implement basic heap and remap it

9 files changed, 149 insertions, 62 deletions

diff --git a/arch/x86_64/CMakeLists.txt b/arch/x86_64/CMakeLists.txt
index 1444054..5b0e3a9 100644
--- a/arch/x86_64/CMakeLists.txt
+++ b/arch/x86_64/CMakeLists.txt
@@ -41,6 +41,7 @@ target_sources("_video" PRIVATE
 #]============================================================================]
 
 target_sources("_memory" PRIVATE
+  "src/memory/main.cpp"
   "src/memory/multiboot/elf_symbols_section.cpp"
   "src/memory/multiboot/reader.cpp"
   "src/memory/allocator/area_frame_allocator.cpp"
@@ -55,6 +56,7 @@ target_sources("_memory" PRIVATE
   "src/memory/cpu/tlb.cpp"
   "src/memory/cpu/control_register.cpp"
   "src/memory/cpu/msr.cpp"
+  "src/memory/heap/allocator.cpp"
 )
 
 #[============================================================================[
diff --git a/arch/x86_64/include/arch/memory/heap/allocator.hpp b/arch/x86_64/include/arch/memory/heap/allocator.hpp
new file mode 100644
index 0000000..c486a4c
--- /dev/null
+++ b/arch/x86_64/include/arch/memory/heap/allocator.hpp
@@ -0,0 +1,32 @@
+#ifndef TEACHOS_ARCH_X86_64_MEMORY_HEAP_ALLOCATOR_HPP
+#define TEACHOS_ARCH_X86_64_MEMORY_HEAP_ALLOCATOR_HPP
+
+#include <cstdint>
+
+namespace teachos::arch::memory::heap
+{
+  std::size_t constexpr HEAP_START = 0x4000'0000;
+  std::size_t constexpr HEAP_SIZE = 100 * 1024;
+
+  struct bump_allocator
+  {
+    bump_allocator(std::size_t heap_start, std::size_t heap_end)
+        : heap_start{heap_start}
+        , heap_end{heap_end}
+        , next{heap_start}
+    {
+    }
+
+    auto allocate(std::size_t size) -> void *;
+
+    auto deallocate(uint8_t * pointer, std::size_t size) -> void;
+
+  private:
+    std::size_t heap_start;
+    std::size_t heap_end;
+    std::size_t next;
+  };
+
+}  // namespace teachos::arch::memory::heap
+
+#endif
\ No newline at end of file
diff --git a/arch/x86_64/include/arch/memory/heap/concept.hpp b/arch/x86_64/include/arch/memory/heap/concept.hpp
new file mode 100644
index 0000000..a525b0b
--- /dev/null
+++ b/arch/x86_64/include/arch/memory/heap/concept.hpp
@@ -0,0 +1,15 @@
+#ifndef TEACHOS_ARCH_X86_64_MEMORY_HEAP_CONCEPT_HPP
+#define TEACHOS_ARCH_X86_64_MEMORY_HEAP_CONCEPT_HPP
+
+#include <cstdint>
+
+namespace teachos::arch::memory::heap
+{
+  template<typename T>
+  concept HeapAllocator = requires(T t, uint8_t * pointer, std::size_t size) {
+    { t.allocate(size) } -> std::same_as<uint8_t *>;
+    { t.deallocate(pointer, size) } -> std::same_as<void>;
+  };
+}  // namespace teachos::arch::memory::heap
+
+#endif  // TEACHOS_ARCH_X86_64_MEMORY_HEAP_CONCEPT_HPP
\ No newline at end of file
diff --git a/arch/x86_64/include/arch/memory/main.hpp b/arch/x86_64/include/arch/memory/main.hpp
new file mode 100644
index 0000000..e166285
--- /dev/null
+++ b/arch/x86_64/include/arch/memory/main.hpp
@@ -0,0 +1,13 @@
+#ifndef TEACHOS_ARCH_X86_64_MEMORY_MAIN_HPP
+#define TEACHOS_ARCH_X86_64_MEMORY_MAIN_HPP
+
+namespace teachos::arch::memory
+{
+  /**
+   * @brief
+   *
+   */
+  auto initialize_memory_management() -> void;
+}  // namespace teachos::arch::memory
+
+#endif
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 4687209..1b2aaed 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
@@ -98,7 +98,7 @@ namespace teachos::arch::memory::paging
      * @see map_page_to_frame
      */
     template<allocator::FrameAllocator T>
-    auto map_next_free_page_to_frame(T & allocator, virtual_page page, std::bitset<64U> flags) -> void
+    auto map_page_to_next_free_frame(T & allocator, virtual_page page, std::bitset<64U> flags) -> void
     {
       auto const frame = allocator.allocate_frame();
       exception_handling::assert(frame.has_value(), "[Page mapper] Out of memory exception");
diff --git a/arch/x86_64/scripts/kernel.ld b/arch/x86_64/scripts/kernel.ld
index e9d245f..c3eea9c 100644
--- a/arch/x86_64/scripts/kernel.ld
+++ b/arch/x86_64/scripts/kernel.ld
@@ -60,9 +60,8 @@ SECTIONS
   }
 
   /***************************************************************************
-   * Now it is time to load the 64-bit kernel code. We virtually load it into
-   * the upper 2GiB, while adjusting the linear load address appropriately. We
-   * also make sure to align the loaded data onto a page boundary.
+   * Now it is time to load the 64-bit kernel code. We
+   * make sure to align the loaded data onto a page boundary.
    ***************************************************************************/
   .init ALIGN(4K) : AT(ADDR (.init))
   {
diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index 8a73630..cbd6e68 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -1,16 +1,8 @@
 #include "arch/kernel/main.hpp"
 
-#include "arch/exception_handling/assert.hpp"
-#include "arch/memory/allocator/area_frame_allocator.hpp"
-#include "arch/memory/cpu/control_register.hpp"
-#include "arch/memory/cpu/msr.hpp"
-#include "arch/memory/multiboot/reader.hpp"
-#include "arch/memory/paging/kernel_mapper.hpp"
-#include "arch/memory/paging/temporary_page.hpp"
+#include "arch/memory/main.hpp"
 #include "arch/video/vga/text.hpp"
 
-#include <algorithm>
-
 namespace teachos::arch::kernel
 {
   auto main() -> void
@@ -19,61 +11,21 @@ namespace teachos::arch::kernel
     video::vga::text::cursor(false);
     video::vga::text::write("TeachOS is starting up...", video::vga::text::common_attributes::green_on_black);
 
-    auto const memory_information = memory::multiboot::read_multiboot2();
-    memory::allocator::area_frame_allocator allocator(memory_information);
+    memory::initialize_memory_management();
+
+    // heap::bump_allocator heap_allocator{memory::heap::HEAP_START, heap::HEAP_START + memory::heap::HEAP_SIZE};
+    // auto test = heap_allocator.allocate(1024);
 
-    memory::cpu::set_cr2_bit(memory::cpu::cr2_flags::WRITE_PROTECT);
-    memory::cpu::set_efer_bit(memory::cpu::efer_flags::NXE);
+    // auto test2 = new (test) multiboot::memory_information{};
 
-    memory::paging::kernel_mapper kernel(allocator, memory_information);
-    auto & active_table = kernel.remap_kernel();
-    auto x = active_table.active_handle.next_table(0);
-    auto y = x.value().next_table(0);
-    auto z = y.value().next_table(0);
-    if (z.has_value())
-    {
-      video::vga::text::write("Kernel remapping successfull", video::vga::text::common_attributes::green_on_black);
-    }
+    // if (test || test2)
+    // {
+    //   video::vga::text::write("Kernel remapping successfull", video::vga::text::common_attributes::green_on_black);
+    // }
 
     // TODO: Why is identity mapping multiboot2 information structure with new kernel not required and
     // allocator.allocate_frame still works?
     // TODO: Fix unmapping old level 4 page table and turn it into guard page, use Stack Probes for stack allocation if
     // possible.
-
-    // TODO: Map heap virtual pages with active table
-
-    /*
-        size_t address = 42 * memory::paging::PAGE_TABLE_ENTRY_COUNT * memory::paging::PAGE_TABLE_ENTRY_COUNT *
-                         memory::allocator::PAGE_FRAME_SIZE;  // 42th P3 entry
-        auto const page = memory::paging::virtual_page::containing_address(address);
-        memory::paging::map_next_free_page_to_frame(allocator, page, 0U);
-        auto optional_frame = memory::paging::translate_page(page);
-        video::vga::text::newline();
-        video::vga::text::write("Mapped physical frame: ", video::vga::text::common_attributes::green_on_black);
-        video::vga::text::write_number(optional_frame.value().frame_number,
-                                       video::vga::text::common_attributes::green_on_black);
-        video::vga::text::write(" to virtual page: ", video::vga::text::common_attributes::green_on_black);
-        video::vga::text::write_number(page.page_number, video::vga::text::common_attributes::green_on_black);
-
-        memory::paging::unmap_page(allocator, page);
-        video::vga::text::newline();
-        video::vga::text::write("Unapped virtual page from physical frame: ",
-                                video::vga::text::common_attributes::green_on_black);
-        optional_frame = memory::paging::translate_page(page);
-        exception_handling::assert(!optional_frame.has_value(), "[Main] Ummapping failed");
-        video::vga::text::write_number(page.page_number, video::vga::text::common_attributes::green_on_black);
-
-        auto last_allocated = allocator.allocate_frame();
-        auto allocated = last_allocated;
-        do
-        {
-          last_allocated = allocated;
-          allocated = allocator.allocate_frame();
-        } while (allocated);
-        video::vga::text::newline();
-        video::vga::text::write("Allocated Frames: ", video::vga::text::common_attributes::green_on_black);
-        video::vga::text::write_number(last_allocated.value().frame_number,
-                                       video::vga::text::common_attributes::green_on_black);
-    */
   }
 }  // namespace teachos::arch::kernel
diff --git a/arch/x86_64/src/memory/heap/allocator.cpp b/arch/x86_64/src/memory/heap/allocator.cpp
new file mode 100644
index 0000000..c9ddd78
--- /dev/null
+++ b/arch/x86_64/src/memory/heap/allocator.cpp
@@ -0,0 +1,27 @@
+#include "arch/memory/heap/allocator.hpp"
+
+#include "arch/exception_handling/assert.hpp"
+
+namespace teachos::arch::memory::heap
+{
+  auto bump_allocator::allocate(std::size_t size) -> void *
+  {
+    // Uses some sort of alignment orignally:
+    // https://github.com/phil-opp/blog_os/blob/7f6576c9dc34e360b81236c54c25c7827fd6a2df/src/memory/heap_allocator.rs#L24
+    auto alloc_start = next;
+    auto alloc_end = next + size;
+
+    arch::exception_handling::assert(alloc_end <= heap_end, "[Heap Allocator] Out of memory!");
+
+    next = alloc_end;
+    return reinterpret_cast<void *>(alloc_start);
+  }
+
+  auto bump_allocator::deallocate(uint8_t * pointer, std::size_t size) -> void
+  {
+    // Memory leak
+    if (pointer || size)
+    {
+    }
+  }
+}  // namespace teachos::arch::memory::heap
\ No newline at end of file
diff --git a/arch/x86_64/src/memory/main.cpp b/arch/x86_64/src/memory/main.cpp
new file mode 100644
index 0000000..ce07115
--- /dev/null
+++ b/arch/x86_64/src/memory/main.cpp
@@ -0,0 +1,47 @@
+#include "arch/memory/main.hpp"
+
+#include "arch/exception_handling/assert.hpp"
+#include "arch/memory/allocator/area_frame_allocator.hpp"
+#include "arch/memory/cpu/control_register.hpp"
+#include "arch/memory/cpu/msr.hpp"
+#include "arch/memory/heap/allocator.hpp"
+#include "arch/memory/paging/active_page_table.hpp"
+#include "arch/memory/paging/kernel_mapper.hpp"
+
+namespace teachos::arch::memory
+{
+  namespace
+  {
+    auto remap_heap(allocator::area_frame_allocator allocator, paging::active_page_table & active_table) -> void
+    {
+      auto heap_start_page = paging::virtual_page::containing_address(memory::heap::HEAP_START);
+      auto heap_end_page =
+          paging::virtual_page::containing_address(memory::heap::HEAP_START + memory::heap::HEAP_SIZE - 1);
+
+      for (auto i = heap_start_page.page_number; i <= heap_end_page.page_number; i++)
+      {
+        active_table.map_page_to_next_free_frame(allocator, paging::virtual_page{i}, paging::entry::WRITABLE);
+      }
+    }
+  }  // namespace
+
+  auto initialize_memory_management() -> void
+  {
+    static bool has_been_called = false;
+    arch::exception_handling::assert(!has_been_called,
+                                     "[Initialization] Memory management has already been initialized");
+    has_been_called = true;
+
+    auto const memory_information = multiboot::read_multiboot2();
+    allocator::area_frame_allocator allocator(memory_information);
+
+    cpu::set_cr2_bit(memory::cpu::cr2_flags::WRITE_PROTECT);
+    cpu::set_efer_bit(memory::cpu::efer_flags::NXE);
+
+    paging::kernel_mapper kernel(allocator, memory_information);
+    auto & active_table = kernel.remap_kernel();
+    video::vga::text::write("Kernel remapping successfull", video::vga::text::common_attributes::green_on_black);
+
+    remap_heap(allocator, active_table);
+  }
+}  // namespace teachos::arch::memory
\ No newline at end of file