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 "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->on_local_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 sig == SIGBUS && thread->doing_unsafe_access()) {
212 ShouldNotCallThis();
213 }
214
215 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC
216 // kicks in and the heap gets shrunk before the field access.
217 /*if (sig == SIGSEGV || sig == SIGBUS) {
218 address addr = JNI_FastGetField::find_slowcase_pc(pc);
219 if (addr != (address)-1) {
220 stub = addr;
221 }
222 }*/
223
224 // Check to see if we caught the safepoint code in the process
225 // of write protecting the memory serialization page. It write
226 // enables the page immediately after protecting it so we can
227 // just return to retry the write.
228 if (sig == SIGSEGV &&
229 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
230 // Block current thread until permission is restored.
231 os::block_on_serialize_page_trap();
232 return true;
233 }
234 }
235
236 // signal-chaining
237 if (os::Linux::chained_handler(sig, info, ucVoid)) {
238 return true;
239 }
240
241 if (!abort_if_unrecognized) {
242 // caller wants another chance, so give it to him
243 return false;
244 }
245
246 #ifndef PRODUCT
247 if (sig == SIGSEGV) {
248 fatal("\n#"
249 "\n# /--------------------\\"
250 "\n# | segmentation fault |"
251 "\n# \\---\\ /--------------/"
252 "\n# /"
253 "\n# [-] |\\_/| "
254 "\n# (+)=C |o o|__ "
255 "\n# | | =-*-=__\\ "
256 "\n# OOO c_c_(___)");
257 }
258 #endif // !PRODUCT
259
260 char buf[64];
261
262 sprintf(buf, "caught unhandled signal %d", sig);
263
264 // Silence -Wformat-security warning for fatal()
265 PRAGMA_DIAG_PUSH
266 PRAGMA_FORMAT_NONLITERAL_IGNORED
267 fatal(buf);
268 PRAGMA_DIAG_POP
269 return true; // silence compiler warnings
270 }
271
272 void os::Linux::init_thread_fpu_state(void) {
273 // Nothing to do
274 }
275
276 int os::Linux::get_fpu_control_word() {
277 ShouldNotCallThis();
278 return -1; // silence compile warnings
279 }
280
281 void os::Linux::set_fpu_control_word(int fpu) {
282 ShouldNotCallThis();
283 }
284
285 bool os::is_allocatable(size_t bytes) {
286 #ifdef _LP64
287 return true;
288 #else
289 if (bytes < 2 * G) {
290 return true;
291 }
292
293 char* addr = reserve_memory(bytes, NULL);
294
295 if (addr != NULL) {
296 release_memory(addr, bytes);
297 }
298
299 return addr != NULL;
300 #endif // _LP64
301 }
302
303 ///////////////////////////////////////////////////////////////////////////////
304 // thread stack
305
306 size_t os::Posix::_compiler_thread_min_stack_allowed = 64 * K;
307 size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
308 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
309
310 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
311 #ifdef _LP64
312 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
313 #else
314 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
315 #endif // _LP64
316 return s;
317 }
318
319 static void current_stack_region(address *bottom, size_t *size) {
320 pthread_attr_t attr;
321 int res = pthread_getattr_np(pthread_self(), &attr);
322 if (res != 0) {
323 if (res == ENOMEM) {
324 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
325 }
326 else {
327 fatal("pthread_getattr_np failed with error = %d", res);
328 }
329 }
330
331 address stack_bottom;
332 size_t stack_bytes;
333 res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes);
334 if (res != 0) {
335 fatal("pthread_attr_getstack failed with error = %d", res);
336 }
337 address stack_top = stack_bottom + stack_bytes;
338
339 // The block of memory returned by pthread_attr_getstack() includes
340 // guard pages where present. We need to trim these off.
341 size_t page_bytes = os::Linux::page_size();
342 assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack");
343
344 size_t guard_bytes;
345 res = pthread_attr_getguardsize(&attr, &guard_bytes);
346 if (res != 0) {
347 fatal("pthread_attr_getguardsize failed with errno = %d", res);
348 }
349 int guard_pages = align_up(guard_bytes, page_bytes) / page_bytes;
350 assert(guard_bytes == guard_pages * page_bytes, "unaligned guard");
351
352 #ifdef IA64
353 // IA64 has two stacks sharing the same area of memory, a normal
354 // stack growing downwards and a register stack growing upwards.
355 // Guard pages, if present, are in the centre. This code splits
356 // the stack in two even without guard pages, though in theory
357 // there's nothing to stop us allocating more to the normal stack
358 // or more to the register stack if one or the other were found
359 // to grow faster.
360 int total_pages = align_down(stack_bytes, page_bytes) / page_bytes;
361 stack_bottom += (total_pages - guard_pages) / 2 * page_bytes;
362 #endif // IA64
363
364 stack_bottom += guard_bytes;
365
366 pthread_attr_destroy(&attr);
367
368 // The initial thread has a growable stack, and the size reported
369 // by pthread_attr_getstack is the maximum size it could possibly
370 // be given what currently mapped. This can be huge, so we cap it.
371 if (os::is_primordial_thread()) {
372 stack_bytes = stack_top - stack_bottom;
373
374 if (stack_bytes > JavaThread::stack_size_at_create())
375 stack_bytes = JavaThread::stack_size_at_create();
376
377 stack_bottom = stack_top - stack_bytes;
378 }
379
380 assert(os::current_stack_pointer() >= stack_bottom, "should do");
381 assert(os::current_stack_pointer() < stack_top, "should do");
382
383 *bottom = stack_bottom;
384 *size = stack_top - stack_bottom;
385 }
386
387 address os::current_stack_base() {
388 address bottom;
389 size_t size;
390 current_stack_region(&bottom, &size);
391 return bottom + size;
392 }
393
394 size_t os::current_stack_size() {
395 // stack size includes normal stack and HotSpot guard pages
396 address bottom;
397 size_t size;
398 current_stack_region(&bottom, &size);
399 return size;
400 }
401
402 /////////////////////////////////////////////////////////////////////////////
403 // helper functions for fatal error handler
404
405 void os::print_context(outputStream* st, const void* context) {
406 ShouldNotCallThis();
407 }
408
409 void os::print_register_info(outputStream *st, const void *context) {
410 ShouldNotCallThis();
411 }
412
413 /////////////////////////////////////////////////////////////////////////////
414 // Stubs for things that would be in linux_zero.s if it existed.
415 // You probably want to disassemble these monkeys to check they're ok.
416
417 extern "C" {
418 int SpinPause() {
419 return -1; // silence compile warnings
420 }
421
422
423 void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) {
424 if (from > to) {
425 jshort *end = from + count;
426 while (from < end)
427 *(to++) = *(from++);
428 }
429 else if (from < to) {
430 jshort *end = from;
431 from += count - 1;
432 to += count - 1;
433 while (from >= end)
434 *(to--) = *(from--);
435 }
436 }
437 void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) {
438 if (from > to) {
439 jint *end = from + count;
440 while (from < end)
441 *(to++) = *(from++);
442 }
443 else if (from < to) {
444 jint *end = from;
445 from += count - 1;
446 to += count - 1;
447 while (from >= end)
448 *(to--) = *(from--);
449 }
450 }
451 void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) {
452 if (from > to) {
453 jlong *end = from + count;
454 while (from < end)
455 os::atomic_copy64(from++, to++);
456 }
457 else if (from < to) {
458 jlong *end = from;
459 from += count - 1;
460 to += count - 1;
461 while (from >= end)
462 os::atomic_copy64(from--, to--);
463 }
464 }
465
466 void _Copy_arrayof_conjoint_bytes(HeapWord* from,
467 HeapWord* to,
468 size_t count) {
469 memmove(to, from, count);
470 }
471 void _Copy_arrayof_conjoint_jshorts(HeapWord* from,
472 HeapWord* to,
473 size_t count) {
474 memmove(to, from, count * 2);
475 }
476 void _Copy_arrayof_conjoint_jints(HeapWord* from,
477 HeapWord* to,
478 size_t count) {
479 memmove(to, from, count * 4);
480 }
481 void _Copy_arrayof_conjoint_jlongs(HeapWord* from,
482 HeapWord* to,
483 size_t count) {
484 memmove(to, from, count * 8);
485 }
486 };
487
488 /////////////////////////////////////////////////////////////////////////////
489 // Implementations of atomic operations not supported by processors.
490 // -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html
491
492 #ifndef _LP64
493 extern "C" {
494 long long unsigned int __sync_val_compare_and_swap_8(
495 volatile void *ptr,
496 long long unsigned int oldval,
497 long long unsigned int newval) {
498 ShouldNotCallThis();
499 }
500 };
501 #endif // !_LP64
502
503 #ifndef PRODUCT
504 void os::verify_stack_alignment() {
505 }
506 #endif
507
508 int os::extra_bang_size_in_bytes() {
509 // Zero does not require an additional stack banging.
510 return 0;
511 }