Java example source code file (os_linux_x86.cpp)
The os_linux_x86.cpp Java example source code
/*
* Copyright (c) 1999, 2013, 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 "asm/macroAssembler.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 "jvm_linux.h"
#include "memory/allocation.inline.hpp"
#include "mutex_linux.inline.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 <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>
#ifdef AMD64
#define REG_SP REG_RSP
#define REG_PC REG_RIP
#define REG_FP REG_RBP
#define SPELL_REG_SP "rsp"
#define SPELL_REG_FP "rbp"
#else
#define REG_SP REG_UESP
#define REG_PC REG_EIP
#define REG_FP REG_EBP
#define SPELL_REG_SP "esp"
#define SPELL_REG_FP "ebp"
#endif // AMD64
address os::current_stack_pointer() {
#ifdef SPARC_WORKS
register void *esp;
__asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
return (address) ((char*)esp + sizeof(long)*2);
#elif defined(__clang__)
intptr_t* esp;
__asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):);
return (address) esp;
#else
register void *esp __asm__ (SPELL_REG_SP);
return (address) esp;
#endif
}
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* thr) {
// Nothing to do.
}
address os::Linux::ucontext_get_pc(ucontext_t * uc) {
return (address)uc->uc_mcontext.gregs[REG_PC];
}
intptr_t* os::Linux::ucontext_get_sp(ucontext_t * uc) {
return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
}
intptr_t* os::Linux::ucontext_get_fp(ucontext_t * uc) {
return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
}
// 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,
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(void* ucVoid,
intptr_t** ret_sp, intptr_t** ret_fp) {
ExtendedPC epc;
ucontext_t* uc = (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(void* ucVoid) {
intptr_t* sp;
intptr_t* fp;
ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
return frame(sp, fp, epc.pc());
}
// By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
// turned off by -fomit-frame-pointer,
frame os::get_sender_for_C_frame(frame* fr) {
return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
}
intptr_t* _get_previous_fp() {
#ifdef SPARC_WORKS
register intptr_t **ebp;
__asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
#elif defined(__clang__)
intptr_t **ebp;
__asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):);
#else
register intptr_t **ebp __asm__ (SPELL_REG_FP);
#endif
return (intptr_t*) *ebp; // we want what it points to.
}
frame os::current_frame() {
intptr_t* fp = _get_previous_fp();
frame myframe((intptr_t*)os::current_stack_pointer(),
(intptr_t*)fp,
CAST_FROM_FN_PTR(address, os::current_frame));
if (os::is_first_C_frame(&myframe)) {
// stack is not walkable
return frame();
} else {
return os::get_sender_for_C_frame(&myframe);
}
}
// Utility functions
// From IA32 System Programming Guide
enum {
trap_page_fault = 0xE
};
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 = ThreadLocalStorage::get_thread_slow();
// Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
// (no destructors can be run)
os::WatcherThreadCrashProtection::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 || sig == SIGXFSZ) {
// allow chained handler to go first
if (os::Linux::chained_handler(sig, info, ucVoid)) {
return true;
} else {
if (PrintMiscellaneous && (WizardMode || Verbose)) {
char buf[64];
warning("Ignoring %s - see bugs 4229104 or 646499219",
os::exception_name(sig, buf, sizeof(buf)));
}
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;
}
}
}
/*
NOTE: does not seem to work on linux.
if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
// can't decode this kind of signal
info = NULL;
} else {
assert(sig == info->si_signo, "bad siginfo");
}
*/
// 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);
if (StubRoutines::is_safefetch_fault(pc)) {
uc->uc_mcontext.gregs[REG_PC] = intptr_t(StubRoutines::continuation_for_safefetch_fault(pc));
return 1;
}
#ifndef AMD64
// Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs
// This can happen in any running code (currently more frequently in
// interpreter code but has been seen in compiled code)
if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) {
fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due "
"to unstable signal handling in this distribution.");
}
#endif // AMD64
// Handle ALL stack overflow variations here
if (sig == SIGSEGV) {
address addr = (address) info->si_addr;
// 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_zone(addr)) {
thread->disable_stack_yellow_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.");
// 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
if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
stub = SharedRuntime::get_poll_stub(pc);
} else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
// 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);
nmethod* nm = (cb != NULL && cb->is_nmethod()) ? (nmethod*)cb : NULL;
if (nm != NULL && nm->has_unsafe_access()) {
stub = StubRoutines::handler_for_unsafe_access();
}
}
else
#ifdef AMD64
if (sig == SIGFPE &&
(info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
stub =
SharedRuntime::
continuation_for_implicit_exception(thread,
pc,
SharedRuntime::
IMPLICIT_DIVIDE_BY_ZERO);
#else
if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
// HACK: si_code does not work on linux 2.2.12-20!!!
int op = pc[0];
if (op == 0xDB) {
// FIST
// TODO: The encoding of D2I in i486.ad can cause an exception
// prior to the fist instruction if there was an invalid operation
// pending. We want to dismiss that exception. From the win_32
// side it also seems that if it really was the fist causing
// the exception that we do the d2i by hand with different
// rounding. Seems kind of weird.
// NOTE: that we take the exception at the NEXT floating point instruction.
assert(pc[0] == 0xDB, "not a FIST opcode");
assert(pc[1] == 0x14, "not a FIST opcode");
assert(pc[2] == 0x24, "not a FIST opcode");
return true;
} else if (op == 0xF7) {
// IDIV
stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
} else {
// TODO: handle more cases if we are using other x86 instructions
// that can generate SIGFPE signal on linux.
tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
fatal("please update this code.");
}
#endif // AMD64
} else if (sig == SIGSEGV &&
!MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
// Determination of interpreter/vtable stub/compiled code null exception
stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
}
} else if (thread->thread_state() == _thread_in_vm &&
sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
thread->doing_unsafe_access()) {
stub = StubRoutines::handler_for_unsafe_access();
}
// 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;
}
}
// 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) &&
os::is_memory_serialize_page(thread, (address) info->si_addr)) {
// Block current thread until the memory serialize page permission restored.
os::block_on_serialize_page_trap();
return true;
}
}
#ifndef AMD64
// Execution protection violation
//
// This should be kept as the last step in the triage. We don't
// have a dedicated trap number for a no-execute fault, so be
// conservative and allow other handlers the first shot.
//
// Note: We don't test that info->si_code == SEGV_ACCERR here.
// this si_code is so generic that it is almost meaningless; and
// the si_code for this condition may change in the future.
// Furthermore, a false-positive should be harmless.
if (UnguardOnExecutionViolation > 0 &&
(sig == SIGSEGV || sig == SIGBUS) &&
uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
int page_size = os::vm_page_size();
address addr = (address) info->si_addr;
address pc = os::Linux::ucontext_get_pc(uc);
// Make sure the pc and the faulting address are sane.
//
// If an instruction spans a page boundary, and the page containing
// the beginning of the instruction is executable but the following
// page is not, the pc and the faulting address might be slightly
// different - we still want to unguard the 2nd page in this case.
//
// 15 bytes seems to be a (very) safe value for max instruction size.
bool pc_is_near_addr =
(pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
bool instr_spans_page_boundary =
(align_size_down((intptr_t) pc ^ (intptr_t) addr,
(intptr_t) page_size) > 0);
if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
static volatile address last_addr =
(address) os::non_memory_address_word();
// In conservative mode, don't unguard unless the address is in the VM
if (addr != last_addr &&
(UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
// Set memory to RWX and retry
address page_start =
(address) align_size_down((intptr_t) addr, (intptr_t) page_size);
bool res = os::protect_memory((char*) page_start, page_size,
os::MEM_PROT_RWX);
if (PrintMiscellaneous && Verbose) {
char buf[256];
jio_snprintf(buf, sizeof(buf), "Execution protection violation "
"at " INTPTR_FORMAT
", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,
page_start, (res ? "success" : "failed"), errno);
tty->print_raw_cr(buf);
}
stub = pc;
// Set last_addr so if we fault again at the same address, we don't end
// up in an endless loop.
//
// There are two potential complications here. Two threads trapping at
// the same address at the same time could cause one of the threads to
// think it already unguarded, and abort the VM. Likely very rare.
//
// The other race involves two threads alternately trapping at
// different addresses and failing to unguard the page, resulting in
// an endless loop. This condition is probably even more unlikely than
// the first.
//
// Although both cases could be avoided by using locks or thread local
// last_addr, these solutions are unnecessary complication: this
// handler is a best-effort safety net, not a complete solution. It is
// disabled by default and should only be used as a workaround in case
// we missed any no-execute-unsafe VM code.
last_addr = addr;
}
}
}
#endif // !AMD64
if (stub != NULL) {
// save all thread context in case we need to restore it
if (thread != NULL) thread->set_saved_exception_pc(pc);
uc->uc_mcontext.gregs[REG_PC] = (greg_t)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 err(t, sig, pc, info, ucVoid);
err.report_and_die();
ShouldNotReachHere();
}
void os::Linux::init_thread_fpu_state(void) {
#ifndef AMD64
// set fpu to 53 bit precision
set_fpu_control_word(0x27f);
#endif // !AMD64
}
int os::Linux::get_fpu_control_word(void) {
#ifdef AMD64
return 0;
#else
int fpu_control;
_FPU_GETCW(fpu_control);
return fpu_control & 0xffff;
#endif // AMD64
}
void os::Linux::set_fpu_control_word(int fpu_control) {
#ifndef AMD64
_FPU_SETCW(fpu_control);
#endif // !AMD64
}
// Check that the linux kernel version is 2.4 or higher since earlier
// versions do not support SSE without patches.
bool os::supports_sse() {
#ifdef AMD64
return true;
#else
struct utsname uts;
if( uname(&uts) != 0 ) return false; // uname fails?
char *minor_string;
int major = strtol(uts.release,&minor_string,10);
int minor = strtol(minor_string+1,NULL,10);
bool result = (major > 2 || (major==2 && minor >= 4));
#ifndef PRODUCT
if (PrintMiscellaneous && Verbose) {
tty->print("OS version is %d.%d, which %s support SSE/SSE2\n",
major,minor, result ? "DOES" : "does NOT");
}
#endif
return result;
#endif // AMD64
}
bool os::is_allocatable(size_t bytes) {
#ifdef AMD64
// unused on amd64?
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 // AMD64
}
////////////////////////////////////////////////////////////////////////////////
// thread stack
#ifdef AMD64
size_t os::Linux::min_stack_allowed = 64 * K;
// amd64: pthread on amd64 is always in floating stack mode
bool os::Linux::supports_variable_stack_size() { return true; }
#else
size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K;
#ifdef __GNUC__
#define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})
#endif
// Test if pthread library can support variable thread stack size. LinuxThreads
// in fixed stack mode allocates 2M fixed slot for each thread. LinuxThreads
// in floating stack mode and NPTL support variable stack size.
bool os::Linux::supports_variable_stack_size() {
if (os::Linux::is_NPTL()) {
// NPTL, yes
return true;
} else {
// Note: We can't control default stack size when creating a thread.
// If we use non-default stack size (pthread_attr_setstacksize), both
// floating stack and non-floating stack LinuxThreads will return the
// same value. This makes it impossible to implement this function by
// detecting thread stack size directly.
//
// An alternative approach is to check %gs. Fixed-stack LinuxThreads
// do not use %gs, so its value is 0. Floating-stack LinuxThreads use
// %gs (either as LDT selector or GDT selector, depending on kernel)
// to access thread specific data.
//
// Note that %gs is a reserved glibc register since early 2001, so
// applications are not allowed to change its value (Ulrich Drepper from
// Redhat confirmed that all known offenders have been modified to use
// either %fs or TSD). In the worst case scenario, when VM is embedded in
// a native application that plays with %gs, we might see non-zero %gs
// even LinuxThreads is running in fixed stack mode. As the result, we'll
// return true and skip _thread_safety_check(), so we may not be able to
// detect stack-heap collisions. But otherwise it's harmless.
//
#ifdef __GNUC__
return (GET_GS() != 0);
#else
return false;
#endif
}
}
#endif // AMD64
// return default stack size for thr_type
size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
// default stack size (compiler thread needs larger stack)
#ifdef AMD64
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 // AMD64
return s;
}
size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
// Creating guard page is very expensive. Java thread has HotSpot
// guard page, only enable glibc guard page for non-Java threads.
return (thr_type == java_thread ? 0 : page_size());
}
// Java thread:
//
// Low memory addresses
// +------------------------+
// | |\ JavaThread created by VM does not have glibc
// | glibc guard page | - guard, attached Java thread usually has
// | |/ 1 page glibc guard.
// P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
// | |\
// | HotSpot Guard Pages | - red and yellow pages
// | |/
// +------------------------+ JavaThread::stack_yellow_zone_base()
// | |\
// | Normal Stack | -
// | |/
// P2 +------------------------+ Thread::stack_base()
//
// Non-Java thread:
//
// Low memory addresses
// +------------------------+
// | |\
// | glibc guard page | - usually 1 page
// | |/
// P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
// | |\
// | Normal Stack | -
// | |/
// P2 +------------------------+ Thread::stack_base()
//
// ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
// pthread_attr_getstack()
static void current_stack_region(address * bottom, size_t * size) {
if (os::Linux::is_initial_thread()) {
// initial thread needs special handling because pthread_getattr_np()
// may return bogus value.
*bottom = os::Linux::initial_thread_stack_bottom();
*size = os::Linux::initial_thread_stack_size();
} else {
pthread_attr_t attr;
int rslt = pthread_getattr_np(pthread_self(), &attr);
// JVM needs to know exact stack location, abort if it fails
if (rslt != 0) {
if (rslt == ENOMEM) {
vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
} else {
fatal(err_msg("pthread_getattr_np failed with errno = %d", rslt));
}
}
if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
fatal("Can not locate current stack attributes!");
}
pthread_attr_destroy(&attr);
}
assert(os::current_stack_pointer() >= *bottom &&
os::current_stack_pointer() < *bottom + *size, "just checking");
}
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, void *context) {
if (context == NULL) return;
ucontext_t *uc = (ucontext_t*)context;
st->print_cr("Registers:");
#ifdef AMD64
st->print( "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
st->cr();
st->print( "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
st->cr();
st->print( "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
st->cr();
st->print( "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
st->cr();
st->print( "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
st->print(", CSGSFS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_CSGSFS]);
st->print(", ERR=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ERR]);
st->cr();
st->print(" TRAPNO=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_TRAPNO]);
#else
st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
st->cr();
st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
st->cr();
st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
st->print(", CR2=" INTPTR_FORMAT, uc->uc_mcontext.cr2);
#endif // AMD64
st->cr();
st->cr();
intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", 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);
st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
}
void os::print_register_info(outputStream *st, void *context) {
if (context == NULL) return;
ucontext_t *uc = (ucontext_t*)context;
st->print_cr("Register to memory mapping:");
st->cr();
// this is horrendously verbose but the layout of the registers in the
// context does not match how we defined our abstract Register set, so
// we can't just iterate through the gregs area
// this is only for the "general purpose" registers
#ifdef AMD64
st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
#else
st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
#endif // AMD64
st->cr();
}
void os::setup_fpu() {
#ifndef AMD64
address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
__asm__ volatile ( "fldcw (%0)" :
: "r" (fpu_cntrl) : "memory");
#endif // !AMD64
}
#ifndef PRODUCT
void os::verify_stack_alignment() {
#ifdef AMD64
assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
#endif
}
#endif
/*
* IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit
* updates (JDK-8023956).
*/
void os::workaround_expand_exec_shield_cs_limit() {
#if defined(IA32)
size_t page_size = os::vm_page_size();
/*
* Take the highest VA the OS will give us and exec
*
* Although using -(pagesz) as mmap hint works on newer kernel as you would
* think, older variants affected by this work-around don't (search forward only).
*
* On the affected distributions, we understand the memory layout to be:
*
* TASK_LIMIT= 3G, main stack base close to TASK_LIMT.
*
* A few pages south main stack will do it.
*
* If we are embedded in an app other than launcher (initial != main stack),
* we don't have much control or understanding of the address space, just let it slide.
*/
char* hint = (char*) (Linux::initial_thread_stack_bottom() -
((StackYellowPages + StackRedPages + 1) * page_size));
char* codebuf = os::reserve_memory(page_size, hint);
if ( (codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true)) ) {
return; // No matter, we tried, best effort.
}
if (PrintMiscellaneous && (Verbose || WizardMode)) {
tty->print_cr("[CS limit NX emulation work-around, exec code at: %p]", codebuf);
}
// Some code to exec: the 'ret' instruction
codebuf[0] = 0xC3;
// Call the code in the codebuf
__asm__ volatile("call *%0" : : "r"(codebuf));
// keep the page mapped so CS limit isn't reduced.
#endif
}
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