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