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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/kasan.h>
17#include <linux/mm.h>
18#include <linux/init.h>
19#include <linux/sched.h>
20#include <linux/seq_file.h>
21#include <linux/highmem.h>
22
23#include <asm/pgtable.h>
24
25/*
26 * The dumper groups pagetable entries of the same type into one, and for
27 * that it needs to keep some state when walking, and flush this state
28 * when a "break" in the continuity is found.
29 */
30struct pg_state {
31 int level;
32 pgprot_t current_prot;
33 pgprotval_t effective_prot;
34 unsigned long start_address;
35 unsigned long current_address;
36 const struct addr_marker *marker;
37 unsigned long lines;
38 bool to_dmesg;
39 bool check_wx;
40 unsigned long wx_pages;
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 LOW_KERNEL_NR,
57#if defined(CONFIG_MODIFY_LDT_SYSCALL) && defined(CONFIG_X86_5LEVEL)
58 LDT_NR,
59#endif
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#if defined(CONFIG_MODIFY_LDT_SYSCALL) && !defined(CONFIG_X86_5LEVEL)
68 LDT_NR,
69#endif
70#ifdef CONFIG_X86_ESPFIX64
71 ESPFIX_START_NR,
72#endif
73#ifdef CONFIG_EFI
74 EFI_END_NR,
75#endif
76 HIGH_KERNEL_NR,
77 MODULES_VADDR_NR,
78 MODULES_END_NR,
79 FIXADDR_START_NR,
80 END_OF_SPACE_NR,
81};
82
83static struct addr_marker address_markers[] = {
84 [USER_SPACE_NR] = { 0, "User Space" },
85 [KERNEL_SPACE_NR] = { (1UL << 63), "Kernel Space" },
86 [LOW_KERNEL_NR] = { 0UL, "Low Kernel Mapping" },
87 [VMALLOC_START_NR] = { 0UL, "vmalloc() Area" },
88 [VMEMMAP_START_NR] = { 0UL, "Vmemmap" },
89#ifdef CONFIG_KASAN
90 /*
91 * These fields get initialized with the (dynamic)
92 * KASAN_SHADOW_{START,END} values in pt_dump_init().
93 */
94 [KASAN_SHADOW_START_NR] = { 0UL, "KASAN shadow" },
95 [KASAN_SHADOW_END_NR] = { 0UL, "KASAN shadow end" },
96#endif
97#ifdef CONFIG_MODIFY_LDT_SYSCALL
98 [LDT_NR] = { 0UL, "LDT remap" },
99#endif
100 [CPU_ENTRY_AREA_NR] = { CPU_ENTRY_AREA_BASE,"CPU entry Area" },
101#ifdef CONFIG_X86_ESPFIX64
102 [ESPFIX_START_NR] = { ESPFIX_BASE_ADDR, "ESPfix Area", 16 },
103#endif
104#ifdef CONFIG_EFI
105 [EFI_END_NR] = { EFI_VA_END, "EFI Runtime Services" },
106#endif
107 [HIGH_KERNEL_NR] = { __START_KERNEL_map, "High Kernel Mapping" },
108 [MODULES_VADDR_NR] = { MODULES_VADDR, "Modules" },
109 [MODULES_END_NR] = { MODULES_END, "End Modules" },
110 [FIXADDR_START_NR] = { FIXADDR_START, "Fixmap Area" },
111 [END_OF_SPACE_NR] = { -1, NULL }
112};
113
114#else /* CONFIG_X86_64 */
115
116enum address_markers_idx {
117 USER_SPACE_NR = 0,
118 KERNEL_SPACE_NR,
119 VMALLOC_START_NR,
120 VMALLOC_END_NR,
121#ifdef CONFIG_HIGHMEM
122 PKMAP_BASE_NR,
123#endif
124 CPU_ENTRY_AREA_NR,
125 FIXADDR_START_NR,
126 END_OF_SPACE_NR,
127};
128
129static struct addr_marker address_markers[] = {
130 [USER_SPACE_NR] = { 0, "User Space" },
131 [KERNEL_SPACE_NR] = { PAGE_OFFSET, "Kernel Mapping" },
132 [VMALLOC_START_NR] = { 0UL, "vmalloc() Area" },
133 [VMALLOC_END_NR] = { 0UL, "vmalloc() End" },
134#ifdef CONFIG_HIGHMEM
135 [PKMAP_BASE_NR] = { 0UL, "Persistent kmap() Area" },
136#endif
137 [CPU_ENTRY_AREA_NR] = { 0UL, "CPU entry area" },
138 [FIXADDR_START_NR] = { 0UL, "Fixmap area" },
139 [END_OF_SPACE_NR] = { -1, NULL }
140};
141
142#endif /* !CONFIG_X86_64 */
143
144/* Multipliers for offsets within the PTEs */
145#define PTE_LEVEL_MULT (PAGE_SIZE)
146#define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
147#define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
148#define P4D_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
149#define PGD_LEVEL_MULT (PTRS_PER_P4D * P4D_LEVEL_MULT)
150
151#define pt_dump_seq_printf(m, to_dmesg, fmt, args...) \
152({ \
153 if (to_dmesg) \
154 printk(KERN_INFO fmt, ##args); \
155 else \
156 if (m) \
157 seq_printf(m, fmt, ##args); \
158})
159
160#define pt_dump_cont_printf(m, to_dmesg, fmt, args...) \
161({ \
162 if (to_dmesg) \
163 printk(KERN_CONT fmt, ##args); \
164 else \
165 if (m) \
166 seq_printf(m, fmt, ##args); \
167})
168
169/*
170 * Print a readable form of a pgprot_t to the seq_file
171 */
172static void printk_prot(struct seq_file *m, pgprot_t prot, int level, bool dmsg)
173{
174 pgprotval_t pr = pgprot_val(prot);
175 static const char * const level_name[] =
176 { "cr3", "pgd", "p4d", "pud", "pmd", "pte" };
177
178 if (!(pr & _PAGE_PRESENT)) {
179 /* Not present */
180 pt_dump_cont_printf(m, dmsg, " ");
181 } else {
182 if (pr & _PAGE_USER)
183 pt_dump_cont_printf(m, dmsg, "USR ");
184 else
185 pt_dump_cont_printf(m, dmsg, " ");
186 if (pr & _PAGE_RW)
187 pt_dump_cont_printf(m, dmsg, "RW ");
188 else
189 pt_dump_cont_printf(m, dmsg, "ro ");
190 if (pr & _PAGE_PWT)
191 pt_dump_cont_printf(m, dmsg, "PWT ");
192 else
193 pt_dump_cont_printf(m, dmsg, " ");
194 if (pr & _PAGE_PCD)
195 pt_dump_cont_printf(m, dmsg, "PCD ");
196 else
197 pt_dump_cont_printf(m, dmsg, " ");
198
199 /* Bit 7 has a different meaning on level 3 vs 4 */
200 if (level <= 4 && pr & _PAGE_PSE)
201 pt_dump_cont_printf(m, dmsg, "PSE ");
202 else
203 pt_dump_cont_printf(m, dmsg, " ");
204 if ((level == 5 && pr & _PAGE_PAT) ||
205 ((level == 4 || level == 3) && pr & _PAGE_PAT_LARGE))
206 pt_dump_cont_printf(m, dmsg, "PAT ");
207 else
208 pt_dump_cont_printf(m, dmsg, " ");
209 if (pr & _PAGE_GLOBAL)
210 pt_dump_cont_printf(m, dmsg, "GLB ");
211 else
212 pt_dump_cont_printf(m, dmsg, " ");
213 if (pr & _PAGE_NX)
214 pt_dump_cont_printf(m, dmsg, "NX ");
215 else
216 pt_dump_cont_printf(m, dmsg, "x ");
217 }
218 pt_dump_cont_printf(m, dmsg, "%s\n", level_name[level]);
219}
220
221/*
222 * On 64 bits, sign-extend the 48 bit address to 64 bit
223 */
224static unsigned long normalize_addr(unsigned long u)
225{
226 int shift;
227 if (!IS_ENABLED(CONFIG_X86_64))
228 return u;
229
230 shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
231 return (signed long)(u << shift) >> shift;
232}
233
234/*
235 * This function gets called on a break in a continuous series
236 * of PTE entries; the next one is different so we need to
237 * print what we collected so far.
238 */
239static void note_page(struct seq_file *m, struct pg_state *st,
240 pgprot_t new_prot, pgprotval_t new_eff, int level)
241{
242 pgprotval_t prot, cur, eff;
243 static const char units[] = "BKMGTPE";
244
245 /*
246 * If we have a "break" in the series, we need to flush the state that
247 * we have now. "break" is either changing perms, levels or
248 * address space marker.
249 */
250 prot = pgprot_val(new_prot);
251 cur = pgprot_val(st->current_prot);
252 eff = st->effective_prot;
253
254 if (!st->level) {
255 /* First entry */
256 st->current_prot = new_prot;
257 st->effective_prot = new_eff;
258 st->level = level;
259 st->marker = address_markers;
260 st->lines = 0;
261 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
262 st->marker->name);
263 } else if (prot != cur || new_eff != eff || level != st->level ||
264 st->current_address >= st->marker[1].start_address) {
265 const char *unit = units;
266 unsigned long delta;
267 int width = sizeof(unsigned long) * 2;
268
269 if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) {
270 WARN_ONCE(1,
271 "x86/mm: Found insecure W+X mapping at address %p/%pS\n",
272 (void *)st->start_address,
273 (void *)st->start_address);
274 st->wx_pages += (st->current_address -
275 st->start_address) / PAGE_SIZE;
276 }
277
278 /*
279 * Now print the actual finished series
280 */
281 if (!st->marker->max_lines ||
282 st->lines < st->marker->max_lines) {
283 pt_dump_seq_printf(m, st->to_dmesg,
284 "0x%0*lx-0x%0*lx ",
285 width, st->start_address,
286 width, st->current_address);
287
288 delta = st->current_address - st->start_address;
289 while (!(delta & 1023) && unit[1]) {
290 delta >>= 10;
291 unit++;
292 }
293 pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ",
294 delta, *unit);
295 printk_prot(m, st->current_prot, st->level,
296 st->to_dmesg);
297 }
298 st->lines++;
299
300 /*
301 * We print markers for special areas of address space,
302 * such as the start of vmalloc space etc.
303 * This helps in the interpretation.
304 */
305 if (st->current_address >= st->marker[1].start_address) {
306 if (st->marker->max_lines &&
307 st->lines > st->marker->max_lines) {
308 unsigned long nskip =
309 st->lines - st->marker->max_lines;
310 pt_dump_seq_printf(m, st->to_dmesg,
311 "... %lu entr%s skipped ... \n",
312 nskip,
313 nskip == 1 ? "y" : "ies");
314 }
315 st->marker++;
316 st->lines = 0;
317 pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
318 st->marker->name);
319 }
320
321 st->start_address = st->current_address;
322 st->current_prot = new_prot;
323 st->effective_prot = new_eff;
324 st->level = level;
325 }
326}
327
328static inline pgprotval_t effective_prot(pgprotval_t prot1, pgprotval_t prot2)
329{
330 return (prot1 & prot2 & (_PAGE_USER | _PAGE_RW)) |
331 ((prot1 | prot2) & _PAGE_NX);
332}
333
334static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr,
335 pgprotval_t eff_in, unsigned long P)
336{
337 int i;
338 pte_t *pte;
339 pgprotval_t prot, eff;
340
341 for (i = 0; i < PTRS_PER_PTE; i++) {
342 st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);
343 pte = pte_offset_map(&addr, st->current_address);
344 prot = pte_flags(*pte);
345 eff = effective_prot(eff_in, prot);
346 note_page(m, st, __pgprot(prot), eff, 5);
347 pte_unmap(pte);
348 }
349}
350#ifdef CONFIG_KASAN
351
352/*
353 * This is an optimization for KASAN=y case. Since all kasan page tables
354 * eventually point to the kasan_zero_page we could call note_page()
355 * right away without walking through lower level page tables. This saves
356 * us dozens of seconds (minutes for 5-level config) while checking for
357 * W+X mapping or reading kernel_page_tables debugfs file.
358 */
359static inline bool kasan_page_table(struct seq_file *m, struct pg_state *st,
360 void *pt)
361{
362 if (__pa(pt) == __pa(kasan_zero_pmd) ||
363 (pgtable_l5_enabled && __pa(pt) == __pa(kasan_zero_p4d)) ||
364 __pa(pt) == __pa(kasan_zero_pud)) {
365 pgprotval_t prot = pte_flags(kasan_zero_pte[0]);
366 note_page(m, st, __pgprot(prot), 0, 5);
367 return true;
368 }
369 return false;
370}
371#else
372static inline bool kasan_page_table(struct seq_file *m, struct pg_state *st,
373 void *pt)
374{
375 return false;
376}
377#endif
378
379#if PTRS_PER_PMD > 1
380
381static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pud_t addr,
382 pgprotval_t eff_in, unsigned long P)
383{
384 int i;
385 pmd_t *start, *pmd_start;
386 pgprotval_t prot, eff;
387
388 pmd_start = start = (pmd_t *)pud_page_vaddr(addr);
389 for (i = 0; i < PTRS_PER_PMD; i++) {
390 st->current_address = normalize_addr(P + i * PMD_LEVEL_MULT);
391 if (!pmd_none(*start)) {
392 prot = pmd_flags(*start);
393 eff = effective_prot(eff_in, prot);
394 if (pmd_large(*start) || !pmd_present(*start)) {
395 note_page(m, st, __pgprot(prot), eff, 4);
396 } else if (!kasan_page_table(m, st, pmd_start)) {
397 walk_pte_level(m, st, *start, eff,
398 P + i * PMD_LEVEL_MULT);
399 }
400 } else
401 note_page(m, st, __pgprot(0), 0, 4);
402 start++;
403 }
404}
405
406#else
407#define walk_pmd_level(m,s,a,e,p) walk_pte_level(m,s,__pmd(pud_val(a)),e,p)
408#define pud_large(a) pmd_large(__pmd(pud_val(a)))
409#define pud_none(a) pmd_none(__pmd(pud_val(a)))
410#endif
411
412#if PTRS_PER_PUD > 1
413
414static void walk_pud_level(struct seq_file *m, struct pg_state *st, p4d_t addr,
415 pgprotval_t eff_in, unsigned long P)
416{
417 int i;
418 pud_t *start, *pud_start;
419 pgprotval_t prot, eff;
420 pud_t *prev_pud = NULL;
421
422 pud_start = start = (pud_t *)p4d_page_vaddr(addr);
423
424 for (i = 0; i < PTRS_PER_PUD; i++) {
425 st->current_address = normalize_addr(P + i * PUD_LEVEL_MULT);
426 if (!pud_none(*start)) {
427 prot = pud_flags(*start);
428 eff = effective_prot(eff_in, prot);
429 if (pud_large(*start) || !pud_present(*start)) {
430 note_page(m, st, __pgprot(prot), eff, 3);
431 } else if (!kasan_page_table(m, st, pud_start)) {
432 walk_pmd_level(m, st, *start, eff,
433 P + i * PUD_LEVEL_MULT);
434 }
435 } else
436 note_page(m, st, __pgprot(0), 0, 3);
437
438 prev_pud = start;
439 start++;
440 }
441}
442
443#else
444#define walk_pud_level(m,s,a,e,p) walk_pmd_level(m,s,__pud(p4d_val(a)),e,p)
445#define p4d_large(a) pud_large(__pud(p4d_val(a)))
446#define p4d_none(a) pud_none(__pud(p4d_val(a)))
447#endif
448
449static void walk_p4d_level(struct seq_file *m, struct pg_state *st, pgd_t addr,
450 pgprotval_t eff_in, unsigned long P)
451{
452 int i;
453 p4d_t *start, *p4d_start;
454 pgprotval_t prot, eff;
455
456 if (PTRS_PER_P4D == 1)
457 return walk_pud_level(m, st, __p4d(pgd_val(addr)), eff_in, P);
458
459 p4d_start = start = (p4d_t *)pgd_page_vaddr(addr);
460
461 for (i = 0; i < PTRS_PER_P4D; i++) {
462 st->current_address = normalize_addr(P + i * P4D_LEVEL_MULT);
463 if (!p4d_none(*start)) {
464 prot = p4d_flags(*start);
465 eff = effective_prot(eff_in, prot);
466 if (p4d_large(*start) || !p4d_present(*start)) {
467 note_page(m, st, __pgprot(prot), eff, 2);
468 } else if (!kasan_page_table(m, st, p4d_start)) {
469 walk_pud_level(m, st, *start, eff,
470 P + i * P4D_LEVEL_MULT);
471 }
472 } else
473 note_page(m, st, __pgprot(0), 0, 2);
474
475 start++;
476 }
477}
478
479#define pgd_large(a) (pgtable_l5_enabled ? pgd_large(a) : p4d_large(__p4d(pgd_val(a))))
480#define pgd_none(a) (pgtable_l5_enabled ? pgd_none(a) : p4d_none(__p4d(pgd_val(a))))
481
482static inline bool is_hypervisor_range(int idx)
483{
484#ifdef CONFIG_X86_64
485 /*
486 * ffff800000000000 - ffff87ffffffffff is reserved for
487 * the hypervisor.
488 */
489 return (idx >= pgd_index(__PAGE_OFFSET) - 16) &&
490 (idx < pgd_index(__PAGE_OFFSET));
491#else
492 return false;
493#endif
494}
495
496static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
497 bool checkwx, bool dmesg)
498{
499#ifdef CONFIG_X86_64
500 pgd_t *start = (pgd_t *) &init_top_pgt;
501#else
502 pgd_t *start = swapper_pg_dir;
503#endif
504 pgprotval_t prot, eff;
505 int i;
506 struct pg_state st = {};
507
508 if (pgd) {
509 start = pgd;
510 st.to_dmesg = dmesg;
511 }
512
513 st.check_wx = checkwx;
514 if (checkwx)
515 st.wx_pages = 0;
516
517 for (i = 0; i < PTRS_PER_PGD; i++) {
518 st.current_address = normalize_addr(i * PGD_LEVEL_MULT);
519 if (!pgd_none(*start) && !is_hypervisor_range(i)) {
520 prot = pgd_flags(*start);
521#ifdef CONFIG_X86_PAE
522 eff = _PAGE_USER | _PAGE_RW;
523#else
524 eff = prot;
525#endif
526 if (pgd_large(*start) || !pgd_present(*start)) {
527 note_page(m, &st, __pgprot(prot), eff, 1);
528 } else {
529 walk_p4d_level(m, &st, *start, eff,
530 i * PGD_LEVEL_MULT);
531 }
532 } else
533 note_page(m, &st, __pgprot(0), 0, 1);
534
535 cond_resched();
536 start++;
537 }
538
539 /* Flush out the last page */
540 st.current_address = normalize_addr(PTRS_PER_PGD*PGD_LEVEL_MULT);
541 note_page(m, &st, __pgprot(0), 0, 0);
542 if (!checkwx)
543 return;
544 if (st.wx_pages)
545 pr_info("x86/mm: Checked W+X mappings: FAILED, %lu W+X pages found.\n",
546 st.wx_pages);
547 else
548 pr_info("x86/mm: Checked W+X mappings: passed, no W+X pages found.\n");
549}
550
551void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
552{
553 ptdump_walk_pgd_level_core(m, pgd, false, true);
554}
555
556void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user)
557{
558#ifdef CONFIG_PAGE_TABLE_ISOLATION
559 if (user && static_cpu_has(X86_FEATURE_PTI))
560 pgd = kernel_to_user_pgdp(pgd);
561#endif
562 ptdump_walk_pgd_level_core(m, pgd, false, false);
563}
564EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs);
565
566static void ptdump_walk_user_pgd_level_checkwx(void)
567{
568#ifdef CONFIG_PAGE_TABLE_ISOLATION
569 pgd_t *pgd = (pgd_t *) &init_top_pgt;
570
571 if (!static_cpu_has(X86_FEATURE_PTI))
572 return;
573
574 pr_info("x86/mm: Checking user space page tables\n");
575 pgd = kernel_to_user_pgdp(pgd);
576 ptdump_walk_pgd_level_core(NULL, pgd, true, false);
577#endif
578}
579
580void ptdump_walk_pgd_level_checkwx(void)
581{
582 ptdump_walk_pgd_level_core(NULL, NULL, true, false);
583 ptdump_walk_user_pgd_level_checkwx();
584}
585
586static int __init pt_dump_init(void)
587{
588 /*
589 * Various markers are not compile-time constants, so assign them
590 * here.
591 */
592#ifdef CONFIG_X86_64
593 address_markers[LOW_KERNEL_NR].start_address = PAGE_OFFSET;
594 address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
595 address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START;
596#ifdef CONFIG_MODIFY_LDT_SYSCALL
597 address_markers[LDT_NR].start_address = LDT_BASE_ADDR;
598#endif
599#ifdef CONFIG_KASAN
600 address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START;
601 address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END;
602#endif
603#endif
604#ifdef CONFIG_X86_32
605 address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
606 address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
607# ifdef CONFIG_HIGHMEM
608 address_markers[PKMAP_BASE_NR].start_address = PKMAP_BASE;
609# endif
610 address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
611 address_markers[CPU_ENTRY_AREA_NR].start_address = CPU_ENTRY_AREA_BASE;
612#endif
613 return 0;
614}
615__initcall(pt_dump_init);