linux-kernel - Re: [uml-devel] [PATCH] checkstack: use $UTS

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: <CALYGNiNSFoW6Z_1o3JfV-cCeay1QmTptrt4kWHVegkuw+-6A8A@mail.gmail.com>
Date:	Tue, 8 Jul 2014 12:30:17 +0400
From:	Konstantin Khlebnikov <koct9i@...il.com>
To:	Richard Weinberger <richard@....at>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	"x86@...nel.org" <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	UML devel <user-mode-linux-devel@...ts.sourceforge.net>,
	linux-kbuild <linux-kbuild@...r.kernel.org>
Subject: Re: [uml-devel] [PATCH] checkstack: use $UTS_MACHINE as target architecture

On Tue, Jul 8, 2014 at 12:20 PM, Richard Weinberger <richard@....at> wrote:
> Am 08.07.2014 10:16, schrieb Konstantin Khlebnikov:
>> On Tue, Jul 8, 2014 at 12:01 PM, Richard Weinberger
>> <richard.weinberger@...il.com> wrote:
>>> On Tue, Jul 8, 2014 at 7:48 AM, Konstantin Khlebnikov <koct9i@...il.com> wrote:
>>>> On Tue, Jul 8, 2014 at 2:05 AM, Andrew Morton <akpm@...ux-foundation.org> wrote:
>>>>> On Sat, 05 Jul 2014 15:22:38 +0400 Konstantin Khlebnikov <koct9i@...il.com> wrote:
>>>>>
>>>>>> This fixes command # make checkstack for i386/x86_64.
>>>>>> Looks like $UTS_MACHINE is exactly what scripts/checkstack.pl needs.
>>>>>>
>>>>>> By default $UTS_MACHINE is equal to $ARCH, but some arch/${ARCH}/Makefile
>>>>>> overrides it. This patch updates it also in arch/x86/Makefile.um
>>>>>>
>>>>>> broken in ffee0de ("x86: Default to ARCH=x86 to avoid overriding CONFIG_64BIT")
>>>>>
>>>>> The changelog doesn't describe the bug which is being fixed.  It should
>>>>> do so please.  If there are any compiler/make error messages then those
>>>>> should be included.
>>>>>
>>>>
>>>> Oh, ok. checkstalk.pl needs either i386 or x86_64, x86 isn't enough.
>>>>
>>>> $ make checkstack
>>>> objdump -d vmlinux $(find . -name '*.ko') | \
>>>> perl /home/blind/src/linux-stable/scripts/checkstack.pl x86
>>>> wrong or unknown architecture "x86"
>>>
>>> And now we need ARCH, SUBARCH and UTS_MACHINE on UML? :-(
>>
>> Nope UTS_MACHINE is autodetected, see hunk Makefile.x86 in my patch.
>>
>> I thought about cleaning this part of UML.
>> For example we could move arch/x86/um into arch/um/x86 and use # make
>> ARCH=um/x86
>
> No way. We moved the x86 stuff to arch/x86/ a few Years ago by design.

Ok, fine. We could leave it in arch/x86/um and use make ARCH=x86/um

>
>> after collecting this stuff together it woud be easier to get rid of
>> forever-broken parts.
>> As I see UML has been designed to work everywhere but SMP seem never worked
>> as well as any host os except of linux or other arch except x86.
>
> Currently UML runs only on x86_32/64.
> Adding/fixing SMP support should be doable.

This might be quite difficult on top of current ptrace-based design.
I thought about running userspace in kvm context, this might be much
faster than ptrace but requires indirect uaccess like for 4gb-split.
But it's very unlikely that I'll find time for that.

>
> Thanks,
> //richard
--
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/