On Sat, Oct 4, 2014 at 1:23 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Fri, Oct 03, 2014 at 08:17:14PM -0700, Leonid Yegoshin wrote:
>> The following series implements an executable stack protection in MIPS.
>>
>> It sets up a per-thread 'VDSO' page and appropriate TLB support.
>
> So traditionally we've always avoided per-thread pages like that. What
> makes it worth it on MIPS?
Nothing makes it worth it on MIPS.
It may be easy to implement when you have all software-fill of TLB's,
but it's a mistake even then - because it means that you'll never be
able to do hardware TLB walkers.
And MIPS *does* have hardware TLB walkers, even if they are not
necessarily available everywhere.
So this is a horrible idea. Don't do it. Page tables need to be
per-process, not per thread, so that page tables can be shared.
Linus
