On Tue, 11 Nov 1997, Andre Derrick Balsa wrote:
> Hi,
>
> Jason Burrell wrote:
> ...
> > I did that last night when a friend using BSD couldn't get Alan's code to
> > compile. This following code just loops indefinately on my P133 with a
> > stepping of 12 regardless of what user executes it.
>
> WRONG!!! The code below is the example *I* posted to the linux-kernel
> list to test the Cyrix bug. In case you wondered, the four hex codes in
> array c are the letters "Cyri".
[snip]
> At least it was copied correctly... Next time please name the source.
I did. Well, I named where I got it from, anyway. Where the second-hand
poster, in this case Alan, got it from I have little way to know. I
assumed it was his and didn't check the URL given. See below.
[snip]
> That's a genuine Intel Pentium with the genuine F0 bug. Try again with
> the code posted by Richard B. Johnson.
Actually, the original poster asked if your code nailed a Pentium given
some of the other bugs the P5 has. I tried it, and it didn't. The "F00F"
code kills my processor as advertised.
Here's the original posting to BUGTRAQ:
Date: Sat, 8 Nov 1997 23:50:37 +0000
From: Alan Cox <alan@LXORGUK.UKUU.ORG.UK>
To: BUGTRAQ@NETSPACE.ORG
Subject: Re: WARNING: Linux Intel Pentium Bug
> This code does NOT affect Cyrix 6x86 (166+ specifically, but probably
all of
> them) processors. If you run a multiuser, untrusted system, I suggest
> reserving some at your local computer supplier... unless there is an
easy
> fix for this, there is going to be a run on them.
I doubt it; See
http://www.heise.de/ct/art_ab97/9713030/
static unsigned char c[4] = {0x36, 0x78, 0x38, 0x36};
main()
{
asm ("movl $c, %ebx\n\t"
"again: xchgl (%ebx), %eax\n\t"
"movl %eax, %edx\n\t"
"jmp again\n\t");
}
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