1 /* 2 * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "asm/macroAssembler.hpp" 27 #include "classfile/classLoader.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/icBuffer.hpp" 31 #include "code/vtableStubs.hpp" 32 #include "interpreter/interpreter.hpp" 33 #include "jvm_linux.h" 34 #include "memory/allocation.inline.hpp" 35 #include "mutex_linux.inline.hpp" 36 #include "os_share_linux.hpp" 37 #include "prims/jniFastGetField.hpp" 38 #include "prims/jvm.h" 39 #include "prims/jvm_misc.hpp" 40 #include "runtime/arguments.hpp" 41 #include "runtime/extendedPC.hpp" 42 #include "runtime/frame.inline.hpp" 43 #include "runtime/interfaceSupport.hpp" 44 #include "runtime/java.hpp" 45 #include "runtime/javaCalls.hpp" 46 #include "runtime/mutexLocker.hpp" 47 #include "runtime/osThread.hpp" 48 #include "runtime/sharedRuntime.hpp" 49 #include "runtime/stubRoutines.hpp" 50 #include "runtime/thread.inline.hpp" 51 #include "runtime/timer.hpp" 52 #include "services/memTracker.hpp" 53 #include "utilities/events.hpp" 54 #include "utilities/vmError.hpp" 55 56 // put OS-includes here 57 # include <sys/types.h> 58 # include <sys/mman.h> 59 # include <pthread.h> 60 # include <signal.h> 61 # include <errno.h> 62 # include <dlfcn.h> 63 # include <stdlib.h> 64 # include <stdio.h> 65 # include <unistd.h> 66 # include <sys/resource.h> 67 # include <pthread.h> 68 # include <sys/stat.h> 69 # include <sys/time.h> 70 # include <sys/utsname.h> 71 # include <sys/socket.h> 72 # include <sys/wait.h> 73 # include <pwd.h> 74 # include <poll.h> 75 # include <ucontext.h> 76 # include <fpu_control.h> 77 78 #ifdef AMD64 79 #define REG_SP REG_RSP 80 #define REG_PC REG_RIP 81 #define REG_FP REG_RBP 82 #define SPELL_REG_SP "rsp" 83 #define SPELL_REG_FP "rbp" 84 #else 85 #define REG_SP REG_UESP 86 #define REG_PC REG_EIP 87 #define REG_FP REG_EBP 88 #define SPELL_REG_SP "esp" 89 #define SPELL_REG_FP "ebp" 90 #endif // AMD64 91 92 address os::current_stack_pointer() { 93 #ifdef SPARC_WORKS 94 register void *esp; 95 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp)); 96 return (address) ((char*)esp + sizeof(long)*2); 97 #elif defined(__clang__) 98 intptr_t* esp; 99 __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):); 100 return (address) esp; 101 #else 102 register void *esp __asm__ (SPELL_REG_SP); 103 return (address) esp; 104 #endif 105 } 106 107 char* os::non_memory_address_word() { 108 // Must never look like an address returned by reserve_memory, 109 // even in its subfields (as defined by the CPU immediate fields, 110 // if the CPU splits constants across multiple instructions). 111 112 return (char*) -1; 113 } 114 115 void os::initialize_thread(Thread* thr) { 116 // Nothing to do. 117 } 118 119 address os::Linux::ucontext_get_pc(ucontext_t * uc) { 120 return (address)uc->uc_mcontext.gregs[REG_PC]; 121 } 122 123 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) { 124 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc; 125 } 126 127 intptr_t* os::Linux::ucontext_get_sp(ucontext_t * uc) { 128 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP]; 129 } 130 131 intptr_t* os::Linux::ucontext_get_fp(ucontext_t * uc) { 132 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP]; 133 } 134 135 // For Forte Analyzer AsyncGetCallTrace profiling support - thread 136 // is currently interrupted by SIGPROF. 137 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal 138 // frames. Currently we don't do that on Linux, so it's the same as 139 // os::fetch_frame_from_context(). 140 // This method is also used for stack overflow signal handling. 141 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread, 142 ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) { 143 144 assert(thread != NULL, "just checking"); 145 assert(ret_sp != NULL, "just checking"); 146 assert(ret_fp != NULL, "just checking"); 147 148 return os::fetch_frame_from_context(uc, ret_sp, ret_fp); 149 } 150 151 ExtendedPC os::fetch_frame_from_context(void* ucVoid, 152 intptr_t** ret_sp, intptr_t** ret_fp) { 153 154 ExtendedPC epc; 155 ucontext_t* uc = (ucontext_t*)ucVoid; 156 157 if (uc != NULL) { 158 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc)); 159 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc); 160 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc); 161 } else { 162 // construct empty ExtendedPC for return value checking 163 epc = ExtendedPC(NULL); 164 if (ret_sp) *ret_sp = (intptr_t *)NULL; 165 if (ret_fp) *ret_fp = (intptr_t *)NULL; 166 } 167 168 return epc; 169 } 170 171 frame os::fetch_frame_from_context(void* ucVoid) { 172 intptr_t* sp; 173 intptr_t* fp; 174 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp); 175 return frame(sp, fp, epc.pc()); 176 } 177 178 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) { 179 intptr_t* sp; 180 intptr_t* fp; 181 ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp); 182 return frame(sp, fp, epc.pc()); 183 } 184 185 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) { 186 address pc = (address) os::Linux::ucontext_get_pc(uc); 187 if (Interpreter::contains(pc)) { 188 // interpreter performs stack banging after the fixed frame header has 189 // been generated while the compilers perform it before. To maintain 190 // semantic consistency between interpreted and compiled frames, the 191 // method returns the Java sender of the current frame. 192 *fr = os::fetch_frame_from_ucontext(thread, uc); 193 if (!fr->is_first_java_frame()) { 194 assert(fr->safe_for_sender(thread), "Safety check"); 195 *fr = fr->java_sender(); 196 } 197 } else { 198 // more complex code with compiled code 199 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above"); 200 CodeBlob* cb = CodeCache::find_blob(pc); 201 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) { 202 // Not sure where the pc points to, fallback to default 203 // stack overflow handling 204 return false; 205 } else { 206 // in compiled code, the stack banging is performed just after the return pc 207 // has been pushed on the stack 208 intptr_t* fp = os::Linux::ucontext_get_fp(uc); 209 intptr_t* sp = os::Linux::ucontext_get_sp(uc); 210 *fr = frame(sp + 1, fp, (address)*sp); 211 if (!fr->is_java_frame()) { 212 assert(fr->safe_for_sender(thread), "Safety check"); 213 assert(!fr->is_first_frame(), "Safety check"); 214 *fr = fr->java_sender(); 215 } 216 } 217 } 218 assert(fr->is_java_frame(), "Safety check"); 219 return true; 220 } 221 222 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get 223 // turned off by -fomit-frame-pointer, 224 frame os::get_sender_for_C_frame(frame* fr) { 225 return frame(fr->sender_sp(), fr->link(), fr->sender_pc()); 226 } 227 228 intptr_t* _get_previous_fp() { 229 #ifdef SPARC_WORKS 230 register intptr_t **ebp; 231 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp)); 232 #elif defined(__clang__) 233 intptr_t **ebp; 234 __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):); 235 #else 236 register intptr_t **ebp __asm__ (SPELL_REG_FP); 237 #endif 238 return (intptr_t*) *ebp; // we want what it points to. 239 } 240 241 242 frame os::current_frame() { 243 intptr_t* fp = _get_previous_fp(); 244 frame myframe((intptr_t*)os::current_stack_pointer(), 245 (intptr_t*)fp, 246 CAST_FROM_FN_PTR(address, os::current_frame)); 247 if (os::is_first_C_frame(&myframe)) { 248 // stack is not walkable 249 return frame(); 250 } else { 251 return os::get_sender_for_C_frame(&myframe); 252 } 253 } 254 255 // Utility functions 256 257 // From IA32 System Programming Guide 258 enum { 259 trap_page_fault = 0xE 260 }; 261 262 extern "C" JNIEXPORT int 263 JVM_handle_linux_signal(int sig, 264 siginfo_t* info, 265 void* ucVoid, 266 int abort_if_unrecognized) { 267 ucontext_t* uc = (ucontext_t*) ucVoid; 268 269 Thread* t = ThreadLocalStorage::get_thread_slow(); 270 271 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away 272 // (no destructors can be run) 273 os::WatcherThreadCrashProtection::check_crash_protection(sig, t); 274 275 SignalHandlerMark shm(t); 276 277 // Note: it's not uncommon that JNI code uses signal/sigset to install 278 // then restore certain signal handler (e.g. to temporarily block SIGPIPE, 279 // or have a SIGILL handler when detecting CPU type). When that happens, 280 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To 281 // avoid unnecessary crash when libjsig is not preloaded, try handle signals 282 // that do not require siginfo/ucontext first. 283 284 if (sig == SIGPIPE || sig == SIGXFSZ) { 285 // allow chained handler to go first 286 if (os::Linux::chained_handler(sig, info, ucVoid)) { 287 return true; 288 } else { 289 if (PrintMiscellaneous && (WizardMode || Verbose)) { 290 char buf[64]; 291 warning("Ignoring %s - see bugs 4229104 or 646499219", 292 os::exception_name(sig, buf, sizeof(buf))); 293 } 294 return true; 295 } 296 } 297 298 JavaThread* thread = NULL; 299 VMThread* vmthread = NULL; 300 if (os::Linux::signal_handlers_are_installed) { 301 if (t != NULL ){ 302 if(t->is_Java_thread()) { 303 thread = (JavaThread*)t; 304 } 305 else if(t->is_VM_thread()){ 306 vmthread = (VMThread *)t; 307 } 308 } 309 } 310 /* 311 NOTE: does not seem to work on linux. 312 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) { 313 // can't decode this kind of signal 314 info = NULL; 315 } else { 316 assert(sig == info->si_signo, "bad siginfo"); 317 } 318 */ 319 // decide if this trap can be handled by a stub 320 address stub = NULL; 321 322 address pc = NULL; 323 324 //%note os_trap_1 325 if (info != NULL && uc != NULL && thread != NULL) { 326 pc = (address) os::Linux::ucontext_get_pc(uc); 327 328 if (StubRoutines::is_safefetch_fault(pc)) { 329 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc)); 330 return 1; 331 } 332 333 #ifndef AMD64 334 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs 335 // This can happen in any running code (currently more frequently in 336 // interpreter code but has been seen in compiled code) 337 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) { 338 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due " 339 "to unstable signal handling in this distribution."); 340 } 341 #endif // AMD64 342 343 // Handle ALL stack overflow variations here 344 if (sig == SIGSEGV) { 345 address addr = (address) info->si_addr; 346 347 // check if fault address is within thread stack 348 if (addr < thread->stack_base() && 349 addr >= thread->stack_base() - thread->stack_size()) { 350 // stack overflow 351 if (thread->in_stack_yellow_zone(addr)) { 352 if (thread->thread_state() == _thread_in_Java) { 353 if (thread->in_stack_reserved_zone(addr)) { 354 frame fr; 355 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) { 356 assert(fr.is_java_frame(), "Must be a Java frame"); 357 frame activation = 358 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr); 359 if (activation.sp() != NULL) { 360 thread->disable_stack_reserved_zone(); 361 if (activation.is_interpreted_frame()) { 362 thread->set_reserved_stack_activation((address)( 363 activation.fp() + frame::interpreter_frame_initial_sp_offset)); 364 } else { 365 thread->set_reserved_stack_activation((address)activation.unextended_sp()); 366 } 367 return 1; 368 } 369 } 370 } 371 // Throw a stack overflow exception. Guard pages will be reenabled 372 // while unwinding the stack. 373 thread->disable_stack_yellow_zone(); 374 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW); 375 } else { 376 // Thread was in the vm or native code. Return and try to finish. 377 thread->disable_stack_yellow_zone(); 378 return 1; 379 } 380 } else if (thread->in_stack_red_zone(addr)) { 381 // Fatal red zone violation. Disable the guard pages and fall through 382 // to handle_unexpected_exception way down below. 383 thread->disable_stack_red_zone(); 384 tty->print_raw_cr("An irrecoverable stack overflow has occurred."); 385 386 // This is a likely cause, but hard to verify. Let's just print 387 // it as a hint. 388 tty->print_raw_cr("Please check if any of your loaded .so files has " 389 "enabled executable stack (see man page execstack(8))"); 390 } else { 391 // Accessing stack address below sp may cause SEGV if current 392 // thread has MAP_GROWSDOWN stack. This should only happen when 393 // current thread was created by user code with MAP_GROWSDOWN flag 394 // and then attached to VM. See notes in os_linux.cpp. 395 if (thread->osthread()->expanding_stack() == 0) { 396 thread->osthread()->set_expanding_stack(); 397 if (os::Linux::manually_expand_stack(thread, addr)) { 398 thread->osthread()->clear_expanding_stack(); 399 return 1; 400 } 401 thread->osthread()->clear_expanding_stack(); 402 } else { 403 fatal("recursive segv. expanding stack."); 404 } 405 } 406 } 407 } 408 409 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) { 410 // Verify that OS save/restore AVX registers. 411 stub = VM_Version::cpuinfo_cont_addr(); 412 } 413 414 if (thread->thread_state() == _thread_in_Java) { 415 // Java thread running in Java code => find exception handler if any 416 // a fault inside compiled code, the interpreter, or a stub 417 418 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) { 419 stub = SharedRuntime::get_poll_stub(pc); 420 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) { 421 // BugId 4454115: A read from a MappedByteBuffer can fault 422 // here if the underlying file has been truncated. 423 // Do not crash the VM in such a case. 424 CodeBlob* cb = CodeCache::find_blob_unsafe(pc); 425 nmethod* nm = (cb != NULL && cb->is_nmethod()) ? (nmethod*)cb : NULL; 426 if (nm != NULL && nm->has_unsafe_access()) { 427 stub = StubRoutines::handler_for_unsafe_access(); 428 } 429 } 430 else 431 432 #ifdef AMD64 433 if (sig == SIGFPE && 434 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) { 435 stub = 436 SharedRuntime:: 437 continuation_for_implicit_exception(thread, 438 pc, 439 SharedRuntime:: 440 IMPLICIT_DIVIDE_BY_ZERO); 441 #else 442 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) { 443 // HACK: si_code does not work on linux 2.2.12-20!!! 444 int op = pc[0]; 445 if (op == 0xDB) { 446 // FIST 447 // TODO: The encoding of D2I in i486.ad can cause an exception 448 // prior to the fist instruction if there was an invalid operation 449 // pending. We want to dismiss that exception. From the win_32 450 // side it also seems that if it really was the fist causing 451 // the exception that we do the d2i by hand with different 452 // rounding. Seems kind of weird. 453 // NOTE: that we take the exception at the NEXT floating point instruction. 454 assert(pc[0] == 0xDB, "not a FIST opcode"); 455 assert(pc[1] == 0x14, "not a FIST opcode"); 456 assert(pc[2] == 0x24, "not a FIST opcode"); 457 return true; 458 } else if (op == 0xF7) { 459 // IDIV 460 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); 461 } else { 462 // TODO: handle more cases if we are using other x86 instructions 463 // that can generate SIGFPE signal on linux. 464 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op); 465 fatal("please update this code."); 466 } 467 #endif // AMD64 468 } else if (sig == SIGSEGV && 469 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) { 470 // Determination of interpreter/vtable stub/compiled code null exception 471 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); 472 } 473 } else if (thread->thread_state() == _thread_in_vm && 474 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */ 475 thread->doing_unsafe_access()) { 476 stub = StubRoutines::handler_for_unsafe_access(); 477 } 478 479 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in 480 // and the heap gets shrunk before the field access. 481 if ((sig == SIGSEGV) || (sig == SIGBUS)) { 482 address addr = JNI_FastGetField::find_slowcase_pc(pc); 483 if (addr != (address)-1) { 484 stub = addr; 485 } 486 } 487 488 // Check to see if we caught the safepoint code in the 489 // process of write protecting the memory serialization page. 490 // It write enables the page immediately after protecting it 491 // so we can just return to retry the write. 492 if ((sig == SIGSEGV) && 493 os::is_memory_serialize_page(thread, (address) info->si_addr)) { 494 // Block current thread until the memory serialize page permission restored. 495 os::block_on_serialize_page_trap(); 496 return true; 497 } 498 } 499 500 #ifndef AMD64 501 // Execution protection violation 502 // 503 // This should be kept as the last step in the triage. We don't 504 // have a dedicated trap number for a no-execute fault, so be 505 // conservative and allow other handlers the first shot. 506 // 507 // Note: We don't test that info->si_code == SEGV_ACCERR here. 508 // this si_code is so generic that it is almost meaningless; and 509 // the si_code for this condition may change in the future. 510 // Furthermore, a false-positive should be harmless. 511 if (UnguardOnExecutionViolation > 0 && 512 (sig == SIGSEGV || sig == SIGBUS) && 513 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) { 514 int page_size = os::vm_page_size(); 515 address addr = (address) info->si_addr; 516 address pc = os::Linux::ucontext_get_pc(uc); 517 // Make sure the pc and the faulting address are sane. 518 // 519 // If an instruction spans a page boundary, and the page containing 520 // the beginning of the instruction is executable but the following 521 // page is not, the pc and the faulting address might be slightly 522 // different - we still want to unguard the 2nd page in this case. 523 // 524 // 15 bytes seems to be a (very) safe value for max instruction size. 525 bool pc_is_near_addr = 526 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15); 527 bool instr_spans_page_boundary = 528 (align_size_down((intptr_t) pc ^ (intptr_t) addr, 529 (intptr_t) page_size) > 0); 530 531 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) { 532 static volatile address last_addr = 533 (address) os::non_memory_address_word(); 534 535 // In conservative mode, don't unguard unless the address is in the VM 536 if (addr != last_addr && 537 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) { 538 539 // Set memory to RWX and retry 540 address page_start = 541 (address) align_size_down((intptr_t) addr, (intptr_t) page_size); 542 bool res = os::protect_memory((char*) page_start, page_size, 543 os::MEM_PROT_RWX); 544 545 if (PrintMiscellaneous && Verbose) { 546 char buf[256]; 547 jio_snprintf(buf, sizeof(buf), "Execution protection violation " 548 "at " INTPTR_FORMAT 549 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr, 550 page_start, (res ? "success" : "failed"), errno); 551 tty->print_raw_cr(buf); 552 } 553 stub = pc; 554 555 // Set last_addr so if we fault again at the same address, we don't end 556 // up in an endless loop. 557 // 558 // There are two potential complications here. Two threads trapping at 559 // the same address at the same time could cause one of the threads to 560 // think it already unguarded, and abort the VM. Likely very rare. 561 // 562 // The other race involves two threads alternately trapping at 563 // different addresses and failing to unguard the page, resulting in 564 // an endless loop. This condition is probably even more unlikely than 565 // the first. 566 // 567 // Although both cases could be avoided by using locks or thread local 568 // last_addr, these solutions are unnecessary complication: this 569 // handler is a best-effort safety net, not a complete solution. It is 570 // disabled by default and should only be used as a workaround in case 571 // we missed any no-execute-unsafe VM code. 572 573 last_addr = addr; 574 } 575 } 576 } 577 #endif // !AMD64 578 579 if (stub != NULL) { 580 // save all thread context in case we need to restore it 581 if (thread != NULL) thread->set_saved_exception_pc(pc); 582 583 os::Linux::ucontext_set_pc(uc, stub); 584 return true; 585 } 586 587 // signal-chaining 588 if (os::Linux::chained_handler(sig, info, ucVoid)) { 589 return true; 590 } 591 592 if (!abort_if_unrecognized) { 593 // caller wants another chance, so give it to him 594 return false; 595 } 596 597 if (pc == NULL && uc != NULL) { 598 pc = os::Linux::ucontext_get_pc(uc); 599 } 600 601 // unmask current signal 602 sigset_t newset; 603 sigemptyset(&newset); 604 sigaddset(&newset, sig); 605 sigprocmask(SIG_UNBLOCK, &newset, NULL); 606 607 VMError::report_and_die(t, sig, pc, info, ucVoid); 608 609 ShouldNotReachHere(); 610 return true; // Mute compiler 611 } 612 613 void os::Linux::init_thread_fpu_state(void) { 614 #ifndef AMD64 615 // set fpu to 53 bit precision 616 set_fpu_control_word(0x27f); 617 #endif // !AMD64 618 } 619 620 int os::Linux::get_fpu_control_word(void) { 621 #ifdef AMD64 622 return 0; 623 #else 624 int fpu_control; 625 _FPU_GETCW(fpu_control); 626 return fpu_control & 0xffff; 627 #endif // AMD64 628 } 629 630 void os::Linux::set_fpu_control_word(int fpu_control) { 631 #ifndef AMD64 632 _FPU_SETCW(fpu_control); 633 #endif // !AMD64 634 } 635 636 // Check that the linux kernel version is 2.4 or higher since earlier 637 // versions do not support SSE without patches. 638 bool os::supports_sse() { 639 #ifdef AMD64 640 return true; 641 #else 642 struct utsname uts; 643 if( uname(&uts) != 0 ) return false; // uname fails? 644 char *minor_string; 645 int major = strtol(uts.release,&minor_string,10); 646 int minor = strtol(minor_string+1,NULL,10); 647 bool result = (major > 2 || (major==2 && minor >= 4)); 648 #ifndef PRODUCT 649 if (PrintMiscellaneous && Verbose) { 650 tty->print("OS version is %d.%d, which %s support SSE/SSE2\n", 651 major,minor, result ? "DOES" : "does NOT"); 652 } 653 #endif 654 return result; 655 #endif // AMD64 656 } 657 658 bool os::is_allocatable(size_t bytes) { 659 #ifdef AMD64 660 // unused on amd64? 661 return true; 662 #else 663 664 if (bytes < 2 * G) { 665 return true; 666 } 667 668 char* addr = reserve_memory(bytes, NULL); 669 670 if (addr != NULL) { 671 release_memory(addr, bytes); 672 } 673 674 return addr != NULL; 675 #endif // AMD64 676 } 677 678 //////////////////////////////////////////////////////////////////////////////// 679 // thread stack 680 681 #ifdef AMD64 682 size_t os::Linux::min_stack_allowed = 64 * K; 683 #else 684 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K; 685 #endif // AMD64 686 687 // return default stack size for thr_type 688 size_t os::Linux::default_stack_size(os::ThreadType thr_type) { 689 // default stack size (compiler thread needs larger stack) 690 #ifdef AMD64 691 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M); 692 #else 693 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K); 694 #endif // AMD64 695 return s; 696 } 697 698 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 699 // Creating guard page is very expensive. Java thread has HotSpot 700 // guard page, only enable glibc guard page for non-Java threads. 701 return (thr_type == java_thread ? 0 : page_size()); 702 } 703 704 // Java thread: 705 // 706 // Low memory addresses 707 // +------------------------+ 708 // | |\ JavaThread created by VM does not have glibc 709 // | glibc guard page | - guard, attached Java thread usually has 710 // | |/ 1 page glibc guard. 711 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 712 // | |\ 713 // | HotSpot Guard Pages | - red and yellow pages 714 // | |/ 715 // +------------------------+ JavaThread::stack_yellow_zone_base() 716 // | |\ 717 // | Normal Stack | - 718 // | |/ 719 // P2 +------------------------+ Thread::stack_base() 720 // 721 // Non-Java thread: 722 // 723 // Low memory addresses 724 // +------------------------+ 725 // | |\ 726 // | glibc guard page | - usually 1 page 727 // | |/ 728 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 729 // | |\ 730 // | Normal Stack | - 731 // | |/ 732 // P2 +------------------------+ Thread::stack_base() 733 // 734 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from 735 // pthread_attr_getstack() 736 737 static void current_stack_region(address * bottom, size_t * size) { 738 if (os::Linux::is_initial_thread()) { 739 // initial thread needs special handling because pthread_getattr_np() 740 // may return bogus value. 741 *bottom = os::Linux::initial_thread_stack_bottom(); 742 *size = os::Linux::initial_thread_stack_size(); 743 } else { 744 pthread_attr_t attr; 745 746 int rslt = pthread_getattr_np(pthread_self(), &attr); 747 748 // JVM needs to know exact stack location, abort if it fails 749 if (rslt != 0) { 750 if (rslt == ENOMEM) { 751 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 752 } else { 753 fatal("pthread_getattr_np failed with errno = %d", rslt); 754 } 755 } 756 757 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 758 fatal("Can not locate current stack attributes!"); 759 } 760 761 pthread_attr_destroy(&attr); 762 763 } 764 assert(os::current_stack_pointer() >= *bottom && 765 os::current_stack_pointer() < *bottom + *size, "just checking"); 766 } 767 768 address os::current_stack_base() { 769 address bottom; 770 size_t size; 771 current_stack_region(&bottom, &size); 772 return (bottom + size); 773 } 774 775 size_t os::current_stack_size() { 776 // stack size includes normal stack and HotSpot guard pages 777 address bottom; 778 size_t size; 779 current_stack_region(&bottom, &size); 780 return size; 781 } 782 783 ///////////////////////////////////////////////////////////////////////////// 784 // helper functions for fatal error handler 785 786 void os::print_context(outputStream *st, void *context) { 787 if (context == NULL) return; 788 789 ucontext_t *uc = (ucontext_t*)context; 790 st->print_cr("Registers:"); 791 #ifdef AMD64 792 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]); 793 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]); 794 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]); 795 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]); 796 st->cr(); 797 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]); 798 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]); 799 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]); 800 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]); 801 st->cr(); 802 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]); 803 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]); 804 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]); 805 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]); 806 st->cr(); 807 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]); 808 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]); 809 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]); 810 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]); 811 st->cr(); 812 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]); 813 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]); 814 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]); 815 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]); 816 st->cr(); 817 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]); 818 #else 819 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]); 820 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]); 821 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]); 822 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]); 823 st->cr(); 824 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]); 825 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]); 826 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]); 827 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]); 828 st->cr(); 829 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]); 830 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]); 831 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2); 832 #endif // AMD64 833 st->cr(); 834 st->cr(); 835 836 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc); 837 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp)); 838 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t)); 839 st->cr(); 840 841 // Note: it may be unsafe to inspect memory near pc. For example, pc may 842 // point to garbage if entry point in an nmethod is corrupted. Leave 843 // this at the end, and hope for the best. 844 address pc = os::Linux::ucontext_get_pc(uc); 845 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc)); 846 print_hex_dump(st, pc - 32, pc + 32, sizeof(char)); 847 } 848 849 void os::print_register_info(outputStream *st, void *context) { 850 if (context == NULL) return; 851 852 ucontext_t *uc = (ucontext_t*)context; 853 854 st->print_cr("Register to memory mapping:"); 855 st->cr(); 856 857 // this is horrendously verbose but the layout of the registers in the 858 // context does not match how we defined our abstract Register set, so 859 // we can't just iterate through the gregs area 860 861 // this is only for the "general purpose" registers 862 863 #ifdef AMD64 864 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]); 865 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]); 866 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]); 867 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]); 868 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]); 869 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]); 870 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]); 871 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]); 872 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]); 873 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]); 874 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]); 875 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]); 876 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]); 877 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]); 878 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]); 879 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]); 880 #else 881 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]); 882 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]); 883 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]); 884 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]); 885 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]); 886 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]); 887 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]); 888 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]); 889 #endif // AMD64 890 891 st->cr(); 892 } 893 894 void os::setup_fpu() { 895 #ifndef AMD64 896 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std(); 897 __asm__ volatile ( "fldcw (%0)" : 898 : "r" (fpu_cntrl) : "memory"); 899 #endif // !AMD64 900 } 901 902 #ifndef PRODUCT 903 void os::verify_stack_alignment() { 904 #ifdef AMD64 905 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment"); 906 #endif 907 } 908 #endif 909 910 911 /* 912 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit 913 * updates (JDK-8023956). 914 */ 915 void os::workaround_expand_exec_shield_cs_limit() { 916 #if defined(IA32) 917 size_t page_size = os::vm_page_size(); 918 /* 919 * Take the highest VA the OS will give us and exec 920 * 921 * Although using -(pagesz) as mmap hint works on newer kernel as you would 922 * think, older variants affected by this work-around don't (search forward only). 923 * 924 * On the affected distributions, we understand the memory layout to be: 925 * 926 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT. 927 * 928 * A few pages south main stack will do it. 929 * 930 * If we are embedded in an app other than launcher (initial != main stack), 931 * we don't have much control or understanding of the address space, just let it slide. 932 */ 933 char* hint = (char*) (Linux::initial_thread_stack_bottom() - 934 ((StackReservedPages + StackYellowPages + StackRedPages + 1) * page_size)); 935 char* codebuf = os::attempt_reserve_memory_at(page_size, hint); 936 if ( (codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true)) ) { 937 return; // No matter, we tried, best effort. 938 } 939 940 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal); 941 942 if (PrintMiscellaneous && (Verbose || WizardMode)) { 943 tty->print_cr("[CS limit NX emulation work-around, exec code at: %p]", codebuf); 944 } 945 946 // Some code to exec: the 'ret' instruction 947 codebuf[0] = 0xC3; 948 949 // Call the code in the codebuf 950 __asm__ volatile("call *%0" : : "r"(codebuf)); 951 952 // keep the page mapped so CS limit isn't reduced. 953 #endif 954 } 955 956 int os::extra_bang_size_in_bytes() { 957 // JDK-8050147 requires the full cache line bang for x86. 958 return VM_Version::L1_line_size(); 959 }