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

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

Make SMCCC usable by device drivers

To allow device drivers to call into SMCCC we need to initialise it
earlier. As it depends on PSCI, and that is detected via ACPI or FDT
move the call to smccc_init to the PSCI driver.

Add a function for drivers to read the smccc version, or 0 if smccc
is not present.

arm64: Enabling new hypercalls using HvCallSetVpRegisters and HvCallGetVpRegisters

Enabling HvCallSetVpRegisters and HvCallGetVpRegisters for hypercalls to
read and write to specific MSRs. This is required for implementing wrmsr
and rdmsr, which is required for Hyper-V vmbus driver for ARM64.

Also we need to use arm smccc hvc 1.2 version as we need to access
registers beyond X0-X3 for HvCallGetVpRegisters. Currently scoping
it only for Hyper-V.

Reviewed by: lwhsu, andrew, whu
Tested by: Souradeep Chakrabarti <schakrabarti@microsoft.com>
Signed-off-by: Souradeep Chakrabarti <schakrabarti@microsoft.com>
Sponsored by: Microsoft
Differential Revision: https://reviews.freebsd.org/D36256

Add generic arm/arm64 secure-monitor SMCCC interface and switch
PSCI code to use it.

This interface will also be used by Intel Stratix 10 platform.

This was not tested on arm due to lack of PSCI-enabled arm hardware
lying around.

Reviewed by: andrew
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D21439

Use int for the pcpu_ssbd argument. This is included from userland and may
not include the needed headers to get the bool definition.

Reported by: manu
Pointy hat to: andrew
Sponsored by: DARPA, AFRL

Implement the SSBD (CVE-2018-3639) workaround on arm64

This calls into the Arm Trusted Firmware to enable and disable the
workaround for the Speculative Store Bypass Disable (SSBD) issue, also
known as Spectre Variant 4.

As this may have a large performance overhead, and how exploitable SSBD is
is unknown we follow the Linux lead of allowing the administrator to select
between always on, always off, or only enabled in the kernel, with the
latter being the default.

PR: 228955
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D15819

Fix the SMCCC signatures, they are all 32-bit calls. This fixes SMCCC
version detection.

Sponsored by: DARPA, AFRL

Add the SMCCC return codes from ARM DEN 0070A.

While here add a comment with the document the function IDs come from.

Sponsored by: DARPA, AFRL

Add support for the ARM SMC Calling Convention (SMCCC). This is a method
to call into the firmware in a similar way to the existing PSCI, and used
PSCI to detect when SMCCC is enabled.

There is a function ID space we can use. Currently we only support 3
functions in the ARM Architecture Calls region, however it is expected we
will expend these in the future.

Sponsored by: DARPA, AFRL