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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 | ||
31 | //#define DEBUG_TB_INVALIDATE | |
32 | #define DEBUG_FLUSH | |
33 | ||
34 | /* make various TB consistency checks */ | |
35 | //#define DEBUG_TB_CHECK | |
36 | ||
37 | /* threshold to flush the translated code buffer */ | |
38 | #define CODE_GEN_BUFFER_MAX_SIZE (CODE_GEN_BUFFER_SIZE - CODE_GEN_MAX_SIZE) | |
39 | ||
40 | #define CODE_GEN_MAX_BLOCKS (CODE_GEN_BUFFER_SIZE / 64) | |
41 | ||
42 | TranslationBlock tbs[CODE_GEN_MAX_BLOCKS]; | |
43 | TranslationBlock *tb_hash[CODE_GEN_HASH_SIZE]; | |
44 | int nb_tbs; | |
45 | /* any access to the tbs or the page table must use this lock */ | |
46 | spinlock_t tb_lock = SPIN_LOCK_UNLOCKED; | |
47 | ||
48 | uint8_t code_gen_buffer[CODE_GEN_BUFFER_SIZE]; | |
49 | uint8_t *code_gen_ptr; | |
50 | ||
51 | /* XXX: pack the flags in the low bits of the pointer ? */ | |
52 | typedef struct PageDesc { | |
53 | unsigned long flags; | |
54 | TranslationBlock *first_tb; | |
55 | } PageDesc; | |
56 | ||
57 | #define L2_BITS 10 | |
58 | #define L1_BITS (32 - L2_BITS - TARGET_PAGE_BITS) | |
59 | ||
60 | #define L1_SIZE (1 << L1_BITS) | |
61 | #define L2_SIZE (1 << L2_BITS) | |
62 | ||
63 | static void tb_invalidate_page(unsigned long address); | |
64 | ||
65 | unsigned long real_host_page_size; | |
66 | unsigned long host_page_bits; | |
67 | unsigned long host_page_size; | |
68 | unsigned long host_page_mask; | |
69 | ||
70 | static PageDesc *l1_map[L1_SIZE]; | |
71 | ||
72 | void page_init(void) | |
73 | { | |
74 | /* NOTE: we can always suppose that host_page_size >= | |
75 | TARGET_PAGE_SIZE */ | |
76 | real_host_page_size = getpagesize(); | |
77 | if (host_page_size == 0) | |
78 | host_page_size = real_host_page_size; | |
79 | if (host_page_size < TARGET_PAGE_SIZE) | |
80 | host_page_size = TARGET_PAGE_SIZE; | |
81 | host_page_bits = 0; | |
82 | while ((1 << host_page_bits) < host_page_size) | |
83 | host_page_bits++; | |
84 | host_page_mask = ~(host_page_size - 1); | |
85 | } | |
86 | ||
87 | /* dump memory mappings */ | |
88 | void page_dump(FILE *f) | |
89 | { | |
90 | unsigned long start, end; | |
91 | int i, j, prot, prot1; | |
92 | PageDesc *p; | |
93 | ||
94 | fprintf(f, "%-8s %-8s %-8s %s\n", | |
95 | "start", "end", "size", "prot"); | |
96 | start = -1; | |
97 | end = -1; | |
98 | prot = 0; | |
99 | for(i = 0; i <= L1_SIZE; i++) { | |
100 | if (i < L1_SIZE) | |
101 | p = l1_map[i]; | |
102 | else | |
103 | p = NULL; | |
104 | for(j = 0;j < L2_SIZE; j++) { | |
105 | if (!p) | |
106 | prot1 = 0; | |
107 | else | |
108 | prot1 = p[j].flags; | |
109 | if (prot1 != prot) { | |
110 | end = (i << (32 - L1_BITS)) | (j << TARGET_PAGE_BITS); | |
111 | if (start != -1) { | |
112 | fprintf(f, "%08lx-%08lx %08lx %c%c%c\n", | |
113 | start, end, end - start, | |
114 | prot & PAGE_READ ? 'r' : '-', | |
115 | prot & PAGE_WRITE ? 'w' : '-', | |
116 | prot & PAGE_EXEC ? 'x' : '-'); | |
117 | } | |
118 | if (prot1 != 0) | |
119 | start = end; | |
120 | else | |
121 | start = -1; | |
122 | prot = prot1; | |
123 | } | |
124 | if (!p) | |
125 | break; | |
126 | } | |
127 | } | |
128 | } | |
129 | ||
130 | static inline PageDesc *page_find_alloc(unsigned int index) | |
131 | { | |
132 | PageDesc **lp, *p; | |
133 | ||
134 | lp = &l1_map[index >> L2_BITS]; | |
135 | p = *lp; | |
136 | if (!p) { | |
137 | /* allocate if not found */ | |
138 | p = malloc(sizeof(PageDesc) * L2_SIZE); | |
139 | memset(p, 0, sizeof(PageDesc) * L2_SIZE); | |
140 | *lp = p; | |
141 | } | |
142 | return p + (index & (L2_SIZE - 1)); | |
143 | } | |
144 | ||
145 | static inline PageDesc *page_find(unsigned int index) | |
146 | { | |
147 | PageDesc *p; | |
148 | ||
149 | p = l1_map[index >> L2_BITS]; | |
150 | if (!p) | |
151 | return 0; | |
152 | return p + (index & (L2_SIZE - 1)); | |
153 | } | |
154 | ||
155 | int page_get_flags(unsigned long address) | |
156 | { | |
157 | PageDesc *p; | |
158 | ||
159 | p = page_find(address >> TARGET_PAGE_BITS); | |
160 | if (!p) | |
161 | return 0; | |
162 | return p->flags; | |
163 | } | |
164 | ||
165 | /* modify the flags of a page and invalidate the code if | |
166 | necessary. The flag PAGE_WRITE_ORG is positionned automatically | |
167 | depending on PAGE_WRITE */ | |
168 | void page_set_flags(unsigned long start, unsigned long end, int flags) | |
169 | { | |
170 | PageDesc *p; | |
171 | unsigned long addr; | |
172 | ||
173 | start = start & TARGET_PAGE_MASK; | |
174 | end = TARGET_PAGE_ALIGN(end); | |
175 | if (flags & PAGE_WRITE) | |
176 | flags |= PAGE_WRITE_ORG; | |
177 | spin_lock(&tb_lock); | |
178 | for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) { | |
179 | p = page_find_alloc(addr >> TARGET_PAGE_BITS); | |
180 | /* if the write protection is set, then we invalidate the code | |
181 | inside */ | |
182 | if (!(p->flags & PAGE_WRITE) && | |
183 | (flags & PAGE_WRITE) && | |
184 | p->first_tb) { | |
185 | tb_invalidate_page(addr); | |
186 | } | |
187 | p->flags = flags; | |
188 | } | |
189 | spin_unlock(&tb_lock); | |
190 | } | |
191 | ||
192 | void cpu_x86_tblocks_init(void) | |
193 | { | |
194 | if (!code_gen_ptr) { | |
195 | code_gen_ptr = code_gen_buffer; | |
196 | } | |
197 | } | |
198 | ||
199 | /* set to NULL all the 'first_tb' fields in all PageDescs */ | |
200 | static void page_flush_tb(void) | |
201 | { | |
202 | int i, j; | |
203 | PageDesc *p; | |
204 | ||
205 | for(i = 0; i < L1_SIZE; i++) { | |
206 | p = l1_map[i]; | |
207 | if (p) { | |
208 | for(j = 0; j < L2_SIZE; j++) | |
209 | p[j].first_tb = NULL; | |
210 | } | |
211 | } | |
212 | } | |
213 | ||
214 | /* flush all the translation blocks */ | |
215 | void tb_flush(void) | |
216 | { | |
217 | int i; | |
218 | #ifdef DEBUG_FLUSH | |
219 | printf("qemu: flush code_size=%d nb_tbs=%d avg_tb_size=%d\n", | |
220 | code_gen_ptr - code_gen_buffer, | |
221 | nb_tbs, | |
222 | (code_gen_ptr - code_gen_buffer) / nb_tbs); | |
223 | #endif | |
224 | nb_tbs = 0; | |
225 | for(i = 0;i < CODE_GEN_HASH_SIZE; i++) | |
226 | tb_hash[i] = NULL; | |
227 | page_flush_tb(); | |
228 | code_gen_ptr = code_gen_buffer; | |
229 | /* XXX: flush processor icache at this point */ | |
230 | } | |
231 | ||
232 | #ifdef DEBUG_TB_CHECK | |
233 | ||
234 | static void tb_invalidate_check(unsigned long address) | |
235 | { | |
236 | TranslationBlock *tb; | |
237 | int i; | |
238 | address &= TARGET_PAGE_MASK; | |
239 | for(i = 0;i < CODE_GEN_HASH_SIZE; i++) { | |
240 | for(tb = tb_hash[i]; tb != NULL; tb = tb->hash_next) { | |
241 | if (!(address + TARGET_PAGE_SIZE <= tb->pc || | |
242 | address >= tb->pc + tb->size)) { | |
243 | printf("ERROR invalidate: address=%08lx PC=%08lx size=%04x\n", | |
244 | address, tb->pc, tb->size); | |
245 | } | |
246 | } | |
247 | } | |
248 | } | |
249 | ||
250 | /* verify that all the pages have correct rights for code */ | |
251 | static void tb_page_check(void) | |
252 | { | |
253 | TranslationBlock *tb; | |
254 | int i, flags1, flags2; | |
255 | ||
256 | for(i = 0;i < CODE_GEN_HASH_SIZE; i++) { | |
257 | for(tb = tb_hash[i]; tb != NULL; tb = tb->hash_next) { | |
258 | flags1 = page_get_flags(tb->pc); | |
259 | flags2 = page_get_flags(tb->pc + tb->size - 1); | |
260 | if ((flags1 & PAGE_WRITE) || (flags2 & PAGE_WRITE)) { | |
261 | printf("ERROR page flags: PC=%08lx size=%04x f1=%x f2=%x\n", | |
262 | tb->pc, tb->size, flags1, flags2); | |
263 | } | |
264 | } | |
265 | } | |
266 | } | |
267 | ||
268 | #endif | |
269 | ||
270 | /* invalidate one TB */ | |
271 | static inline void tb_remove(TranslationBlock **ptb, TranslationBlock *tb, | |
272 | int next_offset) | |
273 | { | |
274 | TranslationBlock *tb1; | |
275 | for(;;) { | |
276 | tb1 = *ptb; | |
277 | if (tb1 == tb) { | |
278 | *ptb = *(TranslationBlock **)((char *)tb1 + next_offset); | |
279 | break; | |
280 | } | |
281 | ptb = (TranslationBlock **)((char *)tb1 + next_offset); | |
282 | } | |
283 | } | |
284 | ||
285 | static inline void tb_invalidate(TranslationBlock *tb, int parity) | |
286 | { | |
287 | PageDesc *p; | |
288 | unsigned int page_index1, page_index2; | |
289 | unsigned int h; | |
290 | ||
291 | /* remove the TB from the hash list */ | |
292 | h = tb_hash_func(tb->pc); | |
293 | tb_remove(&tb_hash[h], tb, | |
294 | offsetof(TranslationBlock, hash_next)); | |
295 | /* remove the TB from the page list */ | |
296 | page_index1 = tb->pc >> TARGET_PAGE_BITS; | |
297 | if ((page_index1 & 1) == parity) { | |
298 | p = page_find(page_index1); | |
299 | tb_remove(&p->first_tb, tb, | |
300 | offsetof(TranslationBlock, page_next[page_index1 & 1])); | |
301 | } | |
302 | page_index2 = (tb->pc + tb->size - 1) >> TARGET_PAGE_BITS; | |
303 | if ((page_index2 & 1) == parity) { | |
304 | p = page_find(page_index2); | |
305 | tb_remove(&p->first_tb, tb, | |
306 | offsetof(TranslationBlock, page_next[page_index2 & 1])); | |
307 | } | |
308 | } | |
309 | ||
310 | /* invalidate all TBs which intersect with the target page starting at addr */ | |
311 | static void tb_invalidate_page(unsigned long address) | |
312 | { | |
313 | TranslationBlock *tb_next, *tb; | |
314 | unsigned int page_index; | |
315 | int parity1, parity2; | |
316 | PageDesc *p; | |
317 | #ifdef DEBUG_TB_INVALIDATE | |
318 | printf("tb_invalidate_page: %lx\n", address); | |
319 | #endif | |
320 | ||
321 | page_index = address >> TARGET_PAGE_BITS; | |
322 | p = page_find(page_index); | |
323 | if (!p) | |
324 | return; | |
325 | tb = p->first_tb; | |
326 | parity1 = page_index & 1; | |
327 | parity2 = parity1 ^ 1; | |
328 | while (tb != NULL) { | |
329 | tb_next = tb->page_next[parity1]; | |
330 | tb_invalidate(tb, parity2); | |
331 | tb = tb_next; | |
332 | } | |
333 | p->first_tb = NULL; | |
334 | } | |
335 | ||
336 | /* add the tb in the target page and protect it if necessary */ | |
337 | static inline void tb_alloc_page(TranslationBlock *tb, unsigned int page_index) | |
338 | { | |
339 | PageDesc *p; | |
340 | unsigned long host_start, host_end, addr, page_addr; | |
341 | int prot; | |
342 | ||
343 | p = page_find_alloc(page_index); | |
344 | tb->page_next[page_index & 1] = p->first_tb; | |
345 | p->first_tb = tb; | |
346 | if (p->flags & PAGE_WRITE) { | |
347 | /* force the host page as non writable (writes will have a | |
348 | page fault + mprotect overhead) */ | |
349 | page_addr = (page_index << TARGET_PAGE_BITS); | |
350 | host_start = page_addr & host_page_mask; | |
351 | host_end = host_start + host_page_size; | |
352 | prot = 0; | |
353 | for(addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE) | |
354 | prot |= page_get_flags(addr); | |
355 | mprotect((void *)host_start, host_page_size, | |
356 | (prot & PAGE_BITS) & ~PAGE_WRITE); | |
357 | #ifdef DEBUG_TB_INVALIDATE | |
358 | printf("protecting code page: 0x%08lx\n", | |
359 | host_start); | |
360 | #endif | |
361 | p->flags &= ~PAGE_WRITE; | |
362 | #ifdef DEBUG_TB_CHECK | |
363 | tb_page_check(); | |
364 | #endif | |
365 | } | |
366 | } | |
367 | ||
368 | /* Allocate a new translation block. Flush the translation buffer if | |
369 | too many translation blocks or too much generated code. */ | |
370 | TranslationBlock *tb_alloc(unsigned long pc, | |
371 | unsigned long size) | |
372 | { | |
373 | TranslationBlock *tb; | |
374 | unsigned int page_index1, page_index2; | |
375 | ||
376 | if (nb_tbs >= CODE_GEN_MAX_BLOCKS || | |
377 | (code_gen_ptr - code_gen_buffer) >= CODE_GEN_BUFFER_MAX_SIZE) | |
378 | tb_flush(); | |
379 | tb = &tbs[nb_tbs++]; | |
380 | tb->pc = pc; | |
381 | tb->size = size; | |
382 | ||
383 | /* add in the page list */ | |
384 | page_index1 = pc >> TARGET_PAGE_BITS; | |
385 | tb_alloc_page(tb, page_index1); | |
386 | page_index2 = (pc + size - 1) >> TARGET_PAGE_BITS; | |
387 | if (page_index2 != page_index1) { | |
388 | tb_alloc_page(tb, page_index2); | |
389 | } | |
390 | return tb; | |
391 | } | |
392 | ||
393 | /* called from signal handler: invalidate the code and unprotect the | |
394 | page. Return TRUE if the fault was succesfully handled. */ | |
395 | int page_unprotect(unsigned long address) | |
396 | { | |
397 | unsigned int page_index, prot; | |
398 | PageDesc *p; | |
399 | unsigned long host_start, host_end, addr; | |
400 | ||
401 | page_index = address >> TARGET_PAGE_BITS; | |
402 | p = page_find(page_index); | |
403 | if (!p) | |
404 | return 0; | |
405 | if ((p->flags & (PAGE_WRITE_ORG | PAGE_WRITE)) == PAGE_WRITE_ORG) { | |
406 | /* if the page was really writable, then we change its | |
407 | protection back to writable */ | |
408 | host_start = address & host_page_mask; | |
409 | host_end = host_start + host_page_size; | |
410 | prot = 0; | |
411 | for(addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE) | |
412 | prot |= page_get_flags(addr); | |
413 | mprotect((void *)host_start, host_page_size, | |
414 | (prot & PAGE_BITS) | PAGE_WRITE); | |
415 | p->flags |= PAGE_WRITE; | |
416 | ||
417 | /* and since the content will be modified, we must invalidate | |
418 | the corresponding translated code. */ | |
419 | tb_invalidate_page(address); | |
420 | #ifdef DEBUG_TB_CHECK | |
421 | tb_invalidate_check(address); | |
422 | #endif | |
423 | return 1; | |
424 | } else { | |
425 | return 0; | |
426 | } | |
427 | } | |
428 | ||
429 | /* call this function when system calls directly modify a memory area */ | |
430 | void page_unprotect_range(uint8_t *data, unsigned long data_size) | |
431 | { | |
432 | unsigned long start, end, addr; | |
433 | ||
434 | start = (unsigned long)data; | |
435 | end = start + data_size; | |
436 | start &= TARGET_PAGE_MASK; | |
437 | end = TARGET_PAGE_ALIGN(end); | |
438 | for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) { | |
439 | page_unprotect(addr); | |
440 | } | |
441 | } |