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
  7static int ptdump_show(struct seq_file *m, void *v)
  8{
  9	ptdump_walk_pgd_level_debugfs(m, NULL, false);
 10	return 0;
 11}
 12
 13static int ptdump_open(struct inode *inode, struct file *filp)
 14{
 15	return single_open(filp, ptdump_show, NULL);
 16}
 17
 18static 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
 26static 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
 36static int ptdump_open_curknl(struct inode *inode, struct file *filp)
 37{
 38	return single_open(filp, ptdump_show_curknl, NULL);
 39}
 40
 41static 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
 50static struct dentry *pe_curusr;
 51
 52static 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
 62static int ptdump_open_curusr(struct inode *inode, struct file *filp)
 63{
 64	return single_open(filp, ptdump_show_curusr, NULL);
 65}
 66
 67static 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)
 77static struct dentry *pe_efi;
 78
 79static 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
 86static int ptdump_open_efi(struct inode *inode, struct file *filp)
 87{
 88	return single_open(filp, ptdump_show_efi, NULL);
 89}
 90
 91static 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
100static struct dentry *dir, *pe_knl, *pe_curknl;
101
102static 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;
132err:
133	debugfs_remove_recursive(dir);
134	return -ENOMEM;
135}
136
137static void __exit pt_dump_debug_exit(void)
138{
139	debugfs_remove_recursive(dir);
140}
141
142module_init(pt_dump_debug_init);
143module_exit(pt_dump_debug_exit);
144MODULE_LICENSE("GPL");
145MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
146MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");