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authorHarald Freudenberger <freude@linux.ibm.com>2021-06-30 16:10:56 +0200
committerVasily Gorbik <gor@linux.ibm.com>2021-07-08 15:37:27 +0200
commit1f0d22defd59f603d63ba51483eeb8d72726ce8b (patch)
tree2d5596036c3cdb260d56cc3b7902490f72ba25a2
parentbd39654a2282c1a51c044575a6bc00d641d5dfd1 (diff)
s390/ap: Rework ap_dqap to deal with messages greater than recv buffer
Rework of the ap_dqap() inline function with the dqap inline assembler invocation and the caller code in ap_queue.c to be able to handle replies which exceed the receive buffer size. ap_dqap() now provides two additional parameters to handle together with the caller the case where a reply in the firmware queue entry exceeds the given message buffer size. It depends on the caller how to exactly handle this. The behavior implemented now by ap_sm_recv() in ap_queue.c is to simple purge this entry from the firmware queue and let the caller 'receive' a -EMSGSIZE for the request without delivering any reply data - not even a truncated reply message. However, the reworked ap_dqap() could now get invoked in a way that the message is received in multiple parts and the caller assembles the parts into one reply message. Signed-off-by: Harald Freudenberger <freude@linux.ibm.com> Suggested-by: Juergen Christ <jchrist@linux.ibm.com> Reviewed-by: Juergen Christ <jchrist@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
-rw-r--r--arch/s390/include/asm/ap.h48
-rw-r--r--drivers/s390/crypto/ap_queue.c28
2 files changed, 65 insertions, 11 deletions
diff --git a/arch/s390/include/asm/ap.h b/arch/s390/include/asm/ap.h
index 837d1699b109..5e77a81ab36a 100644
--- a/arch/s390/include/asm/ap.h
+++ b/arch/s390/include/asm/ap.h
@@ -325,6 +325,8 @@ static inline struct ap_queue_status ap_nqap(ap_qid_t qid,
* @psmid: Pointer to program supplied message identifier
* @msg: The message text
* @length: The message length
+ * @reslength: Resitual length on return
+ * @resgr0: input: gr0 value (only used if != 0), output: resitual gr0 content
*
* Returns AP queue status structure.
* Condition code 1 on DQAP means the receive has taken place
@@ -336,12 +338,25 @@ static inline struct ap_queue_status ap_nqap(ap_qid_t qid,
* Note that gpr2 is used by the DQAP instruction to keep track of
* any 'residual' length, in case the instruction gets interrupted.
* Hence it gets zeroed before the instruction.
+ * If the message does not fit into the buffer, this function will
+ * return with a truncated message and the reply in the firmware queue
+ * is not removed. This is indicated to the caller with an
+ * ap_queue_status response_code value of all bits on (0xFF) and (if
+ * the reslength ptr is given) the remaining length is stored in
+ * *reslength and (if the resgr0 ptr is given) the updated gr0 value
+ * for further processing of this msg entry is stored in *resgr0. The
+ * caller needs to detect this situation and should invoke ap_dqap
+ * with a valid resgr0 ptr and a value in there != 0 to indicate that
+ * *resgr0 is to be used instead of qid to further process this entry.
*/
static inline struct ap_queue_status ap_dqap(ap_qid_t qid,
unsigned long long *psmid,
- void *msg, size_t length)
+ void *msg, size_t length,
+ size_t *reslength,
+ unsigned long *resgr0)
{
- register unsigned long reg0 asm("0") = qid | 0x80000000UL;
+ register unsigned long reg0 asm("0") =
+ resgr0 && *resgr0 ? *resgr0 : qid | 0x80000000UL;
register struct ap_queue_status reg1 asm ("1");
register unsigned long reg2 asm("2") = 0UL;
register unsigned long reg4 asm("4") = (unsigned long) msg;
@@ -349,14 +364,33 @@ static inline struct ap_queue_status ap_dqap(ap_qid_t qid,
register unsigned long reg6 asm("6") = 0UL;
register unsigned long reg7 asm("7") = 0UL;
-
asm volatile(
- "0: .long 0xb2ae0064\n" /* DQAP */
- " brc 6,0b\n"
+ "0: ltgr %[bl],%[bl]\n" /* if avail. buf len is 0 then */
+ " jz 2f\n" /* go out of this asm block */
+ "1: .long 0xb2ae0064\n" /* DQAP */
+ " brc 6,0b\n" /* if partially do again */
+ "2:\n"
: "+d" (reg0), "=d" (reg1), "+d" (reg2),
- "+d" (reg4), "+d" (reg5), "+d" (reg6), "+d" (reg7)
+ "+d" (reg4), [bl] "+d" (reg5), "+d" (reg6), "+d" (reg7)
: : "cc", "memory");
- *psmid = (((unsigned long long) reg6) << 32) + reg7;
+
+ if (reslength)
+ *reslength = reg2;
+ if (reg2 != 0 && reg5 == 0) {
+ /*
+ * Partially complete, status in gr1 is not set.
+ * Signal the caller that this dqap is only partially received
+ * with a special status response code 0xFF and *resgr0 updated
+ */
+ reg1.response_code = 0xFF;
+ if (resgr0)
+ *resgr0 = reg0;
+ } else {
+ *psmid = (((unsigned long long) reg6) << 32) + reg7;
+ if (resgr0)
+ *resgr0 = 0;
+ }
+
return reg1;
}
diff --git a/drivers/s390/crypto/ap_queue.c b/drivers/s390/crypto/ap_queue.c
index c5e0fe0286e5..669f96fddad6 100644
--- a/drivers/s390/crypto/ap_queue.c
+++ b/drivers/s390/crypto/ap_queue.c
@@ -101,7 +101,7 @@ int ap_recv(ap_qid_t qid, unsigned long long *psmid, void *msg, size_t length)
if (msg == NULL)
return -EINVAL;
- status = ap_dqap(qid, psmid, msg, length);
+ status = ap_dqap(qid, psmid, msg, length, NULL, NULL);
switch (status.response_code) {
case AP_RESPONSE_NORMAL:
return 0;
@@ -136,9 +136,24 @@ static struct ap_queue_status ap_sm_recv(struct ap_queue *aq)
struct ap_queue_status status;
struct ap_message *ap_msg;
bool found = false;
+ size_t reslen;
+ unsigned long resgr0 = 0;
+ int parts = 0;
+
+ /*
+ * DQAP loop until response code and resgr0 indicate that
+ * the msg is totally received. As we use the very same buffer
+ * the msg is overwritten with each invocation. That's intended
+ * and the receiver of the msg is informed with a msg rc code
+ * of EMSGSIZE in such a case.
+ */
+ do {
+ status = ap_dqap(aq->qid, &aq->reply->psmid,
+ aq->reply->msg, aq->reply->bufsize,
+ &reslen, &resgr0);
+ parts++;
+ } while (status.response_code == 0xFF && resgr0 != 0);
- status = ap_dqap(aq->qid, &aq->reply->psmid,
- aq->reply->msg, aq->reply->bufsize);
switch (status.response_code) {
case AP_RESPONSE_NORMAL:
aq->queue_count = max_t(int, 0, aq->queue_count - 1);
@@ -150,7 +165,12 @@ static struct ap_queue_status ap_sm_recv(struct ap_queue *aq)
continue;
list_del_init(&ap_msg->list);
aq->pendingq_count--;
- ap_msg->receive(aq, ap_msg, aq->reply);
+ if (parts > 1) {
+ ap_msg->rc = -EMSGSIZE;
+ ap_msg->receive(aq, ap_msg, NULL);
+ } else {
+ ap_msg->receive(aq, ap_msg, aq->reply);
+ }
found = true;
break;
}