From owner-freebsd-current@FreeBSD.ORG Tue Jun 17 15:46:17 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id EB40D37B401 for ; Tue, 17 Jun 2003 15:46:17 -0700 (PDT) Received: from ns1.xcllnt.net (209-128-86-226.BAYAREA.NET [209.128.86.226]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1A14A43F93 for ; Tue, 17 Jun 2003 15:46:17 -0700 (PDT) (envelope-from marcel@xcllnt.net) Received: from ns1.xcllnt.net (localhost [127.0.0.1]) by ns1.xcllnt.net (8.12.9/8.12.9) with ESMTP id h5HMjjDZ057821; Tue, 17 Jun 2003 15:45:45 -0700 (PDT) (envelope-from marcel@ns1.xcllnt.net) Received: (from marcel@localhost) by ns1.xcllnt.net (8.12.9/8.12.9/Submit) id h5HMjj3w057820; Tue, 17 Jun 2003 15:45:45 -0700 (PDT) Date: Tue, 17 Jun 2003 15:45:45 -0700 From: Marcel Moolenaar To: Julian Elischer Message-ID: <20030617224545.GC57040@ns1.xcllnt.net> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.1i cc: FreeBSD current users Subject: Re: __thread support in -current.. X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Jun 2003 22:46:18 -0000 On Tue, Jun 17, 2003 at 03:34:15PM -0700, Julian Elischer wrote: > > Ok, so having thrashed out what is required on the threads list > (and severely strained (but hopefully not permanently) our relations > with the OpenGL folks) we've figured out that we do need to support > __thread (if we don't we'll miss out on alot). > > I have basicaly worked out what we need to do > (Generarlly we do the same as solaris does) to support this.. > The question is, what do we need to do for gcc and the loader > to support this..? > > I guess the support is in gcc as Linux and solaris use it, but > is our linker close enough to what they use to be able to benefit at all > from them? >From my posting to threads@: \begin{quote} ... To support the __thread keyword, our thread library needs to create the TLS as defined in the binary and its dependent shared libraries by virtue of the .tdata and .tbss sections/segments, based on the image of the TLS as constructed by the RTLD for the initial set of modules (created for the initial thread) and amended by TLS space defined in the dynamicly loaded libraries; and the TLS has to be created for every new thread at the time the thread itself is created. This TLS allocation has to be made accessable in accordance with runtime specifications for the supported architectures (libthr: i386 & ia64; libkse: i386 currently -- more to follow) and in line with the access sequences created by the compiler, and using the static relocations known to the static linker and dynamic relocations of which the support needs to be added to RTLD. The static TLS model requires the least amount of work: add support to allocate the TLS image for every thread creation and point the thread pointer to it in a way compatible with the runtime spec. The dynamic TLS model requires more substantial changes and involves RTLD as well. This is the model that requires __tls_get_addr(). \end{quote} HTH, -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net