/* * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2012, 2016 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. * */ // no precompiled headers #include "asm/assembler.inline.hpp" #include "classfile/classLoader.hpp" #include "classfile/systemDictionary.hpp" #include "classfile/vmSymbols.hpp" #include "code/codeCache.hpp" #include "code/icBuffer.hpp" #include "code/vtableStubs.hpp" #include "interpreter/interpreter.hpp" #include "jvm_linux.h" #include "memory/allocation.inline.hpp" #include "nativeInst_ppc.hpp" #include "os_share_linux.hpp" #include "prims/jniFastGetField.hpp" #include "prims/jvm.h" #include "prims/jvm_misc.hpp" #include "runtime/arguments.hpp" #include "runtime/extendedPC.hpp" #include "runtime/frame.inline.hpp" #include "runtime/interfaceSupport.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/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 `mr regno(csp), R1_SP': __asm__ __volatile__ ("mr %0, 1":"=r"(csp):); 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; } void os::initialize_thread(Thread *thread) { } // Frame information (pc, sp, fp) retrieved via ucontext // always looks like a C-frame according to the frame // conventions in frame_ppc64.hpp. address os::Linux::ucontext_get_pc(const ucontext_t * uc) { // On powerpc64, ucontext_t is not selfcontained but contains // a pointer to an optional substructure (mcontext_t.regs) containing the volatile // registers - NIP, among others. // This substructure may or may not be there depending where uc came from: // - if uc was handed over as the argument to a sigaction handler, a pointer to the // substructure was provided by the kernel when calling the signal handler, and // regs->nip can be accessed. // - if uc was filled by getcontext(), it is undefined - getcontext() does not fill // it because the volatile registers are not needed to make setcontext() work. // Hopefully it was zero'd out beforehand. guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_get_pc in sigaction context"); return (address)uc->uc_mcontext.regs->nip; } // modify PC in ucontext. // Note: Only use this for an ucontext handed down to a signal handler. See comment // in ucontext_get_pc. void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) { guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_set_pc in sigaction context"); uc->uc_mcontext.regs->nip = (unsigned long)pc; } intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) { return (intptr_t*)uc->uc_mcontext.regs->gpr[1/*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* fp = os::Linux::ucontext_get_fp(uc); intptr_t* sp = os::Linux::ucontext_get_sp(uc); *fr = frame(sp, (address)*sp); 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(NULL, NULL); } return frame(fr->sender_sp(), fr->sender_pc()); } frame os::current_frame() { intptr_t* csp = (intptr_t*) *((intptr_t*) os::current_stack_pointer()); // hack. frame topframe(csp, (address)0x8); // Return sender of sender of current topframe which hopefully // both have pc != NULL. frame tmp = os::get_sender_for_C_frame(&topframe); return os::get_sender_for_C_frame(&tmp); } // 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(); 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 { // Ignoring SIGPIPE - see bugs 4229104 return true; } } // Make the signal handler transaction-aware by checking the existence of a // second (transactional) context with MSR TS bits active. If the signal is // caught during a transaction, then just return to the HTM abort handler. // Please refer to Linux kernel document powerpc/transactional_memory.txt, // section "Signals". if (uc && uc->uc_link) { ucontext_t* second_uc = uc->uc_link; // MSR TS bits are 29 and 30 (Power ISA, v2.07B, Book III-S, pp. 857-858, // 3.2.1 "Machine State Register"), however note that ISA notation for bit // numbering is MSB 0, so for normal bit numbering (LSB 0) they come to be // bits 33 and 34. It's not related to endianness, just a notation matter. if (second_uc->uc_mcontext.regs->msr & 0x600000000) { if (TraceTraps) { tty->print_cr("caught signal in transaction, " "ignoring to jump to abort handler"); } // Return control to the HTM abort handler. return true; } } 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; //%note os_trap_1 if (info != NULL && uc != NULL && thread != NULL) { pc = (address) os::Linux::ucontext_get_pc(uc); // Handle ALL stack overflow variations here if (sig == SIGSEGV) { // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see // comment below). Use get_stack_bang_address instead of si_addr. address addr = ((NativeInstruction*)pc)->get_stack_bang_address(uc); // 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 // A VM-related SIGILL may only occur if we are not in the zero page. // On AIX, we get a SIGILL if we jump to 0x0 or to somewhere else // in the zero page, because it is filled with 0x0. We ignore // explicit SIGILLs in the zero page. if (sig == SIGILL && (pc < (address) 0x200)) { if (TraceTraps) { tty->print_raw_cr("SIGILL happened inside zero page."); } goto report_and_die; } CodeBlob *cb = NULL; // Handle signal from NativeJump::patch_verified_entry(). if (( TrapBasedNotEntrantChecks && sig == SIGTRAP && nativeInstruction_at(pc)->is_sigtrap_zombie_not_entrant()) || (!TrapBasedNotEntrantChecks && sig == SIGILL && nativeInstruction_at(pc)->is_sigill_zombie_not_entrant())) { if (TraceTraps) { tty->print_cr("trap: zombie_not_entrant (%s)", (sig == SIGTRAP) ? "SIGTRAP" : "SIGILL"); } stub = SharedRuntime::get_handle_wrong_method_stub(); } else if (sig == SIGSEGV && // A linux-ppc64 kernel before 2.6.6 doesn't set si_addr on some segfaults // in 64bit mode (cf. http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.6), // especially when we try to read from the safepoint polling page. So the check // (address)info->si_addr == os::get_standard_polling_page() // doesn't work for us. We use: ((NativeInstruction*)pc)->is_safepoint_poll() && CodeCache::contains((void*) pc) && ((cb = CodeCache::find_blob(pc)) != NULL) && cb->is_compiled()) { if (TraceTraps) { tty->print_cr("trap: safepoint_poll at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc)); } stub = SharedRuntime::get_poll_stub(pc); } // SIGTRAP-based ic miss check in compiled code. else if (sig == SIGTRAP && TrapBasedICMissChecks && nativeInstruction_at(pc)->is_sigtrap_ic_miss_check()) { if (TraceTraps) { tty->print_cr("trap: ic_miss_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc)); } stub = SharedRuntime::get_ic_miss_stub(); } // SIGTRAP-based implicit null check in compiled code. else if (sig == SIGTRAP && TrapBasedNullChecks && nativeInstruction_at(pc)->is_sigtrap_null_check()) { if (TraceTraps) { tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc)); } stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); } // SIGSEGV-based implicit null check in compiled code. else if (sig == SIGSEGV && ImplicitNullChecks && CodeCache::contains((void*) pc) && !MacroAssembler::needs_explicit_null_check((intptr_t) 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); } #ifdef COMPILER2 // SIGTRAP-based implicit range check in compiled code. else if (sig == SIGTRAP && TrapBasedRangeChecks && nativeInstruction_at(pc)->is_sigtrap_range_check()) { if (TraceTraps) { tty->print_cr("trap: range_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc)); } stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL); } #endif 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()) { address next_pc = pc + 4; next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc); os::Linux::ucontext_set_pc(uc, next_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(). *(int *)pc = 0; // patch instruction to 0 to indicate that it causes a SIGILL, // flushing of icache is not necessary. stub = pc + 4; // continue with next instruction. } else if (thread->thread_state() == _thread_in_vm && sig == SIGBUS && thread->doing_unsafe_access()) { address next_pc = pc + 4; next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc); os::Linux::ucontext_set_pc(uc, pc + 4); 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. if ((sig == SIGSEGV) && // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see comment above). // Use is_memory_serialization instead of si_addr. ((NativeInstruction*)pc)->is_memory_serialization(thread, ucVoid)) { // Synchronization problem in the pseudo memory barrier code (bug id 6546278) // Block current thread until the memory serialize page permission restored. os::block_on_serialize_page_trap(); 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); } report_and_die: // unmask current signal sigset_t newset; sigemptyset(&newset); sigaddset(&newset, sig); sigprocmask(SIG_UNBLOCK, &newset, NULL); VMError::report_and_die(t, sig, pc, info, ucVoid); ShouldNotReachHere(); return false; } void os::Linux::init_thread_fpu_state(void) { // Disable FP exceptions. __asm__ __volatile__ ("mtfsfi 6,0"); } int os::Linux::get_fpu_control_word(void) { // x86 has problems with FPU precision after pthread_cond_timedwait(). // nothing to do on ppc64. return 0; } void os::Linux::set_fpu_control_word(int fpu_control) { // x86 has problems with FPU precision after pthread_cond_timedwait(). // nothing to do on ppc64. } //////////////////////////////////////////////////////////////////////////////// // thread stack // These sizes exclude libc stack guard pages, but include // the HotSpot guard pages. size_t os::Posix::_compiler_thread_min_stack_allowed = 384 * K; size_t os::Posix::_java_thread_min_stack_allowed = 384 * K; size_t os::Posix::_vm_internal_thread_min_stack_allowed = 128 * 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("Registers:"); st->print("pc =" INTPTR_FORMAT " ", uc->uc_mcontext.regs->nip); st->print("lr =" INTPTR_FORMAT " ", uc->uc_mcontext.regs->link); st->print("ctr=" INTPTR_FORMAT " ", uc->uc_mcontext.regs->ctr); st->cr(); for (int i = 0; i < 32; i++) { st->print("r%-2d=" INTPTR_FORMAT " ", i, uc->uc_mcontext.regs->gpr[i]); if (i % 3 == 2) 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); st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc)); print_hex_dump(st, pc - 64, pc + 64, /*instrsize=*/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(); // this is only for the "general purpose" registers for (int i = 0; i < 32; i++) { st->print("r%-2d=", i); print_location(st, uc->uc_mcontext.regs->gpr[i]); } st->cr(); } extern "C" { int SpinPause() { return 0; } } #ifndef PRODUCT void os::verify_stack_alignment() { assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment"); } #endif int os::extra_bang_size_in_bytes() { // PPC does not require the additional stack bang. return 0; }