gwj / at91sam9263 · Commits

Commit c8a706fe6242a553960ccc3071a4e75ceba6f3d2

Authored by pbrook
1 parent 30813cea

Multithreaded locking for mmap(). 


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4654 c046a42c-6fe2-441c-8c8c-71466251a162
Inline Side-by-side
Showing 3 changed files with 98 additions and 28 deletions
... ... @@ -234,6 +234,7 @@ static void page_init(void)
234 234 FILE *f;
235 235 int n;
236 236  
  237 + mmap_lock();
237 238 last_brk = (unsigned long)sbrk(0);
238 239 f = fopen("/proc/self/maps", "r");
239 240 if (f) {
... ... @@ -251,6 +252,7 @@ static void page_init(void)
251 252 } while (!feof(f));
252 253 fclose(f);
253 254 }
  255 + mmap_unlock();
254 256 }
255 257 #endif
256 258 }
... ... @@ -326,6 +328,8 @@ static inline PhysPageDesc *phys_page_find(target_phys_addr_t index)
326 328 static void tlb_protect_code(ram_addr_t ram_addr);
327 329 static void tlb_unprotect_code_phys(CPUState *env, ram_addr_t ram_addr,
328 330 target_ulong vaddr);
  331 +#define mmap_lock() do { } while(0)
  332 +#define mmap_unlock() do { } while(0)
329 333 #endif
330 334  
331 335 #define DEFAULT_CODE_GEN_BUFFER_SIZE (32 * 1024 * 1024)
... ... @@ -1049,6 +1053,9 @@ void tb_link_phys(TranslationBlock *tb,
1049 1053 unsigned int h;
1050 1054 TranslationBlock **ptb;
1051 1055  
  1056 + /* Grab the mmap lock to stop another thread invalidating this TB
  1057 + before we are done. */
  1058 + mmap_lock();
1052 1059 /* add in the physical hash table */
1053 1060 h = tb_phys_hash_func(phys_pc);
1054 1061 ptb = &tb_phys_hash[h];
... ... @@ -1075,6 +1082,7 @@ void tb_link_phys(TranslationBlock *tb,
1075 1082 #ifdef DEBUG_TB_CHECK
1076 1083 tb_page_check();
1077 1084 #endif
  1085 + mmap_unlock();
1078 1086 }
1079 1087  
1080 1088 /* find the TB 'tb' such that tb[0].tc_ptr <= tc_ptr <
... ... @@ -2002,6 +2010,7 @@ void page_set_flags(target_ulong start, target_ulong end, int flags)
2002 2010 PageDesc *p;
2003 2011 target_ulong addr;
2004 2012  
  2013 + /* mmap_lock should already be held. */
2005 2014 start = start & TARGET_PAGE_MASK;
2006 2015 end = TARGET_PAGE_ALIGN(end);
2007 2016 if (flags & PAGE_WRITE)
... ... @@ -2065,11 +2074,18 @@ int page_unprotect(target_ulong address, unsigned long pc, void *puc)
2065 2074 PageDesc *p, *p1;
2066 2075 target_ulong host_start, host_end, addr;
2067 2076  
  2077 + /* Technically this isn't safe inside a signal handler. However we
  2078 + know this only ever happens in a synchronous SEGV handler, so in
  2079 + practice it seems to be ok. */
  2080 + mmap_lock();
  2081 +
2068 2082 host_start = address & qemu_host_page_mask;
2069 2083 page_index = host_start >> TARGET_PAGE_BITS;
2070 2084 p1 = page_find(page_index);
2071   - if (!p1)
  2085 + if (!p1) {
  2086 + mmap_unlock();
2072 2087 return 0;
  2088 + }
2073 2089 host_end = host_start + qemu_host_page_size;
2074 2090 p = p1;
2075 2091 prot = 0;
... ... @@ -2091,9 +2107,11 @@ int page_unprotect(target_ulong address, unsigned long pc, void *puc)
2091 2107 #ifdef DEBUG_TB_CHECK
2092 2108 tb_invalidate_check(address);
2093 2109 #endif
  2110 + mmap_unlock();
2094 2111 return 1;
2095 2112 }
2096 2113 }
  2114 + mmap_unlock();
2097 2115 return 0;
2098 2116 }
2099 2117  
... ...
linux-user/mmap.c
  View file @c8a706f
... ... @@ -29,6 +29,34 @@
29 29  
30 30 //#define DEBUG_MMAP
31 31  
  32 +#if defined(USE_NPTL)
  33 +pthread_mutex_t mmap_mutex;
  34 +static int __thread mmap_lock_count;
  35 +
  36 +void mmap_lock(void)
  37 +{
  38 + if (mmap_lock_count++ == 0) {
  39 + pthread_mutex_lock(&mmap_mutex);
  40 + }
  41 +}
  42 +
  43 +void mmap_unlock(void)
  44 +{
  45 + if (--mmap_lock_count == 0) {
  46 + pthread_mutex_unlock(&mmap_mutex);
  47 + }
  48 +}
  49 +#else
  50 +/* We aren't threadsafe to start with, so no need to worry about locking. */
  51 +void mmap_lock(void)
  52 +{
  53 +}
  54 +
  55 +void mmap_unlock(void)
  56 +{
  57 +}
  58 +#endif
  59 +
32 60 /* NOTE: all the constants are the HOST ones, but addresses are target. */
33 61 int target_mprotect(abi_ulong start, abi_ulong len, int prot)
34 62 {
... ... @@ -53,6 +81,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot)
53 81 if (len == 0)
54 82 return 0;
55 83  
  84 + mmap_lock();
56 85 host_start = start & qemu_host_page_mask;
57 86 host_end = HOST_PAGE_ALIGN(end);
58 87 if (start > host_start) {
... ... @@ -69,7 +98,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot)
69 98 }
70 99 ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
71 100 if (ret != 0)
72   - return ret;
  101 + goto error;
73 102 host_start += qemu_host_page_size;
74 103 }
75 104 if (end < host_end) {
... ... @@ -80,7 +109,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot)
80 109 ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
81 110 prot1 & PAGE_BITS);
82 111 if (ret != 0)
83   - return ret;
  112 + goto error;
84 113 host_end -= qemu_host_page_size;
85 114 }
86 115  
... ... @@ -88,10 +117,14 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot)
88 117 if (host_start < host_end) {
89 118 ret = mprotect(g2h(host_start), host_end - host_start, prot);
90 119 if (ret != 0)
91   - return ret;
  120 + goto error;
92 121 }
93 122 page_set_flags(start, start + len, prot | PAGE_VALID);
  123 + mmap_unlock();
94 124 return 0;
  125 +error:
  126 + mmap_unlock();
  127 + return ret;
95 128 }
96 129  
97 130 /* map an incomplete host page */
... ... @@ -214,6 +247,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
214 247 abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
215 248 unsigned long host_start;
216 249  
  250 + mmap_lock();
217 251 #ifdef DEBUG_MMAP
218 252 {
219 253 printf("mmap: start=0x" TARGET_FMT_lx
... ... @@ -243,12 +277,12 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
243 277  
244 278 if (offset & ~TARGET_PAGE_MASK) {
245 279 errno = EINVAL;
246   - return -1;
  280 + goto fail;
247 281 }
248 282  
249 283 len = TARGET_PAGE_ALIGN(len);
250 284 if (len == 0)
251   - return start;
  285 + goto the_end;
252 286 real_start = start & qemu_host_page_mask;
253 287  
254 288 if (!(flags & MAP_FIXED)) {
... ... @@ -260,7 +294,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
260 294 mmap_start = mmap_find_vma(real_start, host_len);
261 295 if (mmap_start == (abi_ulong)-1) {
262 296 errno = ENOMEM;
263   - return -1;
  297 + goto fail;
264 298 }
265 299 /* Note: we prefer to control the mapping address. It is
266 300 especially important if qemu_host_page_size >
... ... @@ -268,7 +302,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
268 302 p = mmap(g2h(mmap_start),
269 303 host_len, prot, flags | MAP_FIXED, fd, host_offset);
270 304 if (p == MAP_FAILED)
271   - return -1;
  305 + goto fail;
272 306 /* update start so that it points to the file position at 'offset' */
273 307 host_start = (unsigned long)p;
274 308 if (!(flags & MAP_ANONYMOUS))
... ... @@ -280,7 +314,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
280 314  
281 315 if (start & ~TARGET_PAGE_MASK) {
282 316 errno = EINVAL;
283   - return -1;
  317 + goto fail;
284 318 }
285 319 end = start + len;
286 320 real_end = HOST_PAGE_ALIGN(end);
... ... @@ -289,7 +323,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
289 323 flg = page_get_flags(addr);
290 324 if (flg & PAGE_RESERVED) {
291 325 errno = ENXIO;
292   - return -1;
  326 + goto fail;
293 327 }
294 328 }
295 329  
... ... @@ -302,18 +336,20 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
302 336 if ((flags & MAP_TYPE) == MAP_SHARED &&
303 337 (prot & PROT_WRITE)) {
304 338 errno = EINVAL;
305   - return -1;
  339 + goto fail;
306 340 }
307 341 retaddr = target_mmap(start, len, prot | PROT_WRITE,
308 342 MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
309 343 -1, 0);
310 344 if (retaddr == -1)
311   - return -1;
  345 + goto fail;
312 346 pread(fd, g2h(start), len, offset);
313 347 if (!(prot & PROT_WRITE)) {
314 348 ret = target_mprotect(start, len, prot);
315   - if (ret != 0)
316   - return ret;
  349 + if (ret != 0) {
  350 + start = ret;
  351 + goto the_end;
  352 + }
317 353 }
318 354 goto the_end;
319 355 }
... ... @@ -325,13 +361,13 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
325 361 ret = mmap_frag(real_start, start, end,
326 362 prot, flags, fd, offset);
327 363 if (ret == -1)
328   - return ret;
  364 + goto fail;
329 365 goto the_end1;
330 366 }
331 367 ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
332 368 prot, flags, fd, offset);
333 369 if (ret == -1)
334   - return ret;
  370 + goto fail;
335 371 real_start += qemu_host_page_size;
336 372 }
337 373 /* handle the end of the mapping */
... ... @@ -341,7 +377,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
341 377 prot, flags, fd,
342 378 offset + real_end - qemu_host_page_size - start);
343 379 if (ret == -1)
344   - return -1;
  380 + goto fail;
345 381 real_end -= qemu_host_page_size;
346 382 }
347 383  
... ... @@ -356,7 +392,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
356 392 p = mmap(g2h(real_start), real_end - real_start,
357 393 prot, flags, fd, offset1);
358 394 if (p == MAP_FAILED)
359   - return -1;
  395 + goto fail;
360 396 }
361 397 }
362 398 the_end1:
... ... @@ -367,7 +403,11 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
367 403 page_dump(stdout);
368 404 printf("\n");
369 405 #endif
  406 + mmap_unlock();
370 407 return start;
  408 +fail:
  409 + mmap_unlock();
  410 + return -1;
371 411 }
372 412  
373 413 int target_munmap(abi_ulong start, abi_ulong len)
... ... @@ -383,6 +423,7 @@ int target_munmap(abi_ulong start, abi_ulong len)
383 423 len = TARGET_PAGE_ALIGN(len);
384 424 if (len == 0)
385 425 return -EINVAL;
  426 + mmap_lock();
386 427 end = start + len;
387 428 real_start = start & qemu_host_page_mask;
388 429 real_end = HOST_PAGE_ALIGN(end);
... ... @@ -411,15 +452,16 @@ int target_munmap(abi_ulong start, abi_ulong len)
411 452 real_end -= qemu_host_page_size;
412 453 }
413 454  
  455 + ret = 0;
414 456 /* unmap what we can */
415 457 if (real_start < real_end) {
416 458 ret = munmap(g2h(real_start), real_end - real_start);
417   - if (ret != 0)
418   - return ret;
419 459 }
420 460  
421   - page_set_flags(start, start + len, 0);
422   - return 0;
  461 + if (ret == 0)
  462 + page_set_flags(start, start + len, 0);
  463 + mmap_unlock();
  464 + return ret;
423 465 }
424 466  
425 467 /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
... ... @@ -431,14 +473,18 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
431 473 int prot;
432 474 unsigned long host_addr;
433 475  
  476 + mmap_lock();
434 477 /* XXX: use 5 args syscall */
435 478 host_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags);
436   - if (host_addr == -1)
437   - return -1;
438   - new_addr = h2g(host_addr);
439   - prot = page_get_flags(old_addr);
440   - page_set_flags(old_addr, old_addr + old_size, 0);
441   - page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
  479 + if (host_addr == -1) {
  480 + new_addr = -1;
  481 + } else {
  482 + new_addr = h2g(host_addr);
  483 + prot = page_get_flags(old_addr);
  484 + page_set_flags(old_addr, old_addr + old_size, 0);
  485 + page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
  486 + }
  487 + mmap_unlock();
442 488 return new_addr;
443 489 }
444 490  
... ...
linux-user/qemu.h
  View file @c8a706f
... ... @@ -233,6 +233,8 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
233 233 abi_ulong new_addr);
234 234 int target_msync(abi_ulong start, abi_ulong len, int flags);
235 235 extern unsigned long last_brk;
  236 +void mmap_lock(void);
  237 +void mmap_unlock(void);
236 238  
237 239 /* user access */
238 240  
... ... @@ -423,4 +425,8 @@ static inline void *lock_user_string(abi_ulong guest_addr)
423 425 #define unlock_user_struct(host_ptr, guest_addr, copy) \
424 426 unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
425 427  
  428 +#if defined(USE_NPTL)
  429 +#include <pthread.h>
  430 +#endif
  431 +
426 432 #endif /* QEMU_H */
... ...