From d1d310f1d1127dac75f25aa27ae1c88489ade775 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Wed, 1 May 2024 20:24:59 +0200
Subject: [PATCH] remove assembly code and replace it by helper crates

---
 Cargo.lock                    | 32 ++++++++++++++++++++++++++++++++
 Cargo.toml                    | 13 +++++++------
 src/arch/aarch64/processor.rs | 15 ++-------------
 src/arch/x86_64/processor.rs  | 23 ++++++++++++++---------
 src/main.rs                   |  4 ++--
 5 files changed, 57 insertions(+), 30 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index fa54d8e4..87b40813 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -51,7 +51,9 @@ dependencies = [
  "bootloader",
  "hermit-sync",
  "qemu-exit",
+ "semihosting",
  "x86",
+ "x86_64",
 ]
 
 [[package]]
@@ -156,12 +158,24 @@ dependencies = [
  "bitflags 1.3.2",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "80af6f9131f277a45a3fba6ce8e2258037bb0477a67e610d3c1fe046ab31de47"
+
 [[package]]
 name = "scopeguard"
 version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "semihosting"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a5260e8474680a4617e36cee7f4602655c89146bde012a5b6ba7cc080ec49dcd"
+
 [[package]]
 name = "spinning_top"
 version = "0.3.0"
@@ -171,6 +185,12 @@ dependencies = [
  "lock_api",
 ]
 
+[[package]]
+name = "volatile"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "442887c63f2c839b346c192d047a7c87e73d0689c9157b00b53dcc27dd5ea793"
+
 [[package]]
 name = "x86"
 version = "0.52.0"
@@ -181,3 +201,15 @@ dependencies = [
  "bitflags 1.3.2",
  "raw-cpuid",
 ]
+
+[[package]]
+name = "x86_64"
+version = "0.15.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bc79523af8abf92fb1a970c3e086c5a343f6bcc1a0eb890f575cbb3b45743df"
+dependencies = [
+ "bit_field",
+ "bitflags 2.5.0",
+ "rustversion",
+ "volatile",
+]
diff --git a/Cargo.toml b/Cargo.toml
index a802f1b9..f9e6d29e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,7 @@ build-command = ["build"]
 # The command invoked with the created bootimage (the "{}" will be replaced
 # with the path to the bootable disk image)
 # Applies to `bootimage run` and `bootimage runner`
-run-command = ["qemu-system-x86_64", "-display", "none", "-smp", "1", "-m", "128M", "-serial", "stdio", "-cpu", "qemu64,apic,fsgsbase,rdtscp,xsave,xsaveopt,fxsr", "-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-drive", "format=raw,file={}"]
+run-command = ["qemu-system-x86_64", "-display", "none", "-smp", "1", "-m", "256M", "-serial", "stdio", "-cpu", "qemu64,apic,fsgsbase,rdtscp,xsave,xsaveopt,fxsr", "-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-drive", "format=raw,file={}"]
 # Additional arguments passed to the run command for non-test executables
 # Applies to `bootimage run` and `bootimage runner`
 run-args = []
@@ -19,10 +19,11 @@ run-args = []
 hermit-sync = "0.1.6"
 qemu-exit = "3.0"	# Spinlocks.
 
-[target.'cfg(target_arch = "x86_64")'.dependencies.bootloader]
-version = "0.9.29"
+[target.'cfg(target_arch = "aarch64")'.dependencies]
+semihosting = "0.1.9"
 
-[target.'cfg(target_arch = "x86_64")'.dependencies.x86]
-version = "0.52"
-default-features = false
+[target.'cfg(target_arch = "x86_64")'.dependencies]
+bootloader = "0.9.29"
+x86 = { version = "0.52", default-features = false }
+x86_64 = "0.15"
 
diff --git a/src/arch/aarch64/processor.rs b/src/arch/aarch64/processor.rs
index 503b0abb..98f50379 100644
--- a/src/arch/aarch64/processor.rs
+++ b/src/arch/aarch64/processor.rs
@@ -1,15 +1,4 @@
-#![allow(dead_code)]
-use core::arch::asm;
-
 #[no_mangle]
-pub extern "C" fn shutdown() -> ! {
-	unsafe {
-		asm!(
-			"mov w0, 0x18",
-			"mov x1, #0x20000",
-			"add x1, x1, #0x26",
-			"hlt #0xF000",
-			options(nostack, nomem, noreturn),
-		);
-	}
+pub extern "C" fn shutdown(error_code: i32) -> ! {
+	semihosting::process::exit(error_code)
 }
diff --git a/src/arch/x86_64/processor.rs b/src/arch/x86_64/processor.rs
index 08b01f85..5223f7c7 100644
--- a/src/arch/x86_64/processor.rs
+++ b/src/arch/x86_64/processor.rs
@@ -1,20 +1,25 @@
-#![allow(dead_code)]
-
-use core::arch::asm;
-use qemu_exit::QEMUExit;
 use x86::controlregs::*;
+use x86_64::instructions::port::Port;
 
 pub fn halt() {
 	unsafe {
-		asm!("hlt", options(nomem, nostack));
+		x86::halt();
+	}
+}
+
+fn qemu_exit(success: bool) {
+	let code = if success { 3 >> 1 } else { 0 };
+	unsafe {
+		Port::<u32>::new(0xf4).write(code);
 	}
 }
 
 #[no_mangle]
-pub extern "C" fn shutdown() -> ! {
-	// shutdown, works like Qemu's shutdown command
-	let qemu_exit_handle = qemu_exit::X86::new(0xf4, 5);
-	qemu_exit_handle.exit_success();
+pub extern "C" fn shutdown(error_code: i32) -> ! {
+	qemu_exit(error_code == 0);
+	loop {
+		halt();
+	}
 }
 
 pub fn cpu_init() {
diff --git a/src/main.rs b/src/main.rs
index 49fc0170..badf975f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -17,7 +17,7 @@ pub extern "C" fn main() -> ! {
 	println!("Hello world!");
 
 	// shutdown system
-	shutdown();
+	shutdown(0);
 }
 
 /// This function is called on panic.
@@ -36,5 +36,5 @@ pub fn panic(info: &PanicInfo) -> ! {
 
 	print!("\n");
 
-	loop {}
+	shutdown(1);
 }