os: rework kernel architecture

Rework the code structure and architecture of the kernel by separating
platform-dependent and platform-independent code more cleanly. As of
this patchset, full feature parity has not been achieved. Nonetheless, a
sufficient subset of functionality has been ported to the new
architecture to demonstrate the feasibility of the new structure.

1 files changed, 69 insertions, 0 deletions

diff --git a/arch/x86_64/src/memory/scoped_mapping.cpp b/arch/x86_64/src/memory/scoped_mapping.cpp
new file mode 100644
index 0000000..a86aaed
--- /dev/null
+++ b/arch/x86_64/src/memory/scoped_mapping.cpp
@@ -0,0 +1,69 @@
+#include "x86_64/memory/scoped_mapping.hpp"
+
+#include "kapi/memory.hpp"
+#include "kapi/system.hpp"
+
+#include "x86_64/memory/mmu.hpp"
+#include "x86_64/memory/page_table.hpp"
+#include "x86_64/memory/paging_root.hpp"
+
+#include <cstddef>
+#include <utility>
+
+namespace teachos::memory::x86_64
+{
+
+  scoped_mapping::scoped_mapping(scoped_mapping && other) noexcept
+      : m_page{std::exchange(other.m_page, page{})}
+      , m_mapper{std::exchange(other.m_mapper, nullptr)}
+      , m_mapped{std::exchange(other.m_mapped, false)}
+  {}
+
+  scoped_mapping::scoped_mapping(page page, page_mapper & mapper)
+      : m_page{page}
+      , m_mapper{&mapper}
+      , m_mapped{false}
+  {
+    if (paging_root::get()->translate(page))
+    {
+      system::panic("[MEM] Tried to map a page that is already mapped!");
+    }
+  }
+
+  scoped_mapping::~scoped_mapping()
+  {
+    if (m_mapped)
+    {
+      unmap();
+      x86_64::tlb_flush(m_page.start_address());
+    }
+  }
+
+  auto scoped_mapping::operator=(scoped_mapping && other) noexcept -> scoped_mapping &
+  {
+    swap(*this, other);
+    return *this;
+  }
+
+  auto scoped_mapping::map(frame frame, page_table::entry::flags flags) -> std::byte *
+  {
+    auto result = m_mapper->map(m_page, frame, to_mapper_flags(flags));
+    m_mapped = true;
+    return result;
+  }
+
+  auto scoped_mapping::unmap() -> void
+  {
+    m_mapper->unmap(m_page);
+    m_mapped = false;
+  }
+
+  auto swap(scoped_mapping & lhs, scoped_mapping & rhs) -> void
+  {
+    using std::swap;
+    swap(lhs.m_page, rhs.m_page);
+    swap(lhs.m_mapper, rhs.m_mapper);
+    swap(lhs.m_mapped, rhs.m_mapped);
+  }
+
+}  // namespace teachos::memory::x86_64
\ No newline at end of file