1 /*
2 * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // no precompiled headers
26 #include "jvm.h"
27 #include "asm/macroAssembler.hpp"
28 #include "classfile/classLoader.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/codeCache.hpp"
32 #include "code/icBuffer.hpp"
33 #include "code/vtableStubs.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "logging/log.hpp"
36 #include "memory/allocation.inline.hpp"
37 #include "os_share_bsd.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/safepointMechanism.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 // put OS-includes here
58 # include <sys/types.h>
59 # include <sys/mman.h>
60 # include <pthread.h>
61 # include <signal.h>
62 # include <errno.h>
63 # include <dlfcn.h>
64 # include <stdlib.h>
65 # include <stdio.h>
66 # include <unistd.h>
67 # include <sys/resource.h>
68 # include <pthread.h>
69 # include <sys/stat.h>
70 # include <sys/time.h>
71 # include <sys/utsname.h>
72 # include <sys/socket.h>
73 # include <sys/wait.h>
74 # include <pwd.h>
75 # include <poll.h>
76 #ifndef __OpenBSD__
77 # include <ucontext.h>
78 #endif
79
80 #if !defined(__APPLE__) && !defined(__NetBSD__)
81 # include <pthread_np.h>
82 #endif
83
84 // needed by current_stack_region() workaround for Mavericks
85 #if defined(__APPLE__)
86 # include <errno.h>
87 # include <sys/types.h>
88 # include <sys/sysctl.h>
89 # define DEFAULT_MAIN_THREAD_STACK_PAGES 2048
90 # define OS_X_10_9_0_KERNEL_MAJOR_VERSION 13
91 #endif
92
93 #ifdef AMD64
94 #define SPELL_REG_SP "rsp"
95 #define SPELL_REG_FP "rbp"
96 #else
97 #define SPELL_REG_SP "esp"
98 #define SPELL_REG_FP "ebp"
99 #endif // AMD64
100
101 #ifdef __FreeBSD__
102 # define context_trapno uc_mcontext.mc_trapno
103 # ifdef AMD64
104 # define context_pc uc_mcontext.mc_rip
105 # define context_sp uc_mcontext.mc_rsp
106 # define context_fp uc_mcontext.mc_rbp
107 # define context_rip uc_mcontext.mc_rip
108 # define context_rsp uc_mcontext.mc_rsp
109 # define context_rbp uc_mcontext.mc_rbp
110 # define context_rax uc_mcontext.mc_rax
111 # define context_rbx uc_mcontext.mc_rbx
112 # define context_rcx uc_mcontext.mc_rcx
113 # define context_rdx uc_mcontext.mc_rdx
114 # define context_rsi uc_mcontext.mc_rsi
115 # define context_rdi uc_mcontext.mc_rdi
116 # define context_r8 uc_mcontext.mc_r8
117 # define context_r9 uc_mcontext.mc_r9
118 # define context_r10 uc_mcontext.mc_r10
119 # define context_r11 uc_mcontext.mc_r11
120 # define context_r12 uc_mcontext.mc_r12
121 # define context_r13 uc_mcontext.mc_r13
122 # define context_r14 uc_mcontext.mc_r14
123 # define context_r15 uc_mcontext.mc_r15
124 # define context_flags uc_mcontext.mc_flags
125 # define context_err uc_mcontext.mc_err
126 # else
127 # define context_pc uc_mcontext.mc_eip
128 # define context_sp uc_mcontext.mc_esp
129 # define context_fp uc_mcontext.mc_ebp
130 # define context_eip uc_mcontext.mc_eip
131 # define context_esp uc_mcontext.mc_esp
132 # define context_eax uc_mcontext.mc_eax
133 # define context_ebx uc_mcontext.mc_ebx
134 # define context_ecx uc_mcontext.mc_ecx
135 # define context_edx uc_mcontext.mc_edx
136 # define context_ebp uc_mcontext.mc_ebp
137 # define context_esi uc_mcontext.mc_esi
138 # define context_edi uc_mcontext.mc_edi
139 # define context_eflags uc_mcontext.mc_eflags
140 # define context_trapno uc_mcontext.mc_trapno
141 # endif
142 #endif
143
144 #ifdef __APPLE__
145 # if __DARWIN_UNIX03 && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5)
146 // 10.5 UNIX03 member name prefixes
147 #define DU3_PREFIX(s, m) __ ## s.__ ## m
148 # else
149 #define DU3_PREFIX(s, m) s ## . ## m
150 # endif
151
152 # ifdef AMD64
153 # define context_pc context_rip
154 # define context_sp context_rsp
155 # define context_fp context_rbp
156 # define context_rip uc_mcontext->DU3_PREFIX(ss,rip)
157 # define context_rsp uc_mcontext->DU3_PREFIX(ss,rsp)
158 # define context_rax uc_mcontext->DU3_PREFIX(ss,rax)
159 # define context_rbx uc_mcontext->DU3_PREFIX(ss,rbx)
160 # define context_rcx uc_mcontext->DU3_PREFIX(ss,rcx)
161 # define context_rdx uc_mcontext->DU3_PREFIX(ss,rdx)
162 # define context_rbp uc_mcontext->DU3_PREFIX(ss,rbp)
163 # define context_rsi uc_mcontext->DU3_PREFIX(ss,rsi)
164 # define context_rdi uc_mcontext->DU3_PREFIX(ss,rdi)
165 # define context_r8 uc_mcontext->DU3_PREFIX(ss,r8)
166 # define context_r9 uc_mcontext->DU3_PREFIX(ss,r9)
167 # define context_r10 uc_mcontext->DU3_PREFIX(ss,r10)
168 # define context_r11 uc_mcontext->DU3_PREFIX(ss,r11)
169 # define context_r12 uc_mcontext->DU3_PREFIX(ss,r12)
170 # define context_r13 uc_mcontext->DU3_PREFIX(ss,r13)
171 # define context_r14 uc_mcontext->DU3_PREFIX(ss,r14)
172 # define context_r15 uc_mcontext->DU3_PREFIX(ss,r15)
173 # define context_flags uc_mcontext->DU3_PREFIX(ss,rflags)
174 # define context_trapno uc_mcontext->DU3_PREFIX(es,trapno)
175 # define context_err uc_mcontext->DU3_PREFIX(es,err)
176 # else
177 # define context_pc context_eip
178 # define context_sp context_esp
179 # define context_fp context_ebp
180 # define context_eip uc_mcontext->DU3_PREFIX(ss,eip)
181 # define context_esp uc_mcontext->DU3_PREFIX(ss,esp)
182 # define context_eax uc_mcontext->DU3_PREFIX(ss,eax)
183 # define context_ebx uc_mcontext->DU3_PREFIX(ss,ebx)
184 # define context_ecx uc_mcontext->DU3_PREFIX(ss,ecx)
185 # define context_edx uc_mcontext->DU3_PREFIX(ss,edx)
186 # define context_ebp uc_mcontext->DU3_PREFIX(ss,ebp)
187 # define context_esi uc_mcontext->DU3_PREFIX(ss,esi)
188 # define context_edi uc_mcontext->DU3_PREFIX(ss,edi)
189 # define context_eflags uc_mcontext->DU3_PREFIX(ss,eflags)
190 # define context_trapno uc_mcontext->DU3_PREFIX(es,trapno)
191 # endif
192 #endif
193
194 #ifdef __OpenBSD__
195 # define context_trapno sc_trapno
196 # ifdef AMD64
197 # define context_pc sc_rip
198 # define context_sp sc_rsp
199 # define context_fp sc_rbp
200 # define context_rip sc_rip
201 # define context_rsp sc_rsp
202 # define context_rbp sc_rbp
203 # define context_rax sc_rax
204 # define context_rbx sc_rbx
205 # define context_rcx sc_rcx
206 # define context_rdx sc_rdx
207 # define context_rsi sc_rsi
208 # define context_rdi sc_rdi
209 # define context_r8 sc_r8
210 # define context_r9 sc_r9
211 # define context_r10 sc_r10
212 # define context_r11 sc_r11
213 # define context_r12 sc_r12
214 # define context_r13 sc_r13
215 # define context_r14 sc_r14
216 # define context_r15 sc_r15
217 # define context_flags sc_rflags
218 # define context_err sc_err
219 # else
220 # define context_pc sc_eip
221 # define context_sp sc_esp
222 # define context_fp sc_ebp
223 # define context_eip sc_eip
224 # define context_esp sc_esp
225 # define context_eax sc_eax
226 # define context_ebx sc_ebx
227 # define context_ecx sc_ecx
228 # define context_edx sc_edx
229 # define context_ebp sc_ebp
230 # define context_esi sc_esi
231 # define context_edi sc_edi
232 # define context_eflags sc_eflags
233 # define context_trapno sc_trapno
234 # endif
235 #endif
236
237 #ifdef __NetBSD__
238 # define context_trapno uc_mcontext.__gregs[_REG_TRAPNO]
239 # ifdef AMD64
240 # define __register_t __greg_t
241 # define context_pc uc_mcontext.__gregs[_REG_RIP]
242 # define context_sp uc_mcontext.__gregs[_REG_URSP]
243 # define context_fp uc_mcontext.__gregs[_REG_RBP]
244 # define context_rip uc_mcontext.__gregs[_REG_RIP]
245 # define context_rsp uc_mcontext.__gregs[_REG_URSP]
246 # define context_rax uc_mcontext.__gregs[_REG_RAX]
247 # define context_rbx uc_mcontext.__gregs[_REG_RBX]
248 # define context_rcx uc_mcontext.__gregs[_REG_RCX]
249 # define context_rdx uc_mcontext.__gregs[_REG_RDX]
250 # define context_rbp uc_mcontext.__gregs[_REG_RBP]
251 # define context_rsi uc_mcontext.__gregs[_REG_RSI]
252 # define context_rdi uc_mcontext.__gregs[_REG_RDI]
253 # define context_r8 uc_mcontext.__gregs[_REG_R8]
254 # define context_r9 uc_mcontext.__gregs[_REG_R9]
255 # define context_r10 uc_mcontext.__gregs[_REG_R10]
256 # define context_r11 uc_mcontext.__gregs[_REG_R11]
257 # define context_r12 uc_mcontext.__gregs[_REG_R12]
258 # define context_r13 uc_mcontext.__gregs[_REG_R13]
259 # define context_r14 uc_mcontext.__gregs[_REG_R14]
260 # define context_r15 uc_mcontext.__gregs[_REG_R15]
261 # define context_flags uc_mcontext.__gregs[_REG_RFL]
262 # define context_err uc_mcontext.__gregs[_REG_ERR]
263 # else
264 # define context_pc uc_mcontext.__gregs[_REG_EIP]
265 # define context_sp uc_mcontext.__gregs[_REG_UESP]
266 # define context_fp uc_mcontext.__gregs[_REG_EBP]
267 # define context_eip uc_mcontext.__gregs[_REG_EIP]
268 # define context_esp uc_mcontext.__gregs[_REG_UESP]
269 # define context_eax uc_mcontext.__gregs[_REG_EAX]
270 # define context_ebx uc_mcontext.__gregs[_REG_EBX]
271 # define context_ecx uc_mcontext.__gregs[_REG_ECX]
272 # define context_edx uc_mcontext.__gregs[_REG_EDX]
273 # define context_ebp uc_mcontext.__gregs[_REG_EBP]
274 # define context_esi uc_mcontext.__gregs[_REG_ESI]
275 # define context_edi uc_mcontext.__gregs[_REG_EDI]
276 # define context_eflags uc_mcontext.__gregs[_REG_EFL]
277 # define context_trapno uc_mcontext.__gregs[_REG_TRAPNO]
278 # endif
279 #endif
280
281 address os::current_stack_pointer() {
282 #if defined(__clang__) || defined(__llvm__)
283 void *esp;
284 __asm__("mov %%" SPELL_REG_SP ", %0":"=r"(esp));
285 return (address) esp;
286 #elif defined(SPARC_WORKS)
287 void *esp;
288 __asm__("mov %%" SPELL_REG_SP ", %0":"=r"(esp));
289 return (address) ((char*)esp + sizeof(long)*2);
290 #else
291 register void *esp __asm__ (SPELL_REG_SP);
292 return (address) esp;
293 #endif
294 }
295
296 char* os::non_memory_address_word() {
297 // Must never look like an address returned by reserve_memory,
298 // even in its subfields (as defined by the CPU immediate fields,
299 // if the CPU splits constants across multiple instructions).
300
301 return (char*) -1;
302 }
303
304 address os::Bsd::ucontext_get_pc(const ucontext_t * uc) {
305 return (address)uc->context_pc;
306 }
307
308 void os::Bsd::ucontext_set_pc(ucontext_t * uc, address pc) {
309 uc->context_pc = (intptr_t)pc ;
310 }
311
312 intptr_t* os::Bsd::ucontext_get_sp(const ucontext_t * uc) {
313 return (intptr_t*)uc->context_sp;
314 }
315
316 intptr_t* os::Bsd::ucontext_get_fp(const ucontext_t * uc) {
317 return (intptr_t*)uc->context_fp;
318 }
319
320 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
321 // is currently interrupted by SIGPROF.
322 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
323 // frames. Currently we don't do that on Bsd, so it's the same as
324 // os::fetch_frame_from_context().
325 // This method is also used for stack overflow signal handling.
326 ExtendedPC os::Bsd::fetch_frame_from_ucontext(Thread* thread,
327 const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
328
329 assert(thread != NULL, "just checking");
330 assert(ret_sp != NULL, "just checking");
331 assert(ret_fp != NULL, "just checking");
332
333 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
334 }
335
336 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
337 intptr_t** ret_sp, intptr_t** ret_fp) {
338
339 ExtendedPC epc;
340 const ucontext_t* uc = (const ucontext_t*)ucVoid;
341
342 if (uc != NULL) {
343 epc = ExtendedPC(os::Bsd::ucontext_get_pc(uc));
344 if (ret_sp) *ret_sp = os::Bsd::ucontext_get_sp(uc);
345 if (ret_fp) *ret_fp = os::Bsd::ucontext_get_fp(uc);
346 } else {
347 // construct empty ExtendedPC for return value checking
348 epc = ExtendedPC(NULL);
349 if (ret_sp) *ret_sp = (intptr_t *)NULL;
350 if (ret_fp) *ret_fp = (intptr_t *)NULL;
351 }
352
353 return epc;
354 }
355
356 frame os::fetch_frame_from_context(const void* ucVoid) {
357 intptr_t* sp;
358 intptr_t* fp;
359 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
360 return frame(sp, fp, epc.pc());
361 }
362
363 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
364 intptr_t* sp;
365 intptr_t* fp;
366 ExtendedPC epc = os::Bsd::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp);
367 return frame(sp, fp, epc.pc());
368 }
369
370 bool os::Bsd::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
371 address pc = (address) os::Bsd::ucontext_get_pc(uc);
372 if (Interpreter::contains(pc)) {
373 // interpreter performs stack banging after the fixed frame header has
374 // been generated while the compilers perform it before. To maintain
375 // semantic consistency between interpreted and compiled frames, the
376 // method returns the Java sender of the current frame.
377 *fr = os::fetch_frame_from_ucontext(thread, uc);
378 if (!fr->is_first_java_frame()) {
379 // get_frame_at_stack_banging_point() is only called when we
380 // have well defined stacks so java_sender() calls do not need
381 // to assert safe_for_sender() first.
382 *fr = fr->java_sender();
383 }
384 } else {
385 // more complex code with compiled code
386 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
387 CodeBlob* cb = CodeCache::find_blob(pc);
388 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
389 // Not sure where the pc points to, fallback to default
390 // stack overflow handling
391 return false;
392 } else {
393 *fr = os::fetch_frame_from_ucontext(thread, uc);
394 // in compiled code, the stack banging is performed just after the return pc
395 // has been pushed on the stack
396 *fr = frame(fr->sp() + 1, fr->fp(), (address)*(fr->sp()));
397 if (!fr->is_java_frame()) {
398 // See java_sender() comment above.
399 *fr = fr->java_sender();
400 }
401 }
402 }
403 assert(fr->is_java_frame(), "Safety check");
404 return true;
405 }
406
407 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
408 // turned off by -fomit-frame-pointer,
409 frame os::get_sender_for_C_frame(frame* fr) {
410 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
411 }
412
413 intptr_t* _get_previous_fp() {
414 #if defined(SPARC_WORKS) || defined(__clang__) || defined(__llvm__)
415 intptr_t **ebp;
416 __asm__("mov %%" SPELL_REG_FP ", %0":"=r"(ebp));
417 #else
418 register intptr_t **ebp __asm__ (SPELL_REG_FP);
419 #endif
420 // ebp is for this frame (_get_previous_fp). We want the ebp for the
421 // caller of os::current_frame*(), so go up two frames. However, for
422 // optimized builds, _get_previous_fp() will be inlined, so only go
423 // up 1 frame in that case.
424 #ifdef _NMT_NOINLINE_
425 return **(intptr_t***)ebp;
426 #else
427 return *ebp;
428 #endif
429 }
430
431
432 frame os::current_frame() {
433 intptr_t* fp = _get_previous_fp();
434 frame myframe((intptr_t*)os::current_stack_pointer(),
435 (intptr_t*)fp,
436 CAST_FROM_FN_PTR(address, os::current_frame));
437 if (os::is_first_C_frame(&myframe)) {
438 // stack is not walkable
439 return frame();
440 } else {
441 return os::get_sender_for_C_frame(&myframe);
442 }
443 }
444
445 // Utility functions
446
447 // From IA32 System Programming Guide
448 enum {
449 trap_page_fault = 0xE
450 };
451
452 extern "C" JNIEXPORT int
453 JVM_handle_bsd_signal(int sig,
454 siginfo_t* info,
455 void* ucVoid,
456 int abort_if_unrecognized) {
457 ucontext_t* uc = (ucontext_t*) ucVoid;
458
459 Thread* t = Thread::current_or_null_safe();
460
461 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
462 // (no destructors can be run)
463 os::ThreadCrashProtection::check_crash_protection(sig, t);
464
465 SignalHandlerMark shm(t);
466
467 // Note: it's not uncommon that JNI code uses signal/sigset to install
468 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
469 // or have a SIGILL handler when detecting CPU type). When that happens,
470 // JVM_handle_bsd_signal() might be invoked with junk info/ucVoid. To
471 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
472 // that do not require siginfo/ucontext first.
473
474 if (sig == SIGPIPE || sig == SIGXFSZ) {
475 // allow chained handler to go first
476 if (os::Bsd::chained_handler(sig, info, ucVoid)) {
477 return true;
478 } else {
479 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
480 return true;
481 }
482 }
483
484 JavaThread* thread = NULL;
485 VMThread* vmthread = NULL;
486 if (os::Bsd::signal_handlers_are_installed) {
487 if (t != NULL ){
488 if(t->is_Java_thread()) {
489 thread = (JavaThread*)t;
490 }
491 else if(t->is_VM_thread()){
492 vmthread = (VMThread *)t;
493 }
494 }
495 }
496 /*
497 NOTE: does not seem to work on bsd.
498 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
499 // can't decode this kind of signal
500 info = NULL;
501 } else {
502 assert(sig == info->si_signo, "bad siginfo");
503 }
504 */
505 // decide if this trap can be handled by a stub
506 address stub = NULL;
507
508 address pc = NULL;
509
510 //%note os_trap_1
511 if (info != NULL && uc != NULL && thread != NULL) {
512 pc = (address) os::Bsd::ucontext_get_pc(uc);
513
514 if (StubRoutines::is_safefetch_fault(pc)) {
515 os::Bsd::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
516 return 1;
517 }
518
519 // Handle ALL stack overflow variations here
520 if (sig == SIGSEGV || sig == SIGBUS) {
521 address addr = (address) info->si_addr;
522
523 // check if fault address is within thread stack
524 if (thread->is_in_full_stack(addr)) {
525 // stack overflow
526 if (thread->in_stack_yellow_reserved_zone(addr)) {
527 if (thread->thread_state() == _thread_in_Java) {
528 if (thread->in_stack_reserved_zone(addr)) {
529 frame fr;
530 if (os::Bsd::get_frame_at_stack_banging_point(thread, uc, &fr)) {
531 assert(fr.is_java_frame(), "Must be a Java frame");
532 frame activation = SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
533 if (activation.sp() != NULL) {
534 thread->disable_stack_reserved_zone();
535 if (activation.is_interpreted_frame()) {
536 thread->set_reserved_stack_activation((address)(
537 activation.fp() + frame::interpreter_frame_initial_sp_offset));
538 } else {
539 thread->set_reserved_stack_activation((address)activation.unextended_sp());
540 }
541 return 1;
542 }
543 }
544 }
545 // Throw a stack overflow exception. Guard pages will be reenabled
546 // while unwinding the stack.
547 thread->disable_stack_yellow_reserved_zone();
548 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
549 } else {
550 // Thread was in the vm or native code. Return and try to finish.
551 thread->disable_stack_yellow_reserved_zone();
552 return 1;
553 }
554 } else if (thread->in_stack_red_zone(addr)) {
555 // Fatal red zone violation. Disable the guard pages and fall through
556 // to handle_unexpected_exception way down below.
557 thread->disable_stack_red_zone();
558 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
559 }
560 }
561 }
562
563 if ((sig == SIGSEGV || sig == SIGBUS) && VM_Version::is_cpuinfo_segv_addr(pc)) {
564 // Verify that OS save/restore AVX registers.
565 stub = VM_Version::cpuinfo_cont_addr();
566 }
567
568 // We test if stub is already set (by the stack overflow code
569 // above) so it is not overwritten by the code that follows. This
570 // check is not required on other platforms, because on other
571 // platforms we check for SIGSEGV only or SIGBUS only, where here
572 // we have to check for both SIGSEGV and SIGBUS.
573 if (thread->thread_state() == _thread_in_Java && stub == NULL) {
574 // Java thread running in Java code => find exception handler if any
575 // a fault inside compiled code, the interpreter, or a stub
576
577 if ((sig == SIGSEGV || sig == SIGBUS) && SafepointMechanism::is_poll_address((address)info->si_addr)) {
578 stub = SharedRuntime::get_poll_stub(pc);
579 #if defined(__APPLE__)
580 // 32-bit Darwin reports a SIGBUS for nearly all memory access exceptions.
581 // 64-bit Darwin may also use a SIGBUS (seen with compressed oops).
582 // Catching SIGBUS here prevents the implicit SIGBUS NULL check below from
583 // being called, so only do so if the implicit NULL check is not necessary.
584 } else if (sig == SIGBUS && !MacroAssembler::uses_implicit_null_check(info->si_addr)) {
585 #else
586 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
587 #endif
588 // BugId 4454115: A read from a MappedByteBuffer can fault
589 // here if the underlying file has been truncated.
590 // Do not crash the VM in such a case.
591 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
592 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
593 bool is_unsafe_arraycopy = thread->doing_unsafe_access() && UnsafeCopyMemory::contains_pc(pc);
594 if ((nm != NULL && nm->has_unsafe_access()) || is_unsafe_arraycopy) {
595 address next_pc = Assembler::locate_next_instruction(pc);
596 if (is_unsafe_arraycopy) {
597 next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
598 }
599 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
600 }
601 }
602 else
603
604 #ifdef AMD64
605 if (sig == SIGFPE &&
606 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
607 stub =
608 SharedRuntime::
609 continuation_for_implicit_exception(thread,
610 pc,
611 SharedRuntime::
612 IMPLICIT_DIVIDE_BY_ZERO);
613 #ifdef __APPLE__
614 } else if (sig == SIGFPE && info->si_code == FPE_NOOP) {
615 int op = pc[0];
616
617 // Skip REX
618 if ((pc[0] & 0xf0) == 0x40) {
619 op = pc[1];
620 } else {
621 op = pc[0];
622 }
623
624 // Check for IDIV
625 if (op == 0xF7) {
626 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime:: IMPLICIT_DIVIDE_BY_ZERO);
627 } else {
628 // TODO: handle more cases if we are using other x86 instructions
629 // that can generate SIGFPE signal.
630 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
631 fatal("please update this code.");
632 }
633 #endif /* __APPLE__ */
634
635 #else
636 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
637 // HACK: si_code does not work on bsd 2.2.12-20!!!
638 int op = pc[0];
639 if (op == 0xDB) {
640 // FIST
641 // TODO: The encoding of D2I in i486.ad can cause an exception
642 // prior to the fist instruction if there was an invalid operation
643 // pending. We want to dismiss that exception. From the win_32
644 // side it also seems that if it really was the fist causing
645 // the exception that we do the d2i by hand with different
646 // rounding. Seems kind of weird.
647 // NOTE: that we take the exception at the NEXT floating point instruction.
648 assert(pc[0] == 0xDB, "not a FIST opcode");
649 assert(pc[1] == 0x14, "not a FIST opcode");
650 assert(pc[2] == 0x24, "not a FIST opcode");
651 return true;
652 } else if (op == 0xF7) {
653 // IDIV
654 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
655 } else {
656 // TODO: handle more cases if we are using other x86 instructions
657 // that can generate SIGFPE signal on bsd.
658 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
659 fatal("please update this code.");
660 }
661 #endif // AMD64
662 } else if ((sig == SIGSEGV || sig == SIGBUS) &&
663 MacroAssembler::uses_implicit_null_check(info->si_addr)) {
664 // Determination of interpreter/vtable stub/compiled code null exception
665 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
666 }
667 } else if ((thread->thread_state() == _thread_in_vm ||
668 thread->thread_state() == _thread_in_native) &&
669 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
670 thread->doing_unsafe_access()) {
671 address next_pc = Assembler::locate_next_instruction(pc);
672 if (UnsafeCopyMemory::contains_pc(pc)) {
673 next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
674 }
675 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
676 }
677
678 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
679 // and the heap gets shrunk before the field access.
680 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
681 address addr = JNI_FastGetField::find_slowcase_pc(pc);
682 if (addr != (address)-1) {
683 stub = addr;
684 }
685 }
686 }
687
688 #ifndef AMD64
689 // Execution protection violation
690 //
691 // This should be kept as the last step in the triage. We don't
692 // have a dedicated trap number for a no-execute fault, so be
693 // conservative and allow other handlers the first shot.
694 //
695 // Note: We don't test that info->si_code == SEGV_ACCERR here.
696 // this si_code is so generic that it is almost meaningless; and
697 // the si_code for this condition may change in the future.
698 // Furthermore, a false-positive should be harmless.
699 if (UnguardOnExecutionViolation > 0 &&
700 (sig == SIGSEGV || sig == SIGBUS) &&
701 uc->context_trapno == trap_page_fault) {
702 int page_size = os::vm_page_size();
703 address addr = (address) info->si_addr;
704 address pc = os::Bsd::ucontext_get_pc(uc);
705 // Make sure the pc and the faulting address are sane.
706 //
707 // If an instruction spans a page boundary, and the page containing
708 // the beginning of the instruction is executable but the following
709 // page is not, the pc and the faulting address might be slightly
710 // different - we still want to unguard the 2nd page in this case.
711 //
712 // 15 bytes seems to be a (very) safe value for max instruction size.
713 bool pc_is_near_addr =
714 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
715 bool instr_spans_page_boundary =
716 (align_down((intptr_t) pc ^ (intptr_t) addr,
717 (intptr_t) page_size) > 0);
718
719 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
720 static volatile address last_addr =
721 (address) os::non_memory_address_word();
722
723 // In conservative mode, don't unguard unless the address is in the VM
724 if (addr != last_addr &&
725 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
726
727 // Set memory to RWX and retry
728 address page_start = align_down(addr, page_size);
729 bool res = os::protect_memory((char*) page_start, page_size,
730 os::MEM_PROT_RWX);
731
732 log_debug(os)("Execution protection violation "
733 "at " INTPTR_FORMAT
734 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
735 p2i(page_start), (res ? "success" : "failed"), errno);
736 stub = pc;
737
738 // Set last_addr so if we fault again at the same address, we don't end
739 // up in an endless loop.
740 //
741 // There are two potential complications here. Two threads trapping at
742 // the same address at the same time could cause one of the threads to
743 // think it already unguarded, and abort the VM. Likely very rare.
744 //
745 // The other race involves two threads alternately trapping at
746 // different addresses and failing to unguard the page, resulting in
747 // an endless loop. This condition is probably even more unlikely than
748 // the first.
749 //
750 // Although both cases could be avoided by using locks or thread local
751 // last_addr, these solutions are unnecessary complication: this
752 // handler is a best-effort safety net, not a complete solution. It is
753 // disabled by default and should only be used as a workaround in case
754 // we missed any no-execute-unsafe VM code.
755
756 last_addr = addr;
757 }
758 }
759 }
760 #endif // !AMD64
761
762 if (stub != NULL) {
763 // save all thread context in case we need to restore it
764 if (thread != NULL) thread->set_saved_exception_pc(pc);
765
766 os::Bsd::ucontext_set_pc(uc, stub);
767 return true;
768 }
769
770 // signal-chaining
771 if (os::Bsd::chained_handler(sig, info, ucVoid)) {
772 return true;
773 }
774
775 if (!abort_if_unrecognized) {
776 // caller wants another chance, so give it to him
777 return false;
778 }
779
780 if (pc == NULL && uc != NULL) {
781 pc = os::Bsd::ucontext_get_pc(uc);
782 }
783
784 // unmask current signal
785 sigset_t newset;
786 sigemptyset(&newset);
787 sigaddset(&newset, sig);
788 sigprocmask(SIG_UNBLOCK, &newset, NULL);
789
790 VMError::report_and_die(t, sig, pc, info, ucVoid);
791
792 ShouldNotReachHere();
793 return false;
794 }
795
796 // From solaris_i486.s ported to bsd_i486.s
797 extern "C" void fixcw();
798
799 void os::Bsd::init_thread_fpu_state(void) {
800 #ifndef AMD64
801 // Set fpu to 53 bit precision. This happens too early to use a stub.
802 fixcw();
803 #endif // !AMD64
804 }
805
806
807 // Check that the bsd kernel version is 2.4 or higher since earlier
808 // versions do not support SSE without patches.
809 bool os::supports_sse() {
810 return true;
811 }
812
813 bool os::is_allocatable(size_t bytes) {
814 #ifdef AMD64
815 // unused on amd64?
816 return true;
817 #else
818
819 if (bytes < 2 * G) {
820 return true;
821 }
822
823 char* addr = reserve_memory(bytes, NULL);
824
825 if (addr != NULL) {
826 release_memory(addr, bytes);
827 }
828
829 return addr != NULL;
830 #endif // AMD64
831 }
832
833 ////////////////////////////////////////////////////////////////////////////////
834 // thread stack
835
836 // Minimum usable stack sizes required to get to user code. Space for
837 // HotSpot guard pages is added later.
838 size_t os::Posix::_compiler_thread_min_stack_allowed = 48 * K;
839 size_t os::Posix::_java_thread_min_stack_allowed = 48 * K;
840 #ifdef _LP64
841 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
842 #else
843 size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
844 #endif // _LP64
845
846 #ifndef AMD64
847 #ifdef __GNUC__
848 #define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})
849 #endif
850 #endif // AMD64
851
852 // return default stack size for thr_type
853 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
854 // default stack size (compiler thread needs larger stack)
855 #ifdef AMD64
856 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
857 #else
858 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
859 #endif // AMD64
860 return s;
861 }
862
863
864 // Java thread:
865 //
866 // Low memory addresses
867 // +------------------------+
868 // | |\ Java thread created by VM does not have glibc
869 // | glibc guard page | - guard, attached Java thread usually has
870 // | |/ 1 glibc guard page.
871 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
872 // | |\
873 // | HotSpot Guard Pages | - red, yellow and reserved pages
874 // | |/
875 // +------------------------+ JavaThread::stack_reserved_zone_base()
876 // | |\
877 // | Normal Stack | -
878 // | |/
879 // P2 +------------------------+ Thread::stack_base()
880 //
881 // Non-Java thread:
882 //
883 // Low memory addresses
884 // +------------------------+
885 // | |\
886 // | glibc guard page | - usually 1 page
887 // | |/
888 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
889 // | |\
890 // | Normal Stack | -
891 // | |/
892 // P2 +------------------------+ Thread::stack_base()
893 //
894 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
895 // pthread_attr_getstack()
896
897 static void current_stack_region(address * bottom, size_t * size) {
898 #ifdef __APPLE__
899 pthread_t self = pthread_self();
900 void *stacktop = pthread_get_stackaddr_np(self);
901 *size = pthread_get_stacksize_np(self);
902 // workaround for OS X 10.9.0 (Mavericks)
903 // pthread_get_stacksize_np returns 128 pages even though the actual size is 2048 pages
904 if (pthread_main_np() == 1) {
905 // At least on Mac OS 10.12 we have observed stack sizes not aligned
906 // to pages boundaries. This can be provoked by e.g. setrlimit() (ulimit -s xxxx in the
907 // shell). Apparently Mac OS actually rounds upwards to next multiple of page size,
908 // however, we round downwards here to be on the safe side.
909 *size = align_down(*size, getpagesize());
910
911 if ((*size) < (DEFAULT_MAIN_THREAD_STACK_PAGES * (size_t)getpagesize())) {
912 char kern_osrelease[256];
913 size_t kern_osrelease_size = sizeof(kern_osrelease);
914 int ret = sysctlbyname("kern.osrelease", kern_osrelease, &kern_osrelease_size, NULL, 0);
915 if (ret == 0) {
916 // get the major number, atoi will ignore the minor amd micro portions of the version string
917 if (atoi(kern_osrelease) >= OS_X_10_9_0_KERNEL_MAJOR_VERSION) {
918 *size = (DEFAULT_MAIN_THREAD_STACK_PAGES*getpagesize());
919 }
920 }
921 }
922 }
923 *bottom = (address) stacktop - *size;
924 #elif defined(__OpenBSD__)
925 stack_t ss;
926 int rslt = pthread_stackseg_np(pthread_self(), &ss);
927
928 if (rslt != 0)
929 fatal("pthread_stackseg_np failed with error = %d", rslt);
930
931 *bottom = (address)((char *)ss.ss_sp - ss.ss_size);
932 *size = ss.ss_size;
933 #else
934 pthread_attr_t attr;
935
936 int rslt = pthread_attr_init(&attr);
937
938 // JVM needs to know exact stack location, abort if it fails
939 if (rslt != 0)
940 fatal("pthread_attr_init failed with error = %d", rslt);
941
942 rslt = pthread_attr_get_np(pthread_self(), &attr);
943
944 if (rslt != 0)
945 fatal("pthread_attr_get_np failed with error = %d", rslt);
946
947 if (pthread_attr_getstackaddr(&attr, (void **)bottom) != 0 ||
948 pthread_attr_getstacksize(&attr, size) != 0) {
949 fatal("Can not locate current stack attributes!");
950 }
951
952 pthread_attr_destroy(&attr);
953 #endif
954 assert(os::current_stack_pointer() >= *bottom &&
955 os::current_stack_pointer() < *bottom + *size, "just checking");
956 }
957
958 address os::current_stack_base() {
959 address bottom;
960 size_t size;
961 current_stack_region(&bottom, &size);
962 return (bottom + size);
963 }
964
965 size_t os::current_stack_size() {
966 // stack size includes normal stack and HotSpot guard pages
967 address bottom;
968 size_t size;
969 current_stack_region(&bottom, &size);
970 return size;
971 }
972
973 /////////////////////////////////////////////////////////////////////////////
974 // helper functions for fatal error handler
975
976 void os::print_context(outputStream *st, const void *context) {
977 if (context == NULL) return;
978
979 const ucontext_t *uc = (const ucontext_t*)context;
980 st->print_cr("Registers:");
981 #ifdef AMD64
982 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->context_rax);
983 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->context_rbx);
984 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->context_rcx);
985 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->context_rdx);
986 st->cr();
987 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->context_rsp);
988 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->context_rbp);
989 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->context_rsi);
990 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->context_rdi);
991 st->cr();
992 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->context_r8);
993 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->context_r9);
994 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->context_r10);
995 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->context_r11);
996 st->cr();
997 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->context_r12);
998 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->context_r13);
999 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->context_r14);
1000 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->context_r15);
1001 st->cr();
1002 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->context_rip);
1003 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->context_flags);
1004 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->context_err);
1005 st->cr();
1006 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->context_trapno);
1007 #else
1008 st->print( "EAX=" INTPTR_FORMAT, (intptr_t)uc->context_eax);
1009 st->print(", EBX=" INTPTR_FORMAT, (intptr_t)uc->context_ebx);
1010 st->print(", ECX=" INTPTR_FORMAT, (intptr_t)uc->context_ecx);
1011 st->print(", EDX=" INTPTR_FORMAT, (intptr_t)uc->context_edx);
1012 st->cr();
1013 st->print( "ESP=" INTPTR_FORMAT, (intptr_t)uc->context_esp);
1014 st->print(", EBP=" INTPTR_FORMAT, (intptr_t)uc->context_ebp);
1015 st->print(", ESI=" INTPTR_FORMAT, (intptr_t)uc->context_esi);
1016 st->print(", EDI=" INTPTR_FORMAT, (intptr_t)uc->context_edi);
1017 st->cr();
1018 st->print( "EIP=" INTPTR_FORMAT, (intptr_t)uc->context_eip);
1019 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->context_eflags);
1020 #endif // AMD64
1021 st->cr();
1022 st->cr();
1023
1024 intptr_t *sp = (intptr_t *)os::Bsd::ucontext_get_sp(uc);
1025 st->print_cr("Top of Stack: (sp=" INTPTR_FORMAT ")", (intptr_t)sp);
1026 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
1027 st->cr();
1028
1029 // Note: it may be unsafe to inspect memory near pc. For example, pc may
1030 // point to garbage if entry point in an nmethod is corrupted. Leave
1031 // this at the end, and hope for the best.
1032 address pc = os::Bsd::ucontext_get_pc(uc);
1033 print_instructions(st, pc, sizeof(char));
1034 st->cr();
1035 }
1036
1037 void os::print_register_info(outputStream *st, const void *context) {
1038 if (context == NULL) return;
1039
1040 const ucontext_t *uc = (const ucontext_t*)context;
1041
1042 st->print_cr("Register to memory mapping:");
1043 st->cr();
1044
1045 // this is horrendously verbose but the layout of the registers in the
1046 // context does not match how we defined our abstract Register set, so
1047 // we can't just iterate through the gregs area
1048
1049 // this is only for the "general purpose" registers
1050
1051 #ifdef AMD64
1052 st->print("RAX="); print_location(st, uc->context_rax);
1053 st->print("RBX="); print_location(st, uc->context_rbx);
1054 st->print("RCX="); print_location(st, uc->context_rcx);
1055 st->print("RDX="); print_location(st, uc->context_rdx);
1056 st->print("RSP="); print_location(st, uc->context_rsp);
1057 st->print("RBP="); print_location(st, uc->context_rbp);
1058 st->print("RSI="); print_location(st, uc->context_rsi);
1059 st->print("RDI="); print_location(st, uc->context_rdi);
1060 st->print("R8 ="); print_location(st, uc->context_r8);
1061 st->print("R9 ="); print_location(st, uc->context_r9);
1062 st->print("R10="); print_location(st, uc->context_r10);
1063 st->print("R11="); print_location(st, uc->context_r11);
1064 st->print("R12="); print_location(st, uc->context_r12);
1065 st->print("R13="); print_location(st, uc->context_r13);
1066 st->print("R14="); print_location(st, uc->context_r14);
1067 st->print("R15="); print_location(st, uc->context_r15);
1068 #else
1069 st->print("EAX="); print_location(st, uc->context_eax);
1070 st->print("EBX="); print_location(st, uc->context_ebx);
1071 st->print("ECX="); print_location(st, uc->context_ecx);
1072 st->print("EDX="); print_location(st, uc->context_edx);
1073 st->print("ESP="); print_location(st, uc->context_esp);
1074 st->print("EBP="); print_location(st, uc->context_ebp);
1075 st->print("ESI="); print_location(st, uc->context_esi);
1076 st->print("EDI="); print_location(st, uc->context_edi);
1077 #endif // AMD64
1078
1079 st->cr();
1080 }
1081
1082 void os::setup_fpu() {
1083 #ifndef AMD64
1084 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
1085 __asm__ volatile ( "fldcw (%0)" :
1086 : "r" (fpu_cntrl) : "memory");
1087 #endif // !AMD64
1088 }
1089
1090 #ifndef PRODUCT
1091 void os::verify_stack_alignment() {
1092 }
1093 #endif
1094
1095 int os::extra_bang_size_in_bytes() {
1096 // JDK-8050147 requires the full cache line bang for x86.
1097 return VM_Version::L1_line_size();
1098 }