arch/x86/mm/debug_pagetables.c

   1 #include <linux/debugfs.h>
   2 #include <linux/efi.h>
   3 #include <linux/module.h>
   4 #include <linux/seq_file.h>
   5 #include <asm/pgtable.h>
   6
   7 static int ptdump_show(struct seq_file *m, void *v)
   8 {
   9         ptdump_walk_pgd_level_debugfs(m, NULL, false);
  10         return 0;
  11 }
  12
  13 DEFINE_SHOW_ATTRIBUTE(ptdump);
  14
  15 static int ptdump_curknl_show(struct seq_file *m, void *v)
  16 {
  17         if (current->mm->pgd) {
  18                 down_read(&current->mm->mmap_sem);
  19                 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, false);
  20                 up_read(&current->mm->mmap_sem);
  21         }
  22         return 0;
  23 }
  24
  25 DEFINE_SHOW_ATTRIBUTE(ptdump_curknl);
  26
  27 #ifdef CONFIG_PAGE_TABLE_ISOLATION
  28 static struct dentry *pe_curusr;
  29
  30 static int ptdump_curusr_show(struct seq_file *m, void *v)
  31 {
  32         if (current->mm->pgd) {
  33                 down_read(&current->mm->mmap_sem);
  34                 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true);
  35                 up_read(&current->mm->mmap_sem);
  36         }
  37         return 0;
  38 }
  39
  40 DEFINE_SHOW_ATTRIBUTE(ptdump_curusr);
  41 #endif
  42
  43 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
  44 static struct dentry *pe_efi;
  45
  46 static int ptdump_efi_show(struct seq_file *m, void *v)
  47 {
  48         if (efi_mm.pgd)
  49                 ptdump_walk_pgd_level_debugfs(m, efi_mm.pgd, false);
  50         return 0;
  51 }
  52
  53 DEFINE_SHOW_ATTRIBUTE(ptdump_efi);
  54 #endif
  55
  56 static struct dentry *dir, *pe_knl, *pe_curknl;
  57
  58 static int __init pt_dump_debug_init(void)
  59 {
  60         dir = debugfs_create_dir("page_tables", NULL);
  61         if (!dir)
  62                 return -ENOMEM;
  63
  64         pe_knl = debugfs_create_file("kernel", 0400, dir, NULL,
  65                                      &ptdump_fops);
  66         if (!pe_knl)
  67                 goto err;
  68
  69         pe_curknl = debugfs_create_file("current_kernel", 0400,
  70                                         dir, NULL, &ptdump_curknl_fops);
  71         if (!pe_curknl)
  72                 goto err;
  73
  74 #ifdef CONFIG_PAGE_TABLE_ISOLATION
  75         pe_curusr = debugfs_create_file("current_user", 0400,
  76                                         dir, NULL, &ptdump_curusr_fops);
  77         if (!pe_curusr)
  78                 goto err;
  79 #endif
  80
  81 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
  82         pe_efi = debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops);
  83         if (!pe_efi)
  84                 goto err;
  85 #endif
  86
  87         return 0;
  88 err:
  89         debugfs_remove_recursive(dir);
  90         return -ENOMEM;
  91 }
  92
  93 static void __exit pt_dump_debug_exit(void)
  94 {
  95         debugfs_remove_recursive(dir);
  96 }
  97
  98 module_init(pt_dump_debug_init);
  99 module_exit(pt_dump_debug_exit);
 100 MODULE_LICENSE("GPL");
 101 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
 102 MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");