Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751382AbaFMEOH (ORCPT ); Fri, 13 Jun 2014 00:14:07 -0400 Received: from h1446028.stratoserver.net ([85.214.92.142]:37694 "EHLO mail.ahsoftware.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750914AbaFMEOF (ORCPT ); Fri, 13 Jun 2014 00:14:05 -0400 From: Alexander Holler To: John Whitmore Cc: John Stultz , Alessandro Zummo , linux-kernel@vger.kernel.org, Alexander Holler Subject: [PATCH 1/3] RFC: timekeeping: introduce flag systime_was_set Date: Fri, 13 Jun 2014 06:13:24 +0200 Message-Id: <1402632806-6369-1-git-send-email-holler@ahsoftware.de> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <20140612151505.03defe29@linux.lan.towertech.it> References: <20140612151505.03defe29@linux.lan.towertech.it> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In order to let an RTC set the time at boot without the problem that a second RTC overwrites it, the flag systime_was_set is introduced. systime_was_set will be true, if a persistent clock sets the time at boot, or if do_settimeofday() is called (e.g. by the RTC subsystem or userspace). Signed-off-by: Alexander Holler --- I've based these patches on 3.15, an older version can be found at LKML, Besides discussing possible *real* bugs, I don't care what any person (including maintainers) will request. I'm fine with these patches (I'm using them since a year) and I don't play remote keyboard or patch ping-pong. If someone want changes I suggest he gets responsible for them himself and just puts a patch on top of my patches. And in any case, feel free to completely ignore these patches. (This note will destroy itself when using git am.) include/linux/time.h | 6 ++++++ kernel/time/timekeeping.c | 10 +++++++++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/time.h b/include/linux/time.h index d5d229b..888280f 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -129,6 +129,12 @@ extern int update_persistent_clock(struct timespec now); void timekeeping_init(void); extern int timekeeping_suspended; +/* + * Will be true if the system time was set at least once by + * a persistent clock, RTC or userspace. + */ +extern bool systime_was_set; + unsigned long get_seconds(void); struct timespec current_kernel_time(void); struct timespec __current_kernel_time(void); /* does not take xtime_lock */ diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index f7df8ea..6be8b72 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -43,6 +43,9 @@ int __read_mostly timekeeping_suspended; /* Flag for if there is a persistent clock on this platform */ bool __read_mostly persistent_clock_exist = false; +/* Flag for if the system time was set at least once */ +bool __read_mostly systime_was_set; + static inline void tk_normalize_xtime(struct timekeeper *tk) { while (tk->xtime_nsec >= ((u64)NSEC_PER_SEC << tk->shift)) { @@ -505,6 +508,9 @@ int do_settimeofday(const struct timespec *tv) raw_spin_lock_irqsave(&timekeeper_lock, flags); write_seqcount_begin(&timekeeper_seq); + systime_was_set = true; + + timekeeping_forward_now(tk); xt = tk_xtime(tk); @@ -799,8 +805,10 @@ void __init timekeeping_init(void) " Check your CMOS/BIOS settings.\n"); now.tv_sec = 0; now.tv_nsec = 0; - } else if (now.tv_sec || now.tv_nsec) + } else if (now.tv_sec || now.tv_nsec) { persistent_clock_exist = true; + systime_was_set = true; + } read_boot_clock(&boot); if (!timespec_valid_strict(&boot)) { -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/