random_adaptor is basically an adapter that plugs in to random(4).
random_adaptor can only be plugged in to random(4) very early in bootup.
Unplugging random_adaptor from random(4) is not supported, and is probably a
bad idea anyway, due to potential loss of entropy pools.
We currently have 3 random_adaptors:
+ yarrow
+ rdrand (ivy.c)
+ nehemeiah
* Remove platform dependent logic from probe.c, and move it into
corresponding registration routines of each random_adaptor provider.
probe.c doesn't do anything other than picking a specific random_adaptor
from a list of registered ones.
* If the kernel doesn't have any random_adaptor adapters present then the
creation of /dev/random is postponed until next random_adaptor is kldload'ed.
* Fix randomdev_soft.c to refer to its own random_adaptor, instead of a
system wide one.
Submitted by: arthurmesh@gmail.com, obrien
Obtained from: Juniper Networks
Reviewed by: so (des)
* Make Yarrow an optional kernel component -- enabled by "YARROW_RNG" option.
The files sha2.c, hash.c, randomdev_soft.c and yarrow.c comprise yarrow.
* random(4) device doesn't really depend on rijndael-*. Yarrow, however, does.
* Add random_adaptors.[ch] which is basically a store of random_adaptor's.
random_adaptor is basically an adapter that plugs in to random(4).
random_adaptor can only be plugged in to random(4) very early in bootup.
Unplugging random_adaptor from random(4) is not supported, and is probably a
bad idea anyway, due to potential loss of entropy pools.
We currently have 3 random_adaptors:
+ yarrow
+ rdrand (ivy.c)
+ nehemeiah
* Remove platform dependent logic from probe.c, and move it into
corresponding registration routines of each random_adaptor provider.
probe.c doesn't do anything other than picking a specific random_adaptor
from a list of registered ones.
* If the kernel doesn't have any random_adaptor adapters present then the
creation of /dev/random is postponed until next random_adaptor is kldload'ed.
* Fix randomdev_soft.c to refer to its own random_adaptor, instead of a
system wide one.
Submitted by: arthurmesh@gmail.com, obrien
Obtained from: Juniper Networks
Reviewed by: obrien
structure copying in random_ident_hardware(). This change will also help
further modularization of random(4) subsystem.
Submitted by: arthurmesh@gmail.com
Reviewed by: obrien
Obtained from: Juniper Networks
Specify that wakeup rate of 7.5-10Hz is enough for yarrow harvesting
thread.
Sponsored by: Google Summer of Code 2012, iXsystems inc.
Tested by: flo, marius, ian, markj, Fabian Keil
to kproc_xxx as they actually make whole processes.
Thos makes way for us to add REAL kthread_create() and friends
that actually make theads. it turns out that most of these
calls actually end up being moved back to the thread version
when it's added. but we need to make this cosmetic change first.
I'd LOVE to do this rename in 7.0 so that we can eventually MFC the
new kthread_xxx() calls.
if the specified priority is zero. This avoids a race where the calling
thread could read a snapshot of it's current priority, then a different
thread could change the first thread's priority, then the original thread
would call sched_prio() inside msleep() undoing the change made by the
second thread. I used a priority of zero as no thread that calls msleep()
or tsleep() should be specifying a priority of zero anyway.
The various places that passed 'curthread->td_priority' or some variant
as the priority now pass 0.
only allow proper values. ENTROPYSOURCE is a maxval+1, not an
allowable number.
Suggested loose protons in the solution: phk
Prefers to keep the pH close to seven: markm
supported for STAILQ via STAILQ_CONCAT().
(2) Maintain a count of the number of entries in the thread-local entropy
fifo so that we can keep the other fifo counts in synch.
MFC after: 3 weeks
MFC with: randomdev_soft.c revisions 1.5 and 1.6
Suggested by: jhb (1)
- Trade off granularity to reduce overhead, since the current model
doesn't appear to reduce contention substantially: move to a single
harvest mutex protecting harvesting queues, rather than one mutex
per source plus a mutex for the free list.
- Reduce mutex operations in a harvesting event to 2 from 4, and
maintain lockless read to avoid mutex operations if the queue is
full.
- When reaping harvested entries from the queue, move all entries from
the queue at once, and when done with them, insert them all into a
thread-local queue for processing; then insert them all into the
empty fifo at once. This reduces O(4n) mutex operations to O(2)
mutex operations per wakeup.
In the future, we may want to look at re-introducing granularity,
although perhaps at the granularity of the source rather than the
source class; both the new and old strategies would cause contention
between different instances of the same source (i.e., multiple
network interfaces).
Reviewed by: markm
full, avoiding the cost of mutex operations if it is. We re-test
once the mutex is acquired to make sure it's still true before doing
the -modify-write part of the read-modify-write. Note that due to
the maximum fifo depth being pretty deep, this is unlikely to improve
harvesting performance yet.
Approved by: markm
can more easily be used INSTEAD OF the hard-working Yarrow.
The only hardware source used at this point is the one inside
the VIA C3 Nehemiah (Stepping 3 and above) CPU. More sources will
be added in due course. Contributions welcome!
