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1 | /* | |
2 | * virtual page mapping and translated block handling | |
3 | * | |
4 | * Copyright (c) 2003 Fabrice Bellard | |
5 | * | |
6 | * This library is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, write to the Free Software | |
18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
19 | */ | |
20 | #include <stdlib.h> | |
21 | #include <stdio.h> | |
22 | #include <stdarg.h> | |
23 | #include <string.h> | |
24 | #include <errno.h> | |
25 | #include <unistd.h> | |
26 | #include <inttypes.h> | |
27 | #include <sys/mman.h> | |
28 | ||
29 | #include "cpu-i386.h" | |
30 | #include "exec.h" | |
31 | ||
32 | //#define DEBUG_TB_INVALIDATE | |
33 | #define DEBUG_FLUSH | |
34 | ||
35 | /* make various TB consistency checks */ | |
36 | //#define DEBUG_TB_CHECK | |
37 | ||
38 | /* threshold to flush the translated code buffer */ | |
39 | #define CODE_GEN_BUFFER_MAX_SIZE (CODE_GEN_BUFFER_SIZE - CODE_GEN_MAX_SIZE) | |
40 | ||
41 | #define CODE_GEN_MAX_BLOCKS (CODE_GEN_BUFFER_SIZE / 64) | |
42 | ||
43 | TranslationBlock tbs[CODE_GEN_MAX_BLOCKS]; | |
44 | TranslationBlock *tb_hash[CODE_GEN_HASH_SIZE]; | |
45 | int nb_tbs; | |
46 | /* any access to the tbs or the page table must use this lock */ | |
47 | spinlock_t tb_lock = SPIN_LOCK_UNLOCKED; | |
48 | ||
49 | uint8_t code_gen_buffer[CODE_GEN_BUFFER_SIZE]; | |
50 | uint8_t *code_gen_ptr; | |
51 | ||
52 | /* XXX: pack the flags in the low bits of the pointer ? */ | |
53 | typedef struct PageDesc { | |
54 | unsigned long flags; | |
55 | TranslationBlock *first_tb; | |
56 | } PageDesc; | |
57 | ||
58 | #define L2_BITS 10 | |
59 | #define L1_BITS (32 - L2_BITS - TARGET_PAGE_BITS) | |
60 | ||
61 | #define L1_SIZE (1 << L1_BITS) | |
62 | #define L2_SIZE (1 << L2_BITS) | |
63 | ||
64 | static void tb_invalidate_page(unsigned long address); | |
65 | ||
66 | unsigned long real_host_page_size; | |
67 | unsigned long host_page_bits; | |
68 | unsigned long host_page_size; | |
69 | unsigned long host_page_mask; | |
70 | ||
71 | static PageDesc *l1_map[L1_SIZE]; | |
72 | ||
73 | void page_init(void) | |
74 | { | |
75 | /* NOTE: we can always suppose that host_page_size >= | |
76 | TARGET_PAGE_SIZE */ | |
77 | real_host_page_size = getpagesize(); | |
78 | if (host_page_size == 0) | |
79 | host_page_size = real_host_page_size; | |
80 | if (host_page_size < TARGET_PAGE_SIZE) | |
81 | host_page_size = TARGET_PAGE_SIZE; | |
82 | host_page_bits = 0; | |
83 | while ((1 << host_page_bits) < host_page_size) | |
84 | host_page_bits++; | |
85 | host_page_mask = ~(host_page_size - 1); | |
86 | } | |
87 | ||
88 | /* dump memory mappings */ | |
89 | void page_dump(FILE *f) | |
90 | { | |
91 | unsigned long start, end; | |
92 | int i, j, prot, prot1; | |
93 | PageDesc *p; | |
94 | ||
95 | fprintf(f, "%-8s %-8s %-8s %s\n", | |
96 | "start", "end", "size", "prot"); | |
97 | start = -1; | |
98 | end = -1; | |
99 | prot = 0; | |
100 | for(i = 0; i <= L1_SIZE; i++) { | |
101 | if (i < L1_SIZE) | |
102 | p = l1_map[i]; | |
103 | else | |
104 | p = NULL; | |
105 | for(j = 0;j < L2_SIZE; j++) { | |
106 | if (!p) | |
107 | prot1 = 0; | |
108 | else | |
109 | prot1 = p[j].flags; | |
110 | if (prot1 != prot) { | |
111 | end = (i << (32 - L1_BITS)) | (j << TARGET_PAGE_BITS); | |
112 | if (start != -1) { | |
113 | fprintf(f, "%08lx-%08lx %08lx %c%c%c\n", | |
114 | start, end, end - start, | |
115 | prot & PAGE_READ ? 'r' : '-', | |
116 | prot & PAGE_WRITE ? 'w' : '-', | |
117 | prot & PAGE_EXEC ? 'x' : '-'); | |
118 | } | |
119 | if (prot1 != 0) | |
120 | start = end; | |
121 | else | |
122 | start = -1; | |
123 | prot = prot1; | |
124 | } | |
125 | if (!p) | |
126 | break; | |
127 | } | |
128 | } | |
129 | } | |
130 | ||
131 | static inline PageDesc *page_find_alloc(unsigned int index) | |
132 | { | |
133 | PageDesc **lp, *p; | |
134 | ||
135 | lp = &l1_map[index >> L2_BITS]; | |
136 | p = *lp; | |
137 | if (!p) { | |
138 | /* allocate if not found */ | |
139 | p = malloc(sizeof(PageDesc) * L2_SIZE); | |
140 | memset(p, 0, sizeof(PageDesc) * L2_SIZE); | |
141 | *lp = p; | |
142 | } | |
143 | return p + (index & (L2_SIZE - 1)); | |
144 | } | |
145 | ||
146 | static inline PageDesc *page_find(unsigned int index) | |
147 | { | |
148 | PageDesc *p; | |
149 | ||
150 | p = l1_map[index >> L2_BITS]; | |
151 | if (!p) | |
152 | return 0; | |
153 | return p + (index & (L2_SIZE - 1)); | |
154 | } | |
155 | ||
156 | int page_get_flags(unsigned long address) | |
157 | { | |
158 | PageDesc *p; | |
159 | ||
160 | p = page_find(address >> TARGET_PAGE_BITS); | |
161 | if (!p) | |
162 | return 0; | |
163 | return p->flags; | |
164 | } | |
165 | ||
166 | /* modify the flags of a page and invalidate the code if | |
167 | necessary. The flag PAGE_WRITE_ORG is positionned automatically | |
168 | depending on PAGE_WRITE */ | |
169 | void page_set_flags(unsigned long start, unsigned long end, int flags) | |
170 | { | |
171 | PageDesc *p; | |
172 | unsigned long addr; | |
173 | ||
174 | start = start & TARGET_PAGE_MASK; | |
175 | end = TARGET_PAGE_ALIGN(end); | |
176 | if (flags & PAGE_WRITE) | |
177 | flags |= PAGE_WRITE_ORG; | |
178 | spin_lock(&tb_lock); | |
179 | for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) { | |
180 | p = page_find_alloc(addr >> TARGET_PAGE_BITS); | |
181 | /* if the write protection is set, then we invalidate the code | |
182 | inside */ | |
183 | if (!(p->flags & PAGE_WRITE) && | |
184 | (flags & PAGE_WRITE) && | |
185 | p->first_tb) { | |
186 | tb_invalidate_page(addr); | |
187 | } | |
188 | p->flags = flags; | |
189 | } | |
190 | spin_unlock(&tb_lock); | |
191 | } | |
192 | ||
193 | void cpu_x86_tblocks_init(void) | |
194 | { | |
195 | if (!code_gen_ptr) { | |
196 | code_gen_ptr = code_gen_buffer; | |
197 | } | |
198 | } | |
199 | ||
200 | /* set to NULL all the 'first_tb' fields in all PageDescs */ | |
201 | static void page_flush_tb(void) | |
202 | { | |
203 | int i, j; | |
204 | PageDesc *p; | |
205 | ||
206 | for(i = 0; i < L1_SIZE; i++) { | |
207 | p = l1_map[i]; | |
208 | if (p) { | |
209 | for(j = 0; j < L2_SIZE; j++) | |
210 | p[j].first_tb = NULL; | |
211 | } | |
212 | } | |
213 | } | |
214 | ||
215 | /* flush all the translation blocks */ | |
216 | /* XXX: tb_flush is currently not thread safe */ | |
217 | void tb_flush(void) | |
218 | { | |
219 | int i; | |
220 | #ifdef DEBUG_FLUSH | |
221 | printf("qemu: flush code_size=%d nb_tbs=%d avg_tb_size=%d\n", | |
222 | code_gen_ptr - code_gen_buffer, | |
223 | nb_tbs, | |
224 | (code_gen_ptr - code_gen_buffer) / nb_tbs); | |
225 | #endif | |
226 | nb_tbs = 0; | |
227 | for(i = 0;i < CODE_GEN_HASH_SIZE; i++) | |
228 | tb_hash[i] = NULL; | |
229 | page_flush_tb(); | |
230 | code_gen_ptr = code_gen_buffer; | |
231 | /* XXX: flush processor icache at this point if cache flush is | |
232 | expensive */ | |
233 | } | |
234 | ||
235 | #ifdef DEBUG_TB_CHECK | |
236 | ||
237 | static void tb_invalidate_check(unsigned long address) | |
238 | { | |
239 | TranslationBlock *tb; | |
240 | int i; | |
241 | address &= TARGET_PAGE_MASK; | |
242 | for(i = 0;i < CODE_GEN_HASH_SIZE; i++) { | |
243 | for(tb = tb_hash[i]; tb != NULL; tb = tb->hash_next) { | |
244 | if (!(address + TARGET_PAGE_SIZE <= tb->pc || | |
245 | address >= tb->pc + tb->size)) { | |
246 | printf("ERROR invalidate: address=%08lx PC=%08lx size=%04x\n", | |
247 | address, tb->pc, tb->size); | |
248 | } | |
249 | } | |
250 | } | |
251 | } | |
252 | ||
253 | /* verify that all the pages have correct rights for code */ | |
254 | static void tb_page_check(void) | |
255 | { | |
256 | TranslationBlock *tb; | |
257 | int i, flags1, flags2; | |
258 | ||
259 | for(i = 0;i < CODE_GEN_HASH_SIZE; i++) { | |
260 | for(tb = tb_hash[i]; tb != NULL; tb = tb->hash_next) { | |
261 | flags1 = page_get_flags(tb->pc); | |
262 | flags2 = page_get_flags(tb->pc + tb->size - 1); | |
263 | if ((flags1 & PAGE_WRITE) || (flags2 & PAGE_WRITE)) { | |
264 | printf("ERROR page flags: PC=%08lx size=%04x f1=%x f2=%x\n", | |
265 | tb->pc, tb->size, flags1, flags2); | |
266 | } | |
267 | } | |
268 | } | |
269 | } | |
270 | ||
271 | void tb_jmp_check(TranslationBlock *tb) | |
272 | { | |
273 | TranslationBlock *tb1; | |
274 | unsigned int n1; | |
275 | ||
276 | /* suppress any remaining jumps to this TB */ | |
277 | tb1 = tb->jmp_first; | |
278 | for(;;) { | |
279 | n1 = (long)tb1 & 3; | |
280 | tb1 = (TranslationBlock *)((long)tb1 & ~3); | |
281 | if (n1 == 2) | |
282 | break; | |
283 | tb1 = tb1->jmp_next[n1]; | |
284 | } | |
285 | /* check end of list */ | |
286 | if (tb1 != tb) { | |
287 | printf("ERROR: jmp_list from 0x%08lx\n", (long)tb); | |
288 | } | |
289 | } | |
290 | ||
291 | #endif | |
292 | ||
293 | /* invalidate one TB */ | |
294 | static inline void tb_remove(TranslationBlock **ptb, TranslationBlock *tb, | |
295 | int next_offset) | |
296 | { | |
297 | TranslationBlock *tb1; | |
298 | for(;;) { | |
299 | tb1 = *ptb; | |
300 | if (tb1 == tb) { | |
301 | *ptb = *(TranslationBlock **)((char *)tb1 + next_offset); | |
302 | break; | |
303 | } | |
304 | ptb = (TranslationBlock **)((char *)tb1 + next_offset); | |
305 | } | |
306 | } | |
307 | ||
308 | static inline void tb_jmp_remove(TranslationBlock *tb, int n) | |
309 | { | |
310 | TranslationBlock *tb1, **ptb; | |
311 | unsigned int n1; | |
312 | ||
313 | ptb = &tb->jmp_next[n]; | |
314 | tb1 = *ptb; | |
315 | if (tb1) { | |
316 | /* find tb(n) in circular list */ | |
317 | for(;;) { | |
318 | tb1 = *ptb; | |
319 | n1 = (long)tb1 & 3; | |
320 | tb1 = (TranslationBlock *)((long)tb1 & ~3); | |
321 | if (n1 == n && tb1 == tb) | |
322 | break; | |
323 | if (n1 == 2) { | |
324 | ptb = &tb1->jmp_first; | |
325 | } else { | |
326 | ptb = &tb1->jmp_next[n1]; | |
327 | } | |
328 | } | |
329 | /* now we can suppress tb(n) from the list */ | |
330 | *ptb = tb->jmp_next[n]; | |
331 | ||
332 | tb->jmp_next[n] = NULL; | |
333 | } | |
334 | } | |
335 | ||
336 | /* reset the jump entry 'n' of a TB so that it is not chained to | |
337 | another TB */ | |
338 | static inline void tb_reset_jump(TranslationBlock *tb, int n) | |
339 | { | |
340 | tb_set_jmp_target(tb, n, (unsigned long)(tb->tc_ptr + tb->tb_next_offset[n])); | |
341 | } | |
342 | ||
343 | static inline void tb_invalidate(TranslationBlock *tb, int parity) | |
344 | { | |
345 | PageDesc *p; | |
346 | unsigned int page_index1, page_index2; | |
347 | unsigned int h, n1; | |
348 | TranslationBlock *tb1, *tb2; | |
349 | ||
350 | /* remove the TB from the hash list */ | |
351 | h = tb_hash_func(tb->pc); | |
352 | tb_remove(&tb_hash[h], tb, | |
353 | offsetof(TranslationBlock, hash_next)); | |
354 | /* remove the TB from the page list */ | |
355 | page_index1 = tb->pc >> TARGET_PAGE_BITS; | |
356 | if ((page_index1 & 1) == parity) { | |
357 | p = page_find(page_index1); | |
358 | tb_remove(&p->first_tb, tb, | |
359 | offsetof(TranslationBlock, page_next[page_index1 & 1])); | |
360 | } | |
361 | page_index2 = (tb->pc + tb->size - 1) >> TARGET_PAGE_BITS; | |
362 | if ((page_index2 & 1) == parity) { | |
363 | p = page_find(page_index2); | |
364 | tb_remove(&p->first_tb, tb, | |
365 | offsetof(TranslationBlock, page_next[page_index2 & 1])); | |
366 | } | |
367 | ||
368 | /* suppress this TB from the two jump lists */ | |
369 | tb_jmp_remove(tb, 0); | |
370 | tb_jmp_remove(tb, 1); | |
371 | ||
372 | /* suppress any remaining jumps to this TB */ | |
373 | tb1 = tb->jmp_first; | |
374 | for(;;) { | |
375 | n1 = (long)tb1 & 3; | |
376 | if (n1 == 2) | |
377 | break; | |
378 | tb1 = (TranslationBlock *)((long)tb1 & ~3); | |
379 | tb2 = tb1->jmp_next[n1]; | |
380 | tb_reset_jump(tb1, n1); | |
381 | tb1->jmp_next[n1] = NULL; | |
382 | tb1 = tb2; | |
383 | } | |
384 | tb->jmp_first = (TranslationBlock *)((long)tb | 2); /* fail safe */ | |
385 | } | |
386 | ||
387 | /* invalidate all TBs which intersect with the target page starting at addr */ | |
388 | static void tb_invalidate_page(unsigned long address) | |
389 | { | |
390 | TranslationBlock *tb_next, *tb; | |
391 | unsigned int page_index; | |
392 | int parity1, parity2; | |
393 | PageDesc *p; | |
394 | #ifdef DEBUG_TB_INVALIDATE | |
395 | printf("tb_invalidate_page: %lx\n", address); | |
396 | #endif | |
397 | ||
398 | page_index = address >> TARGET_PAGE_BITS; | |
399 | p = page_find(page_index); | |
400 | if (!p) | |
401 | return; | |
402 | tb = p->first_tb; | |
403 | parity1 = page_index & 1; | |
404 | parity2 = parity1 ^ 1; | |
405 | while (tb != NULL) { | |
406 | tb_next = tb->page_next[parity1]; | |
407 | tb_invalidate(tb, parity2); | |
408 | tb = tb_next; | |
409 | } | |
410 | p->first_tb = NULL; | |
411 | } | |
412 | ||
413 | /* add the tb in the target page and protect it if necessary */ | |
414 | static inline void tb_alloc_page(TranslationBlock *tb, unsigned int page_index) | |
415 | { | |
416 | PageDesc *p; | |
417 | unsigned long host_start, host_end, addr, page_addr; | |
418 | int prot; | |
419 | ||
420 | p = page_find_alloc(page_index); | |
421 | tb->page_next[page_index & 1] = p->first_tb; | |
422 | p->first_tb = tb; | |
423 | if (p->flags & PAGE_WRITE) { | |
424 | /* force the host page as non writable (writes will have a | |
425 | page fault + mprotect overhead) */ | |
426 | page_addr = (page_index << TARGET_PAGE_BITS); | |
427 | host_start = page_addr & host_page_mask; | |
428 | host_end = host_start + host_page_size; | |
429 | prot = 0; | |
430 | for(addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE) | |
431 | prot |= page_get_flags(addr); | |
432 | mprotect((void *)host_start, host_page_size, | |
433 | (prot & PAGE_BITS) & ~PAGE_WRITE); | |
434 | #ifdef DEBUG_TB_INVALIDATE | |
435 | printf("protecting code page: 0x%08lx\n", | |
436 | host_start); | |
437 | #endif | |
438 | p->flags &= ~PAGE_WRITE; | |
439 | #ifdef DEBUG_TB_CHECK | |
440 | tb_page_check(); | |
441 | #endif | |
442 | } | |
443 | } | |
444 | ||
445 | /* Allocate a new translation block. Flush the translation buffer if | |
446 | too many translation blocks or too much generated code. */ | |
447 | TranslationBlock *tb_alloc(unsigned long pc) | |
448 | { | |
449 | TranslationBlock *tb; | |
450 | ||
451 | if (nb_tbs >= CODE_GEN_MAX_BLOCKS || | |
452 | (code_gen_ptr - code_gen_buffer) >= CODE_GEN_BUFFER_MAX_SIZE) | |
453 | return NULL; | |
454 | tb = &tbs[nb_tbs++]; | |
455 | tb->pc = pc; | |
456 | return tb; | |
457 | } | |
458 | ||
459 | /* link the tb with the other TBs */ | |
460 | void tb_link(TranslationBlock *tb) | |
461 | { | |
462 | unsigned int page_index1, page_index2; | |
463 | ||
464 | /* add in the page list */ | |
465 | page_index1 = tb->pc >> TARGET_PAGE_BITS; | |
466 | tb_alloc_page(tb, page_index1); | |
467 | page_index2 = (tb->pc + tb->size - 1) >> TARGET_PAGE_BITS; | |
468 | if (page_index2 != page_index1) { | |
469 | tb_alloc_page(tb, page_index2); | |
470 | } | |
471 | tb->jmp_first = (TranslationBlock *)((long)tb | 2); | |
472 | tb->jmp_next[0] = NULL; | |
473 | tb->jmp_next[1] = NULL; | |
474 | ||
475 | /* init original jump addresses */ | |
476 | if (tb->tb_next_offset[0] != 0xffff) | |
477 | tb_reset_jump(tb, 0); | |
478 | if (tb->tb_next_offset[1] != 0xffff) | |
479 | tb_reset_jump(tb, 1); | |
480 | } | |
481 | ||
482 | /* called from signal handler: invalidate the code and unprotect the | |
483 | page. Return TRUE if the fault was succesfully handled. */ | |
484 | int page_unprotect(unsigned long address) | |
485 | { | |
486 | unsigned int page_index, prot, pindex; | |
487 | PageDesc *p, *p1; | |
488 | unsigned long host_start, host_end, addr; | |
489 | ||
490 | host_start = address & host_page_mask; | |
491 | page_index = host_start >> TARGET_PAGE_BITS; | |
492 | p1 = page_find(page_index); | |
493 | if (!p1) | |
494 | return 0; | |
495 | host_end = host_start + host_page_size; | |
496 | p = p1; | |
497 | prot = 0; | |
498 | for(addr = host_start;addr < host_end; addr += TARGET_PAGE_SIZE) { | |
499 | prot |= p->flags; | |
500 | p++; | |
501 | } | |
502 | /* if the page was really writable, then we change its | |
503 | protection back to writable */ | |
504 | if (prot & PAGE_WRITE_ORG) { | |
505 | mprotect((void *)host_start, host_page_size, | |
506 | (prot & PAGE_BITS) | PAGE_WRITE); | |
507 | pindex = (address - host_start) >> TARGET_PAGE_BITS; | |
508 | p1[pindex].flags |= PAGE_WRITE; | |
509 | /* and since the content will be modified, we must invalidate | |
510 | the corresponding translated code. */ | |
511 | tb_invalidate_page(address); | |
512 | #ifdef DEBUG_TB_CHECK | |
513 | tb_invalidate_check(address); | |
514 | #endif | |
515 | return 1; | |
516 | } else { | |
517 | return 0; | |
518 | } | |
519 | } | |
520 | ||
521 | /* call this function when system calls directly modify a memory area */ | |
522 | void page_unprotect_range(uint8_t *data, unsigned long data_size) | |
523 | { | |
524 | unsigned long start, end, addr; | |
525 | ||
526 | start = (unsigned long)data; | |
527 | end = start + data_size; | |
528 | start &= TARGET_PAGE_MASK; | |
529 | end = TARGET_PAGE_ALIGN(end); | |
530 | for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) { | |
531 | page_unprotect(addr); | |
532 | } | |
533 | } | |
534 | ||
535 | /* find the TB 'tb' such that tb[0].tc_ptr <= tc_ptr < | |
536 | tb[1].tc_ptr. Return NULL if not found */ | |
537 | TranslationBlock *tb_find_pc(unsigned long tc_ptr) | |
538 | { | |
539 | int m_min, m_max, m; | |
540 | unsigned long v; | |
541 | TranslationBlock *tb; | |
542 | ||
543 | if (nb_tbs <= 0) | |
544 | return NULL; | |
545 | if (tc_ptr < (unsigned long)code_gen_buffer || | |
546 | tc_ptr >= (unsigned long)code_gen_ptr) | |
547 | return NULL; | |
548 | /* binary search (cf Knuth) */ | |
549 | m_min = 0; | |
550 | m_max = nb_tbs - 1; | |
551 | while (m_min <= m_max) { | |
552 | m = (m_min + m_max) >> 1; | |
553 | tb = &tbs[m]; | |
554 | v = (unsigned long)tb->tc_ptr; | |
555 | if (v == tc_ptr) | |
556 | return tb; | |
557 | else if (tc_ptr < v) { | |
558 | m_max = m - 1; | |
559 | } else { | |
560 | m_min = m + 1; | |
561 | } | |
562 | } | |
563 | return &tbs[m_max]; | |
564 | } |