1 /*
2 * Copyright (c) 1999, 2016, 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 "asm/macroAssembler.hpp"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "code/vtableStubs.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "memory/allocation.inline.hpp"
36 #include "mutex_linux.inline.hpp"
37 #include "os_share_linux.hpp"
38 #include "prims/jniFastGetField.hpp"
39 #include "prims/jvm.h"
40 #include "prims/jvm_misc.hpp"
41 #include "runtime/arguments.hpp"
42 #include "runtime/extendedPC.hpp"
43 #include "runtime/frame.inline.hpp"
44 #include "runtime/interfaceSupport.hpp"
45 #include "runtime/java.hpp"
46 #include "runtime/javaCalls.hpp"
47 #include "runtime/mutexLocker.hpp"
48 #include "runtime/osThread.hpp"
49 #include "runtime/sharedRuntime.hpp"
50 #include "runtime/stubRoutines.hpp"
51 #include "runtime/thread.inline.hpp"
52 #include "runtime/timer.hpp"
53 #include "services/memTracker.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 # include <ucontext.h>
77 # include <fpu_control.h>
78
79 #ifdef AMD64
80 #define REG_SP REG_RSP
81 #define REG_PC REG_RIP
82 #define REG_FP REG_RBP
83 #define SPELL_REG_SP "rsp"
84 #define SPELL_REG_FP "rbp"
85 #else
86 #define REG_SP REG_UESP
87 #define REG_PC REG_EIP
88 #define REG_FP REG_EBP
89 #define SPELL_REG_SP "esp"
90 #define SPELL_REG_FP "ebp"
91 #endif // AMD64
92
93 address os::current_stack_pointer() {
94 #ifdef SPARC_WORKS
95 register void *esp;
96 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
97 return (address) ((char*)esp + sizeof(long)*2);
98 #elif defined(__clang__)
99 intptr_t* esp;
100 __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):);
101 return (address) esp;
102 #else
103 register void *esp __asm__ (SPELL_REG_SP);
104 return (address) esp;
105 #endif
106 }
107
108 char* os::non_memory_address_word() {
109 // Must never look like an address returned by reserve_memory,
110 // even in its subfields (as defined by the CPU immediate fields,
111 // if the CPU splits constants across multiple instructions).
112
113 return (char*) -1;
114 }
115
116 void os::initialize_thread(Thread* thr) {
117 // Nothing to do.
118 }
119
120 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
121 return (address)uc->uc_mcontext.gregs[REG_PC];
122 }
123
124 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
125 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc;
126 }
127
128 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
129 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
130 }
131
132 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
133 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
134 }
135
136 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
137 // is currently interrupted by SIGPROF.
138 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
139 // frames. Currently we don't do that on Linux, so it's the same as
140 // os::fetch_frame_from_context().
141 // This method is also used for stack overflow signal handling.
142 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
143 const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
144
145 assert(thread != NULL, "just checking");
146 assert(ret_sp != NULL, "just checking");
147 assert(ret_fp != NULL, "just checking");
148
149 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
150 }
151
152 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
153 intptr_t** ret_sp, intptr_t** ret_fp) {
154
155 ExtendedPC epc;
156 const ucontext_t* uc = (const ucontext_t*)ucVoid;
157
158 if (uc != NULL) {
159 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
160 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
161 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
162 } else {
163 // construct empty ExtendedPC for return value checking
164 epc = ExtendedPC(NULL);
165 if (ret_sp) *ret_sp = (intptr_t *)NULL;
166 if (ret_fp) *ret_fp = (intptr_t *)NULL;
167 }
168
169 return epc;
170 }
171
172 frame os::fetch_frame_from_context(const void* ucVoid) {
173 intptr_t* sp;
174 intptr_t* fp;
175 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
176 return frame(sp, fp, epc.pc());
177 }
178
179 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
180 intptr_t* sp;
181 intptr_t* fp;
182 ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp);
183 return frame(sp, fp, epc.pc());
184 }
185
186 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
187 address pc = (address) os::Linux::ucontext_get_pc(uc);
188 if (Interpreter::contains(pc)) {
189 // interpreter performs stack banging after the fixed frame header has
190 // been generated while the compilers perform it before. To maintain
191 // semantic consistency between interpreted and compiled frames, the
192 // method returns the Java sender of the current frame.
193 *fr = os::fetch_frame_from_ucontext(thread, uc);
194 if (!fr->is_first_java_frame()) {
195 assert(fr->safe_for_sender(thread), "Safety check");
196 *fr = fr->java_sender();
197 }
198 } else {
199 // more complex code with compiled code
200 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
201 CodeBlob* cb = CodeCache::find_blob(pc);
202 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
203 // Not sure where the pc points to, fallback to default
204 // stack overflow handling
205 return false;
206 } else {
207 // in compiled code, the stack banging is performed just after the return pc
208 // has been pushed on the stack
209 intptr_t* fp = os::Linux::ucontext_get_fp(uc);
210 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
211 *fr = frame(sp + 1, fp, (address)*sp);
212 if (!fr->is_java_frame()) {
213 assert(fr->safe_for_sender(thread), "Safety check");
214 assert(!fr->is_first_frame(), "Safety check");
215 *fr = fr->java_sender();
216 }
217 }
218 }
219 assert(fr->is_java_frame(), "Safety check");
220 return true;
221 }
222
223 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
224 // turned off by -fomit-frame-pointer,
225 frame os::get_sender_for_C_frame(frame* fr) {
226 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
227 }
228
229 intptr_t* _get_previous_fp() {
230 #ifdef SPARC_WORKS
231 register intptr_t **ebp;
232 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
233 #elif defined(__clang__)
234 intptr_t **ebp;
235 __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):);
236 #else
237 register intptr_t **ebp __asm__ (SPELL_REG_FP);
238 #endif
239 return (intptr_t*) *ebp; // we want what it points to.
240 }
241
242
243 frame os::current_frame() {
244 intptr_t* fp = _get_previous_fp();
245 frame myframe((intptr_t*)os::current_stack_pointer(),
246 (intptr_t*)fp,
247 CAST_FROM_FN_PTR(address, os::current_frame));
248 if (os::is_first_C_frame(&myframe)) {
249 // stack is not walkable
250 return frame();
251 } else {
252 return os::get_sender_for_C_frame(&myframe);
253 }
254 }
255
256 // Utility functions
257
258 // From IA32 System Programming Guide
259 enum {
260 trap_page_fault = 0xE
261 };
262
263 extern "C" JNIEXPORT int
264 JVM_handle_linux_signal(int sig,
265 siginfo_t* info,
266 void* ucVoid,
267 int abort_if_unrecognized) {
268 ucontext_t* uc = (ucontext_t*) ucVoid;
269
270 Thread* t = Thread::current_or_null_safe();
271
272 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
273 // (no destructors can be run)
274 os::WatcherThreadCrashProtection::check_crash_protection(sig, t);
275
276 SignalHandlerMark shm(t);
277
278 // Note: it's not uncommon that JNI code uses signal/sigset to install
279 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
280 // or have a SIGILL handler when detecting CPU type). When that happens,
281 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
282 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
283 // that do not require siginfo/ucontext first.
284
285 if (sig == SIGPIPE || sig == SIGXFSZ) {
286 // allow chained handler to go first
287 if (os::Linux::chained_handler(sig, info, ucVoid)) {
288 return true;
289 } else {
290 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
291 return true;
292 }
293 }
294
295 JavaThread* thread = NULL;
296 VMThread* vmthread = NULL;
297 if (os::Linux::signal_handlers_are_installed) {
298 if (t != NULL ){
299 if(t->is_Java_thread()) {
300 thread = (JavaThread*)t;
301 }
302 else if(t->is_VM_thread()){
303 vmthread = (VMThread *)t;
304 }
305 }
306 }
307 /*
308 NOTE: does not seem to work on linux.
309 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
310 // can't decode this kind of signal
311 info = NULL;
312 } else {
313 assert(sig == info->si_signo, "bad siginfo");
314 }
315 */
316 // decide if this trap can be handled by a stub
317 address stub = NULL;
318
319 address pc = NULL;
320
321 //%note os_trap_1
322 if (info != NULL && uc != NULL && thread != NULL) {
323 pc = (address) os::Linux::ucontext_get_pc(uc);
324
325 if (StubRoutines::is_safefetch_fault(pc)) {
326 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
327 return 1;
328 }
329
330 #ifndef AMD64
331 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs
332 // This can happen in any running code (currently more frequently in
333 // interpreter code but has been seen in compiled code)
334 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) {
335 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due "
336 "to unstable signal handling in this distribution.");
337 }
338 #endif // AMD64
339
340 // Handle ALL stack overflow variations here
341 if (sig == SIGSEGV) {
342 address addr = (address) info->si_addr;
343
344 // check if fault address is within thread stack
345 if (thread->on_local_stack(addr)) {
346 // stack overflow
347 if (thread->in_stack_yellow_reserved_zone(addr)) {
348 if (thread->thread_state() == _thread_in_Java) {
349 if (thread->in_stack_reserved_zone(addr)) {
350 frame fr;
351 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
352 assert(fr.is_java_frame(), "Must be a Java frame");
353 frame activation =
354 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
355 if (activation.sp() != NULL) {
356 thread->disable_stack_reserved_zone();
357 if (activation.is_interpreted_frame()) {
358 thread->set_reserved_stack_activation((address)(
359 activation.fp() + frame::interpreter_frame_initial_sp_offset));
360 } else {
361 thread->set_reserved_stack_activation((address)activation.unextended_sp());
362 }
363 return 1;
364 }
365 }
366 }
367 // Throw a stack overflow exception. Guard pages will be reenabled
368 // while unwinding the stack.
369 thread->disable_stack_yellow_reserved_zone();
370 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
371 } else {
372 // Thread was in the vm or native code. Return and try to finish.
373 thread->disable_stack_yellow_reserved_zone();
374 return 1;
375 }
376 } else if (thread->in_stack_red_zone(addr)) {
377 // Fatal red zone violation. Disable the guard pages and fall through
378 // to handle_unexpected_exception way down below.
379 thread->disable_stack_red_zone();
380 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
381
382 // This is a likely cause, but hard to verify. Let's just print
383 // it as a hint.
384 tty->print_raw_cr("Please check if any of your loaded .so files has "
385 "enabled executable stack (see man page execstack(8))");
386 } else {
387 // Accessing stack address below sp may cause SEGV if current
388 // thread has MAP_GROWSDOWN stack. This should only happen when
389 // current thread was created by user code with MAP_GROWSDOWN flag
390 // and then attached to VM. See notes in os_linux.cpp.
391 if (thread->osthread()->expanding_stack() == 0) {
392 thread->osthread()->set_expanding_stack();
393 if (os::Linux::manually_expand_stack(thread, addr)) {
394 thread->osthread()->clear_expanding_stack();
395 return 1;
396 }
397 thread->osthread()->clear_expanding_stack();
398 } else {
399 fatal("recursive segv. expanding stack.");
400 }
401 }
402 }
403 }
404
405 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) {
406 // Verify that OS save/restore AVX registers.
407 stub = VM_Version::cpuinfo_cont_addr();
408 }
409
410 if (thread->thread_state() == _thread_in_Java) {
411 // Java thread running in Java code => find exception handler if any
412 // a fault inside compiled code, the interpreter, or a stub
413
414 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
415 stub = SharedRuntime::get_poll_stub(pc);
416 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
417 // BugId 4454115: A read from a MappedByteBuffer can fault
418 // here if the underlying file has been truncated.
419 // Do not crash the VM in such a case.
420 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
421 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
422 if (nm != NULL && nm->has_unsafe_access()) {
423 stub = StubRoutines::handler_for_unsafe_access();
424 }
425 }
426 else
427
428 #ifdef AMD64
429 if (sig == SIGFPE &&
430 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
431 stub =
432 SharedRuntime::
433 continuation_for_implicit_exception(thread,
434 pc,
435 SharedRuntime::
436 IMPLICIT_DIVIDE_BY_ZERO);
437 #else
438 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
439 // HACK: si_code does not work on linux 2.2.12-20!!!
440 int op = pc[0];
441 if (op == 0xDB) {
442 // FIST
443 // TODO: The encoding of D2I in i486.ad can cause an exception
444 // prior to the fist instruction if there was an invalid operation
445 // pending. We want to dismiss that exception. From the win_32
446 // side it also seems that if it really was the fist causing
447 // the exception that we do the d2i by hand with different
448 // rounding. Seems kind of weird.
449 // NOTE: that we take the exception at the NEXT floating point instruction.
450 assert(pc[0] == 0xDB, "not a FIST opcode");
451 assert(pc[1] == 0x14, "not a FIST opcode");
452 assert(pc[2] == 0x24, "not a FIST opcode");
453 return true;
454 } else if (op == 0xF7) {
455 // IDIV
456 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
457 } else {
458 // TODO: handle more cases if we are using other x86 instructions
459 // that can generate SIGFPE signal on linux.
460 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
461 fatal("please update this code.");
462 }
463 #endif // AMD64
464 } else if (sig == SIGSEGV &&
465 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
466 // Determination of interpreter/vtable stub/compiled code null exception
467 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
468 }
469 } else if (thread->thread_state() == _thread_in_vm &&
470 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
471 thread->doing_unsafe_access()) {
472 stub = StubRoutines::handler_for_unsafe_access();
473 }
474
475 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
476 // and the heap gets shrunk before the field access.
477 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
478 address addr = JNI_FastGetField::find_slowcase_pc(pc);
479 if (addr != (address)-1) {
480 stub = addr;
481 }
482 }
483
484 // Check to see if we caught the safepoint code in the
485 // process of write protecting the memory serialization page.
486 // It write enables the page immediately after protecting it
487 // so we can just return to retry the write.
488 if ((sig == SIGSEGV) &&
489 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
490 // Block current thread until the memory serialize page permission restored.
491 os::block_on_serialize_page_trap();
492 return true;
493 }
494 }
495
496 #ifndef AMD64
497 // Execution protection violation
498 //
499 // This should be kept as the last step in the triage. We don't
500 // have a dedicated trap number for a no-execute fault, so be
501 // conservative and allow other handlers the first shot.
502 //
503 // Note: We don't test that info->si_code == SEGV_ACCERR here.
504 // this si_code is so generic that it is almost meaningless; and
505 // the si_code for this condition may change in the future.
506 // Furthermore, a false-positive should be harmless.
507 if (UnguardOnExecutionViolation > 0 &&
508 (sig == SIGSEGV || sig == SIGBUS) &&
509 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
510 int page_size = os::vm_page_size();
511 address addr = (address) info->si_addr;
512 address pc = os::Linux::ucontext_get_pc(uc);
513 // Make sure the pc and the faulting address are sane.
514 //
515 // If an instruction spans a page boundary, and the page containing
516 // the beginning of the instruction is executable but the following
517 // page is not, the pc and the faulting address might be slightly
518 // different - we still want to unguard the 2nd page in this case.
519 //
520 // 15 bytes seems to be a (very) safe value for max instruction size.
521 bool pc_is_near_addr =
522 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
523 bool instr_spans_page_boundary =
524 (align_size_down((intptr_t) pc ^ (intptr_t) addr,
525 (intptr_t) page_size) > 0);
526
527 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
528 static volatile address last_addr =
529 (address) os::non_memory_address_word();
530
531 // In conservative mode, don't unguard unless the address is in the VM
532 if (addr != last_addr &&
533 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
534
535 // Set memory to RWX and retry
536 address page_start =
537 (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
538 bool res = os::protect_memory((char*) page_start, page_size,
539 os::MEM_PROT_RWX);
540
541 log_debug(os)("Execution protection violation "
542 "at " INTPTR_FORMAT
543 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
544 p2i(page_start), (res ? "success" : "failed"), errno);
545 stub = pc;
546
547 // Set last_addr so if we fault again at the same address, we don't end
548 // up in an endless loop.
549 //
550 // There are two potential complications here. Two threads trapping at
551 // the same address at the same time could cause one of the threads to
552 // think it already unguarded, and abort the VM. Likely very rare.
553 //
554 // The other race involves two threads alternately trapping at
555 // different addresses and failing to unguard the page, resulting in
556 // an endless loop. This condition is probably even more unlikely than
557 // the first.
558 //
559 // Although both cases could be avoided by using locks or thread local
560 // last_addr, these solutions are unnecessary complication: this
561 // handler is a best-effort safety net, not a complete solution. It is
562 // disabled by default and should only be used as a workaround in case
563 // we missed any no-execute-unsafe VM code.
564
565 last_addr = addr;
566 }
567 }
568 }
569 #endif // !AMD64
570
571 if (stub != NULL) {
572 // save all thread context in case we need to restore it
573 if (thread != NULL) thread->set_saved_exception_pc(pc);
574
575 os::Linux::ucontext_set_pc(uc, stub);
576 return true;
577 }
578
579 // signal-chaining
580 if (os::Linux::chained_handler(sig, info, ucVoid)) {
581 return true;
582 }
583
584 if (!abort_if_unrecognized) {
585 // caller wants another chance, so give it to him
586 return false;
587 }
588
589 if (pc == NULL && uc != NULL) {
590 pc = os::Linux::ucontext_get_pc(uc);
591 }
592
593 // unmask current signal
594 sigset_t newset;
595 sigemptyset(&newset);
596 sigaddset(&newset, sig);
597 sigprocmask(SIG_UNBLOCK, &newset, NULL);
598
599 VMError::report_and_die(t, sig, pc, info, ucVoid);
600
601 ShouldNotReachHere();
602 return true; // Mute compiler
603 }
604
605 void os::Linux::init_thread_fpu_state(void) {
606 #ifndef AMD64
607 // set fpu to 53 bit precision
608 set_fpu_control_word(0x27f);
609 #endif // !AMD64
610 }
611
612 int os::Linux::get_fpu_control_word(void) {
613 #ifdef AMD64
614 return 0;
615 #else
616 int fpu_control;
617 _FPU_GETCW(fpu_control);
618 return fpu_control & 0xffff;
619 #endif // AMD64
620 }
621
622 void os::Linux::set_fpu_control_word(int fpu_control) {
623 #ifndef AMD64
624 _FPU_SETCW(fpu_control);
625 #endif // !AMD64
626 }
627
628 // Check that the linux kernel version is 2.4 or higher since earlier
629 // versions do not support SSE without patches.
630 bool os::supports_sse() {
631 #ifdef AMD64
632 return true;
633 #else
634 struct utsname uts;
635 if( uname(&uts) != 0 ) return false; // uname fails?
636 char *minor_string;
637 int major = strtol(uts.release,&minor_string,10);
638 int minor = strtol(minor_string+1,NULL,10);
639 bool result = (major > 2 || (major==2 && minor >= 4));
640 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2",
641 major,minor, result ? "DOES" : "does NOT");
642 return result;
643 #endif // AMD64
644 }
645
646 bool os::is_allocatable(size_t bytes) {
647 #ifdef AMD64
648 // unused on amd64?
649 return true;
650 #else
651
652 if (bytes < 2 * G) {
653 return true;
654 }
655
656 char* addr = reserve_memory(bytes, NULL);
657
658 if (addr != NULL) {
659 release_memory(addr, bytes);
660 }
661
662 return addr != NULL;
663 #endif // AMD64
664 }
665
666 ////////////////////////////////////////////////////////////////////////////////
667 // thread stack
668
669 #ifdef AMD64
670 size_t os::Linux::min_stack_allowed = 64 * K;
671 #else
672 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K;
673 #endif // AMD64
674
675 // return default stack size for thr_type
676 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
677 // default stack size (compiler thread needs larger stack)
678 #ifdef AMD64
679 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
680 #else
681 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
682 #endif // AMD64
683 return s;
684 }
685
686 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
687 // Creating guard page is very expensive. Java thread has HotSpot
688 // guard page, only enable glibc guard page for non-Java threads.
689 return (thr_type == java_thread ? 0 : page_size());
690 }
691
692 // Java thread:
693 //
694 // Low memory addresses
695 // +------------------------+
696 // | |\ JavaThread created by VM does not have glibc
697 // | glibc guard page | - guard, attached Java thread usually has
698 // | |/ 1 page glibc guard.
699 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
700 // | |\
701 // | HotSpot Guard Pages | - red and yellow pages
702 // | |/
703 // +------------------------+ JavaThread::stack_yellow_zone_base()
704 // | |\
705 // | Normal Stack | -
706 // | |/
707 // P2 +------------------------+ Thread::stack_base()
708 //
709 // Non-Java thread:
710 //
711 // Low memory addresses
712 // +------------------------+
713 // | |\
714 // | glibc guard page | - usually 1 page
715 // | |/
716 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
717 // | |\
718 // | Normal Stack | -
719 // | |/
720 // P2 +------------------------+ Thread::stack_base()
721 //
722 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
723 // pthread_attr_getstack()
724
725 static void current_stack_region(address * bottom, size_t * size) {
726 if (os::Linux::is_initial_thread()) {
727 // initial thread needs special handling because pthread_getattr_np()
728 // may return bogus value.
729 *bottom = os::Linux::initial_thread_stack_bottom();
730 *size = os::Linux::initial_thread_stack_size();
731 } else {
732 pthread_attr_t attr;
733
734 int rslt = pthread_getattr_np(pthread_self(), &attr);
735
736 // JVM needs to know exact stack location, abort if it fails
737 if (rslt != 0) {
738 if (rslt == ENOMEM) {
739 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
740 } else {
741 fatal("pthread_getattr_np failed with errno = %d", rslt);
742 }
743 }
744
745 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
746 fatal("Can not locate current stack attributes!");
747 }
748
749 pthread_attr_destroy(&attr);
750
751 }
752 assert(os::current_stack_pointer() >= *bottom &&
753 os::current_stack_pointer() < *bottom + *size, "just checking");
754 }
755
756 address os::current_stack_base() {
757 address bottom;
758 size_t size;
759 current_stack_region(&bottom, &size);
760 return (bottom + size);
761 }
762
763 size_t os::current_stack_size() {
764 // stack size includes normal stack and HotSpot guard pages
765 address bottom;
766 size_t size;
767 current_stack_region(&bottom, &size);
768 return size;
769 }
770
771 /////////////////////////////////////////////////////////////////////////////
772 // helper functions for fatal error handler
773
774 void os::print_context(outputStream *st, const void *context) {
775 if (context == NULL) return;
776
777 const ucontext_t *uc = (const ucontext_t*)context;
778 st->print_cr("Registers:");
779 #ifdef AMD64
780 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]);
781 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]);
782 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]);
783 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]);
784 st->cr();
785 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]);
786 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]);
787 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]);
788 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]);
789 st->cr();
790 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]);
791 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]);
792 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]);
793 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]);
794 st->cr();
795 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]);
796 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]);
797 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]);
798 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]);
799 st->cr();
800 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]);
801 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]);
802 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]);
803 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]);
804 st->cr();
805 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]);
806 #else
807 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
808 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
809 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
810 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
811 st->cr();
812 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
813 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
814 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
815 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
816 st->cr();
817 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
818 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
819 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2);
820 #endif // AMD64
821 st->cr();
822 st->cr();
823
824 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
825 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
826 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t));
827 st->cr();
828
829 // Note: it may be unsafe to inspect memory near pc. For example, pc may
830 // point to garbage if entry point in an nmethod is corrupted. Leave
831 // this at the end, and hope for the best.
832 address pc = os::Linux::ucontext_get_pc(uc);
833 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
834 print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
835 }
836
837 void os::print_register_info(outputStream *st, const void *context) {
838 if (context == NULL) return;
839
840 const ucontext_t *uc = (const ucontext_t*)context;
841
842 st->print_cr("Register to memory mapping:");
843 st->cr();
844
845 // this is horrendously verbose but the layout of the registers in the
846 // context does not match how we defined our abstract Register set, so
847 // we can't just iterate through the gregs area
848
849 // this is only for the "general purpose" registers
850
851 #ifdef AMD64
852 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
853 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
854 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
855 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
856 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
857 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
858 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
859 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
860 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
861 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
862 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
863 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
864 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
865 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
866 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
867 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
868 #else
869 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
870 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
871 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
872 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
873 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
874 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
875 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
876 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
877 #endif // AMD64
878
879 st->cr();
880 }
881
882 void os::setup_fpu() {
883 #ifndef AMD64
884 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
885 __asm__ volatile ( "fldcw (%0)" :
886 : "r" (fpu_cntrl) : "memory");
887 #endif // !AMD64
888 }
889
890 #ifndef PRODUCT
891 void os::verify_stack_alignment() {
892 #ifdef AMD64
893 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
894 #endif
895 }
896 #endif
897
898
899 /*
900 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit
901 * updates (JDK-8023956).
902 */
903 void os::workaround_expand_exec_shield_cs_limit() {
904 #if defined(IA32)
905 size_t page_size = os::vm_page_size();
906 /*
907 * Take the highest VA the OS will give us and exec
908 *
909 * Although using -(pagesz) as mmap hint works on newer kernel as you would
910 * think, older variants affected by this work-around don't (search forward only).
911 *
912 * On the affected distributions, we understand the memory layout to be:
913 *
914 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT.
915 *
916 * A few pages south main stack will do it.
917 *
918 * If we are embedded in an app other than launcher (initial != main stack),
919 * we don't have much control or understanding of the address space, just let it slide.
920 */
921 char* hint = (char*)(Linux::initial_thread_stack_bottom() -
922 (JavaThread::stack_guard_zone_size() + page_size));
923 char* codebuf = os::attempt_reserve_memory_at(page_size, hint);
924 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) {
925 return; // No matter, we tried, best effort.
926 }
927
928 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal);
929
930 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf);
931
932 // Some code to exec: the 'ret' instruction
933 codebuf[0] = 0xC3;
934
935 // Call the code in the codebuf
936 __asm__ volatile("call *%0" : : "r"(codebuf));
937
938 // keep the page mapped so CS limit isn't reduced.
939 #endif
940 }
941
942 int os::extra_bang_size_in_bytes() {
943 // JDK-8050147 requires the full cache line bang for x86.
944 return VM_Version::L1_line_size();
945 }