s390/zcrypt: kernel oops at insmod of the z90crypt device driver

Kernel oops caused by invalid parameter at TAPQ instruction:
On older systems where the QCI instruction is not available
all possible domains are probed via TAPQ instruction. The
range for the probe has been extended with the > 16 domain
support now leading to a possible specification exception
when this instruction is called for probing higher values
within the new range. This may happen during insmod and/or
ap bus reset only on machines without a QCI instruction (z10,
z196, z114), zEC12 and newer systems are not affected.
The fix modifies the domain checking function to limit the
allowed range if no QCI info is available.

Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 91e97ec..4d41bf7 100644 (file)
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -1163,9 +1163,13 @@ static inline int ap_test_config_card_id(unsigned int id)
  */
 static inline int ap_test_config_domain(unsigned int domain)
 {
-       if (!ap_configuration)
-               return 1;
-       return ap_test_config(ap_configuration->aqm, domain);
+       if (!ap_configuration)    /* QCI not supported */
+               if (domain < 16)
+                       return 1; /* then domains 0...15 are configured */
+               else
+                       return 0;
+       else
+               return ap_test_config(ap_configuration->aqm, domain);
 }
 
 /**