1/* 2 * Copyright (c) 1999, 2017, 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/align.hpp" 54#include "utilities/events.hpp" 55#include "utilities/vmError.hpp" 56 57// put OS-includes here 58# include <sys/types.h> 59# include <sys/mman.h> 60# include <pthread.h> 61# include <signal.h> 62# include <errno.h> 63# include <dlfcn.h> 64# include <stdlib.h> 65# include <stdio.h> 66# include <unistd.h> 67# include <sys/resource.h> 68# include <pthread.h> 69# include <sys/stat.h> 70# include <sys/time.h> 71# include <sys/utsname.h> 72# include <sys/socket.h> 73# include <sys/wait.h> 74# include <pwd.h> 75# include <poll.h> 76# include <ucontext.h> 77#ifndef AMD64 78# include <fpu_control.h> 79#endif 80 81#ifdef AMD64 82#define REG_SP REG_RSP 83#define REG_PC REG_RIP 84#define REG_FP REG_RBP 85#define SPELL_REG_SP "rsp" 86#define SPELL_REG_FP "rbp" 87#else 88#define REG_SP REG_UESP 89#define REG_PC REG_EIP 90#define REG_FP REG_EBP 91#define SPELL_REG_SP "esp" 92#define SPELL_REG_FP "ebp" 93#endif // AMD64 94 95address os::current_stack_pointer() { 96#ifdef SPARC_WORKS 97 register void *esp; 98 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp)); 99 return (address) ((char*)esp + sizeof(long)*2); 100#elif defined(__clang__) 101 intptr_t* esp; 102 __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):); 103 return (address) esp; 104#else 105 register void *esp __asm__ (SPELL_REG_SP); 106 return (address) esp; 107#endif 108} 109 110char* os::non_memory_address_word() { 111 // Must never look like an address returned by reserve_memory, 112 // even in its subfields (as defined by the CPU immediate fields, 113 // if the CPU splits constants across multiple instructions). 114 115 return (char*) -1; 116} 117 118void os::initialize_thread(Thread* thr) { 119// Nothing to do. 120} 121 122address os::Linux::ucontext_get_pc(const ucontext_t * uc) { 123 return (address)uc->uc_mcontext.gregs[REG_PC]; 124} 125 126void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) { 127 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc; 128} 129 130intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) { 131 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP]; 132} 133 134intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) { 135 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP]; 136} 137 138// For Forte Analyzer AsyncGetCallTrace profiling support - thread 139// is currently interrupted by SIGPROF. 140// os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal 141// frames. Currently we don't do that on Linux, so it's the same as 142// os::fetch_frame_from_context(). 143// This method is also used for stack overflow signal handling. 144ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread, 145 const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) { 146 147 assert(thread != NULL, "just checking"); 148 assert(ret_sp != NULL, "just checking"); 149 assert(ret_fp != NULL, "just checking"); 150 151 return os::fetch_frame_from_context(uc, ret_sp, ret_fp); 152} 153 154ExtendedPC os::fetch_frame_from_context(const void* ucVoid, 155 intptr_t** ret_sp, intptr_t** ret_fp) { 156 157 ExtendedPC epc; 158 const ucontext_t* uc = (const ucontext_t*)ucVoid; 159 160 if (uc != NULL) { 161 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc)); 162 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc); 163 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc); 164 } else { 165 // construct empty ExtendedPC for return value checking 166 epc = ExtendedPC(NULL); 167 if (ret_sp) *ret_sp = (intptr_t *)NULL; 168 if (ret_fp) *ret_fp = (intptr_t *)NULL; 169 } 170 171 return epc; 172} 173 174frame os::fetch_frame_from_context(const void* ucVoid) { 175 intptr_t* sp; 176 intptr_t* fp; 177 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp); 178 return frame(sp, fp, epc.pc()); 179} 180 181frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) { 182 intptr_t* sp; 183 intptr_t* fp; 184 ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp); 185 return frame(sp, fp, epc.pc()); 186} 187 188bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) { 189 address pc = (address) os::Linux::ucontext_get_pc(uc); 190 if (Interpreter::contains(pc)) { 191 // interpreter performs stack banging after the fixed frame header has 192 // been generated while the compilers perform it before. To maintain 193 // semantic consistency between interpreted and compiled frames, the 194 // method returns the Java sender of the current frame. 195 *fr = os::fetch_frame_from_ucontext(thread, uc); 196 if (!fr->is_first_java_frame()) { 197 // get_frame_at_stack_banging_point() is only called when we 198 // have well defined stacks so java_sender() calls do not need 199 // to assert safe_for_sender() first. 200 *fr = fr->java_sender(); 201 } 202 } else { 203 // more complex code with compiled code 204 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above"); 205 CodeBlob* cb = CodeCache::find_blob(pc); 206 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) { 207 // Not sure where the pc points to, fallback to default 208 // stack overflow handling 209 return false; 210 } else { 211 // in compiled code, the stack banging is performed just after the return pc 212 // has been pushed on the stack 213 intptr_t* fp = os::Linux::ucontext_get_fp(uc); 214 intptr_t* sp = os::Linux::ucontext_get_sp(uc); 215 *fr = frame(sp + 1, fp, (address)*sp); 216 if (!fr->is_java_frame()) { 217 assert(!fr->is_first_frame(), "Safety check"); 218 // See java_sender() comment above. 219 *fr = fr->java_sender(); 220 } 221 } 222 } 223 assert(fr->is_java_frame(), "Safety check"); 224 return true; 225} 226 227// By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get 228// turned off by -fomit-frame-pointer, 229frame os::get_sender_for_C_frame(frame* fr) { 230 return frame(fr->sender_sp(), fr->link(), fr->sender_pc()); 231} 232 233intptr_t* _get_previous_fp() { 234#ifdef SPARC_WORKS 235 register intptr_t **ebp; 236 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp)); 237#elif defined(__clang__) 238 intptr_t **ebp; 239 __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):); 240#else 241 register intptr_t **ebp __asm__ (SPELL_REG_FP); 242#endif 243 // ebp is for this frame (_get_previous_fp). We want the ebp for the 244 // caller of os::current_frame*(), so go up two frames. However, for 245 // optimized builds, _get_previous_fp() will be inlined, so only go 246 // up 1 frame in that case. 247#ifdef _NMT_NOINLINE_ 248 return **(intptr_t***)ebp; 249#else 250 return *ebp; 251#endif 252} 253 254 255frame os::current_frame() { 256 intptr_t* fp = _get_previous_fp(); 257 frame myframe((intptr_t*)os::current_stack_pointer(), 258 (intptr_t*)fp, 259 CAST_FROM_FN_PTR(address, os::current_frame)); 260 if (os::is_first_C_frame(&myframe)) { 261 // stack is not walkable 262 return frame(); 263 } else { 264 return os::get_sender_for_C_frame(&myframe); 265 } 266} 267 268// Utility functions 269 270// From IA32 System Programming Guide 271enum { 272 trap_page_fault = 0xE 273}; 274 275extern "C" JNIEXPORT int 276JVM_handle_linux_signal(int sig, 277 siginfo_t* info, 278 void* ucVoid, 279 int abort_if_unrecognized) { 280 ucontext_t* uc = (ucontext_t*) ucVoid; 281 282 Thread* t = Thread::current_or_null_safe(); 283 284 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away 285 // (no destructors can be run) 286 os::ThreadCrashProtection::check_crash_protection(sig, t); 287 288 SignalHandlerMark shm(t); 289 290 // Note: it's not uncommon that JNI code uses signal/sigset to install 291 // then restore certain signal handler (e.g. to temporarily block SIGPIPE, 292 // or have a SIGILL handler when detecting CPU type). When that happens, 293 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To 294 // avoid unnecessary crash when libjsig is not preloaded, try handle signals 295 // that do not require siginfo/ucontext first. 296 297 if (sig == SIGPIPE || sig == SIGXFSZ) { 298 // allow chained handler to go first 299 if (os::Linux::chained_handler(sig, info, ucVoid)) { 300 return true; 301 } else { 302 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219 303 return true; 304 } 305 } 306 307 JavaThread* thread = NULL; 308 VMThread* vmthread = NULL; 309 if (os::Linux::signal_handlers_are_installed) { 310 if (t != NULL ){ 311 if(t->is_Java_thread()) { 312 thread = (JavaThread*)t; 313 } 314 else if(t->is_VM_thread()){ 315 vmthread = (VMThread *)t; 316 } 317 } 318 } 319/* 320 NOTE: does not seem to work on linux. 321 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) { 322 // can't decode this kind of signal 323 info = NULL; 324 } else { 325 assert(sig == info->si_signo, "bad siginfo"); 326 } 327*/ 328 // decide if this trap can be handled by a stub 329 address stub = NULL; 330 331 address pc = NULL; 332 333 //%note os_trap_1 334 if (info != NULL && uc != NULL && thread != NULL) { 335 pc = (address) os::Linux::ucontext_get_pc(uc); 336 337 if (StubRoutines::is_safefetch_fault(pc)) { 338 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc)); 339 return 1; 340 } 341 342#ifndef AMD64 343 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs 344 // This can happen in any running code (currently more frequently in 345 // interpreter code but has been seen in compiled code) 346 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) { 347 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due " 348 "to unstable signal handling in this distribution."); 349 } 350#endif // AMD64 351 352 // Handle ALL stack overflow variations here 353 if (sig == SIGSEGV) { 354 address addr = (address) info->si_addr; 355 356 // check if fault address is within thread stack 357 if (thread->on_local_stack(addr)) { 358 // stack overflow 359 if (thread->in_stack_yellow_reserved_zone(addr)) { 360 if (thread->thread_state() == _thread_in_Java) { 361 if (thread->in_stack_reserved_zone(addr)) { 362 frame fr; 363 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) { 364 assert(fr.is_java_frame(), "Must be a Java frame"); 365 frame activation = 366 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr); 367 if (activation.sp() != NULL) { 368 thread->disable_stack_reserved_zone(); 369 if (activation.is_interpreted_frame()) { 370 thread->set_reserved_stack_activation((address)( 371 activation.fp() + frame::interpreter_frame_initial_sp_offset)); 372 } else { 373 thread->set_reserved_stack_activation((address)activation.unextended_sp()); 374 } 375 return 1; 376 } 377 } 378 } 379 // Throw a stack overflow exception. Guard pages will be reenabled 380 // while unwinding the stack. 381 thread->disable_stack_yellow_reserved_zone(); 382 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW); 383 } else { 384 // Thread was in the vm or native code. Return and try to finish. 385 thread->disable_stack_yellow_reserved_zone(); 386 return 1; 387 } 388 } else if (thread->in_stack_red_zone(addr)) { 389 // Fatal red zone violation. Disable the guard pages and fall through 390 // to handle_unexpected_exception way down below. 391 thread->disable_stack_red_zone(); 392 tty->print_raw_cr("An irrecoverable stack overflow has occurred."); 393 394 // This is a likely cause, but hard to verify. Let's just print 395 // it as a hint. 396 tty->print_raw_cr("Please check if any of your loaded .so files has " 397 "enabled executable stack (see man page execstack(8))"); 398 } else { 399 // Accessing stack address below sp may cause SEGV if current 400 // thread has MAP_GROWSDOWN stack. This should only happen when 401 // current thread was created by user code with MAP_GROWSDOWN flag 402 // and then attached to VM. See notes in os_linux.cpp. 403 if (thread->osthread()->expanding_stack() == 0) { 404 thread->osthread()->set_expanding_stack(); 405 if (os::Linux::manually_expand_stack(thread, addr)) { 406 thread->osthread()->clear_expanding_stack(); 407 return 1; 408 } 409 thread->osthread()->clear_expanding_stack(); 410 } else { 411 fatal("recursive segv. expanding stack."); 412 } 413 } 414 } 415 } 416 417 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) { 418 // Verify that OS save/restore AVX registers. 419 stub = VM_Version::cpuinfo_cont_addr(); 420 } 421 422 if (thread->thread_state() == _thread_in_Java) { 423 // Java thread running in Java code => find exception handler if any 424 // a fault inside compiled code, the interpreter, or a stub 425 426 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) { 427 stub = SharedRuntime::get_poll_stub(pc); 428 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) { 429 // BugId 4454115: A read from a MappedByteBuffer can fault 430 // here if the underlying file has been truncated. 431 // Do not crash the VM in such a case. 432 CodeBlob* cb = CodeCache::find_blob_unsafe(pc); 433 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL; 434 if (nm != NULL && nm->has_unsafe_access()) { 435 address next_pc = Assembler::locate_next_instruction(pc); 436 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 437 } 438 } 439 else 440 441#ifdef AMD64 442 if (sig == SIGFPE && 443 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) { 444 stub = 445 SharedRuntime:: 446 continuation_for_implicit_exception(thread, 447 pc, 448 SharedRuntime:: 449 IMPLICIT_DIVIDE_BY_ZERO); 450#else 451 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) { 452 // HACK: si_code does not work on linux 2.2.12-20!!! 453 int op = pc[0]; 454 if (op == 0xDB) { 455 // FIST 456 // TODO: The encoding of D2I in i486.ad can cause an exception 457 // prior to the fist instruction if there was an invalid operation 458 // pending. We want to dismiss that exception. From the win_32 459 // side it also seems that if it really was the fist causing 460 // the exception that we do the d2i by hand with different 461 // rounding. Seems kind of weird. 462 // NOTE: that we take the exception at the NEXT floating point instruction. 463 assert(pc[0] == 0xDB, "not a FIST opcode"); 464 assert(pc[1] == 0x14, "not a FIST opcode"); 465 assert(pc[2] == 0x24, "not a FIST opcode"); 466 return true; 467 } else if (op == 0xF7) { 468 // IDIV 469 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); 470 } else { 471 // TODO: handle more cases if we are using other x86 instructions 472 // that can generate SIGFPE signal on linux. 473 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op); 474 fatal("please update this code."); 475 } 476#endif // AMD64 477 } else if (sig == SIGSEGV && 478 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) { 479 // Determination of interpreter/vtable stub/compiled code null exception 480 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); 481 } 482 } else if (thread->thread_state() == _thread_in_vm && 483 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */ 484 thread->doing_unsafe_access()) { 485 address next_pc = Assembler::locate_next_instruction(pc); 486 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 487 } 488 489 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in 490 // and the heap gets shrunk before the field access. 491 if ((sig == SIGSEGV) || (sig == SIGBUS)) { 492 address addr = JNI_FastGetField::find_slowcase_pc(pc); 493 if (addr != (address)-1) { 494 stub = addr; 495 } 496 } 497 498 // Check to see if we caught the safepoint code in the 499 // process of write protecting the memory serialization page. 500 // It write enables the page immediately after protecting it 501 // so we can just return to retry the write. 502 if ((sig == SIGSEGV) && 503 os::is_memory_serialize_page(thread, (address) info->si_addr)) { 504 // Block current thread until the memory serialize page permission restored. 505 os::block_on_serialize_page_trap(); 506 return true; 507 } 508 } 509 510#ifndef AMD64 511 // Execution protection violation 512 // 513 // This should be kept as the last step in the triage. We don't 514 // have a dedicated trap number for a no-execute fault, so be 515 // conservative and allow other handlers the first shot. 516 // 517 // Note: We don't test that info->si_code == SEGV_ACCERR here. 518 // this si_code is so generic that it is almost meaningless; and 519 // the si_code for this condition may change in the future. 520 // Furthermore, a false-positive should be harmless. 521 if (UnguardOnExecutionViolation > 0 && 522 (sig == SIGSEGV || sig == SIGBUS) && 523 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) { 524 int page_size = os::vm_page_size(); 525 address addr = (address) info->si_addr; 526 address pc = os::Linux::ucontext_get_pc(uc); 527 // Make sure the pc and the faulting address are sane. 528 // 529 // If an instruction spans a page boundary, and the page containing 530 // the beginning of the instruction is executable but the following 531 // page is not, the pc and the faulting address might be slightly 532 // different - we still want to unguard the 2nd page in this case. 533 // 534 // 15 bytes seems to be a (very) safe value for max instruction size. 535 bool pc_is_near_addr = 536 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15); 537 bool instr_spans_page_boundary = 538 (align_down((intptr_t) pc ^ (intptr_t) addr, 539 (intptr_t) page_size) > 0); 540 541 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) { 542 static volatile address last_addr = 543 (address) os::non_memory_address_word(); 544 545 // In conservative mode, don't unguard unless the address is in the VM 546 if (addr != last_addr && 547 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) { 548 549 // Set memory to RWX and retry 550 address page_start = align_down(addr, page_size); 551 bool res = os::protect_memory((char*) page_start, page_size, 552 os::MEM_PROT_RWX); 553 554 log_debug(os)("Execution protection violation " 555 "at " INTPTR_FORMAT 556 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr), 557 p2i(page_start), (res ? "success" : "failed"), errno); 558 stub = pc; 559 560 // Set last_addr so if we fault again at the same address, we don't end 561 // up in an endless loop. 562 // 563 // There are two potential complications here. Two threads trapping at 564 // the same address at the same time could cause one of the threads to 565 // think it already unguarded, and abort the VM. Likely very rare. 566 // 567 // The other race involves two threads alternately trapping at 568 // different addresses and failing to unguard the page, resulting in 569 // an endless loop. This condition is probably even more unlikely than 570 // the first. 571 // 572 // Although both cases could be avoided by using locks or thread local 573 // last_addr, these solutions are unnecessary complication: this 574 // handler is a best-effort safety net, not a complete solution. It is 575 // disabled by default and should only be used as a workaround in case 576 // we missed any no-execute-unsafe VM code. 577 578 last_addr = addr; 579 } 580 } 581 } 582#endif // !AMD64 583 584 if (stub != NULL) { 585 // save all thread context in case we need to restore it 586 if (thread != NULL) thread->set_saved_exception_pc(pc); 587 588 os::Linux::ucontext_set_pc(uc, stub); 589 return true; 590 } 591 592 // signal-chaining 593 if (os::Linux::chained_handler(sig, info, ucVoid)) { 594 return true; 595 } 596 597 if (!abort_if_unrecognized) { 598 // caller wants another chance, so give it to him 599 return false; 600 } 601 602 if (pc == NULL && uc != NULL) { 603 pc = os::Linux::ucontext_get_pc(uc); 604 } 605 606 // unmask current signal 607 sigset_t newset; 608 sigemptyset(&newset); 609 sigaddset(&newset, sig); 610 sigprocmask(SIG_UNBLOCK, &newset, NULL); 611 612 VMError::report_and_die(t, sig, pc, info, ucVoid); 613 614 ShouldNotReachHere(); 615 return true; // Mute compiler 616} 617 618void os::Linux::init_thread_fpu_state(void) { 619#ifndef AMD64 620 // set fpu to 53 bit precision 621 set_fpu_control_word(0x27f); 622#endif // !AMD64 623} 624 625int os::Linux::get_fpu_control_word(void) { 626#ifdef AMD64 627 return 0; 628#else 629 int fpu_control; 630 _FPU_GETCW(fpu_control); 631 return fpu_control & 0xffff; 632#endif // AMD64 633} 634 635void os::Linux::set_fpu_control_word(int fpu_control) { 636#ifndef AMD64 637 _FPU_SETCW(fpu_control); 638#endif // !AMD64 639} 640 641// Check that the linux kernel version is 2.4 or higher since earlier 642// versions do not support SSE without patches. 643bool os::supports_sse() { 644#ifdef AMD64 645 return true; 646#else 647 struct utsname uts; 648 if( uname(&uts) != 0 ) return false; // uname fails? 649 char *minor_string; 650 int major = strtol(uts.release,&minor_string,10); 651 int minor = strtol(minor_string+1,NULL,10); 652 bool result = (major > 2 || (major==2 && minor >= 4)); 653 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2", 654 major,minor, result ? "DOES" : "does NOT"); 655 return result; 656#endif // AMD64 657} 658 659bool os::is_allocatable(size_t bytes) { 660#ifdef AMD64 661 // unused on amd64? 662 return true; 663#else 664 665 if (bytes < 2 * G) { 666 return true; 667 } 668 669 char* addr = reserve_memory(bytes, NULL); 670 671 if (addr != NULL) { 672 release_memory(addr, bytes); 673 } 674 675 return addr != NULL; 676#endif // AMD64 677} 678 679//////////////////////////////////////////////////////////////////////////////// 680// thread stack 681 682// Minimum usable stack sizes required to get to user code. Space for 683// HotSpot guard pages is added later. 684size_t os::Posix::_compiler_thread_min_stack_allowed = 48 * K; 685size_t os::Posix::_java_thread_min_stack_allowed = 40 * K; 686#ifdef _LP64 687size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K; 688#else 689size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K; 690#endif // _LP64 691 692// return default stack size for thr_type 693size_t os::Posix::default_stack_size(os::ThreadType thr_type) { 694 // default stack size (compiler thread needs larger stack) 695#ifdef AMD64 696 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M); 697#else 698 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K); 699#endif // AMD64 700 return s; 701} 702 703///////////////////////////////////////////////////////////////////////////// 704// helper functions for fatal error handler 705 706void os::print_context(outputStream *st, const void *context) { 707 if (context == NULL) return; 708 709 const ucontext_t *uc = (const ucontext_t*)context; 710 st->print_cr("Registers:"); 711#ifdef AMD64 712 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]); 713 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]); 714 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]); 715 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]); 716 st->cr(); 717 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]); 718 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]); 719 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]); 720 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]); 721 st->cr(); 722 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]); 723 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]); 724 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]); 725 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]); 726 st->cr(); 727 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]); 728 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]); 729 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]); 730 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]); 731 st->cr(); 732 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]); 733 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]); 734 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]); 735 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]); 736 st->cr(); 737 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]); 738#else 739 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]); 740 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]); 741 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]); 742 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]); 743 st->cr(); 744 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]); 745 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]); 746 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]); 747 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]); 748 st->cr(); 749 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]); 750 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]); 751 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2); 752#endif // AMD64 753 st->cr(); 754 st->cr(); 755 756 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc); 757 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp)); 758 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t)); 759 st->cr(); 760 761 // Note: it may be unsafe to inspect memory near pc. For example, pc may 762 // point to garbage if entry point in an nmethod is corrupted. Leave 763 // this at the end, and hope for the best. 764 address pc = os::Linux::ucontext_get_pc(uc); 765 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc)); 766 print_hex_dump(st, pc - 32, pc + 32, sizeof(char)); 767} 768 769void os::print_register_info(outputStream *st, const void *context) { 770 if (context == NULL) return; 771 772 const ucontext_t *uc = (const ucontext_t*)context; 773 774 st->print_cr("Register to memory mapping:"); 775 st->cr(); 776 777 // this is horrendously verbose but the layout of the registers in the 778 // context does not match how we defined our abstract Register set, so 779 // we can't just iterate through the gregs area 780 781 // this is only for the "general purpose" registers 782 783#ifdef AMD64 784 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]); 785 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]); 786 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]); 787 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]); 788 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]); 789 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]); 790 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]); 791 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]); 792 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]); 793 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]); 794 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]); 795 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]); 796 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]); 797 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]); 798 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]); 799 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]); 800#else 801 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]); 802 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]); 803 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]); 804 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]); 805 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]); 806 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]); 807 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]); 808 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]); 809#endif // AMD64 810 811 st->cr(); 812} 813 814void os::setup_fpu() { 815#ifndef AMD64 816 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std(); 817 __asm__ volatile ( "fldcw (%0)" : 818 : "r" (fpu_cntrl) : "memory"); 819#endif // !AMD64 820} 821 822#ifndef PRODUCT 823void os::verify_stack_alignment() { 824#ifdef AMD64 825 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment"); 826#endif 827} 828#endif 829 830 831/* 832 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit 833 * updates (JDK-8023956). 834 */ 835void os::workaround_expand_exec_shield_cs_limit() { 836#if defined(IA32) 837 size_t page_size = os::vm_page_size(); 838 /* 839 * Take the highest VA the OS will give us and exec 840 * 841 * Although using -(pagesz) as mmap hint works on newer kernel as you would 842 * think, older variants affected by this work-around don't (search forward only). 843 * 844 * On the affected distributions, we understand the memory layout to be: 845 * 846 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT. 847 * 848 * A few pages south main stack will do it. 849 * 850 * If we are embedded in an app other than launcher (initial != main stack), 851 * we don't have much control or understanding of the address space, just let it slide. 852 */ 853 char* hint = (char*)(Linux::initial_thread_stack_bottom() - 854 (JavaThread::stack_guard_zone_size() + page_size)); 855 char* codebuf = os::attempt_reserve_memory_at(page_size, hint); 856 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) { 857 return; // No matter, we tried, best effort. 858 } 859 860 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal); 861 862 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf); 863 864 // Some code to exec: the 'ret' instruction 865 codebuf[0] = 0xC3; 866 867 // Call the code in the codebuf 868 __asm__ volatile("call *%0" : : "r"(codebuf)); 869 870 // keep the page mapped so CS limit isn't reduced. 871#endif 872} 873 874int os::extra_bang_size_in_bytes() { 875 // JDK-8050147 requires the full cache line bang for x86. 876 return VM_Version::L1_line_size(); 877} 878