From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/9910 Path: news.gmane.org!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH v2] add powerpc64 port Date: Thu, 14 Apr 2016 15:14:00 -0400 Message-ID: <20160414191400.GZ21636@brightrain.aerifal.cx> References: <1459747571-9123-1-git-send-email-koorogi@koorogi.info> <20160413230506.GE22574@port70.net> <20160414080138.GA23694@dora.lan> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1460661259 12681 80.91.229.3 (14 Apr 2016 19:14:19 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 14 Apr 2016 19:14:19 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-9923-gllmg-musl=m.gmane.org@lists.openwall.com Thu Apr 14 21:14:19 2016 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1aqmiY-0007Xb-Ck for gllmg-musl@m.gmane.org; Thu, 14 Apr 2016 21:14:18 +0200 Original-Received: (qmail 3634 invoked by uid 550); 14 Apr 2016 19:14:16 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 3610 invoked from network); 14 Apr 2016 19:14:15 -0000 Content-Disposition: inline In-Reply-To: <20160414080138.GA23694@dora.lan> User-Agent: Mutt/1.5.21 (2010-09-15) Original-Sender: Rich Felker Xref: news.gmane.org gmane.linux.lib.musl.general:9910 Archived-At: On Thu, Apr 14, 2016 at 03:01:38AM -0500, Bobby Bingham wrote: > On Thu, Apr 14, 2016 at 01:05:07AM +0200, Szabolcs Nagy wrote: > > * Bobby Bingham [2016-04-04 00:26:11 -0500]: > > > +++ b/arch/powerpc64/bits/setjmp.h > > > @@ -0,0 +1 @@ > > > +typedef unsigned long long __jmp_buf[66]; > > > > hm glibc seems to use long[64] with 16byte alignment, > > is the size diff because of alignment? > > Yes. Though apparently the glibc setjmp asm has code to detect a > misaligned jmp_buf, but its handling of that case ends up overflowing > the jmp_buf. > > I can make some changes to get our jmp_buf down to 65, but the only ways > to get it down to 64 are either with 16 byte alignment, or to have setjmp > spill vector registers to the stack first so it can copy them from there > to the jmp_buf through a gpr. > > How important is it to match glibc here? I think you could avoid the need for alignment or increased buffer size by positioning the vector registers at jmp_buf_end-vector_save_size rounded _down_ to alignment, then positioning the grps around them (so, putting the last gpr at the end rather than before the vectors if the buffer as a whole is misaligned). But it might be preferable to have the alignment match ABI too. Is there any way it can be achieved with just things guaranteed to exist by the psABI (is __int128 required by the psABI?) or does it require C11 and/or GNUC attributes to get 16-byte alignment? Rich