lkml.org 
[lkml]   [2003]   [Jul]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: TSCs are a no-no on i386
Alan Cox wrote:
> > > And if the byte you are looking at was patched by another thread you've
> > > blown it. Your emulation can only be so good 8) People do stuff like
> > > patching instructions under software decode as a robustness check - its
> > > normally pretty amusing
> >
> > On a uniprocessor 386, this is not a problem. Just disable preemption
> > in the kernel decoder.
>
> Wrong again. Thats a common myth but you see I can put the instruction on a page
> so that its executed from a page I just did a read() into in another process. If
> I'm really bored I'll use O_DIRECT but thats mostly for makign life really bad
> for non cache coherent setups 8)

I wouldn't be surprised if even real CPUs mis-decode when there's a
concurrent DMA into the area they are reading instructions from! :)

-- Jamie
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:47    [W:0.086 / U:0.844 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site