From d3834ed2ff046751686031b351d9ccf50feab33c Mon Sep 17 00:00:00 2001
From: Corwin <corwin@kuiper.dev>
Date: Thu, 6 Apr 2023 20:48:04 +0100
Subject: [PATCH] allocator unsound to use in interrupt

---
 agb/src/agb_alloc/block_allocator.rs | 41 ++++++++++++++--------------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/agb/src/agb_alloc/block_allocator.rs b/agb/src/agb_alloc/block_allocator.rs
index 14eb4638..921a4308 100644
--- a/agb/src/agb_alloc/block_allocator.rs
+++ b/agb/src/agb_alloc/block_allocator.rs
@@ -5,13 +5,10 @@
 
 use core::alloc::{Allocator, GlobalAlloc, Layout};
 
-use core::cell::RefCell;
+use core::cell::UnsafeCell;
 use core::convert::TryInto;
 use core::ptr::NonNull;
 
-use crate::interrupt::free;
-use bare_metal::Mutex;
-
 use super::bump_allocator::{BumpAllocatorInner, StartEnd};
 use super::SendNonNull;
 
@@ -53,36 +50,45 @@ struct BlockAllocatorInner {
 }
 
 pub struct BlockAllocator {
-    inner: Mutex<RefCell<BlockAllocatorInner>>,
+    inner: UnsafeCell<BlockAllocatorInner>,
 }
 
+unsafe impl Sync for BlockAllocator {}
+
 impl BlockAllocator {
     pub(crate) const unsafe fn new(start: StartEnd) -> Self {
         Self {
-            inner: Mutex::new(RefCell::new(BlockAllocatorInner::new(start))),
+            inner: UnsafeCell::new(BlockAllocatorInner::new(start)),
         }
     }
 
+    #[inline(always)]
+    unsafe fn with_inner<F, T>(&self, f: F) -> T
+    where
+        F: Fn(&mut BlockAllocatorInner) -> T,
+    {
+        let inner = &mut *self.inner.get();
+
+        f(inner)
+    }
+
     #[doc(hidden)]
     #[cfg(any(test, feature = "testing"))]
     pub unsafe fn number_of_blocks(&self) -> u32 {
-        free(|key| self.inner.borrow(key).borrow_mut().number_of_blocks())
+        self.with_inner(|inner| inner.number_of_blocks())
     }
 
     pub unsafe fn alloc(&self, layout: Layout) -> Option<NonNull<u8>> {
-        free(|key| self.inner.borrow(key).borrow_mut().alloc(layout))
+        self.with_inner(|inner| inner.alloc(layout))
     }
 
     pub unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
-        free(|key| self.inner.borrow(key).borrow_mut().dealloc(ptr, layout));
+        self.with_inner(|inner| inner.dealloc(ptr, layout));
     }
 
     pub unsafe fn dealloc_no_normalise(&self, ptr: *mut u8, layout: Layout) {
-        free(|key| {
-            self.inner
-                .borrow(key)
-                .borrow_mut()
-                .dealloc_no_normalise(ptr, layout);
+        self.with_inner(|inner| {
+            inner.dealloc_no_normalise(ptr, layout);
         });
     }
 
@@ -92,12 +98,7 @@ impl BlockAllocator {
         layout: Layout,
         new_layout: Layout,
     ) -> Option<NonNull<u8>> {
-        free(|key| {
-            self.inner
-                .borrow(key)
-                .borrow_mut()
-                .grow(ptr, layout, new_layout)
-        })
+        self.with_inner(|inner| inner.grow(ptr, layout, new_layout))
     }
 }