global: prototype transfer vectors

Add a prototype transfer vector into `global`.

Signed-off-by: Dan Cross <[email protected]>

Author: Dan Cross

Cargo.lock

@@ -15,3 +15,4 @@ edition = "2021"
 [dependencies]
 arch = { package = "x86_64", path = "../x86_64" }
 hypatia = { path = "../hypatia" }
+uart = { path = "../uart" }

global/Cargo.toml

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021  The Hypatia Authors
+ * Copyright 2023  The Hypatia Authors
  * All rights reserved
  *
  * Use of this source code is governed by an MIT-style
@@ -9,9 +9,17 @@
 
 ENTRY(init)
 
+EXTERN(xferv);
+
 SECTIONS {
 	. = 0xFFFFFC0000000000;
 
+	.xferv . :
+	{
+		KEEP(*(.xferv*))
+	}
+	. = ALIGN(4096);
+
 	.text . :
 	{
 		*(.text*)

global/src/link.ld

@@ -1,29 +1,24 @@
-// Copyright 2021  The Hypatia Authors
+// Copyright 2023  The Hypatia Authors
 // All rights reserved
 //
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+#![feature(naked_functions)]
 #![feature(strict_provenance)]
 #![cfg_attr(not(test), no_main)]
 #![cfg_attr(not(test), no_std)]
 #![forbid(absolute_paths_not_starting_with_crate)]
 #![forbid(elided_lifetimes_in_paths)]
 #![forbid(unsafe_op_in_unsafe_fn)]
 
-use arch::Page4K;
-
-/// Returns a static reference to the global zero page.
-pub fn zero_page() -> &'static Page4K {
-    const ZERO_PAGE: Page4K = Page4K::new();
-    &ZERO_PAGE
-}
+mod x86_64;
 
 /// Initialize the system.
 #[no_mangle]
 pub extern "C" fn init() {
-    zero_page();
+    uart::panic_println!("Hello from global");
 }
 
 hypatia::runtime!();

global/src/main.rs

@@ -0,0 +1,8 @@
+// Copyright 2023  The Hypatia Authors
+// All rights reserved
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+mod xferv;

global/src/x86_64/mod.rs

@@ -0,0 +1,31 @@
+// Copyright 2023  The Hypatia Authors
+// All rights reserved
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+use core::arch::asm;
+
+#[export_name = "xferv"]
+#[link_section = ".xferv"]
+#[naked]
+unsafe extern "C" fn xferv() {
+    unsafe {
+        asm!(r#"
+            .balign 8; jmp {hi};
+            .balign 8; jmp {bye};
+            "#,
+            hi = sym hi,
+            bye = sym bye,
+            options(att_syntax, noreturn));
+    }
+}
+
+extern "C" fn hi() {
+    uart::panic_println!("Hi!");
+}
+
+extern "C" fn bye() {
+    uart::panic_println!("Bye!");
+}