linux-kernel - Re: Build regressions/improvements in v3.4-rc7

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

Message-ID: <CAMuHMdX13f4-3_Oe8bwZAnZpwDSV11Oxdgh--njiNGJ2KLAAww@mail.gmail.com>
Date:	Wed, 16 May 2012 17:59:56 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	James Bottomley <James.Bottomley@...senpartnership.com>
Cc:	linux-kernel@...r.kernel.org,
	Linuxppc-dev <linuxppc-dev@...abs.org>,
	Parisc List <linux-parisc@...r.kernel.org>,
	"the arch/x86 maintainers" <x86@...nel.org>,
	Dmitry Kasatkin <dmitry.kasatkin@...el.com>,
	James Morris <jmorris@...ei.org>
Subject: Re: Build regressions/improvements in v3.4-rc7

On Wed, May 16, 2012 at 4:46 PM, James Bottomley
<James.Bottomley@...senpartnership.com> wrote:
> On Wed, 2012-05-16 at 10:47 +0200, Geert Uytterhoeven wrote:
>> On Wed, May 16, 2012 at 10:30 AM, Geert Uytterhoeven
>> <geert@...ux-m68k.org> wrote:
>>   + lib/mpi/generic_mpih-mul1.c: error: inconsistent operand
>> constraints in an 'asm':  => 50:70
>>   + lib/mpi/generic_mpih-mul2.c: error: inconsistent operand
>> constraints in an 'asm':  => 49:70
>>   + lib/mpi/generic_mpih-mul3.c: error: inconsistent operand
>> constraints in an 'asm':  => 49:70
>>   + lib/mpi/mpih-div.c: error: inconsistent operand constraints in an
>> 'asm':  => 135:122, 135:371, 97:122, 106:121, 106:370, 97:371
>>
>> parisc-allmodconfig
>
> Wow, lib/mpi/ is a complete horror: it's full of hand crafted asm code.
> The error in this case appears to be that umul_ppm() is implemented as
> an xmpyu instruction.  That's a floating point instruction.  We
> deliberately compile the kernel with floating point disabled because we
> don't want to save and restore the floating point register file on each
> context switch, hence the operand constraints are unsatisfiable.

It also does fishy things on m68k, cfr. https://lkml.org/lkml/2012/3/11/22

> It appears to be completely untested on non-x86 and to have been
> imported via the security tree ... what are we supposed to do with this?
> I thought the general principle was that asm code was really supposed to
> be confined to the arch directories?

Kick it out again, or contain it in staging?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
--
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/