Add a case to make sure that internal audit records get converted
to BSM format for lpathconf(2) events.

PR:		157946

* r233937 - Improve BPF locking model
* r233938 - Improve performace for writer-only BPF users
* r233946 - Fix build
* r235744 - Fix (new) panic on attaching to non-existent interface
* r235745 - Fix old panic when BPF consumer attaches to destroying interface
* r235746 - Call bpf_jitter() before acquiring BPF global lock
* r235747 - Make most BPF ioctls() SMP-safe.
* r236231 - Fix BPF_JITTER code broken by r235746.
* r236261 - Save the previous filter right before we set new one.
* r236262 - Fix style(9) nits, reduce unnecessary type castings.
* r236559 - Fix panic introduced by r235745
* r236806 - Fix typo introduced in r236559.

r233937
  - Improve BPF locking model.

  Interface locks and descriptor locks are converted from mutex(9) to rwlock(9).
  This greately improves performance: in most common case we need to acquire 1
  reader lock instead of 2 mutexes.

  - Remove filter(descriptor) (reader) lock in bpf_mtap[2]
  This was suggested by glebius@. We protect filter by requesting interface
  writer lock on filter change.

  - Cover struct bpf_if under BPF_INTERNAL define. This permits including bpf.h
  without including rwlock stuff. However, this is is temporary solution,
  struct bpf_if should be made opaque for any external caller.

r233938
  - Improve performace for writer-only BPF users.

  Linux and Solaris (at least OpenSolaris) has PF_PACKET socket families to send
  raw ethernet frames. The only FreeBSD interface that can be used to send raw
  frames is BPF. As a result, many programs like cdpd, lldpd, various dhcp stuff
  uses BPF only to send data. This leads us to the situation when software like
  cdpd, being run on high-traffic-volume interface significantly reduces overall
  performance since we have to acquire additional locks for every packet.

  Here we add sysctl that changes BPF behavior in the following way:
  If program came and opens BPF socket without explicitly specifyin read filter
  we assume it to be write-only and add it to special writer-only per-interface
  list. This makes bpf_peers_present() return 0, so no additional overhead is
  introduced. After filter is supplied, descriptor is added to original
  per-interface list permitting packets to be captured.

  Unfortunately, pcap_open_live() sets catch-all filter itself for the purpose
  of setting snap length.

  Fortunately, most programs explicitly sets (event catch-all) filter after
  that. tcpdump(1) is a good example.

  So a bit hackis approach is taken: we upgrade description only after second
  BIOCSETF is received.

  Sysctl is named net.bpf.optimize_writers and is turned off by default.

  - While here, document all sysctl variables in bpf.4

r233946
  Fix build broken by r233938.

r235744
  Fix panic on attaching to non-existent interface
	(introduced by r233937, pointed by hrs@)
  Fix panic on tcpdump being attached to interface being removed
	(introduced by r233937, pointed by hrs@ and adrian@)
  Protect most of bpf_setf() by BPF global lock

  Add several forgotten assertions (thanks to adrian@)

  Document current locking model inside bpf.c
  Document EVENTHANDLER(9) usage inside BPF.

r235745
  Fix old panic when BPF consumer attaches to destroying interface.
  'flags' field is added to the end of bpf_if structure. Currently the only
  flag is BPFIF_FLAG_DYING which is set on bpf detach and checked by bpf_attachd()
  Problem can be easily triggered on SMP stable/[89] by the following command
  (sort of):
  'while true; do ifconfig vlan222 create vlan 222 vlandev em0 up ; \
    tcpdump -pi vlan222 & ; ifconfig vlan222 destroy ; done'

  Fix possible use-after-free when BPF detaches itself from interface, freeing
  bpf_bif memory, while interface is still UP and there can be routes via this
  interface. Freeing is now delayed till ifnet_departure_event is received via
  eventhandler(9) api.

  Convert bpfd rwlock back to mutex due lack of performance gain
  (currently checking if packet matches filter is done without holding bpfd
   lock and we have to acquire write lock if packet matches)

r235746
  Call bpf_jitter() before acquiring BPF global lock due to malloc() being
  used inside bpf_jitter.

  Eliminate bpf_buffer_alloc() and allocate BPF buffers on descriptor creation
   and BIOCSBLEN ioctl. This permits us not to allocate buffers inside
   bpf_attachd() which is protected by global lock.

r235747
  Make most BPF ioctls() SMP-safe.

r236559
  Fix panic introduced by r235745. Panic occurs after first packet traverse
  renamed interface.
  Add several comments on locking

r236231
  Fix BPF_JITTER code broken by r235746.

r236261
  - Save the previous filter right before we set new one.
  - Reduce duplicate code and make it little easier to read.

r236262
  Fix style(9) nits, reduce unnecessary type castings, etc., for bpf_setf().

r236806
  Fix typo introduced in r236559.

  When allocation of labels on files is implicitly disabled due to MAC
  policy configuration, avoid leaking resources following failed calls
  to get and set MAC labels by file descriptor.

  Reported by:    Mateusz Guzik <mjguzik at gmail.com> + clang scan-build

Check vplabel for NULL before dereferencing it.  Fixes a panic
when running atop with MAC_MLS enabled.

stopping other CPUs in SMP case

Introduce and use seldrain() function for dealing with fast
selrecord/selinfo destruction.

Sponsored by:	Sandvine Incorporated

r209721:

  Merge from vendor-sys/opensolaris:
  * add fasttrap files

r209731:

  Introduce USD_{SET,GET}{BASE,LIMIT}. These help setting up the user
  segment descriptor hi and lo values. Idea from Solaris.

  Reviewed by:  kib

r209763:

  Fix style issues with the previous commit, namely
  use-tab-instead-of-space and don't use underscores in macro variables.

  Pointed out by:       bde

r210292:

  Fix typo in comment.

r210357:

  MFamd64:
    Add USD_GETBASE(), USD_SETBASE(), USD_GETLIMIT() and USD_SETLIMIT().

r210611:

  Bump the witness pendlist to 768 to accomodate the increased number of
  spinlocks.

r211553:

  Add sysname to struct opensolaris_utsname. This is needed by one DTrace
  test.

r211566:

  Add a sysname char * to struct opensolaris_utsname.

r211606:

  Add the FreeBSD definition for the fasttrap ioctls.

r211607:

  Add a function compatibility function dtrace_instr_size_isa() that on
  FreeBSD does the same as dtrace_dis_isize().

r211608:

  Kernel DTrace support for:
  o uregs  (sson@)
  o ustack (sson@)
  o /dev/dtrace/helper device (needed for USDT probes)

r211610:

  Add more compatibility structure members needed by the upcoming fasttrap
  DTrace device.

r211611:

  Destroy the helper device when unloading.

r211613:

  Fix style issues.

r211614:

  Bump KDTRACE_THREAD_ZERO and use M_ZERO as a malloc flag instead of
  calling bzero.

r211615:

  Remove an elif and add an or-clause.

r211616:

  Add an extra comment to the SDT probes definition. This allows us to get
  use '-' in probe names, matching the probe names in Solaris.

  Add userland SDT probes definitions to sys/sdt.h.

r211617:

  Call the systrace_probe_func() when the error value.

r211618:

  Port this to FreeBSD. We miss some suword functions, so we use copyout.

r211738:

  Port the fasttrap provider to FreeBSD. This provider is responsible for
  injecting debugging probes in the userland programs and is the basis for
  the pid provider and the usdt provider.

r211744:

  MD fasttrap implementation.

r211745:

  Replace a pksignal() call with tdksignal().

  Pointed out by:       kib

r211746:

  Update for the recent location of the fasttrap code.

r211747:

  Replace structure assignments with explicity memcpy calls. This allows
  Clang to compile this file: it was using the builtin memcpy and we want
  to use the memcpy defined in gptboot.c. (Clang can't compile boot2 yet).

  Submitted by: Dimitry Andric <dimitry at andric.com>
  Reviewed by:  jhb

r211751:

  Add a trap code for DTrace induced traps.

r211752:

  Add two DTrace trap type values. Used by fasttrap.

r211753:

  Enable fasttrap and make dtraceall depend on fasttrap when building i386
  or amd64.

r211804:

  Call the necessary DTrace function pointers when we have different kinds
  of traps.

r211813:

  Add the necessary DTrace function pointers.

r211839:

  Sync DTrace bits with amd64 and fix the build.

r211924:

  Register an interrupt vector for DTrace return probes. There is some
  code missing in lapic to make sure that we don't overwrite this entry,
  but this will be done on a sequent commit.

r211925:

  Replace a memory barrier with a mutex barrier.

r211926:

  Add the path necessary to find fasttrap_isa.h to CFLAGS.

r211929:

  Remove debugging.

r212004:

  When DTrace is enabled, make sure we don't overwrite the IDT_DTRACE_RET
  entry with an IRQ for some hardware component.

  Reviewed by:  jhb

r212093:

  Make the /dev/dtrace/helper node have the mode 0660. This allows
  programs that refuse to run as root (pgsql) to install probes when their
  user is part of the wheel group.

r212357:

  Fix two bugs in DTrace:
  * when the process exits, remove the associated USDT probes
  * when the process forks, duplicate the USDT probes.

r212465:

  Avoid a LOR (sleepable after non-sleepable) in
  fasttrap_tracepoint_enable().

r212494:

  Revamp locking a bit. This fixes three problems:
  * processes now can't go away while we are inserting probes (fixes a panic)
  * if a trap happens, we won't be holding the process lock (fixes a hang)
  * fix a LOR between the process lock and the fasttrap bucket list lock

  Thanks to kib for pointing some problems.

r212568:

  Bump __FreeBSD_version to reflect the userland DTrace changes

Sponsored by:                   The FreeBSD Foundation
Userspace DTrace work by:       rpaulo