s390/sclp: Add SCLP character device driver
Add a character misc device "sclp_ctl" that allows to run SCCBs
from user space using the SCLP_CTL_SCCB ioctl.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index a77febe..97319d6 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -148,14 +148,19 @@
int
sclp_service_call(sclp_cmdw_t command, void *sccb)
{
- int cc;
+ int cc = 4; /* Initialize for program check handling */
asm volatile(
- " .insn rre,0xb2200000,%1,%2\n" /* servc %1,%2 */
- " ipm %0\n"
- " srl %0,28"
- : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
+ "0: .insn rre,0xb2200000,%1,%2\n" /* servc %1,%2 */
+ "1: ipm %0\n"
+ " srl %0,28\n"
+ "2:\n"
+ EX_TABLE(0b, 2b)
+ EX_TABLE(1b, 2b)
+ : "+&d" (cc) : "d" (command), "a" (__pa(sccb))
: "cc", "memory");
+ if (cc == 4)
+ return -EINVAL;
if (cc == 3)
return -EIO;
if (cc == 2)