memory::paging::entry::Entry: implement flag loading from ELF section

src/arch/x86_64/memory/paging/entry.rs

@@ -1,5 +1,6 @@
 //! Page table entry (meta)data
 
+use multiboot2::ElfSection;
 use arch::x86_64::memory::Frame;
 
 pub struct Entry(u64);
@@ -50,3 +51,24 @@ bitflags! {
         const NO_EXECUTE =      1 << 63;
     }
 }
+
+impl EntryFlags {
+    pub fn from_elf_section_flags(section: &ElfSection) -> EntryFlags {
+        use multiboot2::{ELF_SECTION_ALLOCATED, ELF_SECTION_WRITABLE,
+            ELF_SECTION_EXECUTABLE};
+
+        let mut flags = EntryFlags::empty();
+
+        if section.flags().contains(ELF_SECTION_ALLOCATED) {
+            flags = flags | PRESENT;
+        }
+        if section.flags().contains(ELF_SECTION_WRITABLE) {
+            flags = flags | WRITABLE;
+        }
+        if !section.flags().contains(ELF_SECTION_EXECUTABLE) {
+            flags = flags | NO_EXECUTE;
+        }
+
+        flags
+    }
+}