From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtpout.efficios.com (smtpout.efficios.com [167.114.26.122]) by sourceware.org (Postfix) with ESMTPS id 358EE3858D1E for ; Wed, 1 Nov 2023 14:45:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 358EE3858D1E Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=efficios.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 358EE3858D1E Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=167.114.26.122 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1698849922; cv=none; b=MMAqtU66facDbU3kgH5Xb5/IwgtpDj5xp7KXspBh1gVq010bZYTpwRCR2i0O1zkkeLXAsAM+blKZS0fWHnZgWJmnqP4U9mPyF6zbWHFepO86KgA22WOevW4K0rlgNJVqMSIEGi5ZjsZ3+kyZ95ZUr8PDsL6l+t8V/G3Ab5ZQcpQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1698849922; c=relaxed/simple; bh=iUM18SOrjsOKJPR8RET+UokeWHFO2eiuOSHYCtN08zA=; h=DKIM-Signature:Message-ID:Date:MIME-Version:Subject:To:From; b=Gpglx0HXKIVGa7jyN1as0+WI3k7JCNsnIyaoLTpCnc4W8d3I5q8r/zwV+0e+EBWTrK0PzgHlkctwh2xjGRaRM2rfi3KMYXFZao/LIytSpgsEjjhMjYbJotkJxqGuYwjWDRo8S9xoxORjvfGuTXHlLcO4G8YPNhRyQpfrUp4XUkA= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=efficios.com; s=smtpout1; t=1698849910; bh=iUM18SOrjsOKJPR8RET+UokeWHFO2eiuOSHYCtN08zA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=bt/VirqKWqMtELU6882j71HbEpX+d42AcbdOCHw22ayVQBs1YG0jbTLIw6mLbKyYN Ks0NTdrIpR9jAq5E9j0I3WTLVRJ6xyPfmhyoujh/sfrBGNMdQYeW5Bgqd6bAERKTg0 Od2j0KSgNS3RVOz6SLzyUSXBVm79qqvtJICjXZMvCcZOOEnlrWRWNb8+N10t/L67Mo eeUJfbbfq/hSvJEA2pgwMRJwu3rsvNqBYgw3makcFXTVMhvl/gkJp+pXjwIJ2EcX8X 578iaG6zH8hamrQJcDs6vCpC51chY96lW9+R8FFBB21t2xuz1p8U9VHqXjNxoa6ErZ and+KoS3rf6SA== Received: from [172.16.0.134] (192-222-143-198.qc.cable.ebox.net [192.222.143.198]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4SL8tZ1cK4z1Ztk; Wed, 1 Nov 2023 10:45:10 -0400 (EDT) Message-ID: <1c5b9ef4-f241-4577-838e-37f0104a6a7c@efficios.com> Date: Wed, 1 Nov 2023 10:45:29 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: GNU libc support for extensible rseq ABI Content-Language: en-US To: Florian Weimer , Michael Jeanson Cc: "carlos@redhat.com" , libc-alpha References: <87o7mhms3v.fsf@mid.deneb.enyo.de> From: Mathieu Desnoyers In-Reply-To: <87o7mhms3v.fsf@mid.deneb.enyo.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 2023-05-18 14:06, Florian Weimer wrote: > * Mathieu Desnoyers: > >> Hi Carlos, Florian, >> >> Now that the 6.3 Linux kernel is out, the ABI for extensible rseq is >> frozen, and we could add support for it in glibc. It would be good to >> upstream this support before we run out of room in the padding space we >> currently re-use. >> >> What glibc release should we target for this ? > > It may be possible to hack this into the existing TLS allocator. See > the loop in _dl_determine_tlsoffset. It should be possible to add the > rseq area as another static TLS block (perhaps as the first one before > the loop), with the size and alignment requested by the kernel. If we > can make that work, it's going to be a fairly small patch that should > be backportable as well. That could go into 2.38 or 2.39. > > If we need a new TLS allocator, it's definitely 2.39 material at this > point, potentially later. Michael (in CC) showed interest in working on this. I'm adding him to this e-mail thread so you are both aware of each other's ongoing progress. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com