On Sat, 2005-01-01 at 13:34 +1100, Nick Piggin wrote:
> Justin Pryzby wrote:
> > Hi all, I have more 2.5isms for the list.  ./fs/binfmt_elf.c:
> > 
> >   #ifdef CONFIG_X86_HT
> >                   /*
> >                    * In some cases (e.g. Hyper-Threading), we want to avoid L1
> >                    * evictions by the processes running on the same package. One
> >                    * thing we can do is to shuffle the initial stack for them.
> >                    *
> >                    * The conditionals here are unneeded, but kept in to make the
> >                    * code behaviour the same as pre change unless we have
> >                    * hyperthreaded processors. This should be cleaned up
> >                    * before 2.6
> >                    */
> > 
> >                   if (smp_num_siblings > 1)
> >                           STACK_ALLOC(p, ((current->pid % 64) << 7));
> >   #endif
> > 
> 
> Can we just kill it? Or do it unconditionally? Or maybe better yet, wrap
> it properly in arch code?

something like this perhaps?
http://www.kernel.org/pub/linux/kernel/people/arjan/execshield/00-
randomize-A0

although that randomizes more than just the stack pointer; the idea for
just the stackpointer should be clear