1 /*
2 * Copyright (c) 1999, 2017, 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 "memory/allocation.inline.hpp"
36 #include "os_share_linux.hpp"
37 #include "prims/jniFastGetField.hpp"
38 #include "prims/jvm_misc.hpp"
39 #include "runtime/arguments.hpp"
40 #include "runtime/extendedPC.hpp"
41 #include "runtime/frame.inline.hpp"
42 #include "runtime/interfaceSupport.hpp"
43 #include "runtime/java.hpp"
44 #include "runtime/javaCalls.hpp"
45 #include "runtime/mutexLocker.hpp"
46 #include "runtime/osThread.hpp"
47 #include "runtime/sharedRuntime.hpp"
48 #include "runtime/stubRoutines.hpp"
49 #include "runtime/thread.inline.hpp"
50 #include "runtime/timer.hpp"
51 #include "services/memTracker.hpp"
52 #include "utilities/align.hpp"
53 #include "utilities/events.hpp"
54 #include "utilities/vmError.hpp"
55
56 // put OS-includes here
57 # include <sys/types.h>
58 # include <sys/mman.h>
59 # include <pthread.h>
60 # include <signal.h>
61 # include <errno.h>
62 # include <dlfcn.h>
63 # include <stdlib.h>
64 # include <stdio.h>
65 # include <unistd.h>
66 # include <sys/resource.h>
67 # include <pthread.h>
68 # include <sys/stat.h>
69 # include <sys/time.h>
70 # include <sys/utsname.h>
71 # include <sys/socket.h>
72 # include <sys/wait.h>
73 # include <pwd.h>
74 # include <poll.h>
75 # include <ucontext.h>
76 #ifndef AMD64
77 # include <fpu_control.h>
78 #endif
79
80 #ifdef AMD64
81 #define REG_SP REG_RSP
82 #define REG_PC REG_RIP
83 #define REG_FP REG_RBP
84 #define SPELL_REG_SP "rsp"
85 #define SPELL_REG_FP "rbp"
86 #else
87 #define REG_SP REG_UESP
88 #define REG_PC REG_EIP
89 #define REG_FP REG_EBP
90 #define SPELL_REG_SP "esp"
91 #define SPELL_REG_FP "ebp"
92 #endif // AMD64
93
94 address os::current_stack_pointer() {
95 #ifdef SPARC_WORKS
96 register void *esp;
97 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
98 return (address) ((char*)esp + sizeof(long)*2);
99 #elif defined(__clang__)
100 intptr_t* esp;
101 __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):);
102 return (address) esp;
103 #else
104 register void *esp __asm__ (SPELL_REG_SP);
105 return (address) esp;
106 #endif
107 }
108
109 char* os::non_memory_address_word() {
110 // Must never look like an address returned by reserve_memory,
111 // even in its subfields (as defined by the CPU immediate fields,
112 // if the CPU splits constants across multiple instructions).
113
114 return (char*) -1;
115 }
116
117 void os::initialize_thread(Thread* thr) {
118 // Nothing to do.
119 }
120
121 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
122 return (address)uc->uc_mcontext.gregs[REG_PC];
123 }
124
125 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
126 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc;
127 }
128
129 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
130 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
131 }
132
133 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
134 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
135 }
136
137 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
138 // is currently interrupted by SIGPROF.
139 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
140 // frames. Currently we don't do that on Linux, so it's the same as
141 // os::fetch_frame_from_context().
142 // This method is also used for stack overflow signal handling.
143 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
144 const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
145
146 assert(thread != NULL, "just checking");
147 assert(ret_sp != NULL, "just checking");
148 assert(ret_fp != NULL, "just checking");
149
150 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
151 }
152
153 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
154 intptr_t** ret_sp, intptr_t** ret_fp) {
155
156 ExtendedPC epc;
157 const ucontext_t* uc = (const ucontext_t*)ucVoid;
158
159 if (uc != NULL) {
160 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
161 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
162 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
163 } else {
164 // construct empty ExtendedPC for return value checking
165 epc = ExtendedPC(NULL);
166 if (ret_sp) *ret_sp = (intptr_t *)NULL;
167 if (ret_fp) *ret_fp = (intptr_t *)NULL;
168 }
169
170 return epc;
171 }
172
173 frame os::fetch_frame_from_context(const void* ucVoid) {
174 intptr_t* sp;
175 intptr_t* fp;
176 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
177 return frame(sp, fp, epc.pc());
178 }
179
180 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
181 intptr_t* sp;
182 intptr_t* fp;
183 ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp);
184 return frame(sp, fp, epc.pc());
185 }
186
187 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
188 address pc = (address) os::Linux::ucontext_get_pc(uc);
189 if (Interpreter::contains(pc)) {
190 // interpreter performs stack banging after the fixed frame header has
191 // been generated while the compilers perform it before. To maintain
192 // semantic consistency between interpreted and compiled frames, the
193 // method returns the Java sender of the current frame.
194 *fr = os::fetch_frame_from_ucontext(thread, uc);
195 if (!fr->is_first_java_frame()) {
196 // get_frame_at_stack_banging_point() is only called when we
197 // have well defined stacks so java_sender() calls do not need
198 // to assert safe_for_sender() first.
199 *fr = fr->java_sender();
200 }
201 } else {
202 // more complex code with compiled code
203 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
204 CodeBlob* cb = CodeCache::find_blob(pc);
205 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
206 // Not sure where the pc points to, fallback to default
207 // stack overflow handling
208 return false;
209 } else {
210 // in compiled code, the stack banging is performed just after the return pc
211 // has been pushed on the stack
212 intptr_t* fp = os::Linux::ucontext_get_fp(uc);
213 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
214 *fr = frame(sp + 1, fp, (address)*sp);
215 if (!fr->is_java_frame()) {
216 assert(!fr->is_first_frame(), "Safety check");
217 // See java_sender() comment above.
218 *fr = fr->java_sender();
219 }
220 }
221 }
222 assert(fr->is_java_frame(), "Safety check");
223 return true;
224 }
225
226 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
227 // turned off by -fomit-frame-pointer,
228 frame os::get_sender_for_C_frame(frame* fr) {
229 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
230 }
231
232 intptr_t* _get_previous_fp() {
233 #ifdef SPARC_WORKS
234 register intptr_t **ebp;
235 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
236 #elif defined(__clang__)
237 intptr_t **ebp;
238 __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):);
239 #else
240 register intptr_t **ebp __asm__ (SPELL_REG_FP);
241 #endif
242 // ebp is for this frame (_get_previous_fp). We want the ebp for the
243 // caller of os::current_frame*(), so go up two frames. However, for
244 // optimized builds, _get_previous_fp() will be inlined, so only go
245 // up 1 frame in that case.
246 #ifdef _NMT_NOINLINE_
247 return **(intptr_t***)ebp;
248 #else
249 return *ebp;
250 #endif
251 }
252
253
254 frame os::current_frame() {
255 intptr_t* fp = _get_previous_fp();
256 frame myframe((intptr_t*)os::current_stack_pointer(),
257 (intptr_t*)fp,
258 CAST_FROM_FN_PTR(address, os::current_frame));
259 if (os::is_first_C_frame(&myframe)) {
260 // stack is not walkable
261 return frame();
262 } else {
263 return os::get_sender_for_C_frame(&myframe);
264 }
265 }
266
267 // Utility functions
268
269 // From IA32 System Programming Guide
270 enum {
271 trap_page_fault = 0xE
272 };
273
274 extern "C" JNIEXPORT int
275 JVM_handle_linux_signal(int sig,
276 siginfo_t* info,
277 void* ucVoid,
278 int abort_if_unrecognized) {
279 ucontext_t* uc = (ucontext_t*) ucVoid;
280
281 Thread* t = Thread::current_or_null_safe();
282
283 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
284 // (no destructors can be run)
285 os::ThreadCrashProtection::check_crash_protection(sig, t);
286
287 SignalHandlerMark shm(t);
288
289 // Note: it's not uncommon that JNI code uses signal/sigset to install
290 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
291 // or have a SIGILL handler when detecting CPU type). When that happens,
292 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
293 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
294 // that do not require siginfo/ucontext first.
295
296 if (sig == SIGPIPE || sig == SIGXFSZ) {
297 // allow chained handler to go first
298 if (os::Linux::chained_handler(sig, info, ucVoid)) {
299 return true;
300 } else {
301 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
302 return true;
303 }
304 }
305
306 JavaThread* thread = NULL;
307 VMThread* vmthread = NULL;
308 if (os::Linux::signal_handlers_are_installed) {
309 if (t != NULL ){
310 if(t->is_Java_thread()) {
311 thread = (JavaThread*)t;
312 }
313 else if(t->is_VM_thread()){
314 vmthread = (VMThread *)t;
315 }
316 }
317 }
318 /*
319 NOTE: does not seem to work on linux.
320 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
321 // can't decode this kind of signal
322 info = NULL;
323 } else {
324 assert(sig == info->si_signo, "bad siginfo");
325 }
326 */
327 // decide if this trap can be handled by a stub
328 address stub = NULL;
329
330 address pc = NULL;
331
332 //%note os_trap_1
333 if (info != NULL && uc != NULL && thread != NULL) {
334 pc = (address) os::Linux::ucontext_get_pc(uc);
335
336 if (StubRoutines::is_safefetch_fault(pc)) {
337 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
338 return 1;
339 }
340
341 #ifndef AMD64
342 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs
343 // This can happen in any running code (currently more frequently in
344 // interpreter code but has been seen in compiled code)
345 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) {
346 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due "
347 "to unstable signal handling in this distribution.");
348 }
349 #endif // AMD64
350
351 // Handle ALL stack overflow variations here
352 if (sig == SIGSEGV) {
353 address addr = (address) info->si_addr;
354
355 // check if fault address is within thread stack
356 if (thread->on_local_stack(addr)) {
357 // stack overflow
358 if (thread->in_stack_yellow_reserved_zone(addr)) {
359 if (thread->thread_state() == _thread_in_Java) {
360 if (thread->in_stack_reserved_zone(addr)) {
361 frame fr;
362 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
363 assert(fr.is_java_frame(), "Must be a Java frame");
364 frame activation =
365 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
366 if (activation.sp() != NULL) {
367 thread->disable_stack_reserved_zone();
368 if (activation.is_interpreted_frame()) {
369 thread->set_reserved_stack_activation((address)(
370 activation.fp() + frame::interpreter_frame_initial_sp_offset));
371 } else {
372 thread->set_reserved_stack_activation((address)activation.unextended_sp());
373 }
374 return 1;
375 }
376 }
377 }
378 // Throw a stack overflow exception. Guard pages will be reenabled
379 // while unwinding the stack.
380 thread->disable_stack_yellow_reserved_zone();
381 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
382 } else {
383 // Thread was in the vm or native code. Return and try to finish.
384 thread->disable_stack_yellow_reserved_zone();
385 return 1;
386 }
387 } else if (thread->in_stack_red_zone(addr)) {
388 // Fatal red zone violation. Disable the guard pages and fall through
389 // to handle_unexpected_exception way down below.
390 thread->disable_stack_red_zone();
391 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
392
393 // This is a likely cause, but hard to verify. Let's just print
394 // it as a hint.
395 tty->print_raw_cr("Please check if any of your loaded .so files has "
396 "enabled executable stack (see man page execstack(8))");
397 } else {
398 // Accessing stack address below sp may cause SEGV if current
399 // thread has MAP_GROWSDOWN stack. This should only happen when
400 // current thread was created by user code with MAP_GROWSDOWN flag
401 // and then attached to VM. See notes in os_linux.cpp.
402 if (thread->osthread()->expanding_stack() == 0) {
403 thread->osthread()->set_expanding_stack();
404 if (os::Linux::manually_expand_stack(thread, addr)) {
405 thread->osthread()->clear_expanding_stack();
406 return 1;
407 }
408 thread->osthread()->clear_expanding_stack();
409 } else {
410 fatal("recursive segv. expanding stack.");
411 }
412 }
413 }
414 }
415
416 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) {
417 // Verify that OS save/restore AVX registers.
418 stub = VM_Version::cpuinfo_cont_addr();
419 }
420
421 if (thread->thread_state() == _thread_in_Java) {
422 // Java thread running in Java code => find exception handler if any
423 // a fault inside compiled code, the interpreter, or a stub
424
425 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
426 stub = SharedRuntime::get_poll_stub(pc);
427 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
428 // BugId 4454115: A read from a MappedByteBuffer can fault
429 // here if the underlying file has been truncated.
430 // Do not crash the VM in such a case.
431 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
432 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
433 if (nm != NULL && nm->has_unsafe_access()) {
434 address next_pc = Assembler::locate_next_instruction(pc);
435 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
436 }
437 }
438 else
439
440 #ifdef AMD64
441 if (sig == SIGFPE &&
442 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
443 stub =
444 SharedRuntime::
445 continuation_for_implicit_exception(thread,
446 pc,
447 SharedRuntime::
448 IMPLICIT_DIVIDE_BY_ZERO);
449 #else
450 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
451 // HACK: si_code does not work on linux 2.2.12-20!!!
452 int op = pc[0];
453 if (op == 0xDB) {
454 // FIST
455 // TODO: The encoding of D2I in i486.ad can cause an exception
456 // prior to the fist instruction if there was an invalid operation
457 // pending. We want to dismiss that exception. From the win_32
458 // side it also seems that if it really was the fist causing
459 // the exception that we do the d2i by hand with different
460 // rounding. Seems kind of weird.
461 // NOTE: that we take the exception at the NEXT floating point instruction.
462 assert(pc[0] == 0xDB, "not a FIST opcode");
463 assert(pc[1] == 0x14, "not a FIST opcode");
464 assert(pc[2] == 0x24, "not a FIST opcode");
465 return true;
466 } else if (op == 0xF7) {
467 // IDIV
468 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
469 } else {
470 // TODO: handle more cases if we are using other x86 instructions
471 // that can generate SIGFPE signal on linux.
472 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
473 fatal("please update this code.");
474 }
475 #endif // AMD64
476 } else if (sig == SIGSEGV &&
477 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
478 // Determination of interpreter/vtable stub/compiled code null exception
479 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
480 }
481 } else if (thread->thread_state() == _thread_in_vm &&
482 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
483 thread->doing_unsafe_access()) {
484 address next_pc = Assembler::locate_next_instruction(pc);
485 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
486 }
487
488 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
489 // and the heap gets shrunk before the field access.
490 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
491 address addr = JNI_FastGetField::find_slowcase_pc(pc);
492 if (addr != (address)-1) {
493 stub = addr;
494 }
495 }
496
497 // Check to see if we caught the safepoint code in the
498 // process of write protecting the memory serialization page.
499 // It write enables the page immediately after protecting it
500 // so we can just return to retry the write.
501 if ((sig == SIGSEGV) &&
502 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
503 // Block current thread until the memory serialize page permission restored.
504 os::block_on_serialize_page_trap();
505 return true;
506 }
507 }
508
509 #ifndef AMD64
510 // Execution protection violation
511 //
512 // This should be kept as the last step in the triage. We don't
513 // have a dedicated trap number for a no-execute fault, so be
514 // conservative and allow other handlers the first shot.
515 //
516 // Note: We don't test that info->si_code == SEGV_ACCERR here.
517 // this si_code is so generic that it is almost meaningless; and
518 // the si_code for this condition may change in the future.
519 // Furthermore, a false-positive should be harmless.
520 if (UnguardOnExecutionViolation > 0 &&
521 (sig == SIGSEGV || sig == SIGBUS) &&
522 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
523 int page_size = os::vm_page_size();
524 address addr = (address) info->si_addr;
525 address pc = os::Linux::ucontext_get_pc(uc);
526 // Make sure the pc and the faulting address are sane.
527 //
528 // If an instruction spans a page boundary, and the page containing
529 // the beginning of the instruction is executable but the following
530 // page is not, the pc and the faulting address might be slightly
531 // different - we still want to unguard the 2nd page in this case.
532 //
533 // 15 bytes seems to be a (very) safe value for max instruction size.
534 bool pc_is_near_addr =
535 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
536 bool instr_spans_page_boundary =
537 (align_down((intptr_t) pc ^ (intptr_t) addr,
538 (intptr_t) page_size) > 0);
539
540 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
541 static volatile address last_addr =
542 (address) os::non_memory_address_word();
543
544 // In conservative mode, don't unguard unless the address is in the VM
545 if (addr != last_addr &&
546 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
547
548 // Set memory to RWX and retry
549 address page_start = align_down(addr, page_size);
550 bool res = os::protect_memory((char*) page_start, page_size,
551 os::MEM_PROT_RWX);
552
553 log_debug(os)("Execution protection violation "
554 "at " INTPTR_FORMAT
555 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
556 p2i(page_start), (res ? "success" : "failed"), errno);
557 stub = pc;
558
559 // Set last_addr so if we fault again at the same address, we don't end
560 // up in an endless loop.
561 //
562 // There are two potential complications here. Two threads trapping at
563 // the same address at the same time could cause one of the threads to
564 // think it already unguarded, and abort the VM. Likely very rare.
565 //
566 // The other race involves two threads alternately trapping at
567 // different addresses and failing to unguard the page, resulting in
568 // an endless loop. This condition is probably even more unlikely than
569 // the first.
570 //
571 // Although both cases could be avoided by using locks or thread local
572 // last_addr, these solutions are unnecessary complication: this
573 // handler is a best-effort safety net, not a complete solution. It is
574 // disabled by default and should only be used as a workaround in case
575 // we missed any no-execute-unsafe VM code.
576
577 last_addr = addr;
578 }
579 }
580 }
581 #endif // !AMD64
582
583 if (stub != NULL) {
584 // save all thread context in case we need to restore it
585 if (thread != NULL) thread->set_saved_exception_pc(pc);
586
587 os::Linux::ucontext_set_pc(uc, stub);
588 return true;
589 }
590
591 // signal-chaining
592 if (os::Linux::chained_handler(sig, info, ucVoid)) {
593 return true;
594 }
595
596 if (!abort_if_unrecognized) {
597 // caller wants another chance, so give it to him
598 return false;
599 }
600
601 if (pc == NULL && uc != NULL) {
602 pc = os::Linux::ucontext_get_pc(uc);
603 }
604
605 // unmask current signal
606 sigset_t newset;
607 sigemptyset(&newset);
608 sigaddset(&newset, sig);
609 sigprocmask(SIG_UNBLOCK, &newset, NULL);
610
611 VMError::report_and_die(t, sig, pc, info, ucVoid);
612
613 ShouldNotReachHere();
614 return true; // Mute compiler
615 }
616
617 void os::Linux::init_thread_fpu_state(void) {
618 #ifndef AMD64
619 // set fpu to 53 bit precision
620 set_fpu_control_word(0x27f);
621 #endif // !AMD64
622 }
623
624 int os::Linux::get_fpu_control_word(void) {
625 #ifdef AMD64
626 return 0;
627 #else
628 int fpu_control;
629 _FPU_GETCW(fpu_control);
630 return fpu_control & 0xffff;
631 #endif // AMD64
632 }
633
634 void os::Linux::set_fpu_control_word(int fpu_control) {
635 #ifndef AMD64
636 _FPU_SETCW(fpu_control);
637 #endif // !AMD64
638 }
639
640 // Check that the linux kernel version is 2.4 or higher since earlier
641 // versions do not support SSE without patches.
642 bool os::supports_sse() {
643 #ifdef AMD64
644 return true;
645 #else
646 struct utsname uts;
647 if( uname(&uts) != 0 ) return false; // uname fails?
648 char *minor_string;
649 int major = strtol(uts.release,&minor_string,10);
650 int minor = strtol(minor_string+1,NULL,10);
651 bool result = (major > 2 || (major==2 && minor >= 4));
652 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2",
653 major,minor, result ? "DOES" : "does NOT");
654 return result;
655 #endif // AMD64
656 }
657
658 bool os::is_allocatable(size_t bytes) {
659 #ifdef AMD64
660 // unused on amd64?
661 return true;
662 #else
663
664 if (bytes < 2 * G) {
665 return true;
666 }
667
668 char* addr = reserve_memory(bytes, NULL);
669
670 if (addr != NULL) {
671 release_memory(addr, bytes);
672 }
673
674 return addr != NULL;
675 #endif // AMD64
676 }
677
678 ////////////////////////////////////////////////////////////////////////////////
679 // thread stack
680
681 // Minimum usable stack sizes required to get to user code. Space for
682 // HotSpot guard pages is added later.
683 size_t os::Posix::_compiler_thread_min_stack_allowed = 48 * K;
684 size_t os::Posix::_java_thread_min_stack_allowed = 40 * K;
685 #ifdef _LP64
686 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
687 #else
688 size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
689 #endif // _LP64
690
691 // return default stack size for thr_type
692 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
693 // default stack size (compiler thread needs larger stack)
694 #ifdef AMD64
695 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
696 #else
697 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
698 #endif // AMD64
699 return s;
700 }
701
702 /////////////////////////////////////////////////////////////////////////////
703 // helper functions for fatal error handler
704
705 void os::print_context(outputStream *st, const void *context) {
706 if (context == NULL) return;
707
708 const ucontext_t *uc = (const ucontext_t*)context;
709 st->print_cr("Registers:");
710 #ifdef AMD64
711 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]);
712 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]);
713 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]);
714 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]);
715 st->cr();
716 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]);
717 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]);
718 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]);
719 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]);
720 st->cr();
721 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]);
722 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]);
723 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]);
724 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]);
725 st->cr();
726 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]);
727 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]);
728 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]);
729 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]);
730 st->cr();
731 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]);
732 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]);
733 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]);
734 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]);
735 st->cr();
736 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]);
737 #else
738 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
739 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
740 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
741 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
742 st->cr();
743 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
744 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
745 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
746 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
747 st->cr();
748 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
749 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
750 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2);
751 #endif // AMD64
752 st->cr();
753 st->cr();
754
755 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
756 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
757 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t));
758 st->cr();
759
760 // Note: it may be unsafe to inspect memory near pc. For example, pc may
761 // point to garbage if entry point in an nmethod is corrupted. Leave
762 // this at the end, and hope for the best.
763 address pc = os::Linux::ucontext_get_pc(uc);
764 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
765 print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
766 }
767
768 void os::print_register_info(outputStream *st, const void *context) {
769 if (context == NULL) return;
770
771 const ucontext_t *uc = (const ucontext_t*)context;
772
773 st->print_cr("Register to memory mapping:");
774 st->cr();
775
776 // this is horrendously verbose but the layout of the registers in the
777 // context does not match how we defined our abstract Register set, so
778 // we can't just iterate through the gregs area
779
780 // this is only for the "general purpose" registers
781
782 #ifdef AMD64
783 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
784 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
785 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
786 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
787 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
788 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
789 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
790 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
791 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
792 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
793 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
794 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
795 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
796 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
797 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
798 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
799 #else
800 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
801 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
802 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
803 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
804 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
805 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
806 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
807 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
808 #endif // AMD64
809
810 st->cr();
811 }
812
813 void os::setup_fpu() {
814 #ifndef AMD64
815 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
816 __asm__ volatile ( "fldcw (%0)" :
817 : "r" (fpu_cntrl) : "memory");
818 #endif // !AMD64
819 }
820
821 #ifndef PRODUCT
822 void os::verify_stack_alignment() {
823 #ifdef AMD64
824 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
825 #endif
826 }
827 #endif
828
829
830 /*
831 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit
832 * updates (JDK-8023956).
833 */
834 void os::workaround_expand_exec_shield_cs_limit() {
835 #if defined(IA32)
836 size_t page_size = os::vm_page_size();
837 /*
838 * Take the highest VA the OS will give us and exec
839 *
840 * Although using -(pagesz) as mmap hint works on newer kernel as you would
841 * think, older variants affected by this work-around don't (search forward only).
842 *
843 * On the affected distributions, we understand the memory layout to be:
844 *
845 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT.
846 *
847 * A few pages south main stack will do it.
848 *
849 * If we are embedded in an app other than launcher (initial != main stack),
850 * we don't have much control or understanding of the address space, just let it slide.
851 */
852 char* hint = (char*)(Linux::initial_thread_stack_bottom() -
853 (JavaThread::stack_guard_zone_size() + page_size));
854 char* codebuf = os::attempt_reserve_memory_at(page_size, hint);
855 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) {
856 return; // No matter, we tried, best effort.
857 }
858
859 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal);
860
861 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf);
862
863 // Some code to exec: the 'ret' instruction
864 codebuf[0] = 0xC3;
865
866 // Call the code in the codebuf
867 __asm__ volatile("call *%0" : : "r"(codebuf));
868
869 // keep the page mapped so CS limit isn't reduced.
870 #endif
871 }
872
873 int os::extra_bang_size_in_bytes() {
874 // JDK-8050147 requires the full cache line bang for x86.
875 return VM_Version::L1_line_size();
876 }