src/vm/jit/x86_64/patcher.c

   1 /* src/vm/jit/x86_64/patcher.c - x86_64 code patching functions
   2
   3    Copyright (C) 1996-2011
   4    CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO
   5
   6    This file is part of CACAO.
   7
   8    This program is free software; you can redistribute it and/or
   9    modify it under the terms of the GNU General Public License as
  10    published by the Free Software Foundation; either version 2, or (at
  11    your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful, but
  14    WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  21    02110-1301, USA.
  22
  23 */
  24
  25
  26 #include "config.h"
  27
  28 #include <stdint.h>
  29
  30 #include "vm/types.h"
  31
  32 #include "vm/jit/x86_64/codegen.h"
  33 #include "vm/jit/x86_64/md.h"
  34
  35 #include "mm/memory.hpp"
  36
  37 #include "native/native.hpp"
  38
  39 #include "vm/jit/builtin.hpp"
  40 #include "vm/class.hpp"
  41 #include "vm/field.hpp"
  42 #include "vm/initialize.hpp"
  43 #include "vm/options.h"
  44 #include "vm/references.h"
  45 #include "vm/resolve.hpp"
  46
  47 #include "vm/jit/patcher-common.hpp"
  48
  49
  50 /* patcher_patch_code **********************************************************
  51
  52    Just patches back the original machine code.
  53
  54 *******************************************************************************/
  55
  56 void patcher_patch_code(patchref_t *pr)
  57 {
  58         *((uint16_t*) pr->mpc) = (uint16_t) pr->mcode;
  59         md_icacheflush((void*) pr->mpc, PATCHER_CALL_SIZE);
  60 }
  61
  62 static int32_t *patch_checked_location(int32_t *p, int32_t val)
  63 {
  64         assert(*p == 0);
  65         // verify that it's aligned
  66         assert((((uintptr_t) p) & (4-1)) == 0);
  67         *p = val;
  68         return p;
  69 }
  70
  71 static void checked_icache_flush(int32_t *addr, int nbytes, int32_t *check_loc)
  72 {
  73         assert((int8_t*) addr + nbytes - sizeof(int32_t) >= (int8_t*) check_loc);
  74         md_icacheflush(addr, nbytes);
  75 }
  76
  77 /**
  78  * Check if the trap instruction at the given PC is valid.
  79  *
  80  * @param pc Program counter.
  81  *
  82  * @return true if valid, false otherwise.
  83  */
  84 bool patcher_is_valid_trap_instruction_at(void* pc)
  85 {
  86         uint16_t mcode = *((uint16_t*) pc);
  87
  88         // Check for the undefined instruction we use.
  89         return (mcode == 0x0b0f);
  90 }
  91
  92 /**
  93  * Overwrites the MFENCE instruction at the indicated address with a 3-byte
  94  * NOP. The MFENCE instruction is not allowed to cross a (4-byte) word
  95  * boundary.
  96  *
  97  * @param pc Program counter.
  98  */
  99 static void patch_out_mfence(void *pc)
 100 {
 101         uint32_t *p = (uint32_t*) (((uintptr_t) pc) & ~3);
 102
 103         assert((((uintptr_t) pc) & 3) < 2);
 104         if (((uintptr_t) pc) & 1)
 105                 *p = (*p & 0x000000ff) | 0x001f0f00;
 106         else
 107                 *p = (*p & 0xff000000) | 0x00001f0f;
 108
 109         md_icacheflush(p, 4);
 110 }
 111
 112 /* patcher_resolve_classref_to_classinfo ***************************************
 113
 114    ACONST:
 115
 116    <patched call position>
 117    48 bf a0 f0 92 00 00 00 00 00    mov    $0x92f0a0,%rdi
 118
 119    MULTIANEWARRAY:
 120
 121    <patched call position>
 122    48 be 30 40 b2 00 00 00 00 00    mov    $0xb24030,%rsi
 123    48 89 e2                         mov    %rsp,%rdx
 124    48 b8 7c 96 4b 00 00 00 00 00    mov    $0x4b967c,%rax
 125    48 ff d0                         callq  *%rax
 126
 127    ARRAYCHECKCAST:
 128
 129    <patched call position>
 130    48 be b8 3f b2 00 00 00 00 00    mov    $0xb23fb8,%rsi
 131    48 b8 00 00 00 00 00 00 00 00    mov    $0x0,%rax
 132    48 ff d0                         callq  *%rax
 133
 134 *******************************************************************************/
 135
 136 bool patcher_resolve_classref_to_classinfo(patchref_t *pr)
 137 {
 138         constant_classref* cr    = (constant_classref*) pr->ref;
 139         uintptr_t*         datap = (uintptr_t*)         pr->datap;
 140
 141         // Resolve the class.
 142         classinfo* c = resolve_classref_eager(cr);
 143
 144         if (c == NULL)
 145                 return false;
 146
 147         // Patch the class.
 148         *datap = (uintptr_t) c;
 149
 150         // Synchronize data cache.
 151         md_dcacheflush((void*) pr->datap, SIZEOF_VOID_P);
 152
 153         // Patch back the original code.
 154         patcher_patch_code(pr);
 155
 156         return true;
 157 }
 158
 159
 160 /* patcher_resolve_classref_to_vftbl *******************************************
 161
 162    CHECKCAST (class):
 163    INSTANCEOF (class):
 164
 165    <patched call position>
 166
 167 *******************************************************************************/
 168
 169 bool patcher_resolve_classref_to_vftbl(patchref_t *pr)
 170 {
 171         constant_classref* cr    = (constant_classref*) pr->ref;
 172         uintptr_t*         datap = (uintptr_t*)         pr->datap;
 173
 174         // Resolve the field.
 175         classinfo* c = resolve_classref_eager(cr);
 176
 177         if (c == NULL)
 178                 return false;
 179
 180         // Patch super class' vftbl.
 181         *datap = (uintptr_t) c->vftbl;
 182
 183         // Synchronize data cache.
 184         md_dcacheflush((void*) pr->datap, SIZEOF_VOID_P);
 185
 186         // Patch back the original code.
 187         patcher_patch_code(pr);
 188
 189         return true;
 190 }
 191
 192
 193 /* patcher_resolve_classref_to_flags *******************************************
 194
 195    CHECKCAST/INSTANCEOF:
 196
 197    <patched call position>
 198
 199 *******************************************************************************/
 200
 201 bool patcher_resolve_classref_to_flags(patchref_t *pr)
 202 {
 203         constant_classref* cr    = (constant_classref*) pr->ref;
 204 /*      int32_t*           datap = (int32_t*)           pr->datap; */
 205         uint8_t*           ra    = (uint8_t*)           pr->mpc;
 206
 207         // Resolve the field.
 208         classinfo* c = resolve_classref_eager(cr);
 209
 210         if (c == NULL)
 211                 return false;
 212
 213         ra += PATCHER_CALL_SIZE;
 214         ra += PATCH_ALIGNMENT((uintptr_t) ra, 2, sizeof(int32_t));
 215
 216         // Patch class flags.
 217 /*      *datap = c->flags; */
 218         patch_checked_location((int32_t*) (ra + 2), c->flags);
 219
 220         // Synchronize data cache.
 221 /*      md_dcacheflush(datap, sizeof(int32_t)); */
 222         md_icacheflush(ra + 2, sizeof(int32_t));
 223
 224         // Patch back the original code.
 225         patcher_patch_code(pr);
 226
 227         return true;
 228 }
 229
 230
 231 /* patcher_get_putstatic *******************************************************
 232
 233    Machine code:
 234
 235    <patched call position>
 236    4d 8b 15 86 fe ff ff             mov    -378(%rip),%r10
 237    49 8b 32                         mov    (%r10),%rsi
 238
 239 *******************************************************************************/
 240
 241 bool patcher_get_putstatic(patchref_t *pr)
 242 {
 243         unresolved_field* uf    = (unresolved_field*) pr->ref;
 244         uintptr_t*        datap = (uintptr_t*)        pr->datap;
 245         uint8_t*          ra    = (uint8_t*)          pr->mpc;
 246
 247         // Resolve the field.
 248         fieldinfo* fi = resolve_field_eager(uf);
 249
 250         if (fi == NULL)
 251                 return false;
 252
 253         ra += PATCHER_CALL_SIZE;
 254
 255         // Check if the field's class is initialized/
 256         if (!(fi->clazz->state & CLASS_INITIALIZED))
 257                 if (!initialize_class(fi->clazz))
 258                         return false;
 259
 260         // Patch the field value's address.
 261         *datap = (uintptr_t) fi->value;
 262
 263         if (pr->disp_mb && !(fi->flags & ACC_VOLATILE))
 264                 patch_out_mfence(ra + pr->disp_mb - 2);
 265
 266         // Synchronize data cache.
 267         md_dcacheflush((void*) pr->datap, SIZEOF_VOID_P);
 268
 269         // Patch back the original code.
 270         patcher_patch_code(pr);
 271
 272         return true;
 273 }
 274
 275
 276 /* patcher_get_putfield ********************************************************
 277
 278    Machine code:
 279
 280    <patched call position>
 281    45 8b 8f 00 00 00 00             mov    0x0(%r15),%r9d
 282
 283 *******************************************************************************/
 284
 285 bool patcher_get_putfield(patchref_t *pr)
 286 {
 287         uint8_t*          pc = (uint8_t*)          pr->mpc;
 288         unresolved_field* uf = (unresolved_field*) pr->ref;
 289
 290         // Resolve the field.
 291         fieldinfo* fi = resolve_field_eager(uf);
 292
 293         if (fi == NULL)
 294                 return false;
 295
 296         pc += PATCHER_CALL_SIZE;
 297
 298         int disp = -sizeof(int32_t) + pr->patch_align;
 299         patch_checked_location((int32_t*) (pc + disp), fi->offset);
 300
 301         if (pr->disp_mb && !(fi->flags & ACC_VOLATILE))
 302                 patch_out_mfence(pc + pr->disp_mb - 2);
 303
 304         // Synchronize instruction cache.
 305         md_icacheflush(pc, disp + sizeof(int32_t));
 306
 307         // Patch back the original code.
 308         patcher_patch_code(pr);
 309
 310         return true;
 311 }
 312
 313
 314 /* patcher_putfieldconst *******************************************************
 315
 316    Machine code:
 317
 318    <patched call position>
 319    41 c7 85 00 00 00 00 7b 00 00 00    movl   $0x7b,0x0(%r13)
 320
 321 *******************************************************************************/
 322
 323 bool patcher_putfieldconst(patchref_t *pr)
 324 {
 325         uint8_t*          pc = (uint8_t*)          pr->mpc;
 326         unresolved_field* uf = (unresolved_field*) pr->ref;
 327
 328         // Resolve the field.
 329         fieldinfo* fi = resolve_field_eager(uf);
 330
 331         if (fi == NULL)
 332                 return false;
 333
 334         pc += PATCHER_CALL_SIZE;
 335
 336         int disp = -2*sizeof(int32_t) + pr->patch_align;
 337         patch_checked_location((int32_t*) (pc + disp), fi->offset);
 338
 339         if (pr->disp_mb && !(fi->flags & ACC_VOLATILE))
 340                 patch_out_mfence(pc + pr->disp_mb - 2);
 341
 342         // Synchronize instruction cache.
 343         md_icacheflush(pc, disp + sizeof(int32_t));
 344
 345         // Patch back the original code.
 346         patcher_patch_code(pr);
 347
 348         return true;
 349 }
 350
 351
 352 /* patcher_invokestatic_special ************************************************
 353
 354    Machine code:
 355
 356    <patched call position>
 357    49 ba 00 00 00 00 00 00 00 00    mov    $0x0,%r10
 358    49 ff d2                         callq  *%r10
 359
 360 *******************************************************************************/
 361
 362 bool patcher_invokestatic_special(patchref_t *pr)
 363 {
 364         unresolved_method* um    = (unresolved_method*) pr->ref;
 365         uintptr_t*         datap = (uintptr_t*)         pr->datap;
 366
 367         // Resolve the method.
 368         methodinfo* m = resolve_method_eager(um);
 369
 370         if (m == NULL)
 371                 return false;
 372
 373         // Patch stubroutine.
 374         *datap = (uintptr_t) m->stubroutine;
 375
 376         // Synchronize data cache.
 377         md_dcacheflush((void*) pr->datap, SIZEOF_VOID_P);
 378
 379         // Patch back the original code.
 380         patcher_patch_code(pr);
 381
 382         return true;
 383 }
 384
 385
 386 /* patcher_invokevirtual *******************************************************
 387
 388    Machine code:
 389
 390    <patched call position>
 391    4c 8b 17                         mov    (%rdi),%r10
 392    49 8b 82 00 00 00 00             mov    0x0(%r10),%rax
 393    48 ff d0                         callq  *%rax
 394
 395 *******************************************************************************/
 396
 397 bool patcher_invokevirtual(patchref_t *pr)
 398 {
 399         uint8_t*           pc = (uint8_t*)           pr->mpc;
 400         unresolved_method* um = (unresolved_method*) pr->ref;
 401
 402         // Resovlve the method.
 403         methodinfo* m = resolve_method_eager(um);
 404
 405         if (m == NULL)
 406                 return false;
 407
 408         pc += PATCHER_CALL_SIZE;
 409         pc += PATCH_ALIGNMENT((uintptr_t) pc, 6, sizeof(int32_t));
 410
 411         // Patch vftbl index.
 412         patch_checked_location((int32_t*) (pc + 6), (int32_t) (OFFSET(vftbl_t, table[0]) + sizeof(methodptr) * m->vftblindex));
 413
 414         // Synchronize instruction cache.
 415         md_icacheflush(pc + 3 + 3, SIZEOF_VOID_P);
 416
 417         // Patch back the original code.
 418         patcher_patch_code(pr);
 419
 420         return true;
 421 }
 422
 423
 424 /* patcher_invokeinterface *****************************************************
 425
 426    Machine code:
 427
 428    <patched call position>
 429    4c 8b 17                         mov    (%rdi),%r10
 430    4d 8b 92 00 00 00 00             mov    0x0(%r10),%r10
 431    49 8b 82 00 00 00 00             mov    0x0(%r10),%rax
 432    48 ff d0                         callq  *%rax
 433
 434 *******************************************************************************/
 435
 436 bool patcher_invokeinterface(patchref_t *pr)
 437 {
 438         uint8_t*           pc = (uint8_t*)           pr->mpc;
 439         unresolved_method* um = (unresolved_method*) pr->ref;
 440
 441         // Resolve the method.
 442         methodinfo* m = resolve_method_eager(um);
 443
 444         if (m == NULL)
 445                 return false;
 446
 447         pc += PATCHER_CALL_SIZE;
 448         pc += PATCH_ALIGNMENT((uintptr_t) pc, 6, sizeof(int32_t));
 449
 450         // Patch interfacetable index.
 451         patch_checked_location((int32_t*) (pc + 6), (int32_t) (OFFSET(vftbl_t, interfacetable[0]) - sizeof(methodptr) * m->clazz->index));
 452
 453         int disp = PATCH_ALIGNMENT((uintptr_t) (pc + 3 + 7), 3, sizeof(int32_t));
 454         pc += disp;
 455         // Patch method offset.
 456         int32_t *loc = patch_checked_location((int32_t*) (pc + 3 + 7 + 3), (int32_t) (sizeof(methodptr) * (m - m->clazz->methods)));
 457
 458         // Synchronize instruction cache.
 459         checked_icache_flush(pc + 6, SIZEOF_VOID_P + 3 + SIZEOF_VOID_P + disp, loc);
 460
 461         // Patch back the original code.
 462         patcher_patch_code(pr);
 463
 464         return true;
 465 }
 466
 467
 468 /* patcher_checkcast_interface *************************************************
 469
 470    Machine code:
 471
 472    <patched call position>
 473    45 8b 9a 1c 00 00 00             mov    0x1c(%r10),%r11d
 474    41 81 fb 00 00 00 00             cmp    $0x0,%r11d
 475    0f 8f 08 00 00 00                jg     0x00002aaaaae511d5
 476    48 8b 0c 25 03 00 00 00          mov    0x3,%rcx
 477    4d 8b 9a 00 00 00 00             mov    0x0(%r10),%r11
 478
 479 *******************************************************************************/
 480
 481 bool patcher_checkcast_interface(patchref_t *pr)
 482 {
 483         uint8_t*           pc = (uint8_t*)           pr->mpc;
 484         constant_classref* cr = (constant_classref*) pr->ref;
 485
 486         // Resolve the class.
 487         classinfo* c = resolve_classref_eager(cr);
 488
 489         if (c == NULL)
 490                 return false;
 491
 492         pc += PATCHER_CALL_SIZE;
 493         pc += PATCH_ALIGNMENT((uintptr_t) pc, 10, sizeof(int32_t));
 494
 495         // Patch super class index.
 496         patch_checked_location((int32_t*) (pc + 10), c->index);
 497
 498         int disp = PATCH_ALIGNMENT((uintptr_t) (pc + 7 + 7 + 6 + 8), 3, sizeof(int32_t));
 499         pc += disp;
 500         int32_t *loc = patch_checked_location((int32_t*) (pc + 7 + 7 + 6 + 8 + 3), (int32_t) (OFFSET(vftbl_t, interfacetable[0]) - c->index * sizeof(methodptr*)));
 501
 502         // Synchronize instruction cache.
 503         checked_icache_flush(pc + 10, sizeof(int32_t) + 6 + 8 + 3 + sizeof(int32_t) + disp, loc);
 504
 505         // Patch back the original code.
 506         patcher_patch_code(pr);
 507
 508         return true;
 509 }
 510
 511
 512 /* patcher_instanceof_interface ************************************************
 513
 514    Machine code:
 515
 516    <patched call position>
 517    45 8b 9a 1c 00 00 00             mov    0x1c(%r10),%r11d
 518    41 81 fb 00 00 00 00             cmp    $0x0,%r11d
 519    0f 8e 94 04 00 00                jle    0x00002aaaaab018f8
 520    4d 8b 9a 00 00 00 00             mov    0x0(%r10),%r11
 521
 522 *******************************************************************************/
 523
 524 bool patcher_instanceof_interface(patchref_t *pr)
 525 {
 526         uint8_t*           pc = (uint8_t*)           pr->mpc;
 527         constant_classref* cr = (constant_classref*) pr->ref;
 528
 529         // Resolve the class.
 530         classinfo* c = resolve_classref_eager(cr);
 531
 532         if (c == NULL)
 533                 return false;
 534
 535         pc += PATCHER_CALL_SIZE;
 536         pc += PATCH_ALIGNMENT((uintptr_t) pc, 10, sizeof(int32_t));
 537
 538         // Patch super class index.
 539         patch_checked_location((int32_t*) (pc + 10), c->index);
 540
 541         int disp = PATCH_ALIGNMENT((uintptr_t) (pc + 7 + 7 + 6), 3, sizeof(int32_t));
 542         pc += disp;
 543         int32_t *loc = patch_checked_location((int32_t*) (pc + 7 + 7 + 6 + 3), (int32_t) (OFFSET(vftbl_t, interfacetable[0]) - c->index * sizeof(methodptr*)));
 544
 545         // Synchronize instruction cache.
 546         checked_icache_flush(pc + 10, sizeof(int32_t) + 6 + 3 + sizeof(int32_t) + disp, loc);
 547
 548         // Patch back the original code.
 549         patcher_patch_code(pr);
 550
 551         return true;
 552 }
 553
 554
 555 /*
 556  * These are local overrides for various environment variables in Emacs.
 557  * Please do not remove this and leave it at the end of the file, where
 558  * Emacs will automagically detect them.
 559  * ---------------------------------------------------------------------
 560  * Local variables:
 561  * mode: c
 562  * indent-tabs-mode: t
 563  * c-basic-offset: 4
 564  * tab-width: 4
 565  * End:
 566  * vim:noexpandtab:sw=4:ts=4:
 567  */