root/arch/x86/mm/debug_pagetables.c

DEFINITIONS

1. ptdump_show
2. ptdump_curknl_show
3. ptdump_curusr_show
4. ptdump_efi_show
5. pt_dump_debug_init
6. pt_dump_debug_exit

   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(&current->mm->mmap_sem);
  20                 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, false);
  21                 up_read(&current->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(&current->mm->mmap_sem);
  33                 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true);
  34                 up_read(&current->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");