x86_64/MMU: Map the physical address space using huge pages

kernel/src/arch/x86_64/MMU.cpp

@@ -278,9 +278,9 @@ namespace MMU
 
         const u64 physical_memory_size = highest_entry.address() + highest_entry.size();
 
-        // FIXME: Do this using 2MiB huge pages.
+        check(physical_memory_size % ARCH_HUGE_PAGE_SIZE == 0);
-        MemoryManager::map_frames_at(physical_memory_base, 0, physical_memory_size / ARCH_PAGE_SIZE,
+        MemoryManager::map_huge_frames_at(physical_memory_base, 0, physical_memory_size / ARCH_HUGE_PAGE_SIZE,
-                                     MMU::ReadWrite | MMU::NoExecute);
+                                          MMU::ReadWrite | MMU::NoExecute);
 
         g_physical_mapping_base = physical_memory_base;
 

kernel/src/memory/MemoryManager.cpp

@@ -213,6 +213,29 @@ namespace MemoryManager
         return {};
     }
 
+    Result<void> map_huge_frames_at(u64 virt, u64 phys, usize count, int flags)
+    {
+        CHECK_PAGE_ALIGNED(virt);
+        CHECK_PAGE_ALIGNED(phys);
+
+        usize pages_mapped = 0;
+
+        // Let's clean up after ourselves if we fail.
+        auto guard = make_scope_guard([=, &pages_mapped] { unmap_weak_huge(virt, pages_mapped); });
+
+        while (pages_mapped < count)
+        {
+            TRY(MMU::map(virt, phys, flags, MMU::UseHugePages::Yes));
+            virt += ARCH_HUGE_PAGE_SIZE;
+            phys += ARCH_HUGE_PAGE_SIZE;
+            pages_mapped++;
+        }
+
+        guard.deactivate();
+
+        return {};
+    }
+
     Result<u64> alloc_at(u64 virt, usize count, int flags)
     {
         CHECK_PAGE_ALIGNED(virt);
@@ -322,6 +345,19 @@ namespace MemoryManager
         return {};
     }
 
+    Result<void> unmap_weak_huge(u64 virt, usize count)
+    {
+        CHECK_PAGE_ALIGNED(virt);
+
+        while (count--)
+        {
+            TRY(MMU::unmap(virt));
+            virt += ARCH_HUGE_PAGE_SIZE;
+        }
+
+        return {};
+    }
+
     Result<void> unmap_weak_and_free_vm(u64 virt, usize count)
     {
         CHECK_PAGE_ALIGNED(virt);

kernel/src/memory/MemoryManager.h

@@ -53,6 +53,7 @@ namespace MemoryManager
     }
 
     Result<void> map_frames_at(u64 virt, u64 phys, usize count, int flags);
+    Result<void> map_huge_frames_at(u64 virt, u64 phys, usize count, int flags);
 
     Result<u64> alloc_at(u64 virt, usize count, int flags);
     Result<u64> alloc_for_kernel(usize count, int flags);
@@ -64,6 +65,8 @@ namespace MemoryManager
     Result<void> unmap_weak(u64 virt, usize count);
     Result<void> unmap_weak_and_free_vm(u64 virt, usize count);
 
+    Result<void> unmap_weak_huge(u64 virt, usize count);
+
     usize free();
     usize used();
     usize reserved();