linux-kernel - Re: [PATCH/RFC] Math-emu kills the kernel on Athlon64 X2

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]

Date:	Tue, 3 Oct 2006 09:23:39 -0700
From:	Randy Dunlap <rdunlap@...otime.net>
To:	Linus Torvalds <torvalds@...l.org>
Cc:	akpm <akpm@...l.org>, Jesper Juhl <jesper.juhl@...il.com>,
	Andi Kleen <ak@...e.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH/RFC] Math-emu kills the kernel on Athlon64 X2

On Tue, 3 Oct 2006 08:10:07 -0700 (PDT) Linus Torvalds wrote:

> 
> 
> On Mon, 2 Oct 2006, Randy Dunlap wrote:
> > 
> > OK, how about something more direct and less obtrusive, like this?
> 
> I think this is fine, but I also think it's a bit hacky.
> 
> Wouldn't it make more sense to make the whole "nofxsr" thing just clear 
> the capability, ie just a diff like the appended...
> 
> Does that work for you? If so, we should _also_ make sure that "no387" 
> calls this function too, so that you don't have to do _both_ no387 and 
> nofxsr, which is clearly silly. Once you do no387, the kernel should do 
> the nofxsr for you, methinks..

Yes, that works.

> ---
> diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
> index 2799baa..7ac3c9e 100644
> --- a/arch/i386/kernel/cpu/common.c
> +++ b/arch/i386/kernel/cpu/common.c
> @@ -185,6 +185,7 @@ static void __cpuinit get_cpu_vendor(str
>  static int __init x86_fxsr_setup(char * s)
>  {
>  	disable_x86_fxsr = 1;
> +	clear_bit(X86_FEATURE_FXSR, boot_cpu_data.x86_capability);
>  	return 1;
>  }
>  __setup("nofxsr", x86_fxsr_setup);

---
~Randy
-
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/