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 <asm/pgtable.h> 7 8 static int ptdump_show(struct seq_file *m, void *v) 9 { 10 ptdump_walk_pgd_level_debugfs(m, NULL, 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 down_read(¤t->mm->mmap_sem); 20 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, false); 21 up_read(¤t->mm->mmap_sem); 22 } 23 return 0; 24 } 25 26 DEFINE_SHOW_ATTRIBUTE(ptdump_curknl); 27 28 #ifdef CONFIG_PAGE_TABLE_ISOLATION 29 static struct dentry *pe_curusr; 30 31 static int ptdump_curusr_show(struct seq_file *m, void *v) 32 { 33 if (current->mm->pgd) { 34 down_read(¤t->mm->mmap_sem); 35 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true); 36 up_read(¤t->mm->mmap_sem); 37 } 38 return 0; 39 } 40 41 DEFINE_SHOW_ATTRIBUTE(ptdump_curusr); 42 #endif 43 44 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64) 45 static struct dentry *pe_efi; 46 47 static int ptdump_efi_show(struct seq_file *m, void *v) 48 { 49 if (efi_mm.pgd) 50 ptdump_walk_pgd_level_debugfs(m, efi_mm.pgd, false); 51 return 0; 52 } 53 54 DEFINE_SHOW_ATTRIBUTE(ptdump_efi); 55 #endif 56 57 static struct dentry *dir, *pe_knl, *pe_curknl; 58 59 static int __init pt_dump_debug_init(void) 60 { 61 dir = debugfs_create_dir("page_tables", NULL); 62 if (!dir) 63 return -ENOMEM; 64 65 pe_knl = debugfs_create_file("kernel", 0400, dir, NULL, 66 &ptdump_fops); 67 if (!pe_knl) 68 goto err; 69 70 pe_curknl = debugfs_create_file("current_kernel", 0400, 71 dir, NULL, &ptdump_curknl_fops); 72 if (!pe_curknl) 73 goto err; 74 75 #ifdef CONFIG_PAGE_TABLE_ISOLATION 76 pe_curusr = debugfs_create_file("current_user", 0400, 77 dir, NULL, &ptdump_curusr_fops); 78 if (!pe_curusr) 79 goto err; 80 #endif 81 82 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64) 83 pe_efi = debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops); 84 if (!pe_efi) 85 goto err; 86 #endif 87 88 return 0; 89 err: 90 debugfs_remove_recursive(dir); 91 return -ENOMEM; 92 } 93 94 static void __exit pt_dump_debug_exit(void) 95 { 96 debugfs_remove_recursive(dir); 97 } 98 99 module_init(pt_dump_debug_init); 100 module_exit(pt_dump_debug_exit); 101 MODULE_LICENSE("GPL"); 102 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>"); 103 MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables"); 104