/* * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2016, 2018 SAP SE. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ // This file is organized as os_linux_x86.cpp. // no precompiled headers #include "jvm.h" #include "asm/assembler.inline.hpp" #include "classfile/classLoader.hpp" #include "classfile/systemDictionary.hpp" #include "classfile/vmSymbols.hpp" #include "code/icBuffer.hpp" #include "code/nativeInst.hpp" #include "code/vtableStubs.hpp" #include "compiler/disassembler.hpp" #include "interpreter/interpreter.hpp" #include "memory/allocation.inline.hpp" #include "nativeInst_s390.hpp" #include "os_share_linux.hpp" #include "prims/jniFastGetField.hpp" #include "prims/jvm_misc.hpp" #include "runtime/arguments.hpp" #include "runtime/extendedPC.hpp" #include "runtime/frame.inline.hpp" #include "runtime/interfaceSupport.inline.hpp" #include "runtime/java.hpp" #include "runtime/javaCalls.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/osThread.hpp" #include "runtime/sharedRuntime.hpp" #include "runtime/stubRoutines.hpp" #include "runtime/thread.inline.hpp" #include "runtime/timer.hpp" #include "utilities/events.hpp" #include "utilities/debug.hpp" #include "utilities/vmError.hpp" // put OS-includes here # include # include # include # include # include # include # include # include # include # include # include # include # include # include # include # include # include # include # include address os::current_stack_pointer() { intptr_t* csp; // Inline assembly for `z_lgr regno(csp), Z_SP' (Z_SP = Z_R15): __asm__ __volatile__ ("lgr %0, 15":"=r"(csp):); assert(((uint64_t)csp & (frame::alignment_in_bytes-1)) == 0, "SP must be aligned"); return (address) csp; } char* os::non_memory_address_word() { // Must never look like an address returned by reserve_memory, // even in its subfields (as defined by the CPU immediate fields, // if the CPU splits constants across multiple instructions). return (char*) -1; } // Frame information (pc, sp, fp) retrieved via ucontext // always looks like a C-frame according to the frame // conventions in frame_s390.hpp. address os::Linux::ucontext_get_pc(const ucontext_t * uc) { return (address)uc->uc_mcontext.psw.addr; } void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) { uc->uc_mcontext.psw.addr = (unsigned long)pc; } static address ucontext_get_lr(const ucontext_t * uc) { return (address)uc->uc_mcontext.gregs[14/*LINK*/]; } intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) { return (intptr_t*)uc->uc_mcontext.gregs[15/*REG_SP*/]; } intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) { return NULL; } ExtendedPC os::fetch_frame_from_context(const void* ucVoid, intptr_t** ret_sp, intptr_t** ret_fp) { ExtendedPC epc; const ucontext_t* uc = (const ucontext_t*)ucVoid; if (uc != NULL) { epc = ExtendedPC(os::Linux::ucontext_get_pc(uc)); if (ret_sp) { *ret_sp = os::Linux::ucontext_get_sp(uc); } if (ret_fp) { *ret_fp = os::Linux::ucontext_get_fp(uc); } } else { // Construct empty ExtendedPC for return value checking. epc = ExtendedPC(NULL); if (ret_sp) { *ret_sp = (intptr_t *)NULL; } if (ret_fp) { *ret_fp = (intptr_t *)NULL; } } return epc; } frame os::fetch_frame_from_context(const void* ucVoid) { intptr_t* sp; intptr_t* fp; ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp); return frame(sp, epc.pc()); } bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) { address pc = (address) os::Linux::ucontext_get_pc(uc); if (Interpreter::contains(pc)) { // Interpreter performs stack banging after the fixed frame header has // been generated while the compilers perform it before. To maintain // semantic consistency between interpreted and compiled frames, the // method returns the Java sender of the current frame. *fr = os::fetch_frame_from_context(uc); if (!fr->is_first_java_frame()) { assert(fr->safe_for_sender(thread), "Safety check"); *fr = fr->java_sender(); } } else { // More complex code with compiled code. assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above"); CodeBlob* cb = CodeCache::find_blob(pc); if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) { // Not sure where the pc points to, fallback to default // stack overflow handling. In compiled code, we bang before // the frame is complete. return false; } else { intptr_t* sp = os::Linux::ucontext_get_sp(uc); address lr = ucontext_get_lr(uc); *fr = frame(sp, lr); if (!fr->is_java_frame()) { assert(fr->safe_for_sender(thread), "Safety check"); assert(!fr->is_first_frame(), "Safety check"); *fr = fr->java_sender(); } } } assert(fr->is_java_frame(), "Safety check"); return true; } frame os::get_sender_for_C_frame(frame* fr) { if (*fr->sp() == 0) { // fr is the last C frame. return frame(); } // If its not one of our frames, the return pc is saved at gpr14 // stack slot. The call_stub stores the return_pc to the stack slot // of gpr10. if ((Interpreter::code() != NULL && Interpreter::contains(fr->pc())) || (CodeCache::contains(fr->pc()) && !StubRoutines::contains(fr->pc()))) { return frame(fr->sender_sp(), fr->sender_pc()); } else { if (StubRoutines::contains(fr->pc())) { StubCodeDesc* desc = StubCodeDesc::desc_for(fr->pc()); if (desc && !strcmp(desc->name(),"call_stub")) { return frame(fr->sender_sp(), fr->callstub_sender_pc()); } else { return frame(fr->sender_sp(), fr->sender_pc()); } } else { return frame(fr->sender_sp(), fr->native_sender_pc()); } } } frame os::current_frame() { // Expected to return the stack pointer of this method. // But if inlined, returns the stack pointer of our caller! intptr_t* csp = (intptr_t*) *((intptr_t*) os::current_stack_pointer()); assert (csp != NULL, "sp should not be NULL"); // Pass a dummy pc. This way we don't have to load it from the // stack, since we don't know in which slot we can find it. frame topframe(csp, (address)0x8); if (os::is_first_C_frame(&topframe)) { // Stack is not walkable. return frame(); } else { frame senderFrame = os::get_sender_for_C_frame(&topframe); assert(senderFrame.pc() != NULL, "Sender pc should not be NULL"); // Return sender of sender of current topframe which hopefully // both have pc != NULL. #ifdef _NMT_NOINLINE_ // Is set in slowdebug builds. // Current_stack_pointer is not inlined, we must pop one more frame. frame tmp = os::get_sender_for_C_frame(&topframe); return os::get_sender_for_C_frame(&tmp); #else return os::get_sender_for_C_frame(&topframe); #endif } } // Utility functions extern "C" JNIEXPORT int JVM_handle_linux_signal(int sig, siginfo_t* info, void* ucVoid, int abort_if_unrecognized) { ucontext_t* uc = (ucontext_t*) ucVoid; Thread* t = Thread::current_or_null_safe(); // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away // (no destructors can be run). os::ThreadCrashProtection::check_crash_protection(sig, t); SignalHandlerMark shm(t); // Note: it's not uncommon that JNI code uses signal/sigset to install // then restore certain signal handler (e.g. to temporarily block SIGPIPE, // or have a SIGILL handler when detecting CPU type). When that happens, // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To // avoid unnecessary crash when libjsig is not preloaded, try handle signals // that do not require siginfo/ucontext first. if (sig == SIGPIPE) { if (os::Linux::chained_handler(sig, info, ucVoid)) { return true; } else { if (PrintMiscellaneous && (WizardMode || Verbose)) { warning("Ignoring SIGPIPE - see bug 4229104"); } return true; } } #ifdef CAN_SHOW_REGISTERS_ON_ASSERT if ((sig == SIGSEGV || sig == SIGBUS) && info != NULL && info->si_addr == g_assert_poison) { handle_assert_poison_fault(ucVoid, info->si_addr); return 1; } #endif JavaThread* thread = NULL; VMThread* vmthread = NULL; if (os::Linux::signal_handlers_are_installed) { if (t != NULL) { if(t->is_Java_thread()) { thread = (JavaThread*)t; } else if(t->is_VM_thread()) { vmthread = (VMThread *)t; } } } // Moved SafeFetch32 handling outside thread!=NULL conditional block to make // it work if no associated JavaThread object exists. if (uc) { address const pc = os::Linux::ucontext_get_pc(uc); if (pc && StubRoutines::is_safefetch_fault(pc)) { os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc)); return true; } } // Decide if this trap can be handled by a stub. address stub = NULL; address pc = NULL; // Pc as retrieved from PSW. Usually points past failing instruction. address trap_pc = NULL; // Pc of the instruction causing the trap. //%note os_trap_1 if (info != NULL && uc != NULL && thread != NULL) { pc = os::Linux::ucontext_get_pc(uc); if (TraceTraps) { tty->print_cr(" pc at " INTPTR_FORMAT, p2i(pc)); } if ((unsigned long)(pc - (address)info->si_addr) <= (unsigned long)Assembler::instr_maxlen() ) { trap_pc = (address)info->si_addr; if (TraceTraps) { tty->print_cr("trap_pc at " INTPTR_FORMAT, p2i(trap_pc)); } } // Handle ALL stack overflow variations here if (sig == SIGSEGV) { address addr = (address)info->si_addr; // Address causing SIGSEGV, usually mem ref target. // Check if fault address is within thread stack. if (thread->on_local_stack(addr)) { // stack overflow if (thread->in_stack_yellow_reserved_zone(addr)) { if (thread->thread_state() == _thread_in_Java) { if (thread->in_stack_reserved_zone(addr)) { frame fr; if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) { assert(fr.is_java_frame(), "Must be a Javac frame"); frame activation = SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr); if (activation.sp() != NULL) { thread->disable_stack_reserved_zone(); if (activation.is_interpreted_frame()) { thread->set_reserved_stack_activation((address)activation.fp()); } else { thread->set_reserved_stack_activation((address)activation.unextended_sp()); } return 1; } } } // Throw a stack overflow exception. // Guard pages will be reenabled while unwinding the stack. thread->disable_stack_yellow_reserved_zone(); stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW); } else { // Thread was in the vm or native code. Return and try to finish. thread->disable_stack_yellow_reserved_zone(); return 1; } } else if (thread->in_stack_red_zone(addr)) { // Fatal red zone violation. Disable the guard pages and fall through // to handle_unexpected_exception way down below. thread->disable_stack_red_zone(); tty->print_raw_cr("An irrecoverable stack overflow has occurred."); // This is a likely cause, but hard to verify. Let's just print // it as a hint. tty->print_raw_cr("Please check if any of your loaded .so files has " "enabled executable stack (see man page execstack(8))"); } else { // Accessing stack address below sp may cause SEGV if current // thread has MAP_GROWSDOWN stack. This should only happen when // current thread was created by user code with MAP_GROWSDOWN flag // and then attached to VM. See notes in os_linux.cpp. if (thread->osthread()->expanding_stack() == 0) { thread->osthread()->set_expanding_stack(); if (os::Linux::manually_expand_stack(thread, addr)) { thread->osthread()->clear_expanding_stack(); return 1; } thread->osthread()->clear_expanding_stack(); } else { fatal("recursive segv. expanding stack."); } } } } if (thread->thread_state() == _thread_in_Java) { // Java thread running in Java code => find exception handler if any // a fault inside compiled code, the interpreter, or a stub // Handle signal from NativeJump::patch_verified_entry(). if (sig == SIGILL && nativeInstruction_at(pc)->is_sigill_zombie_not_entrant()) { if (TraceTraps) { tty->print_cr("trap: zombie_not_entrant (SIGILL)"); } stub = SharedRuntime::get_handle_wrong_method_stub(); } else if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) { if (TraceTraps) { tty->print_cr("trap: safepoint_poll at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc)); } stub = SharedRuntime::get_poll_stub(pc); // Info->si_addr only points to the page base address, so we // must extract the real si_addr from the instruction and the // ucontext. assert(((NativeInstruction*)pc)->is_safepoint_poll(), "must be safepoint poll"); const address real_si_addr = ((NativeInstruction*)pc)->get_poll_address(uc); } // SIGTRAP-based implicit null check in compiled code. else if ((sig == SIGFPE) && TrapBasedNullChecks && (trap_pc != NULL) && Assembler::is_sigtrap_zero_check(trap_pc)) { if (TraceTraps) { tty->print_cr("trap: NULL_CHECK at " INTPTR_FORMAT " (SIGFPE)", p2i(trap_pc)); } stub = SharedRuntime::continuation_for_implicit_exception(thread, trap_pc, SharedRuntime::IMPLICIT_NULL); } else if (sig == SIGSEGV && ImplicitNullChecks && CodeCache::contains((void*) pc) && MacroAssembler::uses_implicit_null_check(info->si_addr)) { if (TraceTraps) { tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc)); } stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); } // SIGTRAP-based implicit range check in compiled code. else if (sig == SIGFPE && TrapBasedRangeChecks && (trap_pc != NULL) && Assembler::is_sigtrap_range_check(trap_pc)) { if (TraceTraps) { tty->print_cr("trap: RANGE_CHECK at " INTPTR_FORMAT " (SIGFPE)", p2i(trap_pc)); } stub = SharedRuntime::continuation_for_implicit_exception(thread, trap_pc, SharedRuntime::IMPLICIT_NULL); } else if (sig == SIGFPE && info->si_code == FPE_INTDIV) { stub = SharedRuntime::continuation_for_implicit_exception(thread, trap_pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO); } else if (sig == SIGBUS) { // BugId 4454115: A read from a MappedByteBuffer can fault here if the // underlying file has been truncated. Do not crash the VM in such a case. CodeBlob* cb = CodeCache::find_blob_unsafe(pc); CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL; if (nm != NULL && nm->has_unsafe_access()) { // We don't really need a stub here! Just set the pending exeption and // continue at the next instruction after the faulting read. Returning // garbage from this read is ok. thread->set_pending_unsafe_access_error(); uc->uc_mcontext.psw.addr = ((unsigned long)pc) + Assembler::instr_len(pc); return true; } } } else { // thread->thread_state() != _thread_in_Java if ((sig == SIGILL) && VM_Version::is_determine_features_test_running()) { // SIGILL must be caused by VM_Version::determine_features() // when attempting to execute a non-existing instruction. //*(int *) (pc-6)=0; // Patch instruction to 0 to indicate that it causes a SIGILL. // Flushing of icache is not necessary. stub = pc; // Continue with next instruction. } else if ((sig == SIGFPE) && VM_Version::is_determine_features_test_running()) { // SIGFPE is known to be caused by trying to execute a vector instruction // when the vector facility is installed, but operating system support is missing. VM_Version::reset_has_VectorFacility(); stub = pc; // Continue with next instruction. } else if (thread->thread_state() == _thread_in_vm && sig == SIGBUS && thread->doing_unsafe_access()) { // We don't really need a stub here! Just set the pending exeption and // continue at the next instruction after the faulting read. Returning // garbage from this read is ok. thread->set_pending_unsafe_access_error(); os::Linux::ucontext_set_pc(uc, pc + Assembler::instr_len(pc)); return true; } } // Check to see if we caught the safepoint code in the // process of write protecting the memory serialization page. // It write enables the page immediately after protecting it // so we can just return to retry the write. // Info->si_addr need not be the exact address, it is only // guaranteed to be on the same page as the address that caused // the SIGSEGV. if ((sig == SIGSEGV) && !UseMembar && (os::get_memory_serialize_page() == (address)((uintptr_t)info->si_addr & ~(os::vm_page_size()-1)))) { return true; } } if (stub != NULL) { // Save all thread context in case we need to restore it. if (thread != NULL) thread->set_saved_exception_pc(pc); os::Linux::ucontext_set_pc(uc, stub); return true; } // signal-chaining if (os::Linux::chained_handler(sig, info, ucVoid)) { return true; } if (!abort_if_unrecognized) { // caller wants another chance, so give it to him return false; } if (pc == NULL && uc != NULL) { pc = os::Linux::ucontext_get_pc(uc); } // unmask current signal sigset_t newset; sigemptyset(&newset); sigaddset(&newset, sig); sigprocmask(SIG_UNBLOCK, &newset, NULL); // Hand down correct pc for SIGILL, SIGFPE. pc from context // usually points to the instruction after the failing instruction. // Note: this should be combined with the trap_pc handling above, // because it handles the same issue. if (sig == SIGILL || sig == SIGFPE) { pc = (address)info->si_addr; } VMError::report_and_die(t, sig, pc, info, ucVoid); ShouldNotReachHere(); return false; } void os::Linux::init_thread_fpu_state(void) { // Nothing to do on z/Architecture. } int os::Linux::get_fpu_control_word(void) { // Nothing to do on z/Architecture. return 0; } void os::Linux::set_fpu_control_word(int fpu_control) { // Nothing to do on z/Architecture. } //////////////////////////////////////////////////////////////////////////////// // thread stack // Minimum usable stack sizes required to get to user code. Space for // HotSpot guard pages is added later. size_t os::Posix::_compiler_thread_min_stack_allowed = (52 DEBUG_ONLY(+ 32)) * K; size_t os::Posix::_java_thread_min_stack_allowed = (32 DEBUG_ONLY(+ 8)) * K; size_t os::Posix::_vm_internal_thread_min_stack_allowed = 32 * K; // Return default stack size for thr_type. size_t os::Posix::default_stack_size(os::ThreadType thr_type) { // Default stack size (compiler thread needs larger stack). size_t s = (thr_type == os::compiler_thread ? 4 * M : 1024 * K); return s; } ///////////////////////////////////////////////////////////////////////////// // helper functions for fatal error handler void os::print_context(outputStream *st, const void *context) { if (context == NULL) return; const ucontext_t* uc = (const ucontext_t*)context; st->print_cr("Processor state:"); st->print_cr("----------------"); st->print_cr(" ip = " INTPTR_FORMAT " ", uc->uc_mcontext.psw.addr); st->print_cr(" proc mask = " INTPTR_FORMAT " ", uc->uc_mcontext.psw.mask); st->print_cr(" fpc reg = 0x%8.8x " , uc->uc_mcontext.fpregs.fpc); st->cr(); st->print_cr("General Purpose Registers:"); st->print_cr("--------------------------"); for( int i = 0; i < 16; i+=2 ) { st->print(" r%-2d = " INTPTR_FORMAT " " , i, uc->uc_mcontext.gregs[i]); st->print(" r%-2d = " INTPTR_FORMAT " |", i+1, uc->uc_mcontext.gregs[i+1]); st->print(" r%-2d = %23.1ld " , i, uc->uc_mcontext.gregs[i]); st->print(" r%-2d = %23.1ld " , i+1, uc->uc_mcontext.gregs[i+1]); st->cr(); } st->cr(); st->print_cr("Access Registers:"); st->print_cr("-----------------"); for( int i = 0; i < 16; i+=2 ) { st->print(" ar%-2d = 0x%8.8x ", i, uc->uc_mcontext.aregs[i]); st->print(" ar%-2d = 0x%8.8x ", i+1, uc->uc_mcontext.aregs[i+1]); st->cr(); } st->cr(); st->print_cr("Float Registers:"); st->print_cr("----------------"); for (int i = 0; i < 16; i += 2) { st->print(" fr%-2d = " INTPTR_FORMAT " " , i, (int64_t)(uc->uc_mcontext.fpregs.fprs[i].d)); st->print(" fr%-2d = " INTPTR_FORMAT " |", i+1, (int64_t)(uc->uc_mcontext.fpregs.fprs[i+1].d)); st->print(" fr%-2d = %23.15e " , i, (uc->uc_mcontext.fpregs.fprs[i].d)); st->print(" fr%-2d = %23.15e " , i+1, (uc->uc_mcontext.fpregs.fprs[i+1].d)); st->cr(); } st->cr(); st->cr(); intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc); st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp)); print_hex_dump(st, (address)sp, (address)(sp + 128), sizeof(intptr_t)); st->cr(); // Note: it may be unsafe to inspect memory near pc. For example, pc may // point to garbage if entry point in an nmethod is corrupted. Leave // this at the end, and hope for the best. address pc = os::Linux::ucontext_get_pc(uc); if (Verbose) { st->print_cr("pc at " PTR_FORMAT, p2i(pc)); } st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc)); print_hex_dump(st, pc-64, pc+64, /*intrsize=*/4); st->cr(); } void os::print_register_info(outputStream *st, const void *context) { if (context == NULL) return; const ucontext_t *uc = (const ucontext_t*)context; st->print_cr("Register to memory mapping:"); st->cr(); st->print("pc ="); print_location(st, (intptr_t)uc->uc_mcontext.psw.addr); for (int i = 0; i < 16; i++) { st->print("r%-2d=", i); print_location(st, uc->uc_mcontext.gregs[i]); } st->cr(); } #ifndef PRODUCT void os::verify_stack_alignment() { } #endif int os::extra_bang_size_in_bytes() { // z/Architecture does not require the additional stack bang. return 0; }