linux-kernel - Re: [PATCH 2/4] rtc: s3c: Add time range

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Thu, 21 Oct 2021 22:55:02 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Sam Protsenko <semen.protsenko@...aro.org>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        linux-rtc@...r.kernel.org,
        Linux Samsung SOC <linux-samsung-soc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/4] rtc: s3c: Add time range

On 21/10/2021 22:48:51+0300, Sam Protsenko wrote:
> After testing thoroughly, I can confirm that Alexandre is right about
> leap years (Exynos850 RTC treats both 2000 and 2100 as leap years).
> And it also overflows internally on 2159 year, limiting the actual
> time range at 160 years. So I'll keep that range at 100 years for all
> RTCs. As Krzysztof said, there is no practical reasons in trying to
> increase it anyway. Will send v2 soon.
> 
> What I'm curious about is RTC testing. I've found this test suite:
> 
>     tools/testing/selftests/rtc/rtctest.c
> 
> But it doesn't seem to cover corner cases (like checking leap years,
> which was discussed here). Just a thought: maybe it should be added
> there, so everyone can benefit from that? For example, I know that in
> Linaro we are running LKFT tests for different boards, so that might
> theoretically reveal some bugs. Though I understand possible
> implications: we probably don't know which ranges are supported in
> driver that's being tested. Anyway, just saying.
> 

Sorry, I should have pointed to:
https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/rtc-tools.git/tree/rtc-range.c

This does check for the actual range of an RTC.


-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com