From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 00201EDEBF5 for ; Tue, 3 Mar 2026 21:01:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:Message-ID:References:In-Reply-To:Subject:CC:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=VYCoMox874UkG41AFwcqLA/NfPlaOlGxygnVG+NrNEI=; b=jteVeDoiVLKYtPfgTOmMHaxTGQ /B4rwcLrNYBYjyvMAJ2724HqyYhBWLWjrNVzptfSLv0ZTpAOBbHrV3AWuVu03mZJT938xGTFpLFVn QQzfp0zUT8YqKbRnfMiM4167K5eBj2OLM9Yl7qS6TPiWbDlEua1JvXmP79hkCrNSbL6jwmSo9kPGC 8CDgqE4nfJTSr84tPcXIe7sPOHe7yBkf4Esr1N1A/mWfAsODxZ3OpKP82EfiPBJ1jmtWNvsJHOpDP op47PeGwwnvJRf4qxIw65R4M2WMRSj4sXkCh0qoP0LKCH+OdwEd2HD6CqQ+jOSoQry0V5hFpvU3me LHmaNESw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vxWrY-0000000FwFv-14mG; Tue, 03 Mar 2026 21:01:04 +0000 Received: from terminus.zytor.com ([2607:7c80:54:3::136] helo=mail.zytor.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vxWrV-0000000FwEp-3Ybp for linux-arm-kernel@lists.infradead.org; Tue, 03 Mar 2026 21:01:03 +0000 Received: from ehlo.thunderbird.net (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 623L07cW3276874 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 3 Mar 2026 13:00:08 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 623L07cW3276874 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2026022301; t=1772571609; bh=VYCoMox874UkG41AFwcqLA/NfPlaOlGxygnVG+NrNEI=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=J04tWHXJRQ4G1vgUJxAr5RbvTbGLR/cHWVslG2ysvgZVqum75IEoDC6dtGc3RlEKN gUgGPOAd9MXe8CpG/crlLctiNQxJBMOT+cXYXjrFtYd/ntsm2/P8UIzdSo2DMS6ark Vu3+lFth/GOPA8muhWjcE1ynqs1UpAoaFJpUajmj+BiMnuK0U4mSRCtSZ1GIIeuvIa mZ97PzkWn/kLprWX0cl5Mi4+xj7F5yQHjWd+WIjcipqFzUiIDQhiPDGeAseJOqICmR WDrvasLJ1NsDoRQE3mNCnwQHbwWCc38WW8I2ZcCDD1Zk0XtigDVyZiABIDdAPpUE/W EQp9NarHAcRQQ== Date: Tue, 03 Mar 2026 13:00:02 -0800 From: "H. Peter Anvin" To: Arnd Bergmann , =?ISO-8859-1?Q?Thomas_Wei=DFschuh?= CC: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Russell King , Catalin Marinas , Will Deacon , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Thomas Bogendoerfer , Vincenzo Frascino , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org Subject: Re: [PATCH 1/7] x86/vdso: Respect COMPAT_32BIT_TIME User-Agent: K-9 Mail for Android In-Reply-To: <2b1ac7b9-fcc8-4aa3-a0ad-eb37e4bce030@app.fastmail.com> References: <20260227-vdso-compat_32bit_time-v1-0-3f0286a7bac3@linutronix.de> <20260227-vdso-compat_32bit_time-v1-1-3f0286a7bac3@linutronix.de> <03cd1e21-a2f2-46a1-a674-cbaef9712016@app.fastmail.com> <20260227103226-cc3bb32c-0107-4c09-b81a-ca33ea03ad5c@linutronix.de> <49b7c9f9-198a-49f7-880b-6ae74d7bd985@zytor.com> <2b1ac7b9-fcc8-4aa3-a0ad-eb37e4bce030@app.fastmail.com> Message-ID: <56591FD5-0DD0-4117-BC7B-4565E3F6512E@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260303_130101_890674_3276974B X-CRM114-Status: GOOD ( 17.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On March 3, 2026 12:50:33 PM PST, Arnd Bergmann wrote: >On Tue, Mar 3, 2026, at 19:11, H=2E Peter Anvin wrote: >> On 2026-02-27 01:34, Thomas Wei=C3=9Fschuh wrote: >>>>> >>>> The thing about gettimeofday() and time() is that they don't have >>>> a 64-bit version and libc implementations are expected to call >>>> clock_gettime() instead=2E The result was that there was never a >>>> patch to turn the off either=2E >>>=20 >>> gettimeofday() is currently the only way to get the timezone of the ke= rnel=2E >>> But I guess this is a legacy thing anyways=2E If you say we should dro= p it, >>> let's drop it=2E >>>=20 >> >> The time zone in the kernel has never worked anyway, as it would requir= e the >> kernel to contain at least the forward portion of the zoneinfo/tzdata t= able in >> order to actually work correctly=2E The only plausible use of it would = be for >> local time-based filesystems like FAT, but I don't think we bother=2E >> >> A bigger question is whether or not we should omit these from the vDSO >> completely (potentially causing link failures) or replace them with stu= bs >> returning -ENOSYS=2E > >I see no harm in keeping gettimeofday() in the vdso when >COMPAT_32BIT_TIME is turned on, as existing code will call it >no matter whether it's in the vdso or the syscall=2E > >Equally, I see no point in having either version of >gettimeofday() or settimeofday() when COMPAT_32BIT_TIME is >disabled, as clearly anything calling it would pass incorrect >data for times past 2038=2E > >Neither glibc nor musl support actually returning the kernel >timezone to callers of gettimeofday in modern versions that >support time64 syscalls=2E > > Arnd > That wasn't the point=2E The point was what kind of error behavior we want= =2E