This patch adds support for clock synchronization to an external time
reference (ETR). The external time reference sends an oscillator
signal and a synchronization signal every 2^20 microseconds to keep
the TOD clocks of all connected servers in sync. For availability
two ETR units can be connected to a machine. If the clock deviates
for more than the sync-check tolerance all cpus get a machine check
that indicates that the clock is out of sync. For the lovely details
how to get the clock back in sync see the code below.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Major cleanup of all s390 inline assemblies. They now have a common
coding style. Quite a few have been shortened, mainly by using register
asm variables. Use of the EX_TABLE macro helps as well. The atomic ops,
bit ops and locking inlines new use the Q-constraint if a newer gcc
is used. That results in slightly better code.
Thanks to Christian Borntraeger for proof reading the changes.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Add missing volatile to the get_clock / get_cycles inline assemblies
to avoid that consecutive calls get optimized away.
Signed-off-by: Andreas Krebbel <krebbel1@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Martin Schwidefsky
Heiko Carstens
Andreas Krebbel
Linus Torvalds