1 /*
   2  * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 // no precompiled headers
  26 #include "jvm.h"
  27 #include "assembler_arm.inline.hpp"
  28 #include "classfile/classLoader.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "classfile/vmSymbols.hpp"
  31 #include "code/icBuffer.hpp"
  32 #include "code/vtableStubs.hpp"
  33 #include "interpreter/interpreter.hpp"
  34 #include "memory/allocation.inline.hpp"
  35 #include "nativeInst_arm.hpp"
  36 #include "os_share_linux.hpp"
  37 #include "prims/jniFastGetField.hpp"
  38 #include "prims/jvm_misc.hpp"
  39 #include "runtime/arguments.hpp"
  40 #include "runtime/extendedPC.hpp"
  41 #include "runtime/frame.inline.hpp"
  42 #include "runtime/interfaceSupport.inline.hpp"
  43 #include "runtime/java.hpp"
  44 #include "runtime/javaCalls.hpp"
  45 #include "runtime/mutexLocker.hpp"
  46 #include "runtime/osThread.hpp"
  47 #include "runtime/sharedRuntime.hpp"
  48 #include "runtime/stubRoutines.hpp"
  49 #include "runtime/timer.hpp"
  50 #include "utilities/debug.hpp"
  51 #include "utilities/events.hpp"
  52 #include "utilities/vmError.hpp"
  53 
  54 // put OS-includes here
  55 # include <sys/types.h>
  56 # include <sys/mman.h>
  57 # include <pthread.h>
  58 # include <signal.h>
  59 # include <errno.h>
  60 # include <dlfcn.h>
  61 # include <stdlib.h>
  62 # include <stdio.h>
  63 # include <unistd.h>
  64 # include <sys/resource.h>
  65 # include <pthread.h>
  66 # include <sys/stat.h>
  67 # include <sys/time.h>
  68 # include <sys/utsname.h>
  69 # include <sys/socket.h>
  70 # include <sys/wait.h>
  71 # include <pwd.h>
  72 # include <poll.h>
  73 # include <ucontext.h>
  74 # include <fpu_control.h>
  75 # include <asm/ptrace.h>
  76 
  77 #define SPELL_REG_SP  "sp"
  78 
  79 // Don't #define SPELL_REG_FP for thumb because it is not safe to use, so this makes sure we never fetch it.
  80 #ifndef __thumb__
  81 #define SPELL_REG_FP "fp"
  82 #endif
  83 
  84 address os::current_stack_pointer() {
  85   register address sp __asm__ (SPELL_REG_SP);
  86   return sp;
  87 }
  88 
  89 char* os::non_memory_address_word() {
  90   // Must never look like an address returned by reserve_memory
  91   return (char*) -1;
  92 }
  93 
  94 
  95 #if NGREG == 16
  96 // These definitions are based on the observation that until
  97 // the certain version of GCC mcontext_t was defined as
  98 // a structure containing gregs[NGREG] array with 16 elements.
  99 // In later GCC versions mcontext_t was redefined as struct sigcontext,
 100 // along with NGREG constant changed to 18.
 101 #define arm_pc gregs[15]
 102 #define arm_sp gregs[13]
 103 #define arm_fp gregs[11]
 104 #define arm_r0 gregs[0]
 105 #endif
 106 
 107 #define ARM_REGS_IN_CONTEXT  16
 108 
 109 
 110 address os::Linux::ucontext_get_pc(const ucontext_t* uc) {
 111   return (address)uc->uc_mcontext.arm_pc;
 112 }
 113 
 114 void os::Linux::ucontext_set_pc(ucontext_t* uc, address pc) {
 115   uc->uc_mcontext.arm_pc = (uintx)pc;
 116 }
 117 
 118 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t* uc) {
 119   return (intptr_t*)uc->uc_mcontext.arm_sp;
 120 }
 121 
 122 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t* uc) {
 123   return (intptr_t*)uc->uc_mcontext.arm_fp;
 124 }
 125 
 126 bool is_safe_for_fp(address pc) {
 127 #ifdef __thumb__
 128   if (CodeCache::find_blob(pc) != NULL) {
 129     return true;
 130   }
 131   // For thumb C frames, given an fp we have no idea how to access the frame contents.
 132   return false;
 133 #else
 134   // Calling os::address_is_in_vm() here leads to a dladdr call. Calling any libc
 135   // function during os::get_native_stack() can result in a deadlock if JFR is
 136   // enabled. For now, be more lenient and allow all pc's. There are other
 137   // frame sanity checks in shared code, and to date they have been sufficient
 138   // for other platforms.
 139   //return os::address_is_in_vm(pc);
 140   return true;
 141 #endif
 142 }
 143 
 144 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
 145 // is currently interrupted by SIGPROF.
 146 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
 147 // frames. Currently we don't do that on Linux, so it's the same as
 148 // os::fetch_frame_from_context().
 149 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
 150   const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
 151 
 152   assert(thread != NULL, "just checking");
 153   assert(ret_sp != NULL, "just checking");
 154   assert(ret_fp != NULL, "just checking");
 155 
 156   return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
 157 }
 158 
 159 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
 160                     intptr_t** ret_sp, intptr_t** ret_fp) {
 161 
 162   ExtendedPC  epc;
 163   const ucontext_t* uc = (const ucontext_t*)ucVoid;
 164 
 165   if (uc != NULL) {
 166     epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
 167     if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
 168     if (ret_fp) {
 169       intptr_t* fp = os::Linux::ucontext_get_fp(uc);
 170 #ifndef __thumb__
 171       if (CodeCache::find_blob(epc.pc()) == NULL) {
 172         // It's a C frame. We need to adjust the fp.
 173         fp += os::C_frame_offset;
 174       }
 175 #endif
 176       // Clear FP when stack walking is dangerous so that
 177       // the frame created will not be walked.
 178       // However, ensure FP is set correctly when reliable and
 179       // potentially necessary.
 180       if (!is_safe_for_fp(epc.pc())) {
 181         // FP unreliable
 182         fp = (intptr_t *)NULL;
 183       }
 184       *ret_fp = fp;
 185     }
 186   } else {
 187     // construct empty ExtendedPC for return value checking
 188     epc = ExtendedPC(NULL);
 189     if (ret_sp) *ret_sp = (intptr_t *)NULL;
 190     if (ret_fp) *ret_fp = (intptr_t *)NULL;
 191   }
 192 
 193   return epc;
 194 }
 195 
 196 frame os::fetch_frame_from_context(const void* ucVoid) {
 197   intptr_t* sp;
 198   intptr_t* fp;
 199   ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
 200   return frame(sp, fp, epc.pc());
 201 }
 202 
 203 frame os::get_sender_for_C_frame(frame* fr) {
 204 #ifdef __thumb__
 205   // We can't reliably get anything from a thumb C frame.
 206   return frame();
 207 #else
 208   address pc = fr->sender_pc();
 209   if (! is_safe_for_fp(pc)) {
 210     return frame(fr->sender_sp(), (intptr_t *)NULL, pc);
 211   } else {
 212     return frame(fr->sender_sp(), fr->link() + os::C_frame_offset, pc);
 213   }
 214 #endif
 215 }
 216 
 217 //
 218 // This actually returns two frames up. It does not return os::current_frame(),
 219 // which is the actual current frame. Nor does it return os::get_native_stack(),
 220 // which is the caller. It returns whoever called os::get_native_stack(). Not
 221 // very intuitive, but consistent with how this API is implemented on other
 222 // platforms.
 223 //
 224 frame os::current_frame() {
 225 #ifdef __thumb__
 226   // We can't reliably get anything from a thumb C frame.
 227   return frame();
 228 #else
 229   register intptr_t* fp __asm__ (SPELL_REG_FP);
 230   // fp is for os::current_frame. We want the fp for our caller.
 231   frame myframe((intptr_t*)os::current_stack_pointer(), fp + os::C_frame_offset,
 232                  CAST_FROM_FN_PTR(address, os::current_frame));
 233   frame caller_frame = os::get_sender_for_C_frame(&myframe);
 234 
 235   if (os::is_first_C_frame(&caller_frame)) {
 236     // stack is not walkable
 237     // Assert below was added because it does not seem like this can ever happen.
 238     // How can this frame ever be the first C frame since it is called from C code?
 239     // If it does ever happen, undo the assert and comment here on when/why it happens.
 240     assert(false, "this should never happen");
 241     return frame();
 242   }
 243 
 244   // return frame for our caller's caller
 245   return os::get_sender_for_C_frame(&caller_frame);
 246 #endif
 247 }
 248 
 249 extern "C" address check_vfp_fault_instr;
 250 extern "C" address check_vfp3_32_fault_instr;
 251 
 252 address check_vfp_fault_instr = NULL;
 253 address check_vfp3_32_fault_instr = NULL;
 254 extern "C" address check_simd_fault_instr;
 255 address check_simd_fault_instr = NULL;
 256 
 257 // Utility functions
 258 
 259 extern "C" int JVM_handle_linux_signal(int sig, siginfo_t* info,
 260                                        void* ucVoid, int abort_if_unrecognized) {
 261   ucontext_t* uc = (ucontext_t*) ucVoid;
 262 
 263   Thread* t = Thread::current_or_null_safe();
 264 
 265   // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
 266   // (no destructors can be run)
 267   os::ThreadCrashProtection::check_crash_protection(sig, t);
 268 
 269   SignalHandlerMark shm(t);
 270 
 271   if (sig == SIGILL &&
 272       ((info->si_addr == (caddr_t)check_simd_fault_instr)
 273        || info->si_addr == (caddr_t)check_vfp_fault_instr
 274        || info->si_addr == (caddr_t)check_vfp3_32_fault_instr)) {
 275     // skip faulty instruction + instruction that sets return value to
 276     // success and set return value to failure.
 277     os::Linux::ucontext_set_pc(uc, (address)info->si_addr + 8);
 278     uc->uc_mcontext.arm_r0 = 0;
 279     return true;
 280   }
 281 
 282   // Note: it's not uncommon that JNI code uses signal/sigset to install
 283   // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
 284   // or have a SIGILL handler when detecting CPU type). When that happens,
 285   // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
 286   // avoid unnecessary crash when libjsig is not preloaded, try handle signals
 287   // that do not require siginfo/ucontext first.
 288 
 289   if (sig == SIGPIPE || sig == SIGXFSZ) {
 290     // allow chained handler to go first
 291     if (os::Linux::chained_handler(sig, info, ucVoid)) {
 292       return true;
 293     } else {
 294       // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
 295       return true;
 296     }
 297   }
 298 
 299 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
 300   if ((sig == SIGSEGV || sig == SIGBUS) && info != NULL && info->si_addr == g_assert_poison) {
 301     handle_assert_poison_fault(ucVoid, info->si_addr);
 302     return 1;
 303   }
 304 #endif
 305 
 306   JavaThread* thread = NULL;
 307   VMThread* vmthread = NULL;
 308   if (os::Linux::signal_handlers_are_installed) {
 309     if (t != NULL ){
 310       if(t->is_Java_thread()) {
 311         thread = (JavaThread*)t;
 312       }
 313       else if(t->is_VM_thread()){
 314         vmthread = (VMThread *)t;
 315       }
 316     }
 317   }
 318 
 319   address stub = NULL;
 320   address pc = NULL;
 321   bool unsafe_access = false;
 322 
 323   if (info != NULL && uc != NULL && thread != NULL) {
 324     pc = (address) os::Linux::ucontext_get_pc(uc);
 325 
 326     // Handle ALL stack overflow variations here
 327     if (sig == SIGSEGV) {
 328       address addr = (address) info->si_addr;
 329 
 330       if (StubRoutines::is_safefetch_fault(pc)) {
 331         os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
 332         return 1;
 333       }
 334       // check if fault address is within thread stack
 335       if (addr < thread->stack_base() &&
 336           addr >= thread->stack_base() - thread->stack_size()) {
 337         // stack overflow
 338         if (thread->in_stack_yellow_reserved_zone(addr)) {
 339           thread->disable_stack_yellow_reserved_zone();
 340           if (thread->thread_state() == _thread_in_Java) {
 341             // Throw a stack overflow exception.  Guard pages will be reenabled
 342             // while unwinding the stack.
 343             stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
 344           } else {
 345             // Thread was in the vm or native code.  Return and try to finish.
 346             return 1;
 347           }
 348         } else if (thread->in_stack_red_zone(addr)) {
 349           // Fatal red zone violation.  Disable the guard pages and fall through
 350           // to handle_unexpected_exception way down below.
 351           thread->disable_stack_red_zone();
 352           tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
 353         } else {
 354           // Accessing stack address below sp may cause SEGV if current
 355           // thread has MAP_GROWSDOWN stack. This should only happen when
 356           // current thread was created by user code with MAP_GROWSDOWN flag
 357           // and then attached to VM. See notes in os_linux.cpp.
 358           if (thread->osthread()->expanding_stack() == 0) {
 359              thread->osthread()->set_expanding_stack();
 360              if (os::Linux::manually_expand_stack(thread, addr)) {
 361                thread->osthread()->clear_expanding_stack();
 362                return 1;
 363              }
 364              thread->osthread()->clear_expanding_stack();
 365           } else {
 366              fatal("recursive segv. expanding stack.");
 367           }
 368         }
 369       }
 370     }
 371 
 372     if (thread->thread_state() == _thread_in_Java) {
 373       // Java thread running in Java code => find exception handler if any
 374       // a fault inside compiled code, the interpreter, or a stub
 375 
 376       if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
 377         stub = SharedRuntime::get_poll_stub(pc);
 378       } else if (sig == SIGBUS) {
 379         // BugId 4454115: A read from a MappedByteBuffer can fault
 380         // here if the underlying file has been truncated.
 381         // Do not crash the VM in such a case.
 382         CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
 383         CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
 384         if (nm != NULL && nm->has_unsafe_access()) {
 385           unsafe_access = true;
 386         }
 387       } else if (sig == SIGSEGV && !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
 388           // Determination of interpreter/vtable stub/compiled code null exception
 389           CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
 390           if (cb != NULL) {
 391             stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
 392           }
 393       } else if (sig == SIGILL && *(int *)pc == NativeInstruction::zombie_illegal_instruction) {
 394         // Zombie
 395         stub = SharedRuntime::get_handle_wrong_method_stub();
 396       }
 397     } else if (thread->thread_state() == _thread_in_vm &&
 398                sig == SIGBUS && thread->doing_unsafe_access()) {
 399         unsafe_access = true;
 400     }
 401 
 402     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
 403     // and the heap gets shrunk before the field access.
 404     if (sig == SIGSEGV || sig == SIGBUS) {
 405       address addr = JNI_FastGetField::find_slowcase_pc(pc);
 406       if (addr != (address)-1) {
 407         stub = addr;
 408       }
 409     }
 410 
 411     // Check to see if we caught the safepoint code in the
 412     // process of write protecting the memory serialization page.
 413     // It write enables the page immediately after protecting it
 414     // so we can just return to retry the write.
 415     if (sig == SIGSEGV && os::is_memory_serialize_page(thread, (address) info->si_addr)) {
 416       // Block current thread until the memory serialize page permission restored.
 417       os::block_on_serialize_page_trap();
 418       return true;
 419     }
 420   }
 421 
 422   if (unsafe_access && stub == NULL) {
 423     // it can be an unsafe access and we haven't found
 424     // any other suitable exception reason,
 425     // so assume it is an unsafe access.
 426     address next_pc = pc + Assembler::InstructionSize;
 427 #ifdef __thumb__
 428     if (uc->uc_mcontext.arm_cpsr & PSR_T_BIT) {
 429       next_pc = (address)((intptr_t)next_pc | 0x1);
 430     }
 431 #endif
 432 
 433     stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
 434   }
 435 
 436   if (stub != NULL) {
 437 #ifdef __thumb__
 438     if (uc->uc_mcontext.arm_cpsr & PSR_T_BIT) {
 439       intptr_t p = (intptr_t)pc | 0x1;
 440       pc = (address)p;
 441 
 442       // Clear Thumb mode bit if we're redirected into the ARM ISA based code
 443       if (((intptr_t)stub & 0x1) == 0) {
 444         uc->uc_mcontext.arm_cpsr &= ~PSR_T_BIT;
 445       }
 446     } else {
 447       // No Thumb2 compiled stubs are triggered from ARM ISA compiled JIT'd code today.
 448       // The support needs to be added if that changes
 449       assert((((intptr_t)stub & 0x1) == 0), "can't return to Thumb code");
 450     }
 451 #endif
 452 
 453     // save all thread context in case we need to restore it
 454     if (thread != NULL) thread->set_saved_exception_pc(pc);
 455 
 456     os::Linux::ucontext_set_pc(uc, stub);
 457     return true;
 458   }
 459 
 460   // signal-chaining
 461   if (os::Linux::chained_handler(sig, info, ucVoid)) {
 462      return true;
 463   }
 464 
 465   if (!abort_if_unrecognized) {
 466     // caller wants another chance, so give it to him
 467     return false;
 468   }
 469 
 470   if (pc == NULL && uc != NULL) {
 471     pc = os::Linux::ucontext_get_pc(uc);
 472   }
 473 
 474   // unmask current signal
 475   sigset_t newset;
 476   sigemptyset(&newset);
 477   sigaddset(&newset, sig);
 478   sigprocmask(SIG_UNBLOCK, &newset, NULL);
 479 
 480   VMError::report_and_die(t, sig, pc, info, ucVoid);
 481 
 482   ShouldNotReachHere();
 483   return false;
 484 }
 485 
 486 void os::Linux::init_thread_fpu_state(void) {
 487   os::setup_fpu();
 488 }
 489 
 490 int os::Linux::get_fpu_control_word(void) {
 491   return 0;
 492 }
 493 
 494 void os::Linux::set_fpu_control_word(int fpu_control) {
 495   // Nothing to do
 496 }
 497 
 498 void os::setup_fpu() {
 499 #if !defined(__SOFTFP__) && defined(__VFP_FP__)
 500   // Turn on IEEE-754 compliant VFP mode
 501   __asm__ volatile (
 502     "mov %%r0, #0;"
 503     "fmxr fpscr, %%r0"
 504     : /* no output */ : /* no input */ : "r0"
 505   );
 506 #endif
 507 }
 508 
 509 bool os::is_allocatable(size_t bytes) {
 510   return true;
 511 }
 512 
 513 ////////////////////////////////////////////////////////////////////////////////
 514 // thread stack
 515 
 516 // Minimum usable stack sizes required to get to user code. Space for
 517 // HotSpot guard pages is added later.
 518 size_t os::Posix::_compiler_thread_min_stack_allowed = (32 DEBUG_ONLY(+ 4)) * K;
 519 size_t os::Posix::_java_thread_min_stack_allowed = (32 DEBUG_ONLY(+ 4)) * K;
 520 size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
 521 
 522 // return default stack size for thr_type
 523 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
 524   // default stack size (compiler thread needs larger stack)
 525   size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
 526   return s;
 527 }
 528 
 529 /////////////////////////////////////////////////////////////////////////////
 530 // helper functions for fatal error handler
 531 
 532 void os::print_context(outputStream *st, const void *context) {
 533   if (context == NULL) return;
 534   const ucontext_t *uc = (const ucontext_t*)context;
 535 
 536   st->print_cr("Registers:");
 537   intx* reg_area = (intx*)&uc->uc_mcontext.arm_r0;
 538   for (int r = 0; r < ARM_REGS_IN_CONTEXT; r++) {
 539     st->print_cr("  %-3s = " INTPTR_FORMAT, as_Register(r)->name(), reg_area[r]);
 540   }
 541 #define U64_FORMAT "0x%016llx"
 542   // now print flag register
 543   st->print_cr("  %-4s = 0x%08lx", "cpsr",uc->uc_mcontext.arm_cpsr);
 544   st->cr();
 545 
 546   intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
 547   st->print_cr("Top of Stack: (sp=" INTPTR_FORMAT ")", p2i(sp));
 548   print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
 549   st->cr();
 550 
 551   // Note: it may be unsafe to inspect memory near pc. For example, pc may
 552   // point to garbage if entry point in an nmethod is corrupted. Leave
 553   // this at the end, and hope for the best.
 554   address pc = os::Linux::ucontext_get_pc(uc);
 555   st->print_cr("Instructions: (pc=" INTPTR_FORMAT ")", p2i(pc));
 556   print_hex_dump(st, pc - 32, pc + 32, Assembler::InstructionSize);
 557 }
 558 
 559 void os::print_register_info(outputStream *st, const void *context) {
 560   if (context == NULL) return;
 561 
 562   const ucontext_t *uc = (const ucontext_t*)context;
 563   intx* reg_area = (intx*)&uc->uc_mcontext.arm_r0;
 564 
 565   st->print_cr("Register to memory mapping:");
 566   st->cr();
 567   for (int r = 0; r < ARM_REGS_IN_CONTEXT; r++) {
 568     st->print_cr("  %-3s = " INTPTR_FORMAT, as_Register(r)->name(), reg_area[r]);
 569     print_location(st, reg_area[r]);
 570     st->cr();
 571   }
 572   st->cr();
 573 }
 574 
 575 
 576 
 577 typedef int64_t cmpxchg_long_func_t(int64_t, int64_t, volatile int64_t*);
 578 
 579 cmpxchg_long_func_t* os::atomic_cmpxchg_long_func = os::atomic_cmpxchg_long_bootstrap;
 580 
 581 int64_t os::atomic_cmpxchg_long_bootstrap(int64_t compare_value, int64_t exchange_value, volatile int64_t* dest) {
 582   // try to use the stub:
 583   cmpxchg_long_func_t* func = CAST_TO_FN_PTR(cmpxchg_long_func_t*, StubRoutines::atomic_cmpxchg_long_entry());
 584 
 585   if (func != NULL) {
 586     os::atomic_cmpxchg_long_func = func;
 587     return (*func)(compare_value, exchange_value, dest);
 588   }
 589   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 590 
 591   int64_t old_value = *dest;
 592   if (old_value == compare_value)
 593     *dest = exchange_value;
 594   return old_value;
 595 }
 596 typedef int64_t load_long_func_t(const volatile int64_t*);
 597 
 598 load_long_func_t* os::atomic_load_long_func = os::atomic_load_long_bootstrap;
 599 
 600 int64_t os::atomic_load_long_bootstrap(const volatile int64_t* src) {
 601   // try to use the stub:
 602   load_long_func_t* func = CAST_TO_FN_PTR(load_long_func_t*, StubRoutines::atomic_load_long_entry());
 603 
 604   if (func != NULL) {
 605     os::atomic_load_long_func = func;
 606     return (*func)(src);
 607   }
 608   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 609 
 610   int64_t old_value = *src;
 611   return old_value;
 612 }
 613 
 614 typedef void store_long_func_t(int64_t, volatile int64_t*);
 615 
 616 store_long_func_t* os::atomic_store_long_func = os::atomic_store_long_bootstrap;
 617 
 618 void os::atomic_store_long_bootstrap(int64_t val, volatile int64_t* dest) {
 619   // try to use the stub:
 620   store_long_func_t* func = CAST_TO_FN_PTR(store_long_func_t*, StubRoutines::atomic_store_long_entry());
 621 
 622   if (func != NULL) {
 623     os::atomic_store_long_func = func;
 624     return (*func)(val, dest);
 625   }
 626   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 627 
 628   *dest = val;
 629 }
 630 
 631 typedef int32_t  atomic_add_func_t(int32_t add_value, volatile int32_t *dest);
 632 
 633 atomic_add_func_t * os::atomic_add_func = os::atomic_add_bootstrap;
 634 
 635 int32_t  os::atomic_add_bootstrap(int32_t add_value, volatile int32_t *dest) {
 636   atomic_add_func_t * func = CAST_TO_FN_PTR(atomic_add_func_t*,
 637                                             StubRoutines::atomic_add_entry());
 638   if (func != NULL) {
 639     os::atomic_add_func = func;
 640     return (*func)(add_value, dest);
 641   }
 642 
 643   int32_t old_value = *dest;
 644   *dest = old_value + add_value;
 645   return (old_value + add_value);
 646 }
 647 
 648 typedef int32_t  atomic_xchg_func_t(int32_t exchange_value, volatile int32_t *dest);
 649 
 650 atomic_xchg_func_t * os::atomic_xchg_func = os::atomic_xchg_bootstrap;
 651 
 652 int32_t  os::atomic_xchg_bootstrap(int32_t exchange_value, volatile int32_t *dest) {
 653   atomic_xchg_func_t * func = CAST_TO_FN_PTR(atomic_xchg_func_t*,
 654                                             StubRoutines::atomic_xchg_entry());
 655   if (func != NULL) {
 656     os::atomic_xchg_func = func;
 657     return (*func)(exchange_value, dest);
 658   }
 659 
 660   int32_t old_value = *dest;
 661   *dest = exchange_value;
 662   return (old_value);
 663 }
 664 
 665 typedef int32_t cmpxchg_func_t(int32_t, int32_t, volatile int32_t*);
 666 
 667 cmpxchg_func_t* os::atomic_cmpxchg_func = os::atomic_cmpxchg_bootstrap;
 668 
 669 int32_t os::atomic_cmpxchg_bootstrap(int32_t compare_value, int32_t exchange_value, volatile int32_t* dest) {
 670   // try to use the stub:
 671   cmpxchg_func_t* func = CAST_TO_FN_PTR(cmpxchg_func_t*, StubRoutines::atomic_cmpxchg_entry());
 672 
 673   if (func != NULL) {
 674     os::atomic_cmpxchg_func = func;
 675     return (*func)(compare_value, exchange_value, dest);
 676   }
 677   assert(Threads::number_of_threads() == 0, "for bootstrap only");
 678 
 679   int32_t old_value = *dest;
 680   if (old_value == compare_value)
 681     *dest = exchange_value;
 682   return old_value;
 683 }
 684 
 685 
 686 #ifndef PRODUCT
 687 void os::verify_stack_alignment() {
 688 }
 689 #endif
 690 
 691 int os::extra_bang_size_in_bytes() {
 692   // ARM does not require an additional stack bang.
 693   return 0;
 694 }
 695