1 /* 2 * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved. 3 * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 * 24 */ 25 26 // no precompiled headers 27 #include "assembler_zero.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 "jvm_linux.h" 35 #include "memory/allocation.inline.hpp" 36 #include "nativeInst_zero.hpp" 37 #include "os_share_linux.hpp" 38 #include "prims/jniFastGetField.hpp" 39 #include "prims/jvm.h" 40 #include "prims/jvm_misc.hpp" 41 #include "runtime/arguments.hpp" 42 #include "runtime/extendedPC.hpp" 43 #include "runtime/frame.inline.hpp" 44 #include "runtime/interfaceSupport.hpp" 45 #include "runtime/java.hpp" 46 #include "runtime/javaCalls.hpp" 47 #include "runtime/mutexLocker.hpp" 48 #include "runtime/osThread.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/events.hpp" 54 #include "utilities/vmError.hpp" 55 56 // See stubGenerator_zero.cpp 57 #include <setjmp.h> 58 extern sigjmp_buf* get_jmp_buf_for_continuation(); 59 60 address os::current_stack_pointer() { 61 // return the address of the current function 62 return (address)__builtin_frame_address(0); 63 } 64 65 frame os::get_sender_for_C_frame(frame* fr) { 66 ShouldNotCallThis(); 67 return frame(NULL, NULL); // silence compile warning. 68 } 69 70 frame os::current_frame() { 71 // The only thing that calls this is the stack printing code in 72 // VMError::report: 73 // - Step 110 (printing stack bounds) uses the sp in the frame 74 // to determine the amount of free space on the stack. We 75 // set the sp to a close approximation of the real value in 76 // order to allow this step to complete. 77 // - Step 120 (printing native stack) tries to walk the stack. 78 // The frame we create has a NULL pc, which is ignored as an 79 // invalid frame. 80 frame dummy = frame(); 81 dummy.set_sp((intptr_t *) current_stack_pointer()); 82 return dummy; 83 } 84 85 char* os::non_memory_address_word() { 86 // Must never look like an address returned by reserve_memory, 87 // even in its subfields (as defined by the CPU immediate fields, 88 // if the CPU splits constants across multiple instructions). 89 #ifdef SPARC 90 // On SPARC, 0 != %hi(any real address), because there is no 91 // allocation in the first 1Kb of the virtual address space. 92 return (char *) 0; 93 #else 94 // This is the value for x86; works pretty well for PPC too. 95 return (char *) -1; 96 #endif // SPARC 97 } 98 99 void os::initialize_thread(Thread * thr){ 100 // Nothing to do. 101 } 102 103 address os::Linux::ucontext_get_pc(const ucontext_t* uc) { 104 ShouldNotCallThis(); 105 return NULL; // silence compile warnings 106 } 107 108 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) { 109 ShouldNotCallThis(); 110 } 111 112 ExtendedPC os::fetch_frame_from_context(const void* ucVoid, 113 intptr_t** ret_sp, 114 intptr_t** ret_fp) { 115 ShouldNotCallThis(); 116 return NULL; // silence compile warnings 117 } 118 119 frame os::fetch_frame_from_context(const void* ucVoid) { 120 ShouldNotCallThis(); 121 return frame(NULL, NULL); // silence compile warnings 122 } 123 124 extern "C" JNIEXPORT int 125 JVM_handle_linux_signal(int sig, 126 siginfo_t* info, 127 void* ucVoid, 128 int abort_if_unrecognized) { 129 ucontext_t* uc = (ucontext_t*) ucVoid; 130 131 Thread* t = Thread::current_or_null_safe(); 132 133 SignalHandlerMark shm(t); 134 135 // handle SafeFetch faults 136 if (sig == SIGSEGV || sig == SIGBUS) { 137 sigjmp_buf* const pjb = get_jmp_buf_for_continuation(); 138 if (pjb) { 139 siglongjmp(*pjb, 1); 140 } 141 } 142 143 // Note: it's not uncommon that JNI code uses signal/sigset to 144 // install then restore certain signal handler (e.g. to temporarily 145 // block SIGPIPE, or have a SIGILL handler when detecting CPU 146 // type). When that happens, JVM_handle_linux_signal() might be 147 // invoked with junk info/ucVoid. To avoid unnecessary crash when 148 // libjsig is not preloaded, try handle signals that do not require 149 // siginfo/ucontext first. 150 151 if (sig == SIGPIPE || sig == SIGXFSZ) { 152 // allow chained handler to go first 153 if (os::Linux::chained_handler(sig, info, ucVoid)) { 154 return true; 155 } else { 156 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219 157 return true; 158 } 159 } 160 161 JavaThread* thread = NULL; 162 VMThread* vmthread = NULL; 163 if (os::Linux::signal_handlers_are_installed) { 164 if (t != NULL ){ 165 if(t->is_Java_thread()) { 166 thread = (JavaThread*)t; 167 } 168 else if(t->is_VM_thread()){ 169 vmthread = (VMThread *)t; 170 } 171 } 172 } 173 174 if (info != NULL && thread != NULL) { 175 // Handle ALL stack overflow variations here 176 if (sig == SIGSEGV) { 177 address addr = (address) info->si_addr; 178 179 // check if fault address is within thread stack 180 if (thread->on_local_stack(addr)) { 181 // stack overflow 182 if (thread->in_stack_yellow_reserved_zone(addr)) { 183 thread->disable_stack_yellow_reserved_zone(); 184 ShouldNotCallThis(); 185 } 186 else if (thread->in_stack_red_zone(addr)) { 187 thread->disable_stack_red_zone(); 188 ShouldNotCallThis(); 189 } 190 else { 191 // Accessing stack address below sp may cause SEGV if 192 // current thread has MAP_GROWSDOWN stack. This should 193 // only happen when current thread was created by user 194 // code with MAP_GROWSDOWN flag and then attached to VM. 195 // See notes in os_linux.cpp. 196 if (thread->osthread()->expanding_stack() == 0) { 197 thread->osthread()->set_expanding_stack(); 198 if (os::Linux::manually_expand_stack(thread, addr)) { 199 thread->osthread()->clear_expanding_stack(); 200 return true; 201 } 202 thread->osthread()->clear_expanding_stack(); 203 } 204 else { 205 fatal("recursive segv. expanding stack."); 206 } 207 } 208 } 209 } 210 211 /*if (thread->thread_state() == _thread_in_Java) { 212 ShouldNotCallThis(); 213 } 214 else*/ if (thread->thread_state() == _thread_in_vm && 215 sig == SIGBUS && thread->doing_unsafe_access()) { 216 ShouldNotCallThis(); 217 } 218 219 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC 220 // kicks in and the heap gets shrunk before the field access. 221 /*if (sig == SIGSEGV || sig == SIGBUS) { 222 address addr = JNI_FastGetField::find_slowcase_pc(pc); 223 if (addr != (address)-1) { 224 stub = addr; 225 } 226 }*/ 227 228 // Check to see if we caught the safepoint code in the process 229 // of write protecting the memory serialization page. It write 230 // enables the page immediately after protecting it so we can 231 // just return to retry the write. 232 if (sig == SIGSEGV && 233 os::is_memory_serialize_page(thread, (address) info->si_addr)) { 234 // Block current thread until permission is restored. 235 os::block_on_serialize_page_trap(); 236 return true; 237 } 238 } 239 240 // signal-chaining 241 if (os::Linux::chained_handler(sig, info, ucVoid)) { 242 return true; 243 } 244 245 if (!abort_if_unrecognized) { 246 // caller wants another chance, so give it to him 247 return false; 248 } 249 250 #ifndef PRODUCT 251 if (sig == SIGSEGV) { 252 fatal("\n#" 253 "\n# /--------------------\\" 254 "\n# | segmentation fault |" 255 "\n# \\---\\ /--------------/" 256 "\n# /" 257 "\n# [-] |\\_/| " 258 "\n# (+)=C |o o|__ " 259 "\n# | | =-*-=__\\ " 260 "\n# OOO c_c_(___)"); 261 } 262 #endif // !PRODUCT 263 264 char buf[64]; 265 266 sprintf(buf, "caught unhandled signal %d", sig); 267 268 // Silence -Wformat-security warning for fatal() 269 PRAGMA_DIAG_PUSH 270 PRAGMA_FORMAT_NONLITERAL_IGNORED 271 fatal(buf); 272 PRAGMA_DIAG_POP 273 return true; // silence compiler warnings 274 } 275 276 void os::Linux::init_thread_fpu_state(void) { 277 // Nothing to do 278 } 279 280 int os::Linux::get_fpu_control_word() { 281 ShouldNotCallThis(); 282 return -1; // silence compile warnings 283 } 284 285 void os::Linux::set_fpu_control_word(int fpu) { 286 ShouldNotCallThis(); 287 } 288 289 bool os::is_allocatable(size_t bytes) { 290 #ifdef _LP64 291 return true; 292 #else 293 if (bytes < 2 * G) { 294 return true; 295 } 296 297 char* addr = reserve_memory(bytes, NULL); 298 299 if (addr != NULL) { 300 release_memory(addr, bytes); 301 } 302 303 return addr != NULL; 304 #endif // _LP64 305 } 306 307 /////////////////////////////////////////////////////////////////////////////// 308 // thread stack 309 310 size_t os::Linux::min_stack_allowed = 64 * K; 311 312 size_t os::Linux::default_stack_size(os::ThreadType thr_type) { 313 #ifdef _LP64 314 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M); 315 #else 316 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K); 317 #endif // _LP64 318 return s; 319 } 320 321 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 322 // Only enable glibc guard pages for non-Java threads 323 // (Java threads have HotSpot guard pages) 324 return (thr_type == java_thread ? 0 : page_size()); 325 } 326 327 static void current_stack_region(address *bottom, size_t *size) { 328 pthread_attr_t attr; 329 int res = pthread_getattr_np(pthread_self(), &attr); 330 if (res != 0) { 331 if (res == ENOMEM) { 332 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 333 } 334 else { 335 fatal("pthread_getattr_np failed with errno = %d", res); 336 } 337 } 338 339 address stack_bottom; 340 size_t stack_bytes; 341 res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes); 342 if (res != 0) { 343 fatal("pthread_attr_getstack failed with errno = %d", res); 344 } 345 address stack_top = stack_bottom + stack_bytes; 346 347 // The block of memory returned by pthread_attr_getstack() includes 348 // guard pages where present. We need to trim these off. 349 size_t page_bytes = os::Linux::page_size(); 350 assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack"); 351 352 size_t guard_bytes; 353 res = pthread_attr_getguardsize(&attr, &guard_bytes); 354 if (res != 0) { 355 fatal("pthread_attr_getguardsize failed with errno = %d", res); 356 } 357 int guard_pages = align_size_up(guard_bytes, page_bytes) / page_bytes; 358 assert(guard_bytes == guard_pages * page_bytes, "unaligned guard"); 359 360 #ifdef IA64 361 // IA64 has two stacks sharing the same area of memory, a normal 362 // stack growing downwards and a register stack growing upwards. 363 // Guard pages, if present, are in the centre. This code splits 364 // the stack in two even without guard pages, though in theory 365 // there's nothing to stop us allocating more to the normal stack 366 // or more to the register stack if one or the other were found 367 // to grow faster. 368 int total_pages = align_size_down(stack_bytes, page_bytes) / page_bytes; 369 stack_bottom += (total_pages - guard_pages) / 2 * page_bytes; 370 #endif // IA64 371 372 stack_bottom += guard_bytes; 373 374 pthread_attr_destroy(&attr); 375 376 // The initial thread has a growable stack, and the size reported 377 // by pthread_attr_getstack is the maximum size it could possibly 378 // be given what currently mapped. This can be huge, so we cap it. 379 if (os::Linux::is_initial_thread()) { 380 stack_bytes = stack_top - stack_bottom; 381 382 if (stack_bytes > JavaThread::stack_size_at_create()) 383 stack_bytes = JavaThread::stack_size_at_create(); 384 385 stack_bottom = stack_top - stack_bytes; 386 } 387 388 assert(os::current_stack_pointer() >= stack_bottom, "should do"); 389 assert(os::current_stack_pointer() < stack_top, "should do"); 390 391 *bottom = stack_bottom; 392 *size = stack_top - stack_bottom; 393 } 394 395 address os::current_stack_base() { 396 address bottom; 397 size_t size; 398 current_stack_region(&bottom, &size); 399 return bottom + size; 400 } 401 402 size_t os::current_stack_size() { 403 // stack size includes normal stack and HotSpot guard pages 404 address bottom; 405 size_t size; 406 current_stack_region(&bottom, &size); 407 return size; 408 } 409 410 ///////////////////////////////////////////////////////////////////////////// 411 // helper functions for fatal error handler 412 413 void os::print_context(outputStream* st, const void* context) { 414 ShouldNotCallThis(); 415 } 416 417 void os::print_register_info(outputStream *st, const void *context) { 418 ShouldNotCallThis(); 419 } 420 421 ///////////////////////////////////////////////////////////////////////////// 422 // Stubs for things that would be in linux_zero.s if it existed. 423 // You probably want to disassemble these monkeys to check they're ok. 424 425 extern "C" { 426 int SpinPause() { 427 return -1; // silence compile warnings 428 } 429 430 431 void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) { 432 if (from > to) { 433 jshort *end = from + count; 434 while (from < end) 435 *(to++) = *(from++); 436 } 437 else if (from < to) { 438 jshort *end = from; 439 from += count - 1; 440 to += count - 1; 441 while (from >= end) 442 *(to--) = *(from--); 443 } 444 } 445 void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) { 446 if (from > to) { 447 jint *end = from + count; 448 while (from < end) 449 *(to++) = *(from++); 450 } 451 else if (from < to) { 452 jint *end = from; 453 from += count - 1; 454 to += count - 1; 455 while (from >= end) 456 *(to--) = *(from--); 457 } 458 } 459 void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) { 460 if (from > to) { 461 jlong *end = from + count; 462 while (from < end) 463 os::atomic_copy64(from++, to++); 464 } 465 else if (from < to) { 466 jlong *end = from; 467 from += count - 1; 468 to += count - 1; 469 while (from >= end) 470 os::atomic_copy64(from--, to--); 471 } 472 } 473 474 void _Copy_arrayof_conjoint_bytes(HeapWord* from, 475 HeapWord* to, 476 size_t count) { 477 memmove(to, from, count); 478 } 479 void _Copy_arrayof_conjoint_jshorts(HeapWord* from, 480 HeapWord* to, 481 size_t count) { 482 memmove(to, from, count * 2); 483 } 484 void _Copy_arrayof_conjoint_jints(HeapWord* from, 485 HeapWord* to, 486 size_t count) { 487 memmove(to, from, count * 4); 488 } 489 void _Copy_arrayof_conjoint_jlongs(HeapWord* from, 490 HeapWord* to, 491 size_t count) { 492 memmove(to, from, count * 8); 493 } 494 }; 495 496 ///////////////////////////////////////////////////////////////////////////// 497 // Implementations of atomic operations not supported by processors. 498 // -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html 499 500 #ifndef _LP64 501 extern "C" { 502 long long unsigned int __sync_val_compare_and_swap_8( 503 volatile void *ptr, 504 long long unsigned int oldval, 505 long long unsigned int newval) { 506 ShouldNotCallThis(); 507 } 508 }; 509 #endif // !_LP64 510 511 #ifndef PRODUCT 512 void os::verify_stack_alignment() { 513 } 514 #endif 515 516 int os::extra_bang_size_in_bytes() { 517 // Zero does not require an additional stack banging. 518 return 0; 519 }