Remove the addition of USER_ACCESSIBLE flag to every entry created

5 files changed, 26 insertions, 6 deletions

diff --git a/arch/x86_64/include/arch/memory/paging/active_page_table.hpp b/arch/x86_64/include/arch/memory/paging/active_page_table.hpp
index 9e91a8c..a4a5b64 100644
--- a/arch/x86_64/include/arch/memory/paging/active_page_table.hpp
+++ b/arch/x86_64/include/arch/memory/paging/active_page_table.hpp
@@ -89,7 +89,7 @@ namespace teachos::arch::memory::paging
       arch::exception_handling::assert(!level1_entry.contains_flags(entry::HUGE_PAGE),
                                        "[Page Mapper] Unable to map huge pages");
       arch::exception_handling::assert(level1_entry.is_unused(), "[Page Mapper] Page table entry is already used");
-      level1_entry.set_entry(frame, flags.to_ulong() | entry::PRESENT);
+      level1_entry.set_entry(frame, flags.to_ulong() | entry::PRESENT | entry::USER_ACCESSIBLE);
     }
 
     /**
diff --git a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
index 8d36fde..09e9bf4 100644
--- a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
+++ b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
@@ -81,11 +81,12 @@ namespace teachos::arch::memory::paging
           kernel::cpu::read_control_register(kernel::cpu::control_register::CR3));
       auto page_table_level4 = temporary_page.map_table_frame(backup, active_table);
 
-      active_table[511].set_entry(inactive_table.page_table_level_4_frame, entry::PRESENT | entry::WRITABLE);
+      active_table[511].set_entry(inactive_table.page_table_level_4_frame,
+                                  entry::PRESENT | entry::WRITABLE | entry::USER_ACCESSIBLE);
       kernel::cpu::tlb_flush_all();
       map_elf_kernel_sections(active_table);
 
-      page_table_level4[511].set_entry(backup, entry::PRESENT | entry::WRITABLE);
+      page_table_level4[511].set_entry(backup, entry::PRESENT | entry::WRITABLE | entry::USER_ACCESSIBLE);
       kernel::cpu::tlb_flush_all();
       temporary_page.unmap_page(active_table);
     }
@@ -136,7 +137,14 @@ namespace teachos::arch::memory::paging
         allocator::frame_container::iterator const begin{start_frame};
         allocator::frame_container::iterator const end{end_frame};
         allocator::frame_container const frames{begin, end};
-        entry const entry{section.flags};
+        entry entry{section.flags};
+
+        // TODO: Only set this if we are in the .user_text section.
+        // address: 0000000000216000, offset: 013000, size: varies depending on code not a a good idea
+        // Alternatively index Nr. 8 could be used to detect section, can also change if we add more section
+        entry.set_user_accesible();
+
+        // TODO: Entering User Mode still works, but then attempting to execute an instruction immedatiately fails.
 
         for (auto const & frame : frames)
         {
@@ -146,7 +154,7 @@ namespace teachos::arch::memory::paging
 
       auto const vga_buffer_frame =
           allocator::physical_frame::containing_address(video::vga::text::DEFAULT_VGA_TEXT_BUFFER_ADDRESS);
-      active_table.identity_map(allocator, vga_buffer_frame, entry::WRITABLE);
+      active_table.identity_map(allocator, vga_buffer_frame, entry::WRITABLE | entry::USER_ACCESSIBLE);
     }
 
     T & allocator;
diff --git a/arch/x86_64/include/arch/memory/paging/page_entry.hpp b/arch/x86_64/include/arch/memory/paging/page_entry.hpp
index ef4fe61..5cba1bc 100644
--- a/arch/x86_64/include/arch/memory/paging/page_entry.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_entry.hpp
@@ -72,6 +72,12 @@ namespace teachos::arch::memory::paging
     auto set_unused() -> void;
 
     /**
+     * @brief Marks the page as accessible in User mode, meaning the underlying std::bitset has the 2nd bit aditonally
+     * set.
+     */
+    auto set_user_accesible() -> void;
+
+    /**
      * @brief Calculates the physical frame this entry is pointing too, can be null if the page is not present in
      * memory.
      *
diff --git a/arch/x86_64/include/arch/memory/paging/page_table.hpp b/arch/x86_64/include/arch/memory/paging/page_table.hpp
index 60a0a2f..db7ba6c 100644
--- a/arch/x86_64/include/arch/memory/paging/page_table.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_table.hpp
@@ -94,7 +94,8 @@ namespace teachos::arch::memory::paging
       {
         auto const allocated_frame = allocator.allocate_frame();
         exception_handling::assert(allocated_frame.has_value(), "[Page mapper] Unable to allocate frame");
-        this->operator[](table_index).set_entry(allocated_frame.value(), entry::PRESENT | entry::WRITABLE);
+        this->operator[](table_index)
+            .set_entry(allocated_frame.value(), entry::PRESENT | entry::WRITABLE | entry::USER_ACCESSIBLE);
         // There should now be an entry at the previously not existent index, therefore we can simply access it again.
         next_handle = next_table(table_index);
         exception_handling::assert(next_handle.has_value(), "[Page mapper] Unable to create new entry into page table");
diff --git a/arch/x86_64/include/arch/user/main.hpp b/arch/x86_64/include/arch/user/main.hpp
index 4f1d005..ba30864 100644
--- a/arch/x86_64/include/arch/user/main.hpp
+++ b/arch/x86_64/include/arch/user/main.hpp
@@ -3,6 +3,11 @@
 
 namespace teachos::arch::user
 {
+  /**
+   * @brief User Main method. If this method finishes there is no code left to run and the whole OS will shut down.
+   * Additionally this main method is executed at Ring 3 and accessing CPU Registers or Kernel level functionality can
+   * only be done over syscalls and not directly anymore.
+   */
   auto main() -> void;
 
 }  // namespace teachos::arch::user