tree 51794f46cb7fc7fa4db8fbadb8feb265fc8ef499
parent 902050bcdece6191565c055539e82c5cc534feed
author Heiko Carstens <heiko.carstens@de.ibm.com> 1306396103 +0200
committer Heiko Carstens <heiko.carstens@de.ibm.com> 1306396104 +0200

[S390] irq: fix service signal external interrupt handling

Interrupt sources like pfault, sclp, dasd_diag and virtio all use the
service signal external interrupt subclass mask in control register 0
to enable and disable the corresponding interrupt.
Because no reference counting is implemented each subsystem thinks it
is the only user of subclass and sets and clears the bit like it wants.
This leads to case that unloading the dasd diag module under z/VM
causes both sclp and pfault interrupts to be masked. The result will
be locked up system sooner or later.
Fix this by introducing a new way to set (register) and clear
(unregister) the service signal subclass mask bit in cr0.
Also convert all drivers.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>