From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF40EC3A5A1 for ; Sun, 25 Aug 2019 09:45:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD7B820674 for ; Sun, 25 Aug 2019 09:45:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727183AbfHYJpQ (ORCPT ); Sun, 25 Aug 2019 05:45:16 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:37981 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726612AbfHYJpP (ORCPT ); Sun, 25 Aug 2019 05:45:15 -0400 Received: from localhost ([127.0.0.1] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1i1p5F-0004tL-Hk; Sun, 25 Aug 2019 11:45:13 +0200 Date: Sun, 25 Aug 2019 09:43:00 -0000 From: Thomas Gleixner To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, x86@kernel.org Subject: [GIT pull] timers/urgent for 5.3-rc5 References: <156672618029.19810.8479315461492191933.tglx@nanos.tec.linutronix.de> Message-ID: <156672618029.19810.11392026209249158095.tglx@nanos.tec.linutronix.de> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus, please pull the latest timers-urgent-for-linus git tree from: git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-for-linus up to: b99328a60a48: timekeeping/vsyscall: Prevent math overflow in BOOTTIME update A single fix for a regression caused by the generic VDSO implementation where a math overflow causes CLOCK_BOOTTIME to become a random number generator. Thanks, tglx ------------------> Thomas Gleixner (1): timekeeping/vsyscall: Prevent math overflow in BOOTTIME update include/linux/timekeeper_internal.h | 5 +++++ kernel/time/timekeeping.c | 5 +++++ kernel/time/vsyscall.c | 22 +++++++++++++--------- 3 files changed, 23 insertions(+), 9 deletions(-) diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h index 7acb953298a7..84ff2844df2a 100644 --- a/include/linux/timekeeper_internal.h +++ b/include/linux/timekeeper_internal.h @@ -57,6 +57,7 @@ struct tk_read_base { * @cs_was_changed_seq: The sequence number of clocksource change events * @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second * @raw_sec: CLOCK_MONOTONIC_RAW time in seconds + * @monotonic_to_boot: CLOCK_MONOTONIC to CLOCK_BOOTTIME offset * @cycle_interval: Number of clock cycles in one NTP interval * @xtime_interval: Number of clock shifted nano seconds in one NTP * interval. @@ -84,6 +85,9 @@ struct tk_read_base { * * wall_to_monotonic is no longer the boot time, getboottime must be * used instead. + * + * @monotonic_to_boottime is a timespec64 representation of @offs_boot to + * accelerate the VDSO update for CLOCK_BOOTTIME. */ struct timekeeper { struct tk_read_base tkr_mono; @@ -99,6 +103,7 @@ struct timekeeper { u8 cs_was_changed_seq; ktime_t next_leap_ktime; u64 raw_sec; + struct timespec64 monotonic_to_boot; /* The following members are for timekeeping internal use */ u64 cycle_interval; diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index d911c8470149..ca69290bee2a 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -146,6 +146,11 @@ static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm) static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta) { tk->offs_boot = ktime_add(tk->offs_boot, delta); + /* + * Timespec representation for VDSO update to avoid 64bit division + * on every update. + */ + tk->monotonic_to_boot = ktime_to_timespec64(tk->offs_boot); } /* diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c index 8cf3596a4ce6..4bc37ac3bb05 100644 --- a/kernel/time/vsyscall.c +++ b/kernel/time/vsyscall.c @@ -17,7 +17,7 @@ static inline void update_vdso_data(struct vdso_data *vdata, struct timekeeper *tk) { struct vdso_timestamp *vdso_ts; - u64 nsec; + u64 nsec, sec; vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last; vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask; @@ -45,23 +45,27 @@ static inline void update_vdso_data(struct vdso_data *vdata, } vdso_ts->nsec = nsec; - /* CLOCK_MONOTONIC_RAW */ - vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW]; - vdso_ts->sec = tk->raw_sec; - vdso_ts->nsec = tk->tkr_raw.xtime_nsec; + /* Copy MONOTONIC time for BOOTTIME */ + sec = vdso_ts->sec; + /* Add the boot offset */ + sec += tk->monotonic_to_boot.tv_sec; + nsec += (u64)tk->monotonic_to_boot.tv_nsec << tk->tkr_mono.shift; /* CLOCK_BOOTTIME */ vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME]; - vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; - nsec = tk->tkr_mono.xtime_nsec; - nsec += ((u64)(tk->wall_to_monotonic.tv_nsec + - ktime_to_ns(tk->offs_boot)) << tk->tkr_mono.shift); + vdso_ts->sec = sec; + while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift); vdso_ts->sec++; } vdso_ts->nsec = nsec; + /* CLOCK_MONOTONIC_RAW */ + vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW]; + vdso_ts->sec = tk->raw_sec; + vdso_ts->nsec = tk->tkr_raw.xtime_nsec; + /* CLOCK_TAI */ vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI]; vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset;