Commit d3d238c7 authored by Committed by Martin SchwidefskyBrowse files
[S390] nohz: Fix __udelay.
This fixes a regression that came with 934b2857 ("[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 <firstname.lastname@example.org> Signed-off-by: Martin Schwidefsky <email@example.com>