Commit 1f0d22de authored by Harald Freudenberger's avatar Harald Freudenberger Committed by Vasily Gorbik
Browse files

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: default avatarHarald Freudenberger <freude@linux.ibm.com>
Suggested-by: default avatarJuergen Christ <jchrist@linux.ibm.com>
Reviewed-by: default avatarJuergen Christ <jchrist@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent bd39654a

arch/s390/include/asm/ap.h

+41 −7
Original line number Diff line number Diff line
@@ -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");



	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;

}

drivers/s390/crypto/ap_queue.c

+24 −4
Original line number Diff line number Diff line
@@ -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);

				 aq->reply->msg, aq->reply->bufsize,

				 &reslen, &resgr0);

		parts++;

	} while (status.response_code == 0xFF && resgr0 != 0);



	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--;

			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;

		}