From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11458 Path: news.gmane.org!.POSTED!not-for-mail From: David Edelsohn Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH] s390x: Add single instruction math functions Date: Mon, 12 Jun 2017 09:28:52 -0400 Message-ID: References: <20170610182950.GV9350@port70.net> <20170610194855.GS1627@brightrain.aerifal.cx> <20170610212801.GW9350@port70.net> <20170611022044.GV1627@brightrain.aerifal.cx> <20170611101955.GX9350@port70.net> <20170612090331.GZ9350@port70.net> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Trace: blaine.gmane.org 1497274149 1374 195.159.176.226 (12 Jun 2017 13:29:09 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 12 Jun 2017 13:29:09 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-11471-gllmg-musl=m.gmane.org@lists.openwall.com Mon Jun 12 15:29:05 2017 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1dKPOx-00009K-W8 for gllmg-musl@m.gmane.org; Mon, 12 Jun 2017 15:29:04 +0200 Original-Received: (qmail 1553 invoked by uid 550); 12 Jun 2017 13:29:06 -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 1525 invoked from network); 12 Jun 2017 13:29:05 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=9XbKgzGJEqsUFu+w0eNi2Yk/ZujozXIsW5unVSDamjM=; b=q+DHQz1olgRUs6bTBwBhc/IZWyTZfb6K8IJ76CNCUlE1jjN7P7UUrIeYHDhODgDXEv lVvsd/kFOXLIBrUtojthGkWkH3nWyUAbKhF4iewS7/POAuXPUMvbS8/h27s2rj4pNKF6 etIYWHwzCxnvHQWea3EGZKjsc0WrN1rRtYqhNen/iiaM87IKjJvuH4WFsXzeHMydYBMP G2EcQ+PkYJv2dggvqH06Y3Zo4DEXzoBBMVN/xZt8+Lc9ZUayyIy9Hdx3CDm4XBmlAIgR ZJkpiiKN2Mq3zr8nKHH60h3tT3+hDdY6Fan33G5j/HB9molBR84oA9bbtwDwwY2dQ0Cl YS1g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=9XbKgzGJEqsUFu+w0eNi2Yk/ZujozXIsW5unVSDamjM=; b=CfAH45fj33atoIrJg/OA8VLazc5ReSZw9WjDewGWW7WkH2hX0b1TBYoW+11KtE+LXL wDB3//Es5I+oZFZTWm+2PCVyQ2i1qbTeu+rwfdFVQtfQFMvfxWQZ98K53HYPxhZ20EdE xHD2QFtjLMJGAXC1KllnsNvfabrzqKXYSrIakw8RQWanVgLkVFn2ExW4ke6erzMqPc0K tLHe+GcDYanrYUyQgNAcFwBNKW6nmngBKlHlz52++9twkR7jUC/gqTJ2GfIQF27byBnw 19wfX5uK7MEJZbt40+S5z5O5rII32nnnf12eQiTDcehD8zeVDTJQ10RVBmG7i85rQvjX 9FGA== X-Gm-Message-State: AKS2vOxBHISzWZpelFfc163Zs8gUXjIfk3oNF4byI8OBEfI6RXbXZ/s0 f5drOqRBAQ2iZqT6sd6mN9atrM1W4w== X-Received: by 10.55.162.145 with SMTP id l139mr38922509qke.162.1497274132640; Mon, 12 Jun 2017 06:28:52 -0700 (PDT) In-Reply-To: <20170612090331.GZ9350@port70.net> Xref: news.gmane.org gmane.linux.lib.musl.general:11458 Archived-At: On Mon, Jun 12, 2017 at 5:03 AM, Szabolcs Nagy wrote: > * David Edelsohn [2017-06-11 22:46:09 -0400]: > >> On Sun, Jun 11, 2017 at 6:19 AM, Szabolcs Nagy wrote: >> > * Rich Felker [2017-06-10 22:20:44 -0400]: >> >> On Sat, Jun 10, 2017 at 05:48:05PM -0400, David Edelsohn wrote: >> >> > When I worked with Bobby Bingham to create the s390x port of Musl, I >> >> > said that he could assume newer processors. Also, I don't believe >> >> > that LLVM supports the earlier processors. I believe that he assumed >> >> > some more recent instructions in other parts of the code. >> >> >> >> That seems doubtful; the amount of asm in musl is minimal and unlikely >> >> to benefit from later ISA levels; all the instructions I see look like >> >> very basic stuff that would always have been available. >> >> >> >> Now, what likely is accurate is your claim that nobody is using musl >> >> on lower ISA levels, so maybe it doesn't matter. >> > >> > well i am using s390x musl with lower isa level for compile tests >> > >> > and it seems gas rejects unrecognized opcodes so the new inline >> > asm does not compile for me. >> > >> > i think either musl configure should make sure the cc targets >> > the right isa level or the code should handle it with ifdefs >> >> I have asked the IBM toolchain team how to distinguish the >> architecture level at compile time, or at least distinguish support >> for the FP rounding instruction. >> >> Are you actually running s390x musl on a system earlier than z196 >> architecture level? The public IBM LinuxONE Cloud is running on a z13 >> system, many generations newer than even z196. >> > > no, i only have a cross compiler, but since the toolchain build script > uses default settings i get z900 arch, if that's not good then gcc > config default should be fixed for musl. > >> The following IBM table of supported and tested systems >> >> https://www-03.ibm.com/systems/z/os/linux/resources/testedplatforms.html >> >> shows that RHEL 7 and SLES 12 require at least z196, and Ubuntu 16.04 >> requires at least zEC12. >> >> I can't find any official hardware requirements description for Alpine >> Linux. I tend to doubt that user would run it on older hardware, >> especially hardware no longer supported by other, modern Linux >> distributions. >> >> Building musl libc on older hardware is a nice accomplishment, but >> investing effort and complexity to maintain support probably isn't >> useful to any musl libc user and probably isn't a productive use of >> developer resources. >> >> I will continue to inquire if there is a simple technique to accomplish this. Apparently GCC 7.1 added architecture macros. As Tuan referenced, Alpine Linux also requires z196 as the minimum architecture level. I believe that it would be better for s390-musl to default to z196 ISA than musl to require GCC 7.1. Thanks, David