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