1 /*
2 * Copyright (c) 1999, 2020, 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 "jvm.h"
27 #include "asm/macroAssembler.hpp"
28 #include "classfile/classLoader.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/codeCache.hpp"
32 #include "code/icBuffer.hpp"
33 #include "code/vtableStubs.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "logging/log.hpp"
36 #include "memory/allocation.inline.hpp"
37 #include "os_share_linux.hpp"
38 #include "prims/jniFastGetField.hpp"
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.inline.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/align.hpp"
54 #include "utilities/debug.hpp"
55 #include "utilities/events.hpp"
56 #include "utilities/vmError.hpp"
57
58 // put OS-includes here
59 # include <sys/types.h>
60 # include <sys/mman.h>
61 # include <pthread.h>
62 # include <signal.h>
63 # include <errno.h>
64 # include <dlfcn.h>
65 # include <stdlib.h>
66 # include <stdio.h>
67 # include <unistd.h>
68 # include <sys/resource.h>
69 # include <pthread.h>
70 # include <sys/stat.h>
71 # include <sys/time.h>
72 # include <sys/utsname.h>
73 # include <sys/socket.h>
74 # include <sys/wait.h>
75 # include <pwd.h>
76 # include <poll.h>
77 # include <ucontext.h>
78 #ifndef AMD64
79 # include <fpu_control.h>
80 #endif
81
82 #ifdef AMD64
83 #define REG_SP REG_RSP
84 #define REG_PC REG_RIP
85 #define REG_FP REG_RBP
86 #define SPELL_REG_SP "rsp"
87 #define SPELL_REG_FP "rbp"
88 #else
89 #define REG_SP REG_UESP
90 #define REG_PC REG_EIP
91 #define REG_FP REG_EBP
92 #define SPELL_REG_SP "esp"
93 #define SPELL_REG_FP "ebp"
94 #endif // AMD64
95
96 address os::current_stack_pointer() {
97 #ifdef SPARC_WORKS
98 void *esp;
99 __asm__("mov %%" SPELL_REG_SP ", %0":"=r"(esp));
100 return (address) ((char*)esp + sizeof(long)*2);
101 #else
102 return (address)__builtin_frame_address(0);
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 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
115 return (address)uc->uc_mcontext.gregs[REG_PC];
116 }
117
118 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
119 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc;
120 }
121
122 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
123 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
124 }
125
126 intptr_t* os::Linux::ucontext_get_fp(const 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 // This method is also used for stack overflow signal handling.
136 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
137 const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
138
139 assert(thread != NULL, "just checking");
140 assert(ret_sp != NULL, "just checking");
141 assert(ret_fp != NULL, "just checking");
142
143 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
144 }
145
146 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
147 intptr_t** ret_sp, intptr_t** ret_fp) {
148
149 ExtendedPC epc;
150 const ucontext_t* uc = (const ucontext_t*)ucVoid;
151
152 if (uc != NULL) {
153 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
154 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
155 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
156 } else {
157 // construct empty ExtendedPC for return value checking
158 epc = ExtendedPC(NULL);
159 if (ret_sp) *ret_sp = (intptr_t *)NULL;
160 if (ret_fp) *ret_fp = (intptr_t *)NULL;
161 }
162
163 return epc;
164 }
165
166 frame os::fetch_frame_from_context(const void* ucVoid) {
167 intptr_t* sp;
168 intptr_t* fp;
169 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
170 return frame(sp, fp, epc.pc());
171 }
172
173 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
174 intptr_t* sp;
175 intptr_t* fp;
176 ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp);
177 return frame(sp, fp, epc.pc());
178 }
179
180 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
181 address pc = (address) os::Linux::ucontext_get_pc(uc);
182 if (Interpreter::contains(pc)) {
183 // interpreter performs stack banging after the fixed frame header has
184 // been generated while the compilers perform it before. To maintain
185 // semantic consistency between interpreted and compiled frames, the
186 // method returns the Java sender of the current frame.
187 *fr = os::fetch_frame_from_ucontext(thread, uc);
188 if (!fr->is_first_java_frame()) {
189 // get_frame_at_stack_banging_point() is only called when we
190 // have well defined stacks so java_sender() calls do not need
191 // to assert safe_for_sender() first.
192 *fr = fr->java_sender();
193 }
194 } else {
195 // more complex code with compiled code
196 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
197 CodeBlob* cb = CodeCache::find_blob(pc);
198 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
199 // Not sure where the pc points to, fallback to default
200 // stack overflow handling
201 return false;
202 } else {
203 // in compiled code, the stack banging is performed just after the return pc
204 // has been pushed on the stack
205 intptr_t* fp = os::Linux::ucontext_get_fp(uc);
206 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
207 *fr = frame(sp + 1, fp, (address)*sp);
208 if (!fr->is_java_frame()) {
209 assert(!fr->is_first_frame(), "Safety check");
210 // See java_sender() comment above.
211 *fr = fr->java_sender();
212 }
213 }
214 }
215 assert(fr->is_java_frame(), "Safety check");
216 return true;
217 }
218
219 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
220 // turned off by -fomit-frame-pointer,
221 frame os::get_sender_for_C_frame(frame* fr) {
222 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
223 }
224
225 intptr_t* _get_previous_fp() {
226 #ifdef SPARC_WORKS
227 intptr_t **ebp;
228 __asm__("mov %%" SPELL_REG_FP ", %0":"=r"(ebp));
229 #elif defined(__clang__)
230 intptr_t **ebp;
231 __asm__ __volatile__ ("mov %%" SPELL_REG_FP ", %0":"=r"(ebp):);
232 #else
233 register intptr_t **ebp __asm__ (SPELL_REG_FP);
234 #endif
235 // ebp is for this frame (_get_previous_fp). We want the ebp for the
236 // caller of os::current_frame*(), so go up two frames. However, for
237 // optimized builds, _get_previous_fp() will be inlined, so only go
238 // up 1 frame in that case.
239 #ifdef _NMT_NOINLINE_
240 return **(intptr_t***)ebp;
241 #else
242 return *ebp;
243 #endif
244 }
245
246
247 frame os::current_frame() {
248 intptr_t* fp = _get_previous_fp();
249 frame myframe((intptr_t*)os::current_stack_pointer(),
250 (intptr_t*)fp,
251 CAST_FROM_FN_PTR(address, os::current_frame));
252 if (os::is_first_C_frame(&myframe)) {
253 // stack is not walkable
254 return frame();
255 } else {
256 return os::get_sender_for_C_frame(&myframe);
257 }
258 }
259
260 // Utility functions
261
262 // From IA32 System Programming Guide
263 enum {
264 trap_page_fault = 0xE
265 };
266
267 extern "C" JNIEXPORT int
268 JVM_handle_linux_signal(int sig,
269 siginfo_t* info,
270 void* ucVoid,
271 int abort_if_unrecognized) {
272 ucontext_t* uc = (ucontext_t*) ucVoid;
273
274 Thread* t = Thread::current_or_null_safe();
275
276 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
277 // (no destructors can be run)
278 os::ThreadCrashProtection::check_crash_protection(sig, t);
279
280 SignalHandlerMark shm(t);
281
282 // Note: it's not uncommon that JNI code uses signal/sigset to install
283 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
284 // or have a SIGILL handler when detecting CPU type). When that happens,
285 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
286 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
287 // that do not require siginfo/ucontext first.
288
289 if (sig == SIGPIPE || sig == SIGXFSZ) {
290 // allow chained handler to go first
291 if (os::Linux::chained_handler(sig, info, ucVoid)) {
292 return true;
293 } else {
294 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
295 return true;
296 }
297 }
298
299 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
300 if ((sig == SIGSEGV || sig == SIGBUS) && info != NULL && info->si_addr == g_assert_poison) {
301 if (handle_assert_poison_fault(ucVoid, info->si_addr)) {
302 return 1;
303 }
304 }
305 #endif
306
307 JavaThread* thread = NULL;
308 VMThread* vmthread = NULL;
309 if (os::Linux::signal_handlers_are_installed) {
310 if (t != NULL ){
311 if(t->is_Java_thread()) {
312 thread = (JavaThread*)t;
313 }
314 else if(t->is_VM_thread()){
315 vmthread = (VMThread *)t;
316 }
317 }
318 }
319 /*
320 NOTE: does not seem to work on linux.
321 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
322 // can't decode this kind of signal
323 info = NULL;
324 } else {
325 assert(sig == info->si_signo, "bad siginfo");
326 }
327 */
328 // decide if this trap can be handled by a stub
329 address stub = NULL;
330
331 address pc = NULL;
332
333 //%note os_trap_1
334 if (info != NULL && uc != NULL && thread != NULL) {
335 pc = (address) os::Linux::ucontext_get_pc(uc);
336
337 if (StubRoutines::is_safefetch_fault(pc)) {
338 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
339 return 1;
340 }
341
342 #ifndef AMD64
343 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs
344 // This can happen in any running code (currently more frequently in
345 // interpreter code but has been seen in compiled code)
346 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) {
347 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due "
348 "to unstable signal handling in this distribution.");
349 }
350 #endif // AMD64
351
352 // Handle ALL stack overflow variations here
353 if (sig == SIGSEGV) {
354 address addr = (address) info->si_addr;
355
356 // check if fault address is within thread stack
357 if (thread->is_in_full_stack(addr)) {
358 // stack overflow
359 if (thread->in_stack_yellow_reserved_zone(addr)) {
360 if (thread->thread_state() == _thread_in_Java) {
361 if (thread->in_stack_reserved_zone(addr)) {
362 frame fr;
363 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
364 assert(fr.is_java_frame(), "Must be a Java frame");
365 frame activation =
366 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
367 if (activation.sp() != NULL) {
368 thread->disable_stack_reserved_zone();
369 if (activation.is_interpreted_frame()) {
370 thread->set_reserved_stack_activation((address)(
371 activation.fp() + frame::interpreter_frame_initial_sp_offset));
372 } else {
373 thread->set_reserved_stack_activation((address)activation.unextended_sp());
374 }
375 return 1;
376 }
377 }
378 }
379 // Throw a stack overflow exception. Guard pages will be reenabled
380 // while unwinding the stack.
381 thread->disable_stack_yellow_reserved_zone();
382 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
383 } else {
384 // Thread was in the vm or native code. Return and try to finish.
385 thread->disable_stack_yellow_reserved_zone();
386 return 1;
387 }
388 } else if (thread->in_stack_red_zone(addr)) {
389 // Fatal red zone violation. Disable the guard pages and fall through
390 // to handle_unexpected_exception way down below.
391 thread->disable_stack_red_zone();
392 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
393
394 // This is a likely cause, but hard to verify. Let's just print
395 // it as a hint.
396 tty->print_raw_cr("Please check if any of your loaded .so files has "
397 "enabled executable stack (see man page execstack(8))");
398 } else {
399 // Accessing stack address below sp may cause SEGV if current
400 // thread has MAP_GROWSDOWN stack. This should only happen when
401 // current thread was created by user code with MAP_GROWSDOWN flag
402 // and then attached to VM. See notes in os_linux.cpp.
403 if (thread->osthread()->expanding_stack() == 0) {
404 thread->osthread()->set_expanding_stack();
405 if (os::Linux::manually_expand_stack(thread, addr)) {
406 thread->osthread()->clear_expanding_stack();
407 return 1;
408 }
409 thread->osthread()->clear_expanding_stack();
410 } else {
411 fatal("recursive segv. expanding stack.");
412 }
413 }
414 }
415 }
416
417 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) {
418 // Verify that OS save/restore AVX registers.
419 stub = VM_Version::cpuinfo_cont_addr();
420 }
421
422 if (thread->thread_state() == _thread_in_Java) {
423 // Java thread running in Java code => find exception handler if any
424 // a fault inside compiled code, the interpreter, or a stub
425
426 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
427 stub = SharedRuntime::get_poll_stub(pc);
428 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
429 // BugId 4454115: A read from a MappedByteBuffer can fault
430 // here if the underlying file has been truncated.
431 // Do not crash the VM in such a case.
432 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
433 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
434 bool is_unsafe_arraycopy = thread->doing_unsafe_access() && UnsafeCopyMemory::contains_pc(pc);
435 if ((nm != NULL && nm->has_unsafe_access()) || is_unsafe_arraycopy) {
436 address next_pc = Assembler::locate_next_instruction(pc);
437 if (is_unsafe_arraycopy) {
438 next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
439 }
440 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
441 }
442 }
443 else
444
445 #ifdef AMD64
446 if (sig == SIGFPE &&
447 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
448 stub =
449 SharedRuntime::
450 continuation_for_implicit_exception(thread,
451 pc,
452 SharedRuntime::
453 IMPLICIT_DIVIDE_BY_ZERO);
454 #else
455 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
456 // HACK: si_code does not work on linux 2.2.12-20!!!
457 int op = pc[0];
458 if (op == 0xDB) {
459 // FIST
460 // TODO: The encoding of D2I in i486.ad can cause an exception
461 // prior to the fist instruction if there was an invalid operation
462 // pending. We want to dismiss that exception. From the win_32
463 // side it also seems that if it really was the fist causing
464 // the exception that we do the d2i by hand with different
465 // rounding. Seems kind of weird.
466 // NOTE: that we take the exception at the NEXT floating point instruction.
467 assert(pc[0] == 0xDB, "not a FIST opcode");
468 assert(pc[1] == 0x14, "not a FIST opcode");
469 assert(pc[2] == 0x24, "not a FIST opcode");
470 return true;
471 } else if (op == 0xF7) {
472 // IDIV
473 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
474 } else {
475 // TODO: handle more cases if we are using other x86 instructions
476 // that can generate SIGFPE signal on linux.
477 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
478 fatal("please update this code.");
479 }
480 #endif // AMD64
481 } else if (sig == SIGSEGV &&
482 MacroAssembler::uses_implicit_null_check(info->si_addr)) {
483 // Determination of interpreter/vtable stub/compiled code null exception
484 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
485 }
486 } else if ((thread->thread_state() == _thread_in_vm ||
487 thread->thread_state() == _thread_in_native) &&
488 (sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
489 thread->doing_unsafe_access())) {
490 address next_pc = Assembler::locate_next_instruction(pc);
491 if (UnsafeCopyMemory::contains_pc(pc)) {
492 next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
493 }
494 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
495 }
496
497 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
498 // and the heap gets shrunk before the field access.
499 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
500 address addr = JNI_FastGetField::find_slowcase_pc(pc);
501 if (addr != (address)-1) {
502 stub = addr;
503 }
504 }
505 }
506
507 #ifndef AMD64
508 // Execution protection violation
509 //
510 // This should be kept as the last step in the triage. We don't
511 // have a dedicated trap number for a no-execute fault, so be
512 // conservative and allow other handlers the first shot.
513 //
514 // Note: We don't test that info->si_code == SEGV_ACCERR here.
515 // this si_code is so generic that it is almost meaningless; and
516 // the si_code for this condition may change in the future.
517 // Furthermore, a false-positive should be harmless.
518 if (UnguardOnExecutionViolation > 0 &&
519 (sig == SIGSEGV || sig == SIGBUS) &&
520 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
521 int page_size = os::vm_page_size();
522 address addr = (address) info->si_addr;
523 address pc = os::Linux::ucontext_get_pc(uc);
524 // Make sure the pc and the faulting address are sane.
525 //
526 // If an instruction spans a page boundary, and the page containing
527 // the beginning of the instruction is executable but the following
528 // page is not, the pc and the faulting address might be slightly
529 // different - we still want to unguard the 2nd page in this case.
530 //
531 // 15 bytes seems to be a (very) safe value for max instruction size.
532 bool pc_is_near_addr =
533 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
534 bool instr_spans_page_boundary =
535 (align_down((intptr_t) pc ^ (intptr_t) addr,
536 (intptr_t) page_size) > 0);
537
538 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
539 static volatile address last_addr =
540 (address) os::non_memory_address_word();
541
542 // In conservative mode, don't unguard unless the address is in the VM
543 if (addr != last_addr &&
544 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
545
546 // Set memory to RWX and retry
547 address page_start = align_down(addr, page_size);
548 bool res = os::protect_memory((char*) page_start, page_size,
549 os::MEM_PROT_RWX);
550
551 log_debug(os)("Execution protection violation "
552 "at " INTPTR_FORMAT
553 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
554 p2i(page_start), (res ? "success" : "failed"), errno);
555 stub = pc;
556
557 // Set last_addr so if we fault again at the same address, we don't end
558 // up in an endless loop.
559 //
560 // There are two potential complications here. Two threads trapping at
561 // the same address at the same time could cause one of the threads to
562 // think it already unguarded, and abort the VM. Likely very rare.
563 //
564 // The other race involves two threads alternately trapping at
565 // different addresses and failing to unguard the page, resulting in
566 // an endless loop. This condition is probably even more unlikely than
567 // the first.
568 //
569 // Although both cases could be avoided by using locks or thread local
570 // last_addr, these solutions are unnecessary complication: this
571 // handler is a best-effort safety net, not a complete solution. It is
572 // disabled by default and should only be used as a workaround in case
573 // we missed any no-execute-unsafe VM code.
574
575 last_addr = addr;
576 }
577 }
578 }
579 #endif // !AMD64
580
581 if (stub != NULL) {
582 // save all thread context in case we need to restore it
583 if (thread != NULL) thread->set_saved_exception_pc(pc);
584
585 os::Linux::ucontext_set_pc(uc, stub);
586 return true;
587 }
588
589 // signal-chaining
590 if (os::Linux::chained_handler(sig, info, ucVoid)) {
591 return true;
592 }
593
594 if (!abort_if_unrecognized) {
595 // caller wants another chance, so give it to him
596 return false;
597 }
598
599 if (pc == NULL && uc != NULL) {
600 pc = os::Linux::ucontext_get_pc(uc);
601 }
602
603 // unmask current signal
604 sigset_t newset;
605 sigemptyset(&newset);
606 sigaddset(&newset, sig);
607 sigprocmask(SIG_UNBLOCK, &newset, NULL);
608
609 VMError::report_and_die(t, sig, pc, info, ucVoid);
610
611 ShouldNotReachHere();
612 return true; // Mute compiler
613 }
614
615 void os::Linux::init_thread_fpu_state(void) {
616 #ifndef AMD64
617 // set fpu to 53 bit precision
618 set_fpu_control_word(0x27f);
619 #endif // !AMD64
620 }
621
622 int os::Linux::get_fpu_control_word(void) {
623 #ifdef AMD64
624 return 0;
625 #else
626 int fpu_control;
627 _FPU_GETCW(fpu_control);
628 return fpu_control & 0xffff;
629 #endif // AMD64
630 }
631
632 void os::Linux::set_fpu_control_word(int fpu_control) {
633 #ifndef AMD64
634 _FPU_SETCW(fpu_control);
635 #endif // !AMD64
636 }
637
638 // Check that the linux kernel version is 2.4 or higher since earlier
639 // versions do not support SSE without patches.
640 bool os::supports_sse() {
641 #ifdef AMD64
642 return true;
643 #else
644 struct utsname uts;
645 if( uname(&uts) != 0 ) return false; // uname fails?
646 char *minor_string;
647 int major = strtol(uts.release,&minor_string,10);
648 int minor = strtol(minor_string+1,NULL,10);
649 bool result = (major > 2 || (major==2 && minor >= 4));
650 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2",
651 major,minor, result ? "DOES" : "does NOT");
652 return result;
653 #endif // AMD64
654 }
655
656 bool os::is_allocatable(size_t bytes) {
657 #ifdef AMD64
658 // unused on amd64?
659 return true;
660 #else
661
662 if (bytes < 2 * G) {
663 return true;
664 }
665
666 char* addr = reserve_memory(bytes, NULL);
667
668 if (addr != NULL) {
669 release_memory(addr, bytes);
670 }
671
672 return addr != NULL;
673 #endif // AMD64
674 }
675
676 ////////////////////////////////////////////////////////////////////////////////
677 // thread stack
678
679 // Minimum usable stack sizes required to get to user code. Space for
680 // HotSpot guard pages is added later.
681 size_t os::Posix::_compiler_thread_min_stack_allowed = 48 * K;
682 size_t os::Posix::_java_thread_min_stack_allowed = 40 * K;
683 #ifdef _LP64
684 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
685 #else
686 size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
687 #endif // _LP64
688
689 // return default stack size for thr_type
690 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
691 // default stack size (compiler thread needs larger stack)
692 #ifdef AMD64
693 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
694 #else
695 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
696 #endif // AMD64
697 return s;
698 }
699
700 /////////////////////////////////////////////////////////////////////////////
701 // helper functions for fatal error handler
702
703 void os::print_context(outputStream *st, const void *context) {
704 if (context == NULL) return;
705
706 const ucontext_t *uc = (const ucontext_t*)context;
707 st->print_cr("Registers:");
708 #ifdef AMD64
709 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]);
710 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]);
711 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]);
712 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]);
713 st->cr();
714 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]);
715 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]);
716 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]);
717 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]);
718 st->cr();
719 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]);
720 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]);
721 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]);
722 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]);
723 st->cr();
724 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]);
725 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]);
726 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]);
727 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]);
728 st->cr();
729 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]);
730 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]);
731 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]);
732 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]);
733 st->cr();
734 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]);
735 #else
736 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
737 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
738 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
739 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
740 st->cr();
741 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
742 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
743 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
744 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
745 st->cr();
746 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
747 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
748 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2);
749 #endif // AMD64
750 st->cr();
751 st->cr();
752
753 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
754 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
755 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t));
756 st->cr();
757
758 // Note: it may be unsafe to inspect memory near pc. For example, pc may
759 // point to garbage if entry point in an nmethod is corrupted. Leave
760 // this at the end, and hope for the best.
761 address pc = os::Linux::ucontext_get_pc(uc);
762 print_instructions(st, pc, sizeof(char));
763 st->cr();
764 }
765
766 void os::print_register_info(outputStream *st, const void *context) {
767 if (context == NULL) return;
768
769 const ucontext_t *uc = (const ucontext_t*)context;
770
771 st->print_cr("Register to memory mapping:");
772 st->cr();
773
774 // this is horrendously verbose but the layout of the registers in the
775 // context does not match how we defined our abstract Register set, so
776 // we can't just iterate through the gregs area
777
778 // this is only for the "general purpose" registers
779
780 #ifdef AMD64
781 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
782 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
783 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
784 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
785 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
786 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
787 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
788 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
789 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
790 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
791 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
792 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
793 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
794 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
795 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
796 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
797 #else
798 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
799 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
800 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
801 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
802 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
803 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
804 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
805 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
806 #endif // AMD64
807
808 st->cr();
809 }
810
811 void os::setup_fpu() {
812 #ifndef AMD64
813 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
814 __asm__ volatile ( "fldcw (%0)" :
815 : "r" (fpu_cntrl) : "memory");
816 #endif // !AMD64
817 }
818
819 #ifndef PRODUCT
820 void os::verify_stack_alignment() {
821 #ifdef AMD64
822 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
823 #endif
824 }
825 #endif
826
827
828 /*
829 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit
830 * updates (JDK-8023956).
831 */
832 void os::workaround_expand_exec_shield_cs_limit() {
833 #if defined(IA32)
834 assert(Linux::initial_thread_stack_bottom() != NULL, "sanity");
835 size_t page_size = os::vm_page_size();
836
837 /*
838 * JDK-8197429
839 *
840 * Expand the stack mapping to the end of the initial stack before
841 * attempting to install the codebuf. This is needed because newer
842 * Linux kernels impose a distance of a megabyte between stack
843 * memory and other memory regions. If we try to install the
844 * codebuf before expanding the stack the installation will appear
845 * to succeed but we'll get a segfault later if we expand the stack
846 * in Java code.
847 *
848 */
849 if (os::is_primordial_thread()) {
850 address limit = Linux::initial_thread_stack_bottom();
851 if (! DisablePrimordialThreadGuardPages) {
852 limit += JavaThread::stack_red_zone_size() +
853 JavaThread::stack_yellow_zone_size();
854 }
855 os::Linux::expand_stack_to(limit);
856 }
857
858 /*
859 * Take the highest VA the OS will give us and exec
860 *
861 * Although using -(pagesz) as mmap hint works on newer kernel as you would
862 * think, older variants affected by this work-around don't (search forward only).
863 *
864 * On the affected distributions, we understand the memory layout to be:
865 *
866 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT.
867 *
868 * A few pages south main stack will do it.
869 *
870 * If we are embedded in an app other than launcher (initial != main stack),
871 * we don't have much control or understanding of the address space, just let it slide.
872 */
873 char* hint = (char*)(Linux::initial_thread_stack_bottom() -
874 (JavaThread::stack_guard_zone_size() + page_size));
875 char* codebuf = os::attempt_reserve_memory_at(page_size, hint);
876
877 if (codebuf == NULL) {
878 // JDK-8197429: There may be a stack gap of one megabyte between
879 // the limit of the stack and the nearest memory region: this is a
880 // Linux kernel workaround for CVE-2017-1000364. If we failed to
881 // map our codebuf, try again at an address one megabyte lower.
882 hint -= 1 * M;
883 codebuf = os::attempt_reserve_memory_at(page_size, hint);
884 }
885
886 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) {
887 return; // No matter, we tried, best effort.
888 }
889
890 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal);
891
892 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf);
893
894 // Some code to exec: the 'ret' instruction
895 codebuf[0] = 0xC3;
896
897 // Call the code in the codebuf
898 __asm__ volatile("call *%0" : : "r"(codebuf));
899
900 // keep the page mapped so CS limit isn't reduced.
901 #endif
902 }
903
904 int os::extra_bang_size_in_bytes() {
905 // JDK-8050147 requires the full cache line bang for x86.
906 return VM_Version::L1_line_size();
907 }