Add ## Safety headings to doc comments

Author: phil-opp

src/structures/paging/frame_alloc.rs

@@ -25,6 +25,8 @@ pub struct UnusedPhysFrame<S: PageSize = Size4KiB>(PhysFrame<S>);
 impl<S: PageSize> UnusedPhysFrame<S> {
     /// Creates a new UnusedPhysFrame from the given frame.
     ///
+    /// ## Safety
+    ///
     /// This method is unsafe because the caller must guarantee
     /// that the given frame is unused.
     pub unsafe fn new(frame: PhysFrame<S>) -> Self {

src/structures/paging/mapper/mapped_page_table.rs

@@ -23,6 +23,8 @@ impl<'a, P: PhysToVirt> MappedPageTable<'a, P> {
     /// Creates a new `MappedPageTable` that uses the passed closure for converting virtual
     /// to physical addresses.
     ///
+    /// ## Safety
+    ///
     /// This function is unsafe because the caller must guarantee that the passed `phys_to_virt`
     /// closure is correct. Also, the passed `level_4_table` must point to the level 4 page table
     /// of a valid page table hierarchy. Otherwise this function might break memory safety, e.g.

src/structures/paging/mapper/recursive_page_table.rs

@@ -66,6 +66,8 @@ impl<'a> RecursivePageTable<'a> {
 
     /// Creates a new RecursivePageTable without performing any checks.
     ///
+    /// ## Safety
+    ///
     /// The `recursive_index` parameter must be the index of the recursively mapped entry.
     #[inline]
     pub unsafe fn new_unchecked(table: &'a mut PageTable, recursive_index: PageTableIndex) -> Self {

src/structures/port.rs

@@ -7,6 +7,8 @@
 pub trait PortRead {
     /// Reads a `Self` value from the given port.
     ///
+    /// ## Safety
+    ///
     /// This function is unsafe because the I/O port could have side effects that violate memory
     /// safety.
     unsafe fn read_from_port(port: u16) -> Self;
@@ -19,6 +21,8 @@ pub trait PortRead {
 pub trait PortWrite {
     /// Writes a `Self` value to the given port.
     ///
+    /// ## Safety
+    ///
     /// This function is unsafe because the I/O port could have side effects that violate memory
     /// safety.
     unsafe fn write_to_port(port: u16, value: Self);