1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/debugfs.h> 3 #include <linux/efi.h> 4 #include <linux/module.h> 5 #include <linux/seq_file.h> 6 #include <linux/pgtable.h> 7 8 static int ptdump_show(struct seq_file *m, void *v) 9 { 10 ptdump_walk_pgd_level_debugfs(m, &init_mm, false); 11 return 0; 12 } 13 14 DEFINE_SHOW_ATTRIBUTE(ptdump); 15 16 static int ptdump_curknl_show(struct seq_file *m, void *v) 17 { 18 if (current->mm->pgd) 19 ptdump_walk_pgd_level_debugfs(m, current->mm, false); 20 return 0; 21 } 22 23 DEFINE_SHOW_ATTRIBUTE(ptdump_curknl); 24 25 #ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION 26 static int ptdump_curusr_show(struct seq_file *m, void *v) 27 { 28 if (current->mm->pgd) 29 ptdump_walk_pgd_level_debugfs(m, current->mm, true); 30 return 0; 31 } 32 33 DEFINE_SHOW_ATTRIBUTE(ptdump_curusr); 34 #endif 35 36 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64) 37 static int ptdump_efi_show(struct seq_file *m, void *v) 38 { 39 if (efi_mm.pgd) 40 ptdump_walk_pgd_level_debugfs(m, &efi_mm, false); 41 return 0; 42 } 43 44 DEFINE_SHOW_ATTRIBUTE(ptdump_efi); 45 #endif 46 47 static struct dentry *dir; 48 49 static int __init pt_dump_debug_init(void) 50 { 51 dir = debugfs_create_dir("page_tables", NULL); 52 53 debugfs_create_file("kernel", 0400, dir, NULL, &ptdump_fops); 54 debugfs_create_file("current_kernel", 0400, dir, NULL, 55 &ptdump_curknl_fops); 56 57 #ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION 58 debugfs_create_file("current_user", 0400, dir, NULL, 59 &ptdump_curusr_fops); 60 #endif 61 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64) 62 debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops); 63 #endif 64 return 0; 65 } 66 67 static void __exit pt_dump_debug_exit(void) 68 { 69 debugfs_remove_recursive(dir); 70 } 71 72 module_init(pt_dump_debug_init); 73 module_exit(pt_dump_debug_exit); 74 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>"); 75 MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables"); 76