s390/sclp: make early sclp irq handler more robust

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Make the early sclp interrupt handler more robust:

- disable all interrupt sub classes except for the service signal subclass
- extend ctlreg0 union so it is easily possible to set the service signal
  subclass mask bit without using a magic number
- disable lowcore protection before writing to it
- make sure that all write accesses are done before the original content
  of control register 0 is restored, which could enable lowcore protection

Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

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Heiko Carstens 2017-01-11 09:14:45 +01:00 • committed by Martin Schwidefsky

parent 68cc795d19

commit 742dc5773c

2 changed files with 13 additions and 6 deletions

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4

arch/s390/include/asm/ctl_reg.h

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15

arch/s390/kernel/sclp.c

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