linux-kernel - Re: Setup code crashes my old 486 box

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: <48A2155B.1020904@zytor.com>
Date:	Tue, 12 Aug 2008 15:57:31 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Joerg Roedel <joro@...tes.org>
CC:	mingo@...hat.com, tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: Setup code crashes my old 486 box

Joerg Roedel wrote:
> Hello,
> 
> yesterday I tried to reactivate my old 486 box and wanted to install a
> current Linux with latest kernel on it. But it turned out that the
> latest kernel does not boot because the machine crashes early in the
> setup code.
> After some debugging it turned out that the problem is the query_ist()
> function. If this interrupt with that function is called the machine
> simply locks up. It looks like a BIOS bug. Looking for a workaround for
> this problem I wrote the attached patch. It checks for the CPUID
> instruction and if it is not implemented it does not call the speedstep
> BIOS function. As far as I know speedstep should be available since some
> Pentium earliest.
> Is this an acceptable workaround or is there a better one for this?
> 
> Regards,
> 
> Joerg

Right in concept, but I dislike the implementation (duplication of the 
CPU detect code we already have).  Could you try this patch and see if 
it works for you?

	-hpa

View attachment "diff" of type "text/plain" (1464 bytes)