x86_64/memory: fix temporary page unmapping

2 files changed, 35 insertions, 1 deletions

diff --git a/arch/x86_64/src/kapi/memory.cpp b/arch/x86_64/src/kapi/memory.cpp
index 703b3e1..0e4b78e 100644
--- a/arch/x86_64/src/kapi/memory.cpp
+++ b/arch/x86_64/src/kapi/memory.cpp
@@ -8,6 +8,7 @@
 #include "x86_64/memory/buffered_allocator.hpp"
 #include "x86_64/memory/mmu.hpp"
 #include "x86_64/memory/page_table.hpp"
+#include "x86_64/memory/page_utilities.hpp"
 #include "x86_64/memory/paging_root.hpp"
 #include "x86_64/memory/region_allocator.hpp"
 #include "x86_64/memory/scoped_mapping.hpp"
@@ -63,15 +64,46 @@ namespace teachos::memory
       using namespace x86_64;
       using entry_flags = page_table::entry::flags;
 
-      auto temporary_mapper = scoped_mapping{page::containing(unused_page_address), allocator};
+      auto page = page::containing(unused_page_address);
+
+      auto temporary_mapper = scoped_mapping{page, allocator};
       auto new_pml4_frame = allocator.allocate();
 
       auto pml4 = std::construct_at(temporary_mapper.map_as<page_table>(*new_pml4_frame, entry_flags::writable));
       (*pml4)[recursive_page_map_index].frame(new_pml4_frame.value(), entry_flags::present | entry_flags::writable);
+
+      auto pml4_index = pml_index<4>(page);
+      auto & old_pml4 = paging_root::get();
+      auto pml4_entry = old_pml4[pml4_index];
+
+      auto pml3_index = pml_index<3>(page);
+      auto old_pml3 = old_pml4.next(pml4_index);
+      auto pml3_entry = (**old_pml3)[pml3_index];
+
+      auto pml2_index = pml_index<2>(page);
+      auto old_pml2 = (**old_pml3).next(pml3_index);
+      auto pml2_entry = (**old_pml2)[pml2_index];
+
+      auto pml1_index = pml_index<1>(page);
+      auto old_pml1 = (**old_pml2).next(pml2_index);
+      auto pml1_entry = (**old_pml1)[pml1_index];
+
       paging_root::get()[recursive_page_map_index].frame(new_pml4_frame.value(),
                                                          entry_flags::present | entry_flags::writable);
 
       tlb_flush_all();
+
+      auto & new_pml4 = paging_root::get();
+      new_pml4[pml4_index] = pml4_entry;
+
+      auto new_pml3 = new_pml4.next(pml4_index);
+      (**new_pml3)[pml3_index] = pml3_entry;
+
+      auto new_pml2 = (**new_pml3).next(pml3_index);
+      (**new_pml2)[pml2_index] = pml2_entry;
+
+      auto new_pml1 = (**new_pml2).next(pml2_index);
+      (**new_pml1)[pml1_index] = pml1_entry;
     }
 
   }  // namespace
diff --git a/arch/x86_64/src/memory/scoped_mapping.cpp b/arch/x86_64/src/memory/scoped_mapping.cpp
index 602198e..191a7ad 100644
--- a/arch/x86_64/src/memory/scoped_mapping.cpp
+++ b/arch/x86_64/src/memory/scoped_mapping.cpp
@@ -89,6 +89,8 @@ namespace teachos::memory::x86_64
     auto pml1_index = pml_index<1>(m_page);
     (*pml1)[pml1_index].frame(frame, page_table::entry::flags::present | flags);
 
+    m_mapped = true;
+
     return static_cast<std::byte *>(frame.start_address());
   }