Re: [PATCH 04/25] powerpc: helper function to read,write AMR,IAMR,UAMOR registers

[Ram Pai <linuxram@us.ibm.com>]

On Wed, Oct 18, 2017 at 02:17:35PM +1100, Balbir Singh wrote:
> On Fri,  8 Sep 2017 15:44:52 -0700
> Ram Pai <linuxram@us.ibm.com> wrote:
> 
> > Implements helper functions to read and write the key related
> > registers; AMR, IAMR, UAMOR.
> > 
> > AMR register tracks the read,write permission of a key
> > IAMR register tracks the execute permission of a key
> > UAMOR register enables and disables a key
> > 
> > Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> > ---
> >  arch/powerpc/include/asm/book3s/64/pgtable.h |   31 ++++++++++++++++++++++++++
> >  1 files changed, 31 insertions(+), 0 deletions(-)
> > 
> > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> > index b9aff51..73ed52c 100644
> > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> > @@ -438,6 +438,37 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
> >  		pte_update(mm, addr, ptep, 0, _PAGE_PRIVILEGED, 1);
> >  }
> >  
> > +#include <asm/reg.h>
> > +static inline u64 read_amr(void)
> > +{
> > +	return mfspr(SPRN_AMR);
> > +}
> > +static inline void write_amr(u64 value)
> > +{
> > +	mtspr(SPRN_AMR, value);
> > +}
> 
> Do we care to validate values or is that in
> the caller


No. Caller is expected to validate the values.

> 
> > +extern bool pkey_execute_disable_support;
> > +static inline u64 read_iamr(void)
> > +{
> > +	if (pkey_execute_disable_support)
> > +		return mfspr(SPRN_IAMR);
> > +	else
> > +		return 0x0UL;
> > +}
> > +static inline void write_iamr(u64 value)
> > +{
> > +	if (pkey_execute_disable_support)
> > +		mtspr(SPRN_IAMR, value);
> > +}
> > +static inline u64 read_uamor(void)
> > +{
> > +	return mfspr(SPRN_UAMOR);
> > +}
> > +static inline void write_uamor(u64 value)
> > +{
> > +	mtspr(SPRN_UAMOR, value);
> > +}
> > +
> >  #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
> >  static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
> >  				       unsigned long addr, pte_t *ptep)
> 
> Looks reasonable otherwise

Thanks!
RP


> Acked-by: Balbir Singh <bsingharora@gmail.com>

-- 
Ram Pai