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