On Wed, Oct 18, 2017 at 02:24:03PM +1100, Balbir Singh wrote:
> On Fri, 8 Sep 2017 15:44:53 -0700
> Ram Pai <linux...@us.ibm.com> wrote:
>
> > Introduce helper functions that can initialize the bits in the AMR,
> > IAMR and UAMOR register; the bits that correspond to the given pkey.
> >
> > Signed-off-by: Ram Pai <linux...@us.ibm.com>
> > ---
> > arch/powerpc/include/asm/pkeys.h | 1 +
> > arch/powerpc/mm/pkeys.c | 46
> > ++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 47 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/pkeys.h
> > b/arch/powerpc/include/asm/pkeys.h
> > index 133f8c4..5a83ed7 100644
> > --- a/arch/powerpc/include/asm/pkeys.h
> > +++ b/arch/powerpc/include/asm/pkeys.h
> > @@ -26,6 +26,7 @@
> > #define arch_max_pkey() pkeys_total
> > #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
> > VM_PKEY_BIT3 | VM_PKEY_BIT4)
> > +#define AMR_BITS_PER_PKEY 2
> >
> > #define pkey_alloc_mask(pkey) (0x1 << pkey)
> >
> > diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
> > index ebc9e84..178aa33 100644
> > --- a/arch/powerpc/mm/pkeys.c
> > +++ b/arch/powerpc/mm/pkeys.c
> > @@ -59,3 +59,49 @@ void __init pkey_initialize(void)
> > for (i = 2; i < (pkeys_total - os_reserved); i++)
> > initial_allocation_mask &= ~(0x1<<i);
> > }
> > +
> > +#define PKEY_REG_BITS (sizeof(u64)*8)
> > +#define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey+1) * AMR_BITS_PER_PKEY))
> > +
> > +static inline void init_amr(int pkey, u8 init_bits)
> > +{
> > + u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey));
> > + u64 old_amr = read_amr() & ~((u64)(0x3ul) << pkeyshift(pkey));
> > +
>
> Do we need to check for reserved keys or that is at a layer above?
These routines blindly trust the caller. The assumption is the
system calls which are the gate-keepers for the keys validate
the keys before calling any lower level functions.
>
> > + write_amr(old_amr | new_amr_bits);
> > +}
> > +
> > +static inline void init_iamr(int pkey, u8 init_bits)
> > +{
> > + u64 new_iamr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey));
> > + u64 old_iamr = read_iamr() & ~((u64)(0x3ul) << pkeyshift(pkey));
> > +
> > + write_iamr(old_iamr | new_iamr_bits);
>
> Do we need to check for reserved keys here?
>
ditto..
> > +}
> > +
> > +static void pkey_status_change(int pkey, bool enable)
> > +{
> > + u64 old_uamor;
> > +
> > + /* reset the AMR and IAMR bits for this key */
> > + init_amr(pkey, 0x0);
> > + init_iamr(pkey, 0x0);
> > +
> > + /* enable/disable key */
> > + old_uamor = read_uamor();
> > + if (enable)
> > + old_uamor |= (0x3ul << pkeyshift(pkey));
> > + else
> > + old_uamor &= ~(0x3ul << pkeyshift(pkey));
> > + write_uamor(old_uamor);
> > +}
> > +
> > +void __arch_activate_pkey(int pkey)
> > +{
> > + pkey_status_change(pkey, true);
> > +}
> > +
> > +void __arch_deactivate_pkey(int pkey)
> > +{
> > + pkey_status_change(pkey, false);
> > +}
>
>
> Balbir Singh.
--
Ram Pai
