linux/arch/s390
Heiko Carstens d3d238c774 [S390] nohz: Fix __udelay.
This fixes a regression that came with 934b2857cc
("[S390] nohz/sclp: disable timer on synchronous waits.").
If udelay() gets called from a disabled context it sets the clock comparator
to a value where it expects the next interrupt. When the interrupt happens
the clock comparator gets not reset and therefore the interrupt condition
doesn't get cleared. The result is an endless timer interrupt loop.

In addition this patch fixes also the following:

rcutorture reveals that our __udelay implementation is still buggy,
since it might schedule tasklets, but prevents their execution:

NOHZ: local_softirq_pending 42
NOHZ: local_softirq_pending 02
NOHZ: local_softirq_pending 142
NOHZ: local_softirq_pending 02

To fix this we make sure that only the clock comparator interrupt
is enabled when the enabled wait psw is loaded.
Also no code gets called anymore which might schedule tasklets.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-10-03 21:55:54 +02:00
..
appldata Merge branch 'generic-ipi' into generic-ipi-for-linus 2008-07-15 21:55:59 +02:00
boot
crypto Merge branch 'bkl-removal' of git://git.lwn.net/linux-2.6 2008-07-14 14:48:31 -07:00
hypfs [S390] s390: use simple_read_from_buffer() 2008-07-14 10:02:16 +02:00
include/asm [S390] fix ext2_find_next_bit 2008-08-21 19:46:41 +02:00
kernel [S390] nohz: Fix __udelay. 2008-10-03 21:55:54 +02:00
kvm KVM: s390: Fix kvm on IBM System z10 2008-07-31 11:57:18 +03:00
lib [S390] nohz: Fix __udelay. 2008-10-03 21:55:54 +02:00
math-emu [S390] remove -traditional 2008-04-30 13:38:44 +02:00
mm [S390] Add support for memory hot-remove. 2008-08-01 16:39:33 +02:00
oprofile Combine instrumentation menus in kernel/Kconfig.instrumentation 2007-10-19 11:53:54 -07:00
defconfig [S390] Update default configuration. 2008-08-21 19:46:42 +02:00
Kconfig [S390] Add support for memory hot-remove. 2008-08-01 16:39:33 +02:00
Kconfig.debug [S390] DEBUG_PAGEALLOC support for s390. 2008-02-05 16:50:54 +01:00
Makefile KVM: s390: arch backend for the kvm kernel module 2008-04-27 12:00:42 +03:00