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 = "2024"
 [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

@@ -1,4 +1,4 @@
-// Copyright 2021  The Hypatia Authors
+// Copyright 2023  The Hypatia Authors
 // All rights reserved
 //
 // Use of this source code is governed by an MIT-style
@@ -11,6 +11,8 @@
 #![forbid(elided_lifetimes_in_paths)]
 #![forbid(unsafe_op_in_unsafe_fn)]
 
+mod x86_64;
+
 use arch::Page4K;
 
 /// Returns a static reference to the global zero page.
@@ -23,6 +25,7 @@ pub fn zero_page() -> &'static Page4K {
 #[unsafe(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 +1,29 @@
+// 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::naked_asm;
+
+#[unsafe(export_name = "xferv")]
+#[unsafe(link_section = ".xferv")]
+#[unsafe(naked)]
+unsafe extern "C" fn xferv() {
+    naked_asm!(r#"
+        .balign 8; jmp {hi};
+        .balign 8; jmp {bye};
+        "#,
+        hi = sym hi,
+        bye = sym bye,
+        options(att_syntax));
+}
+
+extern "C" fn hi() {
+    uart::panic_println!("Hi!");
+}
+
+extern "C" fn bye() {
+    uart::panic_println!("Bye!");
+}