update CI for build-doc

.github/workflows/build-doc.yml

@@ -0,0 +1,25 @@
+name: Build Rust Doc
+
+on: [push]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build-doc:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Build doc
+        run: |
+          rustup target add riscv64gc-unknown-none-elf
+          rustup component add llvm-tools-preview
+          rustup component add rust-src
+          cd os
+          cargo doc --no-deps --verbose
+      - name: Deploy to Github Pages
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./os/target/riscv64gc-unknown-none-elf/doc
+          destination_dir: ${{ github.ref_name }}

os/src/sbi.rs

@@ -27,14 +27,17 @@ fn sbi_call(which: usize, arg0: usize, arg1: usize, arg2: usize) -> usize {
     ret
 }
 
+/// use sbi call to putchar in console (qemu uart handler)
 pub fn console_putchar(c: usize) {
     sbi_call(SBI_CONSOLE_PUTCHAR, c, 0, 0);
 }
 
+/// use sbi call to getchar from console (qemu uart handler)
 pub fn console_getchar() -> usize {
     sbi_call(SBI_CONSOLE_GETCHAR, 0, 0, 0)
 }
 
+/// use sbi call to shutdown the kernel
 pub fn shutdown() -> ! {
     sbi_call(SBI_SHUTDOWN, 0, 0, 0);
     panic!("It should shutdown!");