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

[Harald Freudenberger]

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.
>
>> + */
>> +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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