46: Assure address of PC at startup. r=Disasm a=elfmimi

PR created upon @Disasm 's request. 

Closes: #44

Need update of library files after merging.

Co-authored-by: Ein Terakawa <applause@elfmimi.jp>
Co-authored-by: Vadim Kaushan <admin@disasm.info>

43: Place abort in the .text section r=Disasm a=istankovic

Don't clutter the .init section needlessly.

Co-authored-by: Ivan Stankovic <istankovic@users.noreply.github.com>
Co-authored-by: Ivan Stankovic <istankovic@posteo.net>

Don't clutter the .init section needlessly.

41: Make linker script compatible with GNU linker. r=Disasm a=pftbest

Assigning to the dot inside the section declaration is section
relative, not absolute.

Co-authored-by: Vadzim Dambrouski <pftbest@gmail.com>

Assigning to the dot inside the section declaration is section
relative, not absolute.

40: Simple typo fix r=almindor a=iankronquist

Just poking around and noticed this. Hope it's not too much trouble.

Co-authored-by: Ian Kronquist <iankronquist@gmail.com>

38: link.x: Add .sdata2 sections r=Disasm a=laanwj

Clang doesn't seem to generate these, but GCC (8.3.0 at least) does. I'm trying to link secp256k1, which is a C library, to my Rust code so the linker script needs to include these sections too.

Co-authored-by: Wladimir J. van der Laan <laanwj@gmail.com>

Clang doesn't seem to generate these, but GCC does. I'm trying to
link secp256k1, which is a C library, to my Rust code so the linker
script needs to include these sections too.

37: Fix _start_trap save/restore sequences r=laanwj a=Disasm



Co-authored-by: Vadim Kaushan <admin@disasm.info>

36: Fix linker script r=laanwj a=Disasm

This PR fixes
* section alignment issues
* section flags (now both `.heap` and `.stack` are `NOBITS`)
* wrong offsets with overridden `_stext`

Co-authored-by: Vadim Kaushan <admin@disasm.info>

35: Add .sbss section to linker script r=Disasm a=laanwj

Rust nightly has started generating this section for RISC-V executables, place it at the start of the bss area.

```
  = note: rust-lld: error: no memory region specified for section '.sbss'
```

I think this is correct, looking at other uses of the section, though I could find no definitive documentation for this.

Co-authored-by: Wladimir J. van der Laan <laanwj@gmail.com>

Rust nightly has started generating this section for RISC-V executables,
place it at the start of the bss area.

31: New linker script and multi-core support r=laanwj a=Disasm

* Linker script was reworked. Now it uses region aliases to relocate sections. This approach makes it possible to build firmware for both FLASH+RAM and RAM-only targets. Memory definitions now supposed to be present in their corresponding crates (e.g. RAM definition in PAC crate, FLASH definition in board support crate).
* Multi-core support was introduced. Cores are parked with `_mp_hook` function and then awakened in platform-dependent way.
* Documentation was updated to reflect new features.
* New crate version: 0.6.0

Depends on: https://github.com/rust-embedded/riscv/pull/28
Closes: https://github.com/rust-embedded/riscv-rt/issues/26



Co-authored-by: Vadim Kaushan <admin@disasm.info>

32: Rename RISCV to RISC-V r=laanwj a=Disasm

The same as here: https://github.com/rust-embedded/riscv/pull/25



Co-authored-by: Vadim Kaushan <admin@disasm.info>