[PATCH 02/25] powerpc: define an additional vma bit for protection keys.

[Ram Pai]

On Mon, Oct 23, 2017 at 02:58:55PM +0530, Aneesh Kumar K.V wrote:
> "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com> writes:
> 
> > Ram Pai <linuxram at us.ibm.com> writes:
> >
> >> powerpc needs an additional vma bit to support 32 keys.
> >> Till the additional vma bit lands in include/linux/mm.h
> >> we have to define  it  in powerpc specific header file.
> >> This is  needed to get pkeys working on power.
> >>
> >> Signed-off-by: Ram Pai <linuxram at us.ibm.com>
> >> ---
> >>  arch/powerpc/include/asm/pkeys.h |   18 ++++++++++++++++++
> >>  1 files changed, 18 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
> >> index c02305a..44e01a2 100644
> >> --- a/arch/powerpc/include/asm/pkeys.h
> >> +++ b/arch/powerpc/include/asm/pkeys.h
> >> @@ -3,6 +3,24 @@
> >>
> >>  extern bool pkey_inited;
> >>  extern bool pkey_execute_disable_support;
> >> +
> >> +/*
> >> + * powerpc needs an additional vma bit to support 32 keys.
> >> + * Till the additional vma bit lands in include/linux/mm.h
> >> + * we have to carry the hunk below. This is  needed to get
> >> + * pkeys working on power. -- Ram
> >> + */
> >> +#ifndef VM_HIGH_ARCH_BIT_4
> >> +#define VM_HIGH_ARCH_BIT_4	36
> >> +#define VM_HIGH_ARCH_4	BIT(VM_HIGH_ARCH_BIT_4)
> >> +#define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
> >> +#define VM_PKEY_BIT0	VM_HIGH_ARCH_0
> >> +#define VM_PKEY_BIT1	VM_HIGH_ARCH_1
> >> +#define VM_PKEY_BIT2	VM_HIGH_ARCH_2
> >> +#define VM_PKEY_BIT3	VM_HIGH_ARCH_3
> >> +#define VM_PKEY_BIT4	VM_HIGH_ARCH_4
> >> +#endif
> >> +
> >>  #define ARCH_VM_PKEY_FLAGS 0
> >
> > Do we want them in pkeys.h ? Even if they are arch specific for the
> > existing ones we have them in include/linux/mm.h. IIUC, vmflags details
> > are always in mm.h? This will be the first exception to that?
> 
> 
> Also can we move that 
> 
> #if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS)
> # define VM_PKEY_SHIFT	VM_HIGH_ARCH_BIT_0
> # define VM_PKEY_BIT0	VM_HIGH_ARCH_0	/* A protection key is a 4-bit value */
> # define VM_PKEY_BIT1	VM_HIGH_ARCH_1
> # define VM_PKEY_BIT2	VM_HIGH_ARCH_2
> # define VM_PKEY_BIT3	VM_HIGH_ARCH_3
> #endif
> 
> to
> 
> #if defined (CONFIG_ARCH_HAS_PKEYS)
> # define VM_PKEY_SHIFT	VM_HIGH_ARCH_BIT_0
> # define VM_PKEY_BIT0	VM_HIGH_ARCH_0	/* A protection key is a 4-bit value */
> # define VM_PKEY_BIT1	VM_HIGH_ARCH_1
> # define VM_PKEY_BIT2	VM_HIGH_ARCH_2
> # define VM_PKEY_BIT3	VM_HIGH_ARCH_3
> #endif
> 
> 
> And then later update the generic to handle PKEY_BIT4?


Yes. The above changes have been implemented in a patch sent to the mm
mailing list as well as to lkml.

https://lkml.org/lkml/2017/9/15/504

RP