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1/*
2 * Debug helper to dump the current kernel pagetables of the system
3 * so that we can see what the various memory ranges are set to.
4 *
5 * (C) Copyright 2008 Intel Corporation
6 *
7 * Author: Arjan van de Ven <arjan@linux.intel.com>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; version 2
12 * of the License.
13 */
14
15#include <linux/debugfs.h>
16#include <linux/mm.h>
17#include <linux/module.h>
18#include <linux/seq_file.h>
19
20#include <asm/pgtable.h>
21
22/*
23 * The dumper groups pagetable entries of the same type into one, and for
24 * that it needs to keep some state when walking, and flush this state
25 * when a "break" in the continuity is found.
26 */
27struct pg_state {
28 int level;
29 pgprot_t current_prot;
30 unsigned long start_address;
31 unsigned long current_address;
32 const struct addr_marker *marker;
33};
34
35struct addr_marker {
36 unsigned long start_address;
37 const char *name;
38};
39
40/* indices for address_markers; keep sync'd w/ address_markers below */
41enum address_markers_idx {
42 USER_SPACE_NR = 0,
43#ifdef CONFIG_X86_64
44 KERNEL_SPACE_NR,
45 LOW_KERNEL_NR,
46 VMALLOC_START_NR,
47 VMEMMAP_START_NR,
48 HIGH_KERNEL_NR,
49 MODULES_VADDR_NR,
50 MODULES_END_NR,
51#else
52 KERNEL_SPACE_NR,
53 VMALLOC_START_NR,
54 VMALLOC_END_NR,
55# ifdef CONFIG_HIGHMEM
56 PKMAP_BASE_NR,
57# endif
58 FIXADDR_START_NR,
59#endif
60};
61
62/* Address space markers hints */
63static struct addr_marker address_markers[] = {
64 { 0, "User Space" },
65#ifdef CONFIG_X86_64
66 { 0x8000000000000000UL, "Kernel Space" },
67 { PAGE_OFFSET, "Low Kernel Mapping" },
68 { VMALLOC_START, "vmalloc() Area" },
69 { VMEMMAP_START, "Vmemmap" },
70 { __START_KERNEL_map, "High Kernel Mapping" },
71 { MODULES_VADDR, "Modules" },
72 { MODULES_END, "End Modules" },
73#else
74 { PAGE_OFFSET, "Kernel Mapping" },
75 { 0/* VMALLOC_START */, "vmalloc() Area" },
76 { 0/*VMALLOC_END*/, "vmalloc() End" },
77# ifdef CONFIG_HIGHMEM
78 { 0/*PKMAP_BASE*/, "Persisent kmap() Area" },
79# endif
80 { 0/*FIXADDR_START*/, "Fixmap Area" },
81#endif
82 { -1, NULL } /* End of list */
83};
84
85/* Multipliers for offsets within the PTEs */
86#define PTE_LEVEL_MULT (PAGE_SIZE)
87#define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
88#define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
89#define PGD_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
90
91/*
92 * Print a readable form of a pgprot_t to the seq_file
93 */
94static void printk_prot(struct seq_file *m, pgprot_t prot, int level)
95{
96 pgprotval_t pr = pgprot_val(prot);
97 static const char * const level_name[] =
98 { "cr3", "pgd", "pud", "pmd", "pte" };
99
100 if (!pgprot_val(prot)) {
101 /* Not present */
102 seq_printf(m, " ");
103 } else {
104 if (pr & _PAGE_USER)
105 seq_printf(m, "USR ");
106 else
107 seq_printf(m, " ");
108 if (pr & _PAGE_RW)
109 seq_printf(m, "RW ");
110 else
111 seq_printf(m, "ro ");
112 if (pr & _PAGE_PWT)
113 seq_printf(m, "PWT ");
114 else
115 seq_printf(m, " ");
116 if (pr & _PAGE_PCD)
117 seq_printf(m, "PCD ");
118 else
119 seq_printf(m, " ");
120
121 /* Bit 9 has a different meaning on level 3 vs 4 */
122 if (level <= 3) {
123 if (pr & _PAGE_PSE)
124 seq_printf(m, "PSE ");
125 else
126 seq_printf(m, " ");
127 } else {
128 if (pr & _PAGE_PAT)
129 seq_printf(m, "pat ");
130 else
131 seq_printf(m, " ");
132 }
133 if (pr & _PAGE_GLOBAL)
134 seq_printf(m, "GLB ");
135 else
136 seq_printf(m, " ");
137 if (pr & _PAGE_NX)
138 seq_printf(m, "NX ");
139 else
140 seq_printf(m, "x ");
141 }
142 seq_printf(m, "%s\n", level_name[level]);
143}
144
145/*
146 * On 64 bits, sign-extend the 48 bit address to 64 bit
147 */
148static unsigned long normalize_addr(unsigned long u)
149{
150#ifdef CONFIG_X86_64
151 return (signed long)(u << 16) >> 16;
152#else
153 return u;
154#endif
155}
156
157/*
158 * This function gets called on a break in a continuous series
159 * of PTE entries; the next one is different so we need to
160 * print what we collected so far.
161 */
162static void note_page(struct seq_file *m, struct pg_state *st,
163 pgprot_t new_prot, int level)
164{
165 pgprotval_t prot, cur;
166 static const char units[] = "KMGTPE";
167
168 /*
169 * If we have a "break" in the series, we need to flush the state that
170 * we have now. "break" is either changing perms, levels or
171 * address space marker.
172 */
173 prot = pgprot_val(new_prot) & PTE_FLAGS_MASK;
174 cur = pgprot_val(st->current_prot) & PTE_FLAGS_MASK;
175
176 if (!st->level) {
177 /* First entry */
178 st->current_prot = new_prot;
179 st->level = level;
180 st->marker = address_markers;
181 seq_printf(m, "---[ %s ]---\n", st->marker->name);
182 } else if (prot != cur || level != st->level ||
183 st->current_address >= st->marker[1].start_address) {
184 const char *unit = units;
185 unsigned long delta;
186 int width = sizeof(unsigned long) * 2;
187
188 /*
189 * Now print the actual finished series
190 */
191 seq_printf(m, "0x%0*lx-0x%0*lx ",
192 width, st->start_address,
193 width, st->current_address);
194
195 delta = (st->current_address - st->start_address) >> 10;
196 while (!(delta & 1023) && unit[1]) {
197 delta >>= 10;
198 unit++;
199 }
200 seq_printf(m, "%9lu%c ", delta, *unit);
201 printk_prot(m, st->current_prot, st->level);
202
203 /*
204 * We print markers for special areas of address space,
205 * such as the start of vmalloc space etc.
206 * This helps in the interpretation.
207 */
208 if (st->current_address >= st->marker[1].start_address) {
209 st->marker++;
210 seq_printf(m, "---[ %s ]---\n", st->marker->name);
211 }
212
213 st->start_address = st->current_address;
214 st->current_prot = new_prot;
215 st->level = level;
216 }
217}
218
219static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr,
220 unsigned long P)
221{
222 int i;
223 pte_t *start;
224
225 start = (pte_t *) pmd_page_vaddr(addr);
226 for (i = 0; i < PTRS_PER_PTE; i++) {
227 pgprot_t prot = pte_pgprot(*start);
228
229 st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);
230 note_page(m, st, prot, 4);
231 start++;
232 }
233}
234
235#if PTRS_PER_PMD > 1
236
237static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pud_t addr,
238 unsigned long P)
239{
240 int i;
241 pmd_t *start;
242
243 start = (pmd_t *) pud_page_vaddr(addr);
244 for (i = 0; i < PTRS_PER_PMD; i++) {
245 st->current_address = normalize_addr(P + i * PMD_LEVEL_MULT);
246 if (!pmd_none(*start)) {
247 pgprotval_t prot = pmd_val(*start) & PTE_FLAGS_MASK;
248
249 if (pmd_large(*start) || !pmd_present(*start))
250 note_page(m, st, __pgprot(prot), 3);
251 else
252 walk_pte_level(m, st, *start,
253 P + i * PMD_LEVEL_MULT);
254 } else
255 note_page(m, st, __pgprot(0), 3);
256 start++;
257 }
258}
259
260#else
261#define walk_pmd_level(m,s,a,p) walk_pte_level(m,s,__pmd(pud_val(a)),p)
262#define pud_large(a) pmd_large(__pmd(pud_val(a)))
263#define pud_none(a) pmd_none(__pmd(pud_val(a)))
264#endif
265
266#if PTRS_PER_PUD > 1
267
268static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr,
269 unsigned long P)
270{
271 int i;
272 pud_t *start;
273
274 start = (pud_t *) pgd_page_vaddr(addr);
275
276 for (i = 0; i < PTRS_PER_PUD; i++) {
277 st->current_address = normalize_addr(P + i * PUD_LEVEL_MULT);
278 if (!pud_none(*start)) {
279 pgprotval_t prot = pud_val(*start) & PTE_FLAGS_MASK;
280
281 if (pud_large(*start) || !pud_present(*start))
282 note_page(m, st, __pgprot(prot), 2);
283 else
284 walk_pmd_level(m, st, *start,
285 P + i * PUD_LEVEL_MULT);
286 } else
287 note_page(m, st, __pgprot(0), 2);
288
289 start++;
290 }
291}
292
293#else
294#define walk_pud_level(m,s,a,p) walk_pmd_level(m,s,__pud(pgd_val(a)),p)
295#define pgd_large(a) pud_large(__pud(pgd_val(a)))
296#define pgd_none(a) pud_none(__pud(pgd_val(a)))
297#endif
298
299static void walk_pgd_level(struct seq_file *m)
300{
301#ifdef CONFIG_X86_64
302 pgd_t *start = (pgd_t *) &init_level4_pgt;
303#else
304 pgd_t *start = swapper_pg_dir;
305#endif
306 int i;
307 struct pg_state st;
308
309 memset(&st, 0, sizeof(st));
310
311 for (i = 0; i < PTRS_PER_PGD; i++) {
312 st.current_address = normalize_addr(i * PGD_LEVEL_MULT);
313 if (!pgd_none(*start)) {
314 pgprotval_t prot = pgd_val(*start) & PTE_FLAGS_MASK;
315
316 if (pgd_large(*start) || !pgd_present(*start))
317 note_page(m, &st, __pgprot(prot), 1);
318 else
319 walk_pud_level(m, &st, *start,
320 i * PGD_LEVEL_MULT);
321 } else
322 note_page(m, &st, __pgprot(0), 1);
323
324 start++;
325 }
326
327 /* Flush out the last page */
328 st.current_address = normalize_addr(PTRS_PER_PGD*PGD_LEVEL_MULT);
329 note_page(m, &st, __pgprot(0), 0);
330}
331
332static int ptdump_show(struct seq_file *m, void *v)
333{
334 walk_pgd_level(m);
335 return 0;
336}
337
338static int ptdump_open(struct inode *inode, struct file *filp)
339{
340 return single_open(filp, ptdump_show, NULL);
341}
342
343static const struct file_operations ptdump_fops = {
344 .open = ptdump_open,
345 .read = seq_read,
346 .llseek = seq_lseek,
347 .release = single_release,
348};
349
350static int pt_dump_init(void)
351{
352 struct dentry *pe;
353
354#ifdef CONFIG_X86_32
355 /* Not a compile-time constant on x86-32 */
356 address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
357 address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
358# ifdef CONFIG_HIGHMEM
359 address_markers[PKMAP_BASE_NR].start_address = PKMAP_BASE;
360# endif
361 address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
362#endif
363
364 pe = debugfs_create_file("kernel_page_tables", 0600, NULL, NULL,
365 &ptdump_fops);
366 if (!pe)
367 return -ENOMEM;
368
369 return 0;
370}
371
372__initcall(pt_dump_init);
373MODULE_LICENSE("GPL");
374MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
375MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");
1/*
2 * Debug helper to dump the current kernel pagetables of the system
3 * so that we can see what the various memory ranges are set to.
4 *
5 * (C) Copyright 2008 Intel Corporation
6 *
7 * Author: Arjan van de Ven <arjan@linux.intel.com>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; version 2
12 * of the License.
13 */
14
15#include <linux/debugfs.h>
16#include <linux/mm.h>
17#include <linux/module.h>
18#include <linux/seq_file.h>
19
20#include <asm/pgtable.h>
21
22/*
23 * The dumper groups pagetable entries of the same type into one, and for
24 * that it needs to keep some state when walking, and flush this state
25 * when a "break" in the continuity is found.
26 */
27struct pg_state {
28 int level;
29 pgprot_t current_prot;
30 unsigned long start_address;
31 unsigned long current_address;
32 const struct addr_marker *marker;
33 bool to_dmesg;
34};
35
36struct addr_marker {
37 unsigned long start_address;
38 const char *name;
39};
40
41/* indices for address_markers; keep sync'd w/ address_markers below */
42enum address_markers_idx {
43 USER_SPACE_NR = 0,
44#ifdef CONFIG_X86_64
45 KERNEL_SPACE_NR,
46 LOW_KERNEL_NR,
47 VMALLOC_START_NR,
48 VMEMMAP_START_NR,
49 HIGH_KERNEL_NR,
50 MODULES_VADDR_NR,
51 MODULES_END_NR,
52#else
53 KERNEL_SPACE_NR,
54 VMALLOC_START_NR,
55 VMALLOC_END_NR,
56# ifdef CONFIG_HIGHMEM
57 PKMAP_BASE_NR,
58# endif
59 FIXADDR_START_NR,
60#endif
61};
62
63/* Address space markers hints */
64static struct addr_marker address_markers[] = {
65 { 0, "User Space" },
66#ifdef CONFIG_X86_64
67 { 0x8000000000000000UL, "Kernel Space" },
68 { PAGE_OFFSET, "Low Kernel Mapping" },
69 { VMALLOC_START, "vmalloc() Area" },
70 { VMEMMAP_START, "Vmemmap" },
71 { __START_KERNEL_map, "High Kernel Mapping" },
72 { MODULES_VADDR, "Modules" },
73 { MODULES_END, "End Modules" },
74#else
75 { PAGE_OFFSET, "Kernel Mapping" },
76 { 0/* VMALLOC_START */, "vmalloc() Area" },
77 { 0/*VMALLOC_END*/, "vmalloc() End" },
78# ifdef CONFIG_HIGHMEM
79 { 0/*PKMAP_BASE*/, "Persisent kmap() Area" },
80# endif
81 { 0/*FIXADDR_START*/, "Fixmap Area" },
82#endif
83 { -1, NULL } /* End of list */
84};
85
86/* Multipliers for offsets within the PTEs */
87#define PTE_LEVEL_MULT (PAGE_SIZE)
88#define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
89#define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
90#define PGD_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
91
92#define pt_dump_seq_printf(m, to_dmesg, fmt, args...) \
93({ \
94 if (to_dmesg) \
95 printk(KERN_INFO fmt, ##args); \
96 else \
97 if (m) \
98 seq_printf(m, fmt, ##args); \
99})
100
101#define pt_dump_cont_printf(m, to_dmesg, fmt, args...) \
102({ \
103 if (to_dmesg) \
104 printk(KERN_CONT fmt, ##args); \
105 else \
106 if (m) \
107 seq_printf(m, fmt, ##args); \
108})
109
110/*
111 * Print a readable form of a pgprot_t to the seq_file
112 */
113static void printk_prot(struct seq_file *m, pgprot_t prot, int level, bool dmsg)
114{
115 pgprotval_t pr = pgprot_val(prot);
116 static const char * const level_name[] =
117 { "cr3", "pgd", "pud", "pmd", "pte" };
118
119 if (!pgprot_val(prot)) {
120 /* Not present */
121 pt_dump_cont_printf(m, dmsg, " ");
122 } else {
123 if (pr & _PAGE_USER)
124 pt_dump_cont_printf(m, dmsg, "USR ");
125 else
126 pt_dump_cont_printf(m, dmsg, " ");
127 if (pr & _PAGE_RW)
128 pt_dump_cont_printf(m, dmsg, "RW ");
129 else
130 pt_dump_cont_printf(m, dmsg, "ro ");
131 if (pr & _PAGE_PWT)
132 pt_dump_cont_printf(m, dmsg, "PWT ");
133 else
134 pt_dump_cont_printf(m, dmsg, " ");
135 if (pr & _PAGE_PCD)
136 pt_dump_cont_printf(m, dmsg, "PCD ");
137 else
138 pt_dump_cont_printf(m, dmsg, " ");
139
140 /* Bit 9 has a different meaning on level 3 vs 4 */
141 if (level <= 3) {
142 if (pr & _PAGE_PSE)
143 pt_dump_cont_printf(m, dmsg, "PSE ");
144 else
145 pt_dump_cont_printf(m, dmsg, " ");
146 } else {
147 if (pr & _PAGE_PAT)
148 pt_dump_cont_printf(m, dmsg, "pat ");
149 else
150 pt_dump_cont_printf(m, dmsg, " ");
151 }
152 if (pr & _PAGE_GLOBAL)
153 pt_dump_cont_printf(m, dmsg, "GLB ");
154 else
155 pt_dump_cont_printf(m, dmsg, " ");
156 if (pr & _PAGE_NX)
157 pt_dump_cont_printf(m, dmsg, "NX ");
158 else
159 pt_dump_cont_printf(m, dmsg, "x ");
160 }
161 pt_dump_cont_printf(m, dmsg, "%s\n", level_name[level]);
162}
163
164/*
165 * On 64 bits, sign-extend the 48 bit address to 64 bit
166 */
167static unsigned long normalize_addr(unsigned long u)
168{
169#ifdef CONFIG_X86_64
170 return (signed long)(u << 16) >> 16;
171#else
172 return u;
173#endif
174}
175
176/*
177 * This function gets called on a break in a continuous series
178 * of PTE entries; the next one is different so we need to
179 * print what we collected so far.
180 */
181static void note_page(struct seq_file *m, struct pg_state *st,
182 pgprot_t new_prot, int level)
183{
184 pgprotval_t prot, cur;
185 static const char units[] = "KMGTPE";
186
187 /*
188 * If we have a "break" in the series, we need to flush the state that
189 * we have now. "break" is either changing perms, levels or
190 * address space marker.
191 */
192 prot = pgprot_val(new_prot) & PTE_FLAGS_MASK;
193 cur = pgprot_val(st->current_prot) & PTE_FLAGS_MASK;
194
195 if (!st->level) {
196 /* First entry */
197 st->current_prot = new_prot;
198 st->level = level;
199 st->marker = address_markers;
200 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
201 st->marker->name);
202 } else if (prot != cur || level != st->level ||
203 st->current_address >= st->marker[1].start_address) {
204 const char *unit = units;
205 unsigned long delta;
206 int width = sizeof(unsigned long) * 2;
207
208 /*
209 * Now print the actual finished series
210 */
211 pt_dump_seq_printf(m, st->to_dmesg, "0x%0*lx-0x%0*lx ",
212 width, st->start_address,
213 width, st->current_address);
214
215 delta = (st->current_address - st->start_address) >> 10;
216 while (!(delta & 1023) && unit[1]) {
217 delta >>= 10;
218 unit++;
219 }
220 pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ", delta, *unit);
221 printk_prot(m, st->current_prot, st->level, st->to_dmesg);
222
223 /*
224 * We print markers for special areas of address space,
225 * such as the start of vmalloc space etc.
226 * This helps in the interpretation.
227 */
228 if (st->current_address >= st->marker[1].start_address) {
229 st->marker++;
230 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
231 st->marker->name);
232 }
233
234 st->start_address = st->current_address;
235 st->current_prot = new_prot;
236 st->level = level;
237 }
238}
239
240static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr,
241 unsigned long P)
242{
243 int i;
244 pte_t *start;
245
246 start = (pte_t *) pmd_page_vaddr(addr);
247 for (i = 0; i < PTRS_PER_PTE; i++) {
248 pgprot_t prot = pte_pgprot(*start);
249
250 st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);
251 note_page(m, st, prot, 4);
252 start++;
253 }
254}
255
256#if PTRS_PER_PMD > 1
257
258static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pud_t addr,
259 unsigned long P)
260{
261 int i;
262 pmd_t *start;
263
264 start = (pmd_t *) pud_page_vaddr(addr);
265 for (i = 0; i < PTRS_PER_PMD; i++) {
266 st->current_address = normalize_addr(P + i * PMD_LEVEL_MULT);
267 if (!pmd_none(*start)) {
268 pgprotval_t prot = pmd_val(*start) & PTE_FLAGS_MASK;
269
270 if (pmd_large(*start) || !pmd_present(*start))
271 note_page(m, st, __pgprot(prot), 3);
272 else
273 walk_pte_level(m, st, *start,
274 P + i * PMD_LEVEL_MULT);
275 } else
276 note_page(m, st, __pgprot(0), 3);
277 start++;
278 }
279}
280
281#else
282#define walk_pmd_level(m,s,a,p) walk_pte_level(m,s,__pmd(pud_val(a)),p)
283#define pud_large(a) pmd_large(__pmd(pud_val(a)))
284#define pud_none(a) pmd_none(__pmd(pud_val(a)))
285#endif
286
287#if PTRS_PER_PUD > 1
288
289static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr,
290 unsigned long P)
291{
292 int i;
293 pud_t *start;
294
295 start = (pud_t *) pgd_page_vaddr(addr);
296
297 for (i = 0; i < PTRS_PER_PUD; i++) {
298 st->current_address = normalize_addr(P + i * PUD_LEVEL_MULT);
299 if (!pud_none(*start)) {
300 pgprotval_t prot = pud_val(*start) & PTE_FLAGS_MASK;
301
302 if (pud_large(*start) || !pud_present(*start))
303 note_page(m, st, __pgprot(prot), 2);
304 else
305 walk_pmd_level(m, st, *start,
306 P + i * PUD_LEVEL_MULT);
307 } else
308 note_page(m, st, __pgprot(0), 2);
309
310 start++;
311 }
312}
313
314#else
315#define walk_pud_level(m,s,a,p) walk_pmd_level(m,s,__pud(pgd_val(a)),p)
316#define pgd_large(a) pud_large(__pud(pgd_val(a)))
317#define pgd_none(a) pud_none(__pud(pgd_val(a)))
318#endif
319
320void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
321{
322#ifdef CONFIG_X86_64
323 pgd_t *start = (pgd_t *) &init_level4_pgt;
324#else
325 pgd_t *start = swapper_pg_dir;
326#endif
327 int i;
328 struct pg_state st = {};
329
330 if (pgd) {
331 start = pgd;
332 st.to_dmesg = true;
333 }
334
335 for (i = 0; i < PTRS_PER_PGD; i++) {
336 st.current_address = normalize_addr(i * PGD_LEVEL_MULT);
337 if (!pgd_none(*start)) {
338 pgprotval_t prot = pgd_val(*start) & PTE_FLAGS_MASK;
339
340 if (pgd_large(*start) || !pgd_present(*start))
341 note_page(m, &st, __pgprot(prot), 1);
342 else
343 walk_pud_level(m, &st, *start,
344 i * PGD_LEVEL_MULT);
345 } else
346 note_page(m, &st, __pgprot(0), 1);
347
348 start++;
349 }
350
351 /* Flush out the last page */
352 st.current_address = normalize_addr(PTRS_PER_PGD*PGD_LEVEL_MULT);
353 note_page(m, &st, __pgprot(0), 0);
354}
355
356static int ptdump_show(struct seq_file *m, void *v)
357{
358 ptdump_walk_pgd_level(m, NULL);
359 return 0;
360}
361
362static int ptdump_open(struct inode *inode, struct file *filp)
363{
364 return single_open(filp, ptdump_show, NULL);
365}
366
367static const struct file_operations ptdump_fops = {
368 .open = ptdump_open,
369 .read = seq_read,
370 .llseek = seq_lseek,
371 .release = single_release,
372};
373
374static int pt_dump_init(void)
375{
376 struct dentry *pe;
377
378#ifdef CONFIG_X86_32
379 /* Not a compile-time constant on x86-32 */
380 address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
381 address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
382# ifdef CONFIG_HIGHMEM
383 address_markers[PKMAP_BASE_NR].start_address = PKMAP_BASE;
384# endif
385 address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
386#endif
387
388 pe = debugfs_create_file("kernel_page_tables", 0600, NULL, NULL,
389 &ptdump_fops);
390 if (!pe)
391 return -ENOMEM;
392
393 return 0;
394}
395
396__initcall(pt_dump_init);
397MODULE_LICENSE("GPL");
398MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
399MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");