JDK14/Java14源码在线阅读
/*
* Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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// 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/codeCache.hpp"
#include "code/icBuffer.hpp"
#include "code/vtableStubs.hpp"
#include "interpreter/interpreter.hpp"
#include "memory/allocation.inline.hpp"
#include "nativeInst_ppc.hpp"
#include "os_share_aix.hpp"
#include "prims/jniFastGetField.hpp"
#include "prims/jvm_misc.hpp"
#include "porting_aix.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/safepointMechanism.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"
#ifdef COMPILER1
#include "c1/c1_Runtime1.hpp"
#endif
#ifdef COMPILER2
#include "opto/runtime.hpp"
#endif
// put OS-includes here
# include <ucontext.h>
address os::current_stack_pointer() {
address csp;
#if !defined(USE_XLC_BUILTINS)
// inline assembly for `mr regno(csp), R1_SP':
__asm__ __volatile__ ("mr %0, 1":"=r"(csp):);
#else
csp = (address) __builtin_frame_address(0);
#endif
return 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_ppc.hpp.
address os::Aix::ucontext_get_pc(const ucontext_t * uc) {
return (address)uc->uc_mcontext.jmp_context.iar;
}
intptr_t* os::Aix::ucontext_get_sp(const ucontext_t * uc) {
// gpr1 holds the stack pointer on aix
return (intptr_t*)uc->uc_mcontext.jmp_context.gpr[1/*REG_SP*/];
}
intptr_t* os::Aix::ucontext_get_fp(const ucontext_t * uc) {
return NULL;
}
void os::Aix::ucontext_set_pc(ucontext_t* uc, address new_pc) {
uc->uc_mcontext.jmp_context.iar = (uint64_t) new_pc;
}
static address ucontext_get_lr(const ucontext_t * uc) {
return (address)uc->uc_mcontext.jmp_context.lr;
}
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::Aix::ucontext_get_pc(uc));
if (ret_sp) *ret_sp = os::Aix::ucontext_get_sp(uc);
if (ret_fp) *ret_fp = os::Aix::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);
// Avoid crash during crash if pc broken.
if (epc.pc()) {
frame fr(sp, epc.pc());
return fr;
}
frame fr(sp);
return fr;
}
bool os::Aix::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
address pc = (address) os::Aix::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::Aix::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() == NULL) {
// 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_aix_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_aix_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::Aix::chained_handler(sig, info, ucVoid)) {
return 1;
} else {
// Ignoring SIGPIPE - see bugs 4229104
return 1;
}
}
JavaThread* thread = NULL;
VMThread* vmthread = NULL;
if (os::Aix::signal_handlers_are_installed) {
if (t != NULL) {
if(t->is_Java_thread()) {
thread = (JavaThread*)t;
}
else if(t->is_VM_thread()) {
vmthread = (VMThread *)t;
}
}
}
// Decide if this trap can be handled by a stub.
address stub = NULL;
// retrieve program counter
address const pc = uc ? os::Aix::ucontext_get_pc(uc) : NULL;
// retrieve crash address
address const addr = info ? (const address) info->si_addr : NULL;
// SafeFetch 32 handling:
// - make it work if _thread is null
// - make it use the standard os::...::ucontext_get/set_pc APIs
if (uc) {
address const pc = os::Aix::ucontext_get_pc(uc);
if (pc && StubRoutines::is_safefetch_fault(pc)) {
os::Aix::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
return true;
}
}
if (info == NULL || uc == NULL || thread == NULL && vmthread == NULL) {
goto run_chained_handler;
}
// If we are a java thread...
if (thread != NULL) {
// Handle ALL stack overflow variations here
if (sig == SIGSEGV && thread->on_local_stack(addr)) {
// stack overflow
//
// If we are in a yellow zone and we are inside java, we disable the yellow zone and
// throw a stack overflow exception.
// If we are in native code or VM C code, we report-and-die. The original coding tried
// to continue with yellow zone disabled, but that doesn't buy us much and prevents
// hs_err_pid files.
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::Aix::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);
goto run_stub;
} 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.");
goto report_and_die;
} else {
// This means a segv happened inside our stack, but not in
// the guarded zone. I'd like to know when this happens,
tty->print_raw_cr("SIGSEGV happened inside stack but outside yellow and red zone.");
goto report_and_die;
}
} // end handle SIGSEGV inside stack boundaries
if (thread->thread_state() == _thread_in_Java) {
// Java thread running in Java code
// The following signals are used for communicating VM events:
//
// SIGILL: the compiler generates illegal opcodes
// at places where it wishes to interrupt the VM:
// Safepoints, Unreachable Code, Entry points of Zombie methods,
// This results in a SIGILL with (*pc) == inserted illegal instruction.
//
// (so, SIGILLs with a pc inside the zero page are real errors)
//
// SIGTRAP:
// The ppc trap instruction raises a SIGTRAP and is very efficient if it
// does not trap. It is used for conditional branches that are expected
// to be never taken. These are:
// - zombie methods
// - IC (inline cache) misses.
// - null checks leading to UncommonTraps.
// - range checks leading to Uncommon Traps.
// On Aix, these are especially null checks, as the ImplicitNullCheck
// optimization works only in rare cases, as the page at address 0 is only
// write protected. //
// Note: !UseSIGTRAP is used to prevent SIGTRAPS altogether, to facilitate debugging.
//
// SIGSEGV:
// used for safe point polling:
// To notify all threads that they have to reach a safe point, safe point polling is used:
// All threads poll a certain mapped memory page. Normally, this page has read access.
// If the VM wants to inform the threads about impending safe points, it puts this
// page to read only ("poisens" the page), and the threads then reach a safe point.
// used for null checks:
// If the compiler finds a store it uses it for a null check. Unfortunately this
// happens rarely. In heap based and disjoint base compressd oop modes also loads
// are used for null checks.
// 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;
}
// 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();
goto run_stub;
}
else if ((SafepointMechanism::uses_thread_local_poll() && USE_POLL_BIT_ONLY)
? (sig == SIGTRAP && ((NativeInstruction*)pc)->is_safepoint_poll())
: (sig == SIGSEGV && os::is_poll_address(addr))) {
if (TraceTraps) {
tty->print_cr("trap: safepoint_poll at " INTPTR_FORMAT " (%s)", p2i(pc),
(SafepointMechanism::uses_thread_local_poll() && USE_POLL_BIT_ONLY) ? "SIGTRAP" : "SIGSEGV");
}
stub = SharedRuntime::get_poll_stub(pc);
goto run_stub;
}
// 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)", pc);
}
stub = SharedRuntime::get_ic_miss_stub();
goto run_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)", pc);
}
stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
goto run_stub;
}
// SIGSEGV-based implicit null check in compiled code.
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)", 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)", pc);
}
stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
goto run_stub;
}
#endif
else if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
if (TraceTraps) {
tty->print_raw_cr("Fix SIGFPE handler, trying divide by zero handler.");
}
stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
goto run_stub;
}
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->as_compiled_method_or_null();
bool is_unsafe_arraycopy = (thread->doing_unsafe_access() && UnsafeCopyMemory::contains_pc(pc));
if ((nm != NULL && nm->has_unsafe_access()) || is_unsafe_arraycopy) {
address next_pc = pc + 4;
if (is_unsafe_arraycopy) {
next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
}
next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc);
os::Aix::ucontext_set_pc(uc, next_pc);
return 1;
}
}
}
else { // thread->thread_state() != _thread_in_Java
// Detect CPU features. This is only done at the very start of the VM. Later, the
// VM_Version::is_determine_features_test_running() flag should be false.
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.
goto run_stub;
}
else if ((thread->thread_state() == _thread_in_vm ||
thread->thread_state() == _thread_in_native) &&
sig == SIGBUS && thread->doing_unsafe_access()) {
address next_pc = pc + 4;
if (UnsafeCopyMemory::contains_pc(pc)) {
next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
}
next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc);
os::Aix::ucontext_set_pc(uc, next_pc);
return 1;
}
}
// jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
// and the heap gets shrunk before the field access.
if ((sig == SIGSEGV) || (sig == SIGBUS)) {
address addr = JNI_FastGetField::find_slowcase_pc(pc);
if (addr != (address)-1) {
stub = addr;
}
}
}
run_stub:
// One of the above code blocks ininitalized the stub, so we want to
// delegate control to that stub.
if (stub != NULL) {
// Save all thread context in case we need to restore it.
if (thread != NULL) thread->set_saved_exception_pc(pc);
os::Aix::ucontext_set_pc(uc, stub);
return 1;
}
run_chained_handler:
// signal-chaining
if (os::Aix::chained_handler(sig, info, ucVoid)) {
return 1;
}
if (!abort_if_unrecognized) {
// caller wants another chance, so give it to him
return 0;
}
report_and_die:
// Use sigthreadmask instead of sigprocmask on AIX and unmask current signal.
sigset_t newset;
sigemptyset(&newset);
sigaddset(&newset, sig);
sigthreadmask(SIG_UNBLOCK, &newset, NULL);
VMError::report_and_die(t, sig, pc, info, ucVoid);
ShouldNotReachHere();
return 0;
}
void os::Aix::init_thread_fpu_state(void) {
#if !defined(USE_XLC_BUILTINS)
// Disable FP exceptions.
__asm__ __volatile__ ("mtfsfi 6,0");
#else
__mtfsfi(6, 0);
#endif
}
////////////////////////////////////////////////////////////////////////////////
// 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 = 192 * K;
size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * 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 : 1 * M);
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;
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