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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 unsigned long lines;
34 bool to_dmesg;
35 bool check_wx;
36 unsigned long wx_pages;
37};
38
39struct addr_marker {
40 unsigned long start_address;
41 const char *name;
42 unsigned long max_lines;
43};
44
45/* indices for address_markers; keep sync'd w/ address_markers below */
46enum address_markers_idx {
47 USER_SPACE_NR = 0,
48#ifdef CONFIG_X86_64
49 KERNEL_SPACE_NR,
50 LOW_KERNEL_NR,
51 VMALLOC_START_NR,
52 VMEMMAP_START_NR,
53# ifdef CONFIG_X86_ESPFIX64
54 ESPFIX_START_NR,
55# endif
56 HIGH_KERNEL_NR,
57 MODULES_VADDR_NR,
58 MODULES_END_NR,
59#else
60 KERNEL_SPACE_NR,
61 VMALLOC_START_NR,
62 VMALLOC_END_NR,
63# ifdef CONFIG_HIGHMEM
64 PKMAP_BASE_NR,
65# endif
66 FIXADDR_START_NR,
67#endif
68};
69
70/* Address space markers hints */
71static struct addr_marker address_markers[] = {
72 { 0, "User Space" },
73#ifdef CONFIG_X86_64
74 { 0x8000000000000000UL, "Kernel Space" },
75 { PAGE_OFFSET, "Low Kernel Mapping" },
76 { VMALLOC_START, "vmalloc() Area" },
77 { VMEMMAP_START, "Vmemmap" },
78# ifdef CONFIG_X86_ESPFIX64
79 { ESPFIX_BASE_ADDR, "ESPfix Area", 16 },
80# endif
81# ifdef CONFIG_EFI
82 { EFI_VA_END, "EFI Runtime Services" },
83# endif
84 { __START_KERNEL_map, "High Kernel Mapping" },
85 { MODULES_VADDR, "Modules" },
86 { MODULES_END, "End Modules" },
87#else
88 { PAGE_OFFSET, "Kernel Mapping" },
89 { 0/* VMALLOC_START */, "vmalloc() Area" },
90 { 0/*VMALLOC_END*/, "vmalloc() End" },
91# ifdef CONFIG_HIGHMEM
92 { 0/*PKMAP_BASE*/, "Persistent kmap() Area" },
93# endif
94 { 0/*FIXADDR_START*/, "Fixmap Area" },
95#endif
96 { -1, NULL } /* End of list */
97};
98
99/* Multipliers for offsets within the PTEs */
100#define PTE_LEVEL_MULT (PAGE_SIZE)
101#define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
102#define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
103#define PGD_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
104
105#define pt_dump_seq_printf(m, to_dmesg, fmt, args...) \
106({ \
107 if (to_dmesg) \
108 printk(KERN_INFO fmt, ##args); \
109 else \
110 if (m) \
111 seq_printf(m, fmt, ##args); \
112})
113
114#define pt_dump_cont_printf(m, to_dmesg, fmt, args...) \
115({ \
116 if (to_dmesg) \
117 printk(KERN_CONT fmt, ##args); \
118 else \
119 if (m) \
120 seq_printf(m, fmt, ##args); \
121})
122
123/*
124 * Print a readable form of a pgprot_t to the seq_file
125 */
126static void printk_prot(struct seq_file *m, pgprot_t prot, int level, bool dmsg)
127{
128 pgprotval_t pr = pgprot_val(prot);
129 static const char * const level_name[] =
130 { "cr3", "pgd", "pud", "pmd", "pte" };
131
132 if (!pgprot_val(prot)) {
133 /* Not present */
134 pt_dump_cont_printf(m, dmsg, " ");
135 } else {
136 if (pr & _PAGE_USER)
137 pt_dump_cont_printf(m, dmsg, "USR ");
138 else
139 pt_dump_cont_printf(m, dmsg, " ");
140 if (pr & _PAGE_RW)
141 pt_dump_cont_printf(m, dmsg, "RW ");
142 else
143 pt_dump_cont_printf(m, dmsg, "ro ");
144 if (pr & _PAGE_PWT)
145 pt_dump_cont_printf(m, dmsg, "PWT ");
146 else
147 pt_dump_cont_printf(m, dmsg, " ");
148 if (pr & _PAGE_PCD)
149 pt_dump_cont_printf(m, dmsg, "PCD ");
150 else
151 pt_dump_cont_printf(m, dmsg, " ");
152
153 /* Bit 7 has a different meaning on level 3 vs 4 */
154 if (level <= 3 && pr & _PAGE_PSE)
155 pt_dump_cont_printf(m, dmsg, "PSE ");
156 else
157 pt_dump_cont_printf(m, dmsg, " ");
158 if ((level == 4 && pr & _PAGE_PAT) ||
159 ((level == 3 || level == 2) && pr & _PAGE_PAT_LARGE))
160 pt_dump_cont_printf(m, dmsg, "PAT ");
161 else
162 pt_dump_cont_printf(m, dmsg, " ");
163 if (pr & _PAGE_GLOBAL)
164 pt_dump_cont_printf(m, dmsg, "GLB ");
165 else
166 pt_dump_cont_printf(m, dmsg, " ");
167 if (pr & _PAGE_NX)
168 pt_dump_cont_printf(m, dmsg, "NX ");
169 else
170 pt_dump_cont_printf(m, dmsg, "x ");
171 }
172 pt_dump_cont_printf(m, dmsg, "%s\n", level_name[level]);
173}
174
175/*
176 * On 64 bits, sign-extend the 48 bit address to 64 bit
177 */
178static unsigned long normalize_addr(unsigned long u)
179{
180#ifdef CONFIG_X86_64
181 return (signed long)(u << 16) >> 16;
182#else
183 return u;
184#endif
185}
186
187/*
188 * This function gets called on a break in a continuous series
189 * of PTE entries; the next one is different so we need to
190 * print what we collected so far.
191 */
192static void note_page(struct seq_file *m, struct pg_state *st,
193 pgprot_t new_prot, int level)
194{
195 pgprotval_t prot, cur;
196 static const char units[] = "BKMGTPE";
197
198 /*
199 * If we have a "break" in the series, we need to flush the state that
200 * we have now. "break" is either changing perms, levels or
201 * address space marker.
202 */
203 prot = pgprot_val(new_prot);
204 cur = pgprot_val(st->current_prot);
205
206 if (!st->level) {
207 /* First entry */
208 st->current_prot = new_prot;
209 st->level = level;
210 st->marker = address_markers;
211 st->lines = 0;
212 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
213 st->marker->name);
214 } else if (prot != cur || level != st->level ||
215 st->current_address >= st->marker[1].start_address) {
216 const char *unit = units;
217 unsigned long delta;
218 int width = sizeof(unsigned long) * 2;
219 pgprotval_t pr = pgprot_val(st->current_prot);
220
221 if (st->check_wx && (pr & _PAGE_RW) && !(pr & _PAGE_NX)) {
222 WARN_ONCE(1,
223 "x86/mm: Found insecure W+X mapping at address %p/%pS\n",
224 (void *)st->start_address,
225 (void *)st->start_address);
226 st->wx_pages += (st->current_address -
227 st->start_address) / PAGE_SIZE;
228 }
229
230 /*
231 * Now print the actual finished series
232 */
233 if (!st->marker->max_lines ||
234 st->lines < st->marker->max_lines) {
235 pt_dump_seq_printf(m, st->to_dmesg,
236 "0x%0*lx-0x%0*lx ",
237 width, st->start_address,
238 width, st->current_address);
239
240 delta = st->current_address - st->start_address;
241 while (!(delta & 1023) && unit[1]) {
242 delta >>= 10;
243 unit++;
244 }
245 pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ",
246 delta, *unit);
247 printk_prot(m, st->current_prot, st->level,
248 st->to_dmesg);
249 }
250 st->lines++;
251
252 /*
253 * We print markers for special areas of address space,
254 * such as the start of vmalloc space etc.
255 * This helps in the interpretation.
256 */
257 if (st->current_address >= st->marker[1].start_address) {
258 if (st->marker->max_lines &&
259 st->lines > st->marker->max_lines) {
260 unsigned long nskip =
261 st->lines - st->marker->max_lines;
262 pt_dump_seq_printf(m, st->to_dmesg,
263 "... %lu entr%s skipped ... \n",
264 nskip,
265 nskip == 1 ? "y" : "ies");
266 }
267 st->marker++;
268 st->lines = 0;
269 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
270 st->marker->name);
271 }
272
273 st->start_address = st->current_address;
274 st->current_prot = new_prot;
275 st->level = level;
276 }
277}
278
279static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr,
280 unsigned long P)
281{
282 int i;
283 pte_t *start;
284 pgprotval_t prot;
285
286 start = (pte_t *) pmd_page_vaddr(addr);
287 for (i = 0; i < PTRS_PER_PTE; i++) {
288 prot = pte_flags(*start);
289 st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);
290 note_page(m, st, __pgprot(prot), 4);
291 start++;
292 }
293}
294
295#if PTRS_PER_PMD > 1
296
297static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pud_t addr,
298 unsigned long P)
299{
300 int i;
301 pmd_t *start;
302 pgprotval_t prot;
303
304 start = (pmd_t *) pud_page_vaddr(addr);
305 for (i = 0; i < PTRS_PER_PMD; i++) {
306 st->current_address = normalize_addr(P + i * PMD_LEVEL_MULT);
307 if (!pmd_none(*start)) {
308 if (pmd_large(*start) || !pmd_present(*start)) {
309 prot = pmd_flags(*start);
310 note_page(m, st, __pgprot(prot), 3);
311 } else {
312 walk_pte_level(m, st, *start,
313 P + i * PMD_LEVEL_MULT);
314 }
315 } else
316 note_page(m, st, __pgprot(0), 3);
317 start++;
318 }
319}
320
321#else
322#define walk_pmd_level(m,s,a,p) walk_pte_level(m,s,__pmd(pud_val(a)),p)
323#define pud_large(a) pmd_large(__pmd(pud_val(a)))
324#define pud_none(a) pmd_none(__pmd(pud_val(a)))
325#endif
326
327#if PTRS_PER_PUD > 1
328
329static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr,
330 unsigned long P)
331{
332 int i;
333 pud_t *start;
334 pgprotval_t prot;
335
336 start = (pud_t *) pgd_page_vaddr(addr);
337
338 for (i = 0; i < PTRS_PER_PUD; i++) {
339 st->current_address = normalize_addr(P + i * PUD_LEVEL_MULT);
340 if (!pud_none(*start)) {
341 if (pud_large(*start) || !pud_present(*start)) {
342 prot = pud_flags(*start);
343 note_page(m, st, __pgprot(prot), 2);
344 } else {
345 walk_pmd_level(m, st, *start,
346 P + i * PUD_LEVEL_MULT);
347 }
348 } else
349 note_page(m, st, __pgprot(0), 2);
350
351 start++;
352 }
353}
354
355#else
356#define walk_pud_level(m,s,a,p) walk_pmd_level(m,s,__pud(pgd_val(a)),p)
357#define pgd_large(a) pud_large(__pud(pgd_val(a)))
358#define pgd_none(a) pud_none(__pud(pgd_val(a)))
359#endif
360
361static inline bool is_hypervisor_range(int idx)
362{
363#ifdef CONFIG_X86_64
364 /*
365 * ffff800000000000 - ffff87ffffffffff is reserved for
366 * the hypervisor.
367 */
368 return (idx >= pgd_index(__PAGE_OFFSET) - 16) &&
369 (idx < pgd_index(__PAGE_OFFSET));
370#else
371 return false;
372#endif
373}
374
375static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
376 bool checkwx)
377{
378#ifdef CONFIG_X86_64
379 pgd_t *start = (pgd_t *) &init_level4_pgt;
380#else
381 pgd_t *start = swapper_pg_dir;
382#endif
383 pgprotval_t prot;
384 int i;
385 struct pg_state st = {};
386
387 if (pgd) {
388 start = pgd;
389 st.to_dmesg = true;
390 }
391
392 st.check_wx = checkwx;
393 if (checkwx)
394 st.wx_pages = 0;
395
396 for (i = 0; i < PTRS_PER_PGD; i++) {
397 st.current_address = normalize_addr(i * PGD_LEVEL_MULT);
398 if (!pgd_none(*start) && !is_hypervisor_range(i)) {
399 if (pgd_large(*start) || !pgd_present(*start)) {
400 prot = pgd_flags(*start);
401 note_page(m, &st, __pgprot(prot), 1);
402 } else {
403 walk_pud_level(m, &st, *start,
404 i * PGD_LEVEL_MULT);
405 }
406 } else
407 note_page(m, &st, __pgprot(0), 1);
408
409 start++;
410 }
411
412 /* Flush out the last page */
413 st.current_address = normalize_addr(PTRS_PER_PGD*PGD_LEVEL_MULT);
414 note_page(m, &st, __pgprot(0), 0);
415 if (!checkwx)
416 return;
417 if (st.wx_pages)
418 pr_info("x86/mm: Checked W+X mappings: FAILED, %lu W+X pages found.\n",
419 st.wx_pages);
420 else
421 pr_info("x86/mm: Checked W+X mappings: passed, no W+X pages found.\n");
422}
423
424void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
425{
426 ptdump_walk_pgd_level_core(m, pgd, false);
427}
428EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level);
429
430void ptdump_walk_pgd_level_checkwx(void)
431{
432 ptdump_walk_pgd_level_core(NULL, NULL, true);
433}
434
435static int __init pt_dump_init(void)
436{
437#ifdef CONFIG_X86_32
438 /* Not a compile-time constant on x86-32 */
439 address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
440 address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
441# ifdef CONFIG_HIGHMEM
442 address_markers[PKMAP_BASE_NR].start_address = PKMAP_BASE;
443# endif
444 address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
445#endif
446
447 return 0;
448}
449
450__initcall(pt_dump_init);
451MODULE_LICENSE("GPL");
452MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
453MODULE_DESCRIPTION("Kernel debugging helper that dumps pagetables");
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);