Use gcc to pre-process mipsel assembly

Signed-off-by: Harry Chen <i@harrychen.xyz>

.gitignore

@@ -1,7 +1,7 @@
 build
 target
 /kernel/src/arch/x86_64/interrupt/vector.asm
-/kernel/src/arch/*/boot/dtb.S
+*.gen.s
 *.dtb
 
 Cargo.lock

kernel/Makefile

@@ -317,6 +317,9 @@ else ifeq ($(arch), riscv64)
 else ifeq ($(arch), aarch64)
 	@cargo xbuild $(build_args)
 else ifeq ($(arch), mipsel)
+	@for file in context entry trap ; do \
+	    $(cc) -E src/arch/$(arch)/boot/$${file}.S -o src/arch/$(arch)/boot/$${file}.gen.s ; \
+	done
 	@cargo xbuild $(build_args)
 endif
 

kernel/build.rs

@@ -60,13 +60,12 @@ fn gen_dtb_asm(arch: &String, _board: &String) -> Result<()> {
         panic!("DTB `{}` not found", dtb)
     }
 
-	let mut f = File::create(format!("src/arch/{}/boot/dtb.S", arch)).unwrap();
+	let mut f = File::create(format!("src/arch/{}/boot/dtb.gen.s", arch)).unwrap();
 
     println!("cargo:rerun-if-changed={}", dtb);
     println!("cargo:rerun-if-env-changed=DTB");
 
 	writeln!(f, "# generated by build.rs - do not edit")?;
-	writeln!(f, ".intel_syntax noprefix")?;
 	write!(f, r#"
     .section .dtb,"a"
     .align 12

kernel/src/arch/mipsel/boot/entry.S

@@ -11,14 +11,15 @@ _start:
 
     # set ebase
     la    t0, trap_entry
-    mfc0  t1, 15 # C0_EBASE
+    mfc0  t1, $15 # C0_EBASE
     or    t1, t1, t0
-    mtc0  t1, 15
+    mtc0  t1, $15
 
     # exit bootstrap mode
-    mfc0  t0, 12 # C0_STATUS
-    andi  t0, t0, 0xFFBFFFFF # set BEV (bit 22) to 0
-    mtc0  t0, 12
+    mfc0  t0, $12 # C0_STATUS
+    li    t1, 0xFFBFFFFF # set BEV (bit 22) to 0
+    and   t0, t0, t1 
+    mtc0  t0, $12
 
     # directly jump to main function
     b rust_main

kernel/src/arch/mipsel/context.rs

@@ -159,7 +159,7 @@ impl Context {
     #[naked]
     #[inline(never)]
     pub unsafe extern fn switch(&mut self, _target: &mut Self) {
-        asm!(include_str!("boot/context.S"));
+        asm!(include_str!("boot/context.gen.s"));
     }
 
     /// Constructs a null Context for the current running thread.

kernel/src/arch/mipsel/mod.rs

@@ -74,6 +74,6 @@ fn others_main() -> ! {
 
 const BOOT_CPU_ID: u32 = 0;
 
-global_asm!(include_str!("boot/entry.S"));
-global_asm!(include_str!("boot/trap.S"));
-global_asm!(include_str!("boot/dtb.S"));
+global_asm!(include_str!("boot/entry.gen.s"));
+global_asm!(include_str!("boot/trap.gen.s"));
+global_asm!(include_str!("boot/dtb.gen.s"));