Start of a platform-independent paging interface.

1 files changed, 16 insertions, 7 deletions

diff --git a/crates/device_tree/src/lib.rs b/crates/device_tree/src/lib.rs
index fe6108f..ce29546 100644
--- a/crates/device_tree/src/lib.rs
+++ b/crates/device_tree/src/lib.rs
@@ -23,10 +23,12 @@ pub struct FlattenedDeviceTree<'dt> {
     struct_block: &'dt [u32],
     strings_block: &'dt BStr,
     memrsv_block: &'dt [FdtMemRsv],
+    kernel_addrs: Range<usize>,
 }
 
 impl<'dt> FlattenedDeviceTree<'dt> {
-    /// Looks for a DeviceTree at the given address, and returns it if it looks valid.
+    /// Looks for a DeviceTree at the given address, and returns it if it looks valid. Also accepts
+    /// the bounds of the kernel, so that `iter_reserved` can reserve them.
     ///
     /// # Safety
     ///
@@ -36,7 +38,10 @@ impl<'dt> FlattenedDeviceTree<'dt> {
     /// - The memory contained by the flattened DeviceTree must not be mutated for the duration of
     ///   lifetime `'dt`.
     #[requires((ptr as *const FdtHeader).is_aligned())]
-    pub unsafe fn from_ptr(ptr: *const u8) -> Result<FlattenedDeviceTree<'dt>, DeviceTreeError> {
+    pub unsafe fn from_ptr(
+        ptr: *const u8,
+        kernel_addrs: Range<usize>,
+    ) -> Result<FlattenedDeviceTree<'dt>, DeviceTreeError> {
         // Check that the header appears to point to a valid flattened DeviceTree.
         let header: &'dt FdtHeader = &*(ptr as *const FdtHeader);
         let magic = u32::from_be(header.magic);
@@ -94,6 +99,7 @@ impl<'dt> FlattenedDeviceTree<'dt> {
             struct_block,
             strings_block,
             memrsv_block,
+            kernel_addrs,
         };
         fdt.iter_struct_events_from(0)
             .try_for_each(|r| r.map(|_| ()))?;
@@ -222,6 +228,7 @@ impl<'dt> FlattenedDeviceTree<'dt> {
     ///
     /// Addresses may be reserved by:
     ///
+    /// - Overlapping with the kernel.
     /// - Overlapping with the DeviceTree itself.
     /// - Overlapping with any memory reservations in the DeviceTree.
     pub fn iter_reserved(&self) -> impl '_ + Iterator<Item = Range<usize>> {
@@ -229,11 +236,13 @@ impl<'dt> FlattenedDeviceTree<'dt> {
         let dt_start = self.header as *const FdtHeader as usize;
         let dt_end = dt_start + u32::from_be(self.header.totalsize) as usize;
 
-        iter::once(dt_start..dt_end).chain(self.memrsv_block.iter().map(|memrsv| {
-            let addr = u64::from_be(memrsv.addr) as usize;
-            let size = u64::from_be(memrsv.size) as usize;
-            addr..addr + size
-        }))
+        iter::once(self.kernel_addrs.clone())
+            .chain(iter::once(dt_start..dt_end))
+            .chain(self.memrsv_block.iter().map(|memrsv| {
+                let addr = u64::from_be(memrsv.addr) as usize;
+                let size = u64::from_be(memrsv.size) as usize;
+                addr..addr + size
+            }))
     }
 
     /// Returns an iterator over the events in the structure block of the DeviceTree, starting at