Java example source code file (os_bsd_x86.cpp)
The os_bsd_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_bsd.h"
#include "memory/allocation.inline.hpp"
#include "mutex_bsd.inline.hpp"
#include "os_share_bsd.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>
#ifndef __OpenBSD__
# include <ucontext.h>
#endif
#if !defined(__APPLE__) && !defined(__NetBSD__)
# include <pthread_np.h>
#endif
// needed by current_stack_region() workaround for Mavericks
#if defined(__APPLE__)
# include <errno.h>
# include <sys/types.h>
# include <sys/sysctl.h>
# define DEFAULT_MAIN_THREAD_STACK_PAGES 2048
# define OS_X_10_9_0_KERNEL_MAJOR_VERSION 13
#endif
#ifdef AMD64
#define SPELL_REG_SP "rsp"
#define SPELL_REG_FP "rbp"
#else
#define SPELL_REG_SP "esp"
#define SPELL_REG_FP "ebp"
#endif // AMD64
#ifdef __FreeBSD__
# define context_trapno uc_mcontext.mc_trapno
# ifdef AMD64
# define context_pc uc_mcontext.mc_rip
# define context_sp uc_mcontext.mc_rsp
# define context_fp uc_mcontext.mc_rbp
# define context_rip uc_mcontext.mc_rip
# define context_rsp uc_mcontext.mc_rsp
# define context_rbp uc_mcontext.mc_rbp
# define context_rax uc_mcontext.mc_rax
# define context_rbx uc_mcontext.mc_rbx
# define context_rcx uc_mcontext.mc_rcx
# define context_rdx uc_mcontext.mc_rdx
# define context_rsi uc_mcontext.mc_rsi
# define context_rdi uc_mcontext.mc_rdi
# define context_r8 uc_mcontext.mc_r8
# define context_r9 uc_mcontext.mc_r9
# define context_r10 uc_mcontext.mc_r10
# define context_r11 uc_mcontext.mc_r11
# define context_r12 uc_mcontext.mc_r12
# define context_r13 uc_mcontext.mc_r13
# define context_r14 uc_mcontext.mc_r14
# define context_r15 uc_mcontext.mc_r15
# define context_flags uc_mcontext.mc_flags
# define context_err uc_mcontext.mc_err
# else
# define context_pc uc_mcontext.mc_eip
# define context_sp uc_mcontext.mc_esp
# define context_fp uc_mcontext.mc_ebp
# define context_eip uc_mcontext.mc_eip
# define context_esp uc_mcontext.mc_esp
# define context_eax uc_mcontext.mc_eax
# define context_ebx uc_mcontext.mc_ebx
# define context_ecx uc_mcontext.mc_ecx
# define context_edx uc_mcontext.mc_edx
# define context_ebp uc_mcontext.mc_ebp
# define context_esi uc_mcontext.mc_esi
# define context_edi uc_mcontext.mc_edi
# define context_eflags uc_mcontext.mc_eflags
# define context_trapno uc_mcontext.mc_trapno
# endif
#endif
#ifdef __APPLE__
# if __DARWIN_UNIX03 && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5)
// 10.5 UNIX03 member name prefixes
#define DU3_PREFIX(s, m) __ ## s.__ ## m
# else
#define DU3_PREFIX(s, m) s ## . ## m
# endif
# ifdef AMD64
# define context_pc context_rip
# define context_sp context_rsp
# define context_fp context_rbp
# define context_rip uc_mcontext->DU3_PREFIX(ss,rip)
# define context_rsp uc_mcontext->DU3_PREFIX(ss,rsp)
# define context_rax uc_mcontext->DU3_PREFIX(ss,rax)
# define context_rbx uc_mcontext->DU3_PREFIX(ss,rbx)
# define context_rcx uc_mcontext->DU3_PREFIX(ss,rcx)
# define context_rdx uc_mcontext->DU3_PREFIX(ss,rdx)
# define context_rbp uc_mcontext->DU3_PREFIX(ss,rbp)
# define context_rsi uc_mcontext->DU3_PREFIX(ss,rsi)
# define context_rdi uc_mcontext->DU3_PREFIX(ss,rdi)
# define context_r8 uc_mcontext->DU3_PREFIX(ss,r8)
# define context_r9 uc_mcontext->DU3_PREFIX(ss,r9)
# define context_r10 uc_mcontext->DU3_PREFIX(ss,r10)
# define context_r11 uc_mcontext->DU3_PREFIX(ss,r11)
# define context_r12 uc_mcontext->DU3_PREFIX(ss,r12)
# define context_r13 uc_mcontext->DU3_PREFIX(ss,r13)
# define context_r14 uc_mcontext->DU3_PREFIX(ss,r14)
# define context_r15 uc_mcontext->DU3_PREFIX(ss,r15)
# define context_flags uc_mcontext->DU3_PREFIX(ss,rflags)
# define context_trapno uc_mcontext->DU3_PREFIX(es,trapno)
# define context_err uc_mcontext->DU3_PREFIX(es,err)
# else
# define context_pc context_eip
# define context_sp context_esp
# define context_fp context_ebp
# define context_eip uc_mcontext->DU3_PREFIX(ss,eip)
# define context_esp uc_mcontext->DU3_PREFIX(ss,esp)
# define context_eax uc_mcontext->DU3_PREFIX(ss,eax)
# define context_ebx uc_mcontext->DU3_PREFIX(ss,ebx)
# define context_ecx uc_mcontext->DU3_PREFIX(ss,ecx)
# define context_edx uc_mcontext->DU3_PREFIX(ss,edx)
# define context_ebp uc_mcontext->DU3_PREFIX(ss,ebp)
# define context_esi uc_mcontext->DU3_PREFIX(ss,esi)
# define context_edi uc_mcontext->DU3_PREFIX(ss,edi)
# define context_eflags uc_mcontext->DU3_PREFIX(ss,eflags)
# define context_trapno uc_mcontext->DU3_PREFIX(es,trapno)
# endif
#endif
#ifdef __OpenBSD__
# define context_trapno sc_trapno
# ifdef AMD64
# define context_pc sc_rip
# define context_sp sc_rsp
# define context_fp sc_rbp
# define context_rip sc_rip
# define context_rsp sc_rsp
# define context_rbp sc_rbp
# define context_rax sc_rax
# define context_rbx sc_rbx
# define context_rcx sc_rcx
# define context_rdx sc_rdx
# define context_rsi sc_rsi
# define context_rdi sc_rdi
# define context_r8 sc_r8
# define context_r9 sc_r9
# define context_r10 sc_r10
# define context_r11 sc_r11
# define context_r12 sc_r12
# define context_r13 sc_r13
# define context_r14 sc_r14
# define context_r15 sc_r15
# define context_flags sc_rflags
# define context_err sc_err
# else
# define context_pc sc_eip
# define context_sp sc_esp
# define context_fp sc_ebp
# define context_eip sc_eip
# define context_esp sc_esp
# define context_eax sc_eax
# define context_ebx sc_ebx
# define context_ecx sc_ecx
# define context_edx sc_edx
# define context_ebp sc_ebp
# define context_esi sc_esi
# define context_edi sc_edi
# define context_eflags sc_eflags
# define context_trapno sc_trapno
# endif
#endif
#ifdef __NetBSD__
# define context_trapno uc_mcontext.__gregs[_REG_TRAPNO]
# ifdef AMD64
# define __register_t __greg_t
# define context_pc uc_mcontext.__gregs[_REG_RIP]
# define context_sp uc_mcontext.__gregs[_REG_URSP]
# define context_fp uc_mcontext.__gregs[_REG_RBP]
# define context_rip uc_mcontext.__gregs[_REG_RIP]
# define context_rsp uc_mcontext.__gregs[_REG_URSP]
# define context_rax uc_mcontext.__gregs[_REG_RAX]
# define context_rbx uc_mcontext.__gregs[_REG_RBX]
# define context_rcx uc_mcontext.__gregs[_REG_RCX]
# define context_rdx uc_mcontext.__gregs[_REG_RDX]
# define context_rbp uc_mcontext.__gregs[_REG_RBP]
# define context_rsi uc_mcontext.__gregs[_REG_RSI]
# define context_rdi uc_mcontext.__gregs[_REG_RDI]
# define context_r8 uc_mcontext.__gregs[_REG_R8]
# define context_r9 uc_mcontext.__gregs[_REG_R9]
# define context_r10 uc_mcontext.__gregs[_REG_R10]
# define context_r11 uc_mcontext.__gregs[_REG_R11]
# define context_r12 uc_mcontext.__gregs[_REG_R12]
# define context_r13 uc_mcontext.__gregs[_REG_R13]
# define context_r14 uc_mcontext.__gregs[_REG_R14]
# define context_r15 uc_mcontext.__gregs[_REG_R15]
# define context_flags uc_mcontext.__gregs[_REG_RFL]
# define context_err uc_mcontext.__gregs[_REG_ERR]
# else
# define context_pc uc_mcontext.__gregs[_REG_EIP]
# define context_sp uc_mcontext.__gregs[_REG_UESP]
# define context_fp uc_mcontext.__gregs[_REG_EBP]
# define context_eip uc_mcontext.__gregs[_REG_EIP]
# define context_esp uc_mcontext.__gregs[_REG_UESP]
# define context_eax uc_mcontext.__gregs[_REG_EAX]
# define context_ebx uc_mcontext.__gregs[_REG_EBX]
# define context_ecx uc_mcontext.__gregs[_REG_ECX]
# define context_edx uc_mcontext.__gregs[_REG_EDX]
# define context_ebp uc_mcontext.__gregs[_REG_EBP]
# define context_esi uc_mcontext.__gregs[_REG_ESI]
# define context_edi uc_mcontext.__gregs[_REG_EDI]
# define context_eflags uc_mcontext.__gregs[_REG_EFL]
# define context_trapno uc_mcontext.__gregs[_REG_TRAPNO]
# endif
#endif
address os::current_stack_pointer() {
#if defined(__clang__) || defined(__llvm__)
register void *esp;
__asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
return (address) esp;
#elif defined(SPARC_WORKS)
register void *esp;
__asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
return (address) ((char*)esp + sizeof(long)*2);
#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::Bsd::ucontext_get_pc(ucontext_t * uc) {
return (address)uc->context_pc;
}
intptr_t* os::Bsd::ucontext_get_sp(ucontext_t * uc) {
return (intptr_t*)uc->context_sp;
}
intptr_t* os::Bsd::ucontext_get_fp(ucontext_t * uc) {
return (intptr_t*)uc->context_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 Bsd, so it's the same as
// os::fetch_frame_from_context().
ExtendedPC os::Bsd::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::Bsd::ucontext_get_pc(uc));
if (ret_sp) *ret_sp = os::Bsd::ucontext_get_sp(uc);
if (ret_fp) *ret_fp = os::Bsd::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() {
#if defined(SPARC_WORKS) || defined(__clang__) || defined(__llvm__)
register intptr_t **ebp;
__asm__("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_bsd_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_bsd_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::Bsd::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::Bsd::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 bsd.
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::Bsd::ucontext_get_pc(uc);
if (StubRoutines::is_safefetch_fault(pc)) {
uc->context_pc = intptr_t(StubRoutines::continuation_for_safefetch_fault(pc));
return 1;
}
// Handle ALL stack overflow variations here
if (sig == SIGSEGV || sig == SIGBUS) {
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.");
}
}
}
// We test if stub is already set (by the stack overflow code
// above) so it is not overwritten by the code that follows. This
// check is not required on other platforms, because on other
// platforms we check for SIGSEGV only or SIGBUS only, where here
// we have to check for both SIGSEGV and SIGBUS.
if (thread->thread_state() == _thread_in_Java && stub == NULL) {
// Java thread running in Java code => find exception handler if any
// a fault inside compiled code, the interpreter, or a stub
if ((sig == SIGSEGV || sig == SIGBUS) && os::is_poll_address((address)info->si_addr)) {
stub = SharedRuntime::get_poll_stub(pc);
#if defined(__APPLE__)
// 32-bit Darwin reports a SIGBUS for nearly all memory access exceptions.
// 64-bit Darwin may also use a SIGBUS (seen with compressed oops).
// Catching SIGBUS here prevents the implicit SIGBUS NULL check below from
// being called, so only do so if the implicit NULL check is not necessary.
} else if (sig == SIGBUS && MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
#else
} else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
#endif
// 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);
#ifdef __APPLE__
} else if (sig == SIGFPE && info->si_code == FPE_NOOP) {
int op = pc[0];
// Skip REX
if ((pc[0] & 0xf0) == 0x40) {
op = pc[1];
} else {
op = pc[0];
}
// Check for IDIV
if (op == 0xF7) {
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.
tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
fatal("please update this code.");
}
#endif /* __APPLE__ */
#else
if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
// HACK: si_code does not work on bsd 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 bsd.
tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
fatal("please update this code.");
}
#endif // AMD64
} else if ((sig == SIGSEGV || sig == SIGBUS) &&
!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 || sig == SIGBUS) &&
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->context_trapno == trap_page_fault) {
int page_size = os::vm_page_size();
address addr = (address) info->si_addr;
address pc = os::Bsd::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->context_pc = (intptr_t)stub;
return true;
}
// signal-chaining
if (os::Bsd::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::Bsd::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();
return false;
}
// From solaris_i486.s ported to bsd_i486.s
extern "C" void fixcw();
void os::Bsd::init_thread_fpu_state(void) {
#ifndef AMD64
// Set fpu to 53 bit precision. This happens too early to use a stub.
fixcw();
#endif // !AMD64
}
// Check that the bsd kernel version is 2.4 or higher since earlier
// versions do not support SSE without patches.
bool os::supports_sse() {
return true;
}
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::Bsd::min_stack_allowed = 64 * K;
// amd64: pthread on amd64 is always in floating stack mode
bool os::Bsd::supports_variable_stack_size() { return true; }
#else
size_t os::Bsd::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
bool os::Bsd::supports_variable_stack_size() { return true; }
#endif // AMD64
// return default stack size for thr_type
size_t os::Bsd::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::Bsd::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) {
#ifdef __APPLE__
pthread_t self = pthread_self();
void *stacktop = pthread_get_stackaddr_np(self);
*size = pthread_get_stacksize_np(self);
// workaround for OS X 10.9.0 (Mavericks)
// pthread_get_stacksize_np returns 128 pages even though the actual size is 2048 pages
if (pthread_main_np() == 1) {
if ((*size) < (DEFAULT_MAIN_THREAD_STACK_PAGES * (size_t)getpagesize())) {
char kern_osrelease[256];
size_t kern_osrelease_size = sizeof(kern_osrelease);
int ret = sysctlbyname("kern.osrelease", kern_osrelease, &kern_osrelease_size, NULL, 0);
if (ret == 0) {
// get the major number, atoi will ignore the minor amd micro portions of the version string
if (atoi(kern_osrelease) >= OS_X_10_9_0_KERNEL_MAJOR_VERSION) {
*size = (DEFAULT_MAIN_THREAD_STACK_PAGES*getpagesize());
}
}
}
}
*bottom = (address) stacktop - *size;
#elif defined(__OpenBSD__)
stack_t ss;
int rslt = pthread_stackseg_np(pthread_self(), &ss);
if (rslt != 0)
fatal(err_msg("pthread_stackseg_np failed with err = %d", rslt));
*bottom = (address)((char *)ss.ss_sp - ss.ss_size);
*size = ss.ss_size;
#else
pthread_attr_t attr;
int rslt = pthread_attr_init(&attr);
// JVM needs to know exact stack location, abort if it fails
if (rslt != 0)
fatal(err_msg("pthread_attr_init failed with err = %d", rslt));
rslt = pthread_attr_get_np(pthread_self(), &attr);
if (rslt != 0)
fatal(err_msg("pthread_attr_get_np failed with err = %d", rslt));
if (pthread_attr_getstackaddr(&attr, (void **)bottom) != 0 ||
pthread_attr_getstacksize(&attr, size) != 0) {
fatal("Can not locate current stack attributes!");
}
pthread_attr_destroy(&attr);
#endif
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->context_rax);
st->print(", RBX=" INTPTR_FORMAT, uc->context_rbx);
st->print(", RCX=" INTPTR_FORMAT, uc->context_rcx);
st->print(", RDX=" INTPTR_FORMAT, uc->context_rdx);
st->cr();
st->print( "RSP=" INTPTR_FORMAT, uc->context_rsp);
st->print(", RBP=" INTPTR_FORMAT, uc->context_rbp);
st->print(", RSI=" INTPTR_FORMAT, uc->context_rsi);
st->print(", RDI=" INTPTR_FORMAT, uc->context_rdi);
st->cr();
st->print( "R8 =" INTPTR_FORMAT, uc->context_r8);
st->print(", R9 =" INTPTR_FORMAT, uc->context_r9);
st->print(", R10=" INTPTR_FORMAT, uc->context_r10);
st->print(", R11=" INTPTR_FORMAT, uc->context_r11);
st->cr();
st->print( "R12=" INTPTR_FORMAT, uc->context_r12);
st->print(", R13=" INTPTR_FORMAT, uc->context_r13);
st->print(", R14=" INTPTR_FORMAT, uc->context_r14);
st->print(", R15=" INTPTR_FORMAT, uc->context_r15);
st->cr();
st->print( "RIP=" INTPTR_FORMAT, uc->context_rip);
st->print(", EFLAGS=" INTPTR_FORMAT, uc->context_flags);
st->print(", ERR=" INTPTR_FORMAT, uc->context_err);
st->cr();
st->print(" TRAPNO=" INTPTR_FORMAT, uc->context_trapno);
#else
st->print( "EAX=" INTPTR_FORMAT, uc->context_eax);
st->print(", EBX=" INTPTR_FORMAT, uc->context_ebx);
st->print(", ECX=" INTPTR_FORMAT, uc->context_ecx);
st->print(", EDX=" INTPTR_FORMAT, uc->context_edx);
st->cr();
st->print( "ESP=" INTPTR_FORMAT, uc->context_esp);
st->print(", EBP=" INTPTR_FORMAT, uc->context_ebp);
st->print(", ESI=" INTPTR_FORMAT, uc->context_esi);
st->print(", EDI=" INTPTR_FORMAT, uc->context_edi);
st->cr();
st->print( "EIP=" INTPTR_FORMAT, uc->context_eip);
st->print(", EFLAGS=" INTPTR_FORMAT, uc->context_eflags);
#endif // AMD64
st->cr();
st->cr();
intptr_t *sp = (intptr_t *)os::Bsd::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::Bsd::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->context_rax);
st->print("RBX="); print_location(st, uc->context_rbx);
st->print("RCX="); print_location(st, uc->context_rcx);
st->print("RDX="); print_location(st, uc->context_rdx);
st->print("RSP="); print_location(st, uc->context_rsp);
st->print("RBP="); print_location(st, uc->context_rbp);
st->print("RSI="); print_location(st, uc->context_rsi);
st->print("RDI="); print_location(st, uc->context_rdi);
st->print("R8 ="); print_location(st, uc->context_r8);
st->print("R9 ="); print_location(st, uc->context_r9);
st->print("R10="); print_location(st, uc->context_r10);
st->print("R11="); print_location(st, uc->context_r11);
st->print("R12="); print_location(st, uc->context_r12);
st->print("R13="); print_location(st, uc->context_r13);
st->print("R14="); print_location(st, uc->context_r14);
st->print("R15="); print_location(st, uc->context_r15);
#else
st->print("EAX="); print_location(st, uc->context_eax);
st->print("EBX="); print_location(st, uc->context_ebx);
st->print("ECX="); print_location(st, uc->context_ecx);
st->print("EDX="); print_location(st, uc->context_edx);
st->print("ESP="); print_location(st, uc->context_esp);
st->print("EBP="); print_location(st, uc->context_ebp);
st->print("ESI="); print_location(st, uc->context_esi);
st->print("EDI="); print_location(st, uc->context_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() {
}
#endif
Other Java examples (source code examples)Here is a short list of links related to this Java os_bsd_x86.cpp source code file: |
The search page
Other Java source code examples at this package level
Click here to learn more about this project
