move hard link user asm to Rust

kernel/build.rs

@@ -1,12 +1,12 @@
 extern crate cc;
 
 use std::fs::File;
-use std::path::Path;
 use std::io::{Result, Write};
 
 fn main() {
 	println!("cargo:rerun-if-env-changed=LOG");
 	println!("cargo:rerun-if-env-changed=BOARD");
+	println!("cargo:rerun-if-env-changed=SFSIMG");
 
 	let arch: String = std::env::var("ARCH").unwrap();
 	let board: String = std::env::var("BOARD").unwrap();
@@ -15,31 +15,14 @@ fn main() {
 			gen_vector_asm().unwrap();
 		}
 		"riscv32" => {
-			if let Ok(file_path) = gen_sfsimg_asm() {
-				cc::Build::new()
-					.file(&file_path)
-					.flag("-march=rv32imac")
-					.flag("-mabi=ilp32")
-					.compile("sfsimg");
-			}
 		}
 		"riscv64" => {
-			if let Ok(file_path) = gen_sfsimg_asm() {
-				cc::Build::new()
-					.file(&file_path)
-					.flag("-march=rv64imac")
-					.flag("-mabi=lp64")
-					.compile("sfsimg");
-			}
 			if board == "k210" {
 				println!("cargo:rustc-link-search=native={}", "../tools/k210");
 				println!("cargo:rustc-link-lib=static=kendryte");
 			}
 		}
 		"aarch64" => {
-			if let Ok(file_path) = gen_sfsimg_asm() {
-				cc::Build::new().file(&file_path).compile("sfsimg");
-			}
 		}
 		_ => panic!("Unknown arch {}", arch),
 	}
@@ -68,27 +51,3 @@ fn gen_vector_asm() -> Result<()> {
 	}
 	Ok(())
 }
-
-fn gen_sfsimg_asm() -> Result<std::path::PathBuf> {
-	let out_dir = std::env::var("OUT_DIR").unwrap();
-	let sfsimg = std::env::var("SFSIMG").unwrap();
-
-	let file_path = Path::new(&out_dir).join("sfsimg.S");
-	let mut f = File::create(&file_path).unwrap();
-
-	write!(f, "# generated by build.rs - do not edit")?;
-	write!(f, r#"
-	.section .rodata
-	.align 12
-	.global _user_img_start
-	.global _user_img_end
-_user_img_start:
-    .incbin "{}"
-_user_img_end:
-"#, sfsimg)?;
-
-	println!("cargo:rerun-if-changed={}", sfsimg);
-	println!("cargo:rerun-if-env-changed=SFSIMG");
-
-	Ok(file_path)
-}

kernel/src/fs/mod.rs

@@ -15,6 +15,17 @@ mod stdio;
 mod device;
 mod pipe;
 
+/// Hard link user programs
+#[cfg(feature = "link_user")]
+global_asm!(concat!(r#"
+	.section .data
+	.global _user_img_start
+	.global _user_img_end
+_user_img_start:
+    .incbin ""#, env!("SFSIMG"), r#""
+_user_img_end:
+"#));
+
 lazy_static! {
     /// The root of file system
     pub static ref ROOT_INODE: Arc<INode> = {