Convert elf section flags to entry flags

1 files changed, 21 insertions, 1 deletions

diff --git a/arch/x86_64/src/memory/paging/page_entry.cpp b/arch/x86_64/src/memory/paging/page_entry.cpp
index 23c700f..5c4bc67 100644
--- a/arch/x86_64/src/memory/paging/page_entry.cpp
+++ b/arch/x86_64/src/memory/paging/page_entry.cpp
@@ -7,7 +7,8 @@ namespace teachos::arch::memory::paging
   namespace
   {
     std::size_t constexpr PHYSICAL_ADDRESS_MASK = 0x000fffff'fffff000;
-  }
+    std::size_t constexpr ENTRY_FLAGS_MASK = 0xfff00000'00000fff;
+  }  // namespace
 
   entry::entry(uint64_t flags)
       : flags(flags)
@@ -15,6 +16,23 @@ namespace teachos::arch::memory::paging
     // Nothing to do.
   }
 
+  entry::entry(multiboot::elf_section_flags elf_flags)
+  {
+    if (elf_flags.contains_flags(multiboot::elf_section_flags::OCCUPIES_MEMORY))
+    {
+      flags = flags.to_ulong() | entry::PRESENT;
+    }
+    if (elf_flags.contains_flags(multiboot::elf_section_flags::WRITABLE))
+    {
+      flags = flags.to_ulong() | entry::WRITABLE;
+    }
+    if (!elf_flags.contains_flags(multiboot::elf_section_flags::EXECUTABLE_CODE))
+    {
+      // TODO: Ensure to set the NXE bit, if we don't using this entry flag causes crashes
+      // flags = flags.to_ulong() | entry::EXECUTING_CODE_FORBIDDEN;
+    }
+  }
+
   auto entry::is_unused() const -> bool { return flags == 0U; }
 
   auto entry::set_unused() -> void { flags = 0U; }
@@ -37,4 +55,6 @@ namespace teachos::arch::memory::paging
                                "[Paging Entry] Start address is not aligned with page");
     flags = frame.start_address() | additional_flags.to_ulong();
   }
+
+  auto entry::get_flags() -> std::bitset<64U> { return flags.to_ulong() & ENTRY_FLAGS_MASK; }
 }  // namespace teachos::arch::memory::paging