1 /*
2 * Copyright (c) 2003, 2019, 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 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(jshort* from, jshort* to, size_t count) {
414 if (from > to) {
415 jshort *end = from + count;
416 while (from < end)
417 *(to++) = *(from++);
418 }
419 else if (from < to) {
420 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(jint* from, jint* to, size_t count) {
428 if (from > to) {
429 jint *end = from + count;
430 while (from < end)
431 *(to++) = *(from++);
432 }
433 else if (from < to) {
434 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(jlong* from, jlong* to, size_t count) {
442 if (from > to) {
443 jlong *end = from + count;
444 while (from < end)
445 os::atomic_copy64(from++, to++);
446 }
447 else if (from < to) {
448 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(HeapWord* from,
457 HeapWord* to,
458 size_t count) {
459 memmove(to, from, count);
460 }
461 void _Copy_arrayof_conjoint_jshorts(HeapWord* from,
462 HeapWord* to,
463 size_t count) {
464 memmove(to, from, count * 2);
465 }
466 void _Copy_arrayof_conjoint_jints(HeapWord* from,
467 HeapWord* to,
468 size_t count) {
469 memmove(to, from, count * 4);
470 }
471 void _Copy_arrayof_conjoint_jlongs(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 }