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59c4da86 ZL |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* | |
3 | * Copyright (C) 2019 SiFive | |
4 | */ | |
5 | ||
de22d210 | 6 | #include <linux/efi.h> |
59c4da86 ZL |
7 | #include <linux/init.h> |
8 | #include <linux/debugfs.h> | |
9 | #include <linux/seq_file.h> | |
10 | #include <linux/ptdump.h> | |
11 | ||
12 | #include <asm/ptdump.h> | |
ca5999fd | 13 | #include <linux/pgtable.h> |
59c4da86 ZL |
14 | #include <asm/kasan.h> |
15 | ||
16 | #define pt_dump_seq_printf(m, fmt, args...) \ | |
17 | ({ \ | |
18 | if (m) \ | |
19 | seq_printf(m, fmt, ##args); \ | |
20 | }) | |
21 | ||
22 | #define pt_dump_seq_puts(m, fmt) \ | |
23 | ({ \ | |
24 | if (m) \ | |
25 | seq_printf(m, fmt); \ | |
26 | }) | |
27 | ||
28 | /* | |
29 | * The page dumper groups page table entries of the same type into a single | |
30 | * description. It uses pg_state to track the range information while | |
31 | * iterating over the pte entries. When the continuity is broken it then | |
32 | * dumps out a description of the range. | |
33 | */ | |
34 | struct pg_state { | |
35 | struct ptdump_state ptdump; | |
36 | struct seq_file *seq; | |
37 | const struct addr_marker *marker; | |
38 | unsigned long start_address; | |
39 | unsigned long start_pa; | |
40 | unsigned long last_pa; | |
41 | int level; | |
42 | u64 current_prot; | |
43 | bool check_wx; | |
44 | unsigned long wx_pages; | |
45 | }; | |
46 | ||
47 | /* Address marker */ | |
48 | struct addr_marker { | |
49 | unsigned long start_address; | |
50 | const char *name; | |
51 | }; | |
52 | ||
de22d210 AP |
53 | /* Private information for debugfs */ |
54 | struct ptd_mm_info { | |
55 | struct mm_struct *mm; | |
56 | const struct addr_marker *markers; | |
57 | unsigned long base_addr; | |
58 | unsigned long end; | |
59 | }; | |
60 | ||
59c4da86 ZL |
61 | static struct addr_marker address_markers[] = { |
62 | #ifdef CONFIG_KASAN | |
63 | {KASAN_SHADOW_START, "Kasan shadow start"}, | |
64 | {KASAN_SHADOW_END, "Kasan shadow end"}, | |
65 | #endif | |
66 | {FIXADDR_START, "Fixmap start"}, | |
67 | {FIXADDR_TOP, "Fixmap end"}, | |
68 | {PCI_IO_START, "PCI I/O start"}, | |
69 | {PCI_IO_END, "PCI I/O end"}, | |
70 | #ifdef CONFIG_SPARSEMEM_VMEMMAP | |
71 | {VMEMMAP_START, "vmemmap start"}, | |
72 | {VMEMMAP_END, "vmemmap end"}, | |
73 | #endif | |
74 | {VMALLOC_START, "vmalloc() area"}, | |
75 | {VMALLOC_END, "vmalloc() end"}, | |
76 | {PAGE_OFFSET, "Linear mapping"}, | |
77 | {-1, NULL}, | |
78 | }; | |
79 | ||
de22d210 AP |
80 | static struct ptd_mm_info kernel_ptd_info = { |
81 | .mm = &init_mm, | |
82 | .markers = address_markers, | |
83 | .base_addr = KERN_VIRT_START, | |
84 | .end = ULONG_MAX, | |
85 | }; | |
86 | ||
87 | #ifdef CONFIG_EFI | |
88 | static struct addr_marker efi_addr_markers[] = { | |
89 | { 0, "UEFI runtime start" }, | |
90 | { SZ_1G, "UEFI runtime end" }, | |
91 | { -1, NULL } | |
92 | }; | |
93 | ||
94 | static struct ptd_mm_info efi_ptd_info = { | |
95 | .mm = &efi_mm, | |
96 | .markers = efi_addr_markers, | |
97 | .base_addr = 0, | |
98 | .end = SZ_2G, | |
99 | }; | |
100 | #endif | |
101 | ||
59c4da86 ZL |
102 | /* Page Table Entry */ |
103 | struct prot_bits { | |
104 | u64 mask; | |
105 | u64 val; | |
106 | const char *set; | |
107 | const char *clear; | |
108 | }; | |
109 | ||
110 | static const struct prot_bits pte_bits[] = { | |
111 | { | |
112 | .mask = _PAGE_SOFT, | |
113 | .val = _PAGE_SOFT, | |
114 | .set = "RSW", | |
115 | .clear = " ", | |
116 | }, { | |
117 | .mask = _PAGE_DIRTY, | |
118 | .val = _PAGE_DIRTY, | |
119 | .set = "D", | |
120 | .clear = ".", | |
121 | }, { | |
122 | .mask = _PAGE_ACCESSED, | |
123 | .val = _PAGE_ACCESSED, | |
124 | .set = "A", | |
125 | .clear = ".", | |
126 | }, { | |
127 | .mask = _PAGE_GLOBAL, | |
128 | .val = _PAGE_GLOBAL, | |
129 | .set = "G", | |
130 | .clear = ".", | |
131 | }, { | |
132 | .mask = _PAGE_USER, | |
133 | .val = _PAGE_USER, | |
134 | .set = "U", | |
135 | .clear = ".", | |
136 | }, { | |
137 | .mask = _PAGE_EXEC, | |
138 | .val = _PAGE_EXEC, | |
139 | .set = "X", | |
140 | .clear = ".", | |
141 | }, { | |
142 | .mask = _PAGE_WRITE, | |
143 | .val = _PAGE_WRITE, | |
144 | .set = "W", | |
145 | .clear = ".", | |
146 | }, { | |
147 | .mask = _PAGE_READ, | |
148 | .val = _PAGE_READ, | |
149 | .set = "R", | |
150 | .clear = ".", | |
151 | }, { | |
152 | .mask = _PAGE_PRESENT, | |
153 | .val = _PAGE_PRESENT, | |
154 | .set = "V", | |
155 | .clear = ".", | |
156 | } | |
157 | }; | |
158 | ||
159 | /* Page Level */ | |
160 | struct pg_level { | |
161 | const char *name; | |
162 | u64 mask; | |
163 | }; | |
164 | ||
165 | static struct pg_level pg_level[] = { | |
166 | { /* pgd */ | |
167 | .name = "PGD", | |
168 | }, { /* p4d */ | |
169 | .name = (CONFIG_PGTABLE_LEVELS > 4) ? "P4D" : "PGD", | |
170 | }, { /* pud */ | |
171 | .name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD", | |
172 | }, { /* pmd */ | |
173 | .name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD", | |
174 | }, { /* pte */ | |
175 | .name = "PTE", | |
176 | }, | |
177 | }; | |
178 | ||
179 | static void dump_prot(struct pg_state *st) | |
180 | { | |
181 | unsigned int i; | |
182 | ||
183 | for (i = 0; i < ARRAY_SIZE(pte_bits); i++) { | |
184 | const char *s; | |
185 | ||
186 | if ((st->current_prot & pte_bits[i].mask) == pte_bits[i].val) | |
187 | s = pte_bits[i].set; | |
188 | else | |
189 | s = pte_bits[i].clear; | |
190 | ||
191 | if (s) | |
192 | pt_dump_seq_printf(st->seq, " %s", s); | |
193 | } | |
194 | } | |
195 | ||
196 | #ifdef CONFIG_64BIT | |
197 | #define ADDR_FORMAT "0x%016lx" | |
198 | #else | |
199 | #define ADDR_FORMAT "0x%08lx" | |
200 | #endif | |
201 | static void dump_addr(struct pg_state *st, unsigned long addr) | |
202 | { | |
203 | static const char units[] = "KMGTPE"; | |
204 | const char *unit = units; | |
205 | unsigned long delta; | |
206 | ||
207 | pt_dump_seq_printf(st->seq, ADDR_FORMAT "-" ADDR_FORMAT " ", | |
208 | st->start_address, addr); | |
209 | ||
210 | pt_dump_seq_printf(st->seq, " " ADDR_FORMAT " ", st->start_pa); | |
211 | delta = (addr - st->start_address) >> 10; | |
212 | ||
213 | while (!(delta & 1023) && unit[1]) { | |
214 | delta >>= 10; | |
215 | unit++; | |
216 | } | |
217 | ||
218 | pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit, | |
219 | pg_level[st->level].name); | |
220 | } | |
221 | ||
222 | static void note_prot_wx(struct pg_state *st, unsigned long addr) | |
223 | { | |
224 | if (!st->check_wx) | |
225 | return; | |
226 | ||
227 | if ((st->current_prot & (_PAGE_WRITE | _PAGE_EXEC)) != | |
228 | (_PAGE_WRITE | _PAGE_EXEC)) | |
229 | return; | |
230 | ||
231 | WARN_ONCE(1, "riscv/mm: Found insecure W+X mapping at address %p/%pS\n", | |
232 | (void *)st->start_address, (void *)st->start_address); | |
233 | ||
234 | st->wx_pages += (addr - st->start_address) / PAGE_SIZE; | |
235 | } | |
236 | ||
237 | static void note_page(struct ptdump_state *pt_st, unsigned long addr, | |
99395ee3 | 238 | int level, u64 val) |
59c4da86 ZL |
239 | { |
240 | struct pg_state *st = container_of(pt_st, struct pg_state, ptdump); | |
241 | u64 pa = PFN_PHYS(pte_pfn(__pte(val))); | |
242 | u64 prot = 0; | |
243 | ||
244 | if (level >= 0) | |
245 | prot = val & pg_level[level].mask; | |
246 | ||
247 | if (st->level == -1) { | |
248 | st->level = level; | |
249 | st->current_prot = prot; | |
250 | st->start_address = addr; | |
251 | st->start_pa = pa; | |
252 | st->last_pa = pa; | |
253 | pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); | |
254 | } else if (prot != st->current_prot || | |
255 | level != st->level || addr >= st->marker[1].start_address) { | |
256 | if (st->current_prot) { | |
257 | note_prot_wx(st, addr); | |
258 | dump_addr(st, addr); | |
259 | dump_prot(st); | |
260 | pt_dump_seq_puts(st->seq, "\n"); | |
261 | } | |
262 | ||
263 | while (addr >= st->marker[1].start_address) { | |
264 | st->marker++; | |
265 | pt_dump_seq_printf(st->seq, "---[ %s ]---\n", | |
266 | st->marker->name); | |
267 | } | |
268 | ||
269 | st->start_address = addr; | |
270 | st->start_pa = pa; | |
271 | st->last_pa = pa; | |
272 | st->current_prot = prot; | |
273 | st->level = level; | |
274 | } else { | |
275 | st->last_pa = pa; | |
276 | } | |
277 | } | |
278 | ||
de22d210 | 279 | static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo) |
59c4da86 ZL |
280 | { |
281 | struct pg_state st = { | |
282 | .seq = s, | |
de22d210 | 283 | .marker = pinfo->markers, |
59c4da86 ZL |
284 | .level = -1, |
285 | .ptdump = { | |
286 | .note_page = note_page, | |
287 | .range = (struct ptdump_range[]) { | |
de22d210 | 288 | {pinfo->base_addr, pinfo->end}, |
59c4da86 ZL |
289 | {0, 0} |
290 | } | |
291 | } | |
292 | }; | |
293 | ||
de22d210 | 294 | ptdump_walk_pgd(&st.ptdump, pinfo->mm, NULL); |
59c4da86 ZL |
295 | } |
296 | ||
297 | void ptdump_check_wx(void) | |
298 | { | |
299 | struct pg_state st = { | |
300 | .seq = NULL, | |
301 | .marker = (struct addr_marker[]) { | |
302 | {0, NULL}, | |
303 | {-1, NULL}, | |
304 | }, | |
305 | .level = -1, | |
306 | .check_wx = true, | |
307 | .ptdump = { | |
308 | .note_page = note_page, | |
309 | .range = (struct ptdump_range[]) { | |
310 | {KERN_VIRT_START, ULONG_MAX}, | |
311 | {0, 0} | |
312 | } | |
313 | } | |
314 | }; | |
315 | ||
316 | ptdump_walk_pgd(&st.ptdump, &init_mm, NULL); | |
317 | ||
318 | if (st.wx_pages) | |
319 | pr_warn("Checked W+X mappings: failed, %lu W+X pages found\n", | |
320 | st.wx_pages); | |
321 | else | |
322 | pr_info("Checked W+X mappings: passed, no W+X pages found\n"); | |
323 | } | |
324 | ||
325 | static int ptdump_show(struct seq_file *m, void *v) | |
326 | { | |
de22d210 | 327 | ptdump_walk(m, m->private); |
59c4da86 ZL |
328 | |
329 | return 0; | |
330 | } | |
331 | ||
332 | DEFINE_SHOW_ATTRIBUTE(ptdump); | |
333 | ||
334 | static int ptdump_init(void) | |
335 | { | |
336 | unsigned int i, j; | |
337 | ||
338 | for (i = 0; i < ARRAY_SIZE(pg_level); i++) | |
339 | for (j = 0; j < ARRAY_SIZE(pte_bits); j++) | |
340 | pg_level[i].mask |= pte_bits[j].mask; | |
341 | ||
de22d210 | 342 | debugfs_create_file("kernel_page_tables", 0400, NULL, &kernel_ptd_info, |
59c4da86 | 343 | &ptdump_fops); |
de22d210 AP |
344 | #ifdef CONFIG_EFI |
345 | if (efi_enabled(EFI_RUNTIME_SERVICES)) | |
346 | debugfs_create_file("efi_page_tables", 0400, NULL, &efi_ptd_info, | |
347 | &ptdump_fops); | |
348 | #endif | |
59c4da86 ZL |
349 | |
350 | return 0; | |
351 | } | |
352 | ||
353 | device_initcall(ptdump_init); |