XQKVXGhvSP6w/FEZhv3smQ== X-CSE-MsgGUID: EZbm6cWxTP2Z4ora0CRA+A== X-IronPort-AV: E=McAfee;i="6600,9927,11039"; a="11944060" X-IronPort-AV: E=Sophos;i="6.07,190,1708416000"; d="scan'208";a="11944060" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Apr 2024 04:48:44 -0700 X-CSE-ConnectionGUID: OiYQycsDQEWQMHuXWQWqAg== X-CSE-MsgGUID: bop2wKIVSHyYyRVO4W3TFA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,190,1708416000"; d="scan'208";a="43769241" Received: from inlubt0316.iind.intel.com ([10.191.20.213]) by fmviesa002.fm.intel.com with ESMTP; 10 Apr 2024 04:48:36 -0700 From: lakshmi.sowjanya.d@intel.com To: tglx@linutronix.de, jstultz@google.com, giometti@enneenne.com, corbet@lwn.net, linux-kernel@vger.kernel.org Cc: x86@kernel.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org, intel-wired-lan@lists.osuosl.org, andriy.shevchenko@linux.intel.com, eddie.dong@intel.com, christopher.s.hall@intel.com, jesse.brandeburg@intel.com, davem@davemloft.net, alexandre.torgue@foss.st.com, joabreu@synopsys.com, mcoquelin.stm32@gmail.com, perex@perex.cz, linux-sound@vger.kernel.org, anthony.l.nguyen@intel.com, peter.hilber@opensynergy.com, pandith.n@intel.com, subramanian.mohan@intel.com, thejesh.reddy.t.r@intel.com, lakshmi.sowjanya.d@intel.com Subject: [PATCH v6 01/11] x86/tsc: Add base clock properties in clocksource structure Date: Wed, 10 Apr 2024 17:18:18 +0530 Message-Id: <20240410114828.25581-2-lakshmi.sowjanya.d@intel.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20240410114828.25581-1-lakshmi.sowjanya.d@intel.com> References: <20240410114828.25581-1-lakshmi.sowjanya.d@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Lakshmi Sowjanya D Add base clock hardware abstraction in clocksource structure. Add clocksource ID for x86 ART(Always Running Timer). The newly added clocksource ID and conversion parameters are used to convert time in a clocksource domain to base clock and vice versa. Convert the base clock to the system clock using convert_base_to_cs() in get_device_system_crosststamp(). Co-developed-by: Thomas Gleixner Signed-off-by: Thomas Gleixner Co-developed-by: Christopher S. Hall Signed-off-by: Christopher S. Hall Signed-off-by: Lakshmi Sowjanya D --- arch/x86/kernel/tsc.c | 42 +++++++++++++++++++-------------- include/linux/clocksource.h | 27 +++++++++++++++++++++ include/linux/clocksource_ids.h | 1 + include/linux/timekeeping.h | 2 ++ kernel/time/timekeeping.c | 37 +++++++++++++++++++++++++++-- 5 files changed, 89 insertions(+), 20 deletions(-) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 5a69a49acc96..45bf2f6d0ffa 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -50,9 +50,9 @@ int tsc_clocksource_reliable; static int __read_mostly tsc_force_recalibrate; -static u32 art_to_tsc_numerator; -static u32 art_to_tsc_denominator; -static u64 art_to_tsc_offset; +static struct clocksource_base art_base_clk = { + .id = CSID_X86_ART, +}; static bool have_art; struct cyc2ns { @@ -1074,7 +1074,7 @@ core_initcall(cpufreq_register_tsc_scaling); */ static void __init detect_art(void) { - unsigned int unused[2]; + unsigned int unused; if (boot_cpu_data.cpuid_level < ART_CPUID_LEAF) return; @@ -1089,13 +1089,14 @@ static void __init detect_art(void) tsc_async_resets) return; - cpuid(ART_CPUID_LEAF, &art_to_tsc_denominator, - &art_to_tsc_numerator, unused, unused+1); + cpuid(ART_CPUID_LEAF, &art_base_clk.denominator, + &art_base_clk.numerator, &art_base_clk.freq_khz, &unused); - if (art_to_tsc_denominator < ART_MIN_DENOMINATOR) + art_base_clk.freq_khz /= KHZ; + if (art_base_clk.denominator < ART_MIN_DENOMINATOR) return; - rdmsrl(MSR_IA32_TSC_ADJUST, art_to_tsc_offset); + rdmsrl(MSR_IA32_TSC_ADJUST, art_base_clk.offset); /* Make this sticky over multiple CPU init calls */ setup_force_cpu_cap(X86_FEATURE_ART); @@ -1303,13 +1304,13 @@ struct system_counterval_t convert_art_to_tsc(u64 art) { u64 tmp, res, rem; - rem = do_div(art, art_to_tsc_denominator); + rem = do_div(art, art_base_clk.denominator); - res = art * art_to_tsc_numerator; - tmp = rem * art_to_tsc_numerator; + res = art * art_base_clk.numerator; + tmp = rem * art_base_clk.numerator; - do_div(tmp, art_to_tsc_denominator); - res += tmp + art_to_tsc_offset; + do_div(tmp, art_base_clk.denominator); + res += tmp + art_base_clk.offset; return (struct system_counterval_t) { .cs_id = have_art ? CSID_X86_TSC : CSID_GENERIC, @@ -1356,7 +1357,6 @@ struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns) } EXPORT_SYMBOL(convert_art_ns_to_tsc); - static void tsc_refine_calibration_work(struct work_struct *work); static DECLARE_DELAYED_WORK(tsc_irqwork, tsc_refine_calibration_work); /** @@ -1458,8 +1458,10 @@ static void tsc_refine_calibration_work(struct work_struct *work) if (tsc_unstable) goto unreg; - if (boot_cpu_has(X86_FEATURE_ART)) + if (boot_cpu_has(X86_FEATURE_ART)) { have_art = true; + clocksource_tsc.base = &art_base_clk; + } clocksource_register_khz(&clocksource_tsc, tsc_khz); unreg: clocksource_unregister(&clocksource_tsc_early); @@ -1484,8 +1486,10 @@ static int __init init_tsc_clocksource(void) * the refined calibration and directly register it as a clocksource. */ if (boot_cpu_has(X86_FEATURE_TSC_KNOWN_FREQ)) { - if (boot_cpu_has(X86_FEATURE_ART)) + if (boot_cpu_has(X86_FEATURE_ART)) { have_art = true; + clocksource_tsc.base = &art_base_clk; + } clocksource_register_khz(&clocksource_tsc, tsc_khz); clocksource_unregister(&clocksource_tsc_early); @@ -1509,10 +1513,12 @@ static bool __init determine_cpu_tsc_frequencies(bool early) if (early) { cpu_khz = x86_platform.calibrate_cpu(); - if (tsc_early_khz) + if (tsc_early_khz) { tsc_khz = tsc_early_khz; - else + } else { tsc_khz = x86_platform.calibrate_tsc(); + clocksource_tsc.freq_khz = tsc_khz; + } } else { /* We should not be here with non-native cpu calibration */ WARN_ON(x86_platform.calibrate_cpu != native_calibrate_cpu); diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 0ad8b550bb4b..66a033bff17c 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -21,6 +21,7 @@ #include #include +struct clocksource_base; struct clocksource; struct module; @@ -48,6 +49,7 @@ struct module; * @archdata: Optional arch-specific data * @max_cycles: Maximum safe cycle value which won't overflow on * multiplication + * @freq_khz: Clocksource frequency in khz. * @name: Pointer to clocksource name * @list: List head for registration (internal) * @rating: Rating value for selection (higher is better) @@ -70,6 +72,8 @@ struct module; * validate the clocksource from which the snapshot was * taken. * @flags: Flags describing special properties + * @base: Hardware abstraction for clock on which a clocksource + * is based * @enable: Optional function to enable the clocksource * @disable: Optional function to disable the clocksource * @suspend: Optional suspend function for the clocksource @@ -105,12 +109,14 @@ struct clocksource { struct arch_clocksource_data archdata; #endif u64 max_cycles; + u32 freq_khz; const char *name; struct list_head list; int rating; enum clocksource_ids id; enum vdso_clock_mode vdso_clock_mode; unsigned long flags; + struct clocksource_base *base; int (*enable)(struct clocksource *cs); void (*disable)(struct clocksource *cs); @@ -306,4 +312,25 @@ static inline unsigned int clocksource_get_max_watchdog_retry(void) void clocksource_verify_percpu(struct clocksource *cs); +/** + * struct clocksource_base - hardware abstraction for clock on which a clocksource + * is based + * @id: Defaults to CSID_GENERIC. The id value is used for conversion + * functions which require that the current clocksource is based + * on a clocksource_base with a particular ID in certain snapshot + * functions to allow callers to validate the clocksource from + * which the snapshot was taken. + * @freq_khz: Nominal frequency of the base clock in kHz + * @offset: Offset between the base clock and the clocksource + * @numerator: Numerator of the clock ratio between base clock and the clocksource + * @denominator: Denominator of the clock ratio between base clock and the clocksource + */ +struct clocksource_base { + enum clocksource_ids id; + u32 freq_khz; + u64 offset; + u32 numerator; + u32 denominator; +}; + #endif /* _LINUX_CLOCKSOURCE_H */ diff --git a/include/linux/clocksource_ids.h b/include/linux/clocksource_ids.h index a4fa3436940c..2bb4d8c2f1b0 100644 --- a/include/linux/clocksource_ids.h +++ b/include/linux/clocksource_ids.h @@ -9,6 +9,7 @@ enum clocksource_ids { CSID_X86_TSC_EARLY, CSID_X86_TSC, CSID_X86_KVM_CLK, + CSID_X86_ART, CSID_MAX, }; diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index 0ea7823b7f31..b2ee182d891e 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -310,10 +310,12 @@ struct system_device_crosststamp { * timekeeping code to verify comparability of two cycle values. * The default ID, CSID_GENERIC, does not identify a specific * clocksource. + * @use_nsecs: @cycles is in nanoseconds. */ struct system_counterval_t { u64 cycles; enum clocksource_ids cs_id; + bool use_nsecs; }; /* diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index b58dffc58a8f..2542cfefbdee 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1193,6 +1193,40 @@ static bool timestamp_in_interval(u64 start, u64 end, u64 ts) return false; } +static bool convert_clock(u64 *val, u32 numerator, u32 denominator) +{ + u64 rem, res; + + if (!numerator || !denominator) + return false; + + res = div64_u64_rem(*val, denominator, &rem) * numerator; + *val = res + div_u64(rem * numerator, denominator); + return true; +} + +static bool convert_base_to_cs(struct system_counterval_t *scv) +{ + struct clocksource *cs = tk_core.timekeeper.tkr_mono.clock; + struct clocksource_base *base = cs->base; + u32 num, den; + + /* The timestamp was taken from the time keeper clock source */ + if (cs->id == scv->cs_id) + return true; + + /* Check whether cs_id matches the base clock */ + if (!base || base->id != scv->cs_id) + return false; + + num = scv->use_nsecs ? cs->freq_khz : base->numerator; + den = scv->use_nsecs ? USEC_PER_SEC : base->denominator; + + convert_clock(&scv->cycles, num, den); + scv->cycles += base->offset; + return true; +} + /** * get_device_system_crosststamp - Synchronously capture system/device timestamp * @get_time_fn: Callback to get simultaneous device time and @@ -1238,8 +1272,7 @@ int get_device_system_crosststamp(int (*get_time_fn) * system counter value is the same as for the currently * installed timekeeper clocksource */ - if (system_counterval.cs_id == CSID_GENERIC || - tk->tkr_mono.clock->id != system_counterval.cs_id) + if (!convert_base_to_cs(&system_counterval)) return -ENODEV; cycles = system_counterval.cycles;