[S390] qdio: use proper QEBSM operand for SIGA-R and SIGA-S

If QIOASSIST is enabled for a qdio device the SIGA instruction requires
a modified function code. This function code modifier was missing for
SIGA-R and SIGA-S which can lead to a kernel panic caused by an
operand exception.

Cc: stable@kernel.org
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 34 insertions, 15 deletions

diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h
index 40ca0b9241e5..0a42da4beafa 100644
--- a/drivers/s390/cio/qdio.h
+++ b/drivers/s390/cio/qdio.h
@@ -91,6 +91,12 @@ enum qdio_irq_states {
 #define AC1_SC_QEBSM_AVAILABLE          0x02    /* available for subchannel */
 #define AC1_SC_QEBSM_ENABLED            0x01    /* enabled for subchannel */
 
+/* SIGA flags */
+#define QDIO_SIGA_WRITE         0x00
+#define QDIO_SIGA_READ          0x01
+#define QDIO_SIGA_SYNC          0x02
+#define QDIO_SIGA_QEBSM_FLAG    0x80
+
 #ifdef CONFIG_64BIT
 static inline int do_sqbs(u64 token, unsigned char state, int queue,
                           int *start, int *count)
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index af86875bede4..99823477d57e 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -30,11 +30,12 @@ MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>,"\
 MODULE_DESCRIPTION("QDIO base support");
 MODULE_LICENSE("GPL");
 
-static inline int do_siga_sync(struct subchannel_id schid,
-                               unsigned int out_mask, unsigned int in_mask)
+static inline int do_siga_sync(unsigned long schid,
+                               unsigned int out_mask, unsigned int in_mask,
+                               unsigned int fc)
 {
-        register unsigned long __fc asm ("0") = 2;
-        register struct subchannel_id __schid asm ("1") = schid;
+        register unsigned long __fc asm ("0") = fc;
+        register unsigned long __schid asm ("1") = schid;
         register unsigned long out asm ("2") = out_mask;
         register unsigned long in asm ("3") = in_mask;
         int cc;
@@ -48,10 +49,11 @@ static inline int do_siga_sync(struct subchannel_id schid,
         return cc;
 }
 
-static inline int do_siga_input(struct subchannel_id schid, unsigned int mask)
+static inline int do_siga_input(unsigned long schid, unsigned int mask,
+                                unsigned int fc)
 {
-        register unsigned long __fc asm ("0") = 1;
-        register struct subchannel_id __schid asm ("1") = schid;
+        register unsigned long __fc asm ("0") = fc;
+        register unsigned long __schid asm ("1") = schid;
         register unsigned long __mask asm ("2") = mask;
         int cc;
 
@@ -280,6 +282,8 @@ void qdio_init_buf_states(struct qdio_irq *irq_ptr)
 static inline int qdio_siga_sync(struct qdio_q *q, unsigned int output,
                           unsigned int input)
 {
+        unsigned long schid = *((u32 *) &q->irq_ptr->schid);
+        unsigned int fc = QDIO_SIGA_SYNC;
         int cc;
 
         if (!need_siga_sync(q))
@@ -288,7 +292,12 @@ static inline int qdio_siga_sync(struct qdio_q *q, unsigned int output,
         DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-s:%1d", q->nr);
         qperf_inc(q, siga_sync);
 
-        cc = do_siga_sync(q->irq_ptr->schid, output, input);
+        if (is_qebsm(q)) {
+                schid = q->irq_ptr->sch_token;
+                fc |= QDIO_SIGA_QEBSM_FLAG;
+        }
+
+        cc = do_siga_sync(schid, output, input, fc);
         if (cc)
                 DBF_ERROR("%4x SIGA-S:%2d", SCH_NO(q), cc);
         return cc;
@@ -314,8 +323,8 @@ static inline int qdio_siga_sync_all(struct qdio_q *q)
 
 static int qdio_siga_output(struct qdio_q *q, unsigned int *busy_bit)
 {
-        unsigned long schid;
-        unsigned int fc = 0;
+        unsigned long schid = *((u32 *) &q->irq_ptr->schid);
+        unsigned int fc = QDIO_SIGA_WRITE;
         u64 start_time = 0;
         int cc;
 
@@ -324,11 +333,8 @@ static int qdio_siga_output(struct qdio_q *q, unsigned int *busy_bit)
 
         if (is_qebsm(q)) {
                 schid = q->irq_ptr->sch_token;
-                fc |= 0x80;
+                fc |= QDIO_SIGA_QEBSM_FLAG;
         }
-        else
-                schid = *((u32 *)&q->irq_ptr->schid);
-
 again:
         cc = do_siga_output(schid, q->mask, busy_bit, fc);
 
@@ -348,12 +354,19 @@ again:
 
 static inline int qdio_siga_input(struct qdio_q *q)
 {
+        unsigned long schid = *((u32 *) &q->irq_ptr->schid);
+        unsigned int fc = QDIO_SIGA_READ;
         int cc;
 
         DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-r:%1d", q->nr);
         qperf_inc(q, siga_read);
 
-        cc = do_siga_input(q->irq_ptr->schid, q->mask);
+        if (is_qebsm(q)) {
+                schid = q->irq_ptr->sch_token;
+                fc |= QDIO_SIGA_QEBSM_FLAG;
+        }
+
+        cc = do_siga_input(schid, q->mask, fc);
         if (cc)
                 DBF_ERROR("%4x SIGA-R:%2d", SCH_NO(q), cc);
         return cc;