Re: [PATCH v3 1/7] x86/sgx: Provide indication of life-cycle of EPC pages

From: Jarkko Sakkinen
Date: Thu Jul 29 2021 - 20:34:43 EST


On Wed, Jul 28, 2021 at 10:57:07PM +0000, Luck, Tony wrote:
> > Wouldn't it be safer to do something like:
> >
> > page->owner = owner ? owner : (void *)-1;
> >
> > -1 is non-NULL, but also invalid, which makes it harder for us to poke
> > ourselves in the eye.
>
> Does Linux have some #define INVALID_POINTER thing that
> provides a guaranteed bad (e.g. non-canonical) value?
>
> (void *)-1 seems hacky.
>
> -Tony

MAP_FAILED?

/Jarkko