check if entry contains a frame

Author: Freax13

src/structures/paging/mapper/mod.rs

@@ -18,6 +18,8 @@ use crate::structures::paging::{
 };
 use crate::{PhysAddr, VirtAddr};
 
+use super::page_table::FrameError;
+
 mod mapped_page_table;
 mod offset_page_table;
 #[cfg(feature = "instructions")]
@@ -793,6 +795,15 @@ pub enum UnmapError {
     InvalidFrameAddress(PhysAddr),
 }
 
+impl From<FrameError> for UnmapError {
+    fn from(e: FrameError) -> Self {
+        match e {
+            FrameError::FrameNotPresent => Self::PageNotMapped,
+            FrameError::HugeFrame => Self::ParentEntryHugePage,
+        }
+    }
+}
+
 impl From<Infallible> for UnmapError {
     fn from(i: Infallible) -> Self {
         match i {}
@@ -809,6 +820,15 @@ pub enum FlagUpdateError {
     ParentEntryHugePage,
 }
 
+impl From<FrameError> for FlagUpdateError {
+    fn from(e: FrameError) -> Self {
+        match e {
+            FrameError::FrameNotPresent => Self::PageNotMapped,
+            FrameError::HugeFrame => Self::ParentEntryHugePage,
+        }
+    }
+}
+
 impl From<Infallible> for FlagUpdateError {
     fn from(i: Infallible) -> Self {
         match i {}

src/structures/paging/mapper/recursive_page_table.rs

@@ -305,9 +305,10 @@ impl<'a> RecursivePageTable<'a> {
     #[cfg(feature = "experimental")]
     unsafe fn next_table_fn_next_table_mut<'b, I>(
         _: &mut I,
-        _: &'b mut PageTableEntry,
+        e: &'b mut PageTableEntry,
         page: Page,
-    ) -> Result<&'b mut PageTable, Infallible> {
+    ) -> Result<&'b mut PageTable, FrameError> {
+        e.frame()?;
         Ok(&mut *page.start_address().as_mut_ptr())
     }