Provide a wrapper for the INVPCID instruction, definition of the
descriptor and symbolic names for the operation types.

Sponsored by:	The FreeBSD Foundation
Reviewed by:	alc
Tested by:	pho, bf
Add BIT_AND_ATOMIC() and CPU_AND_ATOMIC().

Sponsored by:	The FreeBSD Foundation
Reviewed by:	alc
Tested by:	pho, bf
Implement support for the process-context identifiers ('PCID') on
Intel CPUs.  The feature tags TLB entries with the Id of the address
space and allows to avoid TLB invalidation on the context switch, it
is available only in the long mode.  In the microbenchmarks, using the
PCID decreased latency of the context switches by ~30% on SandyBridge
class desktop CPUs, measured with the lat_ctx program from lmbench.

If available, use INVPCID instruction when a TLB entry in non-current
address space needs to be invalidated.  The instruction is typically
available on the Haswell.

If needed, the use of PCID can be turned off with the
vm.pmap.pcid_enabled loader tunable set to 0.  The state of the
feature is reported by the vm.pmap.pcid_enabled sysctl.  The sysctl
vm.pmap.pcid_save_cnt reports the number of context switches which
avoided invalidating the TLB; compare with the total number of context
switches, available as sysctl vm.stats.sys.v_swtch.

Sponsored by:	The FreeBSD Foundation
Reviewed by:	alc
Tested by:	pho, bf
Typo in strtol(3).

Noticed by:	bde
Simplify pause_sbt() logic. Don't call DELAY() if remainder is less
than or equal to zero.
sh: Cast -1 to pointer rather than pointer to variable of wrong type.

NEOF needs to be a non-null pointer distinct from valid union node pointers.
It is not dereferenced.

The new NEOF is much like SIG_ERR except that it is an object pointer
instead of a function pointer.

The variable tokpushback can now be static.
The round of expand_number() cleanups.
o Fix range error checking to detect overflow when uint64_t < uintmax_t.
o Remove a non-functional check for no valid digits as pointed out by Bruce.
o Remove a rather pointless comment describing what the function does.
o Clean up a bunch of style bugs.

Brucified by:	bde
MFC
Separate out the Software RNG entropy harvesting queue and thread into its own files.

Submitted by:	 Arthur Mesh <arthurmesh@gmail.com>
sh: Recognize "--" as end of options in type builtin.

This implementation makes minimal changes: command names starting with "-"
(other than "--") can still be queried normally.
sh: Add a function for the case where one token is required in the parse.
A final test with unmodified code has shown that a delay of 150ms
is not giving us a 100% success rate. Bump the delay to 200ms as
that seems to do the trick.

Note that during testing the delay was added to uart_bus_attach()
in uart_core.c. While having the delay in a different place can
change the behaviour, it was not expected. Having to bump the
delay with another 50ms could therefore be an indication that
the problem can not be solved with delays.

Reported by: kevlo@
Tested by: kevlo@
Remove short-lived idea; thread to harvest (eg) RDRAND enropy into the usual harvest queues. It was a nifty idea, but too heavyweight.

Submitted by:	Arthur Mesh <arthurmesh@gmail.com>
Pull in r189672 from upstream llvm trunk:

  InstCombine: Check for zero shift amounts before subtracting one
  causing integer overflow.

  PR17026. Also avoid undefined shifts and shift amounts larger than 64
  bits (those are always undef because we can't represent integer types
  that large).

This should fix assertion failures when building the emulators/xmame
port.

Reported by:	bapt
acpi_thermal: Warn about insane _TMP temperature only once

A warning is emitted again if the temperature became briefly valid
meanwhile. This avoids spamming the user when the sensor is broken.

Other values (ie. not _TMP) always raise a warning.
Style cleanups.
The pm_save should be cleared on the pmap initialization, and not on
the activation.

Noted by:	alc
Give the page allocations initiated by the swap-backed md(4) a higher
priority.  If the write is requested by a system daemon, sleeping
there would starve resources and cause deadlock.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
sh: Use makename() where possible.
mdoc: add missing El.