[BOOT:MM] More work on memory manager

BOOT/ENVIRON/LIB/EFI/efimm.c

@@ -0,0 +1,56 @@
+/*++
+
+Copyright (c) 2024, Quinn Stephens.
+Provided under the BSD 3-Clause license.
+
+Module Name:
+
+   efimm.c
+
+Abstract:
+
+   Provides EFI memory manager routines.
+
+--*/
+
+#include "bootmgr.h"
+#include "efi.h"
+#include "mm.h"
+
+NTSTATUS
+MmFwGetMemoryMap (
+   IN OUT PMEMORY_DESCRIPTOR_LIST Mdl,
+   IN ULONG Flags
+   )
+
+/*++
+
+Routine Description:
+
+    Converts an NT status code into an EFI status code.
+
+Arguments:
+
+    Status - The NT status code to be converted.
+
+Return Value:
+
+    STATUS_SUCCESS if successful,
+    STATUS_INVALID_PARAMETER if Mdl is invalid.
+
+--*/
+
+{
+    (VOID)Flags;
+
+    //
+    // Make sure Mdl is valid.
+    //
+    if (Mdl == NULL) {
+        return STATUS_INVALID_PARAMETER;
+    }
+
+    MmMdFreeList(Mdl);
+
+    return STATUS_SUCCESS;
+}