/*
* 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 <sys/types.h>
# include <sys/mman.h>
# include <pthread.h>
# include <signal.h>
# include <errno.h>
# include <dlfcn.h>
# include <stdlib.h>
# include <stdio.h>
# include <unistd.h>
# include <sys/resource.h>
# include <pthread.h>
# include <sys/stat.h>
# include <sys/time.h>
# include <sys/utsname.h>
# include <sys/socket.h>
# include <sys/wait.h>
# include <pwd.h>
# include <poll.h>
# include <ucontext.h>
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;
}
}
}
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);
print_instructions(st, pc, /*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;
}