Messages in this thread | | | Date | Fri, 9 Mar 2018 12:09:17 -0800 | From | Ram Pai <> | Subject | Re: [PATCH] x86, powerpc : pkey-mprotect must allow pkey-0 |
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On Fri, Mar 09, 2018 at 09:43:32AM +0100, Ingo Molnar wrote: > > * Ram Pai <linuxram@us.ibm.com> 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@intel.com> > > cc: Michael Ellermen <mpe@ellerman.id.au> > > cc: Ingo Molnar <mingo@kernel.org> > > Signed-off-by: Ram Pai <linuxram@us.ibm.com> > > --- > > 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
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