Commit a745333f authored by Heiko Carstens's avatar Heiko Carstens Committed by Greg Kroah-Hartman

KVM: s390: sthyi: fix sthyi inline assembly

commit 4a4eefcd upstream.

The sthyi inline assembly misses register r3 within the clobber
list. The sthyi instruction will always write a return code to
register "R2+1", which in this case would be r3. Due to that we may
have register corruption and see host crashes or data corruption
depending on how gcc decided to allocate and use registers during
compile time.

Fixes: 95ca2cb5 ("KVM: s390: Add sthyi emulation")
Reviewed-by: default avatarJanosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 963068b1
......@@ -394,7 +394,7 @@ static int sthyi(u64 vaddr)
"srl %[cc],28\n"
: [cc] "=d" (cc)
: [code] "d" (code), [addr] "a" (addr)
: "memory", "cc");
: "3", "memory", "cc");
return cc;
}
......
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