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 int ptdump_curusr_show(struct seq_file *m, void *v) 30 { 31 if (current->mm->pgd) { 32 down_read(¤t->mm->mmap_sem); 33 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true); 34 up_read(¤t->mm->mmap_sem); 35 } 36 return 0; 37 } 38 39 DEFINE_SHOW_ATTRIBUTE(ptdump_curusr); 40 #endif 41 42 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64) 43 static int ptdump_efi_show(struct seq_file *m, void *v) 44 { 45 if (efi_mm.pgd) 46 ptdump_walk_pgd_level_debugfs(m, efi_mm.pgd, false); 47 return 0; 48 } 49 50 DEFINE_SHOW_ATTRIBUTE(ptdump_efi); 51 #endif 52 53 static struct dentry *dir; 54 55 static int __init pt_dump_debug_init(void) 56 { 57 dir = debugfs_create_dir("page_tables", NULL); 58 59 debugfs_create_file("kernel", 0400, dir, NULL, &ptdump_fops); 60 debugfs_create_file("current_kernel", 0400, dir, NULL, 61 &ptdump_curknl_fops); 62 63 #ifdef CONFIG_PAGE_TABLE_ISOLATION 64 debugfs_create_file("current_user", 0400, dir, NULL, 65 &ptdump_curusr_fops); 66 #endif 67 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64) 68 debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops); 69 #endif 70 return 0; 71 } 72 73 static void __exit pt_dump_debug_exit(void) 74 { 75 debugfs_remove_recursive(dir); 76 } 77 78 module_init(pt_dump_debug_init); 79 module_exit(pt_dump_debug_exit); 80 MODULE_LICENSE("GPL"); 81 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>"); 82 MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables"); 83