s390-ccw: force diag 308 subcode to unsigned long

We currently pass an integer as the subcode parameter. However,
the upper bits of the register containing the subcode need to
be 0, which is not guaranteed unless we explicitly specify the
subcode to be an unsigned long value.

Fixes: d046c51dad3 ("pc-bios/s390-ccw: Get device address via diag 308/6")
Cc: qemu-stable@nongnu.org
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit 63d8b5ace31c1e1f3996fe4cd551d6d377594d5a)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/pc-bios/s390-ccw/iplb.h b/pc-bios/s390-ccw/iplb.h
index 40fc2d8e21562d933ae1be004e79ccc548560499..da0cab01021793ee6f6ba055cdf864a89cdbe939 100644 (file)
--- a/pc-bios/s390-ccw/iplb.h
+++ b/pc-bios/s390-ccw/iplb.h
@@ -81,10 +81,11 @@ static inline bool manage_iplb(IplParameterBlock *iplb, bool store)
 {
     register unsigned long addr asm("0") = (unsigned long) iplb;
     register unsigned long rc asm("1") = 0;
+    unsigned long subcode = store ? 6 : 5;
 
     asm volatile ("diag %0,%2,0x308\n"
                   : "+d" (addr), "+d" (rc)
-                  : "d" (store ? 6 : 5)
+                  : "d" (subcode)
                   : "memory", "cc");
     return rc == 0x01;
 }