JDK14/Java14源码在线阅读
/*
* Copyright (c) 2008, 2019, Oracle and/or its affiliates. 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 "jvm.h"
#include "assembler_arm.inline.hpp"
#include "classfile/classLoader.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
#include "code/icBuffer.hpp"
#include "code/vtableStubs.hpp"
#include "interpreter/interpreter.hpp"
#include "memory/allocation.inline.hpp"
#include "nativeInst_arm.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/timer.hpp"
#include "utilities/debug.hpp"
#include "utilities/events.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>
# include <fpu_control.h>
# include <asm/ptrace.h>
#define SPELL_REG_SP "sp"
// Don't #define SPELL_REG_FP for thumb because it is not safe to use, so this makes sure we never fetch it.
#ifndef __thumb__
#define SPELL_REG_FP "fp"
#endif
address os::current_stack_pointer() {
register address sp __asm__ (SPELL_REG_SP);
return sp;
}
char* os::non_memory_address_word() {
// Must never look like an address returned by reserve_memory
return (char*) -1;
}
#if NGREG == 16
// These definitions are based on the observation that until
// the certain version of GCC mcontext_t was defined as
// a structure containing gregs[NGREG] array with 16 elements.
// In later GCC versions mcontext_t was redefined as struct sigcontext,
// along with NGREG constant changed to 18.
#define arm_pc gregs[15]
#define arm_sp gregs[13]
#define arm_fp gregs[11]
#define arm_r0 gregs[0]
#endif
#define ARM_REGS_IN_CONTEXT 16
address os::Linux::ucontext_get_pc(const ucontext_t* uc) {
return (address)uc->uc_mcontext.arm_pc;
}
void os::Linux::ucontext_set_pc(ucontext_t* uc, address pc) {
uc->uc_mcontext.arm_pc = (uintx)pc;
}
intptr_t* os::Linux::ucontext_get_sp(const ucontext_t* uc) {
return (intptr_t*)uc->uc_mcontext.arm_sp;
}
intptr_t* os::Linux::ucontext_get_fp(const ucontext_t* uc) {
return (intptr_t*)uc->uc_mcontext.arm_fp;
}
bool is_safe_for_fp(address pc) {
#ifdef __thumb__
if (CodeCache::find_blob(pc) != NULL) {
return true;
}
// For thumb C frames, given an fp we have no idea how to access the frame contents.
return false;
#else
// Calling os::address_is_in_vm() here leads to a dladdr call. Calling any libc
// function during os::get_native_stack() can result in a deadlock if JFR is
// enabled. For now, be more lenient and allow all pc's. There are other
// frame sanity checks in shared code, and to date they have been sufficient
// for other platforms.
//return os::address_is_in_vm(pc);
return true;
#endif
}
// For Forte Analyzer AsyncGetCallTrace profiling support - thread
// is currently interrupted by SIGPROF.
// os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
// frames. Currently we don't do that on Linux, so it's the same as
// os::fetch_frame_from_context().
ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
assert(thread != NULL, "just checking");
assert(ret_sp != NULL, "just checking");
assert(ret_fp != NULL, "just checking");
return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
}
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) {
intptr_t* fp = os::Linux::ucontext_get_fp(uc);
#ifndef __thumb__
if (CodeCache::find_blob(epc.pc()) == NULL) {
// It's a C frame. We need to adjust the fp.
fp += os::C_frame_offset;
}
#endif
// Clear FP when stack walking is dangerous so that
// the frame created will not be walked.
// However, ensure FP is set correctly when reliable and
// potentially necessary.
if (!is_safe_for_fp(epc.pc())) {
// FP unreliable
fp = (intptr_t *)NULL;
}
*ret_fp = fp;
}
} 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, fp, epc.pc());
}
frame os::get_sender_for_C_frame(frame* fr) {
#ifdef __thumb__
// We can't reliably get anything from a thumb C frame.
return frame();
#else
address pc = fr->sender_pc();
if (! is_safe_for_fp(pc)) {
return frame(fr->sender_sp(), (intptr_t *)NULL, pc);
} else {
return frame(fr->sender_sp(), fr->link() + os::C_frame_offset, pc);
}
#endif
}
//
// This actually returns two frames up. It does not return os::current_frame(),
// which is the actual current frame. Nor does it return os::get_native_stack(),
// which is the caller. It returns whoever called os::get_native_stack(). Not
// very intuitive, but consistent with how this API is implemented on other
// platforms.
//
frame os::current_frame() {
#ifdef __thumb__
// We can't reliably get anything from a thumb C frame.
return frame();
#else
register intptr_t* fp __asm__ (SPELL_REG_FP);
// fp is for os::current_frame. We want the fp for our caller.
frame myframe((intptr_t*)os::current_stack_pointer(), fp + os::C_frame_offset,
CAST_FROM_FN_PTR(address, os::current_frame));
frame caller_frame = os::get_sender_for_C_frame(&myframe);
if (os::is_first_C_frame(&caller_frame)) {
// stack is not walkable
// Assert below was added because it does not seem like this can ever happen.
// How can this frame ever be the first C frame since it is called from C code?
// If it does ever happen, undo the assert and comment here on when/why it happens.
assert(false, "this should never happen");
return frame();
}
// return frame for our caller's caller
return os::get_sender_for_C_frame(&caller_frame);
#endif
}
extern "C" address check_vfp_fault_instr;
extern "C" address check_vfp3_32_fault_instr;
extern "C" address check_simd_fault_instr;
extern "C" address check_mp_ext_fault_instr;
address check_vfp_fault_instr = NULL;
address check_vfp3_32_fault_instr = NULL;
address check_simd_fault_instr = NULL;
address check_mp_ext_fault_instr = NULL;
// Utility functions
extern "C" 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);
if (sig == SIGILL &&
((info->si_addr == (caddr_t)check_simd_fault_instr)
|| info->si_addr == (caddr_t)check_vfp_fault_instr
|| info->si_addr == (caddr_t)check_vfp3_32_fault_instr
|| info->si_addr == (caddr_t)check_mp_ext_fault_instr)) {
// skip faulty instruction + instruction that sets return value to
// success and set return value to failure.
os::Linux::ucontext_set_pc(uc, (address)info->si_addr + 8);
uc->uc_mcontext.arm_r0 = 0;
return true;
}
// 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 || sig == SIGXFSZ) {
// allow chained handler to go first
if (os::Linux::chained_handler(sig, info, ucVoid)) {
return true;
} else {
// Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
return true;
}
}
#ifdef CAN_SHOW_REGISTERS_ON_ASSERT
if ((sig == SIGSEGV || sig == SIGBUS) && info != NULL && info->si_addr == g_assert_poison) {
if (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;
}
}
}
address stub = NULL;
address pc = NULL;
bool unsafe_access = false;
if (info != NULL && uc != NULL && thread != NULL) {
pc = (address) os::Linux::ucontext_get_pc(uc);
// Handle ALL stack overflow variations here
if (sig == SIGSEGV) {
address addr = (address) info->si_addr;
if (StubRoutines::is_safefetch_fault(pc)) {
os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
return 1;
}
// check if fault address is within thread stack
if (addr < thread->stack_base() &&
addr >= thread->stack_base() - thread->stack_size()) {
// stack overflow
if (thread->in_stack_yellow_reserved_zone(addr)) {
thread->disable_stack_yellow_reserved_zone();
if (thread->thread_state() == _thread_in_Java) {
// Throw a stack overflow exception. Guard pages will be reenabled
// while unwinding the stack.
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.
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.");
} 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
if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
stub = SharedRuntime::get_poll_stub(pc);
} 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()) || (thread->doing_unsafe_access() && UnsafeCopyMemory::contains_pc(pc))) {
unsafe_access = true;
}
} else if (sig == SIGSEGV &&
MacroAssembler::uses_implicit_null_check(info->si_addr)) {
// Determination of interpreter/vtable stub/compiled code null exception
CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
if (cb != NULL) {
stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
}
} else if (sig == SIGILL && *(int *)pc == NativeInstruction::zombie_illegal_instruction) {
// Zombie
stub = SharedRuntime::get_handle_wrong_method_stub();
}
} else if ((thread->thread_state() == _thread_in_vm ||
thread->thread_state() == _thread_in_native) &&
sig == SIGBUS && thread->doing_unsafe_access()) {
unsafe_access = true;
}
// 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;
}
}
}
if (unsafe_access && stub == NULL) {
// it can be an unsafe access and we haven't found
// any other suitable exception reason,
// so assume it is an unsafe access.
address next_pc = pc + Assembler::InstructionSize;
if (UnsafeCopyMemory::contains_pc(pc)) {
next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
}
#ifdef __thumb__
if (uc->uc_mcontext.arm_cpsr & PSR_T_BIT) {
next_pc = (address)((intptr_t)next_pc | 0x1);
}
#endif
stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
}
if (stub != NULL) {
#ifdef __thumb__
if (uc->uc_mcontext.arm_cpsr & PSR_T_BIT) {
intptr_t p = (intptr_t)pc | 0x1;
pc = (address)p;
// Clear Thumb mode bit if we're redirected into the ARM ISA based code
if (((intptr_t)stub & 0x1) == 0) {
uc->uc_mcontext.arm_cpsr &= ~PSR_T_BIT;
}
} else {
// No Thumb2 compiled stubs are triggered from ARM ISA compiled JIT'd code today.
// The support needs to be added if that changes
assert((((intptr_t)stub & 0x1) == 0), "can't return to Thumb code");
}
#endif
// 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);
VMError::report_and_die(t, sig, pc, info, ucVoid);
ShouldNotReachHere();
return false;
}
void os::Linux::init_thread_fpu_state(void) {
os::setup_fpu();
}
int os::Linux::get_fpu_control_word(void) {
return 0;
}
void os::Linux::set_fpu_control_word(int fpu_control) {
// Nothing to do
}
void os::setup_fpu() {
#if !defined(__SOFTFP__) && defined(__VFP_FP__)
// Turn on IEEE-754 compliant VFP mode
__asm__ volatile (
"mov %%r0, #0;"
"fmxr fpscr, %%r0"
: /* no output */ : /* no input */ : "r0"
);
#endif
}
bool os::is_allocatable(size_t bytes) {
return true;
}
////////////////////////////////////////////////////////////////////////////////
// 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 = (32 DEBUG_ONLY(+ 4)) * K;
size_t os::Posix::_java_thread_min_stack_allowed = (32 DEBUG_ONLY(+ 4)) * K;
size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * 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 ? 2 * M : 512 * 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:");
intx* reg_area = (intx*)&uc->uc_mcontext.arm_r0;
for (int r = 0; r < ARM_REGS_IN_CONTEXT; r++) {
st->print_cr(" %-3s = " INTPTR_FORMAT, as_Register(r)->name(), reg_area[r]);
}
#define U64_FORMAT "0x%016llx"
// now print flag register
st->print_cr(" %-4s = 0x%08lx", "cpsr",uc->uc_mcontext.arm_cpsr);
st->cr();
intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
st->print_cr("Top of Stack: (sp=" INTPTR_FORMAT ")", p2i(sp));
print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), 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, Assembler::InstructionSize);
st->cr();
}
void os::print_register_info(outputStream *st, const void *context) {
if (context == NULL) return;
const ucontext_t *uc = (const ucontext_t*)context;
intx* reg_area = (intx*)&uc->uc_mcontext.arm_r0;
st->print_cr("Register to memory mapping:");
st->cr();
for (int r = 0; r < ARM_REGS_IN_CONTEXT; r++) {
st->print_cr(" %-3s = " INTPTR_FORMAT, as_Register(r)->name(), reg_area[r]);
print_location(st, reg_area[r]);
st->cr();
}
st->cr();
}
typedef int64_t cmpxchg_long_func_t(int64_t, int64_t, volatile int64_t*);
cmpxchg_long_func_t* os::atomic_cmpxchg_long_func = os::atomic_cmpxchg_long_bootstrap;
int64_t os::atomic_cmpxchg_long_bootstrap(int64_t compare_value, int64_t exchange_value, volatile int64_t* dest) {
// try to use the stub:
cmpxchg_long_func_t* func = CAST_TO_FN_PTR(cmpxchg_long_func_t*, StubRoutines::atomic_cmpxchg_long_entry());
if (func != NULL) {
os::atomic_cmpxchg_long_func = func;
return (*func)(compare_value, exchange_value, dest);
}
assert(Threads::number_of_threads() == 0, "for bootstrap only");
int64_t old_value = *dest;
if (old_value == compare_value)
*dest = exchange_value;
return old_value;
}
typedef int64_t load_long_func_t(const volatile int64_t*);
load_long_func_t* os::atomic_load_long_func = os::atomic_load_long_bootstrap;
int64_t os::atomic_load_long_bootstrap(const volatile int64_t* src) {
// try to use the stub:
load_long_func_t* func = CAST_TO_FN_PTR(load_long_func_t*, StubRoutines::atomic_load_long_entry());
if (func != NULL) {
os::atomic_load_long_func = func;
return (*func)(src);
}
assert(Threads::number_of_threads() == 0, "for bootstrap only");
int64_t old_value = *src;
return old_value;
}
typedef void store_long_func_t(int64_t, volatile int64_t*);
store_long_func_t* os::atomic_store_long_func = os::atomic_store_long_bootstrap;
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