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