Support mmap in initfs

initfs/src/lib.rs

@@ -182,7 +182,7 @@ impl<'initfs> InodeStruct<'initfs> {
 }
 
 impl<'initfs> InitFs<'initfs> {
-    pub fn new(base: &'initfs [u8]) -> Result<Self> {
+    pub fn new(base: &'initfs [u8], required_page_size: Option<u16>) -> Result<Self> {
         let this = Self { base };
 
         if base.len() < core::mem::size_of::<Header>() {
@@ -214,6 +214,12 @@ impl<'initfs> InitFs<'initfs> {
             return Err(Error);
         }
 
+        if let Some(required_page_size) = required_page_size
+            && header.page_size.get() != required_page_size
+        {
+            return Err(Error);
+        }
+
         // From now on, we can be completely sure that the header and inode tables offsets are
         // valid, and thus continue based on that assumption.
 

initfs/src/types.rs

@@ -73,6 +73,7 @@ pub struct Header {
     pub inode_count: U16,
     pub bootstrap_entry: U64,
     pub initfs_size: U64,
+    pub page_size: U16,
 }
 
 const _: () = {