Merge branch 'fmorgner/develop-SA-FS26/kernel-bht' into 'develop-BA-FS26'

Add experimental support for kernel tests

See merge request teachos/kernel!20

1 files changed, 71 insertions, 0 deletions

diff --git a/kernel/src/test_support/kapi/memory.cpp b/kernel/src/test_support/kapi/memory.cpp
new file mode 100644
index 0000000..f244b7f
--- /dev/null
+++ b/kernel/src/test_support/kapi/memory.cpp
@@ -0,0 +1,71 @@
+#include "kapi/memory.hpp"
+
+#include <kapi/memory.hpp>
+
+#include "kernel/test_support/bump_frame_allocator.hpp"
+#include "kernel/test_support/page_mapper.hpp"
+
+#include <kstd/units>
+
+#include <optional>
+
+namespace
+{
+  //! The size of the simulated RAM.
+  constexpr auto memory_size = kstd::units::MiB(32);
+  constexpr auto number_of_frames = memory_size / kapi::memory::frame::size;
+
+  auto constinit bump_allocator = std::optional<kernel::tests::bump_frame_allocator>{};
+  auto constinit test_mapper = std::optional<kernel::tests::page_mapper>{};
+
+  auto constinit old_allocator = std::optional<kapi::memory::frame_allocator *>{};
+  auto constinit old_mapper = std::optional<kapi::memory::page_mapper *>{};
+
+  auto handoff_to_kernel_pmm(kapi::memory::frame_allocator & new_allocator) -> void
+  {
+    auto first_free_frame = bump_allocator->next_free_frame;
+    auto number_of_free_frames = number_of_frames - first_free_frame;
+    new_allocator.release_many({kapi::memory::frame{first_free_frame}, number_of_free_frames});
+  }
+
+}  // namespace
+
+namespace kapi::memory
+{
+
+  auto init() -> void
+  {
+    bump_allocator.emplace();
+    test_mapper.emplace(memory_size);
+
+    old_allocator = set_frame_allocator(*bump_allocator);
+    old_mapper = set_page_mapper(*test_mapper);
+
+    init_pmm(memory_size / frame::size, handoff_to_kernel_pmm);
+  }
+
+  auto reset() -> void
+  {
+    if (old_allocator && *old_allocator)
+    {
+      set_frame_allocator(**old_allocator);
+    }
+
+    if (old_mapper && *old_mapper)
+    {
+      set_page_mapper(**old_mapper);
+    }
+
+    bump_allocator.reset();
+    test_mapper.reset();
+  }
+
+}  // namespace kapi::memory
+
+namespace kernel::tests::memory
+{
+  auto heap_base() -> kapi::memory::linear_address
+  {
+    return test_mapper->memory.heap_base();
+  }
+}  // namespace kernel::tests::memory
\ No newline at end of file