1 /* 2 * Copyright (c) 2003, 2020, 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 "jvm.h" 28 #include "assembler_zero.inline.hpp" 29 #include "classfile/classLoader.hpp" 30 #include "classfile/systemDictionary.hpp" 31 #include "classfile/vmSymbols.hpp" 32 #include "code/icBuffer.hpp" 33 #include "code/vtableStubs.hpp" 34 #include "interpreter/interpreter.hpp" 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_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/sharedRuntime.hpp" 49 #include "runtime/stubRoutines.hpp" 50 #include "runtime/thread.inline.hpp" 51 #include "runtime/timer.hpp" 52 #include "utilities/align.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 address os::Linux::ucontext_get_pc(const ucontext_t* uc) { 100 ShouldNotCallThis(); 101 return NULL; // silence compile warnings 102 } 103 104 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) { 105 ShouldNotCallThis(); 106 } 107 108 ExtendedPC os::fetch_frame_from_context(const void* ucVoid, 109 intptr_t** ret_sp, 110 intptr_t** ret_fp) { 111 ShouldNotCallThis(); 112 return NULL; // silence compile warnings 113 } 114 115 frame os::fetch_frame_from_context(const void* ucVoid) { 116 ShouldNotCallThis(); 117 return frame(NULL, NULL); // silence compile warnings 118 } 119 120 extern "C" JNIEXPORT int 121 JVM_handle_linux_signal(int sig, 122 siginfo_t* info, 123 void* ucVoid, 124 int abort_if_unrecognized) { 125 ucontext_t* uc = (ucontext_t*) ucVoid; 126 127 Thread* t = Thread::current_or_null_safe(); 128 129 SignalHandlerMark shm(t); 130 131 // handle SafeFetch faults 132 if (sig == SIGSEGV || sig == SIGBUS) { 133 sigjmp_buf* const pjb = get_jmp_buf_for_continuation(); 134 if (pjb) { 135 siglongjmp(*pjb, 1); 136 } 137 } 138 139 // Note: it's not uncommon that JNI code uses signal/sigset to 140 // install then restore certain signal handler (e.g. to temporarily 141 // block SIGPIPE, or have a SIGILL handler when detecting CPU 142 // type). When that happens, JVM_handle_linux_signal() might be 143 // invoked with junk info/ucVoid. To avoid unnecessary crash when 144 // libjsig is not preloaded, try handle signals that do not require 145 // siginfo/ucontext first. 146 147 if (sig == SIGPIPE || sig == SIGXFSZ) { 148 // allow chained handler to go first 149 if (os::Linux::chained_handler(sig, info, ucVoid)) { 150 return true; 151 } else { 152 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219 153 return true; 154 } 155 } 156 157 JavaThread* thread = NULL; 158 VMThread* vmthread = NULL; 159 if (os::Linux::signal_handlers_are_installed) { 160 if (t != NULL ){ 161 if(t->is_Java_thread()) { 162 thread = (JavaThread*)t; 163 } 164 else if(t->is_VM_thread()){ 165 vmthread = (VMThread *)t; 166 } 167 } 168 } 169 170 if (info != NULL && thread != NULL) { 171 // Handle ALL stack overflow variations here 172 if (sig == SIGSEGV) { 173 address addr = (address) info->si_addr; 174 175 // check if fault address is within thread stack 176 if (thread->is_in_full_stack(addr)) { 177 // stack overflow 178 if (thread->in_stack_yellow_reserved_zone(addr)) { 179 thread->disable_stack_yellow_reserved_zone(); 180 ShouldNotCallThis(); 181 } 182 else if (thread->in_stack_red_zone(addr)) { 183 thread->disable_stack_red_zone(); 184 ShouldNotCallThis(); 185 } 186 else { 187 // Accessing stack address below sp may cause SEGV if 188 // current thread has MAP_GROWSDOWN stack. This should 189 // only happen when current thread was created by user 190 // code with MAP_GROWSDOWN flag and then attached to VM. 191 // See notes in os_linux.cpp. 192 if (thread->osthread()->expanding_stack() == 0) { 193 thread->osthread()->set_expanding_stack(); 194 if (os::Linux::manually_expand_stack(thread, addr)) { 195 thread->osthread()->clear_expanding_stack(); 196 return true; 197 } 198 thread->osthread()->clear_expanding_stack(); 199 } 200 else { 201 fatal("recursive segv. expanding stack."); 202 } 203 } 204 } 205 } 206 207 /*if (thread->thread_state() == _thread_in_Java) { 208 ShouldNotCallThis(); 209 } 210 else*/ if ((thread->thread_state() == _thread_in_vm || 211 thread->thread_state() == _thread_in_native) && 212 sig == SIGBUS && thread->doing_unsafe_access()) { 213 ShouldNotCallThis(); 214 } 215 216 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC 217 // kicks in and the heap gets shrunk before the field access. 218 /*if (sig == SIGSEGV || sig == SIGBUS) { 219 address addr = JNI_FastGetField::find_slowcase_pc(pc); 220 if (addr != (address)-1) { 221 stub = addr; 222 } 223 }*/ 224 } 225 226 // signal-chaining 227 if (os::Linux::chained_handler(sig, info, ucVoid)) { 228 return true; 229 } 230 231 if (!abort_if_unrecognized) { 232 // caller wants another chance, so give it to him 233 return false; 234 } 235 236 #ifndef PRODUCT 237 if (sig == SIGSEGV) { 238 fatal("\n#" 239 "\n# /--------------------\\" 240 "\n# | segmentation fault |" 241 "\n# \\---\\ /--------------/" 242 "\n# /" 243 "\n# [-] |\\_/| " 244 "\n# (+)=C |o o|__ " 245 "\n# | | =-*-=__\\ " 246 "\n# OOO c_c_(___)"); 247 } 248 #endif // !PRODUCT 249 250 char buf[64]; 251 252 sprintf(buf, "caught unhandled signal %d", sig); 253 254 // Silence -Wformat-security warning for fatal() 255 PRAGMA_DIAG_PUSH 256 PRAGMA_FORMAT_NONLITERAL_IGNORED 257 fatal(buf); 258 PRAGMA_DIAG_POP 259 return true; // silence compiler warnings 260 } 261 262 void os::Linux::init_thread_fpu_state(void) { 263 // Nothing to do 264 } 265 266 int os::Linux::get_fpu_control_word() { 267 ShouldNotCallThis(); 268 return -1; // silence compile warnings 269 } 270 271 void os::Linux::set_fpu_control_word(int fpu) { 272 ShouldNotCallThis(); 273 } 274 275 bool os::is_allocatable(size_t bytes) { 276 #ifdef _LP64 277 return true; 278 #else 279 if (bytes < 2 * G) { 280 return true; 281 } 282 283 char* addr = reserve_memory(bytes, NULL); 284 285 if (addr != NULL) { 286 release_memory(addr, bytes); 287 } 288 289 return addr != NULL; 290 #endif // _LP64 291 } 292 293 /////////////////////////////////////////////////////////////////////////////// 294 // thread stack 295 296 size_t os::Posix::_compiler_thread_min_stack_allowed = 64 * K; 297 size_t os::Posix::_java_thread_min_stack_allowed = 64 * K; 298 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K; 299 300 size_t os::Posix::default_stack_size(os::ThreadType thr_type) { 301 #ifdef _LP64 302 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M); 303 #else 304 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K); 305 #endif // _LP64 306 return s; 307 } 308 309 static void current_stack_region(address *bottom, size_t *size) { 310 pthread_attr_t attr; 311 int res = pthread_getattr_np(pthread_self(), &attr); 312 if (res != 0) { 313 if (res == ENOMEM) { 314 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 315 } 316 else { 317 fatal("pthread_getattr_np failed with error = %d", res); 318 } 319 } 320 321 address stack_bottom; 322 size_t stack_bytes; 323 res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes); 324 if (res != 0) { 325 fatal("pthread_attr_getstack failed with error = %d", res); 326 } 327 address stack_top = stack_bottom + stack_bytes; 328 329 // The block of memory returned by pthread_attr_getstack() includes 330 // guard pages where present. We need to trim these off. 331 size_t page_bytes = os::Linux::page_size(); 332 assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack"); 333 334 size_t guard_bytes; 335 res = pthread_attr_getguardsize(&attr, &guard_bytes); 336 if (res != 0) { 337 fatal("pthread_attr_getguardsize failed with errno = %d", res); 338 } 339 int guard_pages = align_up(guard_bytes, page_bytes) / page_bytes; 340 assert(guard_bytes == guard_pages * page_bytes, "unaligned guard"); 341 342 #ifdef IA64 343 // IA64 has two stacks sharing the same area of memory, a normal 344 // stack growing downwards and a register stack growing upwards. 345 // Guard pages, if present, are in the centre. This code splits 346 // the stack in two even without guard pages, though in theory 347 // there's nothing to stop us allocating more to the normal stack 348 // or more to the register stack if one or the other were found 349 // to grow faster. 350 int total_pages = align_down(stack_bytes, page_bytes) / page_bytes; 351 stack_bottom += (total_pages - guard_pages) / 2 * page_bytes; 352 #endif // IA64 353 354 stack_bottom += guard_bytes; 355 356 pthread_attr_destroy(&attr); 357 358 // The initial thread has a growable stack, and the size reported 359 // by pthread_attr_getstack is the maximum size it could possibly 360 // be given what currently mapped. This can be huge, so we cap it. 361 if (os::is_primordial_thread()) { 362 stack_bytes = stack_top - stack_bottom; 363 364 if (stack_bytes > JavaThread::stack_size_at_create()) 365 stack_bytes = JavaThread::stack_size_at_create(); 366 367 stack_bottom = stack_top - stack_bytes; 368 } 369 370 assert(os::current_stack_pointer() >= stack_bottom, "should do"); 371 assert(os::current_stack_pointer() < stack_top, "should do"); 372 373 *bottom = stack_bottom; 374 *size = stack_top - stack_bottom; 375 } 376 377 address os::current_stack_base() { 378 address bottom; 379 size_t size; 380 current_stack_region(&bottom, &size); 381 return bottom + size; 382 } 383 384 size_t os::current_stack_size() { 385 // stack size includes normal stack and HotSpot guard pages 386 address bottom; 387 size_t size; 388 current_stack_region(&bottom, &size); 389 return size; 390 } 391 392 ///////////////////////////////////////////////////////////////////////////// 393 // helper functions for fatal error handler 394 395 void os::print_context(outputStream* st, const void* context) { 396 ShouldNotCallThis(); 397 } 398 399 void os::print_register_info(outputStream *st, const void *context) { 400 ShouldNotCallThis(); 401 } 402 403 ///////////////////////////////////////////////////////////////////////////// 404 // Stubs for things that would be in linux_zero.s if it existed. 405 // You probably want to disassemble these monkeys to check they're ok. 406 407 extern "C" { 408 int SpinPause() { 409 return -1; // silence compile warnings 410 } 411 412 413 void _Copy_conjoint_jshorts_atomic(const jshort* from, jshort* to, size_t count) { 414 if (from > to) { 415 const jshort *end = from + count; 416 while (from < end) 417 *(to++) = *(from++); 418 } 419 else if (from < to) { 420 const jshort *end = from; 421 from += count - 1; 422 to += count - 1; 423 while (from >= end) 424 *(to--) = *(from--); 425 } 426 } 427 void _Copy_conjoint_jints_atomic(const jint* from, jint* to, size_t count) { 428 if (from > to) { 429 const jint *end = from + count; 430 while (from < end) 431 *(to++) = *(from++); 432 } 433 else if (from < to) { 434 const jint *end = from; 435 from += count - 1; 436 to += count - 1; 437 while (from >= end) 438 *(to--) = *(from--); 439 } 440 } 441 void _Copy_conjoint_jlongs_atomic(const jlong* from, jlong* to, size_t count) { 442 if (from > to) { 443 const jlong *end = from + count; 444 while (from < end) 445 os::atomic_copy64(from++, to++); 446 } 447 else if (from < to) { 448 const jlong *end = from; 449 from += count - 1; 450 to += count - 1; 451 while (from >= end) 452 os::atomic_copy64(from--, to--); 453 } 454 } 455 456 void _Copy_arrayof_conjoint_bytes(const HeapWord* from, 457 HeapWord* to, 458 size_t count) { 459 memmove(to, from, count); 460 } 461 void _Copy_arrayof_conjoint_jshorts(const HeapWord* from, 462 HeapWord* to, 463 size_t count) { 464 memmove(to, from, count * 2); 465 } 466 void _Copy_arrayof_conjoint_jints(const HeapWord* from, 467 HeapWord* to, 468 size_t count) { 469 memmove(to, from, count * 4); 470 } 471 void _Copy_arrayof_conjoint_jlongs(const HeapWord* from, 472 HeapWord* to, 473 size_t count) { 474 memmove(to, from, count * 8); 475 } 476 }; 477 478 ///////////////////////////////////////////////////////////////////////////// 479 // Implementations of atomic operations not supported by processors. 480 // -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html 481 482 #ifndef _LP64 483 extern "C" { 484 long long unsigned int __sync_val_compare_and_swap_8( 485 volatile void *ptr, 486 long long unsigned int oldval, 487 long long unsigned int newval) { 488 ShouldNotCallThis(); 489 } 490 }; 491 #endif // !_LP64 492 493 #ifndef PRODUCT 494 void os::verify_stack_alignment() { 495 } 496 #endif 497 498 int os::extra_bang_size_in_bytes() { 499 // Zero does not require an additional stack banging. 500 return 0; 501 }