1 /*
2 * Copyright (c) 1999, 2016, 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/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "code/vtableStubs.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "memory/allocation.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 "services/memTracker.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 #elif defined(__clang__)
98 intptr_t* esp;
99 __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):);
100 return (address) esp;
101 #else
102 register void *esp __asm__ (SPELL_REG_SP);
103 return (address) esp;
104 #endif
105 }
106
107 char* os::non_memory_address_word() {
108 // Must never look like an address returned by reserve_memory,
109 // even in its subfields (as defined by the CPU immediate fields,
110 // if the CPU splits constants across multiple instructions).
111
112 return (char*) -1;
113 }
114
115 void os::initialize_thread(Thread* thr) {
116 // Nothing to do.
117 }
118
119 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
120 return (address)uc->uc_mcontext.gregs[REG_PC];
121 }
122
123 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
124 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc;
125 }
126
127 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
128 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
129 }
130
131 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
132 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
133 }
134
135 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
136 // is currently interrupted by SIGPROF.
137 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
138 // frames. Currently we don't do that on Linux, so it's the same as
139 // os::fetch_frame_from_context().
140 // This method is also used for stack overflow signal handling.
141 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
142 const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
143
144 assert(thread != NULL, "just checking");
145 assert(ret_sp != NULL, "just checking");
146 assert(ret_fp != NULL, "just checking");
147
148 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
149 }
150
151 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
152 intptr_t** ret_sp, intptr_t** ret_fp) {
153
154 ExtendedPC epc;
155 const ucontext_t* uc = (const ucontext_t*)ucVoid;
156
157 if (uc != NULL) {
158 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
159 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
160 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
161 } else {
162 // construct empty ExtendedPC for return value checking
163 epc = ExtendedPC(NULL);
164 if (ret_sp) *ret_sp = (intptr_t *)NULL;
165 if (ret_fp) *ret_fp = (intptr_t *)NULL;
166 }
167
168 return epc;
169 }
170
171 frame os::fetch_frame_from_context(const void* ucVoid) {
172 intptr_t* sp;
173 intptr_t* fp;
174 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
175 return frame(sp, fp, epc.pc());
176 }
177
178 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
179 intptr_t* sp;
180 intptr_t* fp;
181 ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp);
182 return frame(sp, fp, epc.pc());
183 }
184
185 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
186 address pc = (address) os::Linux::ucontext_get_pc(uc);
187 if (Interpreter::contains(pc)) {
188 // interpreter performs stack banging after the fixed frame header has
189 // been generated while the compilers perform it before. To maintain
190 // semantic consistency between interpreted and compiled frames, the
191 // method returns the Java sender of the current frame.
192 *fr = os::fetch_frame_from_ucontext(thread, uc);
193 if (!fr->is_first_java_frame()) {
194 assert(fr->safe_for_sender(thread), "Safety check");
195 *fr = fr->java_sender();
196 }
197 } else {
198 // more complex code with compiled code
199 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
200 CodeBlob* cb = CodeCache::find_blob(pc);
201 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
202 // Not sure where the pc points to, fallback to default
203 // stack overflow handling
204 return false;
205 } else {
206 // in compiled code, the stack banging is performed just after the return pc
207 // has been pushed on the stack
208 intptr_t* fp = os::Linux::ucontext_get_fp(uc);
209 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
210 *fr = frame(sp + 1, fp, (address)*sp);
211 if (!fr->is_java_frame()) {
212 assert(fr->safe_for_sender(thread), "Safety check");
213 assert(!fr->is_first_frame(), "Safety check");
214 *fr = fr->java_sender();
215 }
216 }
217 }
218 assert(fr->is_java_frame(), "Safety check");
219 return true;
220 }
221
222 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
223 // turned off by -fomit-frame-pointer,
224 frame os::get_sender_for_C_frame(frame* fr) {
225 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
226 }
227
228 intptr_t* _get_previous_fp() {
229 #ifdef SPARC_WORKS
230 register intptr_t **ebp;
231 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
232 #elif defined(__clang__)
233 intptr_t **ebp;
234 __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):);
235 #else
236 register intptr_t **ebp __asm__ (SPELL_REG_FP);
237 #endif
238 return (intptr_t*) *ebp; // we want what it points to.
239 }
240
241
242 frame os::current_frame() {
243 intptr_t* fp = _get_previous_fp();
244 frame myframe((intptr_t*)os::current_stack_pointer(),
245 (intptr_t*)fp,
246 CAST_FROM_FN_PTR(address, os::current_frame));
247 if (os::is_first_C_frame(&myframe)) {
248 // stack is not walkable
249 return frame();
250 } else {
251 return os::get_sender_for_C_frame(&myframe);
252 }
253 }
254
255 // Utility functions
256
257 // From IA32 System Programming Guide
258 enum {
259 trap_page_fault = 0xE
260 };
261
262 extern "C" JNIEXPORT int
263 JVM_handle_linux_signal(int sig,
264 siginfo_t* info,
265 void* ucVoid,
266 int abort_if_unrecognized) {
267 ucontext_t* uc = (ucontext_t*) ucVoid;
268
269 Thread* t = Thread::current_or_null_safe();
270
271 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
272 // (no destructors can be run)
273 os::WatcherThreadCrashProtection::check_crash_protection(sig, t);
274
275 SignalHandlerMark shm(t);
276
277 // Note: it's not uncommon that JNI code uses signal/sigset to install
278 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
279 // or have a SIGILL handler when detecting CPU type). When that happens,
280 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
281 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
282 // that do not require siginfo/ucontext first.
283
284 if (sig == SIGPIPE || sig == SIGXFSZ) {
285 // allow chained handler to go first
286 if (os::Linux::chained_handler(sig, info, ucVoid)) {
287 return true;
288 } else {
289 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
290 return true;
291 }
292 }
293
294 JavaThread* thread = NULL;
295 VMThread* vmthread = NULL;
296 if (os::Linux::signal_handlers_are_installed) {
297 if (t != NULL ){
298 if(t->is_Java_thread()) {
299 thread = (JavaThread*)t;
300 }
301 else if(t->is_VM_thread()){
302 vmthread = (VMThread *)t;
303 }
304 }
305 }
306 /*
307 NOTE: does not seem to work on linux.
308 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
309 // can't decode this kind of signal
310 info = NULL;
311 } else {
312 assert(sig == info->si_signo, "bad siginfo");
313 }
314 */
315 // decide if this trap can be handled by a stub
316 address stub = NULL;
317
318 address pc = NULL;
319
320 //%note os_trap_1
321 if (info != NULL && uc != NULL && thread != NULL) {
322 pc = (address) os::Linux::ucontext_get_pc(uc);
323
324 if (StubRoutines::is_safefetch_fault(pc)) {
325 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
326 return 1;
327 }
328
329 #ifndef AMD64
330 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs
331 // This can happen in any running code (currently more frequently in
332 // interpreter code but has been seen in compiled code)
333 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) {
334 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due "
335 "to unstable signal handling in this distribution.");
336 }
337 #endif // AMD64
338
339 // Handle ALL stack overflow variations here
340 if (sig == SIGSEGV) {
341 address addr = (address) info->si_addr;
342
343 // check if fault address is within thread stack
344 if (thread->on_local_stack(addr)) {
345 // stack overflow
346 if (thread->in_stack_yellow_reserved_zone(addr)) {
347 if (thread->thread_state() == _thread_in_Java) {
348 if (thread->in_stack_reserved_zone(addr)) {
349 frame fr;
350 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
351 assert(fr.is_java_frame(), "Must be a Java frame");
352 frame activation =
353 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
354 if (activation.sp() != NULL) {
355 thread->disable_stack_reserved_zone();
356 if (activation.is_interpreted_frame()) {
357 thread->set_reserved_stack_activation((address)(
358 activation.fp() + frame::interpreter_frame_initial_sp_offset));
359 } else {
360 thread->set_reserved_stack_activation((address)activation.unextended_sp());
361 }
362 return 1;
363 }
364 }
365 }
366 // Throw a stack overflow exception. Guard pages will be reenabled
367 // while unwinding the stack.
368 thread->disable_stack_yellow_reserved_zone();
369 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
370 } else {
371 // Thread was in the vm or native code. Return and try to finish.
372 thread->disable_stack_yellow_reserved_zone();
373 return 1;
374 }
375 } else if (thread->in_stack_red_zone(addr)) {
376 // Fatal red zone violation. Disable the guard pages and fall through
377 // to handle_unexpected_exception way down below.
378 thread->disable_stack_red_zone();
379 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
380
381 // This is a likely cause, but hard to verify. Let's just print
382 // it as a hint.
383 tty->print_raw_cr("Please check if any of your loaded .so files has "
384 "enabled executable stack (see man page execstack(8))");
385 } else {
386 // Accessing stack address below sp may cause SEGV if current
387 // thread has MAP_GROWSDOWN stack. This should only happen when
388 // current thread was created by user code with MAP_GROWSDOWN flag
389 // and then attached to VM. See notes in os_linux.cpp.
390 if (thread->osthread()->expanding_stack() == 0) {
391 thread->osthread()->set_expanding_stack();
392 if (os::Linux::manually_expand_stack(thread, addr)) {
393 thread->osthread()->clear_expanding_stack();
394 return 1;
395 }
396 thread->osthread()->clear_expanding_stack();
397 } else {
398 fatal("recursive segv. expanding stack.");
399 }
400 }
401 }
402 }
403
404 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) {
405 // Verify that OS save/restore AVX registers.
406 stub = VM_Version::cpuinfo_cont_addr();
407 }
408
409 if (thread->thread_state() == _thread_in_Java) {
410 // Java thread running in Java code => find exception handler if any
411 // a fault inside compiled code, the interpreter, or a stub
412
413 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
414 stub = SharedRuntime::get_poll_stub(pc);
415 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
416 // BugId 4454115: A read from a MappedByteBuffer can fault
417 // here if the underlying file has been truncated.
418 // Do not crash the VM in such a case.
419 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
420 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
421 if (nm != NULL && nm->has_unsafe_access()) {
422 address next_pc = Assembler::locate_next_instruction(pc);
423 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
424 }
425 }
426 else
427
428 #ifdef AMD64
429 if (sig == SIGFPE &&
430 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
431 stub =
432 SharedRuntime::
433 continuation_for_implicit_exception(thread,
434 pc,
435 SharedRuntime::
436 IMPLICIT_DIVIDE_BY_ZERO);
437 #else
438 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
439 // HACK: si_code does not work on linux 2.2.12-20!!!
440 int op = pc[0];
441 if (op == 0xDB) {
442 // FIST
443 // TODO: The encoding of D2I in i486.ad can cause an exception
444 // prior to the fist instruction if there was an invalid operation
445 // pending. We want to dismiss that exception. From the win_32
446 // side it also seems that if it really was the fist causing
447 // the exception that we do the d2i by hand with different
448 // rounding. Seems kind of weird.
449 // NOTE: that we take the exception at the NEXT floating point instruction.
450 assert(pc[0] == 0xDB, "not a FIST opcode");
451 assert(pc[1] == 0x14, "not a FIST opcode");
452 assert(pc[2] == 0x24, "not a FIST opcode");
453 return true;
454 } else if (op == 0xF7) {
455 // IDIV
456 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
457 } else {
458 // TODO: handle more cases if we are using other x86 instructions
459 // that can generate SIGFPE signal on linux.
460 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
461 fatal("please update this code.");
462 }
463 #endif // AMD64
464 } else if (sig == SIGSEGV &&
465 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
466 // Determination of interpreter/vtable stub/compiled code null exception
467 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
468 }
469 } else if (thread->thread_state() == _thread_in_vm &&
470 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
471 thread->doing_unsafe_access()) {
472 address next_pc = Assembler::locate_next_instruction(pc);
473 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
474 }
475
476 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
477 // and the heap gets shrunk before the field access.
478 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
479 address addr = JNI_FastGetField::find_slowcase_pc(pc);
480 if (addr != (address)-1) {
481 stub = addr;
482 }
483 }
484
485 // Check to see if we caught the safepoint code in the
486 // process of write protecting the memory serialization page.
487 // It write enables the page immediately after protecting it
488 // so we can just return to retry the write.
489 if ((sig == SIGSEGV) &&
490 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
491 // Block current thread until the memory serialize page permission restored.
492 os::block_on_serialize_page_trap();
493 return true;
494 }
495 }
496
497 #ifndef AMD64
498 // Execution protection violation
499 //
500 // This should be kept as the last step in the triage. We don't
501 // have a dedicated trap number for a no-execute fault, so be
502 // conservative and allow other handlers the first shot.
503 //
504 // Note: We don't test that info->si_code == SEGV_ACCERR here.
505 // this si_code is so generic that it is almost meaningless; and
506 // the si_code for this condition may change in the future.
507 // Furthermore, a false-positive should be harmless.
508 if (UnguardOnExecutionViolation > 0 &&
509 (sig == SIGSEGV || sig == SIGBUS) &&
510 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
511 int page_size = os::vm_page_size();
512 address addr = (address) info->si_addr;
513 address pc = os::Linux::ucontext_get_pc(uc);
514 // Make sure the pc and the faulting address are sane.
515 //
516 // If an instruction spans a page boundary, and the page containing
517 // the beginning of the instruction is executable but the following
518 // page is not, the pc and the faulting address might be slightly
519 // different - we still want to unguard the 2nd page in this case.
520 //
521 // 15 bytes seems to be a (very) safe value for max instruction size.
522 bool pc_is_near_addr =
523 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
524 bool instr_spans_page_boundary =
525 (align_size_down((intptr_t) pc ^ (intptr_t) addr,
526 (intptr_t) page_size) > 0);
527
528 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
529 static volatile address last_addr =
530 (address) os::non_memory_address_word();
531
532 // In conservative mode, don't unguard unless the address is in the VM
533 if (addr != last_addr &&
534 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
535
536 // Set memory to RWX and retry
537 address page_start =
538 (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
539 bool res = os::protect_memory((char*) page_start, page_size,
540 os::MEM_PROT_RWX);
541
542 log_debug(os)("Execution protection violation "
543 "at " INTPTR_FORMAT
544 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
545 p2i(page_start), (res ? "success" : "failed"), errno);
546 stub = pc;
547
548 // Set last_addr so if we fault again at the same address, we don't end
549 // up in an endless loop.
550 //
551 // There are two potential complications here. Two threads trapping at
552 // the same address at the same time could cause one of the threads to
553 // think it already unguarded, and abort the VM. Likely very rare.
554 //
555 // The other race involves two threads alternately trapping at
556 // different addresses and failing to unguard the page, resulting in
557 // an endless loop. This condition is probably even more unlikely than
558 // the first.
559 //
560 // Although both cases could be avoided by using locks or thread local
561 // last_addr, these solutions are unnecessary complication: this
562 // handler is a best-effort safety net, not a complete solution. It is
563 // disabled by default and should only be used as a workaround in case
564 // we missed any no-execute-unsafe VM code.
565
566 last_addr = addr;
567 }
568 }
569 }
570 #endif // !AMD64
571
572 if (stub != NULL) {
573 // save all thread context in case we need to restore it
574 if (thread != NULL) thread->set_saved_exception_pc(pc);
575
576 os::Linux::ucontext_set_pc(uc, stub);
577 return true;
578 }
579
580 // signal-chaining
581 if (os::Linux::chained_handler(sig, info, ucVoid)) {
582 return true;
583 }
584
585 if (!abort_if_unrecognized) {
586 // caller wants another chance, so give it to him
587 return false;
588 }
589
590 if (pc == NULL && uc != NULL) {
591 pc = os::Linux::ucontext_get_pc(uc);
592 }
593
594 // unmask current signal
595 sigset_t newset;
596 sigemptyset(&newset);
597 sigaddset(&newset, sig);
598 sigprocmask(SIG_UNBLOCK, &newset, NULL);
599
600 VMError::report_and_die(t, sig, pc, info, ucVoid);
601
602 ShouldNotReachHere();
603 return true; // Mute compiler
604 }
605
606 void os::Linux::init_thread_fpu_state(void) {
607 #ifndef AMD64
608 // set fpu to 53 bit precision
609 set_fpu_control_word(0x27f);
610 #endif // !AMD64
611 }
612
613 int os::Linux::get_fpu_control_word(void) {
614 #ifdef AMD64
615 return 0;
616 #else
617 int fpu_control;
618 _FPU_GETCW(fpu_control);
619 return fpu_control & 0xffff;
620 #endif // AMD64
621 }
622
623 void os::Linux::set_fpu_control_word(int fpu_control) {
624 #ifndef AMD64
625 _FPU_SETCW(fpu_control);
626 #endif // !AMD64
627 }
628
629 // Check that the linux kernel version is 2.4 or higher since earlier
630 // versions do not support SSE without patches.
631 bool os::supports_sse() {
632 #ifdef AMD64
633 return true;
634 #else
635 struct utsname uts;
636 if( uname(&uts) != 0 ) return false; // uname fails?
637 char *minor_string;
638 int major = strtol(uts.release,&minor_string,10);
639 int minor = strtol(minor_string+1,NULL,10);
640 bool result = (major > 2 || (major==2 && minor >= 4));
641 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2",
642 major,minor, result ? "DOES" : "does NOT");
643 return result;
644 #endif // AMD64
645 }
646
647 bool os::is_allocatable(size_t bytes) {
648 #ifdef AMD64
649 // unused on amd64?
650 return true;
651 #else
652
653 if (bytes < 2 * G) {
654 return true;
655 }
656
657 char* addr = reserve_memory(bytes, NULL);
658
659 if (addr != NULL) {
660 release_memory(addr, bytes);
661 }
662
663 return addr != NULL;
664 #endif // AMD64
665 }
666
667 ////////////////////////////////////////////////////////////////////////////////
668 // thread stack
669
670 #ifdef AMD64
671 size_t os::Linux::min_stack_allowed = 64 * K;
672 #else
673 size_t os::Linux::min_stack_allowed = (48 DEBUG_ONLY(+4))*K;
674 #endif // AMD64
675
676 // return default stack size for thr_type
677 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
678 // default stack size (compiler thread needs larger stack)
679 #ifdef AMD64
680 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
681 #else
682 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
683 #endif // AMD64
684 return s;
685 }
686
687 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
688 // Creating guard page is very expensive. Java thread has HotSpot
689 // guard page, only enable glibc guard page for non-Java threads.
690 return (thr_type == java_thread ? 0 : page_size());
691 }
692
693 // Java thread:
694 //
695 // Low memory addresses
696 // +------------------------+
697 // | |\ JavaThread created by VM does not have glibc
698 // | glibc guard page | - guard, attached Java thread usually has
699 // | |/ 1 page glibc guard.
700 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
701 // | |\
702 // | HotSpot Guard Pages | - red and yellow pages
703 // | |/
704 // +------------------------+ JavaThread::stack_yellow_zone_base()
705 // | |\
706 // | Normal Stack | -
707 // | |/
708 // P2 +------------------------+ Thread::stack_base()
709 //
710 // Non-Java thread:
711 //
712 // Low memory addresses
713 // +------------------------+
714 // | |\
715 // | glibc guard page | - usually 1 page
716 // | |/
717 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
718 // | |\
719 // | Normal Stack | -
720 // | |/
721 // P2 +------------------------+ Thread::stack_base()
722 //
723 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
724 // pthread_attr_getstack()
725
726 static void current_stack_region(address * bottom, size_t * size) {
727 if (os::Linux::is_initial_thread()) {
728 // initial thread needs special handling because pthread_getattr_np()
729 // may return bogus value.
730 *bottom = os::Linux::initial_thread_stack_bottom();
731 *size = os::Linux::initial_thread_stack_size();
732 } else {
733 pthread_attr_t attr;
734
735 int rslt = pthread_getattr_np(pthread_self(), &attr);
736
737 // JVM needs to know exact stack location, abort if it fails
738 if (rslt != 0) {
739 if (rslt == ENOMEM) {
740 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
741 } else {
742 fatal("pthread_getattr_np failed with errno = %d", rslt);
743 }
744 }
745
746 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
747 fatal("Can not locate current stack attributes!");
748 }
749
750 pthread_attr_destroy(&attr);
751
752 }
753 assert(os::current_stack_pointer() >= *bottom &&
754 os::current_stack_pointer() < *bottom + *size, "just checking");
755 }
756
757 address os::current_stack_base() {
758 address bottom;
759 size_t size;
760 current_stack_region(&bottom, &size);
761 return (bottom + size);
762 }
763
764 size_t os::current_stack_size() {
765 // stack size includes normal stack and HotSpot guard pages
766 address bottom;
767 size_t size;
768 current_stack_region(&bottom, &size);
769 return size;
770 }
771
772 /////////////////////////////////////////////////////////////////////////////
773 // helper functions for fatal error handler
774
775 void os::print_context(outputStream *st, const void *context) {
776 if (context == NULL) return;
777
778 const ucontext_t *uc = (const ucontext_t*)context;
779 st->print_cr("Registers:");
780 #ifdef AMD64
781 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]);
782 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]);
783 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]);
784 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]);
785 st->cr();
786 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]);
787 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]);
788 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]);
789 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]);
790 st->cr();
791 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]);
792 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]);
793 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]);
794 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]);
795 st->cr();
796 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]);
797 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]);
798 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]);
799 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]);
800 st->cr();
801 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]);
802 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]);
803 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]);
804 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]);
805 st->cr();
806 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]);
807 #else
808 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
809 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
810 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
811 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
812 st->cr();
813 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
814 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
815 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
816 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
817 st->cr();
818 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
819 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
820 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2);
821 #endif // AMD64
822 st->cr();
823 st->cr();
824
825 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
826 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
827 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t));
828 st->cr();
829
830 // Note: it may be unsafe to inspect memory near pc. For example, pc may
831 // point to garbage if entry point in an nmethod is corrupted. Leave
832 // this at the end, and hope for the best.
833 address pc = os::Linux::ucontext_get_pc(uc);
834 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
835 print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
836 }
837
838 void os::print_register_info(outputStream *st, const void *context) {
839 if (context == NULL) return;
840
841 const ucontext_t *uc = (const ucontext_t*)context;
842
843 st->print_cr("Register to memory mapping:");
844 st->cr();
845
846 // this is horrendously verbose but the layout of the registers in the
847 // context does not match how we defined our abstract Register set, so
848 // we can't just iterate through the gregs area
849
850 // this is only for the "general purpose" registers
851
852 #ifdef AMD64
853 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
854 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
855 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
856 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
857 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
858 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
859 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
860 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
861 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
862 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
863 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
864 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
865 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
866 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
867 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
868 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
869 #else
870 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
871 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
872 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
873 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
874 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
875 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
876 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
877 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
878 #endif // AMD64
879
880 st->cr();
881 }
882
883 void os::setup_fpu() {
884 #ifndef AMD64
885 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
886 __asm__ volatile ( "fldcw (%0)" :
887 : "r" (fpu_cntrl) : "memory");
888 #endif // !AMD64
889 }
890
891 #ifndef PRODUCT
892 void os::verify_stack_alignment() {
893 #ifdef AMD64
894 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
895 #endif
896 }
897 #endif
898
899
900 /*
901 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit
902 * updates (JDK-8023956).
903 */
904 void os::workaround_expand_exec_shield_cs_limit() {
905 #if defined(IA32)
906 size_t page_size = os::vm_page_size();
907 /*
908 * Take the highest VA the OS will give us and exec
909 *
910 * Although using -(pagesz) as mmap hint works on newer kernel as you would
911 * think, older variants affected by this work-around don't (search forward only).
912 *
913 * On the affected distributions, we understand the memory layout to be:
914 *
915 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT.
916 *
917 * A few pages south main stack will do it.
918 *
919 * If we are embedded in an app other than launcher (initial != main stack),
920 * we don't have much control or understanding of the address space, just let it slide.
921 */
922 char* hint = (char*)(Linux::initial_thread_stack_bottom() -
923 (JavaThread::stack_guard_zone_size() + page_size));
924 char* codebuf = os::attempt_reserve_memory_at(page_size, hint);
925 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) {
926 return; // No matter, we tried, best effort.
927 }
928
929 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal);
930
931 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf);
932
933 // Some code to exec: the 'ret' instruction
934 codebuf[0] = 0xC3;
935
936 // Call the code in the codebuf
937 __asm__ volatile("call *%0" : : "r"(codebuf));
938
939 // keep the page mapped so CS limit isn't reduced.
940 #endif
941 }
942
943 int os::extra_bang_size_in_bytes() {
944 // JDK-8050147 requires the full cache line bang for x86.
945 return VM_Version::L1_line_size();
946 }