LinuxKPI: Allow kmalloc to be called when FPU protection is enabled

Amdgpu driver does a lot of memory allocations in FPU-protected sections
of code for certain display cores, e.g. for DCN30. This does not work
on FreeBSD as its malloc function can not be run within a critical
section. Check this condition and temporally exit from FPU-protected
context to workaround issue and reduce source code patching.

Sponsored by: Serenity Cyber Security, LLC
Reviewed by: manu (previous version)
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D42822

Revert "LinuxKPI: Add explicit software context to FPU sections"

kmalloc() support within FPU sections will be redone in other way.

This reverts commit 5a3bd281672bd6bd8e18081c3928dfe76d330a5f.

Sponsored by: Serenity Cyber Security, LLC
Requested by: jhb

Revert "LinuxKPI: Do not use explicit context in FPU sections on powerpc64"

kmalloc() support within FPU sections will be redone in other way.

This reverts commit b4efc62776344a9aaada5a0866e453e528a0e977.

Sponsored by: Serenity Cyber Security, LLC
Requested by: jhb

LinuxKPI: Do not use explicit context in FPU sections on powerpc64

It is not supported yet.

Sponsored by: Serenity Cyber Security, LLC
Fixes: 5a3bd281672b ("LinuxKPI: Add explicit software context to FPU sections")
MFC after: 1 week

LinuxKPI: Add explicit software context to FPU sections

Amdgpu driver does a lot of memory allocations in FPU-protected sections
of code for certain display cores, e.g. for DCN30. This does not work
currently on FreeBSD as its malloc function can not be run within a
critical section. Allocate memory for FPU context to overcome such
restriction.

Sponsored by: Serenity Cyber Security, LLC
Reviewed by: manu (previous version), markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D42822

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

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

linuxkpi: Add compat_ptr and ptr_to_compat

Needed by drm-kmod.

Obtained from: drm-kmod
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D36016

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

Implement basic support for allocating memory from a specific numa node
in the LinuxKPI.

Differential Revision: https://reviews.freebsd.org/D29077
Reviewed by: markj@ and kib@
MFC after: 1 week
Sponsored by: Mellanox Technologies // NVIDIA Networking

compat: clean up empty lines in .c and .h files

lkpi: allow late binding of linux_alloc_current

Some consumers may be loosely coupled with the lkpi.
This allows them to call linux_alloc_current without
having a static dependency.

Reviewed by: hps@
MFC after: 1 week
Sponsored by: iX Systems
Differential Revision: https://reviews.freebsd.org/D19257

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

Set "current" for all PCI enumeration callbacks.

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

Remove incorrect defines. The proper version of these macros is
defined in linux/etherdevice.h.

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