The new NFS server would not allow a hard link to be
created to a symlink. This restriction (which was
inherited from OpenBSD) is not required by the NFS RFCs.
Since this is allowed by the old NFS server, it is a
POLA violation to not allow it. This patch modifies the
new NFS server to allow this.

Reported by:	jhb
Reviewed by:	jhb
MFC after:	3 days
Add Ukranian vt(4) keymaps as an example.

Sponsored by:	The FreeBSD Foundation
Add support for inspecting process flags set in p_flag2.

Reviewed by:	jhb
MFC after:	1 week
Add Makefiles to automatically test all the DTS files.

There are several broken DTS files right now in the arm directory.
Fix the script to run make_dtb.sh instead of just dtc.
Mov p2041rdb.dts, p3041ds.dts, and p5020ds.dts to the powerpc directory.
Some further DWC OTG improvements for full speed and low speed devices:
- Revert r265427. It appears we are halting the DWC OTG host
controller schedule if we process events only at every SOF. When doing
split transactions we rely on that events are processed quickly and
waiting too long might cause data loss.
- We are not always able to meet the timing requirements of interrupt
endpoint split transactions. Switch from INTERRUPT to CONTROL endpoint
type for interrupt endpoint events until further, hence CONTROL
endpoint events are more relaxed, reducing the chance of data
loss. See comment in code for more in-depth explanation.
- Simplify TT scheduling.

MFC after:	3 days
Fix for USB specification compliance. We need to accept both DATA0 and
DATA1 for INTERRUPT endpoints.

MFC after:	3 days
Make WITNESS happy by giving USB mutexes different names.

Reported by:	trociny @
MFC after:	3 days
Add a page size field to struct vm_page.  Increase the page size field when
a partially populated reservation becomes fully populated, and decrease this
field when a fully populated reservation becomes partially populated.

Use this field to simplify the implementation of pmap_enter_object() on
amd64, arm, and i386.

On all architectures where we support superpages, the cost of creating a
superpage mapping is roughly the same as creating a base page mapping.  For
example, both kinds of mappings entail the creation of a single PTE and PV
entry.  With this in mind, use the page size field to make the
implementation of vm_map_pmap_enter(..., MAP_PREFAULT_PARTIAL) a little
smarter.  Previously, if MAP_PREFAULT_PARTIAL was specified to
vm_map_pmap_enter(), that function would only map base pages.  Now, it will
create up to 96 base page or superpage mappings.

Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
Add ioctl(VM_REINIT) to reinitialize the virtual machine state maintained
by vmm.ko. This allows the virtual machine to be restarted without having
to destroy it first.

Reviewed by:	grehan
Remove unused variable.

Sponsored by:	Yandex LLC
Introduce new per-thread lock to protect the list of requests.

This allows to slightly simplify svc_run_internal() code: if we processed
all the requests in a queue, then we know that new one will not appear.

MFC after:	2 weeks
Remove st_idle variable, duplicating st_xprt.

MFC after:	2 weeks
Initialize the pbuf counter for directio using SYSINIT, instead of
using a direct hook called from kern_vfs_bio_buffer_alloc().
Mark ffs_rawread.c as requiring both ffs and directio options to be
compiled into the kernel.  Add ffs_rawread.c to the list of ufs.ko
module' sources.

In addition to stopping breaking the layering violation, it also
allows to link kernel when FFS is configured as module and DIRECTIO is
enabled.

One consequence of the change is that ffs_rawread.o is always linked
into the module regardless of the DIRECTIO option.  This is similar to
the option QUOTA and ufs_quota.c.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Remove write-only local variable.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Split RPC pool threads into number of smaller semi-isolated groups.

Old design with unified thread pool was good from the point of thread
utilization.  But single pool-wide mutex became huge congestion point
for systems with many CPUs.  To reduce the congestion create several
thread groups within a pool (one group for every 6 CPUs and 12 threads),
each group with own mutex.  Each connection during its registration is
assigned to one of the groups in round-robin fashion.  File affinify
code may still move requests between the groups, but otherwise groups
are self-contained.

MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.
In preparation for ASLR [1] support add WITH_PIE to support building with -fPIE

This is currently an opt-in flag. Once ASLR support is ready and stable it
should changed to opt-out and be enabled by default along with ASLR.

Mark known build failures as NO_PIE for now.

The only known runtime failure was rtld.

[1] http://www.bsdcan.org/2014/schedule/events/452.en.html
Submitted by:		Shawn Webb <lattera@gmail.com>
Discussed between:	des, imp, Shawn Webb