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
ptdump_show(struct seq_file * m,void * v)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
ptdump_open(struct inode * inode,struct file * filp)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
ptdump_show_curknl(struct seq_file * m,void * v)26 static int ptdump_show_curknl(struct seq_file *m, void *v)
27 {
28 if (current->mm->pgd) {
29 down_read(¤t->mm->mmap_sem);
30 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, false);
31 up_read(¤t->mm->mmap_sem);
32 }
33 return 0;
34 }
35
ptdump_open_curknl(struct inode * inode,struct file * filp)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
ptdump_show_curusr(struct seq_file * m,void * v)52 static int ptdump_show_curusr(struct seq_file *m, void *v)
53 {
54 if (current->mm->pgd) {
55 down_read(¤t->mm->mmap_sem);
56 ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true);
57 up_read(¤t->mm->mmap_sem);
58 }
59 return 0;
60 }
61
ptdump_open_curusr(struct inode * inode,struct file * filp)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
ptdump_show_efi(struct seq_file * m,void * v)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
ptdump_open_efi(struct inode * inode,struct file * filp)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
pt_dump_debug_init(void)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
pt_dump_debug_exit(void)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");
147
