linux/arch/s390/lib
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
..
delay.c [S390] nmi: fix clock comparator revalidation 2010-11-25 09:52:59 +01:00
div64.c [S390] __div64_31 broken for CONFIG_MARCH_G5 2009-03-18 13:28:12 +01:00
Makefile [S390] uaccess: make sure copy_from_user_overflow is builtin 2010-03-08 12:25:29 +01:00
qrnnd.S [S390] Calibrate delay and bogomips. 2007-02-05 21:18:31 +01:00
spinlock.c [S390] spinlock: check virtual cpu running status 2010-02-26 22:37:31 +01:00
string.c [S390] use compiler builtin versions of strlen/strcpy/strcat 2009-03-26 15:24:24 +01:00
uaccess_mvcos.c [S390] Improve address space mode selection. 2009-12-07 12:51:33 +01:00
uaccess_pt.c [S390] Use do_exception() in pagetable walk usercopy functions. 2009-12-07 12:51:34 +01:00
uaccess_std.c [S390] Add EX_TABLE for addressing exception in usercopy functions. 2009-10-06 10:35:10 +02:00
uaccess.h [S390] Get rid of a lot of sparse warnings. 2007-02-05 21:16:47 +01:00
ucmpdi2.c [S390] add __ucmpdi2() helper function 2009-07-07 16:37:53 +02:00
usercopy.c [S390] uaccess: implement strict user copy checks 2010-02-26 22:37:29 +01:00