Re: [PATCH] LoongArch: add p?d_leaf() definitions

[Hongchen Zhang]

Hi David,

On 2023/9/6 pm 3:42, David Hildenbrand wrote:
> On 05.09.23 08:49, Hongchen Zhang wrote:
> > When I do LTP test, LTP test case ksm06 caused panic at
> >     break_ksm_pmd_entry
> >       -> pmd_leaf (Huge page table but False)
> >       -> pte_present (panic)
>
> Probably there are other problematic bits without that can trigger that? 
> I suspect walk_page_range*() callers might be affected,
I rechecked the code and found that other architectures that support
THP have defined pmd_leaf.
So there is not problem on other architectures.
> > The reason is pmd_leaf is not defined, So like
> > commit 501b81046701 ("mips: mm: add p?d_leaf() definitions")
> > add p?d_leaf() definition for LoongArch.
>
> We most certainly want to cc stable, no?
OK, let me cc stable in V2.
> Can we come up with a Fixes: tag? Probably when we added THP support to 
> loongarch.
OK, let me add Fixes: in commit message in V2.
> > Signed-off-by: Hongchen Zhang <zhanghongchen@xxxxxxxxxxx>
> > ---
> >   arch/loongarch/include/asm/pgtable.h | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/arch/loongarch/include/asm/pgtable.h 
> > b/arch/loongarch/include/asm/pgtable.h
> > index 370c6568ceb8..ea54653b7aab 100644
> > --- a/arch/loongarch/include/asm/pgtable.h
> > +++ b/arch/loongarch/include/asm/pgtable.h
> > @@ -243,6 +243,9 @@ static inline void pmd_clear(pmd_t *pmdp)
> >   #define pmd_phys(pmd)        PHYSADDR(pmd_val(pmd))
> > +#define pmd_leaf(pmd)        ((pmd_val(pmd) & _PAGE_HUGE) != 0)
> > +#define pud_leaf(pud)        ((pud_val(pud) & _PAGE_HUGE) != 0)
> > +
> >   #ifndef CONFIG_TRANSPARENT_HUGEPAGE
> >   #define pmd_page(pmd)        (pfn_to_page(pmd_phys(pmd) >> PAGE_SHIFT))
> >   #endif /* CONFIG_TRANSPARENT_HUGEPAGE  */
>
> Acked-by: David Hildenbrand <david@xxxxxxxxxx>


--
Best Regards
Hongchen Zhang