- for arm generic timer platforms, we remove resetTimer ->
resetGenericTimer indirection and simply include generic_timer.h
- this reduces boiler plate for platforms that share timer drivers, as
  they simply include the one header
- there is far more timer code in the RT kernel, which motivates this
change

This prepares to inline the resetTimer definition from generic_timer.h
without creating a mess of circular includes

This prepares for inlinining the generic timer in header files, which will reduce the
redundancy for all platforms that use it.

Since mct.c shared code with the generic timer, both could not define a
resetTimer function. This commit splits the logic and definitions used
by exynos4 and exynos4* into common definitions in mct.h, with the
unique code for both in hardware.c

The RT kernel needs this value accessible to common functions.

- remove a lot of redundancy
- define TIMER_CLOCK_HZ for each platform (rather than inconsistenly
named variables with inconsist units)
- use the common calculation of TIMER_RELOAD

- make them consistent: struct, type and global vars
- typedef the struct definition as volatile
- separate struct, typedef and variable definition
- always cast the pointer as the timer type

Only platforms that use it should include the code

initTimer does not exist on x86

Instead of switching to the thread contained in `ksSchedulerAction` on a `schedule` we
instead decide between the 'candidate' contained in `ksSchedulerAction`, the current thread
or potentially neither if the candidate is deemed invalid and the current thread is blocked.

A consequence of this change is that it is no longer meaningful to have a distinction between
`switchIfRequiredTo` and `attemptSwitchTo`. Now both these cases simply identify a candidate,
which may or may not be picked in `schedule`. Part of the distinction of `switchIfRequiredTo`
was to not avoid switching if possible when performing notifications. This is now handled by
prefering the current thread over the candidate if the current thread has not blocked.

This change is largely semantic preserving overall, with the exception of non-blocking
synchronous sends now acting like notifications and also preferring to resume running the
current thread.

The motivation for this change was to make it much easier for verification to show
correspondence between the fastpath changes introduced in the previous commit and the
slowpath scheduler.

Changes the fastpath to check if the destination thread is the highest priority thread
in the scheduler, even if it is lower priority than the calling thread.

Provides better cache performance for high priority threads

Moves the logic from chooseThread into a dedicated helper function

This corrects the calculation of the L2 bitmap size to correctly handle cases where the
requested num priorities is not a clean multiple of the wordBits

Implement configs which export the physical and or virtual generic timer
count register to use level.

This brings it inline with armv8 (aarch32) and armv7.

- add timestamp(), timestamp_t for aarch64
- implement CONFIG_EXPORT_PMU_USER

Use SYSTEM_READ_WORD, each platform defines the CCNT constant.

it was causing circular references in files where it is defined and
hardware macros are also used.

DANGEROUS_CODE_INJECTION does not work on the Hikey due to the current
state of the vspace implementation.

The GetStatusBits invocation is only implemented on ia32. Adding the condition to the
XML list prevents the invocation from being in the list of invocations on x86_64, when
it has no implementation.

Previously both aarch32 and aarch64 duplicated common
generic timer code. Unify them in include/arch/arm/machine/timer.h

This check checks the TIMER_RELOAD fits in the wordsize.
Use UINTPTR_MAX instead of 0xffffffff so the check can be moved
to mode agnostic code.

This brings the aarch64 generic timer into exactly the same code as
the aarch32 generic timer.

This commit generalises 32 and 64 bit configuration for arm: 32bit uses
coprocessor access through mrc/mcr, 64bit system configuration through
msr,mrs

- SYSTEM_READ|WRITE_WORD: read or write configuration word
- SYSTEM_READ|WRITE_64  : read or write 64bits of configuration

- UINTPTR_MAX
- UINT64_MAX
- UINT32_MAX
- INT64_MAX
- INT32_MAX

TOPLEVELTYPES is not intended to be configurable by the user, rather is a reflection
on the types defined by the source. This changes the TOPLEVELTYPES argument to be
a property, allowing it to be constructed as a generator expression when generating
BF files. By being a property, and not something like a global property, it removes
the need to ensure that additions to TOPLEVELTYPES are done prior to any bitfield
target definitions.

Defines an empty custom target whose purpose is to hold properties and configuration
data that can be retrieved using generator expressions in the build phase.

Uses the COMMAND_EXPAND_LISTS flag to allow for generator expressions in parameters
to GenBFCommand. As lists are now being expanded the 'args' variable must also be
quoted.

`Arch_checkIRQ` already prints an error message in the case of x86. Printing the additional
error message is both unnecessary, confusing as the message makes no sense on x86. As the
error does make sense on ARM this commit moves the message to the arm `Arch_checkIRQ`

These functions are referenced from code that is not guarded by an #ifdef CONFIG_IRQ_PIC,
which was only working due to the optimizer being able to elide the calls prior to
linking.