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1// SPDX-License-Identifier: GPL-2.0-only
2/*
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 * (C) Copyright 2008 Intel Corporation
7 *
8 * Author: Arjan van de Ven <arjan@linux.intel.com>
9 */
10
11#include <linux/debugfs.h>
12#include <linux/kasan.h>
13#include <linux/mm.h>
14#include <linux/init.h>
15#include <linux/sched.h>
16#include <linux/seq_file.h>
17#include <linux/highmem.h>
18#include <linux/pci.h>
19#include <linux/ptdump.h>
20
21#include <asm/e820/types.h>
22
23/*
24 * The dumper groups pagetable entries of the same type into one, and for
25 * that it needs to keep some state when walking, and flush this state
26 * when a "break" in the continuity is found.
27 */
28struct pg_state {
29 struct ptdump_state ptdump;
30 int level;
31 pgprotval_t current_prot;
32 pgprotval_t effective_prot;
33 pgprotval_t prot_levels[5];
34 unsigned long start_address;
35 const struct addr_marker *marker;
36 unsigned long lines;
37 bool to_dmesg;
38 bool check_wx;
39 unsigned long wx_pages;
40 struct seq_file *seq;
41};
42
43struct addr_marker {
44 unsigned long start_address;
45 const char *name;
46 unsigned long max_lines;
47};
48
49/* Address space markers hints */
50
51#ifdef CONFIG_X86_64
52
53enum address_markers_idx {
54 USER_SPACE_NR = 0,
55 KERNEL_SPACE_NR,
56#ifdef CONFIG_MODIFY_LDT_SYSCALL
57 LDT_NR,
58#endif
59 LOW_KERNEL_NR,
60 VMALLOC_START_NR,
61 VMEMMAP_START_NR,
62#ifdef CONFIG_KASAN
63 KASAN_SHADOW_START_NR,
64 KASAN_SHADOW_END_NR,
65#endif
66 CPU_ENTRY_AREA_NR,
67#ifdef CONFIG_X86_ESPFIX64
68 ESPFIX_START_NR,
69#endif
70#ifdef CONFIG_EFI
71 EFI_END_NR,
72#endif
73 HIGH_KERNEL_NR,
74 MODULES_VADDR_NR,
75 MODULES_END_NR,
76 FIXADDR_START_NR,
77 END_OF_SPACE_NR,
78};
79
80static struct addr_marker address_markers[] = {
81 [USER_SPACE_NR] = { 0, "User Space" },
82 [KERNEL_SPACE_NR] = { (1UL << 63), "Kernel Space" },
83 [LOW_KERNEL_NR] = { 0UL, "Low Kernel Mapping" },
84 [VMALLOC_START_NR] = { 0UL, "vmalloc() Area" },
85 [VMEMMAP_START_NR] = { 0UL, "Vmemmap" },
86#ifdef CONFIG_KASAN
87 /*
88 * These fields get initialized with the (dynamic)
89 * KASAN_SHADOW_{START,END} values in pt_dump_init().
90 */
91 [KASAN_SHADOW_START_NR] = { 0UL, "KASAN shadow" },
92 [KASAN_SHADOW_END_NR] = { 0UL, "KASAN shadow end" },
93#endif
94#ifdef CONFIG_MODIFY_LDT_SYSCALL
95 [LDT_NR] = { 0UL, "LDT remap" },
96#endif
97 [CPU_ENTRY_AREA_NR] = { CPU_ENTRY_AREA_BASE,"CPU entry Area" },
98#ifdef CONFIG_X86_ESPFIX64
99 [ESPFIX_START_NR] = { ESPFIX_BASE_ADDR, "ESPfix Area", 16 },
100#endif
101#ifdef CONFIG_EFI
102 [EFI_END_NR] = { EFI_VA_END, "EFI Runtime Services" },
103#endif
104 [HIGH_KERNEL_NR] = { __START_KERNEL_map, "High Kernel Mapping" },
105 [MODULES_VADDR_NR] = { MODULES_VADDR, "Modules" },
106 [MODULES_END_NR] = { MODULES_END, "End Modules" },
107 [FIXADDR_START_NR] = { FIXADDR_START, "Fixmap Area" },
108 [END_OF_SPACE_NR] = { -1, NULL }
109};
110
111#define INIT_PGD ((pgd_t *) &init_top_pgt)
112
113#else /* CONFIG_X86_64 */
114
115enum address_markers_idx {
116 USER_SPACE_NR = 0,
117 KERNEL_SPACE_NR,
118 VMALLOC_START_NR,
119 VMALLOC_END_NR,
120#ifdef CONFIG_HIGHMEM
121 PKMAP_BASE_NR,
122#endif
123#ifdef CONFIG_MODIFY_LDT_SYSCALL
124 LDT_NR,
125#endif
126 CPU_ENTRY_AREA_NR,
127 FIXADDR_START_NR,
128 END_OF_SPACE_NR,
129};
130
131static struct addr_marker address_markers[] = {
132 [USER_SPACE_NR] = { 0, "User Space" },
133 [KERNEL_SPACE_NR] = { PAGE_OFFSET, "Kernel Mapping" },
134 [VMALLOC_START_NR] = { 0UL, "vmalloc() Area" },
135 [VMALLOC_END_NR] = { 0UL, "vmalloc() End" },
136#ifdef CONFIG_HIGHMEM
137 [PKMAP_BASE_NR] = { 0UL, "Persistent kmap() Area" },
138#endif
139#ifdef CONFIG_MODIFY_LDT_SYSCALL
140 [LDT_NR] = { 0UL, "LDT remap" },
141#endif
142 [CPU_ENTRY_AREA_NR] = { 0UL, "CPU entry area" },
143 [FIXADDR_START_NR] = { 0UL, "Fixmap area" },
144 [END_OF_SPACE_NR] = { -1, NULL }
145};
146
147#define INIT_PGD (swapper_pg_dir)
148
149#endif /* !CONFIG_X86_64 */
150
151/* Multipliers for offsets within the PTEs */
152#define PTE_LEVEL_MULT (PAGE_SIZE)
153#define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
154#define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
155#define P4D_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
156#define PGD_LEVEL_MULT (PTRS_PER_P4D * P4D_LEVEL_MULT)
157
158#define pt_dump_seq_printf(m, to_dmesg, fmt, args...) \
159({ \
160 if (to_dmesg) \
161 printk(KERN_INFO fmt, ##args); \
162 else \
163 if (m) \
164 seq_printf(m, fmt, ##args); \
165})
166
167#define pt_dump_cont_printf(m, to_dmesg, fmt, args...) \
168({ \
169 if (to_dmesg) \
170 printk(KERN_CONT fmt, ##args); \
171 else \
172 if (m) \
173 seq_printf(m, fmt, ##args); \
174})
175
176/*
177 * Print a readable form of a pgprot_t to the seq_file
178 */
179static void printk_prot(struct seq_file *m, pgprotval_t pr, int level, bool dmsg)
180{
181 static const char * const level_name[] =
182 { "pgd", "p4d", "pud", "pmd", "pte" };
183
184 if (!(pr & _PAGE_PRESENT)) {
185 /* Not present */
186 pt_dump_cont_printf(m, dmsg, " ");
187 } else {
188 if (pr & _PAGE_USER)
189 pt_dump_cont_printf(m, dmsg, "USR ");
190 else
191 pt_dump_cont_printf(m, dmsg, " ");
192 if (pr & _PAGE_RW)
193 pt_dump_cont_printf(m, dmsg, "RW ");
194 else
195 pt_dump_cont_printf(m, dmsg, "ro ");
196 if (pr & _PAGE_PWT)
197 pt_dump_cont_printf(m, dmsg, "PWT ");
198 else
199 pt_dump_cont_printf(m, dmsg, " ");
200 if (pr & _PAGE_PCD)
201 pt_dump_cont_printf(m, dmsg, "PCD ");
202 else
203 pt_dump_cont_printf(m, dmsg, " ");
204
205 /* Bit 7 has a different meaning on level 3 vs 4 */
206 if (level <= 3 && pr & _PAGE_PSE)
207 pt_dump_cont_printf(m, dmsg, "PSE ");
208 else
209 pt_dump_cont_printf(m, dmsg, " ");
210 if ((level == 4 && pr & _PAGE_PAT) ||
211 ((level == 3 || level == 2) && pr & _PAGE_PAT_LARGE))
212 pt_dump_cont_printf(m, dmsg, "PAT ");
213 else
214 pt_dump_cont_printf(m, dmsg, " ");
215 if (pr & _PAGE_GLOBAL)
216 pt_dump_cont_printf(m, dmsg, "GLB ");
217 else
218 pt_dump_cont_printf(m, dmsg, " ");
219 if (pr & _PAGE_NX)
220 pt_dump_cont_printf(m, dmsg, "NX ");
221 else
222 pt_dump_cont_printf(m, dmsg, "x ");
223 }
224 pt_dump_cont_printf(m, dmsg, "%s\n", level_name[level]);
225}
226
227static void note_wx(struct pg_state *st, unsigned long addr)
228{
229 unsigned long npages;
230
231 npages = (addr - st->start_address) / PAGE_SIZE;
232
233#ifdef CONFIG_PCI_BIOS
234 /*
235 * If PCI BIOS is enabled, the PCI BIOS area is forced to WX.
236 * Inform about it, but avoid the warning.
237 */
238 if (pcibios_enabled && st->start_address >= PAGE_OFFSET + BIOS_BEGIN &&
239 addr <= PAGE_OFFSET + BIOS_END) {
240 pr_warn_once("x86/mm: PCI BIOS W+X mapping %lu pages\n", npages);
241 return;
242 }
243#endif
244 /* Account the WX pages */
245 st->wx_pages += npages;
246 WARN_ONCE(__supported_pte_mask & _PAGE_NX,
247 "x86/mm: Found insecure W+X mapping at address %pS\n",
248 (void *)st->start_address);
249}
250
251static void effective_prot(struct ptdump_state *pt_st, int level, u64 val)
252{
253 struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
254 pgprotval_t prot = val & PTE_FLAGS_MASK;
255 pgprotval_t effective;
256
257 if (level > 0) {
258 pgprotval_t higher_prot = st->prot_levels[level - 1];
259
260 effective = (higher_prot & prot & (_PAGE_USER | _PAGE_RW)) |
261 ((higher_prot | prot) & _PAGE_NX);
262 } else {
263 effective = prot;
264 }
265
266 st->prot_levels[level] = effective;
267}
268
269/*
270 * This function gets called on a break in a continuous series
271 * of PTE entries; the next one is different so we need to
272 * print what we collected so far.
273 */
274static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
275 u64 val)
276{
277 struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
278 pgprotval_t new_prot, new_eff;
279 pgprotval_t cur, eff;
280 static const char units[] = "BKMGTPE";
281 struct seq_file *m = st->seq;
282
283 new_prot = val & PTE_FLAGS_MASK;
284 if (!val)
285 new_eff = 0;
286 else
287 new_eff = st->prot_levels[level];
288
289 /*
290 * If we have a "break" in the series, we need to flush the state that
291 * we have now. "break" is either changing perms, levels or
292 * address space marker.
293 */
294 cur = st->current_prot;
295 eff = st->effective_prot;
296
297 if (st->level == -1) {
298 /* First entry */
299 st->current_prot = new_prot;
300 st->effective_prot = new_eff;
301 st->level = level;
302 st->marker = address_markers;
303 st->lines = 0;
304 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
305 st->marker->name);
306 } else if (new_prot != cur || new_eff != eff || level != st->level ||
307 addr >= st->marker[1].start_address) {
308 const char *unit = units;
309 unsigned long delta;
310 int width = sizeof(unsigned long) * 2;
311
312 if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX))
313 note_wx(st, addr);
314
315 /*
316 * Now print the actual finished series
317 */
318 if (!st->marker->max_lines ||
319 st->lines < st->marker->max_lines) {
320 pt_dump_seq_printf(m, st->to_dmesg,
321 "0x%0*lx-0x%0*lx ",
322 width, st->start_address,
323 width, addr);
324
325 delta = addr - st->start_address;
326 while (!(delta & 1023) && unit[1]) {
327 delta >>= 10;
328 unit++;
329 }
330 pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ",
331 delta, *unit);
332 printk_prot(m, st->current_prot, st->level,
333 st->to_dmesg);
334 }
335 st->lines++;
336
337 /*
338 * We print markers for special areas of address space,
339 * such as the start of vmalloc space etc.
340 * This helps in the interpretation.
341 */
342 if (addr >= st->marker[1].start_address) {
343 if (st->marker->max_lines &&
344 st->lines > st->marker->max_lines) {
345 unsigned long nskip =
346 st->lines - st->marker->max_lines;
347 pt_dump_seq_printf(m, st->to_dmesg,
348 "... %lu entr%s skipped ... \n",
349 nskip,
350 nskip == 1 ? "y" : "ies");
351 }
352 st->marker++;
353 st->lines = 0;
354 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
355 st->marker->name);
356 }
357
358 st->start_address = addr;
359 st->current_prot = new_prot;
360 st->effective_prot = new_eff;
361 st->level = level;
362 }
363}
364
365static void ptdump_walk_pgd_level_core(struct seq_file *m,
366 struct mm_struct *mm, pgd_t *pgd,
367 bool checkwx, bool dmesg)
368{
369 const struct ptdump_range ptdump_ranges[] = {
370#ifdef CONFIG_X86_64
371 {0, PTRS_PER_PGD * PGD_LEVEL_MULT / 2},
372 {GUARD_HOLE_END_ADDR, ~0UL},
373#else
374 {0, ~0UL},
375#endif
376 {0, 0}
377};
378
379 struct pg_state st = {
380 .ptdump = {
381 .note_page = note_page,
382 .effective_prot = effective_prot,
383 .range = ptdump_ranges
384 },
385 .level = -1,
386 .to_dmesg = dmesg,
387 .check_wx = checkwx,
388 .seq = m
389 };
390
391 ptdump_walk_pgd(&st.ptdump, mm, pgd);
392
393 if (!checkwx)
394 return;
395 if (st.wx_pages)
396 pr_info("x86/mm: Checked W+X mappings: FAILED, %lu W+X pages found.\n",
397 st.wx_pages);
398 else
399 pr_info("x86/mm: Checked W+X mappings: passed, no W+X pages found.\n");
400}
401
402void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm)
403{
404 ptdump_walk_pgd_level_core(m, mm, mm->pgd, false, true);
405}
406
407void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm,
408 bool user)
409{
410 pgd_t *pgd = mm->pgd;
411#ifdef CONFIG_PAGE_TABLE_ISOLATION
412 if (user && boot_cpu_has(X86_FEATURE_PTI))
413 pgd = kernel_to_user_pgdp(pgd);
414#endif
415 ptdump_walk_pgd_level_core(m, mm, pgd, false, false);
416}
417EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs);
418
419void ptdump_walk_user_pgd_level_checkwx(void)
420{
421#ifdef CONFIG_PAGE_TABLE_ISOLATION
422 pgd_t *pgd = INIT_PGD;
423
424 if (!(__supported_pte_mask & _PAGE_NX) ||
425 !boot_cpu_has(X86_FEATURE_PTI))
426 return;
427
428 pr_info("x86/mm: Checking user space page tables\n");
429 pgd = kernel_to_user_pgdp(pgd);
430 ptdump_walk_pgd_level_core(NULL, &init_mm, pgd, true, false);
431#endif
432}
433
434void ptdump_walk_pgd_level_checkwx(void)
435{
436 ptdump_walk_pgd_level_core(NULL, &init_mm, INIT_PGD, true, false);
437}
438
439static int __init pt_dump_init(void)
440{
441 /*
442 * Various markers are not compile-time constants, so assign them
443 * here.
444 */
445#ifdef CONFIG_X86_64
446 address_markers[LOW_KERNEL_NR].start_address = PAGE_OFFSET;
447 address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
448 address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START;
449#ifdef CONFIG_MODIFY_LDT_SYSCALL
450 address_markers[LDT_NR].start_address = LDT_BASE_ADDR;
451#endif
452#ifdef CONFIG_KASAN
453 address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START;
454 address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END;
455#endif
456#endif
457#ifdef CONFIG_X86_32
458 address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
459 address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
460# ifdef CONFIG_HIGHMEM
461 address_markers[PKMAP_BASE_NR].start_address = PKMAP_BASE;
462# endif
463 address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
464 address_markers[CPU_ENTRY_AREA_NR].start_address = CPU_ENTRY_AREA_BASE;
465# ifdef CONFIG_MODIFY_LDT_SYSCALL
466 address_markers[LDT_NR].start_address = LDT_BASE_ADDR;
467# endif
468#endif
469 return 0;
470}
471__initcall(pt_dump_init);
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");