1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6 #include <linux/mm.h>
7 #include <linux/module.h>
8 #include <linux/sched/signal.h>
9
10 #include <asm/tlbflush.h>
11 #include <as-layout.h>
12 #include <mem_user.h>
13 #include <os.h>
14 #include <skas.h>
15 #include <kern_util.h>
16
17 struct host_vm_change {
18 struct host_vm_op {
19 enum { NONE, MMAP, MUNMAP, MPROTECT } type;
20 union {
21 struct {
22 unsigned long addr;
23 unsigned long len;
24 unsigned int prot;
25 int fd;
26 __u64 offset;
27 } mmap;
28 struct {
29 unsigned long addr;
30 unsigned long len;
31 } munmap;
32 struct {
33 unsigned long addr;
34 unsigned long len;
35 unsigned int prot;
36 } mprotect;
37 } u;
38 } ops[1];
39 int userspace;
40 int index;
41 struct mm_struct *mm;
42 void *data;
43 int force;
44 };
45
46 #define INIT_HVC(mm, force, userspace) \
47 ((struct host_vm_change) \
48 { .ops = { { .type = NONE } }, \
49 .mm = mm, \
50 .data = NULL, \
51 .userspace = userspace, \
52 .index = 0, \
53 .force = force })
54
report_enomem(void)55 static void report_enomem(void)
56 {
57 printk(KERN_ERR "UML ran out of memory on the host side! "
58 "This can happen due to a memory limitation or "
59 "vm.max_map_count has been reached.\n");
60 }
61
do_ops(struct host_vm_change * hvc,int end,int finished)62 static int do_ops(struct host_vm_change *hvc, int end,
63 int finished)
64 {
65 struct host_vm_op *op;
66 int i, ret = 0;
67
68 for (i = 0; i < end && !ret; i++) {
69 op = &hvc->ops[i];
70 switch (op->type) {
71 case MMAP:
72 if (hvc->userspace)
73 ret = map(&hvc->mm->context.id, op->u.mmap.addr,
74 op->u.mmap.len, op->u.mmap.prot,
75 op->u.mmap.fd,
76 op->u.mmap.offset, finished,
77 &hvc->data);
78 else
79 map_memory(op->u.mmap.addr, op->u.mmap.offset,
80 op->u.mmap.len, 1, 1, 1);
81 break;
82 case MUNMAP:
83 if (hvc->userspace)
84 ret = unmap(&hvc->mm->context.id,
85 op->u.munmap.addr,
86 op->u.munmap.len, finished,
87 &hvc->data);
88 else
89 ret = os_unmap_memory(
90 (void *) op->u.munmap.addr,
91 op->u.munmap.len);
92
93 break;
94 case MPROTECT:
95 if (hvc->userspace)
96 ret = protect(&hvc->mm->context.id,
97 op->u.mprotect.addr,
98 op->u.mprotect.len,
99 op->u.mprotect.prot,
100 finished, &hvc->data);
101 else
102 ret = os_protect_memory(
103 (void *) op->u.mprotect.addr,
104 op->u.mprotect.len,
105 1, 1, 1);
106 break;
107 default:
108 printk(KERN_ERR "Unknown op type %d in do_ops\n",
109 op->type);
110 BUG();
111 break;
112 }
113 }
114
115 if (ret == -ENOMEM)
116 report_enomem();
117
118 return ret;
119 }
120
add_mmap(unsigned long virt,unsigned long phys,unsigned long len,unsigned int prot,struct host_vm_change * hvc)121 static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
122 unsigned int prot, struct host_vm_change *hvc)
123 {
124 __u64 offset;
125 struct host_vm_op *last;
126 int fd = -1, ret = 0;
127
128 if (hvc->userspace)
129 fd = phys_mapping(phys, &offset);
130 else
131 offset = phys;
132 if (hvc->index != 0) {
133 last = &hvc->ops[hvc->index - 1];
134 if ((last->type == MMAP) &&
135 (last->u.mmap.addr + last->u.mmap.len == virt) &&
136 (last->u.mmap.prot == prot) && (last->u.mmap.fd == fd) &&
137 (last->u.mmap.offset + last->u.mmap.len == offset)) {
138 last->u.mmap.len += len;
139 return 0;
140 }
141 }
142
143 if (hvc->index == ARRAY_SIZE(hvc->ops)) {
144 ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
145 hvc->index = 0;
146 }
147
148 hvc->ops[hvc->index++] = ((struct host_vm_op)
149 { .type = MMAP,
150 .u = { .mmap = { .addr = virt,
151 .len = len,
152 .prot = prot,
153 .fd = fd,
154 .offset = offset }
155 } });
156 return ret;
157 }
158
add_munmap(unsigned long addr,unsigned long len,struct host_vm_change * hvc)159 static int add_munmap(unsigned long addr, unsigned long len,
160 struct host_vm_change *hvc)
161 {
162 struct host_vm_op *last;
163 int ret = 0;
164
165 if ((addr >= STUB_START) && (addr < STUB_END))
166 return -EINVAL;
167
168 if (hvc->index != 0) {
169 last = &hvc->ops[hvc->index - 1];
170 if ((last->type == MUNMAP) &&
171 (last->u.munmap.addr + last->u.mmap.len == addr)) {
172 last->u.munmap.len += len;
173 return 0;
174 }
175 }
176
177 if (hvc->index == ARRAY_SIZE(hvc->ops)) {
178 ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
179 hvc->index = 0;
180 }
181
182 hvc->ops[hvc->index++] = ((struct host_vm_op)
183 { .type = MUNMAP,
184 .u = { .munmap = { .addr = addr,
185 .len = len } } });
186 return ret;
187 }
188
add_mprotect(unsigned long addr,unsigned long len,unsigned int prot,struct host_vm_change * hvc)189 static int add_mprotect(unsigned long addr, unsigned long len,
190 unsigned int prot, struct host_vm_change *hvc)
191 {
192 struct host_vm_op *last;
193 int ret = 0;
194
195 if (hvc->index != 0) {
196 last = &hvc->ops[hvc->index - 1];
197 if ((last->type == MPROTECT) &&
198 (last->u.mprotect.addr + last->u.mprotect.len == addr) &&
199 (last->u.mprotect.prot == prot)) {
200 last->u.mprotect.len += len;
201 return 0;
202 }
203 }
204
205 if (hvc->index == ARRAY_SIZE(hvc->ops)) {
206 ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
207 hvc->index = 0;
208 }
209
210 hvc->ops[hvc->index++] = ((struct host_vm_op)
211 { .type = MPROTECT,
212 .u = { .mprotect = { .addr = addr,
213 .len = len,
214 .prot = prot } } });
215 return ret;
216 }
217
218 #define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))
219
update_pte_range(pmd_t * pmd,unsigned long addr,unsigned long end,struct host_vm_change * hvc)220 static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
221 unsigned long end,
222 struct host_vm_change *hvc)
223 {
224 pte_t *pte;
225 int r, w, x, prot, ret = 0;
226
227 pte = pte_offset_kernel(pmd, addr);
228 do {
229 if ((addr >= STUB_START) && (addr < STUB_END))
230 continue;
231
232 r = pte_read(*pte);
233 w = pte_write(*pte);
234 x = pte_exec(*pte);
235 if (!pte_young(*pte)) {
236 r = 0;
237 w = 0;
238 } else if (!pte_dirty(*pte))
239 w = 0;
240
241 prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
242 (x ? UM_PROT_EXEC : 0));
243 if (hvc->force || pte_newpage(*pte)) {
244 if (pte_present(*pte)) {
245 if (pte_newpage(*pte))
246 ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
247 PAGE_SIZE, prot, hvc);
248 } else
249 ret = add_munmap(addr, PAGE_SIZE, hvc);
250 } else if (pte_newprot(*pte))
251 ret = add_mprotect(addr, PAGE_SIZE, prot, hvc);
252 *pte = pte_mkuptodate(*pte);
253 } while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret));
254 return ret;
255 }
256
update_pmd_range(pud_t * pud,unsigned long addr,unsigned long end,struct host_vm_change * hvc)257 static inline int update_pmd_range(pud_t *pud, unsigned long addr,
258 unsigned long end,
259 struct host_vm_change *hvc)
260 {
261 pmd_t *pmd;
262 unsigned long next;
263 int ret = 0;
264
265 pmd = pmd_offset(pud, addr);
266 do {
267 next = pmd_addr_end(addr, end);
268 if (!pmd_present(*pmd)) {
269 if (hvc->force || pmd_newpage(*pmd)) {
270 ret = add_munmap(addr, next - addr, hvc);
271 pmd_mkuptodate(*pmd);
272 }
273 }
274 else ret = update_pte_range(pmd, addr, next, hvc);
275 } while (pmd++, addr = next, ((addr < end) && !ret));
276 return ret;
277 }
278
update_pud_range(p4d_t * p4d,unsigned long addr,unsigned long end,struct host_vm_change * hvc)279 static inline int update_pud_range(p4d_t *p4d, unsigned long addr,
280 unsigned long end,
281 struct host_vm_change *hvc)
282 {
283 pud_t *pud;
284 unsigned long next;
285 int ret = 0;
286
287 pud = pud_offset(p4d, addr);
288 do {
289 next = pud_addr_end(addr, end);
290 if (!pud_present(*pud)) {
291 if (hvc->force || pud_newpage(*pud)) {
292 ret = add_munmap(addr, next - addr, hvc);
293 pud_mkuptodate(*pud);
294 }
295 }
296 else ret = update_pmd_range(pud, addr, next, hvc);
297 } while (pud++, addr = next, ((addr < end) && !ret));
298 return ret;
299 }
300
update_p4d_range(pgd_t * pgd,unsigned long addr,unsigned long end,struct host_vm_change * hvc)301 static inline int update_p4d_range(pgd_t *pgd, unsigned long addr,
302 unsigned long end,
303 struct host_vm_change *hvc)
304 {
305 p4d_t *p4d;
306 unsigned long next;
307 int ret = 0;
308
309 p4d = p4d_offset(pgd, addr);
310 do {
311 next = p4d_addr_end(addr, end);
312 if (!p4d_present(*p4d)) {
313 if (hvc->force || p4d_newpage(*p4d)) {
314 ret = add_munmap(addr, next - addr, hvc);
315 p4d_mkuptodate(*p4d);
316 }
317 } else
318 ret = update_pud_range(p4d, addr, next, hvc);
319 } while (p4d++, addr = next, ((addr < end) && !ret));
320 return ret;
321 }
322
fix_range_common(struct mm_struct * mm,unsigned long start_addr,unsigned long end_addr,int force)323 void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
324 unsigned long end_addr, int force)
325 {
326 pgd_t *pgd;
327 struct host_vm_change hvc;
328 unsigned long addr = start_addr, next;
329 int ret = 0, userspace = 1;
330
331 hvc = INIT_HVC(mm, force, userspace);
332 pgd = pgd_offset(mm, addr);
333 do {
334 next = pgd_addr_end(addr, end_addr);
335 if (!pgd_present(*pgd)) {
336 if (force || pgd_newpage(*pgd)) {
337 ret = add_munmap(addr, next - addr, &hvc);
338 pgd_mkuptodate(*pgd);
339 }
340 } else
341 ret = update_p4d_range(pgd, addr, next, &hvc);
342 } while (pgd++, addr = next, ((addr < end_addr) && !ret));
343
344 if (!ret)
345 ret = do_ops(&hvc, hvc.index, 1);
346
347 /* This is not an else because ret is modified above */
348 if (ret) {
349 printk(KERN_ERR "fix_range_common: failed, killing current "
350 "process: %d\n", task_tgid_vnr(current));
351 /* We are under mmap_lock, release it such that current can terminate */
352 mmap_write_unlock(current->mm);
353 force_sig(SIGKILL);
354 do_signal(¤t->thread.regs);
355 }
356 }
357
flush_tlb_kernel_range_common(unsigned long start,unsigned long end)358 static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
359 {
360 struct mm_struct *mm;
361 pgd_t *pgd;
362 p4d_t *p4d;
363 pud_t *pud;
364 pmd_t *pmd;
365 pte_t *pte;
366 unsigned long addr, last;
367 int updated = 0, err = 0, force = 0, userspace = 0;
368 struct host_vm_change hvc;
369
370 mm = &init_mm;
371 hvc = INIT_HVC(mm, force, userspace);
372 for (addr = start; addr < end;) {
373 pgd = pgd_offset(mm, addr);
374 if (!pgd_present(*pgd)) {
375 last = ADD_ROUND(addr, PGDIR_SIZE);
376 if (last > end)
377 last = end;
378 if (pgd_newpage(*pgd)) {
379 updated = 1;
380 err = add_munmap(addr, last - addr, &hvc);
381 if (err < 0)
382 panic("munmap failed, errno = %d\n",
383 -err);
384 }
385 addr = last;
386 continue;
387 }
388
389 p4d = p4d_offset(pgd, addr);
390 if (!p4d_present(*p4d)) {
391 last = ADD_ROUND(addr, P4D_SIZE);
392 if (last > end)
393 last = end;
394 if (p4d_newpage(*p4d)) {
395 updated = 1;
396 err = add_munmap(addr, last - addr, &hvc);
397 if (err < 0)
398 panic("munmap failed, errno = %d\n",
399 -err);
400 }
401 addr = last;
402 continue;
403 }
404
405 pud = pud_offset(p4d, addr);
406 if (!pud_present(*pud)) {
407 last = ADD_ROUND(addr, PUD_SIZE);
408 if (last > end)
409 last = end;
410 if (pud_newpage(*pud)) {
411 updated = 1;
412 err = add_munmap(addr, last - addr, &hvc);
413 if (err < 0)
414 panic("munmap failed, errno = %d\n",
415 -err);
416 }
417 addr = last;
418 continue;
419 }
420
421 pmd = pmd_offset(pud, addr);
422 if (!pmd_present(*pmd)) {
423 last = ADD_ROUND(addr, PMD_SIZE);
424 if (last > end)
425 last = end;
426 if (pmd_newpage(*pmd)) {
427 updated = 1;
428 err = add_munmap(addr, last - addr, &hvc);
429 if (err < 0)
430 panic("munmap failed, errno = %d\n",
431 -err);
432 }
433 addr = last;
434 continue;
435 }
436
437 pte = pte_offset_kernel(pmd, addr);
438 if (!pte_present(*pte) || pte_newpage(*pte)) {
439 updated = 1;
440 err = add_munmap(addr, PAGE_SIZE, &hvc);
441 if (err < 0)
442 panic("munmap failed, errno = %d\n",
443 -err);
444 if (pte_present(*pte))
445 err = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
446 PAGE_SIZE, 0, &hvc);
447 }
448 else if (pte_newprot(*pte)) {
449 updated = 1;
450 err = add_mprotect(addr, PAGE_SIZE, 0, &hvc);
451 }
452 addr += PAGE_SIZE;
453 }
454 if (!err)
455 err = do_ops(&hvc, hvc.index, 1);
456
457 if (err < 0)
458 panic("flush_tlb_kernel failed, errno = %d\n", err);
459 return updated;
460 }
461
flush_tlb_page(struct vm_area_struct * vma,unsigned long address)462 void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
463 {
464 pgd_t *pgd;
465 p4d_t *p4d;
466 pud_t *pud;
467 pmd_t *pmd;
468 pte_t *pte;
469 struct mm_struct *mm = vma->vm_mm;
470 void *flush = NULL;
471 int r, w, x, prot, err = 0;
472 struct mm_id *mm_id;
473
474 address &= PAGE_MASK;
475 pgd = pgd_offset(mm, address);
476 if (!pgd_present(*pgd))
477 goto kill;
478
479 p4d = p4d_offset(pgd, address);
480 if (!p4d_present(*p4d))
481 goto kill;
482
483 pud = pud_offset(p4d, address);
484 if (!pud_present(*pud))
485 goto kill;
486
487 pmd = pmd_offset(pud, address);
488 if (!pmd_present(*pmd))
489 goto kill;
490
491 pte = pte_offset_kernel(pmd, address);
492
493 r = pte_read(*pte);
494 w = pte_write(*pte);
495 x = pte_exec(*pte);
496 if (!pte_young(*pte)) {
497 r = 0;
498 w = 0;
499 } else if (!pte_dirty(*pte)) {
500 w = 0;
501 }
502
503 mm_id = &mm->context.id;
504 prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
505 (x ? UM_PROT_EXEC : 0));
506 if (pte_newpage(*pte)) {
507 if (pte_present(*pte)) {
508 unsigned long long offset;
509 int fd;
510
511 fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
512 err = map(mm_id, address, PAGE_SIZE, prot, fd, offset,
513 1, &flush);
514 }
515 else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
516 }
517 else if (pte_newprot(*pte))
518 err = protect(mm_id, address, PAGE_SIZE, prot, 1, &flush);
519
520 if (err) {
521 if (err == -ENOMEM)
522 report_enomem();
523
524 goto kill;
525 }
526
527 *pte = pte_mkuptodate(*pte);
528
529 return;
530
531 kill:
532 printk(KERN_ERR "Failed to flush page for address 0x%lx\n", address);
533 force_sig(SIGKILL);
534 }
535
flush_tlb_all(void)536 void flush_tlb_all(void)
537 {
538 /*
539 * Don't bother flushing if this address space is about to be
540 * destroyed.
541 */
542 if (atomic_read(¤t->mm->mm_users) == 0)
543 return;
544
545 flush_tlb_mm(current->mm);
546 }
547
flush_tlb_kernel_range(unsigned long start,unsigned long end)548 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
549 {
550 flush_tlb_kernel_range_common(start, end);
551 }
552
flush_tlb_kernel_vm(void)553 void flush_tlb_kernel_vm(void)
554 {
555 flush_tlb_kernel_range_common(start_vm, end_vm);
556 }
557
__flush_tlb_one(unsigned long addr)558 void __flush_tlb_one(unsigned long addr)
559 {
560 flush_tlb_kernel_range_common(addr, addr + PAGE_SIZE);
561 }
562
fix_range(struct mm_struct * mm,unsigned long start_addr,unsigned long end_addr,int force)563 static void fix_range(struct mm_struct *mm, unsigned long start_addr,
564 unsigned long end_addr, int force)
565 {
566 /*
567 * Don't bother flushing if this address space is about to be
568 * destroyed.
569 */
570 if (atomic_read(&mm->mm_users) == 0)
571 return;
572
573 fix_range_common(mm, start_addr, end_addr, force);
574 }
575
flush_tlb_range(struct vm_area_struct * vma,unsigned long start,unsigned long end)576 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
577 unsigned long end)
578 {
579 if (vma->vm_mm == NULL)
580 flush_tlb_kernel_range_common(start, end);
581 else fix_range(vma->vm_mm, start, end, 0);
582 }
583 EXPORT_SYMBOL(flush_tlb_range);
584
flush_tlb_mm_range(struct mm_struct * mm,unsigned long start,unsigned long end)585 void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
586 unsigned long end)
587 {
588 fix_range(mm, start, end, 0);
589 }
590
flush_tlb_mm(struct mm_struct * mm)591 void flush_tlb_mm(struct mm_struct *mm)
592 {
593 struct vm_area_struct *vma = mm->mmap;
594
595 while (vma != NULL) {
596 fix_range(mm, vma->vm_start, vma->vm_end, 0);
597 vma = vma->vm_next;
598 }
599 }
600
force_flush_all(void)601 void force_flush_all(void)
602 {
603 struct mm_struct *mm = current->mm;
604 struct vm_area_struct *vma = mm->mmap;
605
606 while (vma != NULL) {
607 fix_range(mm, vma->vm_start, vma->vm_end, 1);
608 vma = vma->vm_next;
609 }
610 }
611
