1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
|
// SPDX-License-Identifier: GPL-2.0
#include <linux/sched/task.h>
#include <linux/pgtable.h>
#include <linux/kasan.h>
#include <asm/ctl_reg.h>
#include <asm/pgalloc.h>
#include <asm/facility.h>
#include <asm/sections.h>
#include <asm/physmem_info.h>
#include <asm/maccess.h>
#include <asm/abs_lowcore.h>
#include "decompressor.h"
#include "boot.h"
unsigned long __bootdata_preserved(s390_invalid_asce);
#ifdef CONFIG_PROC_FS
atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]);
#endif
#define init_mm (*(struct mm_struct *)vmlinux.init_mm_off)
#define swapper_pg_dir vmlinux.swapper_pg_dir_off
#define invalid_pg_dir vmlinux.invalid_pg_dir_off
enum populate_mode {
POPULATE_NONE,
POPULATE_DIRECT,
POPULATE_ABS_LOWCORE,
#ifdef CONFIG_KASAN
POPULATE_KASAN_MAP_SHADOW,
POPULATE_KASAN_ZERO_SHADOW,
POPULATE_KASAN_SHALLOW
#endif
};
static void pgtable_populate(unsigned long addr, unsigned long end, enum populate_mode mode);
#ifdef CONFIG_KASAN
#define kasan_early_shadow_page vmlinux.kasan_early_shadow_page_off
#define kasan_early_shadow_pte ((pte_t *)vmlinux.kasan_early_shadow_pte_off)
#define kasan_early_shadow_pmd ((pmd_t *)vmlinux.kasan_early_shadow_pmd_off)
#define kasan_early_shadow_pud ((pud_t *)vmlinux.kasan_early_shadow_pud_off)
#define kasan_early_shadow_p4d ((p4d_t *)vmlinux.kasan_early_shadow_p4d_off)
#define __sha(x) ((unsigned long)kasan_mem_to_shadow((void *)x))
static pte_t pte_z;
static inline void kasan_populate(unsigned long start, unsigned long end, enum populate_mode mode)
{
start = PAGE_ALIGN_DOWN(__sha(start));
end = PAGE_ALIGN(__sha(end));
pgtable_populate(start, end, mode);
}
static void kasan_populate_shadow(void)
{
pmd_t pmd_z = __pmd(__pa(kasan_early_shadow_pte) | _SEGMENT_ENTRY);
pud_t pud_z = __pud(__pa(kasan_early_shadow_pmd) | _REGION3_ENTRY);
p4d_t p4d_z = __p4d(__pa(kasan_early_shadow_pud) | _REGION2_ENTRY);
unsigned long untracked_end;
unsigned long start, end;
int i;
pte_z = __pte(__pa(kasan_early_shadow_page) | pgprot_val(PAGE_KERNEL_RO));
if (!machine.has_nx)
pte_z = clear_pte_bit(pte_z, __pgprot(_PAGE_NOEXEC));
crst_table_init((unsigned long *)kasan_early_shadow_p4d, p4d_val(p4d_z));
crst_table_init((unsigned long *)kasan_early_shadow_pud, pud_val(pud_z));
crst_table_init((unsigned long *)kasan_early_shadow_pmd, pmd_val(pmd_z));
memset64((u64 *)kasan_early_shadow_pte, pte_val(pte_z), PTRS_PER_PTE);
/*
* Current memory layout:
* +- 0 -------------+ +- shadow start -+
* |1:1 ident mapping| /|1/8 of ident map|
* | | / | |
* +-end of ident map+ / +----------------+
* | ... gap ... | / | kasan |
* | | / | zero page |
* +- vmalloc area -+ / | mapping |
* | vmalloc_size | / | (untracked) |
* +- modules vaddr -+ / +----------------+
* | 2Gb |/ | unmapped | allocated per module
* +- shadow start -+ +----------------+
* | 1/8 addr space | | zero pg mapping| (untracked)
* +- shadow end ----+---------+- shadow end ---+
*
* Current memory layout (KASAN_VMALLOC):
* +- 0 -------------+ +- shadow start -+
* |1:1 ident mapping| /|1/8 of ident map|
* | | / | |
* +-end of ident map+ / +----------------+
* | ... gap ... | / | kasan zero page| (untracked)
* | | / | mapping |
* +- vmalloc area -+ / +----------------+
* | vmalloc_size | / |shallow populate|
* +- modules vaddr -+ / +----------------+
* | 2Gb |/ |shallow populate|
* +- shadow start -+ +----------------+
* | 1/8 addr space | | zero pg mapping| (untracked)
* +- shadow end ----+---------+- shadow end ---+
*/
for_each_physmem_usable_range(i, &start, &end)
kasan_populate(start, end, POPULATE_KASAN_MAP_SHADOW);
if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
untracked_end = VMALLOC_START;
/* shallowly populate kasan shadow for vmalloc and modules */
kasan_populate(VMALLOC_START, MODULES_END, POPULATE_KASAN_SHALLOW);
} else {
untracked_end = MODULES_VADDR;
}
/* populate kasan shadow for untracked memory */
kasan_populate(ident_map_size, untracked_end, POPULATE_KASAN_ZERO_SHADOW);
kasan_populate(MODULES_END, _REGION1_SIZE, POPULATE_KASAN_ZERO_SHADOW);
}
static bool kasan_pgd_populate_zero_shadow(pgd_t *pgd, unsigned long addr,
unsigned long end, enum populate_mode mode)
{
if (mode == POPULATE_KASAN_ZERO_SHADOW &&
IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
pgd_populate(&init_mm, pgd, kasan_early_shadow_p4d);
return true;
}
return false;
}
static bool kasan_p4d_populate_zero_shadow(p4d_t *p4d, unsigned long addr,
unsigned long end, enum populate_mode mode)
{
if (mode == POPULATE_KASAN_ZERO_SHADOW &&
IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
p4d_populate(&init_mm, p4d, kasan_early_shadow_pud);
return true;
}
return false;
}
static bool kasan_pud_populate_zero_shadow(pud_t *pud, unsigned long addr,
unsigned long end, enum populate_mode mode)
{
if (mode == POPULATE_KASAN_ZERO_SHADOW &&
IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
pud_populate(&init_mm, pud, kasan_early_shadow_pmd);
return true;
}
return false;
}
static bool kasan_pmd_populate_zero_shadow(pmd_t *pmd, unsigned long addr,
unsigned long end, enum populate_mode mode)
{
if (mode == POPULATE_KASAN_ZERO_SHADOW &&
IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
pmd_populate(&init_mm, pmd, kasan_early_shadow_pte);
return true;
}
return false;
}
static bool kasan_pte_populate_zero_shadow(pte_t *pte, enum populate_mode mode)
{
pte_t entry;
if (mode == POPULATE_KASAN_ZERO_SHADOW) {
set_pte(pte, pte_z);
return true;
}
return false;
}
#else
static inline void kasan_populate_shadow(void) {}
static inline bool kasan_pgd_populate_zero_shadow(pgd_t *pgd, unsigned long addr,
unsigned long end, enum populate_mode mode)
{
return false;
}
static inline bool kasan_p4d_populate_zero_shadow(p4d_t *p4d, unsigned long addr,
unsigned long end, enum populate_mode mode)
{
return false;
}
static inline bool kasan_pud_populate_zero_shadow(pud_t *pud, unsigned long addr,
unsigned long end, enum populate_mode mode)
{
return false;
}
static inline bool kasan_pmd_populate_zero_shadow(pmd_t *pmd, unsigned long addr,
unsigned long end, enum populate_mode mode)
{
return false;
}
static bool kasan_pte_populate_zero_shadow(pte_t *pte, enum populate_mode mode)
{
return false;
}
#endif
/*
* Mimic virt_to_kpte() in lack of init_mm symbol. Skip pmd NULL check though.
*/
static inline pte_t *__virt_to_kpte(unsigned long va)
{
return pte_offset_kernel(pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va), va);
}
static void *boot_crst_alloc(unsigned long val)
{
unsigned long size = PAGE_SIZE << CRST_ALLOC_ORDER;
unsigned long *table;
table = (unsigned long *)physmem_alloc_top_down(RR_VMEM, size, size);
crst_table_init(table, val);
return table;
}
static pte_t *boot_pte_alloc(void)
{
static void *pte_leftover;
pte_t *pte;
/*
* handling pte_leftovers this way helps to avoid memory fragmentation
* during POPULATE_KASAN_MAP_SHADOW when EDAT is off
*/
if (!pte_leftover) {
pte_leftover = (void *)physmem_alloc_top_down(RR_VMEM, PAGE_SIZE, PAGE_SIZE);
pte = pte_leftover + _PAGE_TABLE_SIZE;
} else {
pte = pte_leftover;
pte_leftover = NULL;
}
memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
return pte;
}
static unsigned long _pa(unsigned long addr, unsigned long size, enum populate_mode mode)
{
switch (mode) {
case POPULATE_NONE:
return -1;
case POPULATE_DIRECT:
return addr;
case POPULATE_ABS_LOWCORE:
return __abs_lowcore_pa(addr);
#ifdef CONFIG_KASAN
case POPULATE_KASAN_MAP_SHADOW:
addr = physmem_alloc_top_down(RR_VMEM, size, size);
memset((void *)addr, 0, size);
return addr;
#endif
default:
return -1;
}
}
static bool can_large_pud(pud_t *pu_dir, unsigned long addr, unsigned long end)
{
return machine.has_edat2 &&
IS_ALIGNED(addr, PUD_SIZE) && (end - addr) >= PUD_SIZE;
}
static bool can_large_pmd(pmd_t *pm_dir, unsigned long addr, unsigned long end)
{
return machine.has_edat1 &&
IS_ALIGNED(addr, PMD_SIZE) && (end - addr) >= PMD_SIZE;
}
static void pgtable_pte_populate(pmd_t *pmd, unsigned long addr, unsigned long end,
enum populate_mode mode)
{
unsigned long pages = 0;
pte_t *pte, entry;
pte = pte_offset_kernel(pmd, addr);
for (; addr < end; addr += PAGE_SIZE, pte++) {
if (pte_none(*pte)) {
if (kasan_pte_populate_zero_shadow(pte, mode))
continue;
entry = __pte(_pa(addr, PAGE_SIZE, mode));
entry = set_pte_bit(entry, PAGE_KERNEL);
if (!machine.has_nx)
entry = clear_pte_bit(entry, __pgprot(_PAGE_NOEXEC));
set_pte(pte, entry);
pages++;
}
}
if (mode == POPULATE_DIRECT)
update_page_count(PG_DIRECT_MAP_4K, pages);
}
static void pgtable_pmd_populate(pud_t *pud, unsigned long addr, unsigned long end,
enum populate_mode mode)
{
unsigned long next, pages = 0;
pmd_t *pmd, entry;
pte_t *pte;
pmd = pmd_offset(pud, addr);
for (; addr < end; addr = next, pmd++) {
next = pmd_addr_end(addr, end);
if (pmd_none(*pmd)) {
if (kasan_pmd_populate_zero_shadow(pmd, addr, next, mode))
continue;
if (can_large_pmd(pmd, addr, next)) {
entry = __pmd(_pa(addr, _SEGMENT_SIZE, mode));
entry = set_pmd_bit(entry, SEGMENT_KERNEL);
if (!machine.has_nx)
entry = clear_pmd_bit(entry, __pgprot(_SEGMENT_ENTRY_NOEXEC));
set_pmd(pmd, entry);
pages++;
continue;
}
pte = boot_pte_alloc();
pmd_populate(&init_mm, pmd, pte);
} else if (pmd_large(*pmd)) {
continue;
}
pgtable_pte_populate(pmd, addr, next, mode);
}
if (mode == POPULATE_DIRECT)
update_page_count(PG_DIRECT_MAP_1M, pages);
}
static void pgtable_pud_populate(p4d_t *p4d, unsigned long addr, unsigned long end,
enum populate_mode mode)
{
unsigned long next, pages = 0;
pud_t *pud, entry;
pmd_t *pmd;
pud = pud_offset(p4d, addr);
for (; addr < end; addr = next, pud++) {
next = pud_addr_end(addr, end);
if (pud_none(*pud)) {
if (kasan_pud_populate_zero_shadow(pud, addr, next, mode))
continue;
if (can_large_pud(pud, addr, next)) {
entry = __pud(_pa(addr, _REGION3_SIZE, mode));
entry = set_pud_bit(entry, REGION3_KERNEL);
if (!machine.has_nx)
entry = clear_pud_bit(entry, __pgprot(_REGION_ENTRY_NOEXEC));
set_pud(pud, entry);
pages++;
continue;
}
pmd = boot_crst_alloc(_SEGMENT_ENTRY_EMPTY);
pud_populate(&init_mm, pud, pmd);
} else if (pud_large(*pud)) {
continue;
}
pgtable_pmd_populate(pud, addr, next, mode);
}
if (mode == POPULATE_DIRECT)
update_page_count(PG_DIRECT_MAP_2G, pages);
}
static void pgtable_p4d_populate(pgd_t *pgd, unsigned long addr, unsigned long end,
enum populate_mode mode)
{
unsigned long next;
p4d_t *p4d;
pud_t *pud;
p4d = p4d_offset(pgd, addr);
for (; addr < end; addr = next, p4d++) {
next = p4d_addr_end(addr, end);
if (p4d_none(*p4d)) {
if (kasan_p4d_populate_zero_shadow(p4d, addr, next, mode))
continue;
pud = boot_crst_alloc(_REGION3_ENTRY_EMPTY);
p4d_populate(&init_mm, p4d, pud);
}
pgtable_pud_populate(p4d, addr, next, mode);
}
}
static void pgtable_populate(unsigned long addr, unsigned long end, enum populate_mode mode)
{
unsigned long next;
pgd_t *pgd;
p4d_t *p4d;
pgd = pgd_offset(&init_mm, addr);
for (; addr < end; addr = next, pgd++) {
next = pgd_addr_end(addr, end);
if (pgd_none(*pgd)) {
if (kasan_pgd_populate_zero_shadow(pgd, addr, next, mode))
continue;
p4d = boot_crst_alloc(_REGION2_ENTRY_EMPTY);
pgd_populate(&init_mm, pgd, p4d);
}
#ifdef CONFIG_KASAN
if (mode == POPULATE_KASAN_SHALLOW)
continue;
#endif
pgtable_p4d_populate(pgd, addr, next, mode);
}
}
void setup_vmem(unsigned long asce_limit)
{
unsigned long start, end;
unsigned long asce_type;
unsigned long asce_bits;
int i;
if (asce_limit == _REGION1_SIZE) {
asce_type = _REGION2_ENTRY_EMPTY;
asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
} else {
asce_type = _REGION3_ENTRY_EMPTY;
asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
}
s390_invalid_asce = invalid_pg_dir | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
crst_table_init((unsigned long *)swapper_pg_dir, asce_type);
crst_table_init((unsigned long *)invalid_pg_dir, _REGION3_ENTRY_EMPTY);
/*
* To allow prefixing the lowcore must be mapped with 4KB pages.
* To prevent creation of a large page at address 0 first map
* the lowcore and create the identity mapping only afterwards.
*/
pgtable_populate(0, sizeof(struct lowcore), POPULATE_DIRECT);
for_each_physmem_usable_range(i, &start, &end)
pgtable_populate(start, end, POPULATE_DIRECT);
pgtable_populate(__abs_lowcore, __abs_lowcore + sizeof(struct lowcore),
POPULATE_ABS_LOWCORE);
pgtable_populate(__memcpy_real_area, __memcpy_real_area + PAGE_SIZE,
POPULATE_NONE);
memcpy_real_ptep = __virt_to_kpte(__memcpy_real_area);
kasan_populate_shadow();
S390_lowcore.kernel_asce = swapper_pg_dir | asce_bits;
S390_lowcore.user_asce = s390_invalid_asce;
__ctl_load(S390_lowcore.kernel_asce, 1, 1);
__ctl_load(S390_lowcore.user_asce, 7, 7);
__ctl_load(S390_lowcore.kernel_asce, 13, 13);
init_mm.context.asce = S390_lowcore.kernel_asce;
}
|