1 /*
   2  * Copyright (c) 1999, 2020, 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 "asm/macroAssembler.hpp"
  28 #include "classfile/classLoader.hpp"
  29 #include "classfile/systemDictionary.hpp"
  30 #include "classfile/vmSymbols.hpp"
  31 #include "code/codeCache.hpp"
  32 #include "code/icBuffer.hpp"
  33 #include "code/vtableStubs.hpp"
  34 #include "interpreter/interpreter.hpp"
  35 #include "logging/log.hpp"
  36 #include "memory/allocation.inline.hpp"
  37 #include "os_share_bsd.hpp"
  38 #include "prims/jniFastGetField.hpp"
  39 #include "prims/jvm_misc.hpp"
  40 #include "runtime/arguments.hpp"
  41 #include "runtime/extendedPC.hpp"
  42 #include "runtime/frame.inline.hpp"
  43 #include "runtime/interfaceSupport.inline.hpp"
  44 #include "runtime/java.hpp"
  45 #include "runtime/javaCalls.hpp"
  46 #include "runtime/mutexLocker.hpp"
  47 #include "runtime/osThread.hpp"
  48 #include "runtime/safepointMechanism.hpp"
  49 #include "runtime/sharedRuntime.hpp"
  50 #include "runtime/stubRoutines.hpp"
  51 #include "runtime/thread.inline.hpp"
  52 #include "runtime/timer.hpp"
  53 #include "utilities/align.hpp"
  54 #include "utilities/events.hpp"
  55 #include "utilities/vmError.hpp"
  56 
  57 // put OS-includes here
  58 # include <sys/types.h>
  59 # include <sys/mman.h>
  60 # include <pthread.h>
  61 # include <signal.h>
  62 # include <errno.h>
  63 # include <dlfcn.h>
  64 # include <stdlib.h>
  65 # include <stdio.h>
  66 # include <unistd.h>
  67 # include <sys/resource.h>
  68 # include <pthread.h>
  69 # include <sys/stat.h>
  70 # include <sys/time.h>
  71 # include <sys/utsname.h>
  72 # include <sys/socket.h>
  73 # include <sys/wait.h>
  74 # include <pwd.h>
  75 # include <poll.h>
  76 #ifndef __OpenBSD__
  77 # include <ucontext.h>
  78 #endif
  79 
  80 #if !defined(__APPLE__) && !defined(__NetBSD__)
  81 # include <pthread_np.h>
  82 #endif
  83 
  84 // needed by current_stack_region() workaround for Mavericks
  85 #if defined(__APPLE__)
  86 # include <errno.h>
  87 # include <sys/types.h>
  88 # include <sys/sysctl.h>
  89 # define DEFAULT_MAIN_THREAD_STACK_PAGES 2048
  90 # define OS_X_10_9_0_KERNEL_MAJOR_VERSION 13
  91 #endif
  92 
  93 #ifdef AMD64
  94 #define SPELL_REG_SP "rsp"
  95 #define SPELL_REG_FP "rbp"
  96 #else
  97 #define SPELL_REG_SP "esp"
  98 #define SPELL_REG_FP "ebp"
  99 #endif // AMD64
 100 
 101 #ifdef __FreeBSD__
 102 # define context_trapno uc_mcontext.mc_trapno
 103 # ifdef AMD64
 104 #  define context_pc uc_mcontext.mc_rip
 105 #  define context_sp uc_mcontext.mc_rsp
 106 #  define context_fp uc_mcontext.mc_rbp
 107 #  define context_rip uc_mcontext.mc_rip
 108 #  define context_rsp uc_mcontext.mc_rsp
 109 #  define context_rbp uc_mcontext.mc_rbp
 110 #  define context_rax uc_mcontext.mc_rax
 111 #  define context_rbx uc_mcontext.mc_rbx
 112 #  define context_rcx uc_mcontext.mc_rcx
 113 #  define context_rdx uc_mcontext.mc_rdx
 114 #  define context_rsi uc_mcontext.mc_rsi
 115 #  define context_rdi uc_mcontext.mc_rdi
 116 #  define context_r8  uc_mcontext.mc_r8
 117 #  define context_r9  uc_mcontext.mc_r9
 118 #  define context_r10 uc_mcontext.mc_r10
 119 #  define context_r11 uc_mcontext.mc_r11
 120 #  define context_r12 uc_mcontext.mc_r12
 121 #  define context_r13 uc_mcontext.mc_r13
 122 #  define context_r14 uc_mcontext.mc_r14
 123 #  define context_r15 uc_mcontext.mc_r15
 124 #  define context_flags uc_mcontext.mc_flags
 125 #  define context_err uc_mcontext.mc_err
 126 # else
 127 #  define context_pc uc_mcontext.mc_eip
 128 #  define context_sp uc_mcontext.mc_esp
 129 #  define context_fp uc_mcontext.mc_ebp
 130 #  define context_eip uc_mcontext.mc_eip
 131 #  define context_esp uc_mcontext.mc_esp
 132 #  define context_eax uc_mcontext.mc_eax
 133 #  define context_ebx uc_mcontext.mc_ebx
 134 #  define context_ecx uc_mcontext.mc_ecx
 135 #  define context_edx uc_mcontext.mc_edx
 136 #  define context_ebp uc_mcontext.mc_ebp
 137 #  define context_esi uc_mcontext.mc_esi
 138 #  define context_edi uc_mcontext.mc_edi
 139 #  define context_eflags uc_mcontext.mc_eflags
 140 #  define context_trapno uc_mcontext.mc_trapno
 141 # endif
 142 #endif
 143 
 144 #ifdef __APPLE__
 145 # if __DARWIN_UNIX03 && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5)
 146   // 10.5 UNIX03 member name prefixes
 147   #define DU3_PREFIX(s, m) __ ## s.__ ## m
 148 # else
 149   #define DU3_PREFIX(s, m) s ## . ## m
 150 # endif
 151 
 152 # ifdef AMD64
 153 #  define context_pc context_rip
 154 #  define context_sp context_rsp
 155 #  define context_fp context_rbp
 156 #  define context_rip uc_mcontext->DU3_PREFIX(ss,rip)
 157 #  define context_rsp uc_mcontext->DU3_PREFIX(ss,rsp)
 158 #  define context_rax uc_mcontext->DU3_PREFIX(ss,rax)
 159 #  define context_rbx uc_mcontext->DU3_PREFIX(ss,rbx)
 160 #  define context_rcx uc_mcontext->DU3_PREFIX(ss,rcx)
 161 #  define context_rdx uc_mcontext->DU3_PREFIX(ss,rdx)
 162 #  define context_rbp uc_mcontext->DU3_PREFIX(ss,rbp)
 163 #  define context_rsi uc_mcontext->DU3_PREFIX(ss,rsi)
 164 #  define context_rdi uc_mcontext->DU3_PREFIX(ss,rdi)
 165 #  define context_r8  uc_mcontext->DU3_PREFIX(ss,r8)
 166 #  define context_r9  uc_mcontext->DU3_PREFIX(ss,r9)
 167 #  define context_r10 uc_mcontext->DU3_PREFIX(ss,r10)
 168 #  define context_r11 uc_mcontext->DU3_PREFIX(ss,r11)
 169 #  define context_r12 uc_mcontext->DU3_PREFIX(ss,r12)
 170 #  define context_r13 uc_mcontext->DU3_PREFIX(ss,r13)
 171 #  define context_r14 uc_mcontext->DU3_PREFIX(ss,r14)
 172 #  define context_r15 uc_mcontext->DU3_PREFIX(ss,r15)
 173 #  define context_flags uc_mcontext->DU3_PREFIX(ss,rflags)
 174 #  define context_trapno uc_mcontext->DU3_PREFIX(es,trapno)
 175 #  define context_err uc_mcontext->DU3_PREFIX(es,err)
 176 # else
 177 #  define context_pc context_eip
 178 #  define context_sp context_esp
 179 #  define context_fp context_ebp
 180 #  define context_eip uc_mcontext->DU3_PREFIX(ss,eip)
 181 #  define context_esp uc_mcontext->DU3_PREFIX(ss,esp)
 182 #  define context_eax uc_mcontext->DU3_PREFIX(ss,eax)
 183 #  define context_ebx uc_mcontext->DU3_PREFIX(ss,ebx)
 184 #  define context_ecx uc_mcontext->DU3_PREFIX(ss,ecx)
 185 #  define context_edx uc_mcontext->DU3_PREFIX(ss,edx)
 186 #  define context_ebp uc_mcontext->DU3_PREFIX(ss,ebp)
 187 #  define context_esi uc_mcontext->DU3_PREFIX(ss,esi)
 188 #  define context_edi uc_mcontext->DU3_PREFIX(ss,edi)
 189 #  define context_eflags uc_mcontext->DU3_PREFIX(ss,eflags)
 190 #  define context_trapno uc_mcontext->DU3_PREFIX(es,trapno)
 191 # endif
 192 #endif
 193 
 194 #ifdef __OpenBSD__
 195 # define context_trapno sc_trapno
 196 # ifdef AMD64
 197 #  define context_pc sc_rip
 198 #  define context_sp sc_rsp
 199 #  define context_fp sc_rbp
 200 #  define context_rip sc_rip
 201 #  define context_rsp sc_rsp
 202 #  define context_rbp sc_rbp
 203 #  define context_rax sc_rax
 204 #  define context_rbx sc_rbx
 205 #  define context_rcx sc_rcx
 206 #  define context_rdx sc_rdx
 207 #  define context_rsi sc_rsi
 208 #  define context_rdi sc_rdi
 209 #  define context_r8  sc_r8
 210 #  define context_r9  sc_r9
 211 #  define context_r10 sc_r10
 212 #  define context_r11 sc_r11
 213 #  define context_r12 sc_r12
 214 #  define context_r13 sc_r13
 215 #  define context_r14 sc_r14
 216 #  define context_r15 sc_r15
 217 #  define context_flags sc_rflags
 218 #  define context_err sc_err
 219 # else
 220 #  define context_pc sc_eip
 221 #  define context_sp sc_esp
 222 #  define context_fp sc_ebp
 223 #  define context_eip sc_eip
 224 #  define context_esp sc_esp
 225 #  define context_eax sc_eax
 226 #  define context_ebx sc_ebx
 227 #  define context_ecx sc_ecx
 228 #  define context_edx sc_edx
 229 #  define context_ebp sc_ebp
 230 #  define context_esi sc_esi
 231 #  define context_edi sc_edi
 232 #  define context_eflags sc_eflags
 233 #  define context_trapno sc_trapno
 234 # endif
 235 #endif
 236 
 237 #ifdef __NetBSD__
 238 # define context_trapno uc_mcontext.__gregs[_REG_TRAPNO]
 239 # ifdef AMD64
 240 #  define __register_t __greg_t
 241 #  define context_pc uc_mcontext.__gregs[_REG_RIP]
 242 #  define context_sp uc_mcontext.__gregs[_REG_URSP]
 243 #  define context_fp uc_mcontext.__gregs[_REG_RBP]
 244 #  define context_rip uc_mcontext.__gregs[_REG_RIP]
 245 #  define context_rsp uc_mcontext.__gregs[_REG_URSP]
 246 #  define context_rax uc_mcontext.__gregs[_REG_RAX]
 247 #  define context_rbx uc_mcontext.__gregs[_REG_RBX]
 248 #  define context_rcx uc_mcontext.__gregs[_REG_RCX]
 249 #  define context_rdx uc_mcontext.__gregs[_REG_RDX]
 250 #  define context_rbp uc_mcontext.__gregs[_REG_RBP]
 251 #  define context_rsi uc_mcontext.__gregs[_REG_RSI]
 252 #  define context_rdi uc_mcontext.__gregs[_REG_RDI]
 253 #  define context_r8  uc_mcontext.__gregs[_REG_R8]
 254 #  define context_r9  uc_mcontext.__gregs[_REG_R9]
 255 #  define context_r10 uc_mcontext.__gregs[_REG_R10]
 256 #  define context_r11 uc_mcontext.__gregs[_REG_R11]
 257 #  define context_r12 uc_mcontext.__gregs[_REG_R12]
 258 #  define context_r13 uc_mcontext.__gregs[_REG_R13]
 259 #  define context_r14 uc_mcontext.__gregs[_REG_R14]
 260 #  define context_r15 uc_mcontext.__gregs[_REG_R15]
 261 #  define context_flags uc_mcontext.__gregs[_REG_RFL]
 262 #  define context_err uc_mcontext.__gregs[_REG_ERR]
 263 # else
 264 #  define context_pc uc_mcontext.__gregs[_REG_EIP]
 265 #  define context_sp uc_mcontext.__gregs[_REG_UESP]
 266 #  define context_fp uc_mcontext.__gregs[_REG_EBP]
 267 #  define context_eip uc_mcontext.__gregs[_REG_EIP]
 268 #  define context_esp uc_mcontext.__gregs[_REG_UESP]
 269 #  define context_eax uc_mcontext.__gregs[_REG_EAX]
 270 #  define context_ebx uc_mcontext.__gregs[_REG_EBX]
 271 #  define context_ecx uc_mcontext.__gregs[_REG_ECX]
 272 #  define context_edx uc_mcontext.__gregs[_REG_EDX]
 273 #  define context_ebp uc_mcontext.__gregs[_REG_EBP]
 274 #  define context_esi uc_mcontext.__gregs[_REG_ESI]
 275 #  define context_edi uc_mcontext.__gregs[_REG_EDI]
 276 #  define context_eflags uc_mcontext.__gregs[_REG_EFL]
 277 #  define context_trapno uc_mcontext.__gregs[_REG_TRAPNO]
 278 # endif
 279 #endif
 280 
 281 address os::current_stack_pointer() {
 282 #if defined(__clang__) || defined(__llvm__)
 283   void *esp;
 284   __asm__("mov %%" SPELL_REG_SP ", %0":"=r"(esp));
 285   return (address) esp;
 286 #else
 287   register void *esp __asm__ (SPELL_REG_SP);
 288   return (address) esp;
 289 #endif
 290 }
 291 
 292 char* os::non_memory_address_word() {
 293   // Must never look like an address returned by reserve_memory,
 294   // even in its subfields (as defined by the CPU immediate fields,
 295   // if the CPU splits constants across multiple instructions).
 296 
 297   return (char*) -1;
 298 }
 299 
 300 address os::Bsd::ucontext_get_pc(const ucontext_t * uc) {
 301   return (address)uc->context_pc;
 302 }
 303 
 304 void os::Bsd::ucontext_set_pc(ucontext_t * uc, address pc) {
 305   uc->context_pc = (intptr_t)pc ;
 306 }
 307 
 308 intptr_t* os::Bsd::ucontext_get_sp(const ucontext_t * uc) {
 309   return (intptr_t*)uc->context_sp;
 310 }
 311 
 312 intptr_t* os::Bsd::ucontext_get_fp(const ucontext_t * uc) {
 313   return (intptr_t*)uc->context_fp;
 314 }
 315 
 316 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
 317 // is currently interrupted by SIGPROF.
 318 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
 319 // frames. Currently we don't do that on Bsd, so it's the same as
 320 // os::fetch_frame_from_context().
 321 // This method is also used for stack overflow signal handling.
 322 ExtendedPC os::Bsd::fetch_frame_from_ucontext(Thread* thread,
 323   const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
 324 
 325   assert(thread != NULL, "just checking");
 326   assert(ret_sp != NULL, "just checking");
 327   assert(ret_fp != NULL, "just checking");
 328 
 329   return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
 330 }
 331 
 332 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
 333                     intptr_t** ret_sp, intptr_t** ret_fp) {
 334 
 335   ExtendedPC  epc;
 336   const ucontext_t* uc = (const ucontext_t*)ucVoid;
 337 
 338   if (uc != NULL) {
 339     epc = ExtendedPC(os::Bsd::ucontext_get_pc(uc));
 340     if (ret_sp) *ret_sp = os::Bsd::ucontext_get_sp(uc);
 341     if (ret_fp) *ret_fp = os::Bsd::ucontext_get_fp(uc);
 342   } else {
 343     // construct empty ExtendedPC for return value checking
 344     epc = ExtendedPC(NULL);
 345     if (ret_sp) *ret_sp = (intptr_t *)NULL;
 346     if (ret_fp) *ret_fp = (intptr_t *)NULL;
 347   }
 348 
 349   return epc;
 350 }
 351 
 352 frame os::fetch_frame_from_context(const void* ucVoid) {
 353   intptr_t* sp;
 354   intptr_t* fp;
 355   ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
 356   return frame(sp, fp, epc.pc());
 357 }
 358 
 359 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
 360   intptr_t* sp;
 361   intptr_t* fp;
 362   ExtendedPC epc = os::Bsd::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp);
 363   return frame(sp, fp, epc.pc());
 364 }
 365 
 366 bool os::Bsd::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
 367   address pc = (address) os::Bsd::ucontext_get_pc(uc);
 368   if (Interpreter::contains(pc)) {
 369     // interpreter performs stack banging after the fixed frame header has
 370     // been generated while the compilers perform it before. To maintain
 371     // semantic consistency between interpreted and compiled frames, the
 372     // method returns the Java sender of the current frame.
 373     *fr = os::fetch_frame_from_ucontext(thread, uc);
 374     if (!fr->is_first_java_frame()) {
 375       // get_frame_at_stack_banging_point() is only called when we
 376       // have well defined stacks so java_sender() calls do not need
 377       // to assert safe_for_sender() first.
 378       *fr = fr->java_sender();
 379     }
 380   } else {
 381     // more complex code with compiled code
 382     assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
 383     CodeBlob* cb = CodeCache::find_blob(pc);
 384     if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
 385       // Not sure where the pc points to, fallback to default
 386       // stack overflow handling
 387       return false;
 388     } else {
 389       *fr = os::fetch_frame_from_ucontext(thread, uc);
 390       // in compiled code, the stack banging is performed just after the return pc
 391       // has been pushed on the stack
 392       *fr = frame(fr->sp() + 1, fr->fp(), (address)*(fr->sp()));
 393       if (!fr->is_java_frame()) {
 394         // See java_sender() comment above.
 395         *fr = fr->java_sender();
 396       }
 397     }
 398   }
 399   assert(fr->is_java_frame(), "Safety check");
 400   return true;
 401 }
 402 
 403 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
 404 // turned off by -fomit-frame-pointer,
 405 frame os::get_sender_for_C_frame(frame* fr) {
 406   return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
 407 }
 408 
 409 intptr_t* _get_previous_fp() {
 410 #if defined(__clang__) || defined(__llvm__)
 411   intptr_t **ebp;
 412   __asm__("mov %%" SPELL_REG_FP ", %0":"=r"(ebp));
 413 #else
 414   register intptr_t **ebp __asm__ (SPELL_REG_FP);
 415 #endif
 416   // ebp is for this frame (_get_previous_fp). We want the ebp for the
 417   // caller of os::current_frame*(), so go up two frames. However, for
 418   // optimized builds, _get_previous_fp() will be inlined, so only go
 419   // up 1 frame in that case.
 420 #ifdef _NMT_NOINLINE_
 421   return **(intptr_t***)ebp;
 422 #else
 423   return *ebp;
 424 #endif
 425 }
 426 
 427 
 428 frame os::current_frame() {
 429   intptr_t* fp = _get_previous_fp();
 430   frame myframe((intptr_t*)os::current_stack_pointer(),
 431                 (intptr_t*)fp,
 432                 CAST_FROM_FN_PTR(address, os::current_frame));
 433   if (os::is_first_C_frame(&myframe)) {
 434     // stack is not walkable
 435     return frame();
 436   } else {
 437     return os::get_sender_for_C_frame(&myframe);
 438   }
 439 }
 440 
 441 // Utility functions
 442 
 443 // From IA32 System Programming Guide
 444 enum {
 445   trap_page_fault = 0xE
 446 };
 447 
 448 extern "C" JNIEXPORT int
 449 JVM_handle_bsd_signal(int sig,
 450                         siginfo_t* info,
 451                         void* ucVoid,
 452                         int abort_if_unrecognized) {
 453   ucontext_t* uc = (ucontext_t*) ucVoid;
 454 
 455   Thread* t = Thread::current_or_null_safe();
 456 
 457   // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
 458   // (no destructors can be run)
 459   os::ThreadCrashProtection::check_crash_protection(sig, t);
 460 
 461   SignalHandlerMark shm(t);
 462 
 463   // Note: it's not uncommon that JNI code uses signal/sigset to install
 464   // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
 465   // or have a SIGILL handler when detecting CPU type). When that happens,
 466   // JVM_handle_bsd_signal() might be invoked with junk info/ucVoid. To
 467   // avoid unnecessary crash when libjsig is not preloaded, try handle signals
 468   // that do not require siginfo/ucontext first.
 469 
 470   if (sig == SIGPIPE || sig == SIGXFSZ) {
 471     // allow chained handler to go first
 472     if (os::Bsd::chained_handler(sig, info, ucVoid)) {
 473       return true;
 474     } else {
 475       // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
 476       return true;
 477     }
 478   }
 479 
 480   JavaThread* thread = NULL;
 481   VMThread* vmthread = NULL;
 482   if (os::Bsd::signal_handlers_are_installed) {
 483     if (t != NULL ){
 484       if(t->is_Java_thread()) {
 485         thread = (JavaThread*)t;
 486       }
 487       else if(t->is_VM_thread()){
 488         vmthread = (VMThread *)t;
 489       }
 490     }
 491   }
 492 /*
 493   NOTE: does not seem to work on bsd.
 494   if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
 495     // can't decode this kind of signal
 496     info = NULL;
 497   } else {
 498     assert(sig == info->si_signo, "bad siginfo");
 499   }
 500 */
 501   // decide if this trap can be handled by a stub
 502   address stub = NULL;
 503 
 504   address pc          = NULL;
 505 
 506   //%note os_trap_1
 507   if (info != NULL && uc != NULL && thread != NULL) {
 508     pc = (address) os::Bsd::ucontext_get_pc(uc);
 509 
 510     if (StubRoutines::is_safefetch_fault(pc)) {
 511       os::Bsd::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
 512       return 1;
 513     }
 514 
 515     // Handle ALL stack overflow variations here
 516     if (sig == SIGSEGV || sig == SIGBUS) {
 517       address addr = (address) info->si_addr;
 518 
 519       // check if fault address is within thread stack
 520       if (thread->is_in_full_stack(addr)) {
 521         // stack overflow
 522         if (thread->in_stack_yellow_reserved_zone(addr)) {
 523           if (thread->thread_state() == _thread_in_Java) {
 524             if (thread->in_stack_reserved_zone(addr)) {
 525               frame fr;
 526               if (os::Bsd::get_frame_at_stack_banging_point(thread, uc, &fr)) {
 527                 assert(fr.is_java_frame(), "Must be a Java frame");
 528                 frame activation = SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
 529                 if (activation.sp() != NULL) {
 530                   thread->disable_stack_reserved_zone();
 531                   if (activation.is_interpreted_frame()) {
 532                     thread->set_reserved_stack_activation((address)(
 533                       activation.fp() + frame::interpreter_frame_initial_sp_offset));
 534                   } else {
 535                     thread->set_reserved_stack_activation((address)activation.unextended_sp());
 536                   }
 537                   return 1;
 538                 }
 539               }
 540             }
 541             // Throw a stack overflow exception.  Guard pages will be reenabled
 542             // while unwinding the stack.
 543             thread->disable_stack_yellow_reserved_zone();
 544             stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
 545           } else {
 546             // Thread was in the vm or native code.  Return and try to finish.
 547             thread->disable_stack_yellow_reserved_zone();
 548             return 1;
 549           }
 550         } else if (thread->in_stack_red_zone(addr)) {
 551           // Fatal red zone violation.  Disable the guard pages and fall through
 552           // to handle_unexpected_exception way down below.
 553           thread->disable_stack_red_zone();
 554           tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
 555         }
 556       }
 557     }
 558 
 559     if ((sig == SIGSEGV || sig == SIGBUS) && VM_Version::is_cpuinfo_segv_addr(pc)) {
 560       // Verify that OS save/restore AVX registers.
 561       stub = VM_Version::cpuinfo_cont_addr();
 562     }
 563 
 564     // We test if stub is already set (by the stack overflow code
 565     // above) so it is not overwritten by the code that follows. This
 566     // check is not required on other platforms, because on other
 567     // platforms we check for SIGSEGV only or SIGBUS only, where here
 568     // we have to check for both SIGSEGV and SIGBUS.
 569     if (thread->thread_state() == _thread_in_Java && stub == NULL) {
 570       // Java thread running in Java code => find exception handler if any
 571       // a fault inside compiled code, the interpreter, or a stub
 572 
 573       if ((sig == SIGSEGV || sig == SIGBUS) && SafepointMechanism::is_poll_address((address)info->si_addr)) {
 574         stub = SharedRuntime::get_poll_stub(pc);
 575 #if defined(__APPLE__)
 576       // 32-bit Darwin reports a SIGBUS for nearly all memory access exceptions.
 577       // 64-bit Darwin may also use a SIGBUS (seen with compressed oops).
 578       // Catching SIGBUS here prevents the implicit SIGBUS NULL check below from
 579       // being called, so only do so if the implicit NULL check is not necessary.
 580       } else if (sig == SIGBUS && !MacroAssembler::uses_implicit_null_check(info->si_addr)) {
 581 #else
 582       } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
 583 #endif
 584         // BugId 4454115: A read from a MappedByteBuffer can fault
 585         // here if the underlying file has been truncated.
 586         // Do not crash the VM in such a case.
 587         CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
 588         CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
 589         bool is_unsafe_arraycopy = thread->doing_unsafe_access() && UnsafeCopyMemory::contains_pc(pc);
 590         if ((nm != NULL && nm->has_unsafe_access()) || is_unsafe_arraycopy) {
 591           address next_pc = Assembler::locate_next_instruction(pc);
 592           if (is_unsafe_arraycopy) {
 593             next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
 594           }
 595           stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
 596         }
 597       }
 598       else
 599 
 600 #ifdef AMD64
 601       if (sig == SIGFPE  &&
 602           (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
 603         stub =
 604           SharedRuntime::
 605           continuation_for_implicit_exception(thread,
 606                                               pc,
 607                                               SharedRuntime::
 608                                               IMPLICIT_DIVIDE_BY_ZERO);
 609 #ifdef __APPLE__
 610       } else if (sig == SIGFPE && info->si_code == FPE_NOOP) {
 611         int op = pc[0];
 612 
 613         // Skip REX
 614         if ((pc[0] & 0xf0) == 0x40) {
 615           op = pc[1];
 616         } else {
 617           op = pc[0];
 618         }
 619 
 620         // Check for IDIV
 621         if (op == 0xF7) {
 622           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime:: IMPLICIT_DIVIDE_BY_ZERO);
 623         } else {
 624           // TODO: handle more cases if we are using other x86 instructions
 625           //   that can generate SIGFPE signal.
 626           tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
 627           fatal("please update this code.");
 628         }
 629 #endif /* __APPLE__ */
 630 
 631 #else
 632       if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
 633         // HACK: si_code does not work on bsd 2.2.12-20!!!
 634         int op = pc[0];
 635         if (op == 0xDB) {
 636           // FIST
 637           // TODO: The encoding of D2I in i486.ad can cause an exception
 638           // prior to the fist instruction if there was an invalid operation
 639           // pending. We want to dismiss that exception. From the win_32
 640           // side it also seems that if it really was the fist causing
 641           // the exception that we do the d2i by hand with different
 642           // rounding. Seems kind of weird.
 643           // NOTE: that we take the exception at the NEXT floating point instruction.
 644           assert(pc[0] == 0xDB, "not a FIST opcode");
 645           assert(pc[1] == 0x14, "not a FIST opcode");
 646           assert(pc[2] == 0x24, "not a FIST opcode");
 647           return true;
 648         } else if (op == 0xF7) {
 649           // IDIV
 650           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
 651         } else {
 652           // TODO: handle more cases if we are using other x86 instructions
 653           //   that can generate SIGFPE signal on bsd.
 654           tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
 655           fatal("please update this code.");
 656         }
 657 #endif // AMD64
 658       } else if ((sig == SIGSEGV || sig == SIGBUS) &&
 659                  MacroAssembler::uses_implicit_null_check(info->si_addr)) {
 660           // Determination of interpreter/vtable stub/compiled code null exception
 661           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
 662       }
 663     } else if ((thread->thread_state() == _thread_in_vm ||
 664                 thread->thread_state() == _thread_in_native) &&
 665                sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
 666                thread->doing_unsafe_access()) {
 667         address next_pc = Assembler::locate_next_instruction(pc);
 668         if (UnsafeCopyMemory::contains_pc(pc)) {
 669           next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
 670         }
 671         stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
 672     }
 673 
 674     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
 675     // and the heap gets shrunk before the field access.
 676     if ((sig == SIGSEGV) || (sig == SIGBUS)) {
 677       address addr = JNI_FastGetField::find_slowcase_pc(pc);
 678       if (addr != (address)-1) {
 679         stub = addr;
 680       }
 681     }
 682   }
 683 
 684 #ifndef AMD64
 685   // Execution protection violation
 686   //
 687   // This should be kept as the last step in the triage.  We don't
 688   // have a dedicated trap number for a no-execute fault, so be
 689   // conservative and allow other handlers the first shot.
 690   //
 691   // Note: We don't test that info->si_code == SEGV_ACCERR here.
 692   // this si_code is so generic that it is almost meaningless; and
 693   // the si_code for this condition may change in the future.
 694   // Furthermore, a false-positive should be harmless.
 695   if (UnguardOnExecutionViolation > 0 &&
 696       (sig == SIGSEGV || sig == SIGBUS) &&
 697       uc->context_trapno == trap_page_fault) {
 698     int page_size = os::vm_page_size();
 699     address addr = (address) info->si_addr;
 700     address pc = os::Bsd::ucontext_get_pc(uc);
 701     // Make sure the pc and the faulting address are sane.
 702     //
 703     // If an instruction spans a page boundary, and the page containing
 704     // the beginning of the instruction is executable but the following
 705     // page is not, the pc and the faulting address might be slightly
 706     // different - we still want to unguard the 2nd page in this case.
 707     //
 708     // 15 bytes seems to be a (very) safe value for max instruction size.
 709     bool pc_is_near_addr =
 710       (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
 711     bool instr_spans_page_boundary =
 712       (align_down((intptr_t) pc ^ (intptr_t) addr,
 713                        (intptr_t) page_size) > 0);
 714 
 715     if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
 716       static volatile address last_addr =
 717         (address) os::non_memory_address_word();
 718 
 719       // In conservative mode, don't unguard unless the address is in the VM
 720       if (addr != last_addr &&
 721           (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
 722 
 723         // Set memory to RWX and retry
 724         address page_start = align_down(addr, page_size);
 725         bool res = os::protect_memory((char*) page_start, page_size,
 726                                       os::MEM_PROT_RWX);
 727 
 728         log_debug(os)("Execution protection violation "
 729                       "at " INTPTR_FORMAT
 730                       ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
 731                       p2i(page_start), (res ? "success" : "failed"), errno);
 732         stub = pc;
 733 
 734         // Set last_addr so if we fault again at the same address, we don't end
 735         // up in an endless loop.
 736         //
 737         // There are two potential complications here.  Two threads trapping at
 738         // the same address at the same time could cause one of the threads to
 739         // think it already unguarded, and abort the VM.  Likely very rare.
 740         //
 741         // The other race involves two threads alternately trapping at
 742         // different addresses and failing to unguard the page, resulting in
 743         // an endless loop.  This condition is probably even more unlikely than
 744         // the first.
 745         //
 746         // Although both cases could be avoided by using locks or thread local
 747         // last_addr, these solutions are unnecessary complication: this
 748         // handler is a best-effort safety net, not a complete solution.  It is
 749         // disabled by default and should only be used as a workaround in case
 750         // we missed any no-execute-unsafe VM code.
 751 
 752         last_addr = addr;
 753       }
 754     }
 755   }
 756 #endif // !AMD64
 757 
 758   if (stub != NULL) {
 759     // save all thread context in case we need to restore it
 760     if (thread != NULL) thread->set_saved_exception_pc(pc);
 761 
 762     os::Bsd::ucontext_set_pc(uc, stub);
 763     return true;
 764   }
 765 
 766   // signal-chaining
 767   if (os::Bsd::chained_handler(sig, info, ucVoid)) {
 768      return true;
 769   }
 770 
 771   if (!abort_if_unrecognized) {
 772     // caller wants another chance, so give it to him
 773     return false;
 774   }
 775 
 776   if (pc == NULL && uc != NULL) {
 777     pc = os::Bsd::ucontext_get_pc(uc);
 778   }
 779 
 780   // unmask current signal
 781   sigset_t newset;
 782   sigemptyset(&newset);
 783   sigaddset(&newset, sig);
 784   sigprocmask(SIG_UNBLOCK, &newset, NULL);
 785 
 786   VMError::report_and_die(t, sig, pc, info, ucVoid);
 787 
 788   ShouldNotReachHere();
 789   return false;
 790 }
 791 
 792 // From solaris_i486.s ported to bsd_i486.s
 793 extern "C" void fixcw();
 794 
 795 void os::Bsd::init_thread_fpu_state(void) {
 796 #ifndef AMD64
 797   // Set fpu to 53 bit precision. This happens too early to use a stub.
 798   fixcw();
 799 #endif // !AMD64
 800 }
 801 
 802 
 803 // Check that the bsd kernel version is 2.4 or higher since earlier
 804 // versions do not support SSE without patches.
 805 bool os::supports_sse() {
 806   return true;
 807 }
 808 
 809 bool os::is_allocatable(size_t bytes) {
 810 #ifdef AMD64
 811   // unused on amd64?
 812   return true;
 813 #else
 814 
 815   if (bytes < 2 * G) {
 816     return true;
 817   }
 818 
 819   char* addr = reserve_memory(bytes, NULL);
 820 
 821   if (addr != NULL) {
 822     release_memory(addr, bytes);
 823   }
 824 
 825   return addr != NULL;
 826 #endif // AMD64
 827 }
 828 
 829 ////////////////////////////////////////////////////////////////////////////////
 830 // thread stack
 831 
 832 // Minimum usable stack sizes required to get to user code. Space for
 833 // HotSpot guard pages is added later.
 834 size_t os::Posix::_compiler_thread_min_stack_allowed = 48 * K;
 835 size_t os::Posix::_java_thread_min_stack_allowed = 48 * K;
 836 #ifdef _LP64
 837 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
 838 #else
 839 size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
 840 #endif // _LP64
 841 
 842 #ifndef AMD64
 843 #ifdef __GNUC__
 844 #define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})
 845 #endif
 846 #endif // AMD64
 847 
 848 // return default stack size for thr_type
 849 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
 850   // default stack size (compiler thread needs larger stack)
 851 #ifdef AMD64
 852   size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
 853 #else
 854   size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
 855 #endif // AMD64
 856   return s;
 857 }
 858 
 859 
 860 // Java thread:
 861 //
 862 //   Low memory addresses
 863 //    +------------------------+
 864 //    |                        |\  Java thread created by VM does not have glibc
 865 //    |    glibc guard page    | - guard, attached Java thread usually has
 866 //    |                        |/  1 glibc guard page.
 867 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
 868 //    |                        |\
 869 //    |  HotSpot Guard Pages   | - red, yellow and reserved pages
 870 //    |                        |/
 871 //    +------------------------+ JavaThread::stack_reserved_zone_base()
 872 //    |                        |\
 873 //    |      Normal Stack      | -
 874 //    |                        |/
 875 // P2 +------------------------+ Thread::stack_base()
 876 //
 877 // Non-Java thread:
 878 //
 879 //   Low memory addresses
 880 //    +------------------------+
 881 //    |                        |\
 882 //    |  glibc guard page      | - usually 1 page
 883 //    |                        |/
 884 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
 885 //    |                        |\
 886 //    |      Normal Stack      | -
 887 //    |                        |/
 888 // P2 +------------------------+ Thread::stack_base()
 889 //
 890 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
 891 //    pthread_attr_getstack()
 892 
 893 static void current_stack_region(address * bottom, size_t * size) {
 894 #ifdef __APPLE__
 895   pthread_t self = pthread_self();
 896   void *stacktop = pthread_get_stackaddr_np(self);
 897   *size = pthread_get_stacksize_np(self);
 898   // workaround for OS X 10.9.0 (Mavericks)
 899   // pthread_get_stacksize_np returns 128 pages even though the actual size is 2048 pages
 900   if (pthread_main_np() == 1) {
 901     // At least on Mac OS 10.12 we have observed stack sizes not aligned
 902     // to pages boundaries. This can be provoked by e.g. setrlimit() (ulimit -s xxxx in the
 903     // shell). Apparently Mac OS actually rounds upwards to next multiple of page size,
 904     // however, we round downwards here to be on the safe side.
 905     *size = align_down(*size, getpagesize());
 906 
 907     if ((*size) < (DEFAULT_MAIN_THREAD_STACK_PAGES * (size_t)getpagesize())) {
 908       char kern_osrelease[256];
 909       size_t kern_osrelease_size = sizeof(kern_osrelease);
 910       int ret = sysctlbyname("kern.osrelease", kern_osrelease, &kern_osrelease_size, NULL, 0);
 911       if (ret == 0) {
 912         // get the major number, atoi will ignore the minor amd micro portions of the version string
 913         if (atoi(kern_osrelease) >= OS_X_10_9_0_KERNEL_MAJOR_VERSION) {
 914           *size = (DEFAULT_MAIN_THREAD_STACK_PAGES*getpagesize());
 915         }
 916       }
 917     }
 918   }
 919   *bottom = (address) stacktop - *size;
 920 #elif defined(__OpenBSD__)
 921   stack_t ss;
 922   int rslt = pthread_stackseg_np(pthread_self(), &ss);
 923 
 924   if (rslt != 0)
 925     fatal("pthread_stackseg_np failed with error = %d", rslt);
 926 
 927   *bottom = (address)((char *)ss.ss_sp - ss.ss_size);
 928   *size   = ss.ss_size;
 929 #else
 930   pthread_attr_t attr;
 931 
 932   int rslt = pthread_attr_init(&attr);
 933 
 934   // JVM needs to know exact stack location, abort if it fails
 935   if (rslt != 0)
 936     fatal("pthread_attr_init failed with error = %d", rslt);
 937 
 938   rslt = pthread_attr_get_np(pthread_self(), &attr);
 939 
 940   if (rslt != 0)
 941     fatal("pthread_attr_get_np failed with error = %d", rslt);
 942 
 943   if (pthread_attr_getstackaddr(&attr, (void **)bottom) != 0 ||
 944     pthread_attr_getstacksize(&attr, size) != 0) {
 945     fatal("Can not locate current stack attributes!");
 946   }
 947 
 948   pthread_attr_destroy(&attr);
 949 #endif
 950   assert(os::current_stack_pointer() >= *bottom &&
 951          os::current_stack_pointer() < *bottom + *size, "just checking");
 952 }
 953 
 954 address os::current_stack_base() {
 955   address bottom;
 956   size_t size;
 957   current_stack_region(&bottom, &size);
 958   return (bottom + size);
 959 }
 960 
 961 size_t os::current_stack_size() {
 962   // stack size includes normal stack and HotSpot guard pages
 963   address bottom;
 964   size_t size;
 965   current_stack_region(&bottom, &size);
 966   return size;
 967 }
 968 
 969 /////////////////////////////////////////////////////////////////////////////
 970 // helper functions for fatal error handler
 971 
 972 void os::print_context(outputStream *st, const void *context) {
 973   if (context == NULL) return;
 974 
 975   const ucontext_t *uc = (const ucontext_t*)context;
 976   st->print_cr("Registers:");
 977 #ifdef AMD64
 978   st->print(  "RAX=" INTPTR_FORMAT, (intptr_t)uc->context_rax);
 979   st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->context_rbx);
 980   st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->context_rcx);
 981   st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->context_rdx);
 982   st->cr();
 983   st->print(  "RSP=" INTPTR_FORMAT, (intptr_t)uc->context_rsp);
 984   st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->context_rbp);
 985   st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->context_rsi);
 986   st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->context_rdi);
 987   st->cr();
 988   st->print(  "R8 =" INTPTR_FORMAT, (intptr_t)uc->context_r8);
 989   st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->context_r9);
 990   st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->context_r10);
 991   st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->context_r11);
 992   st->cr();
 993   st->print(  "R12=" INTPTR_FORMAT, (intptr_t)uc->context_r12);
 994   st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->context_r13);
 995   st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->context_r14);
 996   st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->context_r15);
 997   st->cr();
 998   st->print(  "RIP=" INTPTR_FORMAT, (intptr_t)uc->context_rip);
 999   st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->context_flags);
1000   st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->context_err);
1001   st->cr();
1002   st->print("  TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->context_trapno);
1003 #else
1004   st->print(  "EAX=" INTPTR_FORMAT, (intptr_t)uc->context_eax);
1005   st->print(", EBX=" INTPTR_FORMAT, (intptr_t)uc->context_ebx);
1006   st->print(", ECX=" INTPTR_FORMAT, (intptr_t)uc->context_ecx);
1007   st->print(", EDX=" INTPTR_FORMAT, (intptr_t)uc->context_edx);
1008   st->cr();
1009   st->print(  "ESP=" INTPTR_FORMAT, (intptr_t)uc->context_esp);
1010   st->print(", EBP=" INTPTR_FORMAT, (intptr_t)uc->context_ebp);
1011   st->print(", ESI=" INTPTR_FORMAT, (intptr_t)uc->context_esi);
1012   st->print(", EDI=" INTPTR_FORMAT, (intptr_t)uc->context_edi);
1013   st->cr();
1014   st->print(  "EIP=" INTPTR_FORMAT, (intptr_t)uc->context_eip);
1015   st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->context_eflags);
1016 #endif // AMD64
1017   st->cr();
1018   st->cr();
1019 
1020   intptr_t *sp = (intptr_t *)os::Bsd::ucontext_get_sp(uc);
1021   st->print_cr("Top of Stack: (sp=" INTPTR_FORMAT ")", (intptr_t)sp);
1022   print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
1023   st->cr();
1024 
1025   // Note: it may be unsafe to inspect memory near pc. For example, pc may
1026   // point to garbage if entry point in an nmethod is corrupted. Leave
1027   // this at the end, and hope for the best.
1028   address pc = os::Bsd::ucontext_get_pc(uc);
1029   print_instructions(st, pc, sizeof(char));
1030   st->cr();
1031 }
1032 
1033 void os::print_register_info(outputStream *st, const void *context) {
1034   if (context == NULL) return;
1035 
1036   const ucontext_t *uc = (const ucontext_t*)context;
1037 
1038   st->print_cr("Register to memory mapping:");
1039   st->cr();
1040 
1041   // this is horrendously verbose but the layout of the registers in the
1042   // context does not match how we defined our abstract Register set, so
1043   // we can't just iterate through the gregs area
1044 
1045   // this is only for the "general purpose" registers
1046 
1047 #ifdef AMD64
1048   st->print("RAX="); print_location(st, uc->context_rax);
1049   st->print("RBX="); print_location(st, uc->context_rbx);
1050   st->print("RCX="); print_location(st, uc->context_rcx);
1051   st->print("RDX="); print_location(st, uc->context_rdx);
1052   st->print("RSP="); print_location(st, uc->context_rsp);
1053   st->print("RBP="); print_location(st, uc->context_rbp);
1054   st->print("RSI="); print_location(st, uc->context_rsi);
1055   st->print("RDI="); print_location(st, uc->context_rdi);
1056   st->print("R8 ="); print_location(st, uc->context_r8);
1057   st->print("R9 ="); print_location(st, uc->context_r9);
1058   st->print("R10="); print_location(st, uc->context_r10);
1059   st->print("R11="); print_location(st, uc->context_r11);
1060   st->print("R12="); print_location(st, uc->context_r12);
1061   st->print("R13="); print_location(st, uc->context_r13);
1062   st->print("R14="); print_location(st, uc->context_r14);
1063   st->print("R15="); print_location(st, uc->context_r15);
1064 #else
1065   st->print("EAX="); print_location(st, uc->context_eax);
1066   st->print("EBX="); print_location(st, uc->context_ebx);
1067   st->print("ECX="); print_location(st, uc->context_ecx);
1068   st->print("EDX="); print_location(st, uc->context_edx);
1069   st->print("ESP="); print_location(st, uc->context_esp);
1070   st->print("EBP="); print_location(st, uc->context_ebp);
1071   st->print("ESI="); print_location(st, uc->context_esi);
1072   st->print("EDI="); print_location(st, uc->context_edi);
1073 #endif // AMD64
1074 
1075   st->cr();
1076 }
1077 
1078 void os::setup_fpu() {
1079 #ifndef AMD64
1080   address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
1081   __asm__ volatile (  "fldcw (%0)" :
1082                       : "r" (fpu_cntrl) : "memory");
1083 #endif // !AMD64
1084 }
1085 
1086 #ifndef PRODUCT
1087 void os::verify_stack_alignment() {
1088 }
1089 #endif
1090 
1091 int os::extra_bang_size_in_bytes() {
1092   // JDK-8050147 requires the full cache line bang for x86.
1093   return VM_Version::L1_line_size();
1094 }