1. aCore - 配置Rust Project 和第一次建置

2020-05-10

環境配置懶人包

在開發前, 我們配一下Rust 環境。會用Rustup 的話, 就不多解釋下面的命令了。如果不了解的話Rustup 和Cargo 自身也帶備說明。
所以, 我直接來個 環境配置懶人包:

$ rustup toolchain install nightly #安裝rust nightly 環境
$ rustup component add rls --toolchain nightly #Nightly RLS
$ cargo new --bin aCore 
$ cargo install cargo-xbuild #xbuild 可以建置 core, compiler_builtins 和 alloc
$ rustup component add rust-src #Rust的原始碼
$ rustup override set nightly #預設nightly

查看一下自己的Target 設定:
rustc +nightly -Z unstable-options --print target-spec-json

會看到類似:

{
  "arch": "x86_64",
  "cpu": "x86-64",
  "data-layout": "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128",
  "dynamic-linking": true,
  "env": "gnu",
  "executables": true,
  "has-elf-tls": true,
  "has-rpath": true,
  "is-builtin": true,
  "linker-flavor": "gcc",
  "linker-is-gnu": true,
  "llvm-target": "x86_64-unknown-linux-gnu",
  "max-atomic-width": 64,
  "os": "linux",
  "position-independent-executables": true,
  "pre-link-args": {
    "gcc": [
      "-Wl,--as-needed",
      "-Wl,-z,noexecstack",
      "-m64"
    ]
  },
  "relro-level": "full",
  "stack-probes": true,
  "target-c-int-width": "32",
  "target-endian": "little",
  "target-family": "unix",
  "target-pointer-width": "64",
  "vendor": "unknown"
}

有關細項的解釋, 可查看: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_target/spec/struct.Target.html
可以留意一下前幾項。我們會用到那邊的配置。

建立 x86_64-aCore.json

{
    "llvm-target": "x86_64-unknown-none",
    "data-layout": "e-m:e-i64:64-f80:128-n8:16:32:64-S128",
    "arch": "x86_64",
    "target-endian": "little",
    "target-pointer-width": "64",
    "target-c-int-width": "32",
    "os": "none",
    "executables": true,
    "linker-flavor": "ld.lld",
    "linker": "rust-lld",
    "panic-strategy": "abort",
    "disable-redzone": true,
    "features": "-mmx,-sse,+soft-float"
}

data-layout

這個項目是LLVM用來設定資料在記憶體中儲存的方式，
每個部份用減號 - 來分隔。
而分隔項可以查看:
http://llvm.org/docs/LangRef.html#data-layout

其他可以隨便修改試試看, 但 "features": "-mmx,-sse,+soft-float" 是要留下的。
否則的話 opcode 不正確會引起 CPU 的Triple Fault, 嚴重的會把Host 也同時掛掉 ,
所以我們日後有機會再面對MMX 和SSE 吧。

修改

建立或修改你的main.rs

#![no_std]
#![no_main]

use core::panic::PanicInfo;

#[panic_handler]
fn panic(_info: &PanicInfo) -> ! {
    loop {}
}

#[no_mangle]
pub extern fn _start() -> ! {
    loop {}
}

修改Cargo.toml

[package]
name = "aCore"
version = "0.1.0"
authors = ["Abby <[email protected]>"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]

[profile.dev]
panic = "abort"

[profile.release]
panic = "abort"

建置:
cargo xbuild --target x86_64-aCore.json