os_linux_x86.cpp revision 11658:8a5735c11a84
192108Sphk/* 292108Sphk * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved. 392108Sphk * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 492108Sphk * 592108Sphk * This code is free software; you can redistribute it and/or modify it 692108Sphk * under the terms of the GNU General Public License version 2 only, as 792108Sphk * published by the Free Software Foundation. 892108Sphk * 992108Sphk * This code is distributed in the hope that it will be useful, but WITHOUT 1092108Sphk * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1192108Sphk * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1292108Sphk * version 2 for more details (a copy is included in the LICENSE file that 1392108Sphk * accompanied this code). 1492108Sphk * 1592108Sphk * You should have received a copy of the GNU General Public License version 1692108Sphk * 2 along with this work; if not, write to the Free Software Foundation, 1792108Sphk * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 1892108Sphk * 1992108Sphk * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2092108Sphk * or visit www.oracle.com if you need additional information or have any 2192108Sphk * questions. 2292108Sphk * 2392108Sphk */ 2492108Sphk 2592108Sphk// no precompiled headers 2692108Sphk#include "asm/macroAssembler.hpp" 2792108Sphk#include "classfile/classLoader.hpp" 2892108Sphk#include "classfile/systemDictionary.hpp" 2992108Sphk#include "classfile/vmSymbols.hpp" 3092108Sphk#include "code/codeCache.hpp" 3192108Sphk#include "code/icBuffer.hpp" 3292108Sphk#include "code/vtableStubs.hpp" 3392108Sphk#include "interpreter/interpreter.hpp" 3492108Sphk#include "jvm_linux.h" 3592108Sphk#include "memory/allocation.inline.hpp" 3692108Sphk#include "os_share_linux.hpp" 3792108Sphk#include "prims/jniFastGetField.hpp" 3892108Sphk#include "prims/jvm.h" 3992108Sphk#include "prims/jvm_misc.hpp" 4092108Sphk#include "runtime/arguments.hpp" 4192108Sphk#include "runtime/extendedPC.hpp" 4292108Sphk#include "runtime/frame.inline.hpp" 4392108Sphk#include "runtime/interfaceSupport.hpp" 4492108Sphk#include "runtime/java.hpp" 4592108Sphk#include "runtime/javaCalls.hpp" 4692108Sphk#include "runtime/mutexLocker.hpp" 4792108Sphk#include "runtime/osThread.hpp" 4892108Sphk#include "runtime/sharedRuntime.hpp" 4992108Sphk#include "runtime/stubRoutines.hpp" 5092108Sphk#include "runtime/thread.inline.hpp" 5195323Sphk#include "runtime/timer.hpp" 5295038Sphk#include "services/memTracker.hpp" 5392108Sphk#include "utilities/events.hpp" 5492108Sphk#include "utilities/vmError.hpp" 5592108Sphk 5692108Sphk// put OS-includes here 5792108Sphk# include <sys/types.h> 5892108Sphk# include <sys/mman.h> 5992108Sphk# include <pthread.h> 6092108Sphk# include <signal.h> 6192108Sphk# include <errno.h> 6292108Sphk# include <dlfcn.h> 63104087Sphk# include <stdlib.h> 64104087Sphk# include <stdio.h> 65104087Sphk# include <unistd.h> 66104087Sphk# include <sys/resource.h> 67104087Sphk# include <pthread.h> 68104087Sphk# include <sys/stat.h> 69104087Sphk# include <sys/time.h> 70104087Sphk# include <sys/utsname.h> 71104087Sphk# include <sys/socket.h> 72104087Sphk# include <sys/wait.h> 73104087Sphk# include <pwd.h> 74104087Sphk# include <poll.h> 75104087Sphk# include <ucontext.h> 76104087Sphk# include <fpu_control.h> 7792108Sphk 7892108Sphk#ifdef AMD64 7992108Sphk#define REG_SP REG_RSP 8092108Sphk#define REG_PC REG_RIP 8192108Sphk#define REG_FP REG_RBP 8293248Sphk#define SPELL_REG_SP "rsp" 8397075Sphk#define SPELL_REG_FP "rbp" 8492108Sphk#else 8592108Sphk#define REG_SP REG_UESP 8698066Sphk#define REG_PC REG_EIP 8792108Sphk#define REG_FP REG_EBP 8892108Sphk#define SPELL_REG_SP "esp" 8992108Sphk#define SPELL_REG_FP "ebp" 90104087Sphk#endif // AMD64 9192108Sphk 9292108Sphkaddress os::current_stack_pointer() { 9392108Sphk#ifdef SPARC_WORKS 9492108Sphk register void *esp; 9592108Sphk __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp)); 9692108Sphk return (address) ((char*)esp + sizeof(long)*2); 9792108Sphk#elif defined(__clang__) 9898066Sphk intptr_t* esp; 9992108Sphk __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):); 10092108Sphk return (address) esp; 10192108Sphk#else 10293248Sphk register void *esp __asm__ (SPELL_REG_SP); 10392108Sphk return (address) esp; 10492108Sphk#endif 10592108Sphk} 10692108Sphk 10792108Sphkchar* os::non_memory_address_word() { 10892108Sphk // Must never look like an address returned by reserve_memory, 10992108Sphk // even in its subfields (as defined by the CPU immediate fields, 11092108Sphk // if the CPU splits constants across multiple instructions). 11192108Sphk 11292108Sphk return (char*) -1; 11392108Sphk} 11492108Sphk 11592108Sphkvoid os::initialize_thread(Thread* thr) { 11692108Sphk// Nothing to do. 11792108Sphk} 11896987Sphk 11992108Sphkaddress os::Linux::ucontext_get_pc(const ucontext_t * uc) { 12096987Sphk return (address)uc->uc_mcontext.gregs[REG_PC]; 12192108Sphk} 12292108Sphk 12392108Sphkvoid os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) { 12492108Sphk uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc; 12592108Sphk} 12692108Sphk 12792108Sphkintptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) { 12893250Sphk return (intptr_t*)uc->uc_mcontext.gregs[REG_SP]; 12992108Sphk} 13092108Sphk 13192108Sphkintptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) { 13292108Sphk return (intptr_t*)uc->uc_mcontext.gregs[REG_FP]; 13396987Sphk} 13492108Sphk 13592108Sphk// For Forte Analyzer AsyncGetCallTrace profiling support - thread 13692108Sphk// is currently interrupted by SIGPROF. 13792108Sphk// os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal 13892108Sphk// frames. Currently we don't do that on Linux, so it's the same as 13993248Sphk// os::fetch_frame_from_context(). 14092108Sphk// This method is also used for stack overflow signal handling. 14192108SphkExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread, 14293776Sphk const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) { 14392108Sphk 14496987Sphk assert(thread != NULL, "just checking"); 14596987Sphk assert(ret_sp != NULL, "just checking"); 14696987Sphk assert(ret_fp != NULL, "just checking"); 14796987Sphk 14896987Sphk return os::fetch_frame_from_context(uc, ret_sp, ret_fp); 14996987Sphk} 15096987Sphk 15192108SphkExtendedPC os::fetch_frame_from_context(const void* ucVoid, 15292108Sphk intptr_t** ret_sp, intptr_t** ret_fp) { 15396987Sphk 154104316Sphk ExtendedPC epc; 15596987Sphk const ucontext_t* uc = (const ucontext_t*)ucVoid; 15696987Sphk 15796987Sphk if (uc != NULL) { 15892108Sphk epc = ExtendedPC(os::Linux::ucontext_get_pc(uc)); 15992108Sphk if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc); 16092108Sphk if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc); 16192108Sphk } else { 16292108Sphk // construct empty ExtendedPC for return value checking 16392108Sphk epc = ExtendedPC(NULL); 16492108Sphk if (ret_sp) *ret_sp = (intptr_t *)NULL; 16592108Sphk if (ret_fp) *ret_fp = (intptr_t *)NULL; 16692108Sphk } 16792108Sphk 16892108Sphk return epc; 16992108Sphk} 17092108Sphk 17192108Sphkframe os::fetch_frame_from_context(const void* ucVoid) { 17292108Sphk intptr_t* sp; 17392108Sphk intptr_t* fp; 17492108Sphk ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp); 17592108Sphk return frame(sp, fp, epc.pc()); 17692108Sphk} 17792479Sphk 17892108Sphkframe os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) { 17992108Sphk intptr_t* sp; 18092108Sphk intptr_t* fp; 18192108Sphk ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp); 182103004Sphk return frame(sp, fp, epc.pc()); 18392108Sphk} 184103004Sphk 185103004Sphkbool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) { 186103004Sphk address pc = (address) os::Linux::ucontext_get_pc(uc); 18792108Sphk if (Interpreter::contains(pc)) { 18892108Sphk // interpreter performs stack banging after the fixed frame header has 18992479Sphk // been generated while the compilers perform it before. To maintain 19098066Sphk // semantic consistency between interpreted and compiled frames, the 19192108Sphk // method returns the Java sender of the current frame. 19292108Sphk *fr = os::fetch_frame_from_ucontext(thread, uc); 19392108Sphk if (!fr->is_first_java_frame()) { 19492108Sphk assert(fr->safe_for_sender(thread), "Safety check"); 19592108Sphk *fr = fr->java_sender(); 19692108Sphk } 19792108Sphk } else { 19892108Sphk // more complex code with compiled code 19992108Sphk assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above"); 20092108Sphk CodeBlob* cb = CodeCache::find_blob(pc); 20192108Sphk if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) { 20292108Sphk // Not sure where the pc points to, fallback to default 20392108Sphk // stack overflow handling 20492108Sphk return false; 20592108Sphk } else { 20692108Sphk // in compiled code, the stack banging is performed just after the return pc 20792479Sphk // has been pushed on the stack 20892108Sphk intptr_t* fp = os::Linux::ucontext_get_fp(uc); 20992108Sphk intptr_t* sp = os::Linux::ucontext_get_sp(uc); 21092108Sphk *fr = frame(sp + 1, fp, (address)*sp); 21192108Sphk if (!fr->is_java_frame()) { 212103004Sphk assert(fr->safe_for_sender(thread), "Safety check"); 21392108Sphk assert(!fr->is_first_frame(), "Safety check"); 214103004Sphk *fr = fr->java_sender(); 215103004Sphk } 216103004Sphk } 21792108Sphk } 21892108Sphk assert(fr->is_java_frame(), "Safety check"); 21992479Sphk return true; 22098066Sphk} 22192108Sphk 22292108Sphk// By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get 22392108Sphk// turned off by -fomit-frame-pointer, 22492108Sphkframe os::get_sender_for_C_frame(frame* fr) { 22592108Sphk return frame(fr->sender_sp(), fr->link(), fr->sender_pc()); 22692108Sphk} 22795323Sphk 22892108Sphkintptr_t* _get_previous_fp() { 22995323Sphk#ifdef SPARC_WORKS 23095038Sphk register intptr_t **ebp; 23192108Sphk __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp)); 23295038Sphk#elif defined(__clang__) 23392403Sphk intptr_t **ebp; 23492108Sphk __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):); 23592108Sphk#else 23692108Sphk register intptr_t **ebp __asm__ (SPELL_REG_FP); 23795323Sphk#endif 23895323Sphk return (intptr_t*) *ebp; // we want what it points to. 239104602Sphk} 24092108Sphk 24192108Sphk 24292479Sphkframe os::current_frame() { 24392403Sphk intptr_t* fp = _get_previous_fp(); 24492698Sphk frame myframe((intptr_t*)os::current_stack_pointer(), 24592698Sphk (intptr_t*)fp, 24692698Sphk CAST_FROM_FN_PTR(address, os::current_frame)); 24793250Sphk if (os::is_first_C_frame(&myframe)) { 248105180Snjl // stack is not walkable 249105180Snjl return frame(); 25092698Sphk } else { 25192698Sphk return os::get_sender_for_C_frame(&myframe); 25293250Sphk } 253105180Snjl} 254105180Snjl 25592698Sphk// Utility functions 25692698Sphk 25793250Sphk// From IA32 System Programming Guide 258105180Snjlenum { 259105180Snjl trap_page_fault = 0xE 26092698Sphk}; 26192698Sphk 26293250Sphkextern "C" JNIEXPORT int 263105180SnjlJVM_handle_linux_signal(int sig, 264105180Snjl siginfo_t* info, 26592698Sphk void* ucVoid, 26694287Sphk int abort_if_unrecognized) { 26794287Sphk ucontext_t* uc = (ucontext_t*) ucVoid; 26894287Sphk 26995038Sphk Thread* t = Thread::current_or_null_safe(); 27095038Sphk 27195038Sphk // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away 27295038Sphk // (no destructors can be run) 27395038Sphk os::WatcherThreadCrashProtection::check_crash_protection(sig, t); 27495038Sphk 27595038Sphk SignalHandlerMark shm(t); 27695038Sphk 27795038Sphk // Note: it's not uncommon that JNI code uses signal/sigset to install 27895038Sphk // then restore certain signal handler (e.g. to temporarily block SIGPIPE, 27995038Sphk // or have a SIGILL handler when detecting CPU type). When that happens, 28095038Sphk // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To 28195038Sphk // avoid unnecessary crash when libjsig is not preloaded, try handle signals 28295038Sphk // that do not require siginfo/ucontext first. 283104602Sphk 28492698Sphk if (sig == SIGPIPE || sig == SIGXFSZ) { 285104602Sphk // allow chained handler to go first 28692698Sphk if (os::Linux::chained_handler(sig, info, ucVoid)) { 28792698Sphk return true; 28892698Sphk } else { 28992698Sphk // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219 29092698Sphk return true; 29192698Sphk } 29293250Sphk } 29392698Sphk 29493250Sphk JavaThread* thread = NULL; 29592698Sphk VMThread* vmthread = NULL; 29692698Sphk if (os::Linux::signal_handlers_are_installed) { 29792403Sphk if (t != NULL ){ 29892479Sphk if(t->is_Java_thread()) { 299104602Sphk thread = (JavaThread*)t; 300104602Sphk } 301104602Sphk else if(t->is_VM_thread()){ 302104602Sphk vmthread = (VMThread *)t; 303104602Sphk } 304104602Sphk } 305104602Sphk } 30698066Sphk/* 30792403Sphk NOTE: does not seem to work on linux. 308104357Sphk if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) { 309104357Sphk // can't decode this kind of signal 310104357Sphk info = NULL; 311104357Sphk } else { 312104357Sphk assert(sig == info->si_signo, "bad siginfo"); 313104357Sphk } 314104357Sphk*/ 315104357Sphk // decide if this trap can be handled by a stub 316104357Sphk address stub = NULL; 317104357Sphk 318104357Sphk address pc = NULL; 319104357Sphk 320104357Sphk //%note os_trap_1 321104357Sphk if (info != NULL && uc != NULL && thread != NULL) { 32292403Sphk pc = (address) os::Linux::ucontext_get_pc(uc); 32392108Sphk 32492108Sphk if (StubRoutines::is_safefetch_fault(pc)) { 32592108Sphk os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc)); 32692108Sphk return 1; 32792108Sphk } 32892108Sphk 32992108Sphk#ifndef AMD64 33092108Sphk // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs 33192108Sphk // This can happen in any running code (currently more frequently in 33292108Sphk // interpreter code but has been seen in compiled code) 33392108Sphk if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) { 33492108Sphk fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due " 33592108Sphk "to unstable signal handling in this distribution."); 33692108Sphk } 33793250Sphk#endif // AMD64 33892108Sphk 33992108Sphk // Handle ALL stack overflow variations here 34092108Sphk if (sig == SIGSEGV) { 34192108Sphk address addr = (address) info->si_addr; 34292108Sphk 34392108Sphk // check if fault address is within thread stack 34492108Sphk if (thread->on_local_stack(addr)) { 34592108Sphk // stack overflow 34692108Sphk if (thread->in_stack_yellow_reserved_zone(addr)) { 34792108Sphk if (thread->thread_state() == _thread_in_Java) { 34892108Sphk if (thread->in_stack_reserved_zone(addr)) { 34992108Sphk frame fr; 35092108Sphk if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) { 35192108Sphk assert(fr.is_java_frame(), "Must be a Java frame"); 35292108Sphk frame activation = 35392108Sphk SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr); 35492108Sphk if (activation.sp() != NULL) { 35592108Sphk thread->disable_stack_reserved_zone(); 35692108Sphk if (activation.is_interpreted_frame()) { 35792108Sphk thread->set_reserved_stack_activation((address)( 35892108Sphk activation.fp() + frame::interpreter_frame_initial_sp_offset)); 35992108Sphk } else { 36092108Sphk thread->set_reserved_stack_activation((address)activation.unextended_sp()); 36192108Sphk } 36292108Sphk return 1; 36392108Sphk } 36492108Sphk } 36592108Sphk } 36692108Sphk // Throw a stack overflow exception. Guard pages will be reenabled 36792108Sphk // while unwinding the stack. 36892108Sphk thread->disable_stack_yellow_reserved_zone(); 36992108Sphk stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW); 37092108Sphk } else { 37192108Sphk // Thread was in the vm or native code. Return and try to finish. 37292108Sphk thread->disable_stack_yellow_reserved_zone(); 37392108Sphk return 1; 37492108Sphk } 37592108Sphk } else if (thread->in_stack_red_zone(addr)) { 37692108Sphk // Fatal red zone violation. Disable the guard pages and fall through 37792108Sphk // to handle_unexpected_exception way down below. 37892108Sphk thread->disable_stack_red_zone(); 37992108Sphk tty->print_raw_cr("An irrecoverable stack overflow has occurred."); 38092108Sphk 38192108Sphk // This is a likely cause, but hard to verify. Let's just print 38292108Sphk // it as a hint. 38392108Sphk tty->print_raw_cr("Please check if any of your loaded .so files has " 38492108Sphk "enabled executable stack (see man page execstack(8))"); 38592108Sphk } else { 38692108Sphk // Accessing stack address below sp may cause SEGV if current 38796987Sphk // thread has MAP_GROWSDOWN stack. This should only happen when 38896987Sphk // current thread was created by user code with MAP_GROWSDOWN flag 38996987Sphk // and then attached to VM. See notes in os_linux.cpp. 39096987Sphk if (thread->osthread()->expanding_stack() == 0) { 39196987Sphk thread->osthread()->set_expanding_stack(); 39296987Sphk if (os::Linux::manually_expand_stack(thread, addr)) { 39396987Sphk thread->osthread()->clear_expanding_stack(); 39496987Sphk return 1; 39596987Sphk } 39696987Sphk thread->osthread()->clear_expanding_stack(); 39792108Sphk } else { 39892108Sphk fatal("recursive segv. expanding stack."); 39993250Sphk } 40092108Sphk } 40192108Sphk } 40292108Sphk } 40392108Sphk 40492108Sphk if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) { 40592108Sphk // Verify that OS save/restore AVX registers. 40692108Sphk stub = VM_Version::cpuinfo_cont_addr(); 40792108Sphk } 40892108Sphk 40992108Sphk if (thread->thread_state() == _thread_in_Java) { 41095038Sphk // Java thread running in Java code => find exception handler if any 41195038Sphk // a fault inside compiled code, the interpreter, or a stub 41296987Sphk 41392108Sphk if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) { 41492108Sphk stub = SharedRuntime::get_poll_stub(pc); 41592108Sphk } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) { 41698066Sphk // BugId 4454115: A read from a MappedByteBuffer can fault 41792108Sphk // here if the underlying file has been truncated. 41892108Sphk // Do not crash the VM in such a case. 41992108Sphk CodeBlob* cb = CodeCache::find_blob_unsafe(pc); 42092108Sphk CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL; 42196987Sphk if (nm != NULL && nm->has_unsafe_access()) { 422 address next_pc = Assembler::locate_next_instruction(pc); 423 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 424 } 425 } 426 else 427 428#ifdef AMD64 429 if (sig == SIGFPE && 430 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) { 431 stub = 432 SharedRuntime:: 433 continuation_for_implicit_exception(thread, 434 pc, 435 SharedRuntime:: 436 IMPLICIT_DIVIDE_BY_ZERO); 437#else 438 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) { 439 // HACK: si_code does not work on linux 2.2.12-20!!! 440 int op = pc[0]; 441 if (op == 0xDB) { 442 // FIST 443 // TODO: The encoding of D2I in i486.ad can cause an exception 444 // prior to the fist instruction if there was an invalid operation 445 // pending. We want to dismiss that exception. From the win_32 446 // side it also seems that if it really was the fist causing 447 // the exception that we do the d2i by hand with different 448 // rounding. Seems kind of weird. 449 // NOTE: that we take the exception at the NEXT floating point instruction. 450 assert(pc[0] == 0xDB, "not a FIST opcode"); 451 assert(pc[1] == 0x14, "not a FIST opcode"); 452 assert(pc[2] == 0x24, "not a FIST opcode"); 453 return true; 454 } else if (op == 0xF7) { 455 // IDIV 456 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); 457 } else { 458 // TODO: handle more cases if we are using other x86 instructions 459 // that can generate SIGFPE signal on linux. 460 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op); 461 fatal("please update this code."); 462 } 463#endif // AMD64 464 } else if (sig == SIGSEGV && 465 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) { 466 // Determination of interpreter/vtable stub/compiled code null exception 467 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); 468 } 469 } else if (thread->thread_state() == _thread_in_vm && 470 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */ 471 thread->doing_unsafe_access()) { 472 address next_pc = Assembler::locate_next_instruction(pc); 473 stub = SharedRuntime::handle_unsafe_access(thread, next_pc); 474 } 475 476 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in 477 // and the heap gets shrunk before the field access. 478 if ((sig == SIGSEGV) || (sig == SIGBUS)) { 479 address addr = JNI_FastGetField::find_slowcase_pc(pc); 480 if (addr != (address)-1) { 481 stub = addr; 482 } 483 } 484 485 // Check to see if we caught the safepoint code in the 486 // process of write protecting the memory serialization page. 487 // It write enables the page immediately after protecting it 488 // so we can just return to retry the write. 489 if ((sig == SIGSEGV) && 490 os::is_memory_serialize_page(thread, (address) info->si_addr)) { 491 // Block current thread until the memory serialize page permission restored. 492 os::block_on_serialize_page_trap(); 493 return true; 494 } 495 } 496 497#ifndef AMD64 498 // Execution protection violation 499 // 500 // This should be kept as the last step in the triage. We don't 501 // have a dedicated trap number for a no-execute fault, so be 502 // conservative and allow other handlers the first shot. 503 // 504 // Note: We don't test that info->si_code == SEGV_ACCERR here. 505 // this si_code is so generic that it is almost meaningless; and 506 // the si_code for this condition may change in the future. 507 // Furthermore, a false-positive should be harmless. 508 if (UnguardOnExecutionViolation > 0 && 509 (sig == SIGSEGV || sig == SIGBUS) && 510 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) { 511 int page_size = os::vm_page_size(); 512 address addr = (address) info->si_addr; 513 address pc = os::Linux::ucontext_get_pc(uc); 514 // Make sure the pc and the faulting address are sane. 515 // 516 // If an instruction spans a page boundary, and the page containing 517 // the beginning of the instruction is executable but the following 518 // page is not, the pc and the faulting address might be slightly 519 // different - we still want to unguard the 2nd page in this case. 520 // 521 // 15 bytes seems to be a (very) safe value for max instruction size. 522 bool pc_is_near_addr = 523 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15); 524 bool instr_spans_page_boundary = 525 (align_size_down((intptr_t) pc ^ (intptr_t) addr, 526 (intptr_t) page_size) > 0); 527 528 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) { 529 static volatile address last_addr = 530 (address) os::non_memory_address_word(); 531 532 // In conservative mode, don't unguard unless the address is in the VM 533 if (addr != last_addr && 534 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) { 535 536 // Set memory to RWX and retry 537 address page_start = 538 (address) align_size_down((intptr_t) addr, (intptr_t) page_size); 539 bool res = os::protect_memory((char*) page_start, page_size, 540 os::MEM_PROT_RWX); 541 542 log_debug(os)("Execution protection violation " 543 "at " INTPTR_FORMAT 544 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr), 545 p2i(page_start), (res ? "success" : "failed"), errno); 546 stub = pc; 547 548 // Set last_addr so if we fault again at the same address, we don't end 549 // up in an endless loop. 550 // 551 // There are two potential complications here. Two threads trapping at 552 // the same address at the same time could cause one of the threads to 553 // think it already unguarded, and abort the VM. Likely very rare. 554 // 555 // The other race involves two threads alternately trapping at 556 // different addresses and failing to unguard the page, resulting in 557 // an endless loop. This condition is probably even more unlikely than 558 // the first. 559 // 560 // Although both cases could be avoided by using locks or thread local 561 // last_addr, these solutions are unnecessary complication: this 562 // handler is a best-effort safety net, not a complete solution. It is 563 // disabled by default and should only be used as a workaround in case 564 // we missed any no-execute-unsafe VM code. 565 566 last_addr = addr; 567 } 568 } 569 } 570#endif // !AMD64 571 572 if (stub != NULL) { 573 // save all thread context in case we need to restore it 574 if (thread != NULL) thread->set_saved_exception_pc(pc); 575 576 os::Linux::ucontext_set_pc(uc, stub); 577 return true; 578 } 579 580 // signal-chaining 581 if (os::Linux::chained_handler(sig, info, ucVoid)) { 582 return true; 583 } 584 585 if (!abort_if_unrecognized) { 586 // caller wants another chance, so give it to him 587 return false; 588 } 589 590 if (pc == NULL && uc != NULL) { 591 pc = os::Linux::ucontext_get_pc(uc); 592 } 593 594 // unmask current signal 595 sigset_t newset; 596 sigemptyset(&newset); 597 sigaddset(&newset, sig); 598 sigprocmask(SIG_UNBLOCK, &newset, NULL); 599 600 VMError::report_and_die(t, sig, pc, info, ucVoid); 601 602 ShouldNotReachHere(); 603 return true; // Mute compiler 604} 605 606void os::Linux::init_thread_fpu_state(void) { 607#ifndef AMD64 608 // set fpu to 53 bit precision 609 set_fpu_control_word(0x27f); 610#endif // !AMD64 611} 612 613int os::Linux::get_fpu_control_word(void) { 614#ifdef AMD64 615 return 0; 616#else 617 int fpu_control; 618 _FPU_GETCW(fpu_control); 619 return fpu_control & 0xffff; 620#endif // AMD64 621} 622 623void os::Linux::set_fpu_control_word(int fpu_control) { 624#ifndef AMD64 625 _FPU_SETCW(fpu_control); 626#endif // !AMD64 627} 628 629// Check that the linux kernel version is 2.4 or higher since earlier 630// versions do not support SSE without patches. 631bool os::supports_sse() { 632#ifdef AMD64 633 return true; 634#else 635 struct utsname uts; 636 if( uname(&uts) != 0 ) return false; // uname fails? 637 char *minor_string; 638 int major = strtol(uts.release,&minor_string,10); 639 int minor = strtol(minor_string+1,NULL,10); 640 bool result = (major > 2 || (major==2 && minor >= 4)); 641 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2", 642 major,minor, result ? "DOES" : "does NOT"); 643 return result; 644#endif // AMD64 645} 646 647bool os::is_allocatable(size_t bytes) { 648#ifdef AMD64 649 // unused on amd64? 650 return true; 651#else 652 653 if (bytes < 2 * G) { 654 return true; 655 } 656 657 char* addr = reserve_memory(bytes, NULL); 658 659 if (addr != NULL) { 660 release_memory(addr, bytes); 661 } 662 663 return addr != NULL; 664#endif // AMD64 665} 666 667//////////////////////////////////////////////////////////////////////////////// 668// thread stack 669 670#ifdef AMD64 671size_t os::Linux::min_stack_allowed = 64 * K; 672#else 673size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K; 674#endif // AMD64 675 676// return default stack size for thr_type 677size_t os::Linux::default_stack_size(os::ThreadType thr_type) { 678 // default stack size (compiler thread needs larger stack) 679#ifdef AMD64 680 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M); 681#else 682 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K); 683#endif // AMD64 684 return s; 685} 686 687size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 688 // Creating guard page is very expensive. Java thread has HotSpot 689 // guard page, only enable glibc guard page for non-Java threads. 690 return (thr_type == java_thread ? 0 : page_size()); 691} 692 693// Java thread: 694// 695// Low memory addresses 696// +------------------------+ 697// | |\ JavaThread created by VM does not have glibc 698// | glibc guard page | - guard, attached Java thread usually has 699// | |/ 1 page glibc guard. 700// P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 701// | |\ 702// | HotSpot Guard Pages | - red and yellow pages 703// | |/ 704// +------------------------+ JavaThread::stack_yellow_zone_base() 705// | |\ 706// | Normal Stack | - 707// | |/ 708// P2 +------------------------+ Thread::stack_base() 709// 710// Non-Java thread: 711// 712// Low memory addresses 713// +------------------------+ 714// | |\ 715// | glibc guard page | - usually 1 page 716// | |/ 717// P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 718// | |\ 719// | Normal Stack | - 720// | |/ 721// P2 +------------------------+ Thread::stack_base() 722// 723// ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from 724// pthread_attr_getstack() 725 726static void current_stack_region(address * bottom, size_t * size) { 727 if (os::Linux::is_initial_thread()) { 728 // initial thread needs special handling because pthread_getattr_np() 729 // may return bogus value. 730 *bottom = os::Linux::initial_thread_stack_bottom(); 731 *size = os::Linux::initial_thread_stack_size(); 732 } else { 733 pthread_attr_t attr; 734 735 int rslt = pthread_getattr_np(pthread_self(), &attr); 736 737 // JVM needs to know exact stack location, abort if it fails 738 if (rslt != 0) { 739 if (rslt == ENOMEM) { 740 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 741 } else { 742 fatal("pthread_getattr_np failed with errno = %d", rslt); 743 } 744 } 745 746 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 747 fatal("Can not locate current stack attributes!"); 748 } 749 750 pthread_attr_destroy(&attr); 751 752 } 753 assert(os::current_stack_pointer() >= *bottom && 754 os::current_stack_pointer() < *bottom + *size, "just checking"); 755} 756 757address os::current_stack_base() { 758 address bottom; 759 size_t size; 760 current_stack_region(&bottom, &size); 761 return (bottom + size); 762} 763 764size_t os::current_stack_size() { 765 // stack size includes normal stack and HotSpot guard pages 766 address bottom; 767 size_t size; 768 current_stack_region(&bottom, &size); 769 return size; 770} 771 772///////////////////////////////////////////////////////////////////////////// 773// helper functions for fatal error handler 774 775void os::print_context(outputStream *st, const void *context) { 776 if (context == NULL) return; 777 778 const ucontext_t *uc = (const ucontext_t*)context; 779 st->print_cr("Registers:"); 780#ifdef AMD64 781 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]); 782 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]); 783 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]); 784 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]); 785 st->cr(); 786 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]); 787 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]); 788 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]); 789 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]); 790 st->cr(); 791 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]); 792 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]); 793 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]); 794 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]); 795 st->cr(); 796 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]); 797 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]); 798 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]); 799 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]); 800 st->cr(); 801 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]); 802 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]); 803 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]); 804 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]); 805 st->cr(); 806 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]); 807#else 808 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]); 809 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]); 810 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]); 811 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]); 812 st->cr(); 813 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]); 814 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]); 815 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]); 816 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]); 817 st->cr(); 818 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]); 819 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]); 820 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2); 821#endif // AMD64 822 st->cr(); 823 st->cr(); 824 825 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc); 826 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp)); 827 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t)); 828 st->cr(); 829 830 // Note: it may be unsafe to inspect memory near pc. For example, pc may 831 // point to garbage if entry point in an nmethod is corrupted. Leave 832 // this at the end, and hope for the best. 833 address pc = os::Linux::ucontext_get_pc(uc); 834 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc)); 835 print_hex_dump(st, pc - 32, pc + 32, sizeof(char)); 836} 837 838void os::print_register_info(outputStream *st, const void *context) { 839 if (context == NULL) return; 840 841 const ucontext_t *uc = (const ucontext_t*)context; 842 843 st->print_cr("Register to memory mapping:"); 844 st->cr(); 845 846 // this is horrendously verbose but the layout of the registers in the 847 // context does not match how we defined our abstract Register set, so 848 // we can't just iterate through the gregs area 849 850 // this is only for the "general purpose" registers 851 852#ifdef AMD64 853 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]); 854 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]); 855 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]); 856 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]); 857 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]); 858 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]); 859 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]); 860 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]); 861 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]); 862 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]); 863 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]); 864 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]); 865 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]); 866 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]); 867 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]); 868 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]); 869#else 870 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]); 871 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]); 872 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]); 873 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]); 874 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]); 875 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]); 876 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]); 877 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]); 878#endif // AMD64 879 880 st->cr(); 881} 882 883void os::setup_fpu() { 884#ifndef AMD64 885 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std(); 886 __asm__ volatile ( "fldcw (%0)" : 887 : "r" (fpu_cntrl) : "memory"); 888#endif // !AMD64 889} 890 891#ifndef PRODUCT 892void os::verify_stack_alignment() { 893#ifdef AMD64 894 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment"); 895#endif 896} 897#endif 898 899 900/* 901 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit 902 * updates (JDK-8023956). 903 */ 904void os::workaround_expand_exec_shield_cs_limit() { 905#if defined(IA32) 906 size_t page_size = os::vm_page_size(); 907 /* 908 * Take the highest VA the OS will give us and exec 909 * 910 * Although using -(pagesz) as mmap hint works on newer kernel as you would 911 * think, older variants affected by this work-around don't (search forward only). 912 * 913 * On the affected distributions, we understand the memory layout to be: 914 * 915 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT. 916 * 917 * A few pages south main stack will do it. 918 * 919 * If we are embedded in an app other than launcher (initial != main stack), 920 * we don't have much control or understanding of the address space, just let it slide. 921 */ 922 char* hint = (char*)(Linux::initial_thread_stack_bottom() - 923 (JavaThread::stack_guard_zone_size() + page_size)); 924 char* codebuf = os::attempt_reserve_memory_at(page_size, hint); 925 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) { 926 return; // No matter, we tried, best effort. 927 } 928 929 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal); 930 931 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf); 932 933 // Some code to exec: the 'ret' instruction 934 codebuf[0] = 0xC3; 935 936 // Call the code in the codebuf 937 __asm__ volatile("call *%0" : : "r"(codebuf)); 938 939 // keep the page mapped so CS limit isn't reduced. 940#endif 941} 942 943int os::extra_bang_size_in_bytes() { 944 // JDK-8050147 requires the full cache line bang for x86. 945 return VM_Version::L1_line_size(); 946} 947