Re: [PATCH v8 04/22] s390/zcrypt: Integrate ap_asm.h into include/asm/ap.h.

[Tony Krowiak]

On 08/09/2018 05:17 AM, Harald Freudenberger wrote:
> On 09.08.2018 11:06, Cornelia Huck wrote:
> > On Wed,  8 Aug 2018 10:44:14 -0400
> > Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > > From: Harald Freudenberger <freude@xxxxxxxxxx>
> > >
> > > Move all the inline functions from the ap bus header
> > > file ap_asm.h into the in-kernel api header file
> > > arch/s390/include/asm/ap.h so that KVM can make use
> > > of all the low level AP functions.
> > >
> > > Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxx>
> > > Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> > You should add your own s-o-b if you are sending on patches written by
> > others (even if it does not matter in the end, when they are merged
> > through a different path anyway.)
> >
> > > ---
> > >   arch/s390/include/asm/ap.h     |  284 ++++++++++++++++++++++++++++++++++++----
> > >   drivers/s390/crypto/ap_asm.h   |  261 ------------------------------------
> > >   drivers/s390/crypto/ap_bus.c   |   21 +---
> > >   drivers/s390/crypto/ap_bus.h   |    1 +
> > >   drivers/s390/crypto/ap_card.c  |    1 -
> > >   drivers/s390/crypto/ap_queue.c |    1 -
> > >   6 files changed, 259 insertions(+), 310 deletions(-)
> > >   delete mode 100644 drivers/s390/crypto/ap_asm.h
> > >
> > > diff --git a/arch/s390/include/asm/ap.h b/arch/s390/include/asm/ap.h
> > > index c1bedb4..046e044 100644
> > > --- a/arch/s390/include/asm/ap.h
> > > +++ b/arch/s390/include/asm/ap.h
> > > @@ -47,6 +47,50 @@ struct ap_queue_status {
> > >   };
> > >   
> > >   /**
> > > + * ap_intructions_available() - Test if AP instructions are available.
> > > + *
> > > + * Returns 0 if the AP instructions are installed.
> > Stumbled over this when I was looking at the usage in patch 7: if I see
> > a function called '_available' return 0, I'd assume that whatever the
> > function tests for is *not* available.
> >
> > Rather call this function ap_instructions_check_availability() (and
> > keep the return code convention), or switch this to return 0 if not
> > available and !0 if available?
> Good catch, Cony you are right. I'll fix this to return 1 if AP instructions
> are available and 0 if not. However, this patch will come via Martin's pipe
> to the Linus Torwald kernel sources.

Is your intent to simply indicate whether the AP instructions are 
available or
not; or is the intention to indicate whether the AP instructions are 
available
and if not, they why? In the former, then I agree that a boolean should be
returned; however, if the case is the latter, then what you have is fine but
maybe the function name should be changed as Connie suggests.

> > > + */
> > > +static inline int ap_instructions_available(void)
> > > +{
> > > +	register unsigned long reg0 asm ("0") = AP_MKQID(0, 0);
> > > +	register unsigned long reg1 asm ("1") = -ENODEV;
> > > +	register unsigned long reg2 asm ("2");
> > > +
> > > +	asm volatile(
> > > +		"   .long 0xb2af0000\n"		/* PQAP(TAPQ) */
> > > +		"0: la    %0,0\n"
> > > +		"1:\n"
> > > +		EX_TABLE(0b, 1b)
> > > +		: "+d" (reg1), "=d" (reg2)
> > > +		: "d" (reg0)
> > > +		: "cc");
> > > +	return reg1;
> > > +}
> > --
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