This commit introduces zephyr_linker CMake functions for creation of
linker scripts.

The linker functions supports the following features:
- Configuration of memory sections
- Configuration of memory groups
- Creation of output sections
- Configuration of input section the should go into output section and
  how those should be treated, such as sorting, keep, priority.
- Defining linker symbols
- Specifying Kernel VMA to support virtual linking on x86

Overview of functions and macros introduce with this commit:
- pow2round
- zephyr_linker
- zephyr_linker_memory
- zephyr_linker_memory_ifdef
- zephyr_linker_group
- zephyr_linker_section
- zephyr_linker_section_ifdef
- zephyr_iterable_section
- zephyr_linker_section_obj_level
- zephyr_linker_section_configure
- zephyr_linker_symbol
- zephyr_linker_property_append

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

This commit introduces zephyr_linker_dts CMake functions for creation of
linker scripts based on devicetree nodes.

The linker devicetree functions supports the following features:
- Configuration of memory sections based on devicetree nodes

Overview of functions introduced with this commit:
- zephyr_linker_dts_memory

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

Converted existing ld script templates into CMake files.

This commit takes the common-ram.ld, common-rom.ld, debug-sections.ld,
and thread-local-storage.ld and creates corresponding CMake files for
the linker script generator.

The CMake files uses the new Zephyr CMake functions:
- zephyr_linker_section()
- zephyr_linker_section_configure()
- zephyr_linker_section_obj_level()

to generate the same linker result as the existing C preprocessor based
scheme.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

This commit specifies the intList section in the IDT_LIST region in the
arch/common CMakeLists.txt file.

It uses zephyr_linker_section to setup the intList section for first
pass linker file and configures the section to hold irq_info and
intList input section.

For second pass linker file, the irq_info and intList input sections are
placed in the /DISCARD/ section.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

This is the initial version of a Zephyr CMake linker file for the arm
architecture.

This file defines memory regions, groups, linker sections and symbols
for the arm architecture.

It also sources the common common-ram.cmake, common-rom.cmake,
debug-sections,cmake, and thread-local-storage.cmake.

It configure sections for SoC families using zephyr_linker_sources()
functions:
- nxp_imx

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

This commit add devicetree memory regions added to arm/linker.cmake.

The following memory regions are now added to the generated linker
script and scatter file if they exists in the devicetree.
- chosen:    zephyr,itcm
- chosen:    zephyr,dtcm
- nodelabel: ti_ccfg_partition
- nodelabel: sram1
- nodelabel: sram2
- nodelabel: sram3
- nodelabel: sram4
- nodelabel: sdram1
- nodelabel: sdram2
- nodelabel: backup_sram

Also support for the itcm and dtcm section and their placement in
corresponding memory regions has been added.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

Adding intial version of linker_script_common.cmake.

This script parses memory regions, groups, sections, settings, and
symbols defined in the Zephyr CMake build system.

The linker script creates objects for each type above and groups
sections, symbols, and groups together based on their configuration.

This creates a hierarchy which the `<linker>_script.cmake`
implementations can then use during linker script generation.

linker_script_common.cmake also provides stubs for <type>_to_string()
functions which are used when generating the output script.

Each specific `<linker>_script.cmake` must implement those to_string()
functions to create the final linker script.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

Adding intial version of ld_script.cmake.

This script can generate ld linker script from the Zephyr CMake linker
functions.

This script is called by the build system and all linker settings, such
as memory regions, groups, output sections, linker symbols defined with
Zephyr CMake linker functions are passed to this script in order to
generate an ld linker script.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

A "Linker script" choice group has been added to the linker options
menu.

The existing HAVE_CUSTOM_LINKER_SCRIPT config has been relocated inside
the linker script menu.

Two new entries has been created:
- LD template, for using the old ld template files together with the C
  pre-processor to create the final linker script.
- CMake linker generator, used for ARMClang / armlink toolchain.
  The CMake linker generator is also supported for LD linker scripts
  for the ARM architecture.

In CMake, the file cmake/linker/ld/target.cmake has been updated to
support the CMake LD linker generator.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

The armclang.h includes the toolchain/llvm.h header.

Also it redifines the __GENERIC_SECTION and Z_GENERIC_SECTION so that
they includes the `used` attribute which is needed by armlink.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

Initial bintools support for elfconvert
- hex, srec, bin conversion
- strip
- gap fill

Initial bintools support for readelf
Initial bintools support for disaasembly

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

This is the initial support for the armclang compiler together with the
armlink linker.

Introduced in this commit:
- armclang compiler support
- armlink linker support
- armlink scatter file generator for scatter loading
- dual pass linker script generation

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

When using ARMClang linker and scatter files (armlink) then all
libraries are linked as object libraries using `$<TARGET_OBJECTS:lib>`.

CMake version 3.20 only has limited support for such linking:
> Referencing $<TARGET_OBJECTS> in target_link_libraries calls worked
> in versions of CMake prior to 3.21 for some cases, but was not fully
> supported.

One of those cases that do not work is Unix Makefiles generators.

As only Ninja is currently verified to work, this commit will check the
CMake version in use and the generator, and if CMake version <=3.21 is
used with non-Ninja generator then an error is raised informing user
to either use Ninja generator or update CMake.

As the Ninja generator has been confirmed to work as expected, then that
generator is accepted with CMake 3.20 and older.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

The default armlink signature uses `--list=<TARGET_BASE>.map`, but in
Zephyr we uses a different name for the map file, therefore we need to
specify a custom link executable signature.

This is done in the linker specific flags file:
cmake/linker/armlink/linker_flags.cmake

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

This commit introduces armlink steering file.

A steering file in armlink allows Zephyr to keep using existing linker
symbols defined in ld scripts and used throughout the code tree.

The steering file is generated at build time in order to resolve Zephyr
linker symbols to their corresponding armlink symbols.

As example, Zephyr defines __ramfunc_start which corresponds to the
armlink auto defined Image$$ramfunc$$Base symbol.

Or __init_PRE_KERNEL_1_start which corresponds to Image$$init_0$$Base.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

Support for ARM Compiler C library.

This commit add support for the ARM Compiler C libary in:
- Kconfig
- libc/armstdc

A new Kconfig symbol is added to allow a toolchain to specify if they
support linking with the minimal C library.
Also the CMake variable `TOOLCHAIN_HAS_NEWLIB` is exported to Kconfig
so that CONFIG_NEWLIB_LIBS can only be enabled if the toolchain has
newlib.

The armclang toolchain selects the CMake scatter file generator and
disables support for the LD linker template which is not supported by
armlink.

For the ARM Compiler C library, a corresponding lib/libc/armstc/ folder
with a minimal implementation to work with the ARM Compiler C library
is added.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

The stub file threading_weak.c has been added containing weak stub
implementation of threading related kernel functions.

The file is needed for armlink.

When linking with armlink the linker will resolve undefined symbols for
all undefined functions even if those functions the reference the
undefined symbol is never actually called.

This file provides weak stub implementations that are compiled when
CONFIG_MULTITHREADING=n to ensure proper linking.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

This commit adds an additional test case for several kernel test suites
to ensure that the linker script generator is working correctly for a
subset of the Zephyr test suites.

The ensures that the basic functionality of the linker script generator
is working while still keep the performance impact on CI at a minimal
level.

Using the kernel tests is a trade-off between testing coverage of the
linker script generator and the time it takes to complete CI.

The kernel tests is considered to have the broadest coverage of various
features important for the generated linker script.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>