paging: Allow passing EntryFlags not marked 'valid' to map()

This allows mappings to be invalidated.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/paging.zig b/src/paging.zig
index 1a174aa..d1d309c 100644
--- a/src/paging.zig
+++ b/src/paging.zig
@@ -292,13 +292,13 @@ pub const Table = struct {
     // discarding offsets. The mapping is written to the specified level,
     // creating page tables as needed.
     //
-    // The mapping must be a leaf, meaning that passing flags
+    // The mapping must be invalid or a leaf, meaning that passing flags
     // that indicate no access permissions at all will return an error.
     //
     // This function internally uses zeroedAlloc to allocate memory for the required page tables,
     // but assumes that the physical address to map to has already been allocated by the caller.
     pub fn map(root: *Table, vaddr: usize, paddr: usize, flags: EntryFlags, level: usize) !void {
-        if (!flags.isLeaf()) return Error.NotALeaf;
+        if (@bitCast(flags.valid) and !flags.isLeaf()) return Error.NotALeaf;
 
         const vpn = virtualPageNumbers(vaddr);