linux-kernel - Re: [PATCH linux-next] Documentation: Build mic/mpssd only for x86

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CALZtONA2uk7ZN=f5S-DnmcOwhqtzLXmppk48YqfgjwA+vQuhtw@mail.gmail.com>
Date:	Fri, 5 Dec 2014 14:53:40 -0500
From:	Dan Streetman <ddstreet@...e.org>
To:	Ashutosh Dixit <ashutosh.dixit@...el.com>
Cc:	Jonathan Corbet <corbet@....net>, Jiri Kosina <jkosina@...e.cz>,
	Peter Foley <pefoley2@...oley.com>,
	Randy Dunlap <rdunlap@...radead.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jennings <sjennings@...iantweb.net>,
	"Yokoyama, Caz" <caz.yokoyama@...el.com>,
	"Dutt, Sudeep" <sudeep.dutt@...el.com>,
	"Chandramouli, Dasaratharaman" 
	<dasaratharaman.chandramouli@...el.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
	"Rao, Nikhil" <nikhil.rao@...el.com>,
	Daniel Borkmann <dborkman@...hat.com>,
	"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
	Siva Yerramreddy <yshivakrishna@...il.com>
Subject: Re: [PATCH linux-next] Documentation: Build mic/mpssd only for x86_64

On Fri, Dec 5, 2014 at 1:18 PM, Ashutosh Dixit <ashutosh.dixit@...el.com> wrote:
> On Thu, Dec 04 2014 at 07:27:06 PM, Dan Streetman <ddstreet@...e.org> wrote:
>> On Thu, Dec 4, 2014 at 4:27 PM, Ashutosh Dixit <ashutosh.dixit@...el.com> wrote:
>>> mic/mpssd along with MIC drivers are currently only usable on
>>> x86_64. So build mic/mpssd only for x86_64 to avoid build breaks on
>>> big-endian systems.
>>
>> Only building for x86_64 is fine, but in that case what's the point of
>> leaving the htole16() et. al. functions in mpssd.c?  Shouldn't they be
>> removed?
>
> I am hoping that once glibc is fixed we can remove this limitation on
> building only for x86_64, so I'd rather htole16() et. al. stayed.

FYI, the bug I opened with glibc:
https://sourceware.org/bugzilla/show_bug.cgi?id=17679

was rejected because Andreas states "C does not allow function calls
in file scope."  The suggestion was made to try to fix gcc, but
honestly I don't have the time (or energy) to push for a gcc change
just for this. :-)

I do think it's too bad that glibc hto* functions don't work in file
scope (i.e. with static/global var initialization) for constant values
(using them with variables is different, which is why
__bswap_constant_* works in file scope but __bswap_* doesn't), since
it's simply a 2-step process that's entirely doable by the
preprocessor and/or compiler; just check if target endianness matches
desired endianness, and if not the compiler does a simple byte swap of
the constant value.

Anyway, I doubt glibc and/or gcc will be updated anytime soon to allow this.

>  As I
> said earlier, I'm fine with your patch too, but restricting the build
> for x86_64 seems to be the smallest patch which provides an acceptable
> solution.

Fine with me too.  It'll get big-endian building again.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/