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