From owner-freebsd-arch Tue Nov 21 17:10:37 2000 Delivered-To: freebsd-arch@freebsd.org Received: from pike.osd.bsdi.com (pike.osd.bsdi.com [204.216.28.222]) by hub.freebsd.org (Postfix) with ESMTP id BF20637B4C5 for ; Tue, 21 Nov 2000 17:10:34 -0800 (PST) Received: from laptop.baldwin.cx (john@jhb-laptop.osd.bsdi.com [204.216.28.241]) by pike.osd.bsdi.com (8.11.0/8.9.3) with ESMTP id eAM1AQ082015; Tue, 21 Nov 2000 17:10:26 -0800 (PST) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Tue, 21 Nov 2000 17:10:36 -0800 (PST) From: John Baldwin To: Daniel Eischen Subject: Re: Thread-specific data and KSEs Cc: arch@FreeBSD.org, Jonathan Lemon Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 22-Nov-00 Daniel Eischen wrote: > On Tue, 21 Nov 2000, Jonathan Lemon wrote: >> On Tue, Nov 21, 2000 at 06:51:59PM -0500, Daniel Eischen wrote: >> > I'm going to start working on the user-side of the new threads >> > library. I need to be able to quickly get at the current KSE >> > (or perhaps KSEG). Can we define a register on each architecture >> > that should not be used by FreeBSD ABI compliant applications? >> > The register doesn't have to be 32 bits or larger, just large >> > enough to hold the maximum number of KSEs (or KSEGs). >> >> Um. On a i386 I'm not sure this will be practical, there aren't >> a whole lot of architecturally visible registers for use by the >> application. > > Why can't we use a segment register? %cs = code segment and is taken %ds = data segment and is taken %es = not sure, but bet it isn't safe %ss = stack, taken %fs = per-CPU data %gs ? as I mentioned in my other message, this one might be useful for addressing a structure of thread-local variables much like %fs is used for per-CPU data. It also has value in that supposedly x86-64 (aka k64) has both %fs and %gs, but no other seg regs. -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message