1 /*
2 * Copyright (c) 2014, The Linux Foundation. All rights reserved.
3 * Debug helper to dump the current kernel pagetables of the system
4 * so that we can see what the various memory ranges are set to.
5 *
6 * Derived from x86 and arm implementation:
7 * (C) Copyright 2008 Intel Corporation
8 *
9 * Author: Arjan van de Ven <arjan@linux.intel.com>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; version 2
14 * of the License.
15 */
16 #include <linux/debugfs.h>
17 #include <linux/fs.h>
18 #include <linux/io.h>
19 #include <linux/mm.h>
20 #include <linux/sched.h>
21 #include <linux/seq_file.h>
22
23 #include <asm/fixmap.h>
24 #include <asm/pgtable.h>
25
26 #define LOWEST_ADDR (UL(0xffffffffffffffff) << VA_BITS)
27
28 struct addr_marker {
29 unsigned long start_address;
30 const char *name;
31 };
32
33 enum address_markers_idx {
34 VMALLOC_START_NR = 0,
35 VMALLOC_END_NR,
36 #ifdef CONFIG_SPARSEMEM_VMEMMAP
37 VMEMMAP_START_NR,
38 VMEMMAP_END_NR,
39 #endif
40 PCI_START_NR,
41 PCI_END_NR,
42 FIXADDR_START_NR,
43 FIXADDR_END_NR,
44 MODULES_START_NR,
45 MODUELS_END_NR,
46 KERNEL_SPACE_NR,
47 };
48
49 static struct addr_marker address_markers[] = {
50 { VMALLOC_START, "vmalloc() Area" },
51 { VMALLOC_END, "vmalloc() End" },
52 #ifdef CONFIG_SPARSEMEM_VMEMMAP
53 { 0, "vmemmap start" },
54 { 0, "vmemmap end" },
55 #endif
56 { (unsigned long) PCI_IOBASE, "PCI I/O start" },
57 { (unsigned long) PCI_IOBASE + SZ_16M, "PCI I/O end" },
58 { FIXADDR_START, "Fixmap start" },
59 { FIXADDR_TOP, "Fixmap end" },
60 { MODULES_VADDR, "Modules start" },
61 { MODULES_END, "Modules end" },
62 { PAGE_OFFSET, "Kernel Mapping" },
63 { -1, NULL },
64 };
65
66 struct pg_state {
67 struct seq_file *seq;
68 const struct addr_marker *marker;
69 unsigned long start_address;
70 unsigned level;
71 u64 current_prot;
72 };
73
74 struct prot_bits {
75 u64 mask;
76 u64 val;
77 const char *set;
78 const char *clear;
79 };
80
81 static const struct prot_bits pte_bits[] = {
82 {
83 .mask = PTE_USER,
84 .val = PTE_USER,
85 .set = "USR",
86 .clear = " ",
87 }, {
88 .mask = PTE_RDONLY,
89 .val = PTE_RDONLY,
90 .set = "ro",
91 .clear = "RW",
92 }, {
93 .mask = PTE_PXN,
94 .val = PTE_PXN,
95 .set = "NX",
96 .clear = "x ",
97 }, {
98 .mask = PTE_SHARED,
99 .val = PTE_SHARED,
100 .set = "SHD",
101 .clear = " ",
102 }, {
103 .mask = PTE_AF,
104 .val = PTE_AF,
105 .set = "AF",
106 .clear = " ",
107 }, {
108 .mask = PTE_NG,
109 .val = PTE_NG,
110 .set = "NG",
111 .clear = " ",
112 }, {
113 .mask = PTE_UXN,
114 .val = PTE_UXN,
115 .set = "UXN",
116 }, {
117 .mask = PTE_ATTRINDX_MASK,
118 .val = PTE_ATTRINDX(MT_DEVICE_nGnRnE),
119 .set = "DEVICE/nGnRnE",
120 }, {
121 .mask = PTE_ATTRINDX_MASK,
122 .val = PTE_ATTRINDX(MT_DEVICE_nGnRE),
123 .set = "DEVICE/nGnRE",
124 }, {
125 .mask = PTE_ATTRINDX_MASK,
126 .val = PTE_ATTRINDX(MT_DEVICE_GRE),
127 .set = "DEVICE/GRE",
128 }, {
129 .mask = PTE_ATTRINDX_MASK,
130 .val = PTE_ATTRINDX(MT_NORMAL_NC),
131 .set = "MEM/NORMAL-NC",
132 }, {
133 .mask = PTE_ATTRINDX_MASK,
134 .val = PTE_ATTRINDX(MT_NORMAL),
135 .set = "MEM/NORMAL",
136 }
137 };
138
139 struct pg_level {
140 const struct prot_bits *bits;
141 size_t num;
142 u64 mask;
143 };
144
145 static struct pg_level pg_level[] = {
146 {
147 }, { /* pgd */
148 .bits = pte_bits,
149 .num = ARRAY_SIZE(pte_bits),
150 }, { /* pud */
151 .bits = pte_bits,
152 .num = ARRAY_SIZE(pte_bits),
153 }, { /* pmd */
154 .bits = pte_bits,
155 .num = ARRAY_SIZE(pte_bits),
156 }, { /* pte */
157 .bits = pte_bits,
158 .num = ARRAY_SIZE(pte_bits),
159 },
160 };
161
dump_prot(struct pg_state * st,const struct prot_bits * bits,size_t num)162 static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
163 size_t num)
164 {
165 unsigned i;
166
167 for (i = 0; i < num; i++, bits++) {
168 const char *s;
169
170 if ((st->current_prot & bits->mask) == bits->val)
171 s = bits->set;
172 else
173 s = bits->clear;
174
175 if (s)
176 seq_printf(st->seq, " %s", s);
177 }
178 }
179
note_page(struct pg_state * st,unsigned long addr,unsigned level,u64 val)180 static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
181 u64 val)
182 {
183 static const char units[] = "KMGTPE";
184 u64 prot = val & pg_level[level].mask;
185
186 if (addr < LOWEST_ADDR)
187 return;
188
189 if (!st->level) {
190 st->level = level;
191 st->current_prot = prot;
192 st->start_address = addr;
193 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
194 } else if (prot != st->current_prot || level != st->level ||
195 addr >= st->marker[1].start_address) {
196 const char *unit = units;
197 unsigned long delta;
198
199 if (st->current_prot) {
200 seq_printf(st->seq, "0x%16lx-0x%16lx ",
201 st->start_address, addr);
202
203 delta = (addr - st->start_address) >> 10;
204 while (!(delta & 1023) && unit[1]) {
205 delta >>= 10;
206 unit++;
207 }
208 seq_printf(st->seq, "%9lu%c", delta, *unit);
209 if (pg_level[st->level].bits)
210 dump_prot(st, pg_level[st->level].bits,
211 pg_level[st->level].num);
212 seq_puts(st->seq, "\n");
213 }
214
215 if (addr >= st->marker[1].start_address) {
216 st->marker++;
217 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
218 }
219
220 st->start_address = addr;
221 st->current_prot = prot;
222 st->level = level;
223 }
224
225 if (addr >= st->marker[1].start_address) {
226 st->marker++;
227 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
228 }
229
230 }
231
walk_pte(struct pg_state * st,pmd_t * pmd,unsigned long start)232 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
233 {
234 pte_t *pte = pte_offset_kernel(pmd, 0);
235 unsigned long addr;
236 unsigned i;
237
238 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
239 addr = start + i * PAGE_SIZE;
240 note_page(st, addr, 4, pte_val(*pte));
241 }
242 }
243
walk_pmd(struct pg_state * st,pud_t * pud,unsigned long start)244 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
245 {
246 pmd_t *pmd = pmd_offset(pud, 0);
247 unsigned long addr;
248 unsigned i;
249
250 for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
251 addr = start + i * PMD_SIZE;
252 if (pmd_none(*pmd) || pmd_sect(*pmd) || pmd_bad(*pmd))
253 note_page(st, addr, 3, pmd_val(*pmd));
254 else
255 walk_pte(st, pmd, addr);
256 }
257 }
258
walk_pud(struct pg_state * st,pgd_t * pgd,unsigned long start)259 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
260 {
261 pud_t *pud = pud_offset(pgd, 0);
262 unsigned long addr;
263 unsigned i;
264
265 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
266 addr = start + i * PUD_SIZE;
267 if (pud_none(*pud) || pud_sect(*pud) || pud_bad(*pud))
268 note_page(st, addr, 2, pud_val(*pud));
269 else
270 walk_pmd(st, pud, addr);
271 }
272 }
273
walk_pgd(struct pg_state * st,struct mm_struct * mm,unsigned long start)274 static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start)
275 {
276 pgd_t *pgd = pgd_offset(mm, 0);
277 unsigned i;
278 unsigned long addr;
279
280 for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
281 addr = start + i * PGDIR_SIZE;
282 if (pgd_none(*pgd) || pgd_bad(*pgd))
283 note_page(st, addr, 1, pgd_val(*pgd));
284 else
285 walk_pud(st, pgd, addr);
286 }
287 }
288
ptdump_show(struct seq_file * m,void * v)289 static int ptdump_show(struct seq_file *m, void *v)
290 {
291 struct pg_state st = {
292 .seq = m,
293 .marker = address_markers,
294 };
295
296 walk_pgd(&st, &init_mm, LOWEST_ADDR);
297
298 note_page(&st, 0, 0, 0);
299 return 0;
300 }
301
ptdump_open(struct inode * inode,struct file * file)302 static int ptdump_open(struct inode *inode, struct file *file)
303 {
304 return single_open(file, ptdump_show, NULL);
305 }
306
307 static const struct file_operations ptdump_fops = {
308 .open = ptdump_open,
309 .read = seq_read,
310 .llseek = seq_lseek,
311 .release = single_release,
312 };
313
ptdump_init(void)314 static int ptdump_init(void)
315 {
316 struct dentry *pe;
317 unsigned i, j;
318
319 for (i = 0; i < ARRAY_SIZE(pg_level); i++)
320 if (pg_level[i].bits)
321 for (j = 0; j < pg_level[i].num; j++)
322 pg_level[i].mask |= pg_level[i].bits[j].mask;
323
324 address_markers[VMEMMAP_START_NR].start_address =
325 (unsigned long)virt_to_page(PAGE_OFFSET);
326 address_markers[VMEMMAP_END_NR].start_address =
327 (unsigned long)virt_to_page(high_memory);
328
329 pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
330 &ptdump_fops);
331 return pe ? 0 : -ENOMEM;
332 }
333 device_initcall(ptdump_init);
334