garbage self made raw spin lock 😎

kernel/Cargo.lock

@@ -86,7 +86,6 @@ dependencies = [
  "linked_list_allocator",
  "pc-keyboard",
  "pic8259",
- "spin 0.9.8",
  "uart_16550",
  "x86_64",
 ]
@@ -97,7 +96,7 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 dependencies = [
- "spin 0.5.2",
+ "spin",
 ]
 
 [[package]]
@@ -176,15 +175,6 @@ version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
 
-[[package]]
-name = "spin"
-version = "0.9.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
-dependencies = [
- "lock_api",
-]
-
 [[package]]
 name = "spinning_top"
 version = "0.2.5"

kernel/Cargo.toml

@@ -10,7 +10,6 @@ bench = false
 
 [dependencies]
 embedded-graphics = "0.8.1"
-spin = "0.9.8"
 pc-keyboard = "0.5.0"
 linked_list_allocator = "0.10.5"
 

kernel/src/arch/riscv64/init.rs

@@ -13,6 +13,8 @@ static mut DT_ADDR: *mut FDT = null_mut();
 #[naked]
 unsafe extern "C" fn _start() -> ! {
     core::arch::asm!(
+        // disable interrupts
+        "csrw mie, zero",
         // set up gp & sp
         ".option push",
         ".option norelax",

kernel/src/arch/riscv64/qemu.rs

@@ -1,6 +1,6 @@
 use core::fmt::{self, Write};
 
-use spin::Mutex;
+use crate::util::mutex::Mutex;
 
 // --machine sifive_u
 // const UART_BASE: u32 = 0x10010000;

kernel/src/arch/x86_64/interrupts.rs

@@ -104,5 +104,5 @@ extern "x86-interrupt" fn keyboard(_stack_frame: InterruptStackFrame) {
 pub const PIC_1_OFFSET: u8 = 32;
 pub const PIC_2_OFFSET: u8 = PIC_1_OFFSET + 8;
 
-pub static PICS: spin::Mutex<ChainedPics> =
+pub static PICS: Mutex<ChainedPics> =
-    spin::Mutex::new(unsafe { ChainedPics::new(PIC_1_OFFSET, PIC_2_OFFSET) });
+    Mutex::new(unsafe { ChainedPics::new(PIC_1_OFFSET, PIC_2_OFFSET) });

kernel/src/arch/x86_64/qemu.rs

@@ -1,6 +1,5 @@
 use core::fmt::Arguments;
 
-use spin::Mutex;
 use uart_16550::SerialPort;
 use x86_64::instructions::{interrupts, port::Port};
 

kernel/src/main.rs

@@ -21,6 +21,10 @@ pub fn main(dt_addr: *mut FDT) -> ! {
     let mut test = alloc::vec![1, 2, 3];
     test.push(3);
     println!("{:?}", test);
+    unsafe {
+        let x = *(0x3000 as *const u8);
+        println!("{}", x);
+    }
     // for _ in 0..40000000 {}
     // let x = unsafe { *(0x10000000000 as *mut u8) };
     // println!("we got {x}");

kernel/src/util/mutex.rs

@@ -1,25 +1,27 @@
+use core::ops::{Deref, DerefMut};
+
 use super::spin::SpinLock;
 
-struct Mutex<T> {
+pub struct Mutex<T> {
     lock: SpinLock,
     val: T,
 }
 
 impl<T> Mutex<T> {
-    pub fn new(val: T) -> Self {
+    pub const fn new(val: T) -> Self {
         Self {
             lock: SpinLock::new(),
             val,
         }
     }
-    pub fn lock(&mut self) -> MutexGuard<T> {
+    pub fn lock(&self) -> MutexGuard<T> {
         self.lock.lock();
         MutexGuard { mutex: self }
     }
 }
 
-struct MutexGuard<'a, T> {
+pub struct MutexGuard<'a, T> {
-    mutex: &'a mut Mutex<T>,
+    mutex: &'a Mutex<T>,
 }
 
 impl<'a, T> Drop for MutexGuard<'a, T> {
@@ -27,3 +29,16 @@ impl <'a, T> Drop for MutexGuard<'a, T> {
         self.mutex.lock.unlock();
     }
 }
+
+impl<'a, T> Deref for MutexGuard<'a, T> {
+    type Target = T;
+    fn deref(&self) -> &Self::Target {
+        &self.mutex.val
+    }
+}
+
+impl<'a, T> DerefMut for MutexGuard<'a, T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        unsafe {&mut (*(self.mutex as *const Mutex<T> as *mut Mutex<T>)).val}
+    }
+}

kernel/src/util/spin.rs

@@ -5,15 +5,15 @@ pub struct SpinLock {
 }
 
 impl SpinLock {
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         Self {
             locked: AtomicBool::new(false),
         }
     }
-    pub fn lock(&mut self) {
+    pub fn lock(&self) {
         while self.locked.swap(true, Ordering::Acquire) {}
     }
-    pub fn unlock(&mut self) {
+    pub fn unlock(&self) {
         self.locked.store(false, Ordering::Release)
     }
 }