sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

linuxkpi: Move definition of `struct list_head` to <linux/types.h>

This is the case on Linux.

Reviewed by: manu
Approved by: manu
Differential Revision: https://reviews.freebsd.org/D38537

LinuxKPI: Constantly use _LINUXKPI_ prefix in include guards

MFC after: 1 week
Reviewed by: bz, emaste, hselasky, manu
Differential Revision: https://reviews.freebsd.org/D33562

LinuxKPI: add kernel_ulong_t typedef in linux/kernel.h.

Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D30438

Allow LinuxKPI types to be used in bootloaders, by checking for the
_STANDALONE definition.

No functional change intended.

MFC after: 1 week
Sponsored by: Mellanox Technologies // NVIDIA Networking

Implement aligned LinuxKPI types for u16, u32 and u64.
Makes a difference for 32-bit platforms mostly.

MFC after: 1 week
Sponsored by: Mellanox Technologies

Add ushort and ulong to linux/types.h.

When porting code once written for Linux we find not only uints but also ushort and ulong.
Provide central typedefs as part of the linuxkpi for those as well.

Reviewed by: hselasky, emaste
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19405

linux/fs: simplify interop and correct definition of loff_t

- offsets can be negative, loff_t needs to be signed, it also simplifies
interop with the rest of the code base to use off_t than the actual linux
definition "long long"
- don't rely on the defining "file" to "linux_file" in interface definitions
as that causes heartache with includes

Reviewed by: hps@
MFC after: 1 week
Sponsored by: iX Systems
Differential Revision: https://reviews.freebsd.org/D19274

Define __poll_t type in the LinuxKPI.

Submitted by: Johannes Lundberg <johalun0@gmail.com>
MFC after: 1 week
Sponsored by: Mellanox Technologies

Define the __kernel_size_t type in the LinuxKPI.

Submitted by: Johannes Lundberg <johalun0@gmail.com>
MFC after: 1 week
Sponsored by: Mellanox Technologies
Sponsored by: Limelight Networks

Add some miscellaneous definitions to support DRM drivers.

Reviewed by: hselasky
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D10985

Implement a series of physical page management related functions in
the LinuxKPI for accessing user-space memory in the kernel.

Add functions to hold and wire physical page(s) based on a given range
of user-space virtual addresses.

Add functions to get and put a reference on, wire, hold, mark
accessed, copy and dirty a physical page.

Add new VM related structures and defines as a preparation step for
advancing the memory map capabilities of the LinuxKPI.

Add function to figure out if a virtual address was allocated using
malloc().

Add function to convert a virtual kernel address into its physical
page pointer.

Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies

Update the LinuxKPI RCU and SRCU wrappers for the concurrency kit, CK.

- Optimise the RCU implementation to not allocate and free
ck_epoch_records during runtime. Instead allocate two sets of
ck_epoch_records per CPU for general purpose use. The first set is
only used for reader locks and the second set is only used for
synchronization and barriers and is protected with a regular mutex to
prevent simultaneous issues.

- Move the task structure away from the rcu_head structure and into
the per-CPU structures. This allows the size of the rcu_head structure
to be reduced down to the size of two pointers.

- Fix a bug where the linux_rcu_barrier() function only waited for one
per-CPU epoch record to be completed instead of all.

- Use a critical section or a mutex to protect ck_epoch_begin() and
ck_epoch_end() depending on RCU or SRCU type. All the ck_epoch_xxx()
functions, except ck_epoch_register(), ck_epoch_unregister() and
ck_epoch_recycle() are not re-entrant and needs a critical section or
a mutex to operate in the LinuxKPI, after inspecting the CK
implementation of the above mentioned functions. The simultaneous
issues arise from per-CPU epoch records being shared between multiple
threads depending on the amount of taskswitching and how many threads
are involved with the RCU and SRCU operations.

- Properly free all epoch records by using safe list traversal at
LinuxKPI module unload. It turns out the ck_epoch_recycle() always
have the records on an internal list and use a flag in the epoch
record to track allocated and free entries. This would lead to use
after free during module unload.

- Remove redundant synchronize_rcu() call from the
linux_compat_uninit() function. Let the linux_rcu_runtime_uninit()
function do the final rcu_barrier() instead.

MFC after: 1 week
Sponsored by: Mellanox Technologies

Define __sum16 type in the LinuxKPI.

MFC after: 1 week
Sponsored by: Mellanox Technologies

Replace dummy implementation of RCU in the LinuxKPI with one based on
the in-kernel concurrency kit's ck_epoch API. Factor RCU hlist_xxx()
functions into own rculist.h header file.

Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies

Make the LinuxKPI task struct persistent accross system calls.

A set of helper functions have been added to manage the life of the
LinuxKPI task struct. When an external system call or task is invoked,
a check is made to create the task struct by demand. A thread
destructor callback is registered to free the task struct when a
thread exits to avoid memory leaks.

This change lays the ground for emulating the Linux kernel more
closely which is a dependency by the code using the LinuxKPI APIs.

Add new dedicated td_lkpi_task field has been added to struct thread
instead of abusing td_retval[1].

Fix some header file inclusions to make LINT kernel build properly
after this change.

Bump the __FreeBSD_version to force a rebuild of all kernel modules.

MFC after: 1 week
Sponsored by: Mellanox Technologies

Finish process of moving the LinuxKPI module into the default kernel build.

- Move all files related to the LinuxKPI into sys/compat/linuxkpi and
its subfolders.
- Update sys/conf/files and some Makefiles to use new file locations.
- Added description of COMPAT_LINUXKPI to sys/conf/NOTES which in turn
adds the LinuxKPI to all LINT builds.
- The LinuxKPI can be added to the kernel by setting the
COMPAT_LINUXKPI option. The OFED kernel option no longer builds the
LinuxKPI into the kernel. This was done to keep the build rules for
the LinuxKPI in sys/conf/files simple.
- Extend the LinuxKPI module to include support for USB by moving the
Linux USB compat from usb.ko to linuxkpi.ko.
- Bump the FreeBSD_version.
- A universe kernel build has been done.

Reviewed by: np @ (cxgb and cxgbe related changes only)
Sponsored by: Mellanox Technologies