On Fri, Mar 09, 2018 at 09:43:32AM +0100, Ingo Molnar wrote:
>
> * Ram Pai <linuxram@xxxxxxxxxx> wrote:
>
> > Once an address range is associated with an allocated pkey, it cannot be
> > reverted back to key-0. There is no valid reason for the above behavior. On
> > the contrary applications need the ability to do so.
> >
> > The patch relaxes the restriction.
> >
> > Tested on powerpc and x86_64.
> >
> > cc: Dave Hansen <dave.hansen@xxxxxxxxx>
> > cc: Michael Ellermen <mpe@xxxxxxxxxxxxxx>
> > cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
> > ---
> > arch/powerpc/include/asm/pkeys.h | 19 ++++++++++++++-----
> > arch/x86/include/asm/pkeys.h | 5 +++--
> > 2 files changed, 17 insertions(+), 7 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
> > index 0409c80..3e8abe4 100644
> > --- a/arch/powerpc/include/asm/pkeys.h
> > +++ b/arch/powerpc/include/asm/pkeys.h
> > @@ -101,10 +101,18 @@ static inline u16 pte_to_pkey_bits(u64 pteflags)
> >
> > static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
> > {
> > - /* A reserved key is never considered as 'explicitly allocated' */
> > - return ((pkey < arch_max_pkey()) &&
> > - !__mm_pkey_is_reserved(pkey) &&
> > - __mm_pkey_is_allocated(mm, pkey));
> > + /* pkey 0 is allocated by default. */
> > + if (!pkey)
> > + return true;
> > +
> > + if (pkey < 0 || pkey >= arch_max_pkey())
> > + return false;
> > +
> > + /* reserved keys are never allocated. */
> > + if (__mm_pkey_is_reserved(pkey))
> > + return false;
>
> Please capitalize in comments consistently, i.e.:
ok.
>
> /* Reserved keys are never allocated: */
>
> > +
> > + return(__mm_pkey_is_allocated(mm, pkey));
>
> 'return' is not a function.
right. will fix.
Thanks,
RP
