Physical Memory Management Improvements.

rust/lib/mammoth/src/physical_box.rs

@@ -0,0 +1,131 @@
+use core::{
+    marker::PhantomData,
+    ops::{Deref, DerefMut, Index, IndexMut},
+    ptr::NonNull,
+};
+
+use alloc::{slice, vec::Vec};
+
+use crate::mem::MemoryRegion;
+
+pub struct PhysicalBox<T: ?Sized> {
+    data: NonNull<T>,
+    region: MemoryRegion,
+    physical_address: usize,
+    _marker: PhantomData<T>,
+}
+
+impl<T: ?Sized> PhysicalBox<T> {
+    pub fn physical_address(&self) -> usize {
+        self.physical_address
+    }
+}
+
+impl<T: ?Sized> Deref for PhysicalBox<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY:
+        //   - Alignment: This is page aligned.
+        //   - Dereferenceable: Guaranteed in same allocation.
+        //   - Aliasing: The borrow rules ensure this
+        unsafe { self.data.as_ref() }
+    }
+}
+
+impl<T: ?Sized> DerefMut for PhysicalBox<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        // SAFETY:
+        //   - Alignment: This is page aligned.
+        //   - Dereferenceable: Guaranteed in same allocation.
+        //   - Aliasing: The borrow rules ensure this
+        unsafe { self.data.as_mut() }
+    }
+}
+
+impl<T> PhysicalBox<[T]> {
+    pub fn default_with_count(default: T, len: usize) -> Self
+    where
+        T: Clone,
+    {
+        let layout = core::alloc::Layout::array::<T>(len).expect("Layout overflow");
+
+        // TODO: Implement a function like alloc that takes a layout. let (memory_region, paddr) =
+        let (memory_region, paddr) =
+            MemoryRegion::contiguous_physical(layout.size() as u64).expect("Failed to allocate");
+
+        let ptr: *mut T = memory_region.mut_ptr_at_offset(0);
+        for i in 0..len {
+            unsafe {
+                ptr.add(i).write(default.clone());
+            }
+        }
+
+        let slice_ptr = core::ptr::slice_from_raw_parts_mut(ptr, len);
+
+        Self {
+            // UNWRAP: We know this isn't null.
+            data: NonNull::new(slice_ptr).unwrap(),
+            region: memory_region,
+            physical_address: paddr as usize,
+            _marker: PhantomData,
+        }
+    }
+
+    pub fn from_vec(mut vec: Vec<T>) -> Self {
+        let len = vec.len();
+        let layout = core::alloc::Layout::array::<T>(len).expect("Layout overflow");
+
+        // TODO: Implement a function like alloc that takes a layout.
+        let (memory_region, paddr) =
+            MemoryRegion::contiguous_physical(layout.size() as u64).expect("Failed to allocate");
+
+        let ptr: *mut T = memory_region.mut_ptr_at_offset(0);
+        for (i, item) in vec.into_iter().enumerate() {
+            unsafe {
+                ptr.add(i).write(item);
+            }
+        }
+
+        let slice_ptr = core::ptr::slice_from_raw_parts_mut(ptr, len);
+
+        Self {
+            // UNWRAP: We know this isn't null.
+            data: NonNull::new(slice_ptr).unwrap(),
+            region: memory_region,
+            physical_address: paddr as usize,
+            _marker: PhantomData,
+        }
+    }
+    pub fn len(&self) -> usize {
+        (**self).len()
+    }
+}
+
+impl<I, T> Index<I> for PhysicalBox<[T]>
+where
+    I: slice::SliceIndex<[T]>,
+{
+    type Output = I::Output;
+
+    fn index(&self, index: I) -> &Self::Output {
+        &(**self)[index]
+    }
+}
+
+impl<I, T> IndexMut<I> for PhysicalBox<[T]>
+where
+    I: slice::SliceIndex<[T]>,
+{
+    fn index_mut(&mut self, index: I) -> &mut Self::Output {
+        &mut (**self)[index]
+    }
+}
+
+impl<T: ?Sized> Drop for PhysicalBox<T> {
+    fn drop(&mut self) {
+        // SAFETY:
+        //   - We own this data.
+        unsafe { core::ptr::drop_in_place(self.data.as_ptr()) }
+    }
+}