From patchwork Mon Oct 27 05:46:38 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "pang.xunlei" X-Patchwork-Id: 403388 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from mail-yh0-x237.google.com (mail-yh0-x237.google.com [IPv6:2607:f8b0:4002:c01::237]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 8C249140081 for ; Mon, 27 Oct 2014 16:47:39 +1100 (AEDT) Received: by mail-yh0-f55.google.com with SMTP id b6sf523119yha.0 for ; Sun, 26 Oct 2014 22:47:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlegroups.com; s=20120806; h=mime-version:from:to:cc:subject:date:message-id:in-reply-to :references:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:list-post:list-help :list-archive:sender:list-subscribe:list-unsubscribe:content-type; bh=8HHf2ZJ1oGAkZQ3p09aYUsBKi2iXaa30106NdyHv2hg=; b=H89dDxyMGN76bIL/1zVsKiXOQGw3oeDKCYhg1Co/MKKYuI5aJDQuXzucipgF62X6o2 WxzYwuq6+kLxFCy5UAc6hffgdrozTVnSHgcqYH2FWFbrnhZkmfYjyugg8ck4Bb6s3v71 GGFTLES8hx0ZSQM9WIsy0DBqSOaQaDwmVCF5sZh7oauipM39J1sgQx2Iu7VQciXSh7gc HYsg+v1fUxwp0QnAwhpRy5U7ePX5R6Lv+ZRXLvI+2b1WguMxOGDeedP7vjiQLGOsgEue NxcBFDBm7R6+mvGTdq2fbq5/5i9jngRnY6QPXKy30ioWXxZNrx6w1HwFYxWoGTZDnYW1 9PCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :in-reply-to:references:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:sender:list-subscribe :list-unsubscribe:content-type; bh=8HHf2ZJ1oGAkZQ3p09aYUsBKi2iXaa30106NdyHv2hg=; b=JalceGIThb8NGPl5TU6vBsQKn6JAsKODdQezM6SqDeDZnzQnyiQTwQ4nz24Jxw6rKA v2ZbFB3U68tFGjQqypMDhLIsPqBOqnt7h6wenuDhPR1vTvx5vmzForQZixAkGpc+eTau WUanLzOrDRjwlGEZLuDX426erGjjHC72v6F6i78iXnic/z4tmzTW7oO2wynMgMIJPGdw vCN4EgqAQ4cmgL5Rwm3/2d/OGaw7rqbgnP6ECdksXGfYieWN8hPF94oTJxDmVYmJI0gX bGouxRANZ0To4O5P0weAeaR42+Z8hjyHYXhtTCQDernKjhKknKyUBKPUGq1brkNLQVxM txYw== X-Received: by 10.182.110.232 with SMTP id id8mr61360obb.6.1414388857204; Sun, 26 Oct 2014 22:47:37 -0700 (PDT) MIME-Version: 1.0 X-BeenThere: rtc-linux@googlegroups.com Received: by 10.182.73.229 with SMTP id o5ls904120obv.90.gmail; Sun, 26 Oct 2014 22:47:36 -0700 (PDT) X-Received: by 10.182.168.114 with SMTP id zv18mr19321968obb.23.1414388856809; Sun, 26 Oct 2014 22:47:36 -0700 (PDT) Received: from mail-pa0-f42.google.com (mail-pa0-f42.google.com. [209.85.220.42]) by gmr-mx.google.com with ESMTPS id yr4si1251886pab.1.2014.10.26.22.47.36 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 26 Oct 2014 22:47:36 -0700 (PDT) Received-SPF: pass (google.com: domain of pang.xunlei@linaro.org designates 209.85.220.42 as permitted sender) client-ip=209.85.220.42; Received: by mail-pa0-f42.google.com with SMTP id bj1so1203247pad.1 for ; Sun, 26 Oct 2014 22:47:36 -0700 (PDT) X-Gm-Message-State: ALoCoQkmBDYSPp9O7H6VolRoMXgtPBahy2gHNjit3qfMkt2vcfwfboCyVAoZhH22mcB8iFGynSu0 X-Received: by 10.68.167.99 with SMTP id zn3mr22028351pbb.30.1414388856672; Sun, 26 Oct 2014 22:47:36 -0700 (PDT) Received: from wangdeqiang.com ([210.21.227.66]) by mx.google.com with ESMTPSA id jq5sm9723922pbc.32.2014.10.26.22.47.32 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 26 Oct 2014 22:47:36 -0700 (PDT) From: "pang.xunlei" To: linux-kernel@vger.kernel.org, rtc-linux@googlegroups.com Cc: John Stultz , Thomas Gleixner , Alessandro Zummo , "pang.xunlei" Subject: [rtc-linux] [PATCH RFC 08/12] time: Add rtc_time_to_tm() safe version(using time64_t) Date: Mon, 27 Oct 2014 13:46:38 +0800 Message-Id: <1414388802-5866-7-git-send-email-pang.xunlei@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1414388802-5866-1-git-send-email-pang.xunlei@linaro.org> References: <1414388802-5866-1-git-send-email-pang.xunlei@linaro.org> X-Original-Sender: pang.xunlei@linaro.org X-Original-Authentication-Results: gmr-mx.google.com; spf=pass (google.com: domain of pang.xunlei@linaro.org designates 209.85.220.42 as permitted sender) smtp.mail=pang.xunlei@linaro.org Reply-To: rtc-linux@googlegroups.com Precedence: list Mailing-list: list rtc-linux@googlegroups.com; contact rtc-linux+owners@googlegroups.com List-ID: X-Google-Group-Id: 712029733259 List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , The kernel uses 32-bit signed value(time_t) for seconds since 1970-01-01:00:00:00, thus it will overflow at 2038-01-19 03:14:08 on 32-bit systems. We call this "2038 safety" issue. As part of addressing 2038 saftey for in-kernel uses, this patch adds the safe rtc_time_to_tm() using time64_t. After this patch, rtc_time_to_tm_unsafe() should be replaced by rtc_time_to_tm() one by one. Eventually, rtc_time_to_tm_unsafe() will be removed from the kernel when it has no users. Signed-off-by: pang.xunlei --- drivers/rtc/rtc-lib.c | 18 ++++++++++++++---- include/linux/rtc.h | 1 + 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c index 34bcca9..cbbc9a6 100644 --- a/drivers/rtc/rtc-lib.c +++ b/drivers/rtc/rtc-lib.c @@ -48,12 +48,12 @@ EXPORT_SYMBOL(rtc_year_days); /* * Convert seconds since 01-01-1970 00:00:00 to Gregorian date. */ -void rtc_time_to_tm_unsafe(unsigned long time, struct rtc_time *tm) +void rtc_time_to_tm(time64_t time, struct rtc_time *tm) { unsigned int month, year; int days; - days = time / 86400; + days = div_s64(time, 86400); time -= (unsigned int) days * 86400; /* day of the week, 1970-01-01 was a Thursday */ @@ -81,13 +81,23 @@ void rtc_time_to_tm_unsafe(unsigned long time, struct rtc_time *tm) tm->tm_mon = month; tm->tm_mday = days + 1; - tm->tm_hour = time / 3600; + tm->tm_hour = div_s64(time, 3600); time -= tm->tm_hour * 3600; - tm->tm_min = time / 60; + tm->tm_min = div_s64(time, 60); tm->tm_sec = time - tm->tm_min * 60; tm->tm_isdst = 0; } +EXPORT_SYMBOL(rtc_time_to_tm); + +/* TODO: [2038 safety] unsafe for legacy, and should be replaced by rtc_time_to_tm() */ +void rtc_time_to_tm_unsafe(unsigned long time, struct rtc_time *tm) +{ + time64_t time64; + + time64 = (time64_t)time; + rtc_time_to_tm(time64, tm); +} EXPORT_SYMBOL(rtc_time_to_tm_unsafe); /* diff --git a/include/linux/rtc.h b/include/linux/rtc.h index d1f878c..1994399 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -21,6 +21,7 @@ extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year extern int rtc_valid_tm(struct rtc_time *tm); extern int rtc_tm_to_time(struct rtc_time *tm, time64_t *time); extern int rtc_tm_to_time_unsafe(struct rtc_time *tm, unsigned long *time); +extern void rtc_time_to_tm(time64_t time, struct rtc_time *tm); extern void rtc_time_to_tm_unsafe(unsigned long time, struct rtc_time *tm); ktime_t rtc_tm_to_ktime(struct rtc_time tm); struct rtc_time rtc_ktime_to_tm(ktime_t kt);