os_linux_x86.cpp revision 11120:f2916653b884
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 "mutex_linux.inline.hpp" 37#include "os_share_linux.hpp" 38#include "prims/jniFastGetField.hpp" 39#include "prims/jvm.h" 40#include "prims/jvm_misc.hpp" 41#include "runtime/arguments.hpp" 42#include "runtime/extendedPC.hpp" 43#include "runtime/frame.inline.hpp" 44#include "runtime/interfaceSupport.hpp" 45#include "runtime/java.hpp" 46#include "runtime/javaCalls.hpp" 47#include "runtime/mutexLocker.hpp" 48#include "runtime/osThread.hpp" 49#include "runtime/sharedRuntime.hpp" 50#include "runtime/stubRoutines.hpp" 51#include "runtime/thread.inline.hpp" 52#include "runtime/timer.hpp" 53#include "services/memTracker.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# include <fpu_control.h> 78 79#ifdef AMD64 80#define REG_SP REG_RSP 81#define REG_PC REG_RIP 82#define REG_FP REG_RBP 83#define SPELL_REG_SP "rsp" 84#define SPELL_REG_FP "rbp" 85#else 86#define REG_SP REG_UESP 87#define REG_PC REG_EIP 88#define REG_FP REG_EBP 89#define SPELL_REG_SP "esp" 90#define SPELL_REG_FP "ebp" 91#endif // AMD64 92 93address os::current_stack_pointer() { 94#ifdef SPARC_WORKS 95 register void *esp; 96 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp)); 97 return (address) ((char*)esp + sizeof(long)*2); 98#elif defined(__clang__) 99 intptr_t* esp; 100 __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):); 101 return (address) esp; 102#else 103 register void *esp __asm__ (SPELL_REG_SP); 104 return (address) esp; 105#endif 106} 107 108char* os::non_memory_address_word() { 109 // Must never look like an address returned by reserve_memory, 110 // even in its subfields (as defined by the CPU immediate fields, 111 // if the CPU splits constants across multiple instructions). 112 113 return (char*) -1; 114} 115 116void os::initialize_thread(Thread* thr) { 117// Nothing to do. 118} 119 120address os::Linux::ucontext_get_pc(const ucontext_t * uc) { 121 return (address)uc->uc_mcontext.gregs[REG_PC]; 122} 123 124void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) { 125 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc; 126} 127 128intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) { 129 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP]; 130} 131 132intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) { 133 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP]; 134} 135 136// For Forte Analyzer AsyncGetCallTrace profiling support - thread 137// is currently interrupted by SIGPROF. 138// os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal 139// frames. Currently we don't do that on Linux, so it's the same as 140// os::fetch_frame_from_context(). 141// This method is also used for stack overflow signal handling. 142ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread, 143 const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) { 144 145 assert(thread != NULL, "just checking"); 146 assert(ret_sp != NULL, "just checking"); 147 assert(ret_fp != NULL, "just checking"); 148 149 return os::fetch_frame_from_context(uc, ret_sp, ret_fp); 150} 151 152ExtendedPC os::fetch_frame_from_context(const void* ucVoid, 153 intptr_t** ret_sp, intptr_t** ret_fp) { 154 155 ExtendedPC epc; 156 const ucontext_t* uc = (const ucontext_t*)ucVoid; 157 158 if (uc != NULL) { 159 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc)); 160 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc); 161 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc); 162 } else { 163 // construct empty ExtendedPC for return value checking 164 epc = ExtendedPC(NULL); 165 if (ret_sp) *ret_sp = (intptr_t *)NULL; 166 if (ret_fp) *ret_fp = (intptr_t *)NULL; 167 } 168 169 return epc; 170} 171 172frame os::fetch_frame_from_context(const void* ucVoid) { 173 intptr_t* sp; 174 intptr_t* fp; 175 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp); 176 return frame(sp, fp, epc.pc()); 177} 178 179frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) { 180 intptr_t* sp; 181 intptr_t* fp; 182 ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp); 183 return frame(sp, fp, epc.pc()); 184} 185 186bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) { 187 address pc = (address) os::Linux::ucontext_get_pc(uc); 188 if (Interpreter::contains(pc)) { 189 // interpreter performs stack banging after the fixed frame header has 190 // been generated while the compilers perform it before. To maintain 191 // semantic consistency between interpreted and compiled frames, the 192 // method returns the Java sender of the current frame. 193 *fr = os::fetch_frame_from_ucontext(thread, uc); 194 if (!fr->is_first_java_frame()) { 195 assert(fr->safe_for_sender(thread), "Safety check"); 196 *fr = fr->java_sender(); 197 } 198 } else { 199 // more complex code with compiled code 200 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above"); 201 CodeBlob* cb = CodeCache::find_blob(pc); 202 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) { 203 // Not sure where the pc points to, fallback to default 204 // stack overflow handling 205 return false; 206 } else { 207 // in compiled code, the stack banging is performed just after the return pc 208 // has been pushed on the stack 209 intptr_t* fp = os::Linux::ucontext_get_fp(uc); 210 intptr_t* sp = os::Linux::ucontext_get_sp(uc); 211 *fr = frame(sp + 1, fp, (address)*sp); 212 if (!fr->is_java_frame()) { 213 assert(fr->safe_for_sender(thread), "Safety check"); 214 assert(!fr->is_first_frame(), "Safety check"); 215 *fr = fr->java_sender(); 216 } 217 } 218 } 219 assert(fr->is_java_frame(), "Safety check"); 220 return true; 221} 222 223// By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get 224// turned off by -fomit-frame-pointer, 225frame os::get_sender_for_C_frame(frame* fr) { 226 return frame(fr->sender_sp(), fr->link(), fr->sender_pc()); 227} 228 229intptr_t* _get_previous_fp() { 230#ifdef SPARC_WORKS 231 register intptr_t **ebp; 232 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp)); 233#elif defined(__clang__) 234 intptr_t **ebp; 235 __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):); 236#else 237 register intptr_t **ebp __asm__ (SPELL_REG_FP); 238#endif 239 return (intptr_t*) *ebp; // we want what it points to. 240} 241 242 243frame os::current_frame() { 244 intptr_t* fp = _get_previous_fp(); 245 frame myframe((intptr_t*)os::current_stack_pointer(), 246 (intptr_t*)fp, 247 CAST_FROM_FN_PTR(address, os::current_frame)); 248 if (os::is_first_C_frame(&myframe)) { 249 // stack is not walkable 250 return frame(); 251 } else { 252 return os::get_sender_for_C_frame(&myframe); 253 } 254} 255 256// Utility functions 257 258// From IA32 System Programming Guide 259enum { 260 trap_page_fault = 0xE 261}; 262 263extern "C" JNIEXPORT int 264JVM_handle_linux_signal(int sig, 265 siginfo_t* info, 266 void* ucVoid, 267 int abort_if_unrecognized) { 268 ucontext_t* uc = (ucontext_t*) ucVoid; 269 270 Thread* t = Thread::current_or_null_safe(); 271 272 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away 273 // (no destructors can be run) 274 os::WatcherThreadCrashProtection::check_crash_protection(sig, t); 275 276 SignalHandlerMark shm(t); 277 278 // Note: it's not uncommon that JNI code uses signal/sigset to install 279 // then restore certain signal handler (e.g. to temporarily block SIGPIPE, 280 // or have a SIGILL handler when detecting CPU type). When that happens, 281 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To 282 // avoid unnecessary crash when libjsig is not preloaded, try handle signals 283 // that do not require siginfo/ucontext first. 284 285 if (sig == SIGPIPE || sig == SIGXFSZ) { 286 // allow chained handler to go first 287 if (os::Linux::chained_handler(sig, info, ucVoid)) { 288 return true; 289 } else { 290 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219 291 return true; 292 } 293 } 294 295 JavaThread* thread = NULL; 296 VMThread* vmthread = NULL; 297 if (os::Linux::signal_handlers_are_installed) { 298 if (t != NULL ){ 299 if(t->is_Java_thread()) { 300 thread = (JavaThread*)t; 301 } 302 else if(t->is_VM_thread()){ 303 vmthread = (VMThread *)t; 304 } 305 } 306 } 307/* 308 NOTE: does not seem to work on linux. 309 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) { 310 // can't decode this kind of signal 311 info = NULL; 312 } else { 313 assert(sig == info->si_signo, "bad siginfo"); 314 } 315*/ 316 // decide if this trap can be handled by a stub 317 address stub = NULL; 318 319 address pc = NULL; 320 321 //%note os_trap_1 322 if (info != NULL && uc != NULL && thread != NULL) { 323 pc = (address) os::Linux::ucontext_get_pc(uc); 324 325 if (StubRoutines::is_safefetch_fault(pc)) { 326 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc)); 327 return 1; 328 } 329 330#ifndef AMD64 331 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs 332 // This can happen in any running code (currently more frequently in 333 // interpreter code but has been seen in compiled code) 334 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) { 335 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due " 336 "to unstable signal handling in this distribution."); 337 } 338#endif // AMD64 339 340 // Handle ALL stack overflow variations here 341 if (sig == SIGSEGV) { 342 address addr = (address) info->si_addr; 343 344 // check if fault address is within thread stack 345 if (thread->on_local_stack(addr)) { 346 // stack overflow 347 if (thread->in_stack_yellow_reserved_zone(addr)) { 348 if (thread->thread_state() == _thread_in_Java) { 349 if (thread->in_stack_reserved_zone(addr)) { 350 frame fr; 351 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) { 352 assert(fr.is_java_frame(), "Must be a Java frame"); 353 frame activation = 354 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr); 355 if (activation.sp() != NULL) { 356 thread->disable_stack_reserved_zone(); 357 if (activation.is_interpreted_frame()) { 358 thread->set_reserved_stack_activation((address)( 359 activation.fp() + frame::interpreter_frame_initial_sp_offset)); 360 } else { 361 thread->set_reserved_stack_activation((address)activation.unextended_sp()); 362 } 363 return 1; 364 } 365 } 366 } 367 // Throw a stack overflow exception. Guard pages will be reenabled 368 // while unwinding the stack. 369 thread->disable_stack_yellow_reserved_zone(); 370 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW); 371 } else { 372 // Thread was in the vm or native code. Return and try to finish. 373 thread->disable_stack_yellow_reserved_zone(); 374 return 1; 375 } 376 } else if (thread->in_stack_red_zone(addr)) { 377 // Fatal red zone violation. Disable the guard pages and fall through 378 // to handle_unexpected_exception way down below. 379 thread->disable_stack_red_zone(); 380 tty->print_raw_cr("An irrecoverable stack overflow has occurred."); 381 382 // This is a likely cause, but hard to verify. Let's just print 383 // it as a hint. 384 tty->print_raw_cr("Please check if any of your loaded .so files has " 385 "enabled executable stack (see man page execstack(8))"); 386 } else { 387 // Accessing stack address below sp may cause SEGV if current 388 // thread has MAP_GROWSDOWN stack. This should only happen when 389 // current thread was created by user code with MAP_GROWSDOWN flag 390 // and then attached to VM. See notes in os_linux.cpp. 391 if (thread->osthread()->expanding_stack() == 0) { 392 thread->osthread()->set_expanding_stack(); 393 if (os::Linux::manually_expand_stack(thread, addr)) { 394 thread->osthread()->clear_expanding_stack(); 395 return 1; 396 } 397 thread->osthread()->clear_expanding_stack(); 398 } else { 399 fatal("recursive segv. expanding stack."); 400 } 401 } 402 } 403 } 404 405 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) { 406 // Verify that OS save/restore AVX registers. 407 stub = VM_Version::cpuinfo_cont_addr(); 408 } 409 410 if (thread->thread_state() == _thread_in_Java) { 411 // Java thread running in Java code => find exception handler if any 412 // a fault inside compiled code, the interpreter, or a stub 413 414 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) { 415 stub = SharedRuntime::get_poll_stub(pc); 416 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) { 417 // BugId 4454115: A read from a MappedByteBuffer can fault 418 // here if the underlying file has been truncated. 419 // Do not crash the VM in such a case. 420 CodeBlob* cb = CodeCache::find_blob_unsafe(pc); 421 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL; 422 if (nm != NULL && nm->has_unsafe_access()) { 423 address next_pc = Assembler::locate_next_instruction(pc); 424 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 425 } 426 } 427 else 428 429#ifdef AMD64 430 if (sig == SIGFPE && 431 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) { 432 stub = 433 SharedRuntime:: 434 continuation_for_implicit_exception(thread, 435 pc, 436 SharedRuntime:: 437 IMPLICIT_DIVIDE_BY_ZERO); 438#else 439 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) { 440 // HACK: si_code does not work on linux 2.2.12-20!!! 441 int op = pc[0]; 442 if (op == 0xDB) { 443 // FIST 444 // TODO: The encoding of D2I in i486.ad can cause an exception 445 // prior to the fist instruction if there was an invalid operation 446 // pending. We want to dismiss that exception. From the win_32 447 // side it also seems that if it really was the fist causing 448 // the exception that we do the d2i by hand with different 449 // rounding. Seems kind of weird. 450 // NOTE: that we take the exception at the NEXT floating point instruction. 451 assert(pc[0] == 0xDB, "not a FIST opcode"); 452 assert(pc[1] == 0x14, "not a FIST opcode"); 453 assert(pc[2] == 0x24, "not a FIST opcode"); 454 return true; 455 } else if (op == 0xF7) { 456 // IDIV 457 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); 458 } else { 459 // TODO: handle more cases if we are using other x86 instructions 460 // that can generate SIGFPE signal on linux. 461 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op); 462 fatal("please update this code."); 463 } 464#endif // AMD64 465 } else if (sig == SIGSEGV && 466 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) { 467 // Determination of interpreter/vtable stub/compiled code null exception 468 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); 469 } 470 } else if (thread->thread_state() == _thread_in_vm && 471 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */ 472 thread->doing_unsafe_access()) { 473 address next_pc = Assembler::locate_next_instruction(pc); 474 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 475 } 476 477 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in 478 // and the heap gets shrunk before the field access. 479 if ((sig == SIGSEGV) || (sig == SIGBUS)) { 480 address addr = JNI_FastGetField::find_slowcase_pc(pc); 481 if (addr != (address)-1) { 482 stub = addr; 483 } 484 } 485 486 // Check to see if we caught the safepoint code in the 487 // process of write protecting the memory serialization page. 488 // It write enables the page immediately after protecting it 489 // so we can just return to retry the write. 490 if ((sig == SIGSEGV) && 491 os::is_memory_serialize_page(thread, (address) info->si_addr)) { 492 // Block current thread until the memory serialize page permission restored. 493 os::block_on_serialize_page_trap(); 494 return true; 495 } 496 } 497 498#ifndef AMD64 499 // Execution protection violation 500 // 501 // This should be kept as the last step in the triage. We don't 502 // have a dedicated trap number for a no-execute fault, so be 503 // conservative and allow other handlers the first shot. 504 // 505 // Note: We don't test that info->si_code == SEGV_ACCERR here. 506 // this si_code is so generic that it is almost meaningless; and 507 // the si_code for this condition may change in the future. 508 // Furthermore, a false-positive should be harmless. 509 if (UnguardOnExecutionViolation > 0 && 510 (sig == SIGSEGV || sig == SIGBUS) && 511 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) { 512 int page_size = os::vm_page_size(); 513 address addr = (address) info->si_addr; 514 address pc = os::Linux::ucontext_get_pc(uc); 515 // Make sure the pc and the faulting address are sane. 516 // 517 // If an instruction spans a page boundary, and the page containing 518 // the beginning of the instruction is executable but the following 519 // page is not, the pc and the faulting address might be slightly 520 // different - we still want to unguard the 2nd page in this case. 521 // 522 // 15 bytes seems to be a (very) safe value for max instruction size. 523 bool pc_is_near_addr = 524 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15); 525 bool instr_spans_page_boundary = 526 (align_size_down((intptr_t) pc ^ (intptr_t) addr, 527 (intptr_t) page_size) > 0); 528 529 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) { 530 static volatile address last_addr = 531 (address) os::non_memory_address_word(); 532 533 // In conservative mode, don't unguard unless the address is in the VM 534 if (addr != last_addr && 535 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) { 536 537 // Set memory to RWX and retry 538 address page_start = 539 (address) align_size_down((intptr_t) addr, (intptr_t) page_size); 540 bool res = os::protect_memory((char*) page_start, page_size, 541 os::MEM_PROT_RWX); 542 543 log_debug(os)("Execution protection violation " 544 "at " INTPTR_FORMAT 545 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr), 546 p2i(page_start), (res ? "success" : "failed"), errno); 547 stub = pc; 548 549 // Set last_addr so if we fault again at the same address, we don't end 550 // up in an endless loop. 551 // 552 // There are two potential complications here. Two threads trapping at 553 // the same address at the same time could cause one of the threads to 554 // think it already unguarded, and abort the VM. Likely very rare. 555 // 556 // The other race involves two threads alternately trapping at 557 // different addresses and failing to unguard the page, resulting in 558 // an endless loop. This condition is probably even more unlikely than 559 // the first. 560 // 561 // Although both cases could be avoided by using locks or thread local 562 // last_addr, these solutions are unnecessary complication: this 563 // handler is a best-effort safety net, not a complete solution. It is 564 // disabled by default and should only be used as a workaround in case 565 // we missed any no-execute-unsafe VM code. 566 567 last_addr = addr; 568 } 569 } 570 } 571#endif // !AMD64 572 573 if (stub != NULL) { 574 // save all thread context in case we need to restore it 575 if (thread != NULL) thread->set_saved_exception_pc(pc); 576 577 os::Linux::ucontext_set_pc(uc, stub); 578 return true; 579 } 580 581 // signal-chaining 582 if (os::Linux::chained_handler(sig, info, ucVoid)) { 583 return true; 584 } 585 586 if (!abort_if_unrecognized) { 587 // caller wants another chance, so give it to him 588 return false; 589 } 590 591 if (pc == NULL && uc != NULL) { 592 pc = os::Linux::ucontext_get_pc(uc); 593 } 594 595 // unmask current signal 596 sigset_t newset; 597 sigemptyset(&newset); 598 sigaddset(&newset, sig); 599 sigprocmask(SIG_UNBLOCK, &newset, NULL); 600 601 VMError::report_and_die(t, sig, pc, info, ucVoid); 602 603 ShouldNotReachHere(); 604 return true; // Mute compiler 605} 606 607void os::Linux::init_thread_fpu_state(void) { 608#ifndef AMD64 609 // set fpu to 53 bit precision 610 set_fpu_control_word(0x27f); 611#endif // !AMD64 612} 613 614int os::Linux::get_fpu_control_word(void) { 615#ifdef AMD64 616 return 0; 617#else 618 int fpu_control; 619 _FPU_GETCW(fpu_control); 620 return fpu_control & 0xffff; 621#endif // AMD64 622} 623 624void os::Linux::set_fpu_control_word(int fpu_control) { 625#ifndef AMD64 626 _FPU_SETCW(fpu_control); 627#endif // !AMD64 628} 629 630// Check that the linux kernel version is 2.4 or higher since earlier 631// versions do not support SSE without patches. 632bool os::supports_sse() { 633#ifdef AMD64 634 return true; 635#else 636 struct utsname uts; 637 if( uname(&uts) != 0 ) return false; // uname fails? 638 char *minor_string; 639 int major = strtol(uts.release,&minor_string,10); 640 int minor = strtol(minor_string+1,NULL,10); 641 bool result = (major > 2 || (major==2 && minor >= 4)); 642 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2", 643 major,minor, result ? "DOES" : "does NOT"); 644 return result; 645#endif // AMD64 646} 647 648bool os::is_allocatable(size_t bytes) { 649#ifdef AMD64 650 // unused on amd64? 651 return true; 652#else 653 654 if (bytes < 2 * G) { 655 return true; 656 } 657 658 char* addr = reserve_memory(bytes, NULL); 659 660 if (addr != NULL) { 661 release_memory(addr, bytes); 662 } 663 664 return addr != NULL; 665#endif // AMD64 666} 667 668//////////////////////////////////////////////////////////////////////////////// 669// thread stack 670 671#ifdef AMD64 672size_t os::Linux::min_stack_allowed = 64 * K; 673#else 674size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K; 675#endif // AMD64 676 677// return default stack size for thr_type 678size_t os::Linux::default_stack_size(os::ThreadType thr_type) { 679 // default stack size (compiler thread needs larger stack) 680#ifdef AMD64 681 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M); 682#else 683 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K); 684#endif // AMD64 685 return s; 686} 687 688size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 689 // Creating guard page is very expensive. Java thread has HotSpot 690 // guard page, only enable glibc guard page for non-Java threads. 691 return (thr_type == java_thread ? 0 : page_size()); 692} 693 694// Java thread: 695// 696// Low memory addresses 697// +------------------------+ 698// | |\ JavaThread created by VM does not have glibc 699// | glibc guard page | - guard, attached Java thread usually has 700// | |/ 1 page glibc guard. 701// P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 702// | |\ 703// | HotSpot Guard Pages | - red and yellow pages 704// | |/ 705// +------------------------+ JavaThread::stack_yellow_zone_base() 706// | |\ 707// | Normal Stack | - 708// | |/ 709// P2 +------------------------+ Thread::stack_base() 710// 711// Non-Java thread: 712// 713// Low memory addresses 714// +------------------------+ 715// | |\ 716// | glibc guard page | - usually 1 page 717// | |/ 718// P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 719// | |\ 720// | Normal Stack | - 721// | |/ 722// P2 +------------------------+ Thread::stack_base() 723// 724// ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from 725// pthread_attr_getstack() 726 727static void current_stack_region(address * bottom, size_t * size) { 728 if (os::Linux::is_initial_thread()) { 729 // initial thread needs special handling because pthread_getattr_np() 730 // may return bogus value. 731 *bottom = os::Linux::initial_thread_stack_bottom(); 732 *size = os::Linux::initial_thread_stack_size(); 733 } else { 734 pthread_attr_t attr; 735 736 int rslt = pthread_getattr_np(pthread_self(), &attr); 737 738 // JVM needs to know exact stack location, abort if it fails 739 if (rslt != 0) { 740 if (rslt == ENOMEM) { 741 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 742 } else { 743 fatal("pthread_getattr_np failed with errno = %d", rslt); 744 } 745 } 746 747 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 748 fatal("Can not locate current stack attributes!"); 749 } 750 751 pthread_attr_destroy(&attr); 752 753 } 754 assert(os::current_stack_pointer() >= *bottom && 755 os::current_stack_pointer() < *bottom + *size, "just checking"); 756} 757 758address os::current_stack_base() { 759 address bottom; 760 size_t size; 761 current_stack_region(&bottom, &size); 762 return (bottom + size); 763} 764 765size_t os::current_stack_size() { 766 // stack size includes normal stack and HotSpot guard pages 767 address bottom; 768 size_t size; 769 current_stack_region(&bottom, &size); 770 return size; 771} 772 773///////////////////////////////////////////////////////////////////////////// 774// helper functions for fatal error handler 775 776void os::print_context(outputStream *st, const void *context) { 777 if (context == NULL) return; 778 779 const ucontext_t *uc = (const ucontext_t*)context; 780 st->print_cr("Registers:"); 781#ifdef AMD64 782 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]); 783 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]); 784 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]); 785 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]); 786 st->cr(); 787 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]); 788 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]); 789 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]); 790 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]); 791 st->cr(); 792 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]); 793 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]); 794 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]); 795 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]); 796 st->cr(); 797 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]); 798 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]); 799 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]); 800 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]); 801 st->cr(); 802 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]); 803 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]); 804 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]); 805 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]); 806 st->cr(); 807 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]); 808#else 809 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]); 810 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]); 811 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]); 812 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]); 813 st->cr(); 814 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]); 815 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]); 816 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]); 817 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]); 818 st->cr(); 819 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]); 820 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]); 821 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2); 822#endif // AMD64 823 st->cr(); 824 st->cr(); 825 826 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc); 827 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp)); 828 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t)); 829 st->cr(); 830 831 // Note: it may be unsafe to inspect memory near pc. For example, pc may 832 // point to garbage if entry point in an nmethod is corrupted. Leave 833 // this at the end, and hope for the best. 834 address pc = os::Linux::ucontext_get_pc(uc); 835 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc)); 836 print_hex_dump(st, pc - 32, pc + 32, sizeof(char)); 837} 838 839void os::print_register_info(outputStream *st, const void *context) { 840 if (context == NULL) return; 841 842 const ucontext_t *uc = (const ucontext_t*)context; 843 844 st->print_cr("Register to memory mapping:"); 845 st->cr(); 846 847 // this is horrendously verbose but the layout of the registers in the 848 // context does not match how we defined our abstract Register set, so 849 // we can't just iterate through the gregs area 850 851 // this is only for the "general purpose" registers 852 853#ifdef AMD64 854 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]); 855 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]); 856 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]); 857 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]); 858 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]); 859 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]); 860 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]); 861 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]); 862 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]); 863 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]); 864 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]); 865 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]); 866 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]); 867 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]); 868 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]); 869 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]); 870#else 871 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]); 872 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]); 873 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]); 874 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]); 875 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]); 876 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]); 877 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]); 878 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]); 879#endif // AMD64 880 881 st->cr(); 882} 883 884void os::setup_fpu() { 885#ifndef AMD64 886 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std(); 887 __asm__ volatile ( "fldcw (%0)" : 888 : "r" (fpu_cntrl) : "memory"); 889#endif // !AMD64 890} 891 892#ifndef PRODUCT 893void os::verify_stack_alignment() { 894#ifdef AMD64 895 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment"); 896#endif 897} 898#endif 899 900 901/* 902 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit 903 * updates (JDK-8023956). 904 */ 905void os::workaround_expand_exec_shield_cs_limit() { 906#if defined(IA32) 907 size_t page_size = os::vm_page_size(); 908 /* 909 * Take the highest VA the OS will give us and exec 910 * 911 * Although using -(pagesz) as mmap hint works on newer kernel as you would 912 * think, older variants affected by this work-around don't (search forward only). 913 * 914 * On the affected distributions, we understand the memory layout to be: 915 * 916 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT. 917 * 918 * A few pages south main stack will do it. 919 * 920 * If we are embedded in an app other than launcher (initial != main stack), 921 * we don't have much control or understanding of the address space, just let it slide. 922 */ 923 char* hint = (char*)(Linux::initial_thread_stack_bottom() - 924 (JavaThread::stack_guard_zone_size() + page_size)); 925 char* codebuf = os::attempt_reserve_memory_at(page_size, hint); 926 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) { 927 return; // No matter, we tried, best effort. 928 } 929 930 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal); 931 932 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf); 933 934 // Some code to exec: the 'ret' instruction 935 codebuf[0] = 0xC3; 936 937 // Call the code in the codebuf 938 __asm__ volatile("call *%0" : : "r"(codebuf)); 939 940 // keep the page mapped so CS limit isn't reduced. 941#endif 942} 943 944int os::extra_bang_size_in_bytes() { 945 // JDK-8050147 requires the full cache line bang for x86. 946 return VM_Version::L1_line_size(); 947} 948