1 #ifdef USE_PRAGMA_IDENT_SRC 2 #pragma ident "@(#)os_solaris_x86.cpp 1.122 07/09/17 09:16:14 JVM" 3 #endif 4 /* 5 * Copyright 1999-2007 Sun Microsystems, Inc. All Rights Reserved. 6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 7 * 8 * This code is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License version 2 only, as 10 * published by the Free Software Foundation. 11 * 12 * This code is distributed in the hope that it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 * version 2 for more details (a copy is included in the LICENSE file that 16 * accompanied this code). 17 * 18 * You should have received a copy of the GNU General Public License version 19 * 2 along with this work; if not, write to the Free Software Foundation, 20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 21 * 22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 23 * CA 95054 USA or visit www.sun.com if you need additional information or 24 * have any questions. 25 * 26 */ 27 28 // do not include precompiled header file 29 # include "incls/_os_solaris_x86.cpp.incl" 30 31 // put OS-includes here 32 # include <sys/types.h> 33 # include <sys/mman.h> 34 # include <pthread.h> 35 # include <signal.h> 36 # include <setjmp.h> 37 # include <errno.h> 38 # include <dlfcn.h> 39 # include <stdio.h> 40 # include <unistd.h> 41 # include <sys/resource.h> 42 # include <thread.h> 43 # include <sys/stat.h> 44 # include <sys/time.h> 45 # include <sys/filio.h> 46 # include <sys/utsname.h> 47 # include <sys/systeminfo.h> 48 # include <sys/socket.h> 49 # include <sys/trap.h> 50 # include <sys/lwp.h> 51 # include <pwd.h> 52 # include <poll.h> 53 # include <sys/lwp.h> 54 # include <procfs.h> // see comment in <sys/procfs.h> 55 56 #ifndef AMD64 57 // QQQ seems useless at this point 58 # define _STRUCTURED_PROC 1 // this gets us the new structured proc interfaces of 5.6 & later 59 #endif // AMD64 60 # include <sys/procfs.h> // see comment in <sys/procfs.h> 61 62 63 #define MAX_PATH (2 * K) 64 65 // Minimum stack size for the VM. It's easier to document a constant value 66 // but it's different for x86 and sparc because the page sizes are different. 67 #ifdef AMD64 68 size_t os::Solaris::min_stack_allowed = 224*K; 69 #define REG_SP REG_RSP 70 #define REG_PC REG_RIP 71 #define REG_FP REG_RBP 72 #else 73 size_t os::Solaris::min_stack_allowed = 64*K; 74 #define REG_SP UESP 75 #define REG_PC EIP 76 #define REG_FP EBP 77 // 4900493 counter to prevent runaway LDTR refresh attempt 78 79 static volatile int ldtr_refresh = 0; 80 // the libthread instruction that faults because of the stale LDTR 81 82 static const unsigned char movlfs[] = { 0x8e, 0xe0 // movl %eax,%fs 83 }; 84 #endif // AMD64 85 86 char* os::non_memory_address_word() { 87 // Must never look like an address returned by reserve_memory, 88 // even in its subfields (as defined by the CPU immediate fields, 89 // if the CPU splits constants across multiple instructions). 90 return (char*) -1; 91 } 92 93 // 94 // Validate a ucontext retrieved from walking a uc_link of a ucontext. 95 // There are issues with libthread giving out uc_links for different threads 96 // on the same uc_link chain and bad or circular links. 97 // 98 bool os::Solaris::valid_ucontext(Thread* thread, ucontext_t* valid, ucontext_t* suspect) { 99 if (valid >= suspect || 100 valid->uc_stack.ss_flags != suspect->uc_stack.ss_flags || 101 valid->uc_stack.ss_sp != suspect->uc_stack.ss_sp || 102 valid->uc_stack.ss_size != suspect->uc_stack.ss_size) { 103 DEBUG_ONLY(tty->print_cr("valid_ucontext: failed test 1");) 104 return false; 105 } 106 107 if (thread->is_Java_thread()) { 108 if (!valid_stack_address(thread, (address)suspect)) { 109 DEBUG_ONLY(tty->print_cr("valid_ucontext: uc_link not in thread stack");) 110 return false; 111 } 112 if (!valid_stack_address(thread, (address) suspect->uc_mcontext.gregs[REG_SP])) { 113 DEBUG_ONLY(tty->print_cr("valid_ucontext: stackpointer not in thread stack");) 114 return false; 115 } 116 } 117 return true; 118 } 119 120 // We will only follow one level of uc_link since there are libthread 121 // issues with ucontext linking and it is better to be safe and just 122 // let caller retry later. 123 ucontext_t* os::Solaris::get_valid_uc_in_signal_handler(Thread *thread, 124 ucontext_t *uc) { 125 126 ucontext_t *retuc = NULL; 127 128 if (uc != NULL) { 129 if (uc->uc_link == NULL) { 130 // cannot validate without uc_link so accept current ucontext 131 retuc = uc; 132 } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) { 133 // first ucontext is valid so try the next one 134 uc = uc->uc_link; 135 if (uc->uc_link == NULL) { 136 // cannot validate without uc_link so accept current ucontext 137 retuc = uc; 138 } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) { 139 // the ucontext one level down is also valid so return it 140 retuc = uc; 141 } 142 } 143 } 144 return retuc; 145 } 146 147 // Assumes ucontext is valid 148 ExtendedPC os::Solaris::ucontext_get_ExtendedPC(ucontext_t *uc) { 149 return ExtendedPC((address)uc->uc_mcontext.gregs[REG_PC]); 150 } 151 152 // Assumes ucontext is valid 153 intptr_t* os::Solaris::ucontext_get_sp(ucontext_t *uc) { 154 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP]; 155 } 156 157 // Assumes ucontext is valid 158 intptr_t* os::Solaris::ucontext_get_fp(ucontext_t *uc) { 159 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP]; 160 } 161 162 // For Forte Analyzer AsyncGetCallTrace profiling support - thread 163 // is currently interrupted by SIGPROF. 164 // 165 // The difference between this and os::fetch_frame_from_context() is that 166 // here we try to skip nested signal frames. 167 ExtendedPC os::Solaris::fetch_frame_from_ucontext(Thread* thread, 168 ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) { 169 170 assert(thread != NULL, "just checking"); 171 assert(ret_sp != NULL, "just checking"); 172 assert(ret_fp != NULL, "just checking"); 173 174 ucontext_t *luc = os::Solaris::get_valid_uc_in_signal_handler(thread, uc); 175 return os::fetch_frame_from_context(luc, ret_sp, ret_fp); 176 } 177 178 ExtendedPC os::fetch_frame_from_context(void* ucVoid, 179 intptr_t** ret_sp, intptr_t** ret_fp) { 180 181 ExtendedPC epc; 182 ucontext_t *uc = (ucontext_t*)ucVoid; 183 184 if (uc != NULL) { 185 epc = os::Solaris::ucontext_get_ExtendedPC(uc); 186 if (ret_sp) *ret_sp = os::Solaris::ucontext_get_sp(uc); 187 if (ret_fp) *ret_fp = os::Solaris::ucontext_get_fp(uc); 188 } else { 189 // construct empty ExtendedPC for return value checking 190 epc = ExtendedPC(NULL); 191 if (ret_sp) *ret_sp = (intptr_t *)NULL; 192 if (ret_fp) *ret_fp = (intptr_t *)NULL; 193 } 194 195 return epc; 196 } 197 198 frame os::fetch_frame_from_context(void* ucVoid) { 199 intptr_t* sp; 200 intptr_t* fp; 201 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp); 202 return frame(sp, fp, epc.pc()); 203 } 204 205 frame os::get_sender_for_C_frame(frame* fr) { 206 return frame(fr->sender_sp(), fr->link(), fr->sender_pc()); 207 } 208 209 extern "C" intptr_t *_get_previous_fp(); // in .il file. 210 211 frame os::current_frame() { 212 intptr_t* fp = _get_previous_fp(); 213 frame myframe((intptr_t*)os::current_stack_pointer(), 214 (intptr_t*)fp, 215 CAST_FROM_FN_PTR(address, os::current_frame)); 216 if (os::is_first_C_frame(&myframe)) { 217 // stack is not walkable 218 return frame(NULL, NULL, NULL); 219 } else { 220 return os::get_sender_for_C_frame(&myframe); 221 } 222 } 223 224 // This is a simple callback that just fetches a PC for an interrupted thread. 225 // The thread need not be suspended and the fetched PC is just a hint. 226 // This one is currently used for profiling the VMThread ONLY! 227 228 // Must be synchronous 229 void GetThreadPC_Callback::execute(OSThread::InterruptArguments *args) { 230 Thread* thread = args->thread(); 231 ucontext_t* uc = args->ucontext(); 232 intptr_t* sp; 233 234 assert(ProfileVM && thread->is_VM_thread(), "just checking"); 235 236 ExtendedPC new_addr((address)uc->uc_mcontext.gregs[REG_PC]); 237 _addr = new_addr; 238 } 239 240 static int threadgetstate(thread_t tid, int *flags, lwpid_t *lwp, stack_t *ss, gregset_t rs, lwpstatus_t *lwpstatus) { 241 char lwpstatusfile[PROCFILE_LENGTH]; 242 int lwpfd, err; 243 244 if (err = os::Solaris::thr_getstate(tid, flags, lwp, ss, rs)) 245 return (err); 246 if (*flags == TRS_LWPID) { 247 sprintf(lwpstatusfile, "/proc/%d/lwp/%d/lwpstatus", getpid(), 248 *lwp); 249 if ((lwpfd = open(lwpstatusfile, O_RDONLY)) < 0) { 250 perror("thr_mutator_status: open lwpstatus"); 251 return (EINVAL); 252 } 253 if (pread(lwpfd, lwpstatus, sizeof (lwpstatus_t), (off_t)0) != 254 sizeof (lwpstatus_t)) { 255 perror("thr_mutator_status: read lwpstatus"); 256 (void) close(lwpfd); 257 return (EINVAL); 258 } 259 (void) close(lwpfd); 260 } 261 return (0); 262 } 263 264 #ifndef AMD64 265 266 // Detecting SSE support by OS 267 // From solaris_i486.s 268 extern "C" bool sse_check(); 269 extern "C" bool sse_unavailable(); 270 271 enum { SSE_UNKNOWN, SSE_NOT_SUPPORTED, SSE_SUPPORTED}; 272 static int sse_status = SSE_UNKNOWN; 273 274 275 static void check_for_sse_support() { 276 if (!VM_Version::supports_sse()) { 277 sse_status = SSE_NOT_SUPPORTED; 278 return; 279 } 280 // looking for _sse_hw in libc.so, if it does not exist or 281 // the value (int) is 0, OS has no support for SSE 282 int *sse_hwp; 283 void *h; 284 285 if ((h=dlopen("/usr/lib/libc.so", RTLD_LAZY)) == NULL) { 286 //open failed, presume no support for SSE 287 sse_status = SSE_NOT_SUPPORTED; 288 return; 289 } 290 if ((sse_hwp = (int *)dlsym(h, "_sse_hw")) == NULL) { 291 sse_status = SSE_NOT_SUPPORTED; 292 } else if (*sse_hwp == 0) { 293 sse_status = SSE_NOT_SUPPORTED; 294 } 295 dlclose(h); 296 297 if (sse_status == SSE_UNKNOWN) { 298 bool (*try_sse)() = (bool (*)())sse_check; 299 sse_status = (*try_sse)() ? SSE_SUPPORTED : SSE_NOT_SUPPORTED; 300 } 301 302 } 303 304 bool os::supports_sse() { 305 if (sse_status == SSE_UNKNOWN) 306 check_for_sse_support(); 307 return sse_status == SSE_SUPPORTED; 308 } 309 310 #endif // AMD64 311 312 bool os::is_allocatable(size_t bytes) { 313 #ifdef AMD64 314 return true; 315 #else 316 317 if (bytes < 2 * G) { 318 return true; 319 } 320 321 char* addr = reserve_memory(bytes, NULL); 322 323 if (addr != NULL) { 324 release_memory(addr, bytes); 325 } 326 327 return addr != NULL; 328 #endif // AMD64 329 330 } 331 332 extern "C" int JVM_handle_solaris_signal(int signo, siginfo_t* siginfo, void* ucontext, int abort_if_unrecognized); 333 334 extern "C" void Fetch32PFI () ; 335 extern "C" void Fetch32Resume () ; 336 #ifdef AMD64 337 extern "C" void FetchNPFI () ; 338 extern "C" void FetchNResume () ; 339 #endif // AMD64 340 341 int JVM_handle_solaris_signal(int sig, siginfo_t* info, void* ucVoid, int abort_if_unrecognized) { 342 ucontext_t* uc = (ucontext_t*) ucVoid; 343 344 #ifndef AMD64 345 if (sig == SIGILL && info->si_addr == (caddr_t)sse_check) { 346 // the SSE instruction faulted. supports_sse() need return false. 347 uc->uc_mcontext.gregs[EIP] = (greg_t)sse_unavailable; 348 return true; 349 } 350 #endif // !AMD64 351 352 Thread* t = ThreadLocalStorage::get_thread_slow(); // slow & steady 353 354 SignalHandlerMark shm(t); 355 356 if(sig == SIGPIPE || sig == SIGXFSZ) { 357 if (os::Solaris::chained_handler(sig, info, ucVoid)) { 358 return true; 359 } else { 360 if (PrintMiscellaneous && (WizardMode || Verbose)) { 361 char buf[64]; 362 warning("Ignoring %s - see 4229104 or 6499219", 363 os::exception_name(sig, buf, sizeof(buf))); 364 365 } 366 return true; 367 } 368 } 369 370 JavaThread* thread = NULL; 371 VMThread* vmthread = NULL; 372 373 if (os::Solaris::signal_handlers_are_installed) { 374 if (t != NULL ){ 375 if(t->is_Java_thread()) { 376 thread = (JavaThread*)t; 377 } 378 else if(t->is_VM_thread()){ 379 vmthread = (VMThread *)t; 380 } 381 } 382 } 383 384 guarantee(sig != os::Solaris::SIGinterrupt(), "Can not chain VM interrupt signal, try -XX:+UseAltSigs"); 385 386 if (sig == os::Solaris::SIGasync()) { 387 if(thread){ 388 OSThread::InterruptArguments args(thread, uc); 389 thread->osthread()->do_interrupt_callbacks_at_interrupt(&args); 390 return true; 391 } 392 else if(vmthread){ 393 OSThread::InterruptArguments args(vmthread, uc); 394 vmthread->osthread()->do_interrupt_callbacks_at_interrupt(&args); 395 return true; 396 } else if (os::Solaris::chained_handler(sig, info, ucVoid)) { 397 return true; 398 } else { 399 // If os::Solaris::SIGasync not chained, and this is a non-vm and 400 // non-java thread 401 return true; 402 } 403 } 404 405 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) { 406 // can't decode this kind of signal 407 info = NULL; 408 } else { 409 assert(sig == info->si_signo, "bad siginfo"); 410 } 411 412 // decide if this trap can be handled by a stub 413 address stub = NULL; 414 415 address pc = NULL; 416 417 //%note os_trap_1 418 if (info != NULL && uc != NULL && thread != NULL) { 419 // factor me: getPCfromContext 420 pc = (address) uc->uc_mcontext.gregs[REG_PC]; 421 422 // SafeFetch32() support 423 if (pc == (address) Fetch32PFI) { 424 uc->uc_mcontext.gregs[REG_PC] = intptr_t(Fetch32Resume) ; 425 return true ; 426 } 427 #ifdef AMD64 428 if (pc == (address) FetchNPFI) { 429 uc->uc_mcontext.gregs [REG_PC] = intptr_t(FetchNResume) ; 430 return true ; 431 } 432 #endif // AMD64 433 434 // Handle ALL stack overflow variations here 435 if (sig == SIGSEGV && info->si_code == SEGV_ACCERR) { 436 address addr = (address) info->si_addr; 437 if (thread->in_stack_yellow_zone(addr)) { 438 thread->disable_stack_yellow_zone(); 439 if (thread->thread_state() == _thread_in_Java) { 440 // Throw a stack overflow exception. Guard pages will be reenabled 441 // while unwinding the stack. 442 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW); 443 } else { 444 // Thread was in the vm or native code. Return and try to finish. 445 return true; 446 } 447 } else if (thread->in_stack_red_zone(addr)) { 448 // Fatal red zone violation. Disable the guard pages and fall through 449 // to handle_unexpected_exception way down below. 450 thread->disable_stack_red_zone(); 451 tty->print_raw_cr("An irrecoverable stack overflow has occurred."); 452 } 453 } 454 455 if (thread->thread_state() == _thread_in_vm) { 456 if (sig == SIGBUS && info->si_code == BUS_OBJERR && thread->doing_unsafe_access()) { 457 stub = StubRoutines::handler_for_unsafe_access(); 458 } 459 } 460 461 if (thread->thread_state() == _thread_in_Java) { 462 // Support Safepoint Polling 463 if ( sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) { 464 stub = SharedRuntime::get_poll_stub(pc); 465 } 466 else if (sig == SIGBUS && info->si_code == BUS_OBJERR) { 467 // BugId 4454115: A read from a MappedByteBuffer can fault 468 // here if the underlying file has been truncated. 469 // Do not crash the VM in such a case. 470 CodeBlob* cb = CodeCache::find_blob_unsafe(pc); 471 nmethod* nm = cb->is_nmethod() ? (nmethod*)cb : NULL; 472 if (nm != NULL && nm->has_unsafe_access()) { 473 stub = StubRoutines::handler_for_unsafe_access(); 474 } 475 } 476 else 477 if (sig == SIGFPE && info->si_code == FPE_INTDIV) { 478 // integer divide by zero 479 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); 480 } 481 #ifndef AMD64 482 else if (sig == SIGFPE && info->si_code == FPE_FLTDIV) { 483 // floating-point divide by zero 484 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); 485 } 486 else if (sig == SIGFPE && info->si_code == FPE_FLTINV) { 487 // The encoding of D2I in i486.ad can cause an exception prior 488 // to the fist instruction if there was an invalid operation 489 // pending. We want to dismiss that exception. From the win_32 490 // side it also seems that if it really was the fist causing 491 // the exception that we do the d2i by hand with different 492 // rounding. Seems kind of weird. QQQ TODO 493 // Note that we take the exception at the NEXT floating point instruction. 494 if (pc[0] == 0xDB) { 495 assert(pc[0] == 0xDB, "not a FIST opcode"); 496 assert(pc[1] == 0x14, "not a FIST opcode"); 497 assert(pc[2] == 0x24, "not a FIST opcode"); 498 return true; 499 } else { 500 assert(pc[-3] == 0xDB, "not an flt invalid opcode"); 501 assert(pc[-2] == 0x14, "not an flt invalid opcode"); 502 assert(pc[-1] == 0x24, "not an flt invalid opcode"); 503 } 504 } 505 else if (sig == SIGFPE ) { 506 tty->print_cr("caught SIGFPE, info 0x%x.", info->si_code); 507 } 508 #endif // !AMD64 509 510 // QQQ It doesn't seem that we need to do this on x86 because we should be able 511 // to return properly from the handler without this extra stuff on the back side. 512 513 else if (sig == SIGSEGV && info->si_code > 0 && !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) { 514 // Determination of interpreter/vtable stub/compiled code null exception 515 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); 516 } 517 } 518 519 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in 520 // and the heap gets shrunk before the field access. 521 if ((sig == SIGSEGV) || (sig == SIGBUS)) { 522 address addr = JNI_FastGetField::find_slowcase_pc(pc); 523 if (addr != (address)-1) { 524 stub = addr; 525 } 526 } 527 528 // Check to see if we caught the safepoint code in the 529 // process of write protecting the memory serialization page. 530 // It write enables the page immediately after protecting it 531 // so we can just return to retry the write. 532 if ((sig == SIGSEGV) && 533 os::is_memory_serialize_page(thread, (address)info->si_addr)) { 534 // Block current thread until the memory serialize page permission restored. 535 os::block_on_serialize_page_trap(); 536 return true; 537 } 538 } 539 540 // Execution protection violation 541 // 542 // Preventative code for future versions of Solaris which may 543 // enable execution protection when running the 32-bit VM on AMD64. 544 // 545 // This should be kept as the last step in the triage. We don't 546 // have a dedicated trap number for a no-execute fault, so be 547 // conservative and allow other handlers the first shot. 548 // 549 // Note: We don't test that info->si_code == SEGV_ACCERR here. 550 // this si_code is so generic that it is almost meaningless; and 551 // the si_code for this condition may change in the future. 552 // Furthermore, a false-positive should be harmless. 553 if (UnguardOnExecutionViolation > 0 && 554 (sig == SIGSEGV || sig == SIGBUS) && 555 uc->uc_mcontext.gregs[TRAPNO] == T_PGFLT) { // page fault 556 int page_size = os::vm_page_size(); 557 address addr = (address) info->si_addr; 558 address pc = (address) uc->uc_mcontext.gregs[REG_PC]; 559 // Make sure the pc and the faulting address are sane. 560 // 561 // If an instruction spans a page boundary, and the page containing 562 // the beginning of the instruction is executable but the following 563 // page is not, the pc and the faulting address might be slightly 564 // different - we still want to unguard the 2nd page in this case. 565 // 566 // 15 bytes seems to be a (very) safe value for max instruction size. 567 bool pc_is_near_addr = 568 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15); 569 bool instr_spans_page_boundary = 570 (align_size_down((intptr_t) pc ^ (intptr_t) addr, 571 (intptr_t) page_size) > 0); 572 573 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) { 574 static volatile address last_addr = 575 (address) os::non_memory_address_word(); 576 577 // In conservative mode, don't unguard unless the address is in the VM 578 if (addr != last_addr && 579 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) { 580 581 // Unguard and retry 582 address page_start = 583 (address) align_size_down((intptr_t) addr, (intptr_t) page_size); 584 bool res = os::unguard_memory((char*) page_start, page_size); 585 586 if (PrintMiscellaneous && Verbose) { 587 char buf[256]; 588 jio_snprintf(buf, sizeof(buf), "Execution protection violation " 589 "at " INTPTR_FORMAT 590 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr, 591 page_start, (res ? "success" : "failed"), errno); 592 tty->print_raw_cr(buf); 593 } 594 stub = pc; 595 596 // Set last_addr so if we fault again at the same address, we don't end 597 // up in an endless loop. 598 // 599 // There are two potential complications here. Two threads trapping at 600 // the same address at the same time could cause one of the threads to 601 // think it already unguarded, and abort the VM. Likely very rare. 602 // 603 // The other race involves two threads alternately trapping at 604 // different addresses and failing to unguard the page, resulting in 605 // an endless loop. This condition is probably even more unlikely than 606 // the first. 607 // 608 // Although both cases could be avoided by using locks or thread local 609 // last_addr, these solutions are unnecessary complication: this 610 // handler is a best-effort safety net, not a complete solution. It is 611 // disabled by default and should only be used as a workaround in case 612 // we missed any no-execute-unsafe VM code. 613 614 last_addr = addr; 615 } 616 } 617 } 618 619 if (stub != NULL) { 620 // save all thread context in case we need to restore it 621 622 if (thread != NULL) thread->set_saved_exception_pc(pc); 623 // 12/02/99: On Sparc it appears that the full context is also saved 624 // but as yet, no one looks at or restores that saved context 625 // factor me: setPC 626 uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub; 627 return true; 628 } 629 630 // signal-chaining 631 if (os::Solaris::chained_handler(sig, info, ucVoid)) { 632 return true; 633 } 634 635 #ifndef AMD64 636 // Workaround (bug 4900493) for Solaris kernel bug 4966651. 637 // Handle an undefined selector caused by an attempt to assign 638 // fs in libthread getipriptr(). With the current libthread design every 512 639 // thread creations the LDT for a private thread data structure is extended 640 // and thre is a hazard that and another thread attempting a thread creation 641 // will use a stale LDTR that doesn't reflect the structure's growth, 642 // causing a GP fault. 643 // Enforce the probable limit of passes through here to guard against an 644 // infinite loop if some other move to fs caused the GP fault. Note that 645 // this loop counter is ultimately a heuristic as it is possible for 646 // more than one thread to generate this fault at a time in an MP system. 647 // In the case of the loop count being exceeded or if the poll fails 648 // just fall through to a fatal error. 649 // If there is some other source of T_GPFLT traps and the text at EIP is 650 // unreadable this code will loop infinitely until the stack is exausted. 651 // The key to diagnosis in this case is to look for the bottom signal handler 652 // frame. 653 654 if(! IgnoreLibthreadGPFault) { 655 if (sig == SIGSEGV && uc->uc_mcontext.gregs[TRAPNO] == T_GPFLT) { 656 const unsigned char *p = 657 (unsigned const char *) uc->uc_mcontext.gregs[EIP]; 658 659 // Expected instruction? 660 661 if(p[0] == movlfs[0] && p[1] == movlfs[1]) { 662 663 Atomic::inc(&ldtr_refresh); 664 665 // Infinite loop? 666 667 if(ldtr_refresh < ((2 << 16) / PAGESIZE)) { 668 669 // No, force scheduling to get a fresh view of the LDTR 670 671 if(poll(NULL, 0, 10) == 0) { 672 673 // Retry the move 674 675 return false; 676 } 677 } 678 } 679 } 680 } 681 #endif // !AMD64 682 683 if (!abort_if_unrecognized) { 684 // caller wants another chance, so give it to him 685 return false; 686 } 687 688 if (!os::Solaris::libjsig_is_loaded) { 689 struct sigaction oldAct; 690 sigaction(sig, (struct sigaction *)0, &oldAct); 691 if (oldAct.sa_sigaction != signalHandler) { 692 void* sighand = oldAct.sa_sigaction ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 693 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 694 warning("Unexpected Signal %d occured under user-defined signal handler %#lx", sig, (long)sighand); 695 } 696 } 697 698 if (pc == NULL && uc != NULL) { 699 pc = (address) uc->uc_mcontext.gregs[REG_PC]; 700 } 701 702 // unmask current signal 703 sigset_t newset; 704 sigemptyset(&newset); 705 sigaddset(&newset, sig); 706 sigprocmask(SIG_UNBLOCK, &newset, NULL); 707 708 VMError err(t, sig, pc, info, ucVoid); 709 err.report_and_die(); 710 711 ShouldNotReachHere(); 712 } 713 714 void os::print_context(outputStream *st, void *context) { 715 if (context == NULL) return; 716 717 ucontext_t *uc = (ucontext_t*)context; 718 st->print_cr("Registers:"); 719 #ifdef AMD64 720 st->print( "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]); 721 st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]); 722 st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]); 723 st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]); 724 st->cr(); 725 st->print( "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]); 726 st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]); 727 st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]); 728 st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]); 729 st->cr(); 730 st->print(", R8=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]); 731 st->print(", R9=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]); 732 st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]); 733 st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]); 734 st->print(", R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]); 735 st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]); 736 st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]); 737 st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]); 738 st->cr(); 739 st->print( "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]); 740 st->print(", RFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RFL]); 741 #else 742 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EAX]); 743 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBX]); 744 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ECX]); 745 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDX]); 746 st->cr(); 747 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[UESP]); 748 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBP]); 749 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ESI]); 750 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDI]); 751 st->cr(); 752 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EIP]); 753 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EFL]); 754 #endif // AMD64 755 st->cr(); 756 st->cr(); 757 758 intptr_t *sp = (intptr_t *)os::Solaris::ucontext_get_sp(uc); 759 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp); 760 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t)); 761 st->cr(); 762 763 // Note: it may be unsafe to inspect memory near pc. For example, pc may 764 // point to garbage if entry point in an nmethod is corrupted. Leave 765 // this at the end, and hope for the best. 766 ExtendedPC epc = os::Solaris::ucontext_get_ExtendedPC(uc); 767 address pc = epc.pc(); 768 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc); 769 print_hex_dump(st, pc - 16, pc + 16, sizeof(char)); 770 } 771 772 #ifdef AMD64 773 void os::Solaris::init_thread_fpu_state(void) { 774 // Nothing to do 775 } 776 #else 777 // From solaris_i486.s 778 extern "C" void fixcw(); 779 780 void os::Solaris::init_thread_fpu_state(void) { 781 // Set fpu to 53 bit precision. This happens too early to use a stub. 782 fixcw(); 783 } 784 785 // These routines are the initial value of atomic_xchg_entry(), 786 // atomic_cmpxchg_entry(), atomic_inc_entry() and fence_entry() 787 // until initialization is complete. 788 // TODO - replace with .il implementation when compiler supports it. 789 790 typedef jint xchg_func_t (jint, volatile jint*); 791 typedef jint cmpxchg_func_t (jint, volatile jint*, jint); 792 typedef jlong cmpxchg_long_func_t(jlong, volatile jlong*, jlong); 793 typedef jint add_func_t (jint, volatile jint*); 794 typedef void fence_func_t (); 795 796 jint os::atomic_xchg_bootstrap(jint exchange_value, volatile jint* dest) { 797 // try to use the stub: 798 xchg_func_t* func = CAST_TO_FN_PTR(xchg_func_t*, StubRoutines::atomic_xchg_entry()); 799 800 if (func != NULL) { 801 os::atomic_xchg_func = func; 802 return (*func)(exchange_value, dest); 803 } 804 assert(Threads::number_of_threads() == 0, "for bootstrap only"); 805 806 jint old_value = *dest; 807 *dest = exchange_value; 808 return old_value; 809 } 810 811 jint os::atomic_cmpxchg_bootstrap(jint exchange_value, volatile jint* dest, jint compare_value) { 812 // try to use the stub: 813 cmpxchg_func_t* func = CAST_TO_FN_PTR(cmpxchg_func_t*, StubRoutines::atomic_cmpxchg_entry()); 814 815 if (func != NULL) { 816 os::atomic_cmpxchg_func = func; 817 return (*func)(exchange_value, dest, compare_value); 818 } 819 assert(Threads::number_of_threads() == 0, "for bootstrap only"); 820 821 jint old_value = *dest; 822 if (old_value == compare_value) 823 *dest = exchange_value; 824 return old_value; 825 } 826 827 jlong os::atomic_cmpxchg_long_bootstrap(jlong exchange_value, volatile jlong* dest, jlong compare_value) { 828 // try to use the stub: 829 cmpxchg_long_func_t* func = CAST_TO_FN_PTR(cmpxchg_long_func_t*, StubRoutines::atomic_cmpxchg_long_entry()); 830 831 if (func != NULL) { 832 os::atomic_cmpxchg_long_func = func; 833 return (*func)(exchange_value, dest, compare_value); 834 } 835 assert(Threads::number_of_threads() == 0, "for bootstrap only"); 836 837 jlong old_value = *dest; 838 if (old_value == compare_value) 839 *dest = exchange_value; 840 return old_value; 841 } 842 843 jint os::atomic_add_bootstrap(jint add_value, volatile jint* dest) { 844 // try to use the stub: 845 add_func_t* func = CAST_TO_FN_PTR(add_func_t*, StubRoutines::atomic_add_entry()); 846 847 if (func != NULL) { 848 os::atomic_add_func = func; 849 return (*func)(add_value, dest); 850 } 851 assert(Threads::number_of_threads() == 0, "for bootstrap only"); 852 853 return (*dest) += add_value; 854 } 855 856 void os::fence_bootstrap() { 857 // try to use the stub: 858 fence_func_t* func = CAST_TO_FN_PTR(fence_func_t*, StubRoutines::fence_entry()); 859 860 if (func != NULL) { 861 os::fence_func = func; 862 (*func)(); 863 return; 864 } 865 assert(Threads::number_of_threads() == 0, "for bootstrap only"); 866 867 // don't have to do anything for a single thread 868 } 869 870 xchg_func_t* os::atomic_xchg_func = os::atomic_xchg_bootstrap; 871 cmpxchg_func_t* os::atomic_cmpxchg_func = os::atomic_cmpxchg_bootstrap; 872 cmpxchg_long_func_t* os::atomic_cmpxchg_long_func = os::atomic_cmpxchg_long_bootstrap; 873 add_func_t* os::atomic_add_func = os::atomic_add_bootstrap; 874 fence_func_t* os::fence_func = os::fence_bootstrap; 875 876 extern "C" _solaris_raw_setup_fpu(address ptr); 877 void os::setup_fpu() { 878 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std(); 879 _solaris_raw_setup_fpu(fpu_cntrl); 880 } 881 #endif // AMD64 882