xref: /openbmc/linux/arch/um/kernel/tlb.c (revision 12eb4683)
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.h>
9 #include <asm/pgtable.h>
10 #include <asm/tlbflush.h>
11 #include <as-layout.h>
12 #include <mem_user.h>
13 #include <os.h>
14 #include <skas.h>
15 
16 struct host_vm_change {
17 	struct host_vm_op {
18 		enum { NONE, MMAP, MUNMAP, MPROTECT } type;
19 		union {
20 			struct {
21 				unsigned long addr;
22 				unsigned long len;
23 				unsigned int prot;
24 				int fd;
25 				__u64 offset;
26 			} mmap;
27 			struct {
28 				unsigned long addr;
29 				unsigned long len;
30 			} munmap;
31 			struct {
32 				unsigned long addr;
33 				unsigned long len;
34 				unsigned int prot;
35 			} mprotect;
36 		} u;
37 	} ops[1];
38 	int index;
39 	struct mm_id *id;
40 	void *data;
41 	int force;
42 };
43 
44 #define INIT_HVC(mm, force) \
45 	((struct host_vm_change) \
46 	 { .ops		= { { .type = NONE } },	\
47 	   .id		= &mm->context.id, \
48        	   .data	= NULL, \
49 	   .index	= 0, \
50 	   .force	= force })
51 
52 static int do_ops(struct host_vm_change *hvc, int end,
53 		  int finished)
54 {
55 	struct host_vm_op *op;
56 	int i, ret = 0;
57 
58 	for (i = 0; i < end && !ret; i++) {
59 		op = &hvc->ops[i];
60 		switch (op->type) {
61 		case MMAP:
62 			ret = map(hvc->id, op->u.mmap.addr, op->u.mmap.len,
63 				  op->u.mmap.prot, op->u.mmap.fd,
64 				  op->u.mmap.offset, finished, &hvc->data);
65 			break;
66 		case MUNMAP:
67 			ret = unmap(hvc->id, op->u.munmap.addr,
68 				    op->u.munmap.len, finished, &hvc->data);
69 			break;
70 		case MPROTECT:
71 			ret = protect(hvc->id, op->u.mprotect.addr,
72 				      op->u.mprotect.len, op->u.mprotect.prot,
73 				      finished, &hvc->data);
74 			break;
75 		default:
76 			printk(KERN_ERR "Unknown op type %d in do_ops\n",
77 			       op->type);
78 			BUG();
79 			break;
80 		}
81 	}
82 
83 	return ret;
84 }
85 
86 static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
87 		    unsigned int prot, struct host_vm_change *hvc)
88 {
89 	__u64 offset;
90 	struct host_vm_op *last;
91 	int fd, ret = 0;
92 
93 	fd = phys_mapping(phys, &offset);
94 	if (hvc->index != 0) {
95 		last = &hvc->ops[hvc->index - 1];
96 		if ((last->type == MMAP) &&
97 		   (last->u.mmap.addr + last->u.mmap.len == virt) &&
98 		   (last->u.mmap.prot == prot) && (last->u.mmap.fd == fd) &&
99 		   (last->u.mmap.offset + last->u.mmap.len == offset)) {
100 			last->u.mmap.len += len;
101 			return 0;
102 		}
103 	}
104 
105 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
106 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
107 		hvc->index = 0;
108 	}
109 
110 	hvc->ops[hvc->index++] = ((struct host_vm_op)
111 				  { .type	= MMAP,
112 				    .u = { .mmap = { .addr	= virt,
113 						     .len	= len,
114 						     .prot	= prot,
115 						     .fd	= fd,
116 						     .offset	= offset }
117 			   } });
118 	return ret;
119 }
120 
121 static int add_munmap(unsigned long addr, unsigned long len,
122 		      struct host_vm_change *hvc)
123 {
124 	struct host_vm_op *last;
125 	int ret = 0;
126 
127 	if (hvc->index != 0) {
128 		last = &hvc->ops[hvc->index - 1];
129 		if ((last->type == MUNMAP) &&
130 		   (last->u.munmap.addr + last->u.mmap.len == addr)) {
131 			last->u.munmap.len += len;
132 			return 0;
133 		}
134 	}
135 
136 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
137 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
138 		hvc->index = 0;
139 	}
140 
141 	hvc->ops[hvc->index++] = ((struct host_vm_op)
142 				  { .type	= MUNMAP,
143 			     	    .u = { .munmap = { .addr	= addr,
144 						       .len	= len } } });
145 	return ret;
146 }
147 
148 static int add_mprotect(unsigned long addr, unsigned long len,
149 			unsigned int prot, struct host_vm_change *hvc)
150 {
151 	struct host_vm_op *last;
152 	int ret = 0;
153 
154 	if (hvc->index != 0) {
155 		last = &hvc->ops[hvc->index - 1];
156 		if ((last->type == MPROTECT) &&
157 		   (last->u.mprotect.addr + last->u.mprotect.len == addr) &&
158 		   (last->u.mprotect.prot == prot)) {
159 			last->u.mprotect.len += len;
160 			return 0;
161 		}
162 	}
163 
164 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
165 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
166 		hvc->index = 0;
167 	}
168 
169 	hvc->ops[hvc->index++] = ((struct host_vm_op)
170 				  { .type	= MPROTECT,
171 			     	    .u = { .mprotect = { .addr	= addr,
172 							 .len	= len,
173 							 .prot	= prot } } });
174 	return ret;
175 }
176 
177 #define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))
178 
179 static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
180 				   unsigned long end,
181 				   struct host_vm_change *hvc)
182 {
183 	pte_t *pte;
184 	int r, w, x, prot, ret = 0;
185 
186 	pte = pte_offset_kernel(pmd, addr);
187 	do {
188 		if ((addr >= STUB_START) && (addr < STUB_END))
189 			continue;
190 
191 		r = pte_read(*pte);
192 		w = pte_write(*pte);
193 		x = pte_exec(*pte);
194 		if (!pte_young(*pte)) {
195 			r = 0;
196 			w = 0;
197 		} else if (!pte_dirty(*pte))
198 			w = 0;
199 
200 		prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
201 			(x ? UM_PROT_EXEC : 0));
202 		if (hvc->force || pte_newpage(*pte)) {
203 			if (pte_present(*pte))
204 				ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
205 					       PAGE_SIZE, prot, hvc);
206 			else
207 				ret = add_munmap(addr, PAGE_SIZE, hvc);
208 		} else if (pte_newprot(*pte))
209 			ret = add_mprotect(addr, PAGE_SIZE, prot, hvc);
210 		*pte = pte_mkuptodate(*pte);
211 	} while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret));
212 	return ret;
213 }
214 
215 static inline int update_pmd_range(pud_t *pud, unsigned long addr,
216 				   unsigned long end,
217 				   struct host_vm_change *hvc)
218 {
219 	pmd_t *pmd;
220 	unsigned long next;
221 	int ret = 0;
222 
223 	pmd = pmd_offset(pud, addr);
224 	do {
225 		next = pmd_addr_end(addr, end);
226 		if (!pmd_present(*pmd)) {
227 			if (hvc->force || pmd_newpage(*pmd)) {
228 				ret = add_munmap(addr, next - addr, hvc);
229 				pmd_mkuptodate(*pmd);
230 			}
231 		}
232 		else ret = update_pte_range(pmd, addr, next, hvc);
233 	} while (pmd++, addr = next, ((addr < end) && !ret));
234 	return ret;
235 }
236 
237 static inline int update_pud_range(pgd_t *pgd, unsigned long addr,
238 				   unsigned long end,
239 				   struct host_vm_change *hvc)
240 {
241 	pud_t *pud;
242 	unsigned long next;
243 	int ret = 0;
244 
245 	pud = pud_offset(pgd, addr);
246 	do {
247 		next = pud_addr_end(addr, end);
248 		if (!pud_present(*pud)) {
249 			if (hvc->force || pud_newpage(*pud)) {
250 				ret = add_munmap(addr, next - addr, hvc);
251 				pud_mkuptodate(*pud);
252 			}
253 		}
254 		else ret = update_pmd_range(pud, addr, next, hvc);
255 	} while (pud++, addr = next, ((addr < end) && !ret));
256 	return ret;
257 }
258 
259 void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
260 		      unsigned long end_addr, int force)
261 {
262 	pgd_t *pgd;
263 	struct host_vm_change hvc;
264 	unsigned long addr = start_addr, next;
265 	int ret = 0;
266 
267 	hvc = INIT_HVC(mm, force);
268 	pgd = pgd_offset(mm, addr);
269 	do {
270 		next = pgd_addr_end(addr, end_addr);
271 		if (!pgd_present(*pgd)) {
272 			if (force || pgd_newpage(*pgd)) {
273 				ret = add_munmap(addr, next - addr, &hvc);
274 				pgd_mkuptodate(*pgd);
275 			}
276 		}
277 		else ret = update_pud_range(pgd, addr, next, &hvc);
278 	} while (pgd++, addr = next, ((addr < end_addr) && !ret));
279 
280 	if (!ret)
281 		ret = do_ops(&hvc, hvc.index, 1);
282 
283 	/* This is not an else because ret is modified above */
284 	if (ret) {
285 		printk(KERN_ERR "fix_range_common: failed, killing current "
286 		       "process\n");
287 		force_sig(SIGKILL, current);
288 	}
289 }
290 
291 static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
292 {
293 	struct mm_struct *mm;
294 	pgd_t *pgd;
295 	pud_t *pud;
296 	pmd_t *pmd;
297 	pte_t *pte;
298 	unsigned long addr, last;
299 	int updated = 0, err;
300 
301 	mm = &init_mm;
302 	for (addr = start; addr < end;) {
303 		pgd = pgd_offset(mm, addr);
304 		if (!pgd_present(*pgd)) {
305 			last = ADD_ROUND(addr, PGDIR_SIZE);
306 			if (last > end)
307 				last = end;
308 			if (pgd_newpage(*pgd)) {
309 				updated = 1;
310 				err = os_unmap_memory((void *) addr,
311 						      last - addr);
312 				if (err < 0)
313 					panic("munmap failed, errno = %d\n",
314 					      -err);
315 			}
316 			addr = last;
317 			continue;
318 		}
319 
320 		pud = pud_offset(pgd, addr);
321 		if (!pud_present(*pud)) {
322 			last = ADD_ROUND(addr, PUD_SIZE);
323 			if (last > end)
324 				last = end;
325 			if (pud_newpage(*pud)) {
326 				updated = 1;
327 				err = os_unmap_memory((void *) addr,
328 						      last - addr);
329 				if (err < 0)
330 					panic("munmap failed, errno = %d\n",
331 					      -err);
332 			}
333 			addr = last;
334 			continue;
335 		}
336 
337 		pmd = pmd_offset(pud, addr);
338 		if (!pmd_present(*pmd)) {
339 			last = ADD_ROUND(addr, PMD_SIZE);
340 			if (last > end)
341 				last = end;
342 			if (pmd_newpage(*pmd)) {
343 				updated = 1;
344 				err = os_unmap_memory((void *) addr,
345 						      last - addr);
346 				if (err < 0)
347 					panic("munmap failed, errno = %d\n",
348 					      -err);
349 			}
350 			addr = last;
351 			continue;
352 		}
353 
354 		pte = pte_offset_kernel(pmd, addr);
355 		if (!pte_present(*pte) || pte_newpage(*pte)) {
356 			updated = 1;
357 			err = os_unmap_memory((void *) addr,
358 					      PAGE_SIZE);
359 			if (err < 0)
360 				panic("munmap failed, errno = %d\n",
361 				      -err);
362 			if (pte_present(*pte))
363 				map_memory(addr,
364 					   pte_val(*pte) & PAGE_MASK,
365 					   PAGE_SIZE, 1, 1, 1);
366 		}
367 		else if (pte_newprot(*pte)) {
368 			updated = 1;
369 			os_protect_memory((void *) addr, PAGE_SIZE, 1, 1, 1);
370 		}
371 		addr += PAGE_SIZE;
372 	}
373 	return updated;
374 }
375 
376 void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
377 {
378 	pgd_t *pgd;
379 	pud_t *pud;
380 	pmd_t *pmd;
381 	pte_t *pte;
382 	struct mm_struct *mm = vma->vm_mm;
383 	void *flush = NULL;
384 	int r, w, x, prot, err = 0;
385 	struct mm_id *mm_id;
386 
387 	address &= PAGE_MASK;
388 	pgd = pgd_offset(mm, address);
389 	if (!pgd_present(*pgd))
390 		goto kill;
391 
392 	pud = pud_offset(pgd, address);
393 	if (!pud_present(*pud))
394 		goto kill;
395 
396 	pmd = pmd_offset(pud, address);
397 	if (!pmd_present(*pmd))
398 		goto kill;
399 
400 	pte = pte_offset_kernel(pmd, address);
401 
402 	r = pte_read(*pte);
403 	w = pte_write(*pte);
404 	x = pte_exec(*pte);
405 	if (!pte_young(*pte)) {
406 		r = 0;
407 		w = 0;
408 	} else if (!pte_dirty(*pte)) {
409 		w = 0;
410 	}
411 
412 	mm_id = &mm->context.id;
413 	prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
414 		(x ? UM_PROT_EXEC : 0));
415 	if (pte_newpage(*pte)) {
416 		if (pte_present(*pte)) {
417 			unsigned long long offset;
418 			int fd;
419 
420 			fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
421 			err = map(mm_id, address, PAGE_SIZE, prot, fd, offset,
422 				  1, &flush);
423 		}
424 		else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
425 	}
426 	else if (pte_newprot(*pte))
427 		err = protect(mm_id, address, PAGE_SIZE, prot, 1, &flush);
428 
429 	if (err)
430 		goto kill;
431 
432 	*pte = pte_mkuptodate(*pte);
433 
434 	return;
435 
436 kill:
437 	printk(KERN_ERR "Failed to flush page for address 0x%lx\n", address);
438 	force_sig(SIGKILL, current);
439 }
440 
441 pgd_t *pgd_offset_proc(struct mm_struct *mm, unsigned long address)
442 {
443 	return pgd_offset(mm, address);
444 }
445 
446 pud_t *pud_offset_proc(pgd_t *pgd, unsigned long address)
447 {
448 	return pud_offset(pgd, address);
449 }
450 
451 pmd_t *pmd_offset_proc(pud_t *pud, unsigned long address)
452 {
453 	return pmd_offset(pud, address);
454 }
455 
456 pte_t *pte_offset_proc(pmd_t *pmd, unsigned long address)
457 {
458 	return pte_offset_kernel(pmd, address);
459 }
460 
461 pte_t *addr_pte(struct task_struct *task, unsigned long addr)
462 {
463 	pgd_t *pgd = pgd_offset(task->mm, addr);
464 	pud_t *pud = pud_offset(pgd, addr);
465 	pmd_t *pmd = pmd_offset(pud, addr);
466 
467 	return pte_offset_map(pmd, addr);
468 }
469 
470 void flush_tlb_all(void)
471 {
472 	flush_tlb_mm(current->mm);
473 }
474 
475 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
476 {
477 	flush_tlb_kernel_range_common(start, end);
478 }
479 
480 void flush_tlb_kernel_vm(void)
481 {
482 	flush_tlb_kernel_range_common(start_vm, end_vm);
483 }
484 
485 void __flush_tlb_one(unsigned long addr)
486 {
487 	flush_tlb_kernel_range_common(addr, addr + PAGE_SIZE);
488 }
489 
490 static void fix_range(struct mm_struct *mm, unsigned long start_addr,
491 		      unsigned long end_addr, int force)
492 {
493 	fix_range_common(mm, start_addr, end_addr, force);
494 }
495 
496 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
497 		     unsigned long end)
498 {
499 	if (vma->vm_mm == NULL)
500 		flush_tlb_kernel_range_common(start, end);
501 	else fix_range(vma->vm_mm, start, end, 0);
502 }
503 EXPORT_SYMBOL(flush_tlb_range);
504 
505 void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
506 			unsigned long end)
507 {
508 	/*
509 	 * Don't bother flushing if this address space is about to be
510 	 * destroyed.
511 	 */
512 	if (atomic_read(&mm->mm_users) == 0)
513 		return;
514 
515 	fix_range(mm, start, end, 0);
516 }
517 
518 void flush_tlb_mm(struct mm_struct *mm)
519 {
520 	struct vm_area_struct *vma = mm->mmap;
521 
522 	while (vma != NULL) {
523 		fix_range(mm, vma->vm_start, vma->vm_end, 0);
524 		vma = vma->vm_next;
525 	}
526 }
527 
528 void force_flush_all(void)
529 {
530 	struct mm_struct *mm = current->mm;
531 	struct vm_area_struct *vma = mm->mmap;
532 
533 	while (vma != NULL) {
534 		fix_range(mm, vma->vm_start, vma->vm_end, 1);
535 		vma = vma->vm_next;
536 	}
537 }
538