Tue, 04 Jun 2013 22:16:15 -0700
8015252: Enable HotSpot build with Clang
Reviewed-by: twisti, dholmes, kvn
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 */
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"
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>
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
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 }
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).
111 return (char*) -1;
112 }
114 void os::initialize_thread(Thread* thr) {
115 // Nothing to do.
116 }
118 address os::Linux::ucontext_get_pc(ucontext_t * uc) {
119 return (address)uc->uc_mcontext.gregs[REG_PC];
120 }
122 intptr_t* os::Linux::ucontext_get_sp(ucontext_t * uc) {
123 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
124 }
126 intptr_t* os::Linux::ucontext_get_fp(ucontext_t * uc) {
127 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
128 }
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) {
138 assert(thread != NULL, "just checking");
139 assert(ret_sp != NULL, "just checking");
140 assert(ret_fp != NULL, "just checking");
142 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
143 }
145 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
146 intptr_t** ret_sp, intptr_t** ret_fp) {
148 ExtendedPC epc;
149 ucontext_t* uc = (ucontext_t*)ucVoid;
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 }
162 return epc;
163 }
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 }
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 }
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 }
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 }
205 // Utility functions
207 // From IA32 System Programming Guide
208 enum {
209 trap_page_fault = 0xE
210 };
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
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;
226 Thread* t = ThreadLocalStorage::get_thread_slow();
228 SignalHandlerMark shm(t);
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.
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 }
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;
275 address pc = NULL;
277 //%note os_trap_1
278 if (info != NULL && uc != NULL && thread != NULL) {
279 pc = (address) os::Linux::ucontext_get_pc(uc);
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
292 // Handle ALL stack overflow variations here
293 if (sig == SIGSEGV) {
294 address addr = (address) info->si_addr;
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.");
316 // This is a likely cause, but hard to verify. Let's just print
317 // it as a hint.
318 tty->print_raw_cr("Please check if any of your loaded .so files has "
319 "enabled executable stack (see man page execstack(8))");
320 } else {
321 // Accessing stack address below sp may cause SEGV if current
322 // thread has MAP_GROWSDOWN stack. This should only happen when
323 // current thread was created by user code with MAP_GROWSDOWN flag
324 // and then attached to VM. See notes in os_linux.cpp.
325 if (thread->osthread()->expanding_stack() == 0) {
326 thread->osthread()->set_expanding_stack();
327 if (os::Linux::manually_expand_stack(thread, addr)) {
328 thread->osthread()->clear_expanding_stack();
329 return 1;
330 }
331 thread->osthread()->clear_expanding_stack();
332 } else {
333 fatal("recursive segv. expanding stack.");
334 }
335 }
336 }
337 }
339 if (thread->thread_state() == _thread_in_Java) {
340 // Java thread running in Java code => find exception handler if any
341 // a fault inside compiled code, the interpreter, or a stub
343 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
344 stub = SharedRuntime::get_poll_stub(pc);
345 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
346 // BugId 4454115: A read from a MappedByteBuffer can fault
347 // here if the underlying file has been truncated.
348 // Do not crash the VM in such a case.
349 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
350 nmethod* nm = (cb != NULL && cb->is_nmethod()) ? (nmethod*)cb : NULL;
351 if (nm != NULL && nm->has_unsafe_access()) {
352 stub = StubRoutines::handler_for_unsafe_access();
353 }
354 }
355 else
357 #ifdef AMD64
358 if (sig == SIGFPE &&
359 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
360 stub =
361 SharedRuntime::
362 continuation_for_implicit_exception(thread,
363 pc,
364 SharedRuntime::
365 IMPLICIT_DIVIDE_BY_ZERO);
366 #else
367 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
368 // HACK: si_code does not work on linux 2.2.12-20!!!
369 int op = pc[0];
370 if (op == 0xDB) {
371 // FIST
372 // TODO: The encoding of D2I in i486.ad can cause an exception
373 // prior to the fist instruction if there was an invalid operation
374 // pending. We want to dismiss that exception. From the win_32
375 // side it also seems that if it really was the fist causing
376 // the exception that we do the d2i by hand with different
377 // rounding. Seems kind of weird.
378 // NOTE: that we take the exception at the NEXT floating point instruction.
379 assert(pc[0] == 0xDB, "not a FIST opcode");
380 assert(pc[1] == 0x14, "not a FIST opcode");
381 assert(pc[2] == 0x24, "not a FIST opcode");
382 return true;
383 } else if (op == 0xF7) {
384 // IDIV
385 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
386 } else {
387 // TODO: handle more cases if we are using other x86 instructions
388 // that can generate SIGFPE signal on linux.
389 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
390 fatal("please update this code.");
391 }
392 #endif // AMD64
393 } else if (sig == SIGSEGV &&
394 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
395 // Determination of interpreter/vtable stub/compiled code null exception
396 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
397 }
398 } else if (thread->thread_state() == _thread_in_vm &&
399 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
400 thread->doing_unsafe_access()) {
401 stub = StubRoutines::handler_for_unsafe_access();
402 }
404 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
405 // and the heap gets shrunk before the field access.
406 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
407 address addr = JNI_FastGetField::find_slowcase_pc(pc);
408 if (addr != (address)-1) {
409 stub = addr;
410 }
411 }
413 // Check to see if we caught the safepoint code in the
414 // process of write protecting the memory serialization page.
415 // It write enables the page immediately after protecting it
416 // so we can just return to retry the write.
417 if ((sig == SIGSEGV) &&
418 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
419 // Block current thread until the memory serialize page permission restored.
420 os::block_on_serialize_page_trap();
421 return true;
422 }
423 }
425 #ifndef AMD64
426 // Execution protection violation
427 //
428 // This should be kept as the last step in the triage. We don't
429 // have a dedicated trap number for a no-execute fault, so be
430 // conservative and allow other handlers the first shot.
431 //
432 // Note: We don't test that info->si_code == SEGV_ACCERR here.
433 // this si_code is so generic that it is almost meaningless; and
434 // the si_code for this condition may change in the future.
435 // Furthermore, a false-positive should be harmless.
436 if (UnguardOnExecutionViolation > 0 &&
437 (sig == SIGSEGV || sig == SIGBUS) &&
438 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
439 int page_size = os::vm_page_size();
440 address addr = (address) info->si_addr;
441 address pc = os::Linux::ucontext_get_pc(uc);
442 // Make sure the pc and the faulting address are sane.
443 //
444 // If an instruction spans a page boundary, and the page containing
445 // the beginning of the instruction is executable but the following
446 // page is not, the pc and the faulting address might be slightly
447 // different - we still want to unguard the 2nd page in this case.
448 //
449 // 15 bytes seems to be a (very) safe value for max instruction size.
450 bool pc_is_near_addr =
451 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
452 bool instr_spans_page_boundary =
453 (align_size_down((intptr_t) pc ^ (intptr_t) addr,
454 (intptr_t) page_size) > 0);
456 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
457 static volatile address last_addr =
458 (address) os::non_memory_address_word();
460 // In conservative mode, don't unguard unless the address is in the VM
461 if (addr != last_addr &&
462 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
464 // Set memory to RWX and retry
465 address page_start =
466 (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
467 bool res = os::protect_memory((char*) page_start, page_size,
468 os::MEM_PROT_RWX);
470 if (PrintMiscellaneous && Verbose) {
471 char buf[256];
472 jio_snprintf(buf, sizeof(buf), "Execution protection violation "
473 "at " INTPTR_FORMAT
474 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,
475 page_start, (res ? "success" : "failed"), errno);
476 tty->print_raw_cr(buf);
477 }
478 stub = pc;
480 // Set last_addr so if we fault again at the same address, we don't end
481 // up in an endless loop.
482 //
483 // There are two potential complications here. Two threads trapping at
484 // the same address at the same time could cause one of the threads to
485 // think it already unguarded, and abort the VM. Likely very rare.
486 //
487 // The other race involves two threads alternately trapping at
488 // different addresses and failing to unguard the page, resulting in
489 // an endless loop. This condition is probably even more unlikely than
490 // the first.
491 //
492 // Although both cases could be avoided by using locks or thread local
493 // last_addr, these solutions are unnecessary complication: this
494 // handler is a best-effort safety net, not a complete solution. It is
495 // disabled by default and should only be used as a workaround in case
496 // we missed any no-execute-unsafe VM code.
498 last_addr = addr;
499 }
500 }
501 }
502 #endif // !AMD64
504 if (stub != NULL) {
505 // save all thread context in case we need to restore it
506 if (thread != NULL) thread->set_saved_exception_pc(pc);
508 uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub;
509 return true;
510 }
512 // signal-chaining
513 if (os::Linux::chained_handler(sig, info, ucVoid)) {
514 return true;
515 }
517 if (!abort_if_unrecognized) {
518 // caller wants another chance, so give it to him
519 return false;
520 }
522 if (pc == NULL && uc != NULL) {
523 pc = os::Linux::ucontext_get_pc(uc);
524 }
526 // unmask current signal
527 sigset_t newset;
528 sigemptyset(&newset);
529 sigaddset(&newset, sig);
530 sigprocmask(SIG_UNBLOCK, &newset, NULL);
532 VMError err(t, sig, pc, info, ucVoid);
533 err.report_and_die();
535 ShouldNotReachHere();
536 }
538 void os::Linux::init_thread_fpu_state(void) {
539 #ifndef AMD64
540 // set fpu to 53 bit precision
541 set_fpu_control_word(0x27f);
542 #endif // !AMD64
543 }
545 int os::Linux::get_fpu_control_word(void) {
546 #ifdef AMD64
547 return 0;
548 #else
549 int fpu_control;
550 _FPU_GETCW(fpu_control);
551 return fpu_control & 0xffff;
552 #endif // AMD64
553 }
555 void os::Linux::set_fpu_control_word(int fpu_control) {
556 #ifndef AMD64
557 _FPU_SETCW(fpu_control);
558 #endif // !AMD64
559 }
561 // Check that the linux kernel version is 2.4 or higher since earlier
562 // versions do not support SSE without patches.
563 bool os::supports_sse() {
564 #ifdef AMD64
565 return true;
566 #else
567 struct utsname uts;
568 if( uname(&uts) != 0 ) return false; // uname fails?
569 char *minor_string;
570 int major = strtol(uts.release,&minor_string,10);
571 int minor = strtol(minor_string+1,NULL,10);
572 bool result = (major > 2 || (major==2 && minor >= 4));
573 #ifndef PRODUCT
574 if (PrintMiscellaneous && Verbose) {
575 tty->print("OS version is %d.%d, which %s support SSE/SSE2\n",
576 major,minor, result ? "DOES" : "does NOT");
577 }
578 #endif
579 return result;
580 #endif // AMD64
581 }
583 bool os::is_allocatable(size_t bytes) {
584 #ifdef AMD64
585 // unused on amd64?
586 return true;
587 #else
589 if (bytes < 2 * G) {
590 return true;
591 }
593 char* addr = reserve_memory(bytes, NULL);
595 if (addr != NULL) {
596 release_memory(addr, bytes);
597 }
599 return addr != NULL;
600 #endif // AMD64
601 }
603 ////////////////////////////////////////////////////////////////////////////////
604 // thread stack
606 #ifdef AMD64
607 size_t os::Linux::min_stack_allowed = 64 * K;
609 // amd64: pthread on amd64 is always in floating stack mode
610 bool os::Linux::supports_variable_stack_size() { return true; }
611 #else
612 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K;
614 #ifdef __GNUC__
615 #define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})
616 #endif
618 // Test if pthread library can support variable thread stack size. LinuxThreads
619 // in fixed stack mode allocates 2M fixed slot for each thread. LinuxThreads
620 // in floating stack mode and NPTL support variable stack size.
621 bool os::Linux::supports_variable_stack_size() {
622 if (os::Linux::is_NPTL()) {
623 // NPTL, yes
624 return true;
626 } else {
627 // Note: We can't control default stack size when creating a thread.
628 // If we use non-default stack size (pthread_attr_setstacksize), both
629 // floating stack and non-floating stack LinuxThreads will return the
630 // same value. This makes it impossible to implement this function by
631 // detecting thread stack size directly.
632 //
633 // An alternative approach is to check %gs. Fixed-stack LinuxThreads
634 // do not use %gs, so its value is 0. Floating-stack LinuxThreads use
635 // %gs (either as LDT selector or GDT selector, depending on kernel)
636 // to access thread specific data.
637 //
638 // Note that %gs is a reserved glibc register since early 2001, so
639 // applications are not allowed to change its value (Ulrich Drepper from
640 // Redhat confirmed that all known offenders have been modified to use
641 // either %fs or TSD). In the worst case scenario, when VM is embedded in
642 // a native application that plays with %gs, we might see non-zero %gs
643 // even LinuxThreads is running in fixed stack mode. As the result, we'll
644 // return true and skip _thread_safety_check(), so we may not be able to
645 // detect stack-heap collisions. But otherwise it's harmless.
646 //
647 #ifdef __GNUC__
648 return (GET_GS() != 0);
649 #else
650 return false;
651 #endif
652 }
653 }
654 #endif // AMD64
656 // return default stack size for thr_type
657 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
658 // default stack size (compiler thread needs larger stack)
659 #ifdef AMD64
660 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
661 #else
662 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
663 #endif // AMD64
664 return s;
665 }
667 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
668 // Creating guard page is very expensive. Java thread has HotSpot
669 // guard page, only enable glibc guard page for non-Java threads.
670 return (thr_type == java_thread ? 0 : page_size());
671 }
673 // Java thread:
674 //
675 // Low memory addresses
676 // +------------------------+
677 // | |\ JavaThread created by VM does not have glibc
678 // | glibc guard page | - guard, attached Java thread usually has
679 // | |/ 1 page glibc guard.
680 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
681 // | |\
682 // | HotSpot Guard Pages | - red and yellow pages
683 // | |/
684 // +------------------------+ JavaThread::stack_yellow_zone_base()
685 // | |\
686 // | Normal Stack | -
687 // | |/
688 // P2 +------------------------+ Thread::stack_base()
689 //
690 // Non-Java thread:
691 //
692 // Low memory addresses
693 // +------------------------+
694 // | |\
695 // | glibc guard page | - usually 1 page
696 // | |/
697 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
698 // | |\
699 // | Normal Stack | -
700 // | |/
701 // P2 +------------------------+ Thread::stack_base()
702 //
703 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
704 // pthread_attr_getstack()
706 static void current_stack_region(address * bottom, size_t * size) {
707 if (os::Linux::is_initial_thread()) {
708 // initial thread needs special handling because pthread_getattr_np()
709 // may return bogus value.
710 *bottom = os::Linux::initial_thread_stack_bottom();
711 *size = os::Linux::initial_thread_stack_size();
712 } else {
713 pthread_attr_t attr;
715 int rslt = pthread_getattr_np(pthread_self(), &attr);
717 // JVM needs to know exact stack location, abort if it fails
718 if (rslt != 0) {
719 if (rslt == ENOMEM) {
720 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
721 } else {
722 fatal(err_msg("pthread_getattr_np failed with errno = %d", rslt));
723 }
724 }
726 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
727 fatal("Can not locate current stack attributes!");
728 }
730 pthread_attr_destroy(&attr);
732 }
733 assert(os::current_stack_pointer() >= *bottom &&
734 os::current_stack_pointer() < *bottom + *size, "just checking");
735 }
737 address os::current_stack_base() {
738 address bottom;
739 size_t size;
740 current_stack_region(&bottom, &size);
741 return (bottom + size);
742 }
744 size_t os::current_stack_size() {
745 // stack size includes normal stack and HotSpot guard pages
746 address bottom;
747 size_t size;
748 current_stack_region(&bottom, &size);
749 return size;
750 }
752 /////////////////////////////////////////////////////////////////////////////
753 // helper functions for fatal error handler
755 void os::print_context(outputStream *st, void *context) {
756 if (context == NULL) return;
758 ucontext_t *uc = (ucontext_t*)context;
759 st->print_cr("Registers:");
760 #ifdef AMD64
761 st->print( "RAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RAX]);
762 st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
763 st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
764 st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
765 st->cr();
766 st->print( "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
767 st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
768 st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
769 st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
770 st->cr();
771 st->print( "R8 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
772 st->print(", R9 =" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
773 st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
774 st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
775 st->cr();
776 st->print( "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
777 st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
778 st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
779 st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
780 st->cr();
781 st->print( "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
782 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
783 st->print(", CSGSFS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_CSGSFS]);
784 st->print(", ERR=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ERR]);
785 st->cr();
786 st->print(" TRAPNO=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_TRAPNO]);
787 #else
788 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
789 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
790 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
791 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
792 st->cr();
793 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
794 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
795 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
796 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
797 st->cr();
798 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
799 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
800 st->print(", CR2=" INTPTR_FORMAT, uc->uc_mcontext.cr2);
801 #endif // AMD64
802 st->cr();
803 st->cr();
805 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
806 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
807 print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));
808 st->cr();
810 // Note: it may be unsafe to inspect memory near pc. For example, pc may
811 // point to garbage if entry point in an nmethod is corrupted. Leave
812 // this at the end, and hope for the best.
813 address pc = os::Linux::ucontext_get_pc(uc);
814 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
815 print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
816 }
818 void os::print_register_info(outputStream *st, void *context) {
819 if (context == NULL) return;
821 ucontext_t *uc = (ucontext_t*)context;
823 st->print_cr("Register to memory mapping:");
824 st->cr();
826 // this is horrendously verbose but the layout of the registers in the
827 // context does not match how we defined our abstract Register set, so
828 // we can't just iterate through the gregs area
830 // this is only for the "general purpose" registers
832 #ifdef AMD64
833 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
834 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
835 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
836 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
837 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
838 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
839 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
840 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
841 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
842 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
843 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
844 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
845 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
846 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
847 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
848 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
849 #else
850 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
851 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
852 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
853 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
854 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
855 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
856 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
857 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
858 #endif // AMD64
860 st->cr();
861 }
863 void os::setup_fpu() {
864 #ifndef AMD64
865 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
866 __asm__ volatile ( "fldcw (%0)" :
867 : "r" (fpu_cntrl) : "memory");
868 #endif // !AMD64
869 }
871 #ifndef PRODUCT
872 void os::verify_stack_alignment() {
873 #ifdef AMD64
874 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
875 #endif
876 }
877 #endif