MemoryManager: Add an unmap_weak_and_free_vm() helper function

This function mirrors unmap_owned_and_free_vm(), but using weak unmapping (does not free the underlying physical memory)

kernel/src/memory/MemoryManager.cpp

@@ -309,6 +309,15 @@ namespace MemoryManager
         return {};
     }
 
+    Result<void> unmap_weak_and_free_vm(u64 virt, usize count)
+    {
+        CHECK_PAGE_ALIGNED(virt);
+
+        KernelVM::free_several_pages(virt, count);
+
+        return unmap_weak(virt, count);
+    }
+
     Result<void> remap_unaligned(u64 address, usize count, int flags)
     {
         if (!is_aligned<ARCH_PAGE_SIZE>(address)) count++;

kernel/src/memory/MemoryManager.h

@@ -30,6 +30,7 @@ namespace MemoryManager
     Result<void> unmap_owned(u64 virt, usize count);
     Result<void> unmap_owned_and_free_vm(u64 virt, usize count);
     Result<void> unmap_weak(u64 virt, usize count);
+    Result<void> unmap_weak_and_free_vm(u64 virt, usize count);
 
     usize free();
     usize used();