xref: /openbmc/linux/arch/um/kernel/tlb.c (revision e1a3e724) 
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 #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 index;
40 	struct mm_id *id;
41 	void *data;
42 	int force;
43 };
44 
45 #define INIT_HVC(mm, force) \
46 	((struct host_vm_change) \
47 	 { .ops		= { { .type = NONE } },	\
48 	   .id		= &mm->context.id, \
49        	   .data	= NULL, \
50 	   .index	= 0, \
51 	   .force	= force })
52 
53 static int do_ops(struct host_vm_change *hvc, int end,
54 		  int finished)
55 {
56 	struct host_vm_op *op;
57 	int i, ret = 0;
58 
59 	for (i = 0; i < end && !ret; i++) {
60 		op = &hvc->ops[i];
61 		switch (op->type) {
62 		case MMAP:
63 			ret = map(hvc->id, op->u.mmap.addr, op->u.mmap.len,
64 				  op->u.mmap.prot, op->u.mmap.fd,
65 				  op->u.mmap.offset, finished, &hvc->data);
66 			break;
67 		case MUNMAP:
68 			ret = unmap(hvc->id, op->u.munmap.addr,
69 				    op->u.munmap.len, finished, &hvc->data);
70 			break;
71 		case MPROTECT:
72 			ret = protect(hvc->id, op->u.mprotect.addr,
73 				      op->u.mprotect.len, op->u.mprotect.prot,
74 				      finished, &hvc->data);
75 			break;
76 		default:
77 			printk(KERN_ERR "Unknown op type %d in do_ops\n",
78 			       op->type);
79 			BUG();
80 			break;
81 		}
82 	}
83 
84 	return ret;
85 }
86 
87 static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
88 		    unsigned int prot, struct host_vm_change *hvc)
89 {
90 	__u64 offset;
91 	struct host_vm_op *last;
92 	int fd, ret = 0;
93 
94 	fd = phys_mapping(phys, &offset);
95 	if (hvc->index != 0) {
96 		last = &hvc->ops[hvc->index - 1];
97 		if ((last->type == MMAP) &&
98 		   (last->u.mmap.addr + last->u.mmap.len == virt) &&
99 		   (last->u.mmap.prot == prot) && (last->u.mmap.fd == fd) &&
100 		   (last->u.mmap.offset + last->u.mmap.len == offset)) {
101 			last->u.mmap.len += len;
102 			return 0;
103 		}
104 	}
105 
106 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
107 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
108 		hvc->index = 0;
109 	}
110 
111 	hvc->ops[hvc->index++] = ((struct host_vm_op)
112 				  { .type	= MMAP,
113 				    .u = { .mmap = { .addr	= virt,
114 						     .len	= len,
115 						     .prot	= prot,
116 						     .fd	= fd,
117 						     .offset	= offset }
118 			   } });
119 	return ret;
120 }
121 
122 static int add_munmap(unsigned long addr, unsigned long len,
123 		      struct host_vm_change *hvc)
124 {
125 	struct host_vm_op *last;
126 	int ret = 0;
127 
128 	if ((addr >= STUB_START) && (addr < STUB_END))
129 		return -EINVAL;
130 
131 	if (hvc->index != 0) {
132 		last = &hvc->ops[hvc->index - 1];
133 		if ((last->type == MUNMAP) &&
134 		   (last->u.munmap.addr + last->u.mmap.len == addr)) {
135 			last->u.munmap.len += len;
136 			return 0;
137 		}
138 	}
139 
140 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
141 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
142 		hvc->index = 0;
143 	}
144 
145 	hvc->ops[hvc->index++] = ((struct host_vm_op)
146 				  { .type	= MUNMAP,
147 			     	    .u = { .munmap = { .addr	= addr,
148 						       .len	= len } } });
149 	return ret;
150 }
151 
152 static int add_mprotect(unsigned long addr, unsigned long len,
153 			unsigned int prot, struct host_vm_change *hvc)
154 {
155 	struct host_vm_op *last;
156 	int ret = 0;
157 
158 	if (hvc->index != 0) {
159 		last = &hvc->ops[hvc->index - 1];
160 		if ((last->type == MPROTECT) &&
161 		   (last->u.mprotect.addr + last->u.mprotect.len == addr) &&
162 		   (last->u.mprotect.prot == prot)) {
163 			last->u.mprotect.len += len;
164 			return 0;
165 		}
166 	}
167 
168 	if (hvc->index == ARRAY_SIZE(hvc->ops)) {
169 		ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
170 		hvc->index = 0;
171 	}
172 
173 	hvc->ops[hvc->index++] = ((struct host_vm_op)
174 				  { .type	= MPROTECT,
175 			     	    .u = { .mprotect = { .addr	= addr,
176 							 .len	= len,
177 							 .prot	= prot } } });
178 	return ret;
179 }
180 
181 #define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))
182 
183 static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
184 				   unsigned long end,
185 				   struct host_vm_change *hvc)
186 {
187 	pte_t *pte;
188 	int r, w, x, prot, ret = 0;
189 
190 	pte = pte_offset_kernel(pmd, addr);
191 	do {
192 		if ((addr >= STUB_START) && (addr < STUB_END))
193 			continue;
194 
195 		r = pte_read(*pte);
196 		w = pte_write(*pte);
197 		x = pte_exec(*pte);
198 		if (!pte_young(*pte)) {
199 			r = 0;
200 			w = 0;
201 		} else if (!pte_dirty(*pte))
202 			w = 0;
203 
204 		prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
205 			(x ? UM_PROT_EXEC : 0));
206 		if (hvc->force || pte_newpage(*pte)) {
207 			if (pte_present(*pte))
208 				ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
209 					       PAGE_SIZE, prot, hvc);
210 			else
211 				ret = add_munmap(addr, PAGE_SIZE, hvc);
212 		} else if (pte_newprot(*pte))
213 			ret = add_mprotect(addr, PAGE_SIZE, prot, hvc);
214 		*pte = pte_mkuptodate(*pte);
215 	} while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret));
216 	return ret;
217 }
218 
219 static inline int update_pmd_range(pud_t *pud, unsigned long addr,
220 				   unsigned long end,
221 				   struct host_vm_change *hvc)
222 {
223 	pmd_t *pmd;
224 	unsigned long next;
225 	int ret = 0;
226 
227 	pmd = pmd_offset(pud, addr);
228 	do {
229 		next = pmd_addr_end(addr, end);
230 		if (!pmd_present(*pmd)) {
231 			if (hvc->force || pmd_newpage(*pmd)) {
232 				ret = add_munmap(addr, next - addr, hvc);
233 				pmd_mkuptodate(*pmd);
234 			}
235 		}
236 		else ret = update_pte_range(pmd, addr, next, hvc);
237 	} while (pmd++, addr = next, ((addr < end) && !ret));
238 	return ret;
239 }
240 
241 static inline int update_pud_range(pgd_t *pgd, unsigned long addr,
242 				   unsigned long end,
243 				   struct host_vm_change *hvc)
244 {
245 	pud_t *pud;
246 	unsigned long next;
247 	int ret = 0;
248 
249 	pud = pud_offset(pgd, addr);
250 	do {
251 		next = pud_addr_end(addr, end);
252 		if (!pud_present(*pud)) {
253 			if (hvc->force || pud_newpage(*pud)) {
254 				ret = add_munmap(addr, next - addr, hvc);
255 				pud_mkuptodate(*pud);
256 			}
257 		}
258 		else ret = update_pmd_range(pud, addr, next, hvc);
259 	} while (pud++, addr = next, ((addr < end) && !ret));
260 	return ret;
261 }
262 
263 void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
264 		      unsigned long end_addr, int force)
265 {
266 	pgd_t *pgd;
267 	struct host_vm_change hvc;
268 	unsigned long addr = start_addr, next;
269 	int ret = 0;
270 
271 	hvc = INIT_HVC(mm, force);
272 	pgd = pgd_offset(mm, addr);
273 	do {
274 		next = pgd_addr_end(addr, end_addr);
275 		if (!pgd_present(*pgd)) {
276 			if (force || pgd_newpage(*pgd)) {
277 				ret = add_munmap(addr, next - addr, &hvc);
278 				pgd_mkuptodate(*pgd);
279 			}
280 		}
281 		else ret = update_pud_range(pgd, addr, next, &hvc);
282 	} while (pgd++, addr = next, ((addr < end_addr) && !ret));
283 
284 	if (!ret)
285 		ret = do_ops(&hvc, hvc.index, 1);
286 
287 	/* This is not an else because ret is modified above */
288 	if (ret) {
289 		printk(KERN_ERR "fix_range_common: failed, killing current "
290 		       "process: %d\n", task_tgid_vnr(current));
291 		/* We are under mmap_sem, release it such that current can terminate */
292 		up_write(&current->mm->mmap_sem);
293 		force_sig(SIGKILL, current);
294 		do_signal(&current->thread.regs);
295 	}
296 }
297 
298 static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
299 {
300 	struct mm_struct *mm;
301 	pgd_t *pgd;
302 	pud_t *pud;
303 	pmd_t *pmd;
304 	pte_t *pte;
305 	unsigned long addr, last;
306 	int updated = 0, err;
307 
308 	mm = &init_mm;
309 	for (addr = start; addr < end;) {
310 		pgd = pgd_offset(mm, addr);
311 		if (!pgd_present(*pgd)) {
312 			last = ADD_ROUND(addr, PGDIR_SIZE);
313 			if (last > end)
314 				last = end;
315 			if (pgd_newpage(*pgd)) {
316 				updated = 1;
317 				err = os_unmap_memory((void *) addr,
318 						      last - addr);
319 				if (err < 0)
320 					panic("munmap failed, errno = %d\n",
321 					      -err);
322 			}
323 			addr = last;
324 			continue;
325 		}
326 
327 		pud = pud_offset(pgd, addr);
328 		if (!pud_present(*pud)) {
329 			last = ADD_ROUND(addr, PUD_SIZE);
330 			if (last > end)
331 				last = end;
332 			if (pud_newpage(*pud)) {
333 				updated = 1;
334 				err = os_unmap_memory((void *) addr,
335 						      last - addr);
336 				if (err < 0)
337 					panic("munmap failed, errno = %d\n",
338 					      -err);
339 			}
340 			addr = last;
341 			continue;
342 		}
343 
344 		pmd = pmd_offset(pud, addr);
345 		if (!pmd_present(*pmd)) {
346 			last = ADD_ROUND(addr, PMD_SIZE);
347 			if (last > end)
348 				last = end;
349 			if (pmd_newpage(*pmd)) {
350 				updated = 1;
351 				err = os_unmap_memory((void *) addr,
352 						      last - addr);
353 				if (err < 0)
354 					panic("munmap failed, errno = %d\n",
355 					      -err);
356 			}
357 			addr = last;
358 			continue;
359 		}
360 
361 		pte = pte_offset_kernel(pmd, addr);
362 		if (!pte_present(*pte) || pte_newpage(*pte)) {
363 			updated = 1;
364 			err = os_unmap_memory((void *) addr,
365 					      PAGE_SIZE);
366 			if (err < 0)
367 				panic("munmap failed, errno = %d\n",
368 				      -err);
369 			if (pte_present(*pte))
370 				map_memory(addr,
371 					   pte_val(*pte) & PAGE_MASK,
372 					   PAGE_SIZE, 1, 1, 1);
373 		}
374 		else if (pte_newprot(*pte)) {
375 			updated = 1;
376 			os_protect_memory((void *) addr, PAGE_SIZE, 1, 1, 1);
377 		}
378 		addr += PAGE_SIZE;
379 	}
380 	return updated;
381 }
382 
383 void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
384 {
385 	pgd_t *pgd;
386 	pud_t *pud;
387 	pmd_t *pmd;
388 	pte_t *pte;
389 	struct mm_struct *mm = vma->vm_mm;
390 	void *flush = NULL;
391 	int r, w, x, prot, err = 0;
392 	struct mm_id *mm_id;
393 
394 	address &= PAGE_MASK;
395 	pgd = pgd_offset(mm, address);
396 	if (!pgd_present(*pgd))
397 		goto kill;
398 
399 	pud = pud_offset(pgd, address);
400 	if (!pud_present(*pud))
401 		goto kill;
402 
403 	pmd = pmd_offset(pud, address);
404 	if (!pmd_present(*pmd))
405 		goto kill;
406 
407 	pte = pte_offset_kernel(pmd, address);
408 
409 	r = pte_read(*pte);
410 	w = pte_write(*pte);
411 	x = pte_exec(*pte);
412 	if (!pte_young(*pte)) {
413 		r = 0;
414 		w = 0;
415 	} else if (!pte_dirty(*pte)) {
416 		w = 0;
417 	}
418 
419 	mm_id = &mm->context.id;
420 	prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
421 		(x ? UM_PROT_EXEC : 0));
422 	if (pte_newpage(*pte)) {
423 		if (pte_present(*pte)) {
424 			unsigned long long offset;
425 			int fd;
426 
427 			fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
428 			err = map(mm_id, address, PAGE_SIZE, prot, fd, offset,
429 				  1, &flush);
430 		}
431 		else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
432 	}
433 	else if (pte_newprot(*pte))
434 		err = protect(mm_id, address, PAGE_SIZE, prot, 1, &flush);
435 
436 	if (err)
437 		goto kill;
438 
439 	*pte = pte_mkuptodate(*pte);
440 
441 	return;
442 
443 kill:
444 	printk(KERN_ERR "Failed to flush page for address 0x%lx\n", address);
445 	force_sig(SIGKILL, current);
446 }
447 
448 pgd_t *pgd_offset_proc(struct mm_struct *mm, unsigned long address)
449 {
450 	return pgd_offset(mm, address);
451 }
452 
453 pud_t *pud_offset_proc(pgd_t *pgd, unsigned long address)
454 {
455 	return pud_offset(pgd, address);
456 }
457 
458 pmd_t *pmd_offset_proc(pud_t *pud, unsigned long address)
459 {
460 	return pmd_offset(pud, address);
461 }
462 
463 pte_t *pte_offset_proc(pmd_t *pmd, unsigned long address)
464 {
465 	return pte_offset_kernel(pmd, address);
466 }
467 
468 pte_t *addr_pte(struct task_struct *task, unsigned long addr)
469 {
470 	pgd_t *pgd = pgd_offset(task->mm, addr);
471 	pud_t *pud = pud_offset(pgd, addr);
472 	pmd_t *pmd = pmd_offset(pud, addr);
473 
474 	return pte_offset_map(pmd, addr);
475 }
476 
477 void flush_tlb_all(void)
478 {
479 	flush_tlb_mm(current->mm);
480 }
481 
482 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
483 {
484 	flush_tlb_kernel_range_common(start, end);
485 }
486 
487 void flush_tlb_kernel_vm(void)
488 {
489 	flush_tlb_kernel_range_common(start_vm, end_vm);
490 }
491 
492 void __flush_tlb_one(unsigned long addr)
493 {
494 	flush_tlb_kernel_range_common(addr, addr + PAGE_SIZE);
495 }
496 
497 static void fix_range(struct mm_struct *mm, unsigned long start_addr,
498 		      unsigned long end_addr, int force)
499 {
500 	fix_range_common(mm, start_addr, end_addr, force);
501 }
502 
503 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
504 		     unsigned long end)
505 {
506 	if (vma->vm_mm == NULL)
507 		flush_tlb_kernel_range_common(start, end);
508 	else fix_range(vma->vm_mm, start, end, 0);
509 }
510 EXPORT_SYMBOL(flush_tlb_range);
511 
512 void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
513 			unsigned long end)
514 {
515 	/*
516 	 * Don't bother flushing if this address space is about to be
517 	 * destroyed.
518 	 */
519 	if (atomic_read(&mm->mm_users) == 0)
520 		return;
521 
522 	fix_range(mm, start, end, 0);
523 }
524 
525 void flush_tlb_mm(struct mm_struct *mm)
526 {
527 	struct vm_area_struct *vma = mm->mmap;
528 
529 	while (vma != NULL) {
530 		fix_range(mm, vma->vm_start, vma->vm_end, 0);
531 		vma = vma->vm_next;
532 	}
533 }
534 
535 void force_flush_all(void)
536 {
537 	struct mm_struct *mm = current->mm;
538 	struct vm_area_struct *vma = mm->mmap;
539 
540 	while (vma != NULL) {
541 		fix_range(mm, vma->vm_start, vma->vm_end, 1);
542 		vma = vma->vm_next;
543 	}
544 }
545