s390/runtime_instrumentation: fix storage key handling

The key member of the runtime instrumentation control block contains
only the access key, not the complete storage key. Therefore the value
must be shifted by four bits.
Note: this is only relevant for debugging purposes in case somebody
compiles a kernel with a default storage access key set to a value not
equal to zero.

Fixes: e4b8b3f33fca ("s390: add support for runtime instrumentation")
Reported-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/arch/s390/kernel/runtime_instr.c b/arch/s390/kernel/runtime_instr.c
index 125c7f6e87150d526a60c9e23b99c47bad1aae2b..1788a5454b6fc7a3a64b621b9b1880e35d6b705d 100644 (file)
--- a/arch/s390/kernel/runtime_instr.c
+++ b/arch/s390/kernel/runtime_instr.c
@@ -57,7 +57,7 @@ static void init_runtime_instr_cb(struct runtime_instr_cb *cb)
        cb->k = 1;
        cb->ps = 1;
        cb->pc = 1;
-       cb->key = PAGE_DEFAULT_KEY;
+       cb->key = PAGE_DEFAULT_KEY >> 4;
        cb->v = 1;
 }