xref: /openbmc/linux/arch/um/kernel/tlb.c (revision b593bce5) 
1 /*
2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5 
6 #include <linux/mm.h>
7 #include <linux/module.h>
8 #include <linux/sched/signal.h>
9 
10 #include <asm/pgtable.h>
11 #include <asm/tlbflush.h>
12 #include <as-layout.h>
13 #include <mem_user.h>
14 #include <os.h>
15 #include <skas.h>
16 #include <kern_util.h>
17 
18 struct host_vm_change {
19 	struct host_vm_op {
20 		enum { NONE, MMAP, MUNMAP, MPROTECT } type;
21 		union {
22 			struct {
23 				unsigned long addr;
24 				unsigned long len;
25 				unsigned int prot;
26 				int fd;
27 				__u64 offset;
28 			} mmap;
29 			struct {
30 				unsigned long addr;
31 				unsigned long len;
32 			} munmap;
33 			struct {
34 				unsigned long addr;
35 				unsigned long len;
36 				unsigned int prot;
37 			} mprotect;
38 		} u;
39 	} ops[1];
40 	int userspace;
41 	int index;
42 	struct mm_struct *mm;
43 	void *data;
44 	int force;
45 };
46 
47 #define INIT_HVC(mm, force, userspace) \
48 	((struct host_vm_change) \
49 	 { .ops		= { { .type = NONE } },	\
50 	   .mm		= mm, \
51        	   .data	= NULL, \
52 	   .userspace	= userspace, \
53 	   .index	= 0, \
54 	   .force	= force })
55 
56 static void report_enomem(void)
57 {
58 	printk(KERN_ERR "UML ran out of memory on the host side! "
59 			"This can happen due to a memory limitation or "
60 			"vm.max_map_count has been reached.\n");
61 }
62 
63 static int do_ops(struct host_vm_change *hvc, int end,
64 		  int finished)
65 {
66 	struct host_vm_op *op;
67 	int i, ret = 0;
68 
69 	for (i = 0; i < end && !ret; i++) {
70 		op = &hvc->ops[i];
71 		switch (op->type) {
72 		case MMAP:
73 			if (hvc->userspace)
74 				ret = map(&hvc->mm->context.id, op->u.mmap.addr,
75 					  op->u.mmap.len, op->u.mmap.prot,
76 					  op->u.mmap.fd,
77 					  op->u.mmap.offset, finished,
78 					  &hvc->data);
79 			else
80 				map_memory(op->u.mmap.addr, op->u.mmap.offset,
81 					   op->u.mmap.len, 1, 1, 1);
82 			break;
83 		case MUNMAP:
84 			if (hvc->userspace)
85 				ret = unmap(&hvc->mm->context.id,
86 					    op->u.munmap.addr,
87 					    op->u.munmap.len, finished,
88 					    &hvc->data);
89 			else
90 				ret = os_unmap_memory(
91 					(void *) op->u.munmap.addr,
92 						      op->u.munmap.len);
93 
94 			break;
95 		case MPROTECT:
96 			if (hvc->userspace)
97 				ret = protect(&hvc->mm->context.id,
98 					      op->u.mprotect.addr,
99 					      op->u.mprotect.len,
100 					      op->u.mprotect.prot,
101 					      finished, &hvc->data);
102 			else
103 				ret = os_protect_memory(
104 					(void *) op->u.mprotect.addr,
105 							op->u.mprotect.len,
106 							1, 1, 1);
107 			break;
108 		default:
109 			printk(KERN_ERR "Unknown op type %d in do_ops\n",
110 			       op->type);
111 			BUG();
112 			break;
113 		}
114 	}
115 
116 	if (ret == -ENOMEM)
117 		report_enomem();
118 
119 	return ret;
120 }
121 
122 static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
123 		    unsigned int prot, struct host_vm_change *hvc)
124 {
125 	__u64 offset;
126 	struct host_vm_op *last;
127 	int fd = -1, ret = 0;
128 
129 	if (hvc->userspace)
130 		fd = phys_mapping(phys, &offset);
131 	else
132 		offset = phys;
133 	if (hvc->index != 0) {
134 		last = &hvc->ops[hvc->index - 1];
135 		if ((last->type == MMAP) &&
136 		   (last->u.mmap.addr + last->u.mmap.len == virt) &&
137 		   (last->u.mmap.prot == prot) && (last->u.mmap.fd == fd) &&
138 		   (last->u.mmap.offset + last->u.mmap.len == offset)) {
139 			last->u.mmap.len += len;
140 			return 0;
141 		}
142 	}
143 
144 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
145 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
146 		hvc->index = 0;
147 	}
148 
149 	hvc->ops[hvc->index++] = ((struct host_vm_op)
150 				  { .type	= MMAP,
151 				    .u = { .mmap = { .addr	= virt,
152 						     .len	= len,
153 						     .prot	= prot,
154 						     .fd	= fd,
155 						     .offset	= offset }
156 			   } });
157 	return ret;
158 }
159 
160 static int add_munmap(unsigned long addr, unsigned long len,
161 		      struct host_vm_change *hvc)
162 {
163 	struct host_vm_op *last;
164 	int ret = 0;
165 
166 	if ((addr >= STUB_START) && (addr < STUB_END))
167 		return -EINVAL;
168 
169 	if (hvc->index != 0) {
170 		last = &hvc->ops[hvc->index - 1];
171 		if ((last->type == MUNMAP) &&
172 		   (last->u.munmap.addr + last->u.mmap.len == addr)) {
173 			last->u.munmap.len += len;
174 			return 0;
175 		}
176 	}
177 
178 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
179 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
180 		hvc->index = 0;
181 	}
182 
183 	hvc->ops[hvc->index++] = ((struct host_vm_op)
184 				  { .type	= MUNMAP,
185 			     	    .u = { .munmap = { .addr	= addr,
186 						       .len	= len } } });
187 	return ret;
188 }
189 
190 static int add_mprotect(unsigned long addr, unsigned long len,
191 			unsigned int prot, struct host_vm_change *hvc)
192 {
193 	struct host_vm_op *last;
194 	int ret = 0;
195 
196 	if (hvc->index != 0) {
197 		last = &hvc->ops[hvc->index - 1];
198 		if ((last->type == MPROTECT) &&
199 		   (last->u.mprotect.addr + last->u.mprotect.len == addr) &&
200 		   (last->u.mprotect.prot == prot)) {
201 			last->u.mprotect.len += len;
202 			return 0;
203 		}
204 	}
205 
206 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
207 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
208 		hvc->index = 0;
209 	}
210 
211 	hvc->ops[hvc->index++] = ((struct host_vm_op)
212 				  { .type	= MPROTECT,
213 			     	    .u = { .mprotect = { .addr	= addr,
214 							 .len	= len,
215 							 .prot	= prot } } });
216 	return ret;
217 }
218 
219 #define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))
220 
221 static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
222 				   unsigned long end,
223 				   struct host_vm_change *hvc)
224 {
225 	pte_t *pte;
226 	int r, w, x, prot, ret = 0;
227 
228 	pte = pte_offset_kernel(pmd, addr);
229 	do {
230 		if ((addr >= STUB_START) && (addr < STUB_END))
231 			continue;
232 
233 		r = pte_read(*pte);
234 		w = pte_write(*pte);
235 		x = pte_exec(*pte);
236 		if (!pte_young(*pte)) {
237 			r = 0;
238 			w = 0;
239 		} else if (!pte_dirty(*pte))
240 			w = 0;
241 
242 		prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
243 			(x ? UM_PROT_EXEC : 0));
244 		if (hvc->force || pte_newpage(*pte)) {
245 			if (pte_present(*pte)) {
246 				if (pte_newpage(*pte))
247 					ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
248 						       PAGE_SIZE, prot, hvc);
249 			} else
250 				ret = add_munmap(addr, PAGE_SIZE, hvc);
251 		} else if (pte_newprot(*pte))
252 			ret = add_mprotect(addr, PAGE_SIZE, prot, hvc);
253 		*pte = pte_mkuptodate(*pte);
254 	} while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret));
255 	return ret;
256 }
257 
258 static inline int update_pmd_range(pud_t *pud, unsigned long addr,
259 				   unsigned long end,
260 				   struct host_vm_change *hvc)
261 {
262 	pmd_t *pmd;
263 	unsigned long next;
264 	int ret = 0;
265 
266 	pmd = pmd_offset(pud, addr);
267 	do {
268 		next = pmd_addr_end(addr, end);
269 		if (!pmd_present(*pmd)) {
270 			if (hvc->force || pmd_newpage(*pmd)) {
271 				ret = add_munmap(addr, next - addr, hvc);
272 				pmd_mkuptodate(*pmd);
273 			}
274 		}
275 		else ret = update_pte_range(pmd, addr, next, hvc);
276 	} while (pmd++, addr = next, ((addr < end) && !ret));
277 	return ret;
278 }
279 
280 static inline int update_pud_range(pgd_t *pgd, unsigned long addr,
281 				   unsigned long end,
282 				   struct host_vm_change *hvc)
283 {
284 	pud_t *pud;
285 	unsigned long next;
286 	int ret = 0;
287 
288 	pud = pud_offset(pgd, addr);
289 	do {
290 		next = pud_addr_end(addr, end);
291 		if (!pud_present(*pud)) {
292 			if (hvc->force || pud_newpage(*pud)) {
293 				ret = add_munmap(addr, next - addr, hvc);
294 				pud_mkuptodate(*pud);
295 			}
296 		}
297 		else ret = update_pmd_range(pud, addr, next, hvc);
298 	} while (pud++, addr = next, ((addr < end) && !ret));
299 	return ret;
300 }
301 
302 void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
303 		      unsigned long end_addr, int force)
304 {
305 	pgd_t *pgd;
306 	struct host_vm_change hvc;
307 	unsigned long addr = start_addr, next;
308 	int ret = 0, userspace = 1;
309 
310 	hvc = INIT_HVC(mm, force, userspace);
311 	pgd = pgd_offset(mm, addr);
312 	do {
313 		next = pgd_addr_end(addr, end_addr);
314 		if (!pgd_present(*pgd)) {
315 			if (force || pgd_newpage(*pgd)) {
316 				ret = add_munmap(addr, next - addr, &hvc);
317 				pgd_mkuptodate(*pgd);
318 			}
319 		}
320 		else ret = update_pud_range(pgd, addr, next, &hvc);
321 	} while (pgd++, addr = next, ((addr < end_addr) && !ret));
322 
323 	if (!ret)
324 		ret = do_ops(&hvc, hvc.index, 1);
325 
326 	/* This is not an else because ret is modified above */
327 	if (ret) {
328 		printk(KERN_ERR "fix_range_common: failed, killing current "
329 		       "process: %d\n", task_tgid_vnr(current));
330 		/* We are under mmap_sem, release it such that current can terminate */
331 		up_write(&current->mm->mmap_sem);
332 		force_sig(SIGKILL);
333 		do_signal(&current->thread.regs);
334 	}
335 }
336 
337 static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
338 {
339 	struct mm_struct *mm;
340 	pgd_t *pgd;
341 	pud_t *pud;
342 	pmd_t *pmd;
343 	pte_t *pte;
344 	unsigned long addr, last;
345 	int updated = 0, err = 0, force = 0, userspace = 0;
346 	struct host_vm_change hvc;
347 
348 	mm = &init_mm;
349 	hvc = INIT_HVC(mm, force, userspace);
350 	for (addr = start; addr < end;) {
351 		pgd = pgd_offset(mm, addr);
352 		if (!pgd_present(*pgd)) {
353 			last = ADD_ROUND(addr, PGDIR_SIZE);
354 			if (last > end)
355 				last = end;
356 			if (pgd_newpage(*pgd)) {
357 				updated = 1;
358 				err = add_munmap(addr, last - addr, &hvc);
359 				if (err < 0)
360 					panic("munmap failed, errno = %d\n",
361 					      -err);
362 			}
363 			addr = last;
364 			continue;
365 		}
366 
367 		pud = pud_offset(pgd, addr);
368 		if (!pud_present(*pud)) {
369 			last = ADD_ROUND(addr, PUD_SIZE);
370 			if (last > end)
371 				last = end;
372 			if (pud_newpage(*pud)) {
373 				updated = 1;
374 				err = add_munmap(addr, last - addr, &hvc);
375 				if (err < 0)
376 					panic("munmap failed, errno = %d\n",
377 					      -err);
378 			}
379 			addr = last;
380 			continue;
381 		}
382 
383 		pmd = pmd_offset(pud, addr);
384 		if (!pmd_present(*pmd)) {
385 			last = ADD_ROUND(addr, PMD_SIZE);
386 			if (last > end)
387 				last = end;
388 			if (pmd_newpage(*pmd)) {
389 				updated = 1;
390 				err = add_munmap(addr, last - addr, &hvc);
391 				if (err < 0)
392 					panic("munmap failed, errno = %d\n",
393 					      -err);
394 			}
395 			addr = last;
396 			continue;
397 		}
398 
399 		pte = pte_offset_kernel(pmd, addr);
400 		if (!pte_present(*pte) || pte_newpage(*pte)) {
401 			updated = 1;
402 			err = add_munmap(addr, PAGE_SIZE, &hvc);
403 			if (err < 0)
404 				panic("munmap failed, errno = %d\n",
405 				      -err);
406 			if (pte_present(*pte))
407 				err = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
408 					       PAGE_SIZE, 0, &hvc);
409 		}
410 		else if (pte_newprot(*pte)) {
411 			updated = 1;
412 			err = add_mprotect(addr, PAGE_SIZE, 0, &hvc);
413 		}
414 		addr += PAGE_SIZE;
415 	}
416 	if (!err)
417 		err = do_ops(&hvc, hvc.index, 1);
418 
419 	if (err < 0)
420 		panic("flush_tlb_kernel failed, errno = %d\n", err);
421 	return updated;
422 }
423 
424 void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
425 {
426 	pgd_t *pgd;
427 	pud_t *pud;
428 	pmd_t *pmd;
429 	pte_t *pte;
430 	struct mm_struct *mm = vma->vm_mm;
431 	void *flush = NULL;
432 	int r, w, x, prot, err = 0;
433 	struct mm_id *mm_id;
434 
435 	address &= PAGE_MASK;
436 	pgd = pgd_offset(mm, address);
437 	if (!pgd_present(*pgd))
438 		goto kill;
439 
440 	pud = pud_offset(pgd, address);
441 	if (!pud_present(*pud))
442 		goto kill;
443 
444 	pmd = pmd_offset(pud, address);
445 	if (!pmd_present(*pmd))
446 		goto kill;
447 
448 	pte = pte_offset_kernel(pmd, address);
449 
450 	r = pte_read(*pte);
451 	w = pte_write(*pte);
452 	x = pte_exec(*pte);
453 	if (!pte_young(*pte)) {
454 		r = 0;
455 		w = 0;
456 	} else if (!pte_dirty(*pte)) {
457 		w = 0;
458 	}
459 
460 	mm_id = &mm->context.id;
461 	prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
462 		(x ? UM_PROT_EXEC : 0));
463 	if (pte_newpage(*pte)) {
464 		if (pte_present(*pte)) {
465 			unsigned long long offset;
466 			int fd;
467 
468 			fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
469 			err = map(mm_id, address, PAGE_SIZE, prot, fd, offset,
470 				  1, &flush);
471 		}
472 		else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
473 	}
474 	else if (pte_newprot(*pte))
475 		err = protect(mm_id, address, PAGE_SIZE, prot, 1, &flush);
476 
477 	if (err) {
478 		if (err == -ENOMEM)
479 			report_enomem();
480 
481 		goto kill;
482 	}
483 
484 	*pte = pte_mkuptodate(*pte);
485 
486 	return;
487 
488 kill:
489 	printk(KERN_ERR "Failed to flush page for address 0x%lx\n", address);
490 	force_sig(SIGKILL);
491 }
492 
493 pgd_t *pgd_offset_proc(struct mm_struct *mm, unsigned long address)
494 {
495 	return pgd_offset(mm, address);
496 }
497 
498 pud_t *pud_offset_proc(pgd_t *pgd, unsigned long address)
499 {
500 	return pud_offset(pgd, address);
501 }
502 
503 pmd_t *pmd_offset_proc(pud_t *pud, unsigned long address)
504 {
505 	return pmd_offset(pud, address);
506 }
507 
508 pte_t *pte_offset_proc(pmd_t *pmd, unsigned long address)
509 {
510 	return pte_offset_kernel(pmd, address);
511 }
512 
513 pte_t *addr_pte(struct task_struct *task, unsigned long addr)
514 {
515 	pgd_t *pgd = pgd_offset(task->mm, addr);
516 	pud_t *pud = pud_offset(pgd, addr);
517 	pmd_t *pmd = pmd_offset(pud, addr);
518 
519 	return pte_offset_map(pmd, addr);
520 }
521 
522 void flush_tlb_all(void)
523 {
524 	/*
525 	 * Don't bother flushing if this address space is about to be
526 	 * destroyed.
527 	 */
528 	if (atomic_read(&current->mm->mm_users) == 0)
529 		return;
530 
531 	flush_tlb_mm(current->mm);
532 }
533 
534 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
535 {
536 	flush_tlb_kernel_range_common(start, end);
537 }
538 
539 void flush_tlb_kernel_vm(void)
540 {
541 	flush_tlb_kernel_range_common(start_vm, end_vm);
542 }
543 
544 void __flush_tlb_one(unsigned long addr)
545 {
546 	flush_tlb_kernel_range_common(addr, addr + PAGE_SIZE);
547 }
548 
549 static void fix_range(struct mm_struct *mm, unsigned long start_addr,
550 		      unsigned long end_addr, int force)
551 {
552 	/*
553 	 * Don't bother flushing if this address space is about to be
554 	 * destroyed.
555 	 */
556 	if (atomic_read(&mm->mm_users) == 0)
557 		return;
558 
559 	fix_range_common(mm, start_addr, end_addr, force);
560 }
561 
562 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
563 		     unsigned long end)
564 {
565 	if (vma->vm_mm == NULL)
566 		flush_tlb_kernel_range_common(start, end);
567 	else fix_range(vma->vm_mm, start, end, 0);
568 }
569 EXPORT_SYMBOL(flush_tlb_range);
570 
571 void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
572 			unsigned long end)
573 {
574 	fix_range(mm, start, end, 0);
575 }
576 
577 void flush_tlb_mm(struct mm_struct *mm)
578 {
579 	struct vm_area_struct *vma = mm->mmap;
580 
581 	while (vma != NULL) {
582 		fix_range(mm, vma->vm_start, vma->vm_end, 0);
583 		vma = vma->vm_next;
584 	}
585 }
586 
587 void force_flush_all(void)
588 {
589 	struct mm_struct *mm = current->mm;
590 	struct vm_area_struct *vma = mm->mmap;
591 
592 	while (vma != NULL) {
593 		fix_range(mm, vma->vm_start, vma->vm_end, 1);
594 		vma = vma->vm_next;
595 	}
596 }
597