1 /*
2 * Copyright (c) 1999, 2010, 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 #include "precompiled.hpp"
26 #include "assembler_x86.inline.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 "nativeInst_x86.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/hpi.hpp"
45 #include "runtime/interfaceSupport.hpp"
46 #include "runtime/java.hpp"
47 #include "runtime/javaCalls.hpp"
48 #include "runtime/mutexLocker.hpp"
49 #include "runtime/osThread.hpp"
50 #include "runtime/sharedRuntime.hpp"
51 #include "runtime/stubRoutines.hpp"
52 #include "runtime/timer.hpp"
53 #include "thread_linux.inline.hpp"
54 #include "utilities/events.hpp"
55 #include "utilities/vmError.hpp"
56 #ifdef COMPILER1
57 #include "c1/c1_Runtime1.hpp"
58 #endif
59 #ifdef COMPILER2
60 #include "opto/runtime.hpp"
61 #endif
62
63 // do not include precompiled header file
64 // put OS-includes here
65 # include <sys/types.h>
66 # include <sys/mman.h>
67 # include <pthread.h>
68 # include <signal.h>
69 # include <errno.h>
70 # include <dlfcn.h>
71 # include <stdlib.h>
72 # include <stdio.h>
73 # include <unistd.h>
74 # include <sys/resource.h>
75 # include <pthread.h>
76 # include <sys/stat.h>
77 # include <sys/time.h>
78 # include <sys/utsname.h>
79 # include <sys/socket.h>
80 # include <sys/wait.h>
81 # include <pwd.h>
82 # include <poll.h>
83 # include <ucontext.h>
84 # include <fpu_control.h>
85
86 #ifdef AMD64
87 #define REG_SP REG_RSP
88 #define REG_PC REG_RIP
89 #define REG_FP REG_RBP
90 #define SPELL_REG_SP "rsp"
91 #define SPELL_REG_FP "rbp"
92 #else
93 #define REG_SP REG_UESP
94 #define REG_PC REG_EIP
95 #define REG_FP REG_EBP
96 #define SPELL_REG_SP "esp"
97 #define SPELL_REG_FP "ebp"
98 #endif // AMD64
99
100 address os::current_stack_pointer() {
101 #ifdef SPARC_WORKS
102 register void *esp;
103 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
104 return (address) ((char*)esp + sizeof(long)*2);
105 #else
106 register void *esp __asm__ (SPELL_REG_SP);
107 return (address) esp;
108 #endif
109 }
110
111 char* os::non_memory_address_word() {
112 // Must never look like an address returned by reserve_memory,
113 // even in its subfields (as defined by the CPU immediate fields,
114 // if the CPU splits constants across multiple instructions).
115
116 return (char*) -1;
117 }
118
119 void os::initialize_thread() {
120 // Nothing to do.
121 }
122
123 address os::Linux::ucontext_get_pc(ucontext_t * uc) {
124 return (address)uc->uc_mcontext.gregs[REG_PC];
125 }
126
127 intptr_t* os::Linux::ucontext_get_sp(ucontext_t * uc) {
128 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
129 }
130
131 intptr_t* os::Linux::ucontext_get_fp(ucontext_t * uc) {
132 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
133 }
134
135 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
136 // is currently interrupted by SIGPROF.
137 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
138 // frames. Currently we don't do that on Linux, so it's the same as
139 // os::fetch_frame_from_context().
140 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
141 ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
142
143 assert(thread != NULL, "just checking");
144 assert(ret_sp != NULL, "just checking");
145 assert(ret_fp != NULL, "just checking");
146
147 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
148 }
149
150 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
151 intptr_t** ret_sp, intptr_t** ret_fp) {
152
153 ExtendedPC epc;
154 ucontext_t* uc = (ucontext_t*)ucVoid;
155
156 if (uc != NULL) {
157 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
158 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
159 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
160 } else {
161 // construct empty ExtendedPC for return value checking
162 epc = ExtendedPC(NULL);
163 if (ret_sp) *ret_sp = (intptr_t *)NULL;
164 if (ret_fp) *ret_fp = (intptr_t *)NULL;
165 }
166
167 return epc;
168 }
169
170 frame os::fetch_frame_from_context(void* ucVoid) {
171 intptr_t* sp;
172 intptr_t* fp;
173 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
174 return frame(sp, fp, epc.pc());
175 }
176
177 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
178 // turned off by -fomit-frame-pointer,
179 frame os::get_sender_for_C_frame(frame* fr) {
180 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
181 }
182
183 intptr_t* _get_previous_fp() {
184 #ifdef SPARC_WORKS
185 register intptr_t **ebp;
186 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
187 #else
188 register intptr_t **ebp __asm__ (SPELL_REG_FP);
189 #endif
190 return (intptr_t*) *ebp; // we want what it points to.
191 }
192
193
194 frame os::current_frame() {
195 intptr_t* fp = _get_previous_fp();
196 frame myframe((intptr_t*)os::current_stack_pointer(),
197 (intptr_t*)fp,
198 CAST_FROM_FN_PTR(address, os::current_frame));
199 if (os::is_first_C_frame(&myframe)) {
200 // stack is not walkable
201 return frame(NULL, NULL, NULL);
202 } else {
203 return os::get_sender_for_C_frame(&myframe);
204 }
205 }
206
207 // Utility functions
208
209 // From IA32 System Programming Guide
210 enum {
211 trap_page_fault = 0xE
212 };
213
214 extern "C" void Fetch32PFI () ;
215 extern "C" void Fetch32Resume () ;
216 #ifdef AMD64
217 extern "C" void FetchNPFI () ;
218 extern "C" void FetchNResume () ;
219 #endif // AMD64
220
221 extern "C" int
222 JVM_handle_linux_signal(int sig,
223 siginfo_t* info,
224 void* ucVoid,
225 int abort_if_unrecognized) {
226 ucontext_t* uc = (ucontext_t*) ucVoid;
227
228 Thread* t = ThreadLocalStorage::get_thread_slow();
229
230 SignalHandlerMark shm(t);
231
232 // Note: it's not uncommon that JNI code uses signal/sigset to install
233 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
234 // or have a SIGILL handler when detecting CPU type). When that happens,
235 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
236 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
237 // that do not require siginfo/ucontext first.
238
239 if (sig == SIGPIPE || sig == SIGXFSZ) {
240 // allow chained handler to go first
241 if (os::Linux::chained_handler(sig, info, ucVoid)) {
242 return true;
243 } else {
244 if (PrintMiscellaneous && (WizardMode || Verbose)) {
245 char buf[64];
246 warning("Ignoring %s - see bugs 4229104 or 646499219",
247 os::exception_name(sig, buf, sizeof(buf)));
248 }
249 return true;
250 }
251 }
252
253 JavaThread* thread = NULL;
254 VMThread* vmthread = NULL;
255 if (os::Linux::signal_handlers_are_installed) {
256 if (t != NULL ){
257 if(t->is_Java_thread()) {
258 thread = (JavaThread*)t;
259 }
260 else if(t->is_VM_thread()){
261 vmthread = (VMThread *)t;
262 }
263 }
264 }
265 /*
266 NOTE: does not seem to work on linux.
267 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
268 // can't decode this kind of signal
269 info = NULL;
270 } else {
271 assert(sig == info->si_signo, "bad siginfo");
272 }
273 */
274 // decide if this trap can be handled by a stub
275 address stub = NULL;
276
277 address pc = NULL;
278
279 //%note os_trap_1
280 if (info != NULL && uc != NULL && thread != NULL) {
281 pc = (address) os::Linux::ucontext_get_pc(uc);
282
283 if (pc == (address) Fetch32PFI) {
284 uc->uc_mcontext.gregs[REG_PC] = intptr_t(Fetch32Resume) ;
285 return 1 ;
286 }
287 #ifdef AMD64
288 if (pc == (address) FetchNPFI) {
289 uc->uc_mcontext.gregs[REG_PC] = intptr_t (FetchNResume) ;
290 return 1 ;
291 }
292 #endif // AMD64
293
294 // Handle ALL stack overflow variations here
295 if (sig == SIGSEGV) {
296 address addr = (address) info->si_addr;
297
298 // check if fault address is within thread stack
299 if (addr < thread->stack_base() &&
300 addr >= thread->stack_base() - thread->stack_size()) {
301 // stack overflow
302 if (thread->in_stack_yellow_zone(addr)) {
303 thread->disable_stack_yellow_zone();
304 if (thread->thread_state() == _thread_in_Java) {
305 // Throw a stack overflow exception. Guard pages will be reenabled
306 // while unwinding the stack.
307 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
308 } else {
309 // Thread was in the vm or native code. Return and try to finish.
310 return 1;
311 }
312 } else if (thread->in_stack_red_zone(addr)) {
313 // Fatal red zone violation. Disable the guard pages and fall through
314 // to handle_unexpected_exception way down below.
315 thread->disable_stack_red_zone();
316 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
317 } else {
318 // Accessing stack address below sp may cause SEGV if current
319 // thread has MAP_GROWSDOWN stack. This should only happen when
320 // current thread was created by user code with MAP_GROWSDOWN flag
321 // and then attached to VM. See notes in os_linux.cpp.
322 if (thread->osthread()->expanding_stack() == 0) {
323 thread->osthread()->set_expanding_stack();
324 if (os::Linux::manually_expand_stack(thread, addr)) {
325 thread->osthread()->clear_expanding_stack();
326 return 1;
327 }
328 thread->osthread()->clear_expanding_stack();
329 } else {
330 fatal("recursive segv. expanding stack.");
331 }
332 }
333 }
334 }
335
336 if (thread->thread_state() == _thread_in_Java) {
337 // Java thread running in Java code => find exception handler if any
338 // a fault inside compiled code, the interpreter, or a stub
339
340 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
341 stub = SharedRuntime::get_poll_stub(pc);
342 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
343 // BugId 4454115: A read from a MappedByteBuffer can fault
344 // here if the underlying file has been truncated.
345 // Do not crash the VM in such a case.
346 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
347 nmethod* nm = cb->is_nmethod() ? (nmethod*)cb : NULL;
348 if (nm != NULL && nm->has_unsafe_access()) {
349 stub = StubRoutines::handler_for_unsafe_access();
350 }
351 }
352 else
353
354 #ifdef AMD64
355 if (sig == SIGFPE &&
356 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
357 stub =
358 SharedRuntime::
359 continuation_for_implicit_exception(thread,
360 pc,
361 SharedRuntime::
362 IMPLICIT_DIVIDE_BY_ZERO);
363 #else
364 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
365 // HACK: si_code does not work on linux 2.2.12-20!!!
366 int op = pc[0];
367 if (op == 0xDB) {
368 // FIST
369 // TODO: The encoding of D2I in i486.ad can cause an exception
370 // prior to the fist instruction if there was an invalid operation
371 // pending. We want to dismiss that exception. From the win_32
372 // side it also seems that if it really was the fist causing
373 // the exception that we do the d2i by hand with different
374 // rounding. Seems kind of weird.
375 // NOTE: that we take the exception at the NEXT floating point instruction.
376 assert(pc[0] == 0xDB, "not a FIST opcode");
377 assert(pc[1] == 0x14, "not a FIST opcode");
378 assert(pc[2] == 0x24, "not a FIST opcode");
379 return true;
380 } else if (op == 0xF7) {
381 // IDIV
382 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
383 } else {
384 // TODO: handle more cases if we are using other x86 instructions
385 // that can generate SIGFPE signal on linux.
386 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
387 fatal("please update this code.");
388 }
389 #endif // AMD64
390 } else if (sig == SIGSEGV &&
391 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
392 // Determination of interpreter/vtable stub/compiled code null exception
393 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
394 }
395 } else if (thread->thread_state() == _thread_in_vm &&
396 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
397 thread->doing_unsafe_access()) {
398 stub = StubRoutines::handler_for_unsafe_access();
399 }
400
401 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
402 // and the heap gets shrunk before the field access.
403 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
404 address addr = JNI_FastGetField::find_slowcase_pc(pc);
405 if (addr != (address)-1) {
406 stub = addr;
407 }
408 }
409
410 // Check to see if we caught the safepoint code in the
411 // process of write protecting the memory serialization page.
412 // It write enables the page immediately after protecting it
413 // so we can just return to retry the write.
414 if ((sig == SIGSEGV) &&
415 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
416 // Block current thread until the memory serialize page permission restored.
417 os::block_on_serialize_page_trap();
418 return true;
419 }
420 }
421
422 #ifndef AMD64
423 // Execution protection violation
424 //
425 // This should be kept as the last step in the triage. We don't
426 // have a dedicated trap number for a no-execute fault, so be
427 // conservative and allow other handlers the first shot.
428 //
429 // Note: We don't test that info->si_code == SEGV_ACCERR here.
430 // this si_code is so generic that it is almost meaningless; and
431 // the si_code for this condition may change in the future.
432 // Furthermore, a false-positive should be harmless.
433 if (UnguardOnExecutionViolation > 0 &&
434 (sig == SIGSEGV || sig == SIGBUS) &&
435 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
436 int page_size = os::vm_page_size();
437 address addr = (address) info->si_addr;
438 address pc = os::Linux::ucontext_get_pc(uc);
439 // Make sure the pc and the faulting address are sane.
440 //
441 // If an instruction spans a page boundary, and the page containing
442 // the beginning of the instruction is executable but the following
443 // page is not, the pc and the faulting address might be slightly
444 // different - we still want to unguard the 2nd page in this case.
445 //
446 // 15 bytes seems to be a (very) safe value for max instruction size.
447 bool pc_is_near_addr =
448 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
449 bool instr_spans_page_boundary =
450 (align_size_down((intptr_t) pc ^ (intptr_t) addr,
451 (intptr_t) page_size) > 0);
452
453 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
454 static volatile address last_addr =
455 (address) os::non_memory_address_word();
456
457 // In conservative mode, don't unguard unless the address is in the VM
458 if (addr != last_addr &&
459 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
460
461 // Set memory to RWX and retry
462 address page_start =
463 (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
464 bool res = os::protect_memory((char*) page_start, page_size,
465 os::MEM_PROT_RWX);
466
467 if (PrintMiscellaneous && Verbose) {
468 char buf[256];
469 jio_snprintf(buf, sizeof(buf), "Execution protection violation "
470 "at " INTPTR_FORMAT
471 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,
472 page_start, (res ? "success" : "failed"), errno);
473 tty->print_raw_cr(buf);
474 }
475 stub = pc;
476
477 // Set last_addr so if we fault again at the same address, we don't end
478 // up in an endless loop.
479 //
480 // There are two potential complications here. Two threads trapping at
481 // the same address at the same time could cause one of the threads to
482 // think it already unguarded, and abort the VM. Likely very rare.
483 //
484 // The other race involves two threads alternately trapping at
485 // different addresses and failing to unguard the page, resulting in
486 // an endless loop. This condition is probably even more unlikely than
487 // the first.
488 //
489 // Although both cases could be avoided by using locks or thread local
490 // last_addr, these solutions are unnecessary complication: this
491 // handler is a best-effort safety net, not a complete solution. It is
492 // disabled by default and should only be used as a workaround in case
493 // we missed any no-execute-unsafe VM code.
494
495 last_addr = addr;
496 }
497 }
498 }
499 #endif // !AMD64
500
501 if (stub != NULL) {
502 // save all thread context in case we need to restore it
503 if (thread != NULL) thread->set_saved_exception_pc(pc);
504
505 uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub;
506 return true;
507 }
508
509 // signal-chaining
510 if (os::Linux::chained_handler(sig, info, ucVoid)) {
511 return true;
512 }
513
514 if (!abort_if_unrecognized) {
515 // caller wants another chance, so give it to him
516 return false;
517 }
518
519 if (pc == NULL && uc != NULL) {
520 pc = os::Linux::ucontext_get_pc(uc);
521 }
522
523 // unmask current signal
524 sigset_t newset;
525 sigemptyset(&newset);
526 sigaddset(&newset, sig);
527 sigprocmask(SIG_UNBLOCK, &newset, NULL);
528
529 VMError err(t, sig, pc, info, ucVoid);
530 err.report_and_die();
531
532 ShouldNotReachHere();
533 }
534
535 void os::Linux::init_thread_fpu_state(void) {
536 #ifndef AMD64
537 // set fpu to 53 bit precision
538 set_fpu_control_word(0x27f);
539 #endif // !AMD64
540 }
541
542 int os::Linux::get_fpu_control_word(void) {
543 #ifdef AMD64
544 return 0;
545 #else
546 int fpu_control;
547 _FPU_GETCW(fpu_control);
548 return fpu_control & 0xffff;
549 #endif // AMD64
550 }
551
552 void os::Linux::set_fpu_control_word(int fpu_control) {
553 #ifndef AMD64
554 _FPU_SETCW(fpu_control);
555 #endif // !AMD64
556 }
557
558 // Check that the linux kernel version is 2.4 or higher since earlier
559 // versions do not support SSE without patches.
560 bool os::supports_sse() {
561 #ifdef AMD64
562 return true;
563 #else
564 struct utsname uts;
565 if( uname(&uts) != 0 ) return false; // uname fails?
566 char *minor_string;
567 int major = strtol(uts.release,&minor_string,10);
568 int minor = strtol(minor_string+1,NULL,10);
569 bool result = (major > 2 || (major==2 && minor >= 4));
570 #ifndef PRODUCT
571 if (PrintMiscellaneous && Verbose) {
572 tty->print("OS version is %d.%d, which %s support SSE/SSE2\n",
573 major,minor, result ? "DOES" : "does NOT");
574 }
575 #endif
576 return result;
577 #endif // AMD64
578 }
579
580 bool os::is_allocatable(size_t bytes) {
581 #ifdef AMD64
582 // unused on amd64?
583 return true;
584 #else
585
586 if (bytes < 2 * G) {
587 return true;
588 }
589
590 char* addr = reserve_memory(bytes, NULL);
591
592 if (addr != NULL) {
593 release_memory(addr, bytes);
594 }
595
596 return addr != NULL;
597 #endif // AMD64
598 }
599
600 ////////////////////////////////////////////////////////////////////////////////
601 // thread stack
602
603 #ifdef AMD64
604 size_t os::Linux::min_stack_allowed = 64 * K;
605
606 // amd64: pthread on amd64 is always in floating stack mode
607 bool os::Linux::supports_variable_stack_size() { return true; }
608 #else
609 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K;
610
611 #ifdef __GNUC__
612 #define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})
613 #endif
614
615 // Test if pthread library can support variable thread stack size. LinuxThreads
616 // in fixed stack mode allocates 2M fixed slot for each thread. LinuxThreads
617 // in floating stack mode and NPTL support variable stack size.
618 bool os::Linux::supports_variable_stack_size() {
619 if (os::Linux::is_NPTL()) {
620 // NPTL, yes
621 return true;
622
623 } else {
624 // Note: We can't control default stack size when creating a thread.
625 // If we use non-default stack size (pthread_attr_setstacksize), both
626 // floating stack and non-floating stack LinuxThreads will return the
627 // same value. This makes it impossible to implement this function by
628 // detecting thread stack size directly.
629 //
630 // An alternative approach is to check %gs. Fixed-stack LinuxThreads
631 // do not use %gs, so its value is 0. Floating-stack LinuxThreads use
632 // %gs (either as LDT selector or GDT selector, depending on kernel)
633 // to access thread specific data.
634 //
635 // Note that %gs is a reserved glibc register since early 2001, so
636 // applications are not allowed to change its value (Ulrich Drepper from
637 // Redhat confirmed that all known offenders have been modified to use
638 // either %fs or TSD). In the worst case scenario, when VM is embedded in
639 // a native application that plays with %gs, we might see non-zero %gs
640 // even LinuxThreads is running in fixed stack mode. As the result, we'll
641 // return true and skip _thread_safety_check(), so we may not be able to
642 // detect stack-heap collisions. But otherwise it's harmless.
643 //
644 #ifdef __GNUC__
645 return (GET_GS() != 0);
646 #else
647 return false;
648 #endif
649 }
650 }
651 #endif // AMD64
652
653 // return default stack size for thr_type
654 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
655 // default stack size (compiler thread needs larger stack)
656 #ifdef AMD64
657 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
658 #else
659 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
660 #endif // AMD64
661 return s;
662 }
663
664 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
665 // Creating guard page is very expensive. Java thread has HotSpot
666 // guard page, only enable glibc guard page for non-Java threads.
667 return (thr_type == java_thread ? 0 : page_size());
668 }
669
670 // Java thread:
671 //
672 // Low memory addresses
673 // +------------------------+
674 // | |\ JavaThread created by VM does not have glibc
675 // | glibc guard page | - guard, attached Java thread usually has
676 // | |/ 1 page glibc guard.
677 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
678 // | |\
679 // | HotSpot Guard Pages | - red and yellow pages
680 // | |/
681 // +------------------------+ JavaThread::stack_yellow_zone_base()
682 // | |\
683 // | Normal Stack | -
684 // | |/
685 // P2 +------------------------+ Thread::stack_base()
686 //
687 // Non-Java thread:
688 //
689 // Low memory addresses
690 // +------------------------+
691 // | |\
692 // | glibc guard page | - usually 1 page
693 // | |/
694 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
695 // | |\
696 // | Normal Stack | -
697 // | |/
698 // P2 +------------------------+ Thread::stack_base()
699 //
700 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
701 // pthread_attr_getstack()
702
703 static void current_stack_region(address * bottom, size_t * size) {
704 if (os::Linux::is_initial_thread()) {
705 // initial thread needs special handling because pthread_getattr_np()
706 // may return bogus value.
707 *bottom = os::Linux::initial_thread_stack_bottom();
708 *size = os::Linux::initial_thread_stack_size();
709 } else {
710 pthread_attr_t attr;
711
712 int rslt = pthread_getattr_np(pthread_self(), &attr);
713
714 // JVM needs to know exact stack location, abort if it fails
715 if (rslt != 0) {
716 if (rslt == ENOMEM) {
717 vm_exit_out_of_memory(0, "pthread_getattr_np");
718 } else {
719 fatal(err_msg("pthread_getattr_np failed with errno = %d", rslt));
720 }
721 }
722
723 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
724 fatal("Can not locate current stack attributes!");
725 }
726
727 pthread_attr_destroy(&attr);
728
729 }
730 assert(os::current_stack_pointer() >= *bottom &&
731 os::current_stack_pointer() < *bottom + *size, "just checking");
732 }
733
734 address os::current_stack_base() {
735 address bottom;
736 size_t size;
737 current_stack_region(&bottom, &size);
738 return (bottom + size);
739 }
740
741 size_t os::current_stack_size() {
742 // stack size includes normal stack and HotSpot guard pages
743 address bottom;
744 size_t size;
745 current_stack_region(&bottom, &size);
746 return size;
747 }
748
749 /////////////////////////////////////////////////////////////////////////////
750 // helper functions for fatal error handler
751
752 void os::print_context(outputStream *st, void *context) {
753 if (context == NULL) return;
754
755 ucontext_t *uc = (ucontext_t*)context;
756 st->print_cr("Registers:");
757
758 // this is horrendously verbose but the layout of the registers in the
759 // context does not match how we defined our abstract Register set, so
760 // we can't just iterate through the gregs area
761
762 #ifdef AMD64
763 st->print( "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
764 st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
765 st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
766 st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
767 st->cr();
768 st->print( "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
769 st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
770 st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
771 st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
772 st->cr();
773 st->print( "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
774 st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
775 st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
776 st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
777 st->cr();
778 st->print( "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
779 st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
780 st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
781 st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
782 st->cr();
783 st->print( "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
784 st->print(", EFL=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
785 st->print(", CSGSFS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_CSGSFS]);
786 st->print(", ERR=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ERR]);
787 st->cr();
788 st->print(" TRAPNO=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_TRAPNO]);
789
790 st->cr();
791 st->cr();
792
793 st->print_cr("Register to memory mapping:");
794 st->cr();
795
796 // this is only for the "general purpose" registers
797
798 st->print_cr("RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
799 print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
800 st->cr();
801 st->print_cr("RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
802 print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
803 st->cr();
804 st->print_cr("RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
805 print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
806 st->cr();
807 st->print_cr("RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
808 print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
809 st->cr();
810 st->print_cr("RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
811 print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
812 st->cr();
813 st->print_cr("RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
814 print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
815 st->cr();
816 st->print_cr("RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
817 print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
818 st->cr();
819 st->print_cr("RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
820 print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
821 st->cr();
822 st->print_cr("R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
823 print_location(st, uc->uc_mcontext.gregs[REG_R8]);
824 st->cr();
825 st->print_cr("R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
826 print_location(st, uc->uc_mcontext.gregs[REG_R9]);
827 st->cr();
828 st->print_cr("R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
829 print_location(st, uc->uc_mcontext.gregs[REG_R10]);
830 st->cr();
831 st->print_cr("R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
832 print_location(st, uc->uc_mcontext.gregs[REG_R11]);
833 st->cr();
834 st->print_cr("R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
835 print_location(st, uc->uc_mcontext.gregs[REG_R12]);
836 st->cr();
837 st->print_cr("R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
838 print_location(st, uc->uc_mcontext.gregs[REG_R13]);
839 st->cr();
840 st->print_cr("R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
841 print_location(st, uc->uc_mcontext.gregs[REG_R14]);
842 st->cr();
843 st->print_cr("R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
844 print_location(st, uc->uc_mcontext.gregs[REG_R15]);
845
846 #else
847 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
848 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
849 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
850 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
851 st->cr();
852 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
853 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
854 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
855 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
856 st->cr();
857 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
858 st->print(", CR2=" INTPTR_FORMAT, uc->uc_mcontext.cr2);
859 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
860
861 st->cr();
862 st->cr();
863
864 st->print_cr("Register to memory mapping:");
865 st->cr();
866
867 // this is only for the "general purpose" registers
868
869 st->print_cr("EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
870 print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
871 st->cr();
872 st->print_cr("EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
873 print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
874 st->cr();
875 st->print_cr("ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
876 print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
877 st->cr();
878 st->print_cr("EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
879 print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
880 st->cr();
881 st->print_cr("ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESP]);
882 print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
883 st->cr();
884 st->print_cr("EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
885 print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
886 st->cr();
887 st->print_cr("ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
888 print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
889 st->cr();
890 st->print_cr("EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
891 print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
892
893 #endif // AMD64
894 st->cr();
895 st->cr();
896
897 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
898 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
899 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
900 st->cr();
901
902 // Note: it may be unsafe to inspect memory near pc. For example, pc may
903 // point to garbage if entry point in an nmethod is corrupted. Leave
904 // this at the end, and hope for the best.
905 address pc = os::Linux::ucontext_get_pc(uc);
906 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
907 print_hex_dump(st, pc - 16, pc + 16, sizeof(char));
908 }
909
910 void os::setup_fpu() {
911 #ifndef AMD64
912 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
913 __asm__ volatile ( "fldcw (%0)" :
914 : "r" (fpu_cntrl) : "memory");
915 #endif // !AMD64
916 }