1 files changed, 76 insertions, 0 deletions
diff --git a/arch/x86/mm/debug_pagetables.c b/arch/x86/mm/debug_pagetables.c
new file mode 100644
index 000000000..092ea436c
--- /dev/null
+++ b/arch/x86/mm/debug_pagetables.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/debugfs.h>
+#include <linux/efi.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/pgtable.h>
+
+static int ptdump_show(struct seq_file *m, void *v)
+{
+	ptdump_walk_pgd_level_debugfs(m, &init_mm, false);
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(ptdump);
+
+static int ptdump_curknl_show(struct seq_file *m, void *v)
+{
+	if (current->mm->pgd)
+		ptdump_walk_pgd_level_debugfs(m, current->mm, false);
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(ptdump_curknl);
+
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+static int ptdump_curusr_show(struct seq_file *m, void *v)
+{
+	if (current->mm->pgd)
+		ptdump_walk_pgd_level_debugfs(m, current->mm, true);
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(ptdump_curusr);
+#endif
+
+#if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
+static int ptdump_efi_show(struct seq_file *m, void *v)
+{
+	if (efi_mm.pgd)
+		ptdump_walk_pgd_level_debugfs(m, &efi_mm, false);
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(ptdump_efi);
+#endif
+
+static struct dentry *dir;
+
+static int __init pt_dump_debug_init(void)
+{
+	dir = debugfs_create_dir("page_tables", NULL);
+
+	debugfs_create_file("kernel", 0400, dir, NULL, &ptdump_fops);
+	debugfs_create_file("current_kernel", 0400, dir, NULL,
+			    &ptdump_curknl_fops);
+
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+	debugfs_create_file("current_user", 0400, dir, NULL,
+			    &ptdump_curusr_fops);
+#endif
+#if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
+	debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops);
+#endif
+	return 0;
+}
+
+static void __exit pt_dump_debug_exit(void)
+{
+	debugfs_remove_recursive(dir);
+}
+
+module_init(pt_dump_debug_init);
+module_exit(pt_dump_debug_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
+MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");