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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
24
25
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
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
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() Area" },
76 { 0, "vmalloc() End" },
77# ifdef CONFIG_HIGHMEM
78 { 0, "Persisent kmap() Area" },
79# endif
80 { 0, "Fixmap Area" },
81#endif
82 { -1, NULL }
83};
84
85
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
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
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
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
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
159
160
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
170
171
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
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
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
205
206
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
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
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");
376