First steps towards properly serializing access to the TOD clock.
- Add a mutex around the TODR, and provide lock/unlock/lock-owned functions to manipulate it. - Rename inittodr() to todr_set_systime() and resettodr() to todr_save_systime() to better reflect what they do. These functions are intended to be called with the TODR lock held, which will allow for a pattern like: -> todr_lock() -> todr_save_systime() -> [do machine-dependent stuff to sleep/suspend] -> [magically awaken] -> todr_set_systime(...) -> todr_unlock() - Provide historically-named wrappers inittodr() and resettodr() that do the dance of acquiring / releasing the lock around the actual substance. NOTE: resettodr()'s use of the TODR lock is currently disabled (and todr_save_systime() does not assert it's held) until such time as issues around shutdown / reboot under duress can be addressed.
This commit is contained in:
thorpej
parent
d21e55a432
commit
a1e56ffa5f
@ -1,7 +1,7 @@
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/* $NetBSD: clock_subr.h,v 1.28 2020/01/01 19:24:03 thorpej Exp $ */
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/* $NetBSD: clock_subr.h,v 1.29 2020/01/01 21:09:11 thorpej Exp $ */
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/*-
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* Copyright (c) 1996 The NetBSD Foundation, Inc.
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* Copyright (c) 1996, 2020 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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@ -93,10 +93,13 @@ struct todr_chip_handle {
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};
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typedef struct todr_chip_handle *todr_chip_handle_t;
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/*
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* Machine-dependent function that machine-independent RTC drivers can
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* use to register their todr_chip_handle_t with inittodr()/resettodr().
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*/
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void todr_init(void);
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void todr_attach(todr_chip_handle_t);
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void todr_lock(void);
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void todr_unlock(void);
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bool todr_lock_owned(void);
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void todr_set_systime(time_t base);
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void todr_save_systime(void);
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#endif /* _DEV_CLOCK_SUBR_H_ */
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@ -1,7 +1,7 @@
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/* $NetBSD: init_main.c,v 1.514 2019/12/31 13:07:13 ad Exp $ */
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/* $NetBSD: init_main.c,v 1.515 2020/01/01 21:09:11 thorpej Exp $ */
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/*-
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* Copyright (c) 2008, 2009, 2019 The NetBSD Foundation, Inc.
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* Copyright (c) 2008, 2009, 2019, The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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@ -97,7 +97,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.514 2019/12/31 13:07:13 ad Exp $");
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__KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.515 2020/01/01 21:09:11 thorpej Exp $");
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#include "opt_ddb.h"
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#include "opt_inet.h"
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@ -204,6 +204,8 @@ extern void *_binary_splash_image_end;
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#include <sys/pax.h>
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#include <dev/clock_subr.h>
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#include <secmodel/secmodel.h>
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#include <ufs/ufs/quota.h>
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@ -298,6 +300,7 @@ main(void)
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kernel_lock_init();
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once_init();
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todr_init();
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mi_cpu_init();
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kernconfig_lock_init();
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@ -1,4 +1,33 @@
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/* $NetBSD: kern_todr.c,v 1.43 2020/01/01 19:24:03 thorpej Exp $ */
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/* $NetBSD: kern_todr.c,v 1.44 2020/01/01 21:09:11 thorpej Exp $ */
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/*-
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* Copyright (c) 2020 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1988 University of Utah.
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@ -41,7 +70,7 @@
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#include "opt_todr.h"
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_todr.c,v 1.43 2020/01/01 19:24:03 thorpej Exp $");
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__KERNEL_RCSID(0, "$NetBSD: kern_todr.c,v 1.44 2020/01/01 21:09:11 thorpej Exp $");
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#include <sys/param.h>
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#include <sys/kernel.h>
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@ -50,35 +79,98 @@ __KERNEL_RCSID(0, "$NetBSD: kern_todr.c,v 1.43 2020/01/01 19:24:03 thorpej Exp $
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#include <sys/timetc.h>
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#include <sys/intr.h>
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#include <sys/rndsource.h>
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#include <sys/mutex.h>
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#include <dev/clock_subr.h> /* hmm.. this should probably move to sys */
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static int todr_gettime(todr_chip_handle_t, struct timeval *);
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static int todr_settime(todr_chip_handle_t, struct timeval *);
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static todr_chip_handle_t todr_handle = NULL;
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static kmutex_t todr_mutex;
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static todr_chip_handle_t todr_handle;
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static bool todr_initialized;
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/*
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* Attach the clock device to todr_handle.
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* todr_init:
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* Initialize TOD clock data.
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*/
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void
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todr_init(void)
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{
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mutex_init(&todr_mutex, MUTEX_DEFAULT, IPL_NONE);
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todr_initialized = true;
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}
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/*
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* todr_lock:
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* Acquire the TODR lock.
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*/
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void
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todr_lock(void)
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{
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mutex_enter(&todr_mutex);
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}
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/*
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* todr_unlock:
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* Release the TODR lock.
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*/
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void
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todr_unlock(void)
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{
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mutex_exit(&todr_mutex);
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}
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/*
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* todr_lock_owned:
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* Return true if the current thread owns the TODR lock.
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* This is to be used by diagnostic assertions only.
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*/
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bool
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todr_lock_owned(void)
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{
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return mutex_owned(&todr_mutex) ? true : false;
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}
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/*
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* todr_attach:
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* Attach the clock device to todr_handle.
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*/
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void
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todr_attach(todr_chip_handle_t todr)
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{
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/*
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* todr_init() is called very early in main(), but this is
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* here to catch a case where todr_attach() is called before
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* main().
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*/
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KASSERT(todr_initialized);
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todr_lock();
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if (todr_handle) {
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todr_unlock();
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printf("todr_attach: TOD already configured\n");
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return;
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}
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todr_handle = todr;
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todr_unlock();
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}
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static bool timeset = false;
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/*
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* Set up the system's time, given a `reasonable' time value.
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* todr_set_systime:
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* Set up the system's time. The "base" argument is a best-guess
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* close-enough value to use if the TOD clock is unavailable or
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* contains garbage. Must be called with the TODR lock held.
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*/
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void
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inittodr(time_t base)
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todr_set_systime(time_t base)
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{
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bool badbase = false;
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bool waszero = (base == 0);
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@ -87,6 +179,8 @@ inittodr(time_t base)
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struct timespec ts;
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struct timeval tv;
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KASSERT(todr_lock_owned());
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rnd_add_data(NULL, &base, sizeof(base), 0);
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if (base < 5 * SECS_PER_COMMON_YEAR) {
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@ -180,17 +274,19 @@ inittodr(time_t base)
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}
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/*
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* Reset the TODR based on the time value; used when the TODR
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* has a preposterous value and also when the time is reset
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* by the stime system call. Also called when the TODR goes past
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* TODRZERO + 100*(SECS_PER_COMMON_YEAR+2*SECS_PER_DAY)
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* (e.g. on Jan 2 just after midnight) to wrap the TODR around.
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* todr_save_systime:
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* Save the current system time back to the TOD clock.
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* Must be called with the TODR lock held.
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*/
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void
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resettodr(void)
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todr_save_systime(void)
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{
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struct timeval tv;
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#if notyet
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KASSERT(todr_lock_owned());
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#endif
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/*
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* We might have been called by boot() due to a crash early
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* on. Don't reset the clock chip if we don't know what time
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@ -209,6 +305,47 @@ resettodr(void)
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printf("Cannot set TOD clock time\n");
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}
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/*
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* inittodr:
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* Legacy wrapper around todr_set_systime().
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*/
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void
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inittodr(time_t base)
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{
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todr_lock();
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todr_set_systime(base);
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todr_unlock();
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}
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/*
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* resettodr:
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* Legacy wrapper around todr_save_systime().
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*/
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void
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resettodr(void)
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{
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#if notyet
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/*
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* If we're shutting down, we don't want to get stuck in case
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* someone was already fiddling with the TOD clock.
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*/
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if (shutting_down) {
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if (mutex_tryenter(&todr_mutex) == 0) {
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printf("WARNING: Cannot set TOD clock time (busy)\n");
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return;
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}
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} else {
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todr_lock();
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}
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#endif
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todr_save_systime();
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#if notyet
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todr_unlock();
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#endif
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}
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#ifdef TODR_DEBUG
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static void
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todr_debug(const char *prefix, int rv, struct clock_ymdhms *dt,
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Block a user