- nasm doesn't support aarch64

- rename x86 workflow

Signed-off-by: Jonathan Schwender <schwenderjonathan@gmail.com>

Remove `;` to remove warning

Signed-off-by: Jonathan Schwender <schwenderjonathan@gmail.com>

If the elf header doesn't contain an entrypoint (the value is zero), then well just jump to the start of the elf file, which should be avoided.
Thus we add an assertion to check for this.

Signed-off-by: Jonathan Schwender <schwenderjonathan@gmail.com>

- Explicitly setting each bit and putting the documentation next to it makes this more readable in my opinion.
- Some bits that are set did not have any documentation here before.
  A Todo was added to lookup the source of this documentation and add the missing information

Convert existing llvm_asm! to new asm! format.
I'm no expert in Assembly, so I'm not super confident I got everything right.
Should definitely be carefully reviewed.

- Only initialize CPU 0 and spin on other CPUs (based on https://github.com/rust-embedded/rust-raspberrypi-OS-tutorials/)
- Adjust physical start address of RAM to correct value for raspi3 (again based on the raspberry tutorial)
- Add feature to map write_char() to use a special address for usage with qemu. The aarch64 solution doesn't seem to work on qemu. Didn't look to closely though.
 The feature is enabled by default for make arch=aarch64 for now. A toggle is future work

- build image from scratch

- explicit activation of optimized core functions (e.g. memcpy) isn't longer required

* Use new toolchain TOML format
  This allows us to specify a specific version and needed components that rustup can then automatically install.

add support of relocatable unikernels and aarch64

- redesign of the HermitCore bootloader
- add basic aarch64 support
- switch to relocatable unikernels to relize (later) ASLR
- using of the crate goblin to parse the ELF binaries

Fix loader. Previously strongly dependent on the input ELF's layout.

Cleanup

Kernel had to lie non-overlapping with its final position, but still
inside the ELF since no additional memory was marked writable.

- disable temporary OS ABI checks

Since the call doesn't return this doesn't actually fix any error, but syntactically this is more correct.

- afterwards, we copy it back to the suggest virtual address
- unneeded, because we have already position independent code