From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 220C61624D5; Fri, 11 Apr 2025 13:38:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744378725; cv=none; b=hLzzCIzUaDaXHzkoDjgEECTtsTk0Lh7yPcke5LJECssTSKthzo54b4rCkr/WnJnRiye2OXCsa8JlHUchMEiwmBkUoZrajTSi/qNM1lBTXSwumpRm3pQ3urFY9M3EFiXDmk3wCvDrlvE7eSw12xNBt+ECW+ov11eP1t88ue17Gw8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744378725; c=relaxed/simple; bh=9nOXjdvRPnZ2BF4Sz2SL+rND/MjoCbT+d+bZEAd8Qrk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KnfOr4sYCVBtIt5YgWeibvMr4eU6WUWGhDr5XJe9HJEUwAjfGBKNAp8o0PvNTnBQ+kTcYoV1nas9jBRp4p9mlRsTTejIiTSnvLrIbNYD1d5Icq7sjgJwvEpzHt/VxSYviJaasOrpHYJXhcKuuKaoyfktDYsfVg/K5PpV6is5XOo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=iWU8Dx/J; arc=none smtp.client-ip=217.70.183.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="iWU8Dx/J" Received: by mail.gandi.net (Postfix) with ESMTPSA id A709143837; Fri, 11 Apr 2025 13:38:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1744378721; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Se307jMf8bJRrVTshEHtUk2COFPI+eANTJd1fN8fBls=; b=iWU8Dx/JYqm/sFQgZoR26vjC41ZWuxjgOZhVY1/LATuPozDi8aQWRB4v9yfoH/bgxG53C9 f+X37mqdvqCDQAb7yrUuNmi3ZqDim/Hgq34MfFfSMaEOhdTQAWxq/cqwZLHvRbyz7wY5Ub Ziu8XpfvAbftJkqqaiV/hVB+AFjnzn+ambnyplYjxxcz/scTZo3wvmgGdga209+onQY9IR EwnENl2XV+Kkn10eSYTxDf3J90fCf+NwYjVvwuL6+HT349VivHuiQ28SzOTB1JccXcpWCi 3SUy8iWvfKTcAWxFdGbeGUJMSxHOitp5FqTX0odc1wUDrEz8bbzH1J8F47jAtA== Date: Fri, 11 Apr 2025 15:38:40 +0200 From: Alexandre Belloni To: Alexandre Mergnat Cc: Eddie Huang , Sean Wang , Matthias Brugger , AngeloGioacchino Del Regno , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH v3 3/5] rtc: Fix the RTC time comparison issues adding cast Message-ID: <202504111338408af44d7b@mail.local> References: <20250109-enable-rtc-v3-0-f003e8144419@baylibre.com> <20250109-enable-rtc-v3-3-f003e8144419@baylibre.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250109-enable-rtc-v3-3-f003e8144419@baylibre.com> X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvudduleehucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpeffhffvvefukfhfgggtuggjsehttdertddttddvnecuhfhrohhmpeetlhgvgigrnhgurhgvuceuvghllhhonhhiuceorghlvgigrghnughrvgdrsggvlhhlohhnihessghoohhtlhhinhdrtghomheqnecuggftrfgrthhtvghrnhepgeeiudeuteehhfekgeejveefhfeiudejuefhgfeljefgjeegkeeujeeugfehgefgnecuffhomhgrihhnpegsohhothhlihhnrdgtohhmnecukfhppedvrgdtudemtggsudegmeehheeimeejrgdttdemugekjegvmedusgdusgemledtkeegmegttghftgenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpedvrgdtudemtggsudegmeehheeimeejrgdttdemugekjegvmedusgdusgemledtkeegmegttghftgdphhgvlhhopehlohgtrghlhhhoshhtpdhmrghilhhfrhhomheprghlvgigrghnughrvgdrsggvlhhlohhnihessghoohhtlhhinhdrtghomhdpnhgspghrtghpthhtohepudefpdhrtghpthhtoheprghmvghrghhnrghtsegsrgihlhhisghrvgdrtghomhdprhgtphhtthhopegvugguihgvrdhhuhgrnhhgsehmvgguihgrthgvkhdrtghomhdprhgtphhtthhop ehsvggrnhdrfigrnhhgsehmvgguihgrthgvkhdrtghomhdprhgtphhtthhopehmrghtthhhihgrshdrsghgghesghhmrghilhdrtghomhdprhgtphhtthhopegrnhhgvghlohhgihhorggttghhihhnohdruggvlhhrvghgnhhosegtohhllhgrsghorhgrrdgtohhmpdhrtghpthhtoheprhhosghhsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehkrhiikhdoughtsehkvghrnhgvlhdrohhrghdprhgtphhtthhopegtohhnohhrodgutheskhgvrhhnvghlrdhorhhg X-GND-Sasl: alexandre.belloni@bootlin.com On 11/04/2025 14:35:56+0200, Alexandre Mergnat wrote: > The RTC subsystem was experiencing comparison issues between signed and > unsigned time values. When comparing time64_t variables (signed) with > potentially unsigned range values, incorrect results could occur leading > to runtime errors. > > Adds explicit type casts to time64_t for critical RTC time comparisons > in both class.c and interface.c files. The changes ensure proper > handling of negative time values during range validation and offset > calculations, particularly when dealing with timestamps before 1970. > > The previous implementation might incorrectly interpret negative values > as extremely large positive values, causing unexpected behavior in the > RTC hardware abstraction logic. > range_max is explicitly unsigned, casting it to a signed value will break drivers. > Signed-off-by: Alexandre Mergnat > --- > drivers/rtc/class.c | 6 +++--- > drivers/rtc/interface.c | 8 ++++---- > 2 files changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c > index e31fa0ad127e9..1ee3f609f92ea 100644 > --- a/drivers/rtc/class.c > +++ b/drivers/rtc/class.c > @@ -282,7 +282,7 @@ static void rtc_device_get_offset(struct rtc_device *rtc) > * then we can not expand the RTC range by adding or subtracting one > * offset. > */ > - if (rtc->range_min == rtc->range_max) > + if (rtc->range_min == (time64_t)rtc->range_max) > return; > > ret = device_property_read_u32(rtc->dev.parent, "start-year", > @@ -299,7 +299,7 @@ static void rtc_device_get_offset(struct rtc_device *rtc) > if (!rtc->set_start_time) > return; > > - range_secs = rtc->range_max - rtc->range_min + 1; > + range_secs = (time64_t)rtc->range_max - rtc->range_min + 1; > > /* > * If the start_secs is larger than the maximum seconds (rtc->range_max) > @@ -327,7 +327,7 @@ static void rtc_device_get_offset(struct rtc_device *rtc) > * > * Otherwise the offset seconds should be 0. > */ > - if (rtc->start_secs > rtc->range_max || > + if (rtc->start_secs > (time64_t)rtc->range_max || > rtc->start_secs + range_secs - 1 < rtc->range_min) > rtc->offset_secs = rtc->start_secs - rtc->range_min; > else if (rtc->start_secs > rtc->range_min) > diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c > index aaf76406cd7d7..93bdf06807f23 100644 > --- a/drivers/rtc/interface.c > +++ b/drivers/rtc/interface.c > @@ -37,7 +37,7 @@ static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm) > */ > if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) || > (rtc->start_secs < rtc->range_min && > - secs <= (rtc->start_secs + rtc->range_max - rtc->range_min))) > + secs <= (time64_t)(rtc->start_secs + rtc->range_max - rtc->range_min))) > return; > > rtc_time64_to_tm(secs + rtc->offset_secs, tm); > @@ -58,7 +58,7 @@ static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm) > * device. Otherwise we need to subtract the offset to make the time > * values are valid for RTC hardware device. > */ > - if (secs >= rtc->range_min && secs <= rtc->range_max) > + if (secs >= rtc->range_min && secs <= (time64_t)rtc->range_max) > return; > > rtc_time64_to_tm(secs - rtc->offset_secs, tm); > @@ -66,7 +66,7 @@ static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm) > > static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm) > { > - if (rtc->range_min != rtc->range_max) { > + if (rtc->range_min != (time64_t)rtc->range_max) { > time64_t time = rtc_tm_to_time64(tm); > time64_t range_min = rtc->set_start_time ? rtc->start_secs : > rtc->range_min; > @@ -74,7 +74,7 @@ static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm) > (rtc->start_secs + rtc->range_max - rtc->range_min) : > rtc->range_max; > > - if (time < range_min || time > range_max) > + if (time < range_min || time > (time64_t)range_max) > return -ERANGE; > } > > > -- > 2.25.1 > -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com