Re: Bug#164766: Problem with VIA C3 chip and libcrypto
- To: GOTO Masanori <email@example.com>
- Cc: Philip Blundell <firstname.lastname@example.org>, David Goodenough <email@example.com>, Christoph Martin <firstname.lastname@example.org>, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org
- Subject: Re: Bug#164766: Problem with VIA C3 chip and libcrypto
- From: Daniel Jacobowitz <email@example.com>
- Date: Fri, 17 Jan 2003 10:29:03 -0500
- Message-id: <20030117152903.GA9588@nevyn.them.org>
- Mail-followup-to: GOTO Masanori <firstname.lastname@example.org>, Philip Blundell <email@example.com>, David Goodenough <firstname.lastname@example.org>, Christoph Martin <email@example.com>, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com
- In-reply-to: <firstname.lastname@example.org>
- References: <E187ksI-0004XZ-00@Beacon.Phantasia.org> <200211051503.gA5F3XR3029358@mailgate3.zdv.Uni-Mainz.DE> <3E229873.email@example.com> <E18Y2tm-0003Orfirstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <email@example.com>
On Fri, Jan 17, 2003 at 09:39:44AM +0900, GOTO Masanori wrote:
> At 16 Jan 2003 18:38:07 +0000,
> Philip Blundell wrote:
> > So, per our IRC discussion this afternoon, I think the current plan for
> > this is to have ld.so treat CMOV as an optional extension, similar to
> > how MMX is handled. In other words:
> > - Add CMOV to HWCAP_IMPORTANT in glibc.
> > - Ask the maintainers of openssl and any other affected packages to put
> > their cmov-using libraries in /lib/i686/cmov.
> > - If openssl wants to ship a specific C3-compatible build that only
> > uses mandatory i686 features, it can go in /lib/i686.
> Thanks Philip for summarizing.
> We debian-glibc team plan to prepare cmov-aware libc6.
> To make sure for other people, I add some more words.
> This libc ld.so special handling for hardware capability is used by
> only MMX currently. We expand it not only for MMX but also CMOV.
> MMX, intel's multi media extension, is also same circumstance that
> both Pentium (i586) and Pentium MMX (i586 MMX) are 'i586 class
This bit is a good idea but...
> Well, his stance is not wrong.
> We can hack gcc not to generate CMOV code with (for example) -mcpu=c3,
> or -mno-cmov (like -mno-mmx), but stil this hardware capability
> handling is needed for dynamic libraries.
> In addition, We don't provide any cmov checking for 'binaries which
> are hand-assembled or gcc generated'. Hand-assembled binaries should
> check cmov flag like mmx. If you get 'illegal instruction' with such
> binaries, you submit BTS for such packages. It's another issue that a
> binary is optmized as i686 with cmov instruction by gcc. You need to
> consider how to fix. I anticipate that it may need to make gcc
> non-cmov aware.
Let's not do anything about this until someone gets clarification from
GCC that -march=i686 is not actually supposed to be a 686, OK?
MontaVista Software Debian GNU/Linux Developer