On Mon, Jul 10, 2017 at 08:41:30AM +0530, Anshuman Khandual wrote:
> On 07/06/2017 02:52 AM, Ram Pai wrote:
> > get_pte_pkey() helper returns the pkey associated with
> > a address corresponding to a given mm_struct.
> >
> > Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
> > ---
> > arch/powerpc/include/asm/book3s/64/mmu-hash.h | 5 ++++
> > arch/powerpc/mm/hash_utils_64.c | 28 +++++++++++++++++++++++++
> > 2 files changed, 33 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> > index f7a6ed3..369f9ff 100644
> > --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> > +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> > @@ -450,6 +450,11 @@ extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap,
> > int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
> > pte_t *ptep, unsigned long trap, unsigned long flags,
> > int ssize, unsigned int shift, unsigned int mmu_psize);
> > +
> > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
> > +u16 get_pte_pkey(struct mm_struct *mm, unsigned long address);
> > +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
> > +
> > #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> > extern int __hash_page_thp(unsigned long ea, unsigned long access,
> > unsigned long vsid, pmd_t *pmdp, unsigned long trap,
> > diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> > index 1e74529..591990c 100644
> > --- a/arch/powerpc/mm/hash_utils_64.c
> > +++ b/arch/powerpc/mm/hash_utils_64.c
> > @@ -1573,6 +1573,34 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
> > local_irq_restore(flags);
> > }
> >
> > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
> > +/*
> > + * return the protection key associated with the given address
> > + * and the mm_struct.
> > + */
> > +u16 get_pte_pkey(struct mm_struct *mm, unsigned long address)
> > +{
> > + pte_t *ptep;
> > + u16 pkey = 0;
> > + unsigned long flags;
> > +
> > + if (REGION_ID(address) == VMALLOC_REGION_ID)
> > + mm = &init_mm;
>
> IIUC, protection keys are only applicable for user space. This
> function is getting used to populate siginfo structure. Then how
> can we ever request this for any address in VMALLOC region.
make sense. this check is not needed.
>
> > +
> > + if (!mm || !mm->pgd)
> > + return 0;
>
> Is this really required at this stage ?
its a sanity check to gaurd against bad inputs. See a problem?
RP
--
Ram Pai
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