Re: [PATCH -next 3/4] arm64: mm: add support for page table check

[Tong Tiangen]

在 2022/3/22 0:40, Catalin Marinas 写道:
> On Mon, Mar 21, 2022 at 02:15:36PM +0800, Tong Tiangen wrote:
> > Considering all your suggestions, The final logic should be:
> >
> > +#define pte_user(pte)          (!!(pte_val(pte) & PTE_USER))
> >
> > +#define pmd_user(pmd)		pte_user(pmd_pte(pmd))
> > +#define pmd_user_exec(pmd)	pte_user_exec(pmd_pte(pmd))
> >
> > +#define pud_user(pud)          pte_user(pud_pte(pud))
> >
> > +static inline bool pte_user_accessible_page(pte_t pte)
> > +{
> > +	return pte_present(pte) && (pte_user(pte)|| pte_user_exec(pte));
> > +}
>
> This is fine.
>
> > +static inline bool pmd_user_accessible_page(pmd_t pmd)
> > +{
> > +	return pmd_present(pmd) && (pmd_user(pmd)|| pmd_user_exec(pmd));
> > +}
>
> That's fine as well assuming that the function is only called on the
> set_pmd_at() path where we know that the pmd would be a block mapping
> (huge page). I think that's the case from a quick look at the current
> x86 implementation.

Yeah, PTC only check pmd block mapping(huge page) and pud is similar.
These code logic will be included in V2.

Thanks.

> > +static inline bool pud_user_accessible_page(pud_t pud)
> > +{
> > +	return pud_present(pud) && pud_user(pud);
> > +}
>
> Same here.