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

From: Tony Krowiak
Date: Thu Aug 09 2018 - 11:18:21 EST


On 08/09/2018 05:06 AM, 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.)

That's rather ironic given I was told in an internal review that I should
not sign off on patches I did not write.


---
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?

+ */
+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;
+}