1
2#include <linux/seq_file.h>
3#include <linux/debugfs.h>
4#include <linux/sched.h>
5#include <linux/mm.h>
6#include <linux/kasan.h>
7#include <asm/kasan.h>
8#include <asm/sections.h>
9
10static unsigned long max_addr;
11
12struct addr_marker {
13 unsigned long start_address;
14 const char *name;
15};
16
17enum address_markers_idx {
18 IDENTITY_NR = 0,
19 KERNEL_START_NR,
20 KERNEL_END_NR,
21#ifdef CONFIG_KASAN
22 KASAN_SHADOW_START_NR,
23 KASAN_SHADOW_END_NR,
24#endif
25 VMEMMAP_NR,
26 VMALLOC_NR,
27 MODULES_NR,
28};
29
30static struct addr_marker address_markers[] = {
31 [IDENTITY_NR] = {0, "Identity Mapping"},
32 [KERNEL_START_NR] = {(unsigned long)_stext, "Kernel Image Start"},
33 [KERNEL_END_NR] = {(unsigned long)_end, "Kernel Image End"},
34#ifdef CONFIG_KASAN
35 [KASAN_SHADOW_START_NR] = {KASAN_SHADOW_START, "Kasan Shadow Start"},
36 [KASAN_SHADOW_END_NR] = {KASAN_SHADOW_END, "Kasan Shadow End"},
37#endif
38 [VMEMMAP_NR] = {0, "vmemmap Area"},
39 [VMALLOC_NR] = {0, "vmalloc Area"},
40 [MODULES_NR] = {0, "Modules Area"},
41 { -1, NULL }
42};
43
44struct pg_state {
45 int level;
46 unsigned int current_prot;
47 unsigned long start_address;
48 unsigned long current_address;
49 const struct addr_marker *marker;
50};
51
52static void print_prot(struct seq_file *m, unsigned int pr, int level)
53{
54 static const char * const level_name[] =
55 { "ASCE", "PGD", "PUD", "PMD", "PTE" };
56
57 seq_printf(m, "%s ", level_name[level]);
58 if (pr & _PAGE_INVALID) {
59 seq_printf(m, "I\n");
60 return;
61 }
62 seq_puts(m, (pr & _PAGE_PROTECT) ? "RO " : "RW ");
63 seq_puts(m, (pr & _PAGE_NOEXEC) ? "NX\n" : "X\n");
64}
65
66static void note_page(struct seq_file *m, struct pg_state *st,
67 unsigned int new_prot, int level)
68{
69 static const char units[] = "KMGTPE";
70 int width = sizeof(unsigned long) * 2;
71 const char *unit = units;
72 unsigned int prot, cur;
73 unsigned long delta;
74
75
76
77
78
79
80 prot = new_prot;
81 cur = st->current_prot;
82
83 if (!st->level) {
84
85 st->current_prot = new_prot;
86 st->level = level;
87 st->marker = address_markers;
88 seq_printf(m, "---[ %s ]---\n", st->marker->name);
89 } else if (prot != cur || level != st->level ||
90 st->current_address >= st->marker[1].start_address) {
91
92 seq_printf(m, "0x%0*lx-0x%0*lx ",
93 width, st->start_address,
94 width, st->current_address);
95 delta = (st->current_address - st->start_address) >> 10;
96 while (!(delta & 0x3ff) && unit[1]) {
97 delta >>= 10;
98 unit++;
99 }
100 seq_printf(m, "%9lu%c ", delta, *unit);
101 print_prot(m, st->current_prot, st->level);
102 while (st->current_address >= st->marker[1].start_address) {
103 st->marker++;
104 seq_printf(m, "---[ %s ]---\n", st->marker->name);
105 }
106 st->start_address = st->current_address;
107 st->current_prot = new_prot;
108 st->level = level;
109 }
110}
111
112#ifdef CONFIG_KASAN
113static void note_kasan_early_shadow_page(struct seq_file *m,
114 struct pg_state *st)
115{
116 unsigned int prot;
117
118 prot = pte_val(*kasan_early_shadow_pte) &
119 (_PAGE_PROTECT | _PAGE_INVALID | _PAGE_NOEXEC);
120 note_page(m, st, prot, 4);
121}
122#endif
123
124
125
126
127
128
129
130
131
132static void walk_pte_level(struct seq_file *m, struct pg_state *st,
133 pmd_t *pmd, unsigned long addr)
134{
135 unsigned int prot;
136 pte_t *pte;
137 int i;
138
139 for (i = 0; i < PTRS_PER_PTE && addr < max_addr; i++) {
140 st->current_address = addr;
141 pte = pte_offset_kernel(pmd, addr);
142 prot = pte_val(*pte) &
143 (_PAGE_PROTECT | _PAGE_INVALID | _PAGE_NOEXEC);
144 note_page(m, st, prot, 4);
145 addr += PAGE_SIZE;
146 }
147}
148
149static void walk_pmd_level(struct seq_file *m, struct pg_state *st,
150 pud_t *pud, unsigned long addr)
151{
152 unsigned int prot;
153 pmd_t *pmd;
154 int i;
155
156#ifdef CONFIG_KASAN
157 if ((pud_val(*pud) & PAGE_MASK) == __pa(kasan_early_shadow_pmd)) {
158 note_kasan_early_shadow_page(m, st);
159 return;
160 }
161#endif
162
163 pmd = pmd_offset(pud, addr);
164 for (i = 0; i < PTRS_PER_PMD && addr < max_addr; i++, pmd++) {
165 st->current_address = addr;
166 if (!pmd_none(*pmd)) {
167 if (pmd_large(*pmd)) {
168 prot = pmd_val(*pmd) &
169 (_SEGMENT_ENTRY_PROTECT |
170 _SEGMENT_ENTRY_NOEXEC);
171 note_page(m, st, prot, 3);
172 } else
173 walk_pte_level(m, st, pmd, addr);
174 } else
175 note_page(m, st, _PAGE_INVALID, 3);
176 addr += PMD_SIZE;
177 }
178}
179
180static void walk_pud_level(struct seq_file *m, struct pg_state *st,
181 p4d_t *p4d, unsigned long addr)
182{
183 unsigned int prot;
184 pud_t *pud;
185 int i;
186
187#ifdef CONFIG_KASAN
188 if ((p4d_val(*p4d) & PAGE_MASK) == __pa(kasan_early_shadow_pud)) {
189 note_kasan_early_shadow_page(m, st);
190 return;
191 }
192#endif
193
194 pud = pud_offset(p4d, addr);
195 for (i = 0; i < PTRS_PER_PUD && addr < max_addr; i++, pud++) {
196 st->current_address = addr;
197 if (!pud_none(*pud))
198 if (pud_large(*pud)) {
199 prot = pud_val(*pud) &
200 (_REGION_ENTRY_PROTECT |
201 _REGION_ENTRY_NOEXEC);
202 note_page(m, st, prot, 2);
203 } else
204 walk_pmd_level(m, st, pud, addr);
205 else
206 note_page(m, st, _PAGE_INVALID, 2);
207 addr += PUD_SIZE;
208 }
209}
210
211static void walk_p4d_level(struct seq_file *m, struct pg_state *st,
212 pgd_t *pgd, unsigned long addr)
213{
214 p4d_t *p4d;
215 int i;
216
217#ifdef CONFIG_KASAN
218 if ((pgd_val(*pgd) & PAGE_MASK) == __pa(kasan_early_shadow_p4d)) {
219 note_kasan_early_shadow_page(m, st);
220 return;
221 }
222#endif
223
224 p4d = p4d_offset(pgd, addr);
225 for (i = 0; i < PTRS_PER_P4D && addr < max_addr; i++, p4d++) {
226 st->current_address = addr;
227 if (!p4d_none(*p4d))
228 walk_pud_level(m, st, p4d, addr);
229 else
230 note_page(m, st, _PAGE_INVALID, 2);
231 addr += P4D_SIZE;
232 }
233}
234
235static void walk_pgd_level(struct seq_file *m)
236{
237 unsigned long addr = 0;
238 struct pg_state st;
239 pgd_t *pgd;
240 int i;
241
242 memset(&st, 0, sizeof(st));
243 for (i = 0; i < PTRS_PER_PGD && addr < max_addr; i++) {
244 st.current_address = addr;
245 pgd = pgd_offset_k(addr);
246 if (!pgd_none(*pgd))
247 walk_p4d_level(m, &st, pgd, addr);
248 else
249 note_page(m, &st, _PAGE_INVALID, 1);
250 addr += PGDIR_SIZE;
251 cond_resched();
252 }
253
254 st.current_address = max_addr;
255 note_page(m, &st, 0, 0);
256}
257
258static int ptdump_show(struct seq_file *m, void *v)
259{
260 walk_pgd_level(m);
261 return 0;
262}
263
264static int ptdump_open(struct inode *inode, struct file *filp)
265{
266 return single_open(filp, ptdump_show, NULL);
267}
268
269static const struct file_operations ptdump_fops = {
270 .open = ptdump_open,
271 .read = seq_read,
272 .llseek = seq_lseek,
273 .release = single_release,
274};
275
276static int pt_dump_init(void)
277{
278
279
280
281
282
283 max_addr = (S390_lowcore.kernel_asce & _REGION_ENTRY_TYPE_MASK) >> 2;
284 max_addr = 1UL << (max_addr * 11 + 31);
285 address_markers[MODULES_NR].start_address = MODULES_VADDR;
286 address_markers[VMEMMAP_NR].start_address = (unsigned long) vmemmap;
287 address_markers[VMALLOC_NR].start_address = VMALLOC_START;
288 debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, &ptdump_fops);
289 return 0;
290}
291device_initcall(pt_dump_init);
292
