Convert license tags to SPDX identifiers

This commit also converts our own copyright headers to directly use
SPDX, but leaves all other copyright header intact, only adding the
SPDX ident. As far as possible this commit also merges multiple
Data61 copyright statements/headers into one for consistency.

Remove platform IPC buffer register.

This removes the assumption that each platform sotres the IPC buffer
address in a platform-specific register. The IPC buffer address is
instead stored in a thread-local variable in libsel4 which must be
initialised by the runtime.

Remove symlinked libsel4 files from include dir

These files can be included normally using libsel4 include paths. This
removes situations where the same file is available under different
include paths due to symlinking into different directory structures.

style: consistently attach return type

Add attach-return-type to astyle

arm: remove assumption that CONFIG_IPC_BUF_* must be set

Previously arm code assumed that either CONFIG_IPC_BUF_TPIDRURW or
CONFIG_IPC_BUF_GLOBALS_FRAME needed to be set. Given that neither of
these options are required for aarch64, remove this assumption and only
guard code with #ifdefs are required.

aarch64: Use tpidrro_el0 for IPC buffer instead of tpidr_el0

Changing the register used for the IPC buffer is useful as the standard TLS model for
aarch64 is to use tpidr_el0 for the thread pointer, which we are presently using
for the IPC buffer. This therefore paves the way for implementing proper TLS support
on aarch64.

Since we are not using tpidr_el0 for the IPC buffer we need to save/restore (or at
least clear) this register on thread switch to prevent it being a user channel. Saving
and restoring of it is achieved by ensuring CONFIG_IPC_BUF_TPIDRURW is not set, which
as we are no longer using this strategy this will be the case. To that end as aarch64
only has one IPC buffer strategy this commit makes the choice of IPC buffer strategy
dependeont on aarch32.

SMP: Introduce ENABLE_SMP_SUPPORT

- Make it more readable and less confusing compared to the 'CONFIG_MAX_NUM_NODES > 1' check

SELFOUR-806: aarch32 - Implement lazy FP save/restore

This commit implements lazy FP save/restore mechanism, required for user threads
when they use the FPU. The following caveats take place:

* Only support synchronous exceptions. No support for asynchronous ones.
* VFP opcodes are used instead of normal instructions to discard compiler warnings/errors.
* Support is limited to specific ARM subarchitectures we support and tested this commit on.
* Disable the FPU by default if users are not using it to avoid channels.
* FPU support is not verified yet.
* Will not work properly if using a VM that's running besides other VMs/threads that are using the FPU.

SELFOUR-746: IPI Handler for ARM

Abstract setting ipc buffer register into arch fn

SMP: Move/rename migrateTCB() arch tcb.c

Split fault types into arch/generic

Prior to this commit faults were separate
per architecture. This commit extracts the common
fault types and introduces arch specific faults,
reducing code duplication across architectures.

SELFOUR-499: X86, ARM: Add userspace invocations for hardware debugging

This commit implements the body of SELFOUR-499. The API exposes the x86 DR0-7
and ARM coprocessor 14 features to userspace by virtualizing them as context-
switched registers in the TCB. Implemented as TCB invocations. This feature is
only built when CONFIG_HARDWARE_DEBUG_API is selected.

* Add low-level support routines for setting, unsetting, getting, enabling
and disabling breakpoints.
* Add support for single-stepping as well.
^ Single-stepping is not supported on ARMv6 since the hardware
doesn't have support.
^ ARM implements single-stepping as instruction breakpoints
configured to fault on every instruction -- this is achieved through
the "mismatch" mode, which is only supported from ARMv7 onwards.
* Also support explicit software break requests, a la "BKPT" and "INT $3".

* New invocations:
* seL4_TCB_SetBreakpoint().
* seL4_TCB_GetBreakpoint().
* seL4_TCB_UnsetBreakpoint().
* seL4_TCB_ConfigureSingleStepping().
* New constants:
^ Event types:
^ seL4_InstructionBreakpoint.
^ seL4_DataBreakpoint.
^ seL4_SoftwareBreakRequest.
^ Access types:
^ seL4_BreakOnRead.
^ seL4_BreakOnWrite.
^ seL4_BreakOnReadWrite.
^ Exports:
^ seL4_NumHWBreakpoints.
^ seL4_NumExclusiveBreakpoints.
^ seL4_NumExclusiveWatchpoints.
^ seL4_NumDualFunctionMonitors.
^ seL4_FirstBreakpoint.
^ seL4_FirstWatchpoint.
^ seL4_FirstDualFunctionMonitor.

See documentation in the seL4 API manual.

trivial: remove duplicated setMRs_syscall_error

arm-hyp: Minor cleanups

Cleanup some small licensing, whitespace and configuration details

arm_hyp: rm ARM_HYP ifdefs; func inline assembly

vcpu.c:
encapsulate inline assembly into inline functions that added to
device_pl2.h file.

other files:
replace #ifdef ARM_HYP with config_set(ARM_HYP)

arm_hyp: rm ARM_HYP ifdefs; func inline assembly

vcpu.c:
encapsulate inline assembly into inline functions that added to
device_pl2.h file.

other files:
replace #ifdef ARM_HYP with config_set(ARM_HYP)

Change additional int->word_t due to interraction with the C parser to ease verification

unsigned int -> word_t

ARM HYP: Trap SMC

Report IPA for restart address in vm faults

Recommit of arm_hyp branch on release snapshot

Release snapshot