make frame_allocator and active_page_table statically available

6 files changed, 60 insertions, 27 deletions

diff --git a/arch/x86_64/include/arch/memory/allocator/area_frame_allocator.hpp b/arch/x86_64/include/arch/memory/allocator/area_frame_allocator.hpp
index 2244613..6cb5f56 100644
--- a/arch/x86_64/include/arch/memory/allocator/area_frame_allocator.hpp
+++ b/arch/x86_64/include/arch/memory/allocator/area_frame_allocator.hpp
@@ -15,9 +15,9 @@ namespace teachos::arch::memory::allocator
   struct area_frame_allocator
   {
     /**
-     * @brief Constructor
+     * @brief Constructor.
      *
-     * @param mem_info Structure containg all relevant information to map and allocate memory
+     * @param mem_info Structure containg all relevant information to map and allocate memory.
      */
     area_frame_allocator(multiboot::memory_information const & mem_info);
 
diff --git a/arch/x86_64/include/arch/memory/main.hpp b/arch/x86_64/include/arch/memory/main.hpp
index 164abbc..d51815f 100644
--- a/arch/x86_64/include/arch/memory/main.hpp
+++ b/arch/x86_64/include/arch/memory/main.hpp
@@ -1,8 +1,22 @@
 #ifndef TEACHOS_ARCH_X86_64_MEMORY_MAIN_HPP
 #define TEACHOS_ARCH_X86_64_MEMORY_MAIN_HPP
 
+#include "arch/memory/paging/page_entry.hpp"
+
+#include <cstdint>
+
 namespace teachos::arch::memory
 {
+
+  /**
+   * @brief Maps a heap section to a page.
+   *
+   * @param heap_start Start-address of the heap.
+   * @param heap_size Size of the heap.
+   * @param additional_flags Additional flags to apply to the page entry.
+   */
+  auto remap_heap(std::size_t heap_start, std::size_t heap_size, paging::entry::bitset additional_flags) -> void;
+
   /**
    * @brief Initializes memory management.
    *
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 7321548..756eeb1 100644
--- a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
+++ b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
@@ -38,7 +38,7 @@ namespace teachos::arch::memory::paging
      * inactive page table, that is not used by the CPU to ensure we are not changign memory that we are using. Because
      * remapping active kernel memory in the kernel wouldn't work.
      */
-    auto remap_kernel() -> active_page_table &
+    auto remap_kernel() -> void
     {
       // Set Page Global Enable bit
       auto cr4 = kernel::cpu::read_control_register(kernel::cpu::control_register::CR4);
@@ -57,7 +57,6 @@ namespace teachos::arch::memory::paging
       auto const old_level_4_page =
           virtual_page::containing_address(old_table.page_table_level_4_frame.start_address());
       active_table.unmap_page(allocator, old_level_4_page);
-      return active_table;
     }
 
   private:
diff --git a/arch/x86_64/src/context_switching/syscall/syscall_handler.cpp b/arch/x86_64/src/context_switching/syscall/syscall_handler.cpp
index b88f273..9ca03d9 100644
--- a/arch/x86_64/src/context_switching/syscall/syscall_handler.cpp
+++ b/arch/x86_64/src/context_switching/syscall/syscall_handler.cpp
@@ -2,6 +2,8 @@
 
 #include "arch/context_switching/syscall/main.hpp"
 #include "arch/exception_handling/panic.hpp"
+#include "arch/memory/heap/global_heap_allocator.hpp"
+#include "arch/memory/main.hpp"
 #include "arch/video/vga/text.hpp"
 
 namespace teachos::arch::context_switching::syscall
@@ -19,6 +21,10 @@ namespace teachos::arch::context_switching::syscall
 
     auto expand_user_heap() -> error
     {
+      // TODO: use actual addresses instead of this constant!
+      memory::remap_heap(memory::heap::USER_HEAP_SIZE + memory::heap::USER_HEAP_SIZE, memory::heap::USER_HEAP_SIZE,
+                         memory::paging::entry::USER_ACCESSIBLE);
+
       arguments args{};
       asm volatile("mov %[input], %%rdi"
                    : /* no output from call */
diff --git a/arch/x86_64/src/memory/heap/memory_block.cpp b/arch/x86_64/src/memory/heap/memory_block.cpp
index 446cd96..9f1fea8 100644
--- a/arch/x86_64/src/memory/heap/memory_block.cpp
+++ b/arch/x86_64/src/memory/heap/memory_block.cpp
@@ -6,6 +6,7 @@ namespace teachos::arch::memory::heap
 {
   memory_block::memory_block(std::size_t size, memory_block * next)
   {
+    // TODO: Figure out why this memset fails
     memset(static_cast<void *>(this), 0, size);
     this->size = size;
     this->next = next;
diff --git a/arch/x86_64/src/memory/main.cpp b/arch/x86_64/src/memory/main.cpp
index 4cdfa80..595cb0d 100644
--- a/arch/x86_64/src/memory/main.cpp
+++ b/arch/x86_64/src/memory/main.cpp
@@ -9,37 +9,47 @@
 #include "arch/memory/paging/active_page_table.hpp"
 #include "arch/memory/paging/kernel_mapper.hpp"
 
+#include <optional>
+
 namespace teachos::arch::memory
 {
   namespace
   {
-    template<allocator::FrameAllocator T>
-    auto create_frame_allocator(multiboot::memory_information const & memory_information) -> T
+    static std::optional<allocator::area_frame_allocator> frame_allocator;
+
+    auto create_frame_allocator(multiboot::memory_information const & memory_information)
+        -> allocator::area_frame_allocator
     {
-      return allocator::area_frame_allocator{memory_information};
+      frame_allocator.emplace(memory_information);
+      return frame_allocator.value();
     }
 
-    template<allocator::FrameAllocator T>
-    auto remap_heap(T & allocator, paging::active_page_table & active_table, bool is_user_heap = false) -> void
+    auto get_frame_allocator() -> allocator::area_frame_allocator
     {
-      auto const heap_start = is_user_heap ? heap::USER_HEAP_START : heap::KERNEL_HEAP_START;
-      auto const heap_size = is_user_heap ? heap::USER_HEAP_SIZE : heap::KERNEL_HEAP_SIZE;
+      exception_handling::assert(frame_allocator.has_value(), "[Memory main] Frame allocator has not been created yet");
+      return frame_allocator.value();
+    }
+  }  // namespace
+
+  auto remap_heap(std::size_t heap_start, std::size_t heap_size, paging::entry::bitset additional_flags = {}) -> void
+  {
+    auto allocator = get_frame_allocator();
+    decltype(auto) active_table = paging::active_page_table::create_or_get();
+    auto const start_page = paging::virtual_page::containing_address(heap_start);
+    auto const end_page = ++(paging::virtual_page::containing_address(heap_start + heap_size - 1));
 
-      auto const start_page = paging::virtual_page::containing_address(heap_start);
-      auto const end_page = ++(paging::virtual_page::containing_address(heap_start + heap_size - 1));
-      paging::page_container::iterator const begin{start_page};
-      paging::page_container::iterator const end{end_page};
-      paging::page_container const pages{begin, end};
+    paging::page_container::iterator const begin{start_page};
+    paging::page_container::iterator const end{end_page};
+    paging::page_container const pages{begin, end};
 
-      constexpr auto base_flags = paging::entry::WRITABLE;
-      auto const flags = is_user_heap ? base_flags | paging::entry::USER_ACCESSIBLE : base_flags;
+    constexpr auto base_flags = paging::entry::WRITABLE;
+    auto const flags = base_flags | additional_flags;
 
-      for (auto const & page : pages)
-      {
-        active_table.map_page_to_next_free_frame(allocator, page, flags);
-      }
+    for (auto const & page : pages)
+    {
+      active_table.map_page_to_next_free_frame(allocator, page, flags);
     }
-  }  // namespace
+  }
 
   auto initialize_memory_management() -> void
   {
@@ -49,18 +59,21 @@ namespace teachos::arch::memory
     has_been_called = true;
 
     auto const memory_information = multiboot::read_multiboot2();
-    auto allocator = create_frame_allocator<allocator::area_frame_allocator>(memory_information);
+    auto allocator = create_frame_allocator(memory_information);
 
     kernel::cpu::set_cr0_bit(kernel::cpu::cr0_flags::WRITE_PROTECT);
     kernel::cpu::set_efer_bit(kernel::cpu::efer_flags::NXE);
 
     paging::kernel_mapper kernel(allocator, memory_information);
-    auto & active_table = kernel.remap_kernel();
+    kernel.remap_kernel();
     video::vga::text::write("Kernel remapping successful", video::vga::text::common_attributes::green_on_black);
     video::vga::text::newline();
 
-    remap_heap(allocator, active_table);        // Remap kernel heap
-    remap_heap(allocator, active_table, true);  // Remap user heap
+    // Remap kernel heap
+    remap_heap(heap::KERNEL_HEAP_START, heap::KERNEL_HEAP_SIZE);
+    // Remap user heap
+    remap_heap(heap::USER_HEAP_SIZE, heap::USER_HEAP_SIZE, paging::entry::USER_ACCESSIBLE);
+
     video::vga::text::write("Heap remapping successful", video::vga::text::common_attributes::green_on_black);
     video::vga::text::newline();
   }