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

Tony Krowiak
2018-08-09T16:06:56Z

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@linux.vnet.ibm.com> wrote:
>>
>>> From: Harald Freudenberger <freude@de.ibm.com>
>>>
>>> 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@de.ibm.com>
>>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> 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;
>>> +}
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-s390" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>