1 /*
2 * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // no precompiled headers
26 #include "asm/macroAssembler.hpp"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/icBuffer.hpp"
31 #include "code/vtableStubs.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "jvm_linux.h"
34 #include "memory/allocation.inline.hpp"
35 #include "mutex_linux.inline.hpp"
36 #include "os_share_linux.hpp"
37 #include "prims/jniFastGetField.hpp"
38 #include "prims/jvm.h"
39 #include "prims/jvm_misc.hpp"
40 #include "runtime/arguments.hpp"
41 #include "runtime/extendedPC.hpp"
42 #include "runtime/frame.inline.hpp"
43 #include "runtime/interfaceSupport.hpp"
44 #include "runtime/java.hpp"
45 #include "runtime/javaCalls.hpp"
46 #include "runtime/mutexLocker.hpp"
47 #include "runtime/osThread.hpp"
48 #include "runtime/sharedRuntime.hpp"
49 #include "runtime/stubRoutines.hpp"
50 #include "runtime/thread.inline.hpp"
51 #include "runtime/timer.hpp"
52 #include "utilities/events.hpp"
53 #include "utilities/vmError.hpp"
54
55 // put OS-includes here
56 # include <sys/types.h>
57 # include <sys/mman.h>
58 # include <pthread.h>
59 # include <signal.h>
60 # include <errno.h>
61 # include <dlfcn.h>
62 # include <stdlib.h>
63 # include <stdio.h>
64 # include <unistd.h>
65 # include <sys/resource.h>
66 # include <pthread.h>
67 # include <sys/stat.h>
68 # include <sys/time.h>
69 # include <sys/utsname.h>
70 # include <sys/socket.h>
71 # include <sys/wait.h>
72 # include <pwd.h>
73 # include <poll.h>
74 # include <ucontext.h>
75 # include <fpu_control.h>
76
77 #ifdef AMD64
78 #define REG_SP REG_RSP
79 #define REG_PC REG_RIP
80 #define REG_FP REG_RBP
81 #define SPELL_REG_SP "rsp"
82 #define SPELL_REG_FP "rbp"
83 #else
84 #define REG_SP REG_UESP
85 #define REG_PC REG_EIP
86 #define REG_FP REG_EBP
87 #define SPELL_REG_SP "esp"
88 #define SPELL_REG_FP "ebp"
89 #endif // AMD64
90
91 address os::current_stack_pointer() {
92 #ifdef SPARC_WORKS
93 register void *esp;
94 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
95 return (address) ((char*)esp + sizeof(long)*2);
96 #elif defined(__clang__)
97 intptr_t* esp;
98 __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):);
99 return (address) esp;
100 #else
101 register void *esp __asm__ (SPELL_REG_SP);
102 return (address) esp;
103 #endif
104 }
105
106 char* os::non_memory_address_word() {
107 // Must never look like an address returned by reserve_memory,
108 // even in its subfields (as defined by the CPU immediate fields,
109 // if the CPU splits constants across multiple instructions).
110
111 return (char*) -1;
112 }
113
114 void os::initialize_thread(Thread* thr) {
115 // Nothing to do.
116 }
117
118 address os::Linux::ucontext_get_pc(ucontext_t * uc) {
119 return (address)uc->uc_mcontext.gregs[REG_PC];
120 }
121
122 intptr_t* os::Linux::ucontext_get_sp(ucontext_t * uc) {
123 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
124 }
125
126 intptr_t* os::Linux::ucontext_get_fp(ucontext_t * uc) {
127 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
128 }
129
130 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
131 // is currently interrupted by SIGPROF.
132 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
133 // frames. Currently we don't do that on Linux, so it's the same as
134 // os::fetch_frame_from_context().
135 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
136 ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
137
138 assert(thread != NULL, "just checking");
139 assert(ret_sp != NULL, "just checking");
140 assert(ret_fp != NULL, "just checking");
141
142 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
143 }
144
145 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
146 intptr_t** ret_sp, intptr_t** ret_fp) {
147
148 ExtendedPC epc;
149 ucontext_t* uc = (ucontext_t*)ucVoid;
150
151 if (uc != NULL) {
152 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
153 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
154 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
155 } else {
156 // construct empty ExtendedPC for return value checking
157 epc = ExtendedPC(NULL);
158 if (ret_sp) *ret_sp = (intptr_t *)NULL;
159 if (ret_fp) *ret_fp = (intptr_t *)NULL;
160 }
161
162 return epc;
163 }
164
165 frame os::fetch_frame_from_context(void* ucVoid) {
166 intptr_t* sp;
167 intptr_t* fp;
168 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
169 return frame(sp, fp, epc.pc());
170 }
171
172 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
173 // turned off by -fomit-frame-pointer,
174 frame os::get_sender_for_C_frame(frame* fr) {
175 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
176 }
177
178 intptr_t* _get_previous_fp() {
179 #ifdef SPARC_WORKS
180 register intptr_t **ebp;
181 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
182 #elif defined(__clang__)
183 intptr_t **ebp;
184 __asm__ __volatile__ ("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();
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" JNIEXPORT int
213 JVM_handle_linux_signal(int sig,
214 siginfo_t* info,
215 void* ucVoid,
216 int abort_if_unrecognized) {
217 ucontext_t* uc = (ucontext_t*) ucVoid;
218
219 Thread* t = ThreadLocalStorage::get_thread_slow();
220
221 SignalHandlerMark shm(t);
222
223 // Note: it's not uncommon that JNI code uses signal/sigset to install
224 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
225 // or have a SIGILL handler when detecting CPU type). When that happens,
226 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
227 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
228 // that do not require siginfo/ucontext first.
229
230 if (sig == SIGPIPE || sig == SIGXFSZ) {
231 // allow chained handler to go first
232 if (os::Linux::chained_handler(sig, info, ucVoid)) {
233 return true;
234 } else {
235 if (PrintMiscellaneous && (WizardMode || Verbose)) {
236 char buf[64];
237 warning("Ignoring %s - see bugs 4229104 or 646499219",
238 os::exception_name(sig, buf, sizeof(buf)));
239 }
240 return true;
241 }
242 }
243
244 JavaThread* thread = NULL;
245 VMThread* vmthread = NULL;
246 if (os::Linux::signal_handlers_are_installed) {
247 if (t != NULL ){
248 if(t->is_Java_thread()) {
249 thread = (JavaThread*)t;
250 }
251 else if(t->is_VM_thread()){
252 vmthread = (VMThread *)t;
253 }
254 }
255 }
256 /*
257 NOTE: does not seem to work on linux.
258 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
259 // can't decode this kind of signal
260 info = NULL;
261 } else {
262 assert(sig == info->si_signo, "bad siginfo");
263 }
264 */
265 // decide if this trap can be handled by a stub
266 address stub = NULL;
267
268 address pc = NULL;
269
270 //%note os_trap_1
271 if (info != NULL && uc != NULL && thread != NULL) {
272 pc = (address) os::Linux::ucontext_get_pc(uc);
273
274 if (StubRoutines::is_safefetch_fault(pc)) {
275 uc->uc_mcontext.gregs[REG_PC] = intptr_t(StubRoutines::continuation_for_safefetch_fault(pc));
276 return 1;
277 }
278
279 // Handle ALL stack overflow variations here
280 if (sig == SIGSEGV) {
281 address addr = (address) info->si_addr;
282
283 // check if fault address is within thread stack
284 if (addr < thread->stack_base() &&
285 addr >= thread->stack_base() - thread->stack_size()) {
286 // stack overflow
287 if (thread->in_stack_yellow_zone(addr)) {
288 thread->disable_stack_yellow_zone();
289 if (thread->thread_state() == _thread_in_Java) {
290 // Throw a stack overflow exception. Guard pages will be reenabled
291 // while unwinding the stack.
292 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
293 } else {
294 // Thread was in the vm or native code. Return and try to finish.
295 return 1;
296 }
297 } else if (thread->in_stack_red_zone(addr)) {
298 // Fatal red zone violation. Disable the guard pages and fall through
299 // to handle_unexpected_exception way down below.
300 thread->disable_stack_red_zone();
301 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
302
303 // This is a likely cause, but hard to verify. Let's just print
304 // it as a hint.
305 tty->print_raw_cr("Please check if any of your loaded .so files has "
306 "enabled executable stack (see man page execstack(8))");
307 } else {
308 // Accessing stack address below sp may cause SEGV if current
309 // thread has MAP_GROWSDOWN stack. This should only happen when
310 // current thread was created by user code with MAP_GROWSDOWN flag
311 // and then attached to VM. See notes in os_linux.cpp.
312 if (thread->osthread()->expanding_stack() == 0) {
313 thread->osthread()->set_expanding_stack();
314 if (os::Linux::manually_expand_stack(thread, addr)) {
315 thread->osthread()->clear_expanding_stack();
316 return 1;
317 }
318 thread->osthread()->clear_expanding_stack();
319 } else {
320 fatal("recursive segv. expanding stack.");
321 }
322 }
323 }
324 }
325
326 if (thread->thread_state() == _thread_in_Java) {
327 // Java thread running in Java code => find exception handler if any
328 // a fault inside compiled code, the interpreter, or a stub
329
330 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
331 stub = SharedRuntime::get_poll_stub(pc);
332 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
333 // BugId 4454115: A read from a MappedByteBuffer can fault
334 // here if the underlying file has been truncated.
335 // Do not crash the VM in such a case.
336 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
337 nmethod* nm = (cb != NULL && cb->is_nmethod()) ? (nmethod*)cb : NULL;
338 if (nm != NULL && nm->has_unsafe_access()) {
339 stub = StubRoutines::handler_for_unsafe_access();
340 }
341 }
342 else
343
344 #ifdef AMD64
345 if (sig == SIGFPE &&
346 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
347 stub =
348 SharedRuntime::
349 continuation_for_implicit_exception(thread,
350 pc,
351 SharedRuntime::
352 IMPLICIT_DIVIDE_BY_ZERO);
353 #else
354 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
355 // HACK: si_code does not work on linux 2.2.12-20!!!
356 int op = pc[0];
357 if (op == 0xDB) {
358 // FIST
359 // TODO: The encoding of D2I in i486.ad can cause an exception
360 // prior to the fist instruction if there was an invalid operation
361 // pending. We want to dismiss that exception. From the win_32
362 // side it also seems that if it really was the fist causing
363 // the exception that we do the d2i by hand with different
364 // rounding. Seems kind of weird.
365 // NOTE: that we take the exception at the NEXT floating point instruction.
366 assert(pc[0] == 0xDB, "not a FIST opcode");
367 assert(pc[1] == 0x14, "not a FIST opcode");
368 assert(pc[2] == 0x24, "not a FIST opcode");
369 return true;
370 } else if (op == 0xF7) {
371 // IDIV
372 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
373 } else {
374 // TODO: handle more cases if we are using other x86 instructions
375 // that can generate SIGFPE signal on linux.
376 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
377 fatal("please update this code.");
378 }
379 #endif // AMD64
380 } else if (sig == SIGSEGV &&
381 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
382 // Determination of interpreter/vtable stub/compiled code null exception
383 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
384 }
385 } else if (thread->thread_state() == _thread_in_vm &&
386 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
387 thread->doing_unsafe_access()) {
388 stub = StubRoutines::handler_for_unsafe_access();
389 }
390
391 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
392 // and the heap gets shrunk before the field access.
393 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
394 address addr = JNI_FastGetField::find_slowcase_pc(pc);
395 if (addr != (address)-1) {
396 stub = addr;
397 }
398 }
399
400 // Check to see if we caught the safepoint code in the
401 // process of write protecting the memory serialization page.
402 // It write enables the page immediately after protecting it
403 // so we can just return to retry the write.
404 if ((sig == SIGSEGV) &&
405 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
406 // Block current thread until the memory serialize page permission restored.
407 os::block_on_serialize_page_trap();
408 return true;
409 }
410 }
411
412 #ifndef AMD64
413 // Execution protection violation
414 //
415 // This should be kept as the last step in the triage. We don't
416 // have a dedicated trap number for a no-execute fault, so be
417 // conservative and allow other handlers the first shot.
418 //
419 // Note: We don't test that info->si_code == SEGV_ACCERR here.
420 // this si_code is so generic that it is almost meaningless; and
421 // the si_code for this condition may change in the future.
422 // Furthermore, a false-positive should be harmless.
423 if (UnguardOnExecutionViolation > 0 &&
424 (sig == SIGSEGV || sig == SIGBUS) &&
425 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
426 int page_size = os::vm_page_size();
427 address addr = (address) info->si_addr;
428 address pc = os::Linux::ucontext_get_pc(uc);
429 // Make sure the pc and the faulting address are sane.
430 //
431 // If an instruction spans a page boundary, and the page containing
432 // the beginning of the instruction is executable but the following
433 // page is not, the pc and the faulting address might be slightly
434 // different - we still want to unguard the 2nd page in this case.
435 //
436 // 15 bytes seems to be a (very) safe value for max instruction size.
437 bool pc_is_near_addr =
438 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
439 bool instr_spans_page_boundary =
440 (align_size_down((intptr_t) pc ^ (intptr_t) addr,
441 (intptr_t) page_size) > 0);
442
443 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
444 static volatile address last_addr =
445 (address) os::non_memory_address_word();
446
447 // In conservative mode, don't unguard unless the address is in the VM
448 if (addr != last_addr &&
449 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
450
451 // Set memory to RWX and retry
452 address page_start =
453 (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
454 bool res = os::protect_memory((char*) page_start, page_size,
455 os::MEM_PROT_RWX);
456
457 if (PrintMiscellaneous && Verbose) {
458 char buf[256];
459 jio_snprintf(buf, sizeof(buf), "Execution protection violation "
460 "at " INTPTR_FORMAT
461 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,
462 page_start, (res ? "success" : "failed"), errno);
463 tty->print_raw_cr(buf);
464 }
465 stub = pc;
466
467 // Set last_addr so if we fault again at the same address, we don't end
468 // up in an endless loop.
469 //
470 // There are two potential complications here. Two threads trapping at
471 // the same address at the same time could cause one of the threads to
472 // think it already unguarded, and abort the VM. Likely very rare.
473 //
474 // The other race involves two threads alternately trapping at
475 // different addresses and failing to unguard the page, resulting in
476 // an endless loop. This condition is probably even more unlikely than
477 // the first.
478 //
479 // Although both cases could be avoided by using locks or thread local
480 // last_addr, these solutions are unnecessary complication: this
481 // handler is a best-effort safety net, not a complete solution. It is
482 // disabled by default and should only be used as a workaround in case
483 // we missed any no-execute-unsafe VM code.
484
485 last_addr = addr;
486 }
487 }
488 }
489 #endif // !AMD64
490
491 if (stub != NULL) {
492 // save all thread context in case we need to restore it
493 if (thread != NULL) thread->set_saved_exception_pc(pc);
494
495 uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub;
496 return true;
497 }
498
499 // signal-chaining
500 if (os::Linux::chained_handler(sig, info, ucVoid)) {
501 return true;
502 }
503
504 if (!abort_if_unrecognized) {
505 // caller wants another chance, so give it to him
506 return false;
507 }
508
509 if (pc == NULL && uc != NULL) {
510 pc = os::Linux::ucontext_get_pc(uc);
511 }
512
513 // unmask current signal
514 sigset_t newset;
515 sigemptyset(&newset);
516 sigaddset(&newset, sig);
517 sigprocmask(SIG_UNBLOCK, &newset, NULL);
518
519 VMError err(t, sig, pc, info, ucVoid);
520 err.report_and_die();
521
522 ShouldNotReachHere();
523 }
524
525 void os::Linux::init_thread_fpu_state(void) {
526 #ifndef AMD64
527 // set fpu to 53 bit precision
528 set_fpu_control_word(0x27f);
529 #endif // !AMD64
530 }
531
532 int os::Linux::get_fpu_control_word(void) {
533 #ifdef AMD64
534 return 0;
535 #else
536 int fpu_control;
537 _FPU_GETCW(fpu_control);
538 return fpu_control & 0xffff;
539 #endif // AMD64
540 }
541
542 void os::Linux::set_fpu_control_word(int fpu_control) {
543 #ifndef AMD64
544 _FPU_SETCW(fpu_control);
545 #endif // !AMD64
546 }
547
548 // Check that the linux kernel version is 2.4 or higher since earlier
549 // versions do not support SSE without patches.
550 bool os::supports_sse() {
551 #ifdef AMD64
552 return true;
553 #else
554 struct utsname uts;
555 if( uname(&uts) != 0 ) return false; // uname fails?
556 char *minor_string;
557 int major = strtol(uts.release,&minor_string,10);
558 int minor = strtol(minor_string+1,NULL,10);
559 bool result = (major > 2 || (major==2 && minor >= 4));
560 #ifndef PRODUCT
561 if (PrintMiscellaneous && Verbose) {
562 tty->print("OS version is %d.%d, which %s support SSE/SSE2\n",
563 major,minor, result ? "DOES" : "does NOT");
564 }
565 #endif
566 return result;
567 #endif // AMD64
568 }
569
570 bool os::is_allocatable(size_t bytes) {
571 #ifdef AMD64
572 // unused on amd64?
573 return true;
574 #else
575
576 if (bytes < 2 * G) {
577 return true;
578 }
579
580 char* addr = reserve_memory(bytes, NULL);
581
582 if (addr != NULL) {
583 release_memory(addr, bytes);
584 }
585
586 return addr != NULL;
587 #endif // AMD64
588 }
589
590 ////////////////////////////////////////////////////////////////////////////////
591 // thread stack
592
593 #ifdef AMD64
594 size_t os::Linux::min_stack_allowed = 64 * K;
595
596 // amd64: pthread on amd64 is always in floating stack mode
597 bool os::Linux::supports_variable_stack_size() { return true; }
598 #else
599 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K;
600
601 #ifdef __GNUC__
602 #define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})
603 #endif
604
605 // Test if pthread library can support variable thread stack size. LinuxThreads
606 // in fixed stack mode allocates 2M fixed slot for each thread. LinuxThreads
607 // in floating stack mode and NPTL support variable stack size.
608 bool os::Linux::supports_variable_stack_size() {
609 if (os::Linux::is_NPTL()) {
610 // NPTL, yes
611 return true;
612
613 } else {
614 // Note: We can't control default stack size when creating a thread.
615 // If we use non-default stack size (pthread_attr_setstacksize), both
616 // floating stack and non-floating stack LinuxThreads will return the
617 // same value. This makes it impossible to implement this function by
618 // detecting thread stack size directly.
619 //
620 // An alternative approach is to check %gs. Fixed-stack LinuxThreads
621 // do not use %gs, so its value is 0. Floating-stack LinuxThreads use
622 // %gs (either as LDT selector or GDT selector, depending on kernel)
623 // to access thread specific data.
624 //
625 // Note that %gs is a reserved glibc register since early 2001, so
626 // applications are not allowed to change its value (Ulrich Drepper from
627 // Redhat confirmed that all known offenders have been modified to use
628 // either %fs or TSD). In the worst case scenario, when VM is embedded in
629 // a native application that plays with %gs, we might see non-zero %gs
630 // even LinuxThreads is running in fixed stack mode. As the result, we'll
631 // return true and skip _thread_safety_check(), so we may not be able to
632 // detect stack-heap collisions. But otherwise it's harmless.
633 //
634 #ifdef __GNUC__
635 return (GET_GS() != 0);
636 #else
637 return false;
638 #endif
639 }
640 }
641 #endif // AMD64
642
643 // return default stack size for thr_type
644 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
645 // default stack size (compiler thread needs larger stack)
646 #ifdef AMD64
647 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
648 #else
649 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
650 #endif // AMD64
651 return s;
652 }
653
654 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
655 // Creating guard page is very expensive. Java thread has HotSpot
656 // guard page, only enable glibc guard page for non-Java threads.
657 return (thr_type == java_thread ? 0 : page_size());
658 }
659
660 // Java thread:
661 //
662 // Low memory addresses
663 // +------------------------+
664 // | |\ JavaThread created by VM does not have glibc
665 // | glibc guard page | - guard, attached Java thread usually has
666 // | |/ 1 page glibc guard.
667 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
668 // | |\
669 // | HotSpot Guard Pages | - red and yellow pages
670 // | |/
671 // +------------------------+ JavaThread::stack_yellow_zone_base()
672 // | |\
673 // | Normal Stack | -
674 // | |/
675 // P2 +------------------------+ Thread::stack_base()
676 //
677 // Non-Java thread:
678 //
679 // Low memory addresses
680 // +------------------------+
681 // | |\
682 // | glibc guard page | - usually 1 page
683 // | |/
684 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
685 // | |\
686 // | Normal Stack | -
687 // | |/
688 // P2 +------------------------+ Thread::stack_base()
689 //
690 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
691 // pthread_attr_getstack()
692
693 static void current_stack_region(address * bottom, size_t * size) {
694 if (os::Linux::is_initial_thread()) {
695 // initial thread needs special handling because pthread_getattr_np()
696 // may return bogus value.
697 *bottom = os::Linux::initial_thread_stack_bottom();
698 *size = os::Linux::initial_thread_stack_size();
699 } else {
700 pthread_attr_t attr;
701
702 int rslt = pthread_getattr_np(pthread_self(), &attr);
703
704 // JVM needs to know exact stack location, abort if it fails
705 if (rslt != 0) {
706 if (rslt == ENOMEM) {
707 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
708 } else {
709 fatal(err_msg("pthread_getattr_np failed with errno = %d", rslt));
710 }
711 }
712
713 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
714 fatal("Can not locate current stack attributes!");
715 }
716
717 pthread_attr_destroy(&attr);
718
719 }
720 assert(os::current_stack_pointer() >= *bottom &&
721 os::current_stack_pointer() < *bottom + *size, "just checking");
722 }
723
724 address os::current_stack_base() {
725 address bottom;
726 size_t size;
727 current_stack_region(&bottom, &size);
728 return (bottom + size);
729 }
730
731 size_t os::current_stack_size() {
732 // stack size includes normal stack and HotSpot guard pages
733 address bottom;
734 size_t size;
735 current_stack_region(&bottom, &size);
736 return size;
737 }
738
739 /////////////////////////////////////////////////////////////////////////////
740 // helper functions for fatal error handler
741
742 void os::print_context(outputStream *st, void *context) {
743 if (context == NULL) return;
744
745 ucontext_t *uc = (ucontext_t*)context;
746 st->print_cr("Registers:");
747 #ifdef AMD64
748 st->print( "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
749 st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
750 st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
751 st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
752 st->cr();
753 st->print( "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
754 st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
755 st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
756 st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
757 st->cr();
758 st->print( "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
759 st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
760 st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
761 st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
762 st->cr();
763 st->print( "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
764 st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
765 st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
766 st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
767 st->cr();
768 st->print( "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
769 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
770 st->print(", CSGSFS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_CSGSFS]);
771 st->print(", ERR=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ERR]);
772 st->cr();
773 st->print(" TRAPNO=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_TRAPNO]);
774 #else
775 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
776 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
777 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
778 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
779 st->cr();
780 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
781 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
782 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
783 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
784 st->cr();
785 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
786 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
787 st->print(", CR2=" INTPTR_FORMAT, uc->uc_mcontext.cr2);
788 #endif // AMD64
789 st->cr();
790 st->cr();
791
792 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
793 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
794 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
795 st->cr();
796
797 // Note: it may be unsafe to inspect memory near pc. For example, pc may
798 // point to garbage if entry point in an nmethod is corrupted. Leave
799 // this at the end, and hope for the best.
800 address pc = os::Linux::ucontext_get_pc(uc);
801 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
802 print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
803 }
804
805 void os::print_register_info(outputStream *st, void *context) {
806 if (context == NULL) return;
807
808 ucontext_t *uc = (ucontext_t*)context;
809
810 st->print_cr("Register to memory mapping:");
811 st->cr();
812
813 // this is horrendously verbose but the layout of the registers in the
814 // context does not match how we defined our abstract Register set, so
815 // we can't just iterate through the gregs area
816
817 // this is only for the "general purpose" registers
818
819 #ifdef AMD64
820 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
821 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
822 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
823 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
824 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
825 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
826 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
827 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
828 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
829 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
830 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
831 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
832 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
833 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
834 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
835 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
836 #else
837 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
838 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
839 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
840 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
841 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
842 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
843 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
844 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
845 #endif // AMD64
846
847 st->cr();
848 }
849
850 void os::setup_fpu() {
851 #ifndef AMD64
852 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
853 __asm__ volatile ( "fldcw (%0)" :
854 : "r" (fpu_cntrl) : "memory");
855 #endif // !AMD64
856 }
857
858 #ifndef PRODUCT
859 void os::verify_stack_alignment() {
860 #ifdef AMD64
861 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
862 #endif
863 }
864 #endif