1 /*
2 * Copyright (c) 1999, 2012, 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/icBuffer.hpp"
31 #include "code/vtableStubs.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "jvm_linux.h"
34 #include "memory/allocation.inline.hpp"
35 #include "mutex_linux.inline.hpp"
36 #include "os_share_linux.hpp"
37 #include "prims/jniFastGetField.hpp"
38 #include "prims/jvm.h"
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.hpp"
44 #include "runtime/java.hpp"
45 #include "runtime/javaCalls.hpp"
46 #include "runtime/mutexLocker.hpp"
47 #include "runtime/osThread.hpp"
48 #include "runtime/sharedRuntime.hpp"
49 #include "runtime/stubRoutines.hpp"
50 #include "runtime/thread.inline.hpp"
51 #include "runtime/timer.hpp"
52 #include "utilities/events.hpp"
53 #include "utilities/vmError.hpp"
54
55 // put OS-includes here
56 # include <sys/types.h>
57 # include <sys/mman.h>
58 # include <pthread.h>
59 # include <signal.h>
60 # include <errno.h>
61 # include <dlfcn.h>
62 # include <stdlib.h>
63 # include <stdio.h>
64 # include <unistd.h>
65 # include <sys/resource.h>
66 # include <pthread.h>
67 # include <sys/stat.h>
68 # include <sys/time.h>
69 # include <sys/utsname.h>
70 # include <sys/socket.h>
71 # include <sys/wait.h>
72 # include <pwd.h>
73 # include <poll.h>
74 # include <ucontext.h>
75 # include <fpu_control.h>
76
77 #ifdef AMD64
78 #define REG_SP REG_RSP
79 #define REG_PC REG_RIP
80 #define REG_FP REG_RBP
81 #define SPELL_REG_SP "rsp"
82 #define SPELL_REG_FP "rbp"
83 #else
84 #define REG_SP REG_UESP
85 #define REG_PC REG_EIP
86 #define REG_FP REG_EBP
87 #define SPELL_REG_SP "esp"
88 #define SPELL_REG_FP "ebp"
89 #endif // AMD64
90
91 address os::current_stack_pointer() {
92 #ifdef SPARC_WORKS
93 register void *esp;
94 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
95 return (address) ((char*)esp + sizeof(long)*2);
96 #else
97 register void *esp __asm__ (SPELL_REG_SP);
98 return (address) esp;
99 #endif
100 }
101
102 char* os::non_memory_address_word() {
103 // Must never look like an address returned by reserve_memory,
104 // even in its subfields (as defined by the CPU immediate fields,
105 // if the CPU splits constants across multiple instructions).
106
107 return (char*) -1;
108 }
109
110 void os::initialize_thread(Thread* thr) {
111 // Nothing to do.
112 }
113
114 address os::Linux::ucontext_get_pc(ucontext_t * uc) {
115 return (address)uc->uc_mcontext.gregs[REG_PC];
116 }
117
118 intptr_t* os::Linux::ucontext_get_sp(ucontext_t * uc) {
119 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
120 }
121
122 intptr_t* os::Linux::ucontext_get_fp(ucontext_t * uc) {
123 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
124 }
125
126 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
127 // is currently interrupted by SIGPROF.
128 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
129 // frames. Currently we don't do that on Linux, so it's the same as
130 // os::fetch_frame_from_context().
131 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
132 ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
133
134 assert(thread != NULL, "just checking");
135 assert(ret_sp != NULL, "just checking");
136 assert(ret_fp != NULL, "just checking");
137
138 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
139 }
140
141 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
142 intptr_t** ret_sp, intptr_t** ret_fp) {
143
144 ExtendedPC epc;
145 ucontext_t* uc = (ucontext_t*)ucVoid;
146
147 if (uc != NULL) {
148 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
149 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
150 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
151 } else {
152 // construct empty ExtendedPC for return value checking
153 epc = ExtendedPC(NULL);
154 if (ret_sp) *ret_sp = (intptr_t *)NULL;
155 if (ret_fp) *ret_fp = (intptr_t *)NULL;
156 }
157
158 return epc;
159 }
160
161 frame os::fetch_frame_from_context(void* ucVoid) {
162 intptr_t* sp;
163 intptr_t* fp;
164 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
165 return frame(sp, fp, epc.pc());
166 }
167
168 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
169 // turned off by -fomit-frame-pointer,
170 frame os::get_sender_for_C_frame(frame* fr) {
171 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
172 }
173
174 intptr_t* _get_previous_fp() {
175 #ifdef SPARC_WORKS
176 register intptr_t **ebp;
177 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
178 #else
179 register intptr_t **ebp __asm__ (SPELL_REG_FP);
180 #endif
181 return (intptr_t*) *ebp; // we want what it points to.
182 }
183
184
185 frame os::current_frame() {
186 intptr_t* fp = _get_previous_fp();
187 frame myframe((intptr_t*)os::current_stack_pointer(),
188 (intptr_t*)fp,
189 CAST_FROM_FN_PTR(address, os::current_frame));
190 if (os::is_first_C_frame(&myframe)) {
191 // stack is not walkable
192 return frame();
193 } else {
194 return os::get_sender_for_C_frame(&myframe);
195 }
196 }
197
198 // Utility functions
199
200 // From IA32 System Programming Guide
201 enum {
202 trap_page_fault = 0xE
203 };
204
205 extern "C" void Fetch32PFI () ;
206 extern "C" void Fetch32Resume () ;
207 #ifdef AMD64
208 extern "C" void FetchNPFI () ;
209 extern "C" void FetchNResume () ;
210 #endif // AMD64
211
212 extern "C" JNIEXPORT int
213 JVM_handle_linux_signal(int sig,
214 siginfo_t* info,
215 void* ucVoid,
216 int abort_if_unrecognized) {
217 ucontext_t* uc = (ucontext_t*) ucVoid;
218
219 Thread* t = ThreadLocalStorage::get_thread_slow();
220
221 SignalHandlerMark shm(t);
222
223 // Note: it's not uncommon that JNI code uses signal/sigset to install
224 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
225 // or have a SIGILL handler when detecting CPU type). When that happens,
226 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
227 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
228 // that do not require siginfo/ucontext first.
229
230 if (sig == SIGPIPE || sig == SIGXFSZ) {
231 // allow chained handler to go first
232 if (os::Linux::chained_handler(sig, info, ucVoid)) {
233 return true;
234 } else {
235 if (PrintMiscellaneous && (WizardMode || Verbose)) {
236 char buf[64];
237 warning("Ignoring %s - see bugs 4229104 or 646499219",
238 os::exception_name(sig, buf, sizeof(buf)));
239 }
240 return true;
241 }
242 }
243
244 JavaThread* thread = NULL;
245 VMThread* vmthread = NULL;
246 if (os::Linux::signal_handlers_are_installed) {
247 if (t != NULL ){
248 if(t->is_Java_thread()) {
249 thread = (JavaThread*)t;
250 }
251 else if(t->is_VM_thread()){
252 vmthread = (VMThread *)t;
253 }
254 }
255 }
256 /*
257 NOTE: does not seem to work on linux.
258 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
259 // can't decode this kind of signal
260 info = NULL;
261 } else {
262 assert(sig == info->si_signo, "bad siginfo");
263 }
264 */
265 // decide if this trap can be handled by a stub
266 address stub = NULL;
267
268 address pc = NULL;
269
270 //%note os_trap_1
271 if (info != NULL && uc != NULL && thread != NULL) {
272 pc = (address) os::Linux::ucontext_get_pc(uc);
273
274 if (pc == (address) Fetch32PFI) {
275 uc->uc_mcontext.gregs[REG_PC] = intptr_t(Fetch32Resume) ;
276 return 1 ;
277 }
278 #ifdef AMD64
279 if (pc == (address) FetchNPFI) {
280 uc->uc_mcontext.gregs[REG_PC] = intptr_t (FetchNResume) ;
281 return 1 ;
282 }
283 #endif // AMD64
284
285 // Handle ALL stack overflow variations here
286 if (sig == SIGSEGV) {
287 address addr = (address) info->si_addr;
288
289 // check if fault address is within thread stack
290 if (addr < thread->stack_base() &&
291 addr >= thread->stack_base() - thread->stack_size()) {
292 // stack overflow
293 if (thread->in_stack_yellow_zone(addr)) {
294 thread->disable_stack_yellow_zone();
295 if (thread->thread_state() == _thread_in_Java) {
296 // Throw a stack overflow exception. Guard pages will be reenabled
297 // while unwinding the stack.
298 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
299 } else {
300 // Thread was in the vm or native code. Return and try to finish.
301 return 1;
302 }
303 } else if (thread->in_stack_red_zone(addr)) {
304 // Fatal red zone violation. Disable the guard pages and fall through
305 // to handle_unexpected_exception way down below.
306 thread->disable_stack_red_zone();
307 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
308
309 // This is a likely cause, but hard to verify. Let's just print
310 // it as a hint.
311 tty->print_raw_cr("Please check if any of your loaded .so files has "
312 "enabled executable stack (see man page execstack(8))");
313 } else {
314 // Accessing stack address below sp may cause SEGV if current
315 // thread has MAP_GROWSDOWN stack. This should only happen when
316 // current thread was created by user code with MAP_GROWSDOWN flag
317 // and then attached to VM. See notes in os_linux.cpp.
318 if (thread->osthread()->expanding_stack() == 0) {
319 thread->osthread()->set_expanding_stack();
320 if (os::Linux::manually_expand_stack(thread, addr)) {
321 thread->osthread()->clear_expanding_stack();
322 return 1;
323 }
324 thread->osthread()->clear_expanding_stack();
325 } else {
326 fatal("recursive segv. expanding stack.");
327 }
328 }
329 }
330 }
331
332 if (thread->thread_state() == _thread_in_Java) {
333 // Java thread running in Java code => find exception handler if any
334 // a fault inside compiled code, the interpreter, or a stub
335
336 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
337 stub = SharedRuntime::get_poll_stub(pc);
338 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
339 // BugId 4454115: A read from a MappedByteBuffer can fault
340 // here if the underlying file has been truncated.
341 // Do not crash the VM in such a case.
342 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
343 nmethod* nm = (cb != NULL && cb->is_nmethod()) ? (nmethod*)cb : NULL;
344 if (nm != NULL && nm->has_unsafe_access()) {
345 stub = StubRoutines::handler_for_unsafe_access();
346 }
347 }
348 else
349
350 #ifdef AMD64
351 if (sig == SIGFPE &&
352 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
353 stub =
354 SharedRuntime::
355 continuation_for_implicit_exception(thread,
356 pc,
357 SharedRuntime::
358 IMPLICIT_DIVIDE_BY_ZERO);
359 #else
360 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
361 // HACK: si_code does not work on linux 2.2.12-20!!!
362 int op = pc[0];
363 if (op == 0xDB) {
364 // FIST
365 // TODO: The encoding of D2I in i486.ad can cause an exception
366 // prior to the fist instruction if there was an invalid operation
367 // pending. We want to dismiss that exception. From the win_32
368 // side it also seems that if it really was the fist causing
369 // the exception that we do the d2i by hand with different
370 // rounding. Seems kind of weird.
371 // NOTE: that we take the exception at the NEXT floating point instruction.
372 assert(pc[0] == 0xDB, "not a FIST opcode");
373 assert(pc[1] == 0x14, "not a FIST opcode");
374 assert(pc[2] == 0x24, "not a FIST opcode");
375 return true;
376 } else if (op == 0xF7) {
377 // IDIV
378 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
379 } else {
380 // TODO: handle more cases if we are using other x86 instructions
381 // that can generate SIGFPE signal on linux.
382 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
383 fatal("please update this code.");
384 }
385 #endif // AMD64
386 } else if (sig == SIGSEGV &&
387 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
388 // Determination of interpreter/vtable stub/compiled code null exception
389 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
390 }
391 } else if (thread->thread_state() == _thread_in_vm &&
392 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
393 thread->doing_unsafe_access()) {
394 stub = StubRoutines::handler_for_unsafe_access();
395 }
396
397 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
398 // and the heap gets shrunk before the field access.
399 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
400 address addr = JNI_FastGetField::find_slowcase_pc(pc);
401 if (addr != (address)-1) {
402 stub = addr;
403 }
404 }
405
406 // Check to see if we caught the safepoint code in the
407 // process of write protecting the memory serialization page.
408 // It write enables the page immediately after protecting it
409 // so we can just return to retry the write.
410 if ((sig == SIGSEGV) &&
411 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
412 // Block current thread until the memory serialize page permission restored.
413 os::block_on_serialize_page_trap();
414 return true;
415 }
416 }
417
418 #ifndef AMD64
419 // Execution protection violation
420 //
421 // This should be kept as the last step in the triage. We don't
422 // have a dedicated trap number for a no-execute fault, so be
423 // conservative and allow other handlers the first shot.
424 //
425 // Note: We don't test that info->si_code == SEGV_ACCERR here.
426 // this si_code is so generic that it is almost meaningless; and
427 // the si_code for this condition may change in the future.
428 // Furthermore, a false-positive should be harmless.
429 if (UnguardOnExecutionViolation > 0 &&
430 (sig == SIGSEGV || sig == SIGBUS) &&
431 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
432 int page_size = os::vm_page_size();
433 address addr = (address) info->si_addr;
434 address pc = os::Linux::ucontext_get_pc(uc);
435 // Make sure the pc and the faulting address are sane.
436 //
437 // If an instruction spans a page boundary, and the page containing
438 // the beginning of the instruction is executable but the following
439 // page is not, the pc and the faulting address might be slightly
440 // different - we still want to unguard the 2nd page in this case.
441 //
442 // 15 bytes seems to be a (very) safe value for max instruction size.
443 bool pc_is_near_addr =
444 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
445 bool instr_spans_page_boundary =
446 (align_size_down((intptr_t) pc ^ (intptr_t) addr,
447 (intptr_t) page_size) > 0);
448
449 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
450 static volatile address last_addr =
451 (address) os::non_memory_address_word();
452
453 // In conservative mode, don't unguard unless the address is in the VM
454 if (addr != last_addr &&
455 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
456
457 // Set memory to RWX and retry
458 address page_start =
459 (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
460 bool res = os::protect_memory((char*) page_start, page_size,
461 os::MEM_PROT_RWX);
462
463 if (PrintMiscellaneous && Verbose) {
464 char buf[256];
465 jio_snprintf(buf, sizeof(buf), "Execution protection violation "
466 "at " INTPTR_FORMAT
467 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,
468 page_start, (res ? "success" : "failed"), errno);
469 tty->print_raw_cr(buf);
470 }
471 stub = pc;
472
473 // Set last_addr so if we fault again at the same address, we don't end
474 // up in an endless loop.
475 //
476 // There are two potential complications here. Two threads trapping at
477 // the same address at the same time could cause one of the threads to
478 // think it already unguarded, and abort the VM. Likely very rare.
479 //
480 // The other race involves two threads alternately trapping at
481 // different addresses and failing to unguard the page, resulting in
482 // an endless loop. This condition is probably even more unlikely than
483 // the first.
484 //
485 // Although both cases could be avoided by using locks or thread local
486 // last_addr, these solutions are unnecessary complication: this
487 // handler is a best-effort safety net, not a complete solution. It is
488 // disabled by default and should only be used as a workaround in case
489 // we missed any no-execute-unsafe VM code.
490
491 last_addr = addr;
492 }
493 }
494 }
495 #endif // !AMD64
496
497 if (stub != NULL) {
498 // save all thread context in case we need to restore it
499 if (thread != NULL) thread->set_saved_exception_pc(pc);
500
501 uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub;
502 return true;
503 }
504
505 // signal-chaining
506 if (os::Linux::chained_handler(sig, info, ucVoid)) {
507 return true;
508 }
509
510 if (!abort_if_unrecognized) {
511 // caller wants another chance, so give it to him
512 return false;
513 }
514
515 if (pc == NULL && uc != NULL) {
516 pc = os::Linux::ucontext_get_pc(uc);
517 }
518
519 // unmask current signal
520 sigset_t newset;
521 sigemptyset(&newset);
522 sigaddset(&newset, sig);
523 sigprocmask(SIG_UNBLOCK, &newset, NULL);
524
525 VMError err(t, sig, pc, info, ucVoid);
526 err.report_and_die();
527
528 ShouldNotReachHere();
529 }
530
531 void os::Linux::init_thread_fpu_state(void) {
532 #ifndef AMD64
533 // set fpu to 53 bit precision
534 set_fpu_control_word(0x27f);
535 #endif // !AMD64
536 }
537
538 int os::Linux::get_fpu_control_word(void) {
539 #ifdef AMD64
540 return 0;
541 #else
542 int fpu_control;
543 _FPU_GETCW(fpu_control);
544 return fpu_control & 0xffff;
545 #endif // AMD64
546 }
547
548 void os::Linux::set_fpu_control_word(int fpu_control) {
549 #ifndef AMD64
550 _FPU_SETCW(fpu_control);
551 #endif // !AMD64
552 }
553
554 // Check that the linux kernel version is 2.4 or higher since earlier
555 // versions do not support SSE without patches.
556 bool os::supports_sse() {
557 #ifdef AMD64
558 return true;
559 #else
560 struct utsname uts;
561 if( uname(&uts) != 0 ) return false; // uname fails?
562 char *minor_string;
563 int major = strtol(uts.release,&minor_string,10);
564 int minor = strtol(minor_string+1,NULL,10);
565 bool result = (major > 2 || (major==2 && minor >= 4));
566 #ifndef PRODUCT
567 if (PrintMiscellaneous && Verbose) {
568 tty->print("OS version is %d.%d, which %s support SSE/SSE2\n",
569 major,minor, result ? "DOES" : "does NOT");
570 }
571 #endif
572 return result;
573 #endif // AMD64
574 }
575
576 bool os::is_allocatable(size_t bytes) {
577 #ifdef AMD64
578 // unused on amd64?
579 return true;
580 #else
581
582 if (bytes < 2 * G) {
583 return true;
584 }
585
586 char* addr = reserve_memory(bytes, NULL);
587
588 if (addr != NULL) {
589 release_memory(addr, bytes);
590 }
591
592 return addr != NULL;
593 #endif // AMD64
594 }
595
596 ////////////////////////////////////////////////////////////////////////////////
597 // thread stack
598
599 #ifdef AMD64
600 size_t os::Linux::min_stack_allowed = 64 * K;
601
602 // amd64: pthread on amd64 is always in floating stack mode
603 bool os::Linux::supports_variable_stack_size() { return true; }
604 #else
605 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K;
606
607 #ifdef __GNUC__
608 #define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})
609 #endif
610
611 // Test if pthread library can support variable thread stack size. LinuxThreads
612 // in fixed stack mode allocates 2M fixed slot for each thread. LinuxThreads
613 // in floating stack mode and NPTL support variable stack size.
614 bool os::Linux::supports_variable_stack_size() {
615 if (os::Linux::is_NPTL()) {
616 // NPTL, yes
617 return true;
618
619 } else {
620 // Note: We can't control default stack size when creating a thread.
621 // If we use non-default stack size (pthread_attr_setstacksize), both
622 // floating stack and non-floating stack LinuxThreads will return the
623 // same value. This makes it impossible to implement this function by
624 // detecting thread stack size directly.
625 //
626 // An alternative approach is to check %gs. Fixed-stack LinuxThreads
627 // do not use %gs, so its value is 0. Floating-stack LinuxThreads use
628 // %gs (either as LDT selector or GDT selector, depending on kernel)
629 // to access thread specific data.
630 //
631 // Note that %gs is a reserved glibc register since early 2001, so
632 // applications are not allowed to change its value (Ulrich Drepper from
633 // Redhat confirmed that all known offenders have been modified to use
634 // either %fs or TSD). In the worst case scenario, when VM is embedded in
635 // a native application that plays with %gs, we might see non-zero %gs
636 // even LinuxThreads is running in fixed stack mode. As the result, we'll
637 // return true and skip _thread_safety_check(), so we may not be able to
638 // detect stack-heap collisions. But otherwise it's harmless.
639 //
640 #ifdef __GNUC__
641 return (GET_GS() != 0);
642 #else
643 return false;
644 #endif
645 }
646 }
647 #endif // AMD64
648
649 // return default stack size for thr_type
650 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
651 // default stack size (compiler thread needs larger stack)
652 #ifdef AMD64
653 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
654 #else
655 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
656 #endif // AMD64
657 return s;
658 }
659
660 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
661 // Creating guard page is very expensive. Java thread has HotSpot
662 // guard page, only enable glibc guard page for non-Java threads.
663 return (thr_type == java_thread ? 0 : page_size());
664 }
665
666 // Java thread:
667 //
668 // Low memory addresses
669 // +------------------------+
670 // | |\ JavaThread created by VM does not have glibc
671 // | glibc guard page | - guard, attached Java thread usually has
672 // | |/ 1 page glibc guard.
673 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
674 // | |\
675 // | HotSpot Guard Pages | - red and yellow pages
676 // | |/
677 // +------------------------+ JavaThread::stack_yellow_zone_base()
678 // | |\
679 // | Normal Stack | -
680 // | |/
681 // P2 +------------------------+ Thread::stack_base()
682 //
683 // Non-Java thread:
684 //
685 // Low memory addresses
686 // +------------------------+
687 // | |\
688 // | glibc guard page | - usually 1 page
689 // | |/
690 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
691 // | |\
692 // | Normal Stack | -
693 // | |/
694 // P2 +------------------------+ Thread::stack_base()
695 //
696 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
697 // pthread_attr_getstack()
698
699 static void current_stack_region(address * bottom, size_t * size) {
700 if (os::Linux::is_initial_thread()) {
701 // initial thread needs special handling because pthread_getattr_np()
702 // may return bogus value.
703 *bottom = os::Linux::initial_thread_stack_bottom();
704 *size = os::Linux::initial_thread_stack_size();
705 } else {
706 pthread_attr_t attr;
707
708 int rslt = pthread_getattr_np(pthread_self(), &attr);
709
710 // JVM needs to know exact stack location, abort if it fails
711 if (rslt != 0) {
712 if (rslt == ENOMEM) {
713 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
714 } else {
715 fatal(err_msg("pthread_getattr_np failed with errno = %d", rslt));
716 }
717 }
718
719 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
720 fatal("Can not locate current stack attributes!");
721 }
722
723 pthread_attr_destroy(&attr);
724
725 }
726 assert(os::current_stack_pointer() >= *bottom &&
727 os::current_stack_pointer() < *bottom + *size, "just checking");
728 }
729
730 address os::current_stack_base() {
731 address bottom;
732 size_t size;
733 current_stack_region(&bottom, &size);
734 return (bottom + size);
735 }
736
737 size_t os::current_stack_size() {
738 // stack size includes normal stack and HotSpot guard pages
739 address bottom;
740 size_t size;
741 current_stack_region(&bottom, &size);
742 return size;
743 }
744
745 /////////////////////////////////////////////////////////////////////////////
746 // helper functions for fatal error handler
747
748 void os::print_context(outputStream *st, void *context) {
749 if (context == NULL) return;
750
751 ucontext_t *uc = (ucontext_t*)context;
752 st->print_cr("Registers:");
753 #ifdef AMD64
754 st->print( "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
755 st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
756 st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
757 st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
758 st->cr();
759 st->print( "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
760 st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
761 st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
762 st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
763 st->cr();
764 st->print( "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
765 st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
766 st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
767 st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
768 st->cr();
769 st->print( "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
770 st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
771 st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
772 st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
773 st->cr();
774 st->print( "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
775 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
776 st->print(", CSGSFS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_CSGSFS]);
777 st->print(", ERR=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ERR]);
778 st->cr();
779 st->print(" TRAPNO=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_TRAPNO]);
780 #else
781 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
782 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
783 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
784 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
785 st->cr();
786 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
787 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
788 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
789 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
790 st->cr();
791 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
792 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
793 st->print(", CR2=" INTPTR_FORMAT, uc->uc_mcontext.cr2);
794 #endif // AMD64
795 st->cr();
796 st->cr();
797
798 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
799 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
800 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
801 st->cr();
802
803 // Note: it may be unsafe to inspect memory near pc. For example, pc may
804 // point to garbage if entry point in an nmethod is corrupted. Leave
805 // this at the end, and hope for the best.
806 address pc = os::Linux::ucontext_get_pc(uc);
807 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
808 print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
809 }
810
811 void os::print_register_info(outputStream *st, void *context) {
812 if (context == NULL) return;
813
814 ucontext_t *uc = (ucontext_t*)context;
815
816 st->print_cr("Register to memory mapping:");
817 st->cr();
818
819 // this is horrendously verbose but the layout of the registers in the
820 // context does not match how we defined our abstract Register set, so
821 // we can't just iterate through the gregs area
822
823 // this is only for the "general purpose" registers
824
825 #ifdef AMD64
826 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
827 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
828 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
829 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
830 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
831 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
832 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
833 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
834 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
835 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
836 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
837 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
838 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
839 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
840 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
841 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
842 #else
843 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
844 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
845 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
846 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
847 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
848 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
849 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
850 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
851 #endif // AMD64
852
853 st->cr();
854 }
855
856 void os::setup_fpu() {
857 #ifndef AMD64
858 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
859 __asm__ volatile ( "fldcw (%0)" :
860 : "r" (fpu_cntrl) : "memory");
861 #endif // !AMD64
862 }
863
864 #ifndef PRODUCT
865 void os::verify_stack_alignment() {
866 #ifdef AMD64
867 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
868 #endif
869 }
870 #endif