1) Move core entropy-pool code and source/sink/sample management code
to sys/kern from sys/dev.
2) Remove use of NRND as test for presence of entropy-pool code throughout
source tree.
3) Remove use of RND_ENABLED in device drivers as microoptimization to
avoid expensive operations on disabled entropy sources; make the
rnd_add calls do this directly so all callers benefit.
4) Fix bug in recent rnd_add_data()/rnd_add_uint32() changes that might
have lead to slight entropy overestimation for some sources.
5) Add new source types for environmental sensors, power sensors, VM
system events, and skew between clocks, with a sample implementation
for each.
ok releng to go in before the branch due to the difficulty of later
pullup (widespread #ifdef removal and moved files). Tested with release
builds on amd64 and evbarm and live testing on amd64.
and sysinst may learn to write it (since, on some systems, most of
the keyboard input they ever get happens to be during install). Fix a
couple of minor problems with the random_seed rc script addition.
at system shutdown. Disable with random_seed=NO in rc.conf if desired.
Goes to some trouble to never load or save to network filesystems.
Entropy should really be loaded by the boot loader but I am still
sorting out how to pass it to the kernel.
