Timecounter registration is dynamic, i.e., there is no requirement that
timecounters must be registered during single-threaded boot.  Loadable
drivers may in principle register timecounters (which can be switched to
automatically).  Timecounters cannot be unregistered, though this could
be implemented.

Registered timecounters belong to a global linked list.  Add a mutex to
synchronize insertions and the traversals done by (mpsafe) sysctl
handlers.  No functional change intended.

Reviewed by:	imp, kib
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32511

This is obsolete since commit 8c576a279ed5 ("Remove APM BIOS support").

Reviewed by:	imp, kib
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32510

Add a SIG_FOREACH macro that can be used to iterate over a signal set.
This is a bit cleaner and more efficient than calling sig_ffs() in a
loop.  The implementation is based on BIT_FOREACH_ISSET(), except
that the bitset limbs are always 32 bits wide, and signal sets are
1-indexed rather than 0-indexed like bitset(9) sets.

issignal() cannot really be modified to use SIG_FOREACH() directly.
Take this opportunity to split the function into two explicit loops.
I've always found this function hard to read and think that this change
is an improvement.

Remove sig_ffs(), nothing uses it now.

Reviewed by:	kib
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32473

This implementation is faster and doesn't modify the cpuset, so it lets
us avoid some unnecessary copying as well.  No functional change
intended.

This is a re-application of commit
9068f6ea697b1b28ad1326a4c7a9ba86f08b985e.

Reviewed by:	cem, kib, jhb
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32029

Eliminate the nested loops and re-implement following a suggestion from
rlibby.

Add some simple regression tests.

Reviewed by:	rlibby, kib
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32472

The condition added in commit 5bdb8b273aaf excludes plain SHA
transforms, so for such sessions crypto operations would return
incorrect results.

Fixes:	5bdb8b273aaf ("safexcel: Maintain per-session context records")
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation

The root page is not zeroed at allocation time since with 4-level tables
each entry is copied from a template.  However, with 5-level tables only
a single entry is filled, so the rest need to be cleared.

Reported by:	alc
Reviewed by:	alc, kib
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32525

This patch modifies the function that does the Close RPC (nfsrpc_closerpc)
so that it does not use the open_owner (nfso_own) for NFSv4.1/4.2.
Use of the seqid in the open_owner structure is only needed for NFSv4.0.
Same applies to a NFSERR_STALESTATEID reply, which should only happen
for NFSv4.0.  This allows nfsrpc_closerpc() to be called when nfso_own
is no longer valid.  This, in turn, allows nfsrpc_closerpc() to be called
after the shared lock on the clientID is released, for NFSv4.1/4.2.

This is being done to prepare the code for a future patch that fixes
the case where an NFSv4.1/4.2 server replies NFSERR_DELAY to a Close
operation.

MFC after:	2 week