replacing all ifndef with pargma once

All the kernel header files now use pargma once rather than the ifndef,
as the pre-processed C files do not change while header files
are protected with pargma once. This will also solve any naming issues
caused by ifndef.

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.

ARM: Add support to flush L1 caches

Extend the existing seL4_BenchmarkFlushCaches without modifing the usage
of it. Will be used in sel4bench to measure the cold cache performance.

Add syscall for setting the current TLS register.

Some platforms and configurations do not allow user code to change the
value of the register used for TLS. On these architectures a syscall can
be used to allow the kernel to update the register on their behalf.

This does not immediately update the value in the user context on many
configurations as the values are only stored in the user context on a
context switch.

Added IRQ routing to specific core for ARM

Add a new syscall, `seL4_IRQControl_GetTriggerCore`, to get a IRQHandler
with specific target core(s) and trigger method. Only available in SMP
mode.

boot: consolidate init_freemem

init_freemem sets up available regions of memory for the hardware that
seL4 is booting on. Previously this function was duplicated across
architectures, with minor duplication.

This change provides a top-level init_freemem suitable for all
architectures.

- arm/riscv: change get_avail_p_reg to return whole p_reg array
- update all architectures to use new init_freemem.
- wrap init_freemem calls with arch_init_freemem for each arch, where
arch_init_freemem sets up the available and reserved regions of memory
which are passed to init_freemem.

style: consistently align pointer with name

Run astyle with align-pointer=name

arm: Rename plat_cleanInvalidateCache

Rename plat_cleanInvalidateCache to plat_cleanInvalidateL2Cache to
indicate that it is a L2 cache maintenance operation only.

SELFOUR-1491: verification updates

- renamed an architecture label so that it begins with ARM.
- changed setIRQTrigger so that it takes a boolean value instead of an int.
- Arch_decodeIRQControlInvocation converts the second argument (trigger)
to a boolean immediately.

SELFOUR-1491: add seL4_IRQCOntrol_GetTrigger

Add a new invocation which allows an irq handler capability to be
obtained with a specific trigger method (edge or level). Obtaining
this capability modifies the GIC state.

SMP: Introduce ENABLE_SMP_SUPPORT

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

ARM/IRQ: add a function to initialise local IRQ controller for CPUs

Similar to initIRQController(), cpu_initLocalIRQController() has to
be implemented for each platform. For those that are gonna support
SMP, it should be implemented proprely (if required), otherwise
it can be stubbed for single core implementations.

Replace Arch_handleInterrupt with Arch_finaliseInterrupt

x86: Handle pending interrupt before scheduling thread in handleSyscall

In handleSyscall the current thread may be preempted to handle a pending interrupt.
With kernel mode interrupts in x86 this handling was delayed until we were about
to switch back to user mode. This change unifies the handling with ARM, where the
interrupt is handled prior to calling the thread scheduler.

SMP: guard arch_pause() with #ifdef for verification purposes

[STYLE_FIX]

SMP: move lock.h to architecture-independent include/smp

s/__sync_lock_test_and_set/__atomic_exchange_n in lock.h

Remove many MODIFIES annotations.

These are redundant for any function which the C-to-Isabelle parser
actually analyses, which is now the vast majority of functions.

Fix arm builds broken in 44ed6adb6

SELFOUR-519: remove duplicated constants

* rename physBaseMapping to BASE_OFFSET
* because physBaseMapping was only used explicity in a few places
* move duplicated arm definions up a level
- PPTR_TOP
- PADDR_TOP
- BASE_OFFSET

Refactor duplicated code in hardware.h

One copy to rule them all.

arm-hyp/tk1: fix bugs found during testing

Rearranging headers for aarch32 to 32/mode/*

unsigned int -> word_t

Rename uint32_t -> word_t in any relevant places

arm: Rearrange context switching code to make fastpath and regular code not duplicate functionality

ARM: Add config options for exporting PMU and ARM generic timer physical count registers to PL0

DONT_TRANSLATE more inline asm functions.

The c-parser can now parse these functions, but it does it by
discarding the inline ASM block, creating a misleading and likely
malformed function body. It is better to not translate these
with a DONT_TRANSLATE comment.

This change has been made for the current verification platform
only, and should probably be extended to any other verification
targets as necessary.

Recommit of arm_hyp branch on release snapshot

arm: Add work around for errata on some Cortex-A15 boards and move errata checking to C code

Release snapshot