--- a/src/gearsTools/lib/Gears/Context.pm	Thu Dec 05 10:59:27 2019 +0900
+++ b/src/gearsTools/lib/Gears/Context.pm	Wed Dec 11 17:10:43 2019 +0900
@@ -166,6 +166,18 @@
 sub tree2data_struct_str {
   my ($self, $dg_str) = @_;
   my $data_struct_str  = "";
+
+  #もとのxv6に登録されているものはcontext.hには定義を書かない
+  my $alread_defined_str = _already_defined_struct();
+  for my $str (sort keys %$dg_str) {
+    if (defined $alread_defined_str->{$str}) {
+      my $str_name = $alread_defined_str->{$str};
+      $data_struct_str .= "struct $str_name $str_name;\n";
+      delete $dg_str->{$str_name};
+    }
+  }
+
+  #定義されてないものはcontext.hに書くフォーマットに合わせておく
   for my $interface (sort keys %$dg_str) {
     $data_struct_str .= Gears::Util->h2context_str($dg_str->{$interface}->{elem});
     next unless ($dg_str->{$interface}->{impl});
@@ -221,4 +233,31 @@
   return \%res;
 }
 
+sub _already_defined_struct {
+  my @struct_list = qw/
+__jmp_buf_tag
+buf
+cbc_devsw
+context
+cpu
+devsw
+dinode
+dirent
+elfhdr
+file
+inode
+pipe
+proc
+proghdr
+spinlock
+stat
+superblock
+trapframe
+/;
+
+  my %def_hash;
+  map { $def_hash{$_} = $_} @struct_list;
+  return \%def_hash;
+}
+
 1;