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 // get_frame_at_stack_banging_point() is only called when we 195 // have well defined stacks so java_sender() calls do not need 196 // to assert safe_for_sender() first. 197 *fr = fr->java_sender(); 198 } 199 } else { 200 // more complex code with compiled code 201 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above"); 202 CodeBlob* cb = CodeCache::find_blob(pc); 203 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) { 204 // Not sure where the pc points to, fallback to default 205 // stack overflow handling 206 return false; 207 } else { 208 // in compiled code, the stack banging is performed just after the return pc 209 // has been pushed on the stack 210 intptr_t* fp = os::Linux::ucontext_get_fp(uc); 211 intptr_t* sp = os::Linux::ucontext_get_sp(uc); 212 *fr = frame(sp + 1, fp, (address)*sp); 213 if (!fr->is_java_frame()) { 214 assert(!fr->is_first_frame(), "Safety check"); 215 // See java_sender() comment above. 216 *fr = fr->java_sender(); 217 } 218 } 219 } 220 assert(fr->is_java_frame(), "Safety check"); 221 return true; 222 } 223 224 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get 225 // turned off by -fomit-frame-pointer, 226 frame os::get_sender_for_C_frame(frame* fr) { 227 return frame(fr->sender_sp(), fr->link(), fr->sender_pc()); 228 } 229 230 intptr_t* _get_previous_fp() { 231 #ifdef SPARC_WORKS 232 register intptr_t **ebp; 233 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp)); 234 #elif defined(__clang__) 235 intptr_t **ebp; 236 __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):); 237 #else 238 register intptr_t **ebp __asm__ (SPELL_REG_FP); 239 #endif 240 // ebp is for this frame (_get_previous_fp). We want the ebp for the 241 // caller of os::current_frame*(), so go up two frames. However, for 242 // optimized builds, _get_previous_fp() will be inlined, so only go 243 // up 1 frame in that case. 244 #ifdef _NMT_NOINLINE_ 245 return **(intptr_t***)ebp; 246 #else 247 return *ebp; 248 #endif 249 } 250 251 252 frame os::current_frame() { 253 intptr_t* fp = _get_previous_fp(); 254 frame myframe((intptr_t*)os::current_stack_pointer(), 255 (intptr_t*)fp, 256 CAST_FROM_FN_PTR(address, os::current_frame)); 257 if (os::is_first_C_frame(&myframe)) { 258 // stack is not walkable 259 return frame(); 260 } else { 261 return os::get_sender_for_C_frame(&myframe); 262 } 263 } 264 265 // Utility functions 266 267 // From IA32 System Programming Guide 268 enum { 269 trap_page_fault = 0xE 270 }; 271 272 extern "C" JNIEXPORT int 273 JVM_handle_linux_signal(int sig, 274 siginfo_t* info, 275 void* ucVoid, 276 int abort_if_unrecognized) { 277 ucontext_t* uc = (ucontext_t*) ucVoid; 278 279 Thread* t = Thread::current_or_null_safe(); 280 281 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away 282 // (no destructors can be run) 283 os::WatcherThreadCrashProtection::check_crash_protection(sig, t); 284 285 SignalHandlerMark shm(t); 286 287 // Note: it's not uncommon that JNI code uses signal/sigset to install 288 // then restore certain signal handler (e.g. to temporarily block SIGPIPE, 289 // or have a SIGILL handler when detecting CPU type). When that happens, 290 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To 291 // avoid unnecessary crash when libjsig is not preloaded, try handle signals 292 // that do not require siginfo/ucontext first. 293 294 if (sig == SIGPIPE || sig == SIGXFSZ) { 295 // allow chained handler to go first 296 if (os::Linux::chained_handler(sig, info, ucVoid)) { 297 return true; 298 } else { 299 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219 300 return true; 301 } 302 } 303 304 JavaThread* thread = NULL; 305 VMThread* vmthread = NULL; 306 if (os::Linux::signal_handlers_are_installed) { 307 if (t != NULL ){ 308 if(t->is_Java_thread()) { 309 thread = (JavaThread*)t; 310 } 311 else if(t->is_VM_thread()){ 312 vmthread = (VMThread *)t; 313 } 314 } 315 } 316 /* 317 NOTE: does not seem to work on linux. 318 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) { 319 // can't decode this kind of signal 320 info = NULL; 321 } else { 322 assert(sig == info->si_signo, "bad siginfo"); 323 } 324 */ 325 // decide if this trap can be handled by a stub 326 address stub = NULL; 327 328 address pc = NULL; 329 330 //%note os_trap_1 331 if (info != NULL && uc != NULL && thread != NULL) { 332 pc = (address) os::Linux::ucontext_get_pc(uc); 333 334 if (StubRoutines::is_safefetch_fault(pc)) { 335 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc)); 336 return 1; 337 } 338 339 #ifndef AMD64 340 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs 341 // This can happen in any running code (currently more frequently in 342 // interpreter code but has been seen in compiled code) 343 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) { 344 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due " 345 "to unstable signal handling in this distribution."); 346 } 347 #endif // AMD64 348 349 // Handle ALL stack overflow variations here 350 if (sig == SIGSEGV) { 351 address addr = (address) info->si_addr; 352 353 // check if fault address is within thread stack 354 if (thread->on_local_stack(addr)) { 355 // stack overflow 356 if (thread->in_stack_yellow_reserved_zone(addr)) { 357 if (thread->thread_state() == _thread_in_Java) { 358 if (thread->in_stack_reserved_zone(addr)) { 359 frame fr; 360 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) { 361 assert(fr.is_java_frame(), "Must be a Java frame"); 362 frame activation = 363 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr); 364 if (activation.sp() != NULL) { 365 thread->disable_stack_reserved_zone(); 366 if (activation.is_interpreted_frame()) { 367 thread->set_reserved_stack_activation((address)( 368 activation.fp() + frame::interpreter_frame_initial_sp_offset)); 369 } else { 370 thread->set_reserved_stack_activation((address)activation.unextended_sp()); 371 } 372 return 1; 373 } 374 } 375 } 376 // Throw a stack overflow exception. Guard pages will be reenabled 377 // while unwinding the stack. 378 thread->disable_stack_yellow_reserved_zone(); 379 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW); 380 } else { 381 // Thread was in the vm or native code. Return and try to finish. 382 thread->disable_stack_yellow_reserved_zone(); 383 return 1; 384 } 385 } else if (thread->in_stack_red_zone(addr)) { 386 // Fatal red zone violation. Disable the guard pages and fall through 387 // to handle_unexpected_exception way down below. 388 thread->disable_stack_red_zone(); 389 tty->print_raw_cr("An irrecoverable stack overflow has occurred."); 390 391 // This is a likely cause, but hard to verify. Let's just print 392 // it as a hint. 393 tty->print_raw_cr("Please check if any of your loaded .so files has " 394 "enabled executable stack (see man page execstack(8))"); 395 } else { 396 // Accessing stack address below sp may cause SEGV if current 397 // thread has MAP_GROWSDOWN stack. This should only happen when 398 // current thread was created by user code with MAP_GROWSDOWN flag 399 // and then attached to VM. See notes in os_linux.cpp. 400 if (thread->osthread()->expanding_stack() == 0) { 401 thread->osthread()->set_expanding_stack(); 402 if (os::Linux::manually_expand_stack(thread, addr)) { 403 thread->osthread()->clear_expanding_stack(); 404 return 1; 405 } 406 thread->osthread()->clear_expanding_stack(); 407 } else { 408 fatal("recursive segv. expanding stack."); 409 } 410 } 411 } 412 } 413 414 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) { 415 // Verify that OS save/restore AVX registers. 416 stub = VM_Version::cpuinfo_cont_addr(); 417 } 418 419 if (thread->thread_state() == _thread_in_Java) { 420 // Java thread running in Java code => find exception handler if any 421 // a fault inside compiled code, the interpreter, or a stub 422 423 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) { 424 stub = SharedRuntime::get_poll_stub(pc); 425 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) { 426 // BugId 4454115: A read from a MappedByteBuffer can fault 427 // here if the underlying file has been truncated. 428 // Do not crash the VM in such a case. 429 CodeBlob* cb = CodeCache::find_blob_unsafe(pc); 430 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL; 431 if (nm != NULL && nm->has_unsafe_access()) { 432 address next_pc = Assembler::locate_next_instruction(pc); 433 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 434 } 435 } 436 else 437 438 #ifdef AMD64 439 if (sig == SIGFPE && 440 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) { 441 stub = 442 SharedRuntime:: 443 continuation_for_implicit_exception(thread, 444 pc, 445 SharedRuntime:: 446 IMPLICIT_DIVIDE_BY_ZERO); 447 #else 448 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) { 449 // HACK: si_code does not work on linux 2.2.12-20!!! 450 int op = pc[0]; 451 if (op == 0xDB) { 452 // FIST 453 // TODO: The encoding of D2I in i486.ad can cause an exception 454 // prior to the fist instruction if there was an invalid operation 455 // pending. We want to dismiss that exception. From the win_32 456 // side it also seems that if it really was the fist causing 457 // the exception that we do the d2i by hand with different 458 // rounding. Seems kind of weird. 459 // NOTE: that we take the exception at the NEXT floating point instruction. 460 assert(pc[0] == 0xDB, "not a FIST opcode"); 461 assert(pc[1] == 0x14, "not a FIST opcode"); 462 assert(pc[2] == 0x24, "not a FIST opcode"); 463 return true; 464 } else if (op == 0xF7) { 465 // IDIV 466 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); 467 } else { 468 // TODO: handle more cases if we are using other x86 instructions 469 // that can generate SIGFPE signal on linux. 470 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op); 471 fatal("please update this code."); 472 } 473 #endif // AMD64 474 } else if (sig == SIGSEGV && 475 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) { 476 // Determination of interpreter/vtable stub/compiled code null exception 477 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); 478 } 479 } else if (thread->thread_state() == _thread_in_vm && 480 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */ 481 thread->doing_unsafe_access()) { 482 address next_pc = Assembler::locate_next_instruction(pc); 483 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 484 } 485 486 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in 487 // and the heap gets shrunk before the field access. 488 if ((sig == SIGSEGV) || (sig == SIGBUS)) { 489 address addr = JNI_FastGetField::find_slowcase_pc(pc); 490 if (addr != (address)-1) { 491 stub = addr; 492 } 493 } 494 495 // Check to see if we caught the safepoint code in the 496 // process of write protecting the memory serialization page. 497 // It write enables the page immediately after protecting it 498 // so we can just return to retry the write. 499 if ((sig == SIGSEGV) && 500 os::is_memory_serialize_page(thread, (address) info->si_addr)) { 501 // Block current thread until the memory serialize page permission restored. 502 os::block_on_serialize_page_trap(); 503 return true; 504 } 505 } 506 507 #ifndef AMD64 508 // Execution protection violation 509 // 510 // This should be kept as the last step in the triage. We don't 511 // have a dedicated trap number for a no-execute fault, so be 512 // conservative and allow other handlers the first shot. 513 // 514 // Note: We don't test that info->si_code == SEGV_ACCERR here. 515 // this si_code is so generic that it is almost meaningless; and 516 // the si_code for this condition may change in the future. 517 // Furthermore, a false-positive should be harmless. 518 if (UnguardOnExecutionViolation > 0 && 519 (sig == SIGSEGV || sig == SIGBUS) && 520 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) { 521 int page_size = os::vm_page_size(); 522 address addr = (address) info->si_addr; 523 address pc = os::Linux::ucontext_get_pc(uc); 524 // Make sure the pc and the faulting address are sane. 525 // 526 // If an instruction spans a page boundary, and the page containing 527 // the beginning of the instruction is executable but the following 528 // page is not, the pc and the faulting address might be slightly 529 // different - we still want to unguard the 2nd page in this case. 530 // 531 // 15 bytes seems to be a (very) safe value for max instruction size. 532 bool pc_is_near_addr = 533 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15); 534 bool instr_spans_page_boundary = 535 (align_size_down((intptr_t) pc ^ (intptr_t) addr, 536 (intptr_t) page_size) > 0); 537 538 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) { 539 static volatile address last_addr = 540 (address) os::non_memory_address_word(); 541 542 // In conservative mode, don't unguard unless the address is in the VM 543 if (addr != last_addr && 544 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) { 545 546 // Set memory to RWX and retry 547 address page_start = 548 (address) align_size_down((intptr_t) addr, (intptr_t) page_size); 549 bool res = os::protect_memory((char*) page_start, page_size, 550 os::MEM_PROT_RWX); 551 552 log_debug(os)("Execution protection violation " 553 "at " INTPTR_FORMAT 554 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr), 555 p2i(page_start), (res ? "success" : "failed"), errno); 556 stub = pc; 557 558 // Set last_addr so if we fault again at the same address, we don't end 559 // up in an endless loop. 560 // 561 // There are two potential complications here. Two threads trapping at 562 // the same address at the same time could cause one of the threads to 563 // think it already unguarded, and abort the VM. Likely very rare. 564 // 565 // The other race involves two threads alternately trapping at 566 // different addresses and failing to unguard the page, resulting in 567 // an endless loop. This condition is probably even more unlikely than 568 // the first. 569 // 570 // Although both cases could be avoided by using locks or thread local 571 // last_addr, these solutions are unnecessary complication: this 572 // handler is a best-effort safety net, not a complete solution. It is 573 // disabled by default and should only be used as a workaround in case 574 // we missed any no-execute-unsafe VM code. 575 576 last_addr = addr; 577 } 578 } 579 } 580 #endif // !AMD64 581 582 if (stub != NULL) { 583 // save all thread context in case we need to restore it 584 if (thread != NULL) thread->set_saved_exception_pc(pc); 585 586 os::Linux::ucontext_set_pc(uc, stub); 587 return true; 588 } 589 590 // signal-chaining 591 if (os::Linux::chained_handler(sig, info, ucVoid)) { 592 return true; 593 } 594 595 if (!abort_if_unrecognized) { 596 // caller wants another chance, so give it to him 597 return false; 598 } 599 600 if (pc == NULL && uc != NULL) { 601 pc = os::Linux::ucontext_get_pc(uc); 602 } 603 604 // unmask current signal 605 sigset_t newset; 606 sigemptyset(&newset); 607 sigaddset(&newset, sig); 608 sigprocmask(SIG_UNBLOCK, &newset, NULL); 609 610 VMError::report_and_die(t, sig, pc, info, ucVoid); 611 612 ShouldNotReachHere(); 613 return true; // Mute compiler 614 } 615 616 void os::Linux::init_thread_fpu_state(void) { 617 #ifndef AMD64 618 // set fpu to 53 bit precision 619 set_fpu_control_word(0x27f); 620 #endif // !AMD64 621 } 622 623 int os::Linux::get_fpu_control_word(void) { 624 #ifdef AMD64 625 return 0; 626 #else 627 int fpu_control; 628 _FPU_GETCW(fpu_control); 629 return fpu_control & 0xffff; 630 #endif // AMD64 631 } 632 633 void os::Linux::set_fpu_control_word(int fpu_control) { 634 #ifndef AMD64 635 _FPU_SETCW(fpu_control); 636 #endif // !AMD64 637 } 638 639 // Check that the linux kernel version is 2.4 or higher since earlier 640 // versions do not support SSE without patches. 641 bool os::supports_sse() { 642 #ifdef AMD64 643 return true; 644 #else 645 struct utsname uts; 646 if( uname(&uts) != 0 ) return false; // uname fails? 647 char *minor_string; 648 int major = strtol(uts.release,&minor_string,10); 649 int minor = strtol(minor_string+1,NULL,10); 650 bool result = (major > 2 || (major==2 && minor >= 4)); 651 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2", 652 major,minor, result ? "DOES" : "does NOT"); 653 return result; 654 #endif // AMD64 655 } 656 657 bool os::is_allocatable(size_t bytes) { 658 #ifdef AMD64 659 // unused on amd64? 660 return true; 661 #else 662 663 if (bytes < 2 * G) { 664 return true; 665 } 666 667 char* addr = reserve_memory(bytes, NULL); 668 669 if (addr != NULL) { 670 release_memory(addr, bytes); 671 } 672 673 return addr != NULL; 674 #endif // AMD64 675 } 676 677 //////////////////////////////////////////////////////////////////////////////// 678 // thread stack 679 680 #ifdef AMD64 681 size_t os::Posix::_compiler_thread_min_stack_allowed = 64 * K; 682 size_t os::Posix::_java_thread_min_stack_allowed = 64 * K; 683 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K; 684 #else 685 size_t os::Posix::_compiler_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K; 686 size_t os::Posix::_java_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K; 687 size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K; 688 #endif // AMD64 689 690 // return default stack size for thr_type 691 size_t os::Posix::default_stack_size(os::ThreadType thr_type) { 692 // default stack size (compiler thread needs larger stack) 693 #ifdef AMD64 694 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M); 695 #else 696 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K); 697 #endif // AMD64 698 return s; 699 } 700 701 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 702 // Creating guard page is very expensive. Java thread has HotSpot 703 // guard page, only enable glibc guard page for non-Java threads. 704 return (thr_type == java_thread ? 0 : page_size()); 705 } 706 707 // Java thread: 708 // 709 // Low memory addresses 710 // +------------------------+ 711 // | |\ JavaThread created by VM does not have glibc 712 // | glibc guard page | - guard, attached Java thread usually has 713 // | |/ 1 page glibc guard. 714 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 715 // | |\ 716 // | HotSpot Guard Pages | - red and yellow pages 717 // | |/ 718 // +------------------------+ JavaThread::stack_yellow_zone_base() 719 // | |\ 720 // | Normal Stack | - 721 // | |/ 722 // P2 +------------------------+ Thread::stack_base() 723 // 724 // Non-Java thread: 725 // 726 // Low memory addresses 727 // +------------------------+ 728 // | |\ 729 // | glibc guard page | - usually 1 page 730 // | |/ 731 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 732 // | |\ 733 // | Normal Stack | - 734 // | |/ 735 // P2 +------------------------+ Thread::stack_base() 736 // 737 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from 738 // pthread_attr_getstack() 739 740 static void current_stack_region(address * bottom, size_t * size) { 741 if (os::Linux::is_initial_thread()) { 742 // initial thread needs special handling because pthread_getattr_np() 743 // may return bogus value. 744 *bottom = os::Linux::initial_thread_stack_bottom(); 745 *size = os::Linux::initial_thread_stack_size(); 746 } else { 747 pthread_attr_t attr; 748 749 int rslt = pthread_getattr_np(pthread_self(), &attr); 750 751 // JVM needs to know exact stack location, abort if it fails 752 if (rslt != 0) { 753 if (rslt == ENOMEM) { 754 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 755 } else { 756 fatal("pthread_getattr_np failed with errno = %d", rslt); 757 } 758 } 759 760 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 761 fatal("Can not locate current stack attributes!"); 762 } 763 764 pthread_attr_destroy(&attr); 765 766 } 767 assert(os::current_stack_pointer() >= *bottom && 768 os::current_stack_pointer() < *bottom + *size, "just checking"); 769 } 770 771 address os::current_stack_base() { 772 address bottom; 773 size_t size; 774 current_stack_region(&bottom, &size); 775 return (bottom + size); 776 } 777 778 size_t os::current_stack_size() { 779 // stack size includes normal stack and HotSpot guard pages 780 address bottom; 781 size_t size; 782 current_stack_region(&bottom, &size); 783 return size; 784 } 785 786 ///////////////////////////////////////////////////////////////////////////// 787 // helper functions for fatal error handler 788 789 void os::print_context(outputStream *st, const void *context) { 790 if (context == NULL) return; 791 792 const ucontext_t *uc = (const ucontext_t*)context; 793 st->print_cr("Registers:"); 794 #ifdef AMD64 795 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]); 796 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]); 797 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]); 798 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]); 799 st->cr(); 800 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]); 801 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]); 802 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]); 803 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]); 804 st->cr(); 805 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]); 806 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]); 807 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]); 808 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]); 809 st->cr(); 810 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]); 811 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]); 812 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]); 813 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]); 814 st->cr(); 815 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]); 816 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]); 817 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]); 818 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]); 819 st->cr(); 820 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]); 821 #else 822 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]); 823 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]); 824 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]); 825 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]); 826 st->cr(); 827 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]); 828 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]); 829 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]); 830 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]); 831 st->cr(); 832 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]); 833 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]); 834 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2); 835 #endif // AMD64 836 st->cr(); 837 st->cr(); 838 839 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc); 840 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp)); 841 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t)); 842 st->cr(); 843 844 // Note: it may be unsafe to inspect memory near pc. For example, pc may 845 // point to garbage if entry point in an nmethod is corrupted. Leave 846 // this at the end, and hope for the best. 847 address pc = os::Linux::ucontext_get_pc(uc); 848 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc)); 849 print_hex_dump(st, pc - 32, pc + 32, sizeof(char)); 850 } 851 852 void os::print_register_info(outputStream *st, const void *context) { 853 if (context == NULL) return; 854 855 const ucontext_t *uc = (const ucontext_t*)context; 856 857 st->print_cr("Register to memory mapping:"); 858 st->cr(); 859 860 // this is horrendously verbose but the layout of the registers in the 861 // context does not match how we defined our abstract Register set, so 862 // we can't just iterate through the gregs area 863 864 // this is only for the "general purpose" registers 865 866 #ifdef AMD64 867 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]); 868 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]); 869 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]); 870 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]); 871 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]); 872 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]); 873 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]); 874 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]); 875 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]); 876 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]); 877 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]); 878 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]); 879 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]); 880 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]); 881 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]); 882 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]); 883 #else 884 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]); 885 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]); 886 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]); 887 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]); 888 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]); 889 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]); 890 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]); 891 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]); 892 #endif // AMD64 893 894 st->cr(); 895 } 896 897 void os::setup_fpu() { 898 #ifndef AMD64 899 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std(); 900 __asm__ volatile ( "fldcw (%0)" : 901 : "r" (fpu_cntrl) : "memory"); 902 #endif // !AMD64 903 } 904 905 #ifndef PRODUCT 906 void os::verify_stack_alignment() { 907 #ifdef AMD64 908 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment"); 909 #endif 910 } 911 #endif 912 913 914 /* 915 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit 916 * updates (JDK-8023956). 917 */ 918 void os::workaround_expand_exec_shield_cs_limit() { 919 #if defined(IA32) 920 size_t page_size = os::vm_page_size(); 921 /* 922 * Take the highest VA the OS will give us and exec 923 * 924 * Although using -(pagesz) as mmap hint works on newer kernel as you would 925 * think, older variants affected by this work-around don't (search forward only). 926 * 927 * On the affected distributions, we understand the memory layout to be: 928 * 929 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT. 930 * 931 * A few pages south main stack will do it. 932 * 933 * If we are embedded in an app other than launcher (initial != main stack), 934 * we don't have much control or understanding of the address space, just let it slide. 935 */ 936 char* hint = (char*)(Linux::initial_thread_stack_bottom() - 937 (JavaThread::stack_guard_zone_size() + page_size)); 938 char* codebuf = os::attempt_reserve_memory_at(page_size, hint); 939 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) { 940 return; // No matter, we tried, best effort. 941 } 942 943 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal); 944 945 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf); 946 947 // Some code to exec: the 'ret' instruction 948 codebuf[0] = 0xC3; 949 950 // Call the code in the codebuf 951 __asm__ volatile("call *%0" : : "r"(codebuf)); 952 953 // keep the page mapped so CS limit isn't reduced. 954 #endif 955 } 956 957 int os::extra_bang_size_in_bytes() { 958 // JDK-8050147 requires the full cache line bang for x86. 959 return VM_Version::L1_line_size(); 960 }