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::Posix::_compiler_thread_min_stack_allowed = 64 * K;
311 size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
312 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
313
314 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
315 #ifdef _LP64
316 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
317 #else
318 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
319 #endif // _LP64
320 return s;
321 }
322
323 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
324 // Only enable glibc guard pages for non-Java threads
325 // (Java threads have HotSpot guard pages)
326 return (thr_type == java_thread ? 0 : page_size());
327 }
328
329 static void current_stack_region(address *bottom, size_t *size) {
330 pthread_attr_t attr;
331 int res = pthread_getattr_np(pthread_self(), &attr);
332 if (res != 0) {
333 if (res == ENOMEM) {
334 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
335 }
336 else {
337 fatal("pthread_getattr_np failed with errno = %d", res);
338 }
339 }
340
341 address stack_bottom;
342 size_t stack_bytes;
343 res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes);
344 if (res != 0) {
345 fatal("pthread_attr_getstack failed with errno = %d", res);
346 }
347 address stack_top = stack_bottom + stack_bytes;
348
349 // The block of memory returned by pthread_attr_getstack() includes
350 // guard pages where present. We need to trim these off.
351 size_t page_bytes = os::Linux::page_size();
352 assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack");
353
354 size_t guard_bytes;
355 res = pthread_attr_getguardsize(&attr, &guard_bytes);
356 if (res != 0) {
357 fatal("pthread_attr_getguardsize failed with errno = %d", res);
358 }
359 int guard_pages = align_size_up(guard_bytes, page_bytes) / page_bytes;
360 assert(guard_bytes == guard_pages * page_bytes, "unaligned guard");
361
362 #ifdef IA64
363 // IA64 has two stacks sharing the same area of memory, a normal
364 // stack growing downwards and a register stack growing upwards.
365 // Guard pages, if present, are in the centre. This code splits
366 // the stack in two even without guard pages, though in theory
367 // there's nothing to stop us allocating more to the normal stack
368 // or more to the register stack if one or the other were found
369 // to grow faster.
370 int total_pages = align_size_down(stack_bytes, page_bytes) / page_bytes;
371 stack_bottom += (total_pages - guard_pages) / 2 * page_bytes;
372 #endif // IA64
373
374 stack_bottom += guard_bytes;
375
376 pthread_attr_destroy(&attr);
377
378 // The initial thread has a growable stack, and the size reported
379 // by pthread_attr_getstack is the maximum size it could possibly
380 // be given what currently mapped. This can be huge, so we cap it.
381 if (os::Linux::is_initial_thread()) {
382 stack_bytes = stack_top - stack_bottom;
383
384 if (stack_bytes > JavaThread::stack_size_at_create())
385 stack_bytes = JavaThread::stack_size_at_create();
386
387 stack_bottom = stack_top - stack_bytes;
388 }
389
390 assert(os::current_stack_pointer() >= stack_bottom, "should do");
391 assert(os::current_stack_pointer() < stack_top, "should do");
392
393 *bottom = stack_bottom;
394 *size = stack_top - stack_bottom;
395 }
396
397 address os::current_stack_base() {
398 address bottom;
399 size_t size;
400 current_stack_region(&bottom, &size);
401 return bottom + size;
402 }
403
404 size_t os::current_stack_size() {
405 // stack size includes normal stack and HotSpot guard pages
406 address bottom;
407 size_t size;
408 current_stack_region(&bottom, &size);
409 return size;
410 }
411
412 /////////////////////////////////////////////////////////////////////////////
413 // helper functions for fatal error handler
414
415 void os::print_context(outputStream* st, const void* context) {
416 ShouldNotCallThis();
417 }
418
419 void os::print_register_info(outputStream *st, const void *context) {
420 ShouldNotCallThis();
421 }
422
423 /////////////////////////////////////////////////////////////////////////////
424 // Stubs for things that would be in linux_zero.s if it existed.
425 // You probably want to disassemble these monkeys to check they're ok.
426
427 extern "C" {
428 int SpinPause() {
429 return -1; // silence compile warnings
430 }
431
432
433 void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) {
434 if (from > to) {
435 jshort *end = from + count;
436 while (from < end)
437 *(to++) = *(from++);
438 }
439 else if (from < to) {
440 jshort *end = from;
441 from += count - 1;
442 to += count - 1;
443 while (from >= end)
444 *(to--) = *(from--);
445 }
446 }
447 void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) {
448 if (from > to) {
449 jint *end = from + count;
450 while (from < end)
451 *(to++) = *(from++);
452 }
453 else if (from < to) {
454 jint *end = from;
455 from += count - 1;
456 to += count - 1;
457 while (from >= end)
458 *(to--) = *(from--);
459 }
460 }
461 void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) {
462 if (from > to) {
463 jlong *end = from + count;
464 while (from < end)
465 os::atomic_copy64(from++, to++);
466 }
467 else if (from < to) {
468 jlong *end = from;
469 from += count - 1;
470 to += count - 1;
471 while (from >= end)
472 os::atomic_copy64(from--, to--);
473 }
474 }
475
476 void _Copy_arrayof_conjoint_bytes(HeapWord* from,
477 HeapWord* to,
478 size_t count) {
479 memmove(to, from, count);
480 }
481 void _Copy_arrayof_conjoint_jshorts(HeapWord* from,
482 HeapWord* to,
483 size_t count) {
484 memmove(to, from, count * 2);
485 }
486 void _Copy_arrayof_conjoint_jints(HeapWord* from,
487 HeapWord* to,
488 size_t count) {
489 memmove(to, from, count * 4);
490 }
491 void _Copy_arrayof_conjoint_jlongs(HeapWord* from,
492 HeapWord* to,
493 size_t count) {
494 memmove(to, from, count * 8);
495 }
496 };
497
498 /////////////////////////////////////////////////////////////////////////////
499 // Implementations of atomic operations not supported by processors.
500 // -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html
501
502 #ifndef _LP64
503 extern "C" {
504 long long unsigned int __sync_val_compare_and_swap_8(
505 volatile void *ptr,
506 long long unsigned int oldval,
507 long long unsigned int newval) {
508 ShouldNotCallThis();
509 }
510 };
511 #endif // !_LP64
512
513 #ifndef PRODUCT
514 void os::verify_stack_alignment() {
515 }
516 #endif
517
518 int os::extra_bang_size_in_bytes() {
519 // Zero does not require an additional stack banging.
520 return 0;
521 }