Re: [PATCH] x86_64: Disabling read-implies-exec when the stack is executable

[Andi Kleen]

> However, I would tend to agree: RIE should only be needed on 32-bit
> since 64-bit started its life knowing about no-exec permissions.

NX was not in the original AMD K8 chips.  Was only added some time later.

> set_personality_64bit()'s (which is confusingly just an initializer
> and not called during the personality() syscall) comment about this
> makes no sense to me:
> 
>         /* TBD: overwrites user setup. Should have two bits.
>            But 64bit processes have always behaved this way,
>            so it's not too bad. The main problem is just that
>            32bit childs are affected again. */
>         current->personality &= ~READ_IMPLIES_EXEC;

What does not make sense?

-Andi