1 /* 2 * Copyright (c) 1999, 2016, 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/codeCache.hpp" 31 #include "code/icBuffer.hpp" 32 #include "code/vtableStubs.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "jvm_linux.h" 35 #include "memory/allocation.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(const 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(const ucontext_t * uc) { 128 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP]; 129 } 130 131 intptr_t* os::Linux::ucontext_get_fp(const 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 const 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(const void* ucVoid, 152 intptr_t** ret_sp, intptr_t** ret_fp) { 153 154 ExtendedPC epc; 155 const ucontext_t* uc = (const 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(const 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 // ebp is for this frame (_get_previous_fp). We want the ebp for the 239 // caller of os::current_frame*(), so go up two frames. However, for 240 // optimized builds, _get_previous_fp() will be inlined, so only go 241 // up 1 frame in that case. 242 #ifdef _NMT_NOINLINE_ 243 return **(intptr_t***)ebp; 244 #else 245 return *ebp; 246 #endif 247 } 248 249 250 frame os::current_frame() { 251 intptr_t* fp = _get_previous_fp(); 252 frame myframe((intptr_t*)os::current_stack_pointer(), 253 (intptr_t*)fp, 254 CAST_FROM_FN_PTR(address, os::current_frame)); 255 if (os::is_first_C_frame(&myframe)) { 256 // stack is not walkable 257 return frame(); 258 } else { 259 return os::get_sender_for_C_frame(&myframe); 260 } 261 } 262 263 // Utility functions 264 265 // From IA32 System Programming Guide 266 enum { 267 trap_page_fault = 0xE 268 }; 269 270 extern "C" JNIEXPORT int 271 JVM_handle_linux_signal(int sig, 272 siginfo_t* info, 273 void* ucVoid, 274 int abort_if_unrecognized) { 275 ucontext_t* uc = (ucontext_t*) ucVoid; 276 277 Thread* t = Thread::current_or_null_safe(); 278 279 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away 280 // (no destructors can be run) 281 os::WatcherThreadCrashProtection::check_crash_protection(sig, t); 282 283 SignalHandlerMark shm(t); 284 285 // Note: it's not uncommon that JNI code uses signal/sigset to install 286 // then restore certain signal handler (e.g. to temporarily block SIGPIPE, 287 // or have a SIGILL handler when detecting CPU type). When that happens, 288 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To 289 // avoid unnecessary crash when libjsig is not preloaded, try handle signals 290 // that do not require siginfo/ucontext first. 291 292 if (sig == SIGPIPE || sig == SIGXFSZ) { 293 // allow chained handler to go first 294 if (os::Linux::chained_handler(sig, info, ucVoid)) { 295 return true; 296 } else { 297 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219 298 return true; 299 } 300 } 301 302 JavaThread* thread = NULL; 303 VMThread* vmthread = NULL; 304 if (os::Linux::signal_handlers_are_installed) { 305 if (t != NULL ){ 306 if(t->is_Java_thread()) { 307 thread = (JavaThread*)t; 308 } 309 else if(t->is_VM_thread()){ 310 vmthread = (VMThread *)t; 311 } 312 } 313 } 314 /* 315 NOTE: does not seem to work on linux. 316 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) { 317 // can't decode this kind of signal 318 info = NULL; 319 } else { 320 assert(sig == info->si_signo, "bad siginfo"); 321 } 322 */ 323 // decide if this trap can be handled by a stub 324 address stub = NULL; 325 326 address pc = NULL; 327 328 //%note os_trap_1 329 if (info != NULL && uc != NULL && thread != NULL) { 330 pc = (address) os::Linux::ucontext_get_pc(uc); 331 332 if (StubRoutines::is_safefetch_fault(pc)) { 333 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc)); 334 return 1; 335 } 336 337 #ifndef AMD64 338 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs 339 // This can happen in any running code (currently more frequently in 340 // interpreter code but has been seen in compiled code) 341 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) { 342 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due " 343 "to unstable signal handling in this distribution."); 344 } 345 #endif // AMD64 346 347 // Handle ALL stack overflow variations here 348 if (sig == SIGSEGV) { 349 address addr = (address) info->si_addr; 350 351 // check if fault address is within thread stack 352 if (thread->on_local_stack(addr)) { 353 // stack overflow 354 if (thread->in_stack_yellow_reserved_zone(addr)) { 355 if (thread->thread_state() == _thread_in_Java) { 356 if (thread->in_stack_reserved_zone(addr)) { 357 frame fr; 358 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) { 359 assert(fr.is_java_frame(), "Must be a Java frame"); 360 frame activation = 361 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr); 362 if (activation.sp() != NULL) { 363 thread->disable_stack_reserved_zone(); 364 if (activation.is_interpreted_frame()) { 365 thread->set_reserved_stack_activation((address)( 366 activation.fp() + frame::interpreter_frame_initial_sp_offset)); 367 } else { 368 thread->set_reserved_stack_activation((address)activation.unextended_sp()); 369 } 370 return 1; 371 } 372 } 373 } 374 // Throw a stack overflow exception. Guard pages will be reenabled 375 // while unwinding the stack. 376 thread->disable_stack_yellow_reserved_zone(); 377 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW); 378 } else { 379 // Thread was in the vm or native code. Return and try to finish. 380 thread->disable_stack_yellow_reserved_zone(); 381 return 1; 382 } 383 } else if (thread->in_stack_red_zone(addr)) { 384 // Fatal red zone violation. Disable the guard pages and fall through 385 // to handle_unexpected_exception way down below. 386 thread->disable_stack_red_zone(); 387 tty->print_raw_cr("An irrecoverable stack overflow has occurred."); 388 389 // This is a likely cause, but hard to verify. Let's just print 390 // it as a hint. 391 tty->print_raw_cr("Please check if any of your loaded .so files has " 392 "enabled executable stack (see man page execstack(8))"); 393 } else { 394 // Accessing stack address below sp may cause SEGV if current 395 // thread has MAP_GROWSDOWN stack. This should only happen when 396 // current thread was created by user code with MAP_GROWSDOWN flag 397 // and then attached to VM. See notes in os_linux.cpp. 398 if (thread->osthread()->expanding_stack() == 0) { 399 thread->osthread()->set_expanding_stack(); 400 if (os::Linux::manually_expand_stack(thread, addr)) { 401 thread->osthread()->clear_expanding_stack(); 402 return 1; 403 } 404 thread->osthread()->clear_expanding_stack(); 405 } else { 406 fatal("recursive segv. expanding stack."); 407 } 408 } 409 } 410 } 411 412 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) { 413 // Verify that OS save/restore AVX registers. 414 stub = VM_Version::cpuinfo_cont_addr(); 415 } 416 417 if (thread->thread_state() == _thread_in_Java) { 418 // Java thread running in Java code => find exception handler if any 419 // a fault inside compiled code, the interpreter, or a stub 420 421 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) { 422 stub = SharedRuntime::get_poll_stub(pc); 423 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) { 424 // BugId 4454115: A read from a MappedByteBuffer can fault 425 // here if the underlying file has been truncated. 426 // Do not crash the VM in such a case. 427 CodeBlob* cb = CodeCache::find_blob_unsafe(pc); 428 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL; 429 if (nm != NULL && nm->has_unsafe_access()) { 430 address next_pc = Assembler::locate_next_instruction(pc); 431 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 432 } 433 } 434 else 435 436 #ifdef AMD64 437 if (sig == SIGFPE && 438 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) { 439 stub = 440 SharedRuntime:: 441 continuation_for_implicit_exception(thread, 442 pc, 443 SharedRuntime:: 444 IMPLICIT_DIVIDE_BY_ZERO); 445 #else 446 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) { 447 // HACK: si_code does not work on linux 2.2.12-20!!! 448 int op = pc[0]; 449 if (op == 0xDB) { 450 // FIST 451 // TODO: The encoding of D2I in i486.ad can cause an exception 452 // prior to the fist instruction if there was an invalid operation 453 // pending. We want to dismiss that exception. From the win_32 454 // side it also seems that if it really was the fist causing 455 // the exception that we do the d2i by hand with different 456 // rounding. Seems kind of weird. 457 // NOTE: that we take the exception at the NEXT floating point instruction. 458 assert(pc[0] == 0xDB, "not a FIST opcode"); 459 assert(pc[1] == 0x14, "not a FIST opcode"); 460 assert(pc[2] == 0x24, "not a FIST opcode"); 461 return true; 462 } else if (op == 0xF7) { 463 // IDIV 464 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); 465 } else { 466 // TODO: handle more cases if we are using other x86 instructions 467 // that can generate SIGFPE signal on linux. 468 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op); 469 fatal("please update this code."); 470 } 471 #endif // AMD64 472 } else if (sig == SIGSEGV && 473 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) { 474 // Determination of interpreter/vtable stub/compiled code null exception 475 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); 476 } 477 } else if (thread->thread_state() == _thread_in_vm && 478 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */ 479 thread->doing_unsafe_access()) { 480 address next_pc = Assembler::locate_next_instruction(pc); 481 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 482 } 483 484 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in 485 // and the heap gets shrunk before the field access. 486 if ((sig == SIGSEGV) || (sig == SIGBUS)) { 487 address addr = JNI_FastGetField::find_slowcase_pc(pc); 488 if (addr != (address)-1) { 489 stub = addr; 490 } 491 } 492 493 // Check to see if we caught the safepoint code in the 494 // process of write protecting the memory serialization page. 495 // It write enables the page immediately after protecting it 496 // so we can just return to retry the write. 497 if ((sig == SIGSEGV) && 498 os::is_memory_serialize_page(thread, (address) info->si_addr)) { 499 // Block current thread until the memory serialize page permission restored. 500 os::block_on_serialize_page_trap(); 501 return true; 502 } 503 } 504 505 #ifndef AMD64 506 // Execution protection violation 507 // 508 // This should be kept as the last step in the triage. We don't 509 // have a dedicated trap number for a no-execute fault, so be 510 // conservative and allow other handlers the first shot. 511 // 512 // Note: We don't test that info->si_code == SEGV_ACCERR here. 513 // this si_code is so generic that it is almost meaningless; and 514 // the si_code for this condition may change in the future. 515 // Furthermore, a false-positive should be harmless. 516 if (UnguardOnExecutionViolation > 0 && 517 (sig == SIGSEGV || sig == SIGBUS) && 518 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) { 519 int page_size = os::vm_page_size(); 520 address addr = (address) info->si_addr; 521 address pc = os::Linux::ucontext_get_pc(uc); 522 // Make sure the pc and the faulting address are sane. 523 // 524 // If an instruction spans a page boundary, and the page containing 525 // the beginning of the instruction is executable but the following 526 // page is not, the pc and the faulting address might be slightly 527 // different - we still want to unguard the 2nd page in this case. 528 // 529 // 15 bytes seems to be a (very) safe value for max instruction size. 530 bool pc_is_near_addr = 531 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15); 532 bool instr_spans_page_boundary = 533 (align_size_down((intptr_t) pc ^ (intptr_t) addr, 534 (intptr_t) page_size) > 0); 535 536 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) { 537 static volatile address last_addr = 538 (address) os::non_memory_address_word(); 539 540 // In conservative mode, don't unguard unless the address is in the VM 541 if (addr != last_addr && 542 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) { 543 544 // Set memory to RWX and retry 545 address page_start = 546 (address) align_size_down((intptr_t) addr, (intptr_t) page_size); 547 bool res = os::protect_memory((char*) page_start, page_size, 548 os::MEM_PROT_RWX); 549 550 log_debug(os)("Execution protection violation " 551 "at " INTPTR_FORMAT 552 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr), 553 p2i(page_start), (res ? "success" : "failed"), errno); 554 stub = pc; 555 556 // Set last_addr so if we fault again at the same address, we don't end 557 // up in an endless loop. 558 // 559 // There are two potential complications here. Two threads trapping at 560 // the same address at the same time could cause one of the threads to 561 // think it already unguarded, and abort the VM. Likely very rare. 562 // 563 // The other race involves two threads alternately trapping at 564 // different addresses and failing to unguard the page, resulting in 565 // an endless loop. This condition is probably even more unlikely than 566 // the first. 567 // 568 // Although both cases could be avoided by using locks or thread local 569 // last_addr, these solutions are unnecessary complication: this 570 // handler is a best-effort safety net, not a complete solution. It is 571 // disabled by default and should only be used as a workaround in case 572 // we missed any no-execute-unsafe VM code. 573 574 last_addr = addr; 575 } 576 } 577 } 578 #endif // !AMD64 579 580 if (stub != NULL) { 581 // save all thread context in case we need to restore it 582 if (thread != NULL) thread->set_saved_exception_pc(pc); 583 584 os::Linux::ucontext_set_pc(uc, stub); 585 return true; 586 } 587 588 // signal-chaining 589 if (os::Linux::chained_handler(sig, info, ucVoid)) { 590 return true; 591 } 592 593 if (!abort_if_unrecognized) { 594 // caller wants another chance, so give it to him 595 return false; 596 } 597 598 if (pc == NULL && uc != NULL) { 599 pc = os::Linux::ucontext_get_pc(uc); 600 } 601 602 // unmask current signal 603 sigset_t newset; 604 sigemptyset(&newset); 605 sigaddset(&newset, sig); 606 sigprocmask(SIG_UNBLOCK, &newset, NULL); 607 608 VMError::report_and_die(t, sig, pc, info, ucVoid); 609 610 ShouldNotReachHere(); 611 return true; // Mute compiler 612 } 613 614 void os::Linux::init_thread_fpu_state(void) { 615 #ifndef AMD64 616 // set fpu to 53 bit precision 617 set_fpu_control_word(0x27f); 618 #endif // !AMD64 619 } 620 621 int os::Linux::get_fpu_control_word(void) { 622 #ifdef AMD64 623 return 0; 624 #else 625 int fpu_control; 626 _FPU_GETCW(fpu_control); 627 return fpu_control & 0xffff; 628 #endif // AMD64 629 } 630 631 void os::Linux::set_fpu_control_word(int fpu_control) { 632 #ifndef AMD64 633 _FPU_SETCW(fpu_control); 634 #endif // !AMD64 635 } 636 637 // Check that the linux kernel version is 2.4 or higher since earlier 638 // versions do not support SSE without patches. 639 bool os::supports_sse() { 640 #ifdef AMD64 641 return true; 642 #else 643 struct utsname uts; 644 if( uname(&uts) != 0 ) return false; // uname fails? 645 char *minor_string; 646 int major = strtol(uts.release,&minor_string,10); 647 int minor = strtol(minor_string+1,NULL,10); 648 bool result = (major > 2 || (major==2 && minor >= 4)); 649 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2", 650 major,minor, result ? "DOES" : "does NOT"); 651 return result; 652 #endif // AMD64 653 } 654 655 bool os::is_allocatable(size_t bytes) { 656 #ifdef AMD64 657 // unused on amd64? 658 return true; 659 #else 660 661 if (bytes < 2 * G) { 662 return true; 663 } 664 665 char* addr = reserve_memory(bytes, NULL); 666 667 if (addr != NULL) { 668 release_memory(addr, bytes); 669 } 670 671 return addr != NULL; 672 #endif // AMD64 673 } 674 675 //////////////////////////////////////////////////////////////////////////////// 676 // thread stack 677 678 #ifdef AMD64 679 size_t os::Linux::min_stack_allowed = 64 * K; 680 #else 681 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K; 682 #endif // AMD64 683 684 // return default stack size for thr_type 685 size_t os::Linux::default_stack_size(os::ThreadType thr_type) { 686 // default stack size (compiler thread needs larger stack) 687 #ifdef AMD64 688 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M); 689 #else 690 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K); 691 #endif // AMD64 692 return s; 693 } 694 695 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 696 // Creating guard page is very expensive. Java thread has HotSpot 697 // guard page, only enable glibc guard page for non-Java threads. 698 return (thr_type == java_thread ? 0 : page_size()); 699 } 700 701 // Java thread: 702 // 703 // Low memory addresses 704 // +------------------------+ 705 // | |\ JavaThread created by VM does not have glibc 706 // | glibc guard page | - guard, attached Java thread usually has 707 // | |/ 1 page glibc guard. 708 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 709 // | |\ 710 // | HotSpot Guard Pages | - red and yellow pages 711 // | |/ 712 // +------------------------+ JavaThread::stack_yellow_zone_base() 713 // | |\ 714 // | Normal Stack | - 715 // | |/ 716 // P2 +------------------------+ Thread::stack_base() 717 // 718 // Non-Java thread: 719 // 720 // Low memory addresses 721 // +------------------------+ 722 // | |\ 723 // | glibc guard page | - usually 1 page 724 // | |/ 725 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 726 // | |\ 727 // | Normal Stack | - 728 // | |/ 729 // P2 +------------------------+ Thread::stack_base() 730 // 731 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from 732 // pthread_attr_getstack() 733 734 static void current_stack_region(address * bottom, size_t * size) { 735 if (os::Linux::is_initial_thread()) { 736 // initial thread needs special handling because pthread_getattr_np() 737 // may return bogus value. 738 *bottom = os::Linux::initial_thread_stack_bottom(); 739 *size = os::Linux::initial_thread_stack_size(); 740 } else { 741 pthread_attr_t attr; 742 743 int rslt = pthread_getattr_np(pthread_self(), &attr); 744 745 // JVM needs to know exact stack location, abort if it fails 746 if (rslt != 0) { 747 if (rslt == ENOMEM) { 748 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 749 } else { 750 fatal("pthread_getattr_np failed with errno = %d", rslt); 751 } 752 } 753 754 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 755 fatal("Can not locate current stack attributes!"); 756 } 757 758 pthread_attr_destroy(&attr); 759 760 } 761 assert(os::current_stack_pointer() >= *bottom && 762 os::current_stack_pointer() < *bottom + *size, "just checking"); 763 } 764 765 address os::current_stack_base() { 766 address bottom; 767 size_t size; 768 current_stack_region(&bottom, &size); 769 return (bottom + size); 770 } 771 772 size_t os::current_stack_size() { 773 // stack size includes normal stack and HotSpot guard pages 774 address bottom; 775 size_t size; 776 current_stack_region(&bottom, &size); 777 return size; 778 } 779 780 ///////////////////////////////////////////////////////////////////////////// 781 // helper functions for fatal error handler 782 783 void os::print_context(outputStream *st, const void *context) { 784 if (context == NULL) return; 785 786 const ucontext_t *uc = (const ucontext_t*)context; 787 st->print_cr("Registers:"); 788 #ifdef AMD64 789 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]); 790 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]); 791 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]); 792 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]); 793 st->cr(); 794 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]); 795 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]); 796 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]); 797 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]); 798 st->cr(); 799 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]); 800 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]); 801 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]); 802 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]); 803 st->cr(); 804 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]); 805 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]); 806 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]); 807 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]); 808 st->cr(); 809 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]); 810 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]); 811 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]); 812 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]); 813 st->cr(); 814 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]); 815 #else 816 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]); 817 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]); 818 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]); 819 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]); 820 st->cr(); 821 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]); 822 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]); 823 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]); 824 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]); 825 st->cr(); 826 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]); 827 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]); 828 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2); 829 #endif // AMD64 830 st->cr(); 831 st->cr(); 832 833 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc); 834 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp)); 835 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t)); 836 st->cr(); 837 838 // Note: it may be unsafe to inspect memory near pc. For example, pc may 839 // point to garbage if entry point in an nmethod is corrupted. Leave 840 // this at the end, and hope for the best. 841 address pc = os::Linux::ucontext_get_pc(uc); 842 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc)); 843 print_hex_dump(st, pc - 32, pc + 32, sizeof(char)); 844 } 845 846 void os::print_register_info(outputStream *st, const void *context) { 847 if (context == NULL) return; 848 849 const ucontext_t *uc = (const ucontext_t*)context; 850 851 st->print_cr("Register to memory mapping:"); 852 st->cr(); 853 854 // this is horrendously verbose but the layout of the registers in the 855 // context does not match how we defined our abstract Register set, so 856 // we can't just iterate through the gregs area 857 858 // this is only for the "general purpose" registers 859 860 #ifdef AMD64 861 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]); 862 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]); 863 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]); 864 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]); 865 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]); 866 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]); 867 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]); 868 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]); 869 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]); 870 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]); 871 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]); 872 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]); 873 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]); 874 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]); 875 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]); 876 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]); 877 #else 878 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]); 879 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]); 880 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]); 881 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]); 882 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]); 883 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]); 884 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]); 885 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]); 886 #endif // AMD64 887 888 st->cr(); 889 } 890 891 void os::setup_fpu() { 892 #ifndef AMD64 893 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std(); 894 __asm__ volatile ( "fldcw (%0)" : 895 : "r" (fpu_cntrl) : "memory"); 896 #endif // !AMD64 897 } 898 899 #ifndef PRODUCT 900 void os::verify_stack_alignment() { 901 #ifdef AMD64 902 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment"); 903 #endif 904 } 905 #endif 906 907 908 /* 909 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit 910 * updates (JDK-8023956). 911 */ 912 void os::workaround_expand_exec_shield_cs_limit() { 913 #if defined(IA32) 914 size_t page_size = os::vm_page_size(); 915 /* 916 * Take the highest VA the OS will give us and exec 917 * 918 * Although using -(pagesz) as mmap hint works on newer kernel as you would 919 * think, older variants affected by this work-around don't (search forward only). 920 * 921 * On the affected distributions, we understand the memory layout to be: 922 * 923 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT. 924 * 925 * A few pages south main stack will do it. 926 * 927 * If we are embedded in an app other than launcher (initial != main stack), 928 * we don't have much control or understanding of the address space, just let it slide. 929 */ 930 char* hint = (char*)(Linux::initial_thread_stack_bottom() - 931 (JavaThread::stack_guard_zone_size() + page_size)); 932 char* codebuf = os::attempt_reserve_memory_at(page_size, hint); 933 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) { 934 return; // No matter, we tried, best effort. 935 } 936 937 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal); 938 939 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf); 940 941 // Some code to exec: the 'ret' instruction 942 codebuf[0] = 0xC3; 943 944 // Call the code in the codebuf 945 __asm__ volatile("call *%0" : : "r"(codebuf)); 946 947 // keep the page mapped so CS limit isn't reduced. 948 #endif 949 } 950 951 int os::extra_bang_size_in_bytes() { 952 // JDK-8050147 requires the full cache line bang for x86. 953 return VM_Version::L1_line_size(); 954 }