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os_linux_zero.cpp
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os_linux_zero.cpp
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/*
* Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.
* 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_zero.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_zero.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/align.hpp"
#include "utilities/events.hpp"
#include "utilities/vmError.hpp"
// See stubGenerator_zero.cpp
#include <setjmp.h>
extern sigjmp_buf* get_jmp_buf_for_continuation();
address os::current_stack_pointer() {
// return the address of the current function
return (address)__builtin_frame_address(0);
}
frame os::get_sender_for_C_frame(frame* fr) {
ShouldNotCallThis();
return frame(NULL, NULL); // silence compile warning.
}
frame os::current_frame() {
// The only thing that calls this is the stack printing code in
// VMError::report:
// - Step 110 (printing stack bounds) uses the sp in the frame
// to determine the amount of free space on the stack. We
// set the sp to a close approximation of the real value in
// order to allow this step to complete.
// - Step 120 (printing native stack) tries to walk the stack.
// The frame we create has a NULL pc, which is ignored as an
// invalid frame.
frame dummy = frame();
dummy.set_sp((intptr_t *) current_stack_pointer());
return dummy;
}
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).
#ifdef SPARC
// On SPARC, 0 != %hi(any real address), because there is no
// allocation in the first 1Kb of the virtual address space.
return (char *) 0;
#else
// This is the value for x86; works pretty well for PPC too.
return (char *) -1;
#endif // SPARC
}
address os::Linux::ucontext_get_pc(const ucontext_t* uc) {
ShouldNotCallThis();
return NULL; // silence compile warnings
}
void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
ShouldNotCallThis();
}
ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
intptr_t** ret_sp,
intptr_t** ret_fp) {
ShouldNotCallThis();
return NULL; // silence compile warnings
}
frame os::fetch_frame_from_context(const void* ucVoid) {
ShouldNotCallThis();
return frame(NULL, NULL); // silence compile warnings
}
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);
// handle SafeFetch faults
if (sig == SIGSEGV || sig == SIGBUS) {
sigjmp_buf* const pjb = get_jmp_buf_for_continuation();
if (pjb) {
siglongjmp(*pjb, 1);
}
}
// 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;
}
}
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;
}
}
}
if (info != NULL && thread != NULL) {
// Handle ALL stack overflow variations here
if (sig == SIGSEGV) {
address addr = (address) info->si_addr;
// check if fault address is within thread stack
if (thread->on_local_stack(addr)) {
// stack overflow
if (thread->in_stack_yellow_reserved_zone(addr)) {
thread->disable_stack_yellow_reserved_zone();
ShouldNotCallThis();
}
else if (thread->in_stack_red_zone(addr)) {
thread->disable_stack_red_zone();
ShouldNotCallThis();
}
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 true;
}
thread->osthread()->clear_expanding_stack();
}
else {
fatal("recursive segv. expanding stack.");
}
}
}
}
/*if (thread->thread_state() == _thread_in_Java) {
ShouldNotCallThis();
}
else*/ if (thread->thread_state() == _thread_in_vm &&
sig == SIGBUS && thread->doing_unsafe_access()) {
ShouldNotCallThis();
}
// 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;
}
}*/
}
// 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;
}
#ifndef PRODUCT
if (sig == SIGSEGV) {
fatal("\n#"
"\n# /--------------------\\"
"\n# | segmentation fault |"
"\n# \\---\\ /--------------/"
"\n# /"
"\n# [-] |\\_/| "
"\n# (+)=C |o o|__ "
"\n# | | =-*-=__\\ "
"\n# OOO c_c_(___)");
}
#endif // !PRODUCT
char buf[64];
sprintf(buf, "caught unhandled signal %d", sig);
// Silence -Wformat-security warning for fatal()
PRAGMA_DIAG_PUSH
PRAGMA_FORMAT_NONLITERAL_IGNORED
fatal(buf);
PRAGMA_DIAG_POP
return true; // silence compiler warnings
}
void os::Linux::init_thread_fpu_state(void) {
// Nothing to do
}
int os::Linux::get_fpu_control_word() {
ShouldNotCallThis();
return -1; // silence compile warnings
}
void os::Linux::set_fpu_control_word(int fpu) {
ShouldNotCallThis();
}
bool os::is_allocatable(size_t bytes) {
#ifdef _LP64
return true;
#else
if (bytes < 2 * G) {
return true;
}
char* addr = reserve_memory(bytes, NULL);
if (addr != NULL) {
release_memory(addr, bytes);
}
return addr != NULL;
#endif // _LP64
}
///////////////////////////////////////////////////////////////////////////////
// thread stack
size_t os::Posix::_compiler_thread_min_stack_allowed = 64 * K;
size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
#ifdef _LP64
size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
#else
size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
#endif // _LP64
return s;
}
static void current_stack_region(address *bottom, size_t *size) {
pthread_attr_t attr;
int res = pthread_getattr_np(pthread_self(), &attr);
if (res != 0) {
if (res == ENOMEM) {
vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
}
else {
fatal("pthread_getattr_np failed with error = %d", res);
}
}
address stack_bottom;
size_t stack_bytes;
res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes);
if (res != 0) {
fatal("pthread_attr_getstack failed with error = %d", res);
}
address stack_top = stack_bottom + stack_bytes;
// The block of memory returned by pthread_attr_getstack() includes
// guard pages where present. We need to trim these off.
size_t page_bytes = os::Linux::page_size();
assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack");
size_t guard_bytes;
res = pthread_attr_getguardsize(&attr, &guard_bytes);
if (res != 0) {
fatal("pthread_attr_getguardsize failed with errno = %d", res);
}
int guard_pages = align_up(guard_bytes, page_bytes) / page_bytes;
assert(guard_bytes == guard_pages * page_bytes, "unaligned guard");
#ifdef IA64
// IA64 has two stacks sharing the same area of memory, a normal
// stack growing downwards and a register stack growing upwards.
// Guard pages, if present, are in the centre. This code splits
// the stack in two even without guard pages, though in theory
// there's nothing to stop us allocating more to the normal stack
// or more to the register stack if one or the other were found
// to grow faster.
int total_pages = align_down(stack_bytes, page_bytes) / page_bytes;
stack_bottom += (total_pages - guard_pages) / 2 * page_bytes;
#endif // IA64
stack_bottom += guard_bytes;
pthread_attr_destroy(&attr);
// The initial thread has a growable stack, and the size reported
// by pthread_attr_getstack is the maximum size it could possibly
// be given what currently mapped. This can be huge, so we cap it.
if (os::is_primordial_thread()) {
stack_bytes = stack_top - stack_bottom;
if (stack_bytes > JavaThread::stack_size_at_create())
stack_bytes = JavaThread::stack_size_at_create();
stack_bottom = stack_top - stack_bytes;
}
assert(os::current_stack_pointer() >= stack_bottom, "should do");
assert(os::current_stack_pointer() < stack_top, "should do");
*bottom = stack_bottom;
*size = stack_top - stack_bottom;
}
address os::current_stack_base() {
address bottom;
size_t size;
current_stack_region(&bottom, &size);
return bottom + size;
}
size_t os::current_stack_size() {
// stack size includes normal stack and HotSpot guard pages
address bottom;
size_t size;
current_stack_region(&bottom, &size);
return size;
}
/////////////////////////////////////////////////////////////////////////////
// helper functions for fatal error handler
void os::print_context(outputStream* st, const void* context) {
ShouldNotCallThis();
}
void os::print_register_info(outputStream *st, const void *context) {
ShouldNotCallThis();
}
/////////////////////////////////////////////////////////////////////////////
// Stubs for things that would be in linux_zero.s if it existed.
// You probably want to disassemble these monkeys to check they're ok.
extern "C" {
int SpinPause() {
return -1; // silence compile warnings
}
void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) {
if (from > to) {
jshort *end = from + count;
while (from < end)
*(to++) = *(from++);
}
else if (from < to) {
jshort *end = from;
from += count - 1;
to += count - 1;
while (from >= end)
*(to--) = *(from--);
}
}
void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) {
if (from > to) {
jint *end = from + count;
while (from < end)
*(to++) = *(from++);
}
else if (from < to) {
jint *end = from;
from += count - 1;
to += count - 1;
while (from >= end)
*(to--) = *(from--);
}
}
void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) {
if (from > to) {
jlong *end = from + count;
while (from < end)
os::atomic_copy64(from++, to++);
}
else if (from < to) {
jlong *end = from;
from += count - 1;
to += count - 1;
while (from >= end)
os::atomic_copy64(from--, to--);
}
}
void _Copy_arrayof_conjoint_bytes(HeapWord* from,
HeapWord* to,
size_t count) {
memmove(to, from, count);
}
void _Copy_arrayof_conjoint_jshorts(HeapWord* from,
HeapWord* to,
size_t count) {
memmove(to, from, count * 2);
}
void _Copy_arrayof_conjoint_jints(HeapWord* from,
HeapWord* to,
size_t count) {
memmove(to, from, count * 4);
}
void _Copy_arrayof_conjoint_jlongs(HeapWord* from,
HeapWord* to,
size_t count) {
memmove(to, from, count * 8);
}
};
/////////////////////////////////////////////////////////////////////////////
// Implementations of atomic operations not supported by processors.
// -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html
#ifndef _LP64
extern "C" {
long long unsigned int __sync_val_compare_and_swap_8(
volatile void *ptr,
long long unsigned int oldval,
long long unsigned int newval) {
ShouldNotCallThis();
}
};
#endif // !_LP64
#ifndef PRODUCT
void os::verify_stack_alignment() {
}
#endif
int os::extra_bang_size_in_bytes() {
// Zero does not require an additional stack banging.
return 0;
}