From nobody Mon Feb 7 15:18:29 2022 X-Original-To: freebsd-hackers@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 6F8B919A83BC for ; Mon, 7 Feb 2022 15:18:44 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4JsqXz496tz4TQ7 for ; Mon, 7 Feb 2022 15:18:43 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.16.1/8.16.1) with ESMTPS id 217FITWH004320 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 7 Feb 2022 17:18:33 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by tom.home (8.16.1/8.16.1/Submit) id 217FITLF004319; Mon, 7 Feb 2022 17:18:29 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Mon, 7 Feb 2022 17:18:29 +0200 From: Konstantin Belousov To: Sebastian Huber Cc: FreeBSD Hackers Subject: Re: ntp_init() looks like a nop Message-ID: References: List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-hackers@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.5 X-Spam-Checker-Version: SpamAssassin 3.4.5 (2021-03-20) on tom.home X-Rspamd-Queue-Id: 4JsqXz496tz4TQ7 X-Spamd-Bar: ++ Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=gmail.com (policy=none); spf=softfail (mx1.freebsd.org: 2001:470:d5e7:1::1 is neither permitted nor denied by domain of kostikbel@gmail.com) smtp.mailfrom=kostikbel@gmail.com X-Spamd-Result: default: False [2.88 / 15.00]; ARC_NA(0.00)[]; RCVD_TLS_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_FROM(0.00)[gmail.com]; NEURAL_SPAM_SHORT(0.88)[0.881]; MIME_GOOD(-0.10)[text/plain]; HAS_XAW(0.00)[]; R_SPF_SOFTFAIL(0.00)[~all:c]; NEURAL_SPAM_MEDIUM(1.00)[1.000]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; NEURAL_SPAM_LONG(1.00)[1.000]; MLMMJ_DEST(0.00)[freebsd-hackers]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US]; RCVD_COUNT_TWO(0.00)[2]; FREEMAIL_ENVFROM(0.00)[gmail.com]; DMARC_POLICY_SOFTFAIL(0.10)[gmail.com : No valid SPF, No valid DKIM,none] X-ThisMailContainsUnwantedMimeParts: N On Mon, Feb 07, 2022 at 04:04:56PM +0100, Sebastian Huber wrote: > Hello, > > I review currently the kern_ntptime.c module since I would like to use it in > RTEMS. I have a question to ntp_init(): > > /* > * ntp_init() - initialize variables and structures > * > * This routine must be called after the kernel variables hz and tick > * are set or changed and before the next tick interrupt. In this > * particular implementation, these values are assumed set elsewhere in > * the kernel. The design allows the clock frequency and tick interval > * to be changed while the system is running. So, this routine should > * probably be integrated with the code that does that. > */ > static void > ntp_init(void) > { > > /* > * The following variables are initialized only at startup. Only > * those structures not cleared by the compiler need to be > * initialized, and these only in the simulator. In the actual > * kernel, any nonzero values here will quickly evaporate. > */ > L_CLR(time_offset); > L_CLR(time_freq); > #ifdef PPS_SYNC > pps_tf[0].tv_sec = pps_tf[0].tv_nsec = 0; > pps_tf[1].tv_sec = pps_tf[1].tv_nsec = 0; > pps_tf[2].tv_sec = pps_tf[2].tv_nsec = 0; > pps_fcount = 0; > L_CLR(pps_freq); > #endif /* PPS_SYNC */ > } > > SYSINIT(ntpclocks, SI_SUB_CLOCKS, SI_ORDER_MIDDLE, ntp_init, NULL); > > The ntp_init() function sets a couple of global variables to zero. These > variables should be in the .bss section. Are they not already cleared during > the kernel loading? This is nop indeed, be it linked in kernel, or loaded as a module.