1 /*
2 * Copyright (c) 1999, 2011, 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 "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/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/timer.hpp"
52 #include "thread_linux.inline.hpp"
53 #include "utilities/events.hpp"
54 #include "utilities/vmError.hpp"
55 #ifdef COMPILER1
56 #include "c1/c1_Runtime1.hpp"
57 #endif
58 #ifdef COMPILER2
59 #include "opto/runtime.hpp"
60 #endif
61
62 // put OS-includes here
63 # include <sys/types.h>
64 # include <sys/mman.h>
65 # include <pthread.h>
66 # include <signal.h>
67 # include <errno.h>
68 # include <dlfcn.h>
69 # include <stdlib.h>
70 # include <stdio.h>
71 # include <unistd.h>
72 # include <sys/resource.h>
73 # include <pthread.h>
74 # include <sys/stat.h>
75 # include <sys/time.h>
76 # include <sys/utsname.h>
77 # include <sys/socket.h>
78 # include <sys/wait.h>
79 # include <pwd.h>
80 # include <poll.h>
81 # include <ucontext.h>
82 # include <fpu_control.h>
83
84 #ifdef AMD64
85 #define REG_SP REG_RSP
86 #define REG_PC REG_RIP
87 #define REG_FP REG_RBP
88 #define SPELL_REG_SP "rsp"
89 #define SPELL_REG_FP "rbp"
90 #else
91 #define REG_SP REG_UESP
92 #define REG_PC REG_EIP
93 #define REG_FP REG_EBP
94 #define SPELL_REG_SP "esp"
95 #define SPELL_REG_FP "ebp"
96 #endif // AMD64
97
98 address os::current_stack_pointer() {
99 #ifdef SPARC_WORKS
100 register void *esp;
101 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
102 return (address) ((char*)esp + sizeof(long)*2);
103 #else
104 register void *esp __asm__ (SPELL_REG_SP);
105 return (address) esp;
106 #endif
107 }
108
109 char* os::non_memory_address_word() {
110 // Must never look like an address returned by reserve_memory,
111 // even in its subfields (as defined by the CPU immediate fields,
112 // if the CPU splits constants across multiple instructions).
113
114 return (char*) -1;
115 }
116
117 void os::initialize_thread() {
118 // Nothing to do.
119 }
120
121 address os::Linux::ucontext_get_pc(ucontext_t * uc) {
122 return (address)uc->uc_mcontext.gregs[REG_PC];
123 }
124
125 intptr_t* os::Linux::ucontext_get_sp(ucontext_t * uc) {
126 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
127 }
128
129 intptr_t* os::Linux::ucontext_get_fp(ucontext_t * uc) {
130 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
131 }
132
133 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
134 // is currently interrupted by SIGPROF.
135 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
136 // frames. Currently we don't do that on Linux, so it's the same as
137 // os::fetch_frame_from_context().
138 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
139 ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
140
141 assert(thread != NULL, "just checking");
142 assert(ret_sp != NULL, "just checking");
143 assert(ret_fp != NULL, "just checking");
144
145 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
146 }
147
148 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
149 intptr_t** ret_sp, intptr_t** ret_fp) {
150
151 ExtendedPC epc;
152 ucontext_t* uc = (ucontext_t*)ucVoid;
153
154 if (uc != NULL) {
155 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
156 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
157 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
158 } else {
159 // construct empty ExtendedPC for return value checking
160 epc = ExtendedPC(NULL);
161 if (ret_sp) *ret_sp = (intptr_t *)NULL;
162 if (ret_fp) *ret_fp = (intptr_t *)NULL;
163 }
164
165 return epc;
166 }
167
168 frame os::fetch_frame_from_context(void* ucVoid) {
169 intptr_t* sp;
170 intptr_t* fp;
171 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
172 return frame(sp, fp, epc.pc());
173 }
174
175 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
176 // turned off by -fomit-frame-pointer,
177 frame os::get_sender_for_C_frame(frame* fr) {
178 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
179 }
180
181 intptr_t* _get_previous_fp() {
182 #ifdef SPARC_WORKS
183 register intptr_t **ebp;
184 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
185 #else
186 register intptr_t **ebp __asm__ (SPELL_REG_FP);
187 #endif
188 return (intptr_t*) *ebp; // we want what it points to.
189 }
190
191
192 frame os::current_frame() {
193 intptr_t* fp = _get_previous_fp();
194 frame myframe((intptr_t*)os::current_stack_pointer(),
195 (intptr_t*)fp,
196 CAST_FROM_FN_PTR(address, os::current_frame));
197 if (os::is_first_C_frame(&myframe)) {
198 // stack is not walkable
199 return frame(NULL, NULL, NULL);
200 } else {
201 return os::get_sender_for_C_frame(&myframe);
202 }
203 }
204
205 // Utility functions
206
207 // From IA32 System Programming Guide
208 enum {
209 trap_page_fault = 0xE
210 };
211
212 extern "C" void Fetch32PFI () ;
213 extern "C" void Fetch32Resume () ;
214 #ifdef AMD64
215 extern "C" void FetchNPFI () ;
216 extern "C" void FetchNResume () ;
217 #endif // AMD64
218
219 extern "C" JNIEXPORT int
220 JVM_handle_linux_signal(int sig,
221 siginfo_t* info,
222 void* ucVoid,
223 int abort_if_unrecognized) {
224 ucontext_t* uc = (ucontext_t*) ucVoid;
225
226 Thread* t = ThreadLocalStorage::get_thread_slow();
227
228 SignalHandlerMark shm(t);
229
230 // Note: it's not uncommon that JNI code uses signal/sigset to install
231 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
232 // or have a SIGILL handler when detecting CPU type). When that happens,
233 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
234 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
235 // that do not require siginfo/ucontext first.
236
237 if (sig == SIGPIPE || sig == SIGXFSZ) {
238 // allow chained handler to go first
239 if (os::Linux::chained_handler(sig, info, ucVoid)) {
240 return true;
241 } else {
242 if (PrintMiscellaneous && (WizardMode || Verbose)) {
243 char buf[64];
244 warning("Ignoring %s - see bugs 4229104 or 646499219",
245 os::exception_name(sig, buf, sizeof(buf)));
246 }
247 return true;
248 }
249 }
250
251 JavaThread* thread = NULL;
252 VMThread* vmthread = NULL;
253 if (os::Linux::signal_handlers_are_installed) {
254 if (t != NULL ){
255 if(t->is_Java_thread()) {
256 thread = (JavaThread*)t;
257 }
258 else if(t->is_VM_thread()){
259 vmthread = (VMThread *)t;
260 }
261 }
262 }
263 /*
264 NOTE: does not seem to work on linux.
265 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
266 // can't decode this kind of signal
267 info = NULL;
268 } else {
269 assert(sig == info->si_signo, "bad siginfo");
270 }
271 */
272 // decide if this trap can be handled by a stub
273 address stub = NULL;
274
275 address pc = NULL;
276
277 //%note os_trap_1
278 if (info != NULL && uc != NULL && thread != NULL) {
279 pc = (address) os::Linux::ucontext_get_pc(uc);
280
281 if (pc == (address) Fetch32PFI) {
282 uc->uc_mcontext.gregs[REG_PC] = intptr_t(Fetch32Resume) ;
283 return 1 ;
284 }
285 #ifdef AMD64
286 if (pc == (address) FetchNPFI) {
287 uc->uc_mcontext.gregs[REG_PC] = intptr_t (FetchNResume) ;
288 return 1 ;
289 }
290 #endif // AMD64
291
292 // Handle ALL stack overflow variations here
293 if (sig == SIGSEGV) {
294 address addr = (address) info->si_addr;
295
296 // check if fault address is within thread stack
297 if (addr < thread->stack_base() &&
298 addr >= thread->stack_base() - thread->stack_size()) {
299 // stack overflow
300 if (thread->in_stack_yellow_zone(addr)) {
301 thread->disable_stack_yellow_zone();
302 if (thread->thread_state() == _thread_in_Java) {
303 // Throw a stack overflow exception. Guard pages will be reenabled
304 // while unwinding the stack.
305 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
306 } else {
307 // Thread was in the vm or native code. Return and try to finish.
308 return 1;
309 }
310 } else if (thread->in_stack_red_zone(addr)) {
311 // Fatal red zone violation. Disable the guard pages and fall through
312 // to handle_unexpected_exception way down below.
313 thread->disable_stack_red_zone();
314 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
315 } else {
316 // Accessing stack address below sp may cause SEGV if current
317 // thread has MAP_GROWSDOWN stack. This should only happen when
318 // current thread was created by user code with MAP_GROWSDOWN flag
319 // and then attached to VM. See notes in os_linux.cpp.
320 if (thread->osthread()->expanding_stack() == 0) {
321 thread->osthread()->set_expanding_stack();
322 if (os::Linux::manually_expand_stack(thread, addr)) {
323 thread->osthread()->clear_expanding_stack();
324 return 1;
325 }
326 thread->osthread()->clear_expanding_stack();
327 } else {
328 fatal("recursive segv. expanding stack.");
329 }
330 }
331 }
332 }
333
334 if (thread->thread_state() == _thread_in_Java) {
335 // Java thread running in Java code => find exception handler if any
336 // a fault inside compiled code, the interpreter, or a stub
337
338 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
339 stub = SharedRuntime::get_poll_stub(pc);
340 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
341 // BugId 4454115: A read from a MappedByteBuffer can fault
342 // here if the underlying file has been truncated.
343 // Do not crash the VM in such a case.
344 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
345 nmethod* nm = cb->is_nmethod() ? (nmethod*)cb : NULL;
346 if (nm != NULL && nm->has_unsafe_access()) {
347 stub = StubRoutines::handler_for_unsafe_access();
348 }
349 }
350 else
351
352 #ifdef AMD64
353 if (sig == SIGFPE &&
354 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
355 stub =
356 SharedRuntime::
357 continuation_for_implicit_exception(thread,
358 pc,
359 SharedRuntime::
360 IMPLICIT_DIVIDE_BY_ZERO);
361 #else
362 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
363 // HACK: si_code does not work on linux 2.2.12-20!!!
364 int op = pc[0];
365 if (op == 0xDB) {
366 // FIST
367 // TODO: The encoding of D2I in i486.ad can cause an exception
368 // prior to the fist instruction if there was an invalid operation
369 // pending. We want to dismiss that exception. From the win_32
370 // side it also seems that if it really was the fist causing
371 // the exception that we do the d2i by hand with different
372 // rounding. Seems kind of weird.
373 // NOTE: that we take the exception at the NEXT floating point instruction.
374 assert(pc[0] == 0xDB, "not a FIST opcode");
375 assert(pc[1] == 0x14, "not a FIST opcode");
376 assert(pc[2] == 0x24, "not a FIST opcode");
377 return true;
378 } else if (op == 0xF7) {
379 // IDIV
380 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
381 } else {
382 // TODO: handle more cases if we are using other x86 instructions
383 // that can generate SIGFPE signal on linux.
384 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
385 fatal("please update this code.");
386 }
387 #endif // AMD64
388 } else if (sig == SIGSEGV &&
389 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
390 // Determination of interpreter/vtable stub/compiled code null exception
391 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
392 }
393 } else if (thread->thread_state() == _thread_in_vm &&
394 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
395 thread->doing_unsafe_access()) {
396 stub = StubRoutines::handler_for_unsafe_access();
397 }
398
399 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
400 // and the heap gets shrunk before the field access.
401 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
402 address addr = JNI_FastGetField::find_slowcase_pc(pc);
403 if (addr != (address)-1) {
404 stub = addr;
405 }
406 }
407
408 // Check to see if we caught the safepoint code in the
409 // process of write protecting the memory serialization page.
410 // It write enables the page immediately after protecting it
411 // so we can just return to retry the write.
412 if ((sig == SIGSEGV) &&
413 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
414 // Block current thread until the memory serialize page permission restored.
415 os::block_on_serialize_page_trap();
416 return true;
417 }
418 }
419
420 #ifndef AMD64
421 // Execution protection violation
422 //
423 // This should be kept as the last step in the triage. We don't
424 // have a dedicated trap number for a no-execute fault, so be
425 // conservative and allow other handlers the first shot.
426 //
427 // Note: We don't test that info->si_code == SEGV_ACCERR here.
428 // this si_code is so generic that it is almost meaningless; and
429 // the si_code for this condition may change in the future.
430 // Furthermore, a false-positive should be harmless.
431 if (UnguardOnExecutionViolation > 0 &&
432 (sig == SIGSEGV || sig == SIGBUS) &&
433 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
434 int page_size = os::vm_page_size();
435 address addr = (address) info->si_addr;
436 address pc = os::Linux::ucontext_get_pc(uc);
437 // Make sure the pc and the faulting address are sane.
438 //
439 // If an instruction spans a page boundary, and the page containing
440 // the beginning of the instruction is executable but the following
441 // page is not, the pc and the faulting address might be slightly
442 // different - we still want to unguard the 2nd page in this case.
443 //
444 // 15 bytes seems to be a (very) safe value for max instruction size.
445 bool pc_is_near_addr =
446 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
447 bool instr_spans_page_boundary =
448 (align_size_down((intptr_t) pc ^ (intptr_t) addr,
449 (intptr_t) page_size) > 0);
450
451 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
452 static volatile address last_addr =
453 (address) os::non_memory_address_word();
454
455 // In conservative mode, don't unguard unless the address is in the VM
456 if (addr != last_addr &&
457 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
458
459 // Set memory to RWX and retry
460 address page_start =
461 (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
462 bool res = os::protect_memory((char*) page_start, page_size,
463 os::MEM_PROT_RWX);
464
465 if (PrintMiscellaneous && Verbose) {
466 char buf[256];
467 jio_snprintf(buf, sizeof(buf), "Execution protection violation "
468 "at " INTPTR_FORMAT
469 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,
470 page_start, (res ? "success" : "failed"), errno);
471 tty->print_raw_cr(buf);
472 }
473 stub = pc;
474
475 // Set last_addr so if we fault again at the same address, we don't end
476 // up in an endless loop.
477 //
478 // There are two potential complications here. Two threads trapping at
479 // the same address at the same time could cause one of the threads to
480 // think it already unguarded, and abort the VM. Likely very rare.
481 //
482 // The other race involves two threads alternately trapping at
483 // different addresses and failing to unguard the page, resulting in
484 // an endless loop. This condition is probably even more unlikely than
485 // the first.
486 //
487 // Although both cases could be avoided by using locks or thread local
488 // last_addr, these solutions are unnecessary complication: this
489 // handler is a best-effort safety net, not a complete solution. It is
490 // disabled by default and should only be used as a workaround in case
491 // we missed any no-execute-unsafe VM code.
492
493 last_addr = addr;
494 }
495 }
496 }
497 #endif // !AMD64
498
499 if (stub != NULL) {
500 // save all thread context in case we need to restore it
501 if (thread != NULL) thread->set_saved_exception_pc(pc);
502
503 uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub;
504 return true;
505 }
506
507 // signal-chaining
508 if (os::Linux::chained_handler(sig, info, ucVoid)) {
509 return true;
510 }
511
512 if (!abort_if_unrecognized) {
513 // caller wants another chance, so give it to him
514 return false;
515 }
516
517 if (pc == NULL && uc != NULL) {
518 pc = os::Linux::ucontext_get_pc(uc);
519 }
520
521 // unmask current signal
522 sigset_t newset;
523 sigemptyset(&newset);
524 sigaddset(&newset, sig);
525 sigprocmask(SIG_UNBLOCK, &newset, NULL);
526
527 VMError err(t, sig, pc, info, ucVoid);
528 err.report_and_die();
529
530 ShouldNotReachHere();
531 }
532
533 void os::Linux::init_thread_fpu_state(void) {
534 #ifndef AMD64
535 // set fpu to 53 bit precision
536 set_fpu_control_word(0x27f);
537 #endif // !AMD64
538 }
539
540 int os::Linux::get_fpu_control_word(void) {
541 #ifdef AMD64
542 return 0;
543 #else
544 int fpu_control;
545 _FPU_GETCW(fpu_control);
546 return fpu_control & 0xffff;
547 #endif // AMD64
548 }
549
550 void os::Linux::set_fpu_control_word(int fpu_control) {
551 #ifndef AMD64
552 _FPU_SETCW(fpu_control);
553 #endif // !AMD64
554 }
555
556 // Check that the linux kernel version is 2.4 or higher since earlier
557 // versions do not support SSE without patches.
558 bool os::supports_sse() {
559 #ifdef AMD64
560 return true;
561 #else
562 struct utsname uts;
563 if( uname(&uts) != 0 ) return false; // uname fails?
564 char *minor_string;
565 int major = strtol(uts.release,&minor_string,10);
566 int minor = strtol(minor_string+1,NULL,10);
567 bool result = (major > 2 || (major==2 && minor >= 4));
568 #ifndef PRODUCT
569 if (PrintMiscellaneous && Verbose) {
570 tty->print("OS version is %d.%d, which %s support SSE/SSE2\n",
571 major,minor, result ? "DOES" : "does NOT");
572 }
573 #endif
574 return result;
575 #endif // AMD64
576 }
577
578 bool os::is_allocatable(size_t bytes) {
579 #ifdef AMD64
580 // unused on amd64?
581 return true;
582 #else
583
584 if (bytes < 2 * G) {
585 return true;
586 }
587
588 char* addr = reserve_memory(bytes, NULL);
589
590 if (addr != NULL) {
591 release_memory(addr, bytes);
592 }
593
594 return addr != NULL;
595 #endif // AMD64
596 }
597
598 ////////////////////////////////////////////////////////////////////////////////
599 // thread stack
600
601 #ifdef AMD64
602 size_t os::Linux::min_stack_allowed = 64 * K;
603
604 // amd64: pthread on amd64 is always in floating stack mode
605 bool os::Linux::supports_variable_stack_size() { return true; }
606 #else
607 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K;
608
609 #ifdef __GNUC__
610 #define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})
611 #endif
612
613 // Test if pthread library can support variable thread stack size. LinuxThreads
614 // in fixed stack mode allocates 2M fixed slot for each thread. LinuxThreads
615 // in floating stack mode and NPTL support variable stack size.
616 bool os::Linux::supports_variable_stack_size() {
617 if (os::Linux::is_NPTL()) {
618 // NPTL, yes
619 return true;
620
621 } else {
622 // Note: We can't control default stack size when creating a thread.
623 // If we use non-default stack size (pthread_attr_setstacksize), both
624 // floating stack and non-floating stack LinuxThreads will return the
625 // same value. This makes it impossible to implement this function by
626 // detecting thread stack size directly.
627 //
628 // An alternative approach is to check %gs. Fixed-stack LinuxThreads
629 // do not use %gs, so its value is 0. Floating-stack LinuxThreads use
630 // %gs (either as LDT selector or GDT selector, depending on kernel)
631 // to access thread specific data.
632 //
633 // Note that %gs is a reserved glibc register since early 2001, so
634 // applications are not allowed to change its value (Ulrich Drepper from
635 // Redhat confirmed that all known offenders have been modified to use
636 // either %fs or TSD). In the worst case scenario, when VM is embedded in
637 // a native application that plays with %gs, we might see non-zero %gs
638 // even LinuxThreads is running in fixed stack mode. As the result, we'll
639 // return true and skip _thread_safety_check(), so we may not be able to
640 // detect stack-heap collisions. But otherwise it's harmless.
641 //
642 #ifdef __GNUC__
643 return (GET_GS() != 0);
644 #else
645 return false;
646 #endif
647 }
648 }
649 #endif // AMD64
650
651 // return default stack size for thr_type
652 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
653 // default stack size (compiler thread needs larger stack)
654 #ifdef AMD64
655 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
656 #else
657 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
658 #endif // AMD64
659 return s;
660 }
661
662 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
663 // Creating guard page is very expensive. Java thread has HotSpot
664 // guard page, only enable glibc guard page for non-Java threads.
665 return (thr_type == java_thread ? 0 : page_size());
666 }
667
668 // Java thread:
669 //
670 // Low memory addresses
671 // +------------------------+
672 // | |\ JavaThread created by VM does not have glibc
673 // | glibc guard page | - guard, attached Java thread usually has
674 // | |/ 1 page glibc guard.
675 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
676 // | |\
677 // | HotSpot Guard Pages | - red and yellow pages
678 // | |/
679 // +------------------------+ JavaThread::stack_yellow_zone_base()
680 // | |\
681 // | Normal Stack | -
682 // | |/
683 // P2 +------------------------+ Thread::stack_base()
684 //
685 // Non-Java thread:
686 //
687 // Low memory addresses
688 // +------------------------+
689 // | |\
690 // | glibc guard page | - usually 1 page
691 // | |/
692 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
693 // | |\
694 // | Normal Stack | -
695 // | |/
696 // P2 +------------------------+ Thread::stack_base()
697 //
698 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
699 // pthread_attr_getstack()
700
701 static void current_stack_region(address * bottom, size_t * size) {
702 if (os::Linux::is_initial_thread()) {
703 // initial thread needs special handling because pthread_getattr_np()
704 // may return bogus value.
705 *bottom = os::Linux::initial_thread_stack_bottom();
706 *size = os::Linux::initial_thread_stack_size();
707 } else {
708 pthread_attr_t attr;
709
710 int rslt = pthread_getattr_np(pthread_self(), &attr);
711
712 // JVM needs to know exact stack location, abort if it fails
713 if (rslt != 0) {
714 if (rslt == ENOMEM) {
715 vm_exit_out_of_memory(0, "pthread_getattr_np");
716 } else {
717 fatal(err_msg("pthread_getattr_np failed with errno = %d", rslt));
718 }
719 }
720
721 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
722 fatal("Can not locate current stack attributes!");
723 }
724
725 pthread_attr_destroy(&attr);
726
727 }
728 assert(os::current_stack_pointer() >= *bottom &&
729 os::current_stack_pointer() < *bottom + *size, "just checking");
730 }
731
732 address os::current_stack_base() {
733 address bottom;
734 size_t size;
735 current_stack_region(&bottom, &size);
736 return (bottom + size);
737 }
738
739 size_t os::current_stack_size() {
740 // stack size includes normal stack and HotSpot guard pages
741 address bottom;
742 size_t size;
743 current_stack_region(&bottom, &size);
744 return size;
745 }
746
747 /////////////////////////////////////////////////////////////////////////////
748 // helper functions for fatal error handler
749
750 void os::print_context(outputStream *st, void *context) {
751 if (context == NULL) return;
752
753 ucontext_t *uc = (ucontext_t*)context;
754 st->print_cr("Registers:");
755 #ifdef AMD64
756 st->print( "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
757 st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
758 st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
759 st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
760 st->cr();
761 st->print( "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
762 st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
763 st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
764 st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
765 st->cr();
766 st->print( "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
767 st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
768 st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
769 st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
770 st->cr();
771 st->print( "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
772 st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
773 st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
774 st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
775 st->cr();
776 st->print( "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
777 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
778 st->print(", CSGSFS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_CSGSFS]);
779 st->print(", ERR=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ERR]);
780 st->cr();
781 st->print(" TRAPNO=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_TRAPNO]);
782 #else
783 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
784 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
785 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
786 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
787 st->cr();
788 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
789 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
790 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
791 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
792 st->cr();
793 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
794 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
795 st->print(", CR2=" INTPTR_FORMAT, uc->uc_mcontext.cr2);
796 #endif // AMD64
797 st->cr();
798 st->cr();
799
800 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
801 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
802 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
803 st->cr();
804
805 // Note: it may be unsafe to inspect memory near pc. For example, pc may
806 // point to garbage if entry point in an nmethod is corrupted. Leave
807 // this at the end, and hope for the best.
808 address pc = os::Linux::ucontext_get_pc(uc);
809 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
810 print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
811 }
812
813 void os::print_register_info(outputStream *st, void *context) {
814 if (context == NULL) return;
815
816 ucontext_t *uc = (ucontext_t*)context;
817
818 st->print_cr("Register to memory mapping:");
819 st->cr();
820
821 // this is horrendously verbose but the layout of the registers in the
822 // context does not match how we defined our abstract Register set, so
823 // we can't just iterate through the gregs area
824
825 // this is only for the "general purpose" registers
826
827 #ifdef AMD64
828 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
829 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
830 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
831 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
832 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
833 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
834 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
835 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
836 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
837 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
838 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
839 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
840 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
841 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
842 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
843 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
844 #else
845 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
846 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
847 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
848 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
849 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
850 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
851 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
852 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
853 #endif // AMD64
854
855 st->cr();
856 }
857
858 void os::setup_fpu() {
859 #ifndef AMD64
860 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
861 __asm__ volatile ( "fldcw (%0)" :
862 : "r" (fpu_cntrl) : "memory");
863 #endif // !AMD64
864 }