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 static int ptdump_open(struct inode *inode, struct file *filp)
  14 {
  15         return single_open(filp, ptdump_show, NULL);
  16 }
  17
  18 static const struct file_operations ptdump_fops = {
  19         .owner          = THIS_MODULE,
  20         .open           = ptdump_open,
  21         .read           = seq_read,
  22         .llseek         = seq_lseek,
  23         .release        = single_release,
  24 };
  25
  26 static int ptdump_show_curknl(struct seq_file *m, void *v)
  27 {
  28         if (current->mm->pgd) {
  29                 down_read(&current->mm->mmap_sem);
  30                 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, false);
  31                 up_read(&current->mm->mmap_sem);
  32         }
  33         return 0;
  34 }
  35
  36 static int ptdump_open_curknl(struct inode *inode, struct file *filp)
  37 {
  38         return single_open(filp, ptdump_show_curknl, NULL);
  39 }
  40
  41 static const struct file_operations ptdump_curknl_fops = {
  42         .owner          = THIS_MODULE,
  43         .open           = ptdump_open_curknl,
  44         .read           = seq_read,
  45         .llseek         = seq_lseek,
  46         .release        = single_release,
  47 };
  48
  49 #ifdef CONFIG_PAGE_TABLE_ISOLATION
  50 static struct dentry *pe_curusr;
  51
  52 static int ptdump_show_curusr(struct seq_file *m, void *v)
  53 {
  54         if (current->mm->pgd) {
  55                 down_read(&current->mm->mmap_sem);
  56                 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true);
  57                 up_read(&current->mm->mmap_sem);
  58         }
  59         return 0;
  60 }
  61
  62 static int ptdump_open_curusr(struct inode *inode, struct file *filp)
  63 {
  64         return single_open(filp, ptdump_show_curusr, NULL);
  65 }
  66
  67 static const struct file_operations ptdump_curusr_fops = {
  68         .owner          = THIS_MODULE,
  69         .open           = ptdump_open_curusr,
  70         .read           = seq_read,
  71         .llseek         = seq_lseek,
  72         .release        = single_release,
  73 };
  74 #endif
  75
  76 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
  77 static struct dentry *pe_efi;
  78
  79 static int ptdump_show_efi(struct seq_file *m, void *v)
  80 {
  81         if (efi_mm.pgd)
  82                 ptdump_walk_pgd_level_debugfs(m, efi_mm.pgd, false);
  83         return 0;
  84 }
  85
  86 static int ptdump_open_efi(struct inode *inode, struct file *filp)
  87 {
  88         return single_open(filp, ptdump_show_efi, NULL);
  89 }
  90
  91 static const struct file_operations ptdump_efi_fops = {
  92         .owner          = THIS_MODULE,
  93         .open           = ptdump_open_efi,
  94         .read           = seq_read,
  95         .llseek         = seq_lseek,
  96         .release        = single_release,
  97 };
  98 #endif
  99
 100 static struct dentry *dir, *pe_knl, *pe_curknl;
 101
 102 static int __init pt_dump_debug_init(void)
 103 {
 104         dir = debugfs_create_dir("page_tables", NULL);
 105         if (!dir)
 106                 return -ENOMEM;
 107
 108         pe_knl = debugfs_create_file("kernel", 0400, dir, NULL,
 109                                      &ptdump_fops);
 110         if (!pe_knl)
 111                 goto err;
 112
 113         pe_curknl = debugfs_create_file("current_kernel", 0400,
 114                                         dir, NULL, &ptdump_curknl_fops);
 115         if (!pe_curknl)
 116                 goto err;
 117
 118 #ifdef CONFIG_PAGE_TABLE_ISOLATION
 119         pe_curusr = debugfs_create_file("current_user", 0400,
 120                                         dir, NULL, &ptdump_curusr_fops);
 121         if (!pe_curusr)
 122                 goto err;
 123 #endif
 124
 125 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
 126         pe_efi = debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops);
 127         if (!pe_efi)
 128                 goto err;
 129 #endif
 130
 131         return 0;
 132 err:
 133         debugfs_remove_recursive(dir);
 134         return -ENOMEM;
 135 }
 136
 137 static void __exit pt_dump_debug_exit(void)
 138 {
 139         debugfs_remove_recursive(dir);
 140 }
 141
 142 module_init(pt_dump_debug_init);
 143 module_exit(pt_dump_debug_exit);
 144 MODULE_LICENSE("GPL");
 145 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
 146 MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");