From owner-svn-src-head@freebsd.org Fri Oct 28 17:05:40 2016 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C90DAC254B0; Fri, 28 Oct 2016 17:05:40 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from mail.baldwin.cx (bigwig.baldwin.cx [96.47.65.170]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id A4C40F52; Fri, 28 Oct 2016 17:05:39 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from ralph.baldwin.cx (c-73-231-226-104.hsd1.ca.comcast.net [73.231.226.104]) by mail.baldwin.cx (Postfix) with ESMTPSA id B76CF10AF93; Fri, 28 Oct 2016 13:05:38 -0400 (EDT) From: John Baldwin To: Konstantin Belousov Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r307971 - head/sys/mips/include Date: Fri, 28 Oct 2016 09:59:26 -0700 Message-ID: <4639059.6gemL8B1hY@ralph.baldwin.cx> User-Agent: KMail/4.14.10 (FreeBSD/11.0-PRERELEASE; KDE/4.14.10; amd64; ; ) In-Reply-To: <20161028153158.GD54029@kib.kiev.ua> References: <201610261737.u9QHb8Ps036831@repo.freebsd.org> <11698910.Akp5I7OyZ5@ralph.baldwin.cx> <20161028153158.GD54029@kib.kiev.ua> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.4.3 (mail.baldwin.cx); Fri, 28 Oct 2016 13:05:38 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.99.2 at mail.baldwin.cx X-Virus-Status: Clean X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Oct 2016 17:05:40 -0000 On Friday, October 28, 2016 06:31:58 PM Konstantin Belousov wrote: > On Thu, Oct 27, 2016 at 03:08:01PM -0700, John Baldwin wrote: > > On Wednesday, October 26, 2016 05:37:08 PM John Baldwin wrote: > > > Author: jhb > > > Date: Wed Oct 26 17:37:08 2016 > > > New Revision: 307971 > > > URL: https://svnweb.freebsd.org/changeset/base/307971 > > > > > > Log: > > > Correct definition of 'struct sigcontext' on MIPS. > > > > > > Add missing fields ('sr' and 'mc_tls') to 'struct sigcontext'. > > > > > > The kernel doesn't use 'struct sigcontext' but instead uses 'ucontext_t' > > > which includes 'mcontext_t' in 'struct sigframe' to build the signal frame. > > > As a result, this change is not an ABI change but simply making > > > 'struct sigcontext' correct. Note that 'struct sigcontext' is only used > > > for "Traditional BSD style" signal handlers. > > > > > > While here, rename the 'xxx' field to '__spare__' to match 'mcontext_t'. > > > > > > Sponsored by: DARPA, AFRL > > > > We should perhaps a static assertion somewhere that > > sizeof(sigset_t) + sizeof(ucontext_t) == sizeof(struct sigcontext) if > > that is really true of all of our architectures. > This should be mcontext_t instead of ucontext_t. Yes. I will try adding that static assert to sys/kern/kern_sig.c and seeing if it survives a universe build. > > Alternatively, we might consider retiring 'struct sigcontext' altogether. > > It's purpose has been superseded by SA_SIGINFO (which is more portable) > > which has been around for quite a while now. As a first step I guess > > we could try an exp-run with 'struct sigcontext' removed. (We should > > have ditched this in 5.0 since we have a separate sendsig/sigreturn path > > for FreeBSD 4.x already. Oh well.) > > I do not think that this is a practical option. I know that struct > sigcontext is used by nongnu libunwind. Quick search identifies mono and > go as consumers as well. Well, we could perhaps patch those to use SA_SIGINFO instead, but if it's a non-trivial amount of effort I'm not going to bother. I'm surprised that some of those would use sigcontext. Both mono and go post-date SA_SIGINFO being standardized and supported on FreeBSD AFAIK. Supporting sigcontext just means extra BSD-specific code in those applications compared to using SA_SIGINFO. :-/ -- John Baldwin