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SubjectRe: [PATCH RFC V3 2/9] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support
On Fri, Oct 16, 2020 at 12:57:43PM +0200, Peter Zijlstra wrote:
> On Fri, Oct 09, 2020 at 12:42:51PM -0700, ira.weiny@intel.com wrote:
> > From: Fenghua Yu <fenghua.yu@intel.com>
> >
> > Define a helper, update_pkey_val(), which will be used to support both
> > Protection Key User (PKU) and the new Protection Key for Supervisor
> > (PKS) in subsequent patches.
> >
> > Co-developed-by: Ira Weiny <ira.weiny@intel.com>
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> > ---
> > arch/x86/include/asm/pkeys.h | 2 ++
> > arch/x86/kernel/fpu/xstate.c | 22 ++++------------------
> > arch/x86/mm/pkeys.c | 21 +++++++++++++++++++++
> > 3 files changed, 27 insertions(+), 18 deletions(-)
>
> This is not from Fenghua.
>
> https://lkml.kernel.org/r/20200717085442.GX10769@hirez.programming.kicks-ass.net
>
> This is your patch based on the code I wrote.

Ok, I apologize. Yes the code below was all yours.

Is it ok to add?

Co-developed-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>

?

Thanks,
Ira

>
> > diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
> > index f5efb4007e74..3cf8f775f36d 100644
> > --- a/arch/x86/mm/pkeys.c
> > +++ b/arch/x86/mm/pkeys.c
> > @@ -208,3 +208,24 @@ static __init int setup_init_pkru(char *opt)
> > return 1;
> > }
> > __setup("init_pkru=", setup_init_pkru);
> > +
> > +/*
> > + * Update the pk_reg value and return it.
> > + *
> > + * Kernel users use the same flags as user space:
> > + * PKEY_DISABLE_ACCESS
> > + * PKEY_DISABLE_WRITE
> > + */
> > +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
> > +{
> > + int pkey_shift = pkey * PKR_BITS_PER_PKEY;
> > +
> > + pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift);
> > +
> > + if (flags & PKEY_DISABLE_ACCESS)
> > + pk_reg |= PKR_AD_BIT << pkey_shift;
> > + if (flags & PKEY_DISABLE_WRITE)
> > + pk_reg |= PKR_WD_BIT << pkey_shift;
> > +
> > + return pk_reg;
> > +}
> > --
> > 2.28.0.rc0.12.gb6a658bd00c9
> >

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