linux_old1/arch/s390
Heiko Carstens e8129c6421 [S390] nmi: fix clock comparator revalidation
On each machine check all registers are revalidated. The save area for
the clock comparator however only contains the upper most seven bytes
of the former contents, if valid.
Therefore the machine check handler uses a store clock instruction to
get the current time and writes that to the clock comparator register
which in turn will generate an immediate timer interrupt.
However within the lowcore the expected time of the next timer
interrupt is stored. If the interrupt happens before that time the
handler won't be called. In turn the clock comparator won't be
reprogrammed and therefore the interrupt condition stays pending which
causes an interrupt loop until the expected time is reached.

On NOHZ machines this can result in unresponsive machines since the
time of the next expected interrupted can be a couple of days in the
future.

To fix this just revalidate the clock comparator register with the
expected value.
In addition the special handling for udelay must be changed as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-11-25 09:52:59 +01:00
..
appldata [S390] appldata: fix dev_get_stats 64 bit conversion 2010-08-13 10:06:55 +02:00
boot [S390] Add support for LZO-compressed kernels. 2010-05-26 23:27:10 +02:00
crypto [S390] cleanup facility list handling 2010-10-25 16:10:21 +02:00
hypfs Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6 2010-10-29 08:49:18 -07:00
include/asm [S390] mm: add devmem_is_allowed() for STRICT_DEVMEM checking 2010-11-10 10:05:54 +01:00
kernel [S390] nmi: fix clock comparator revalidation 2010-11-25 09:52:59 +01:00
kvm [S390] cleanup facility list handling 2010-10-25 16:10:21 +02:00
lib [S390] nmi: fix clock comparator revalidation 2010-11-25 09:52:59 +01:00
math-emu tree-wide: fix assorted typos all over the place 2009-12-04 15:39:55 +01:00
mm [S390] fix get_user_pages_fast 2010-11-10 10:05:53 +01:00
oprofile Combine instrumentation menus in kernel/Kconfig.instrumentation 2007-10-19 11:53:54 -07:00
Kbuild [S390] standardize Kbuild rules 2010-10-25 16:10:14 +02:00
Kconfig [S390] ftrace: select HAVE_C_RECORDMCOUNT 2010-10-29 16:50:50 +02:00
Kconfig.debug [S390] mm: add devmem_is_allowed() for STRICT_DEVMEM checking 2010-11-10 10:05:54 +01:00
Makefile [S390] Add config option for z196 code generation. 2010-10-25 16:10:15 +02:00
defconfig defconfig reduction 2010-08-14 22:26:53 +02:00