Some systems seem to have gotten stuck in a softint processing loop
doing nothing and then trying to do it again. Might fix gson's
frozen qemu/anita sparc autobuilds -- tested on macallan's real sparc
hardware and confirmed to fix at least some freeze at boot.
There are three cases to consider here:
1. You have on-demand synchronous rndsources, e.g. RDRAND (and you're
willing to use it). In that case, you'll just use those whenever you
need to extract entropy. There's no benefit to requesting more from
them when we're entering data into the pool.
2. You have on-demand asynchronous rndsources. These should continue
trying to feed data to the entropy pool as long as it needs more, so
there's no benefit to requesting more from them when we're entering
data into the pool.
3. You don't have any on-demand rndsources. Then rnd_getmore does
nothing, so there's no benefit to calling it.
ok tls
Avoids lock recursion in rndsinks:
rndsink user holds lock
calls rndsink_request
calls rnd_getmore
calls an rndsource callback
calls rnd_add_data
calls rnd_process_events
calls rndsinks_distribute
calls rndsink callback
acquires rndsink user lock.
This can happen only before the rnd_process_events softint is
established, but that's enough to cause a problem and is the main
reason why all our HWRNG drivers are so byzantine (soon to be
fixed!).
ok tls
Let "el.h" include everything needed for struct editline,
and don't include that stuff multiple times. That also improves
consistency, also avoids circular inclusions, and also makes it
easier to follow what is going on, even though not quite as nice.
But it seems like the best we can do...
xennet_stop()) so that we don't get events while slepping (e.g.
in softint_disestablish()) when some structures have already been
freed.
Problem reported and patch tested by Rohan Desai.
The workaround was introduced because lltable/llentry uses rwlock
but it may be executed in hardware interrupt due to fast forward.
Now we don't run fast forward in hardware interrupt anymore, so
we can remove the workaround.
christos