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/frame.inline.hpp"
42 #include "runtime/interfaceSupport.inline.hpp"
43 #include "runtime/java.hpp"
44 #include "runtime/javaCalls.hpp"
45 #include "runtime/mutexLocker.hpp"
46 #include "runtime/osThread.hpp"
47 #include "runtime/safepointMechanism.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 return (address)__builtin_frame_address(0);
98 }
99
100 char* os::non_memory_address_word() {
101 // Must never look like an address returned by reserve_memory,
102 // even in its subfields (as defined by the CPU immediate fields,
103 // if the CPU splits constants across multiple instructions).
104
105 return (char*) -1;
106 }
107
108 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
109 return (address)uc->uc_mcontext.gregs[REG_PC];
110 }
111
112 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
113 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc;
114 }
115
116 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
117 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
118 }
119
120 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
121 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
122 }
123
124 address os::fetch_frame_from_context(const void* ucVoid,
125 intptr_t** ret_sp, intptr_t** ret_fp) {
126
127 address epc;
128 const ucontext_t* uc = (const ucontext_t*)ucVoid;
129
130 if (uc != NULL) {
131 epc = os::Linux::ucontext_get_pc(uc);
132 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
133 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
134 } else {
135 epc = NULL;
136 if (ret_sp) *ret_sp = (intptr_t *)NULL;
137 if (ret_fp) *ret_fp = (intptr_t *)NULL;
138 }
139
140 return epc;
141 }
142
143 frame os::fetch_frame_from_context(const void* ucVoid) {
144 intptr_t* sp;
145 intptr_t* fp;
146 address epc = fetch_frame_from_context(ucVoid, &sp, &fp);
147 return frame(sp, fp, epc);
148 }
149
150 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
151 address pc = (address) os::Linux::ucontext_get_pc(uc);
152 if (Interpreter::contains(pc)) {
153 // interpreter performs stack banging after the fixed frame header has
154 // been generated while the compilers perform it before. To maintain
155 // semantic consistency between interpreted and compiled frames, the
156 // method returns the Java sender of the current frame.
157 *fr = os::fetch_frame_from_context(uc);
158 if (!fr->is_first_java_frame()) {
159 // get_frame_at_stack_banging_point() is only called when we
160 // have well defined stacks so java_sender() calls do not need
161 // to assert safe_for_sender() first.
162 *fr = fr->java_sender();
163 }
164 } else {
165 // more complex code with compiled code
166 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
167 CodeBlob* cb = CodeCache::find_blob(pc);
168 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
169 // Not sure where the pc points to, fallback to default
170 // stack overflow handling
171 return false;
172 } else {
173 // in compiled code, the stack banging is performed just after the return pc
174 // has been pushed on the stack
175 intptr_t* fp = os::Linux::ucontext_get_fp(uc);
176 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
177 *fr = frame(sp + 1, fp, (address)*sp);
178 if (!fr->is_java_frame()) {
179 assert(!fr->is_first_frame(), "Safety check");
180 // See java_sender() comment above.
181 *fr = fr->java_sender();
182 }
183 }
184 }
185 assert(fr->is_java_frame(), "Safety check");
186 return true;
187 }
188
189 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
190 // turned off by -fomit-frame-pointer,
191 frame os::get_sender_for_C_frame(frame* fr) {
192 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
193 }
194
195 intptr_t* _get_previous_fp() {
196 #if defined(__clang__)
197 intptr_t **ebp;
198 __asm__ __volatile__ ("mov %%" SPELL_REG_FP ", %0":"=r"(ebp):);
199 #else
200 register intptr_t **ebp __asm__ (SPELL_REG_FP);
201 #endif
202 // ebp is for this frame (_get_previous_fp). We want the ebp for the
203 // caller of os::current_frame*(), so go up two frames. However, for
204 // optimized builds, _get_previous_fp() will be inlined, so only go
205 // up 1 frame in that case.
206 #ifdef _NMT_NOINLINE_
207 return **(intptr_t***)ebp;
208 #else
209 return *ebp;
210 #endif
211 }
212
213
214 frame os::current_frame() {
215 intptr_t* fp = _get_previous_fp();
216 frame myframe((intptr_t*)os::current_stack_pointer(),
217 (intptr_t*)fp,
218 CAST_FROM_FN_PTR(address, os::current_frame));
219 if (os::is_first_C_frame(&myframe)) {
220 // stack is not walkable
221 return frame();
222 } else {
223 return os::get_sender_for_C_frame(&myframe);
224 }
225 }
226
227 // Utility functions
228
229 // From IA32 System Programming Guide
230 enum {
231 trap_page_fault = 0xE
232 };
233
234 extern "C" JNIEXPORT int
235 JVM_handle_linux_signal(int sig,
236 siginfo_t* info,
237 void* ucVoid,
238 int abort_if_unrecognized) {
239 ucontext_t* uc = (ucontext_t*) ucVoid;
240
241 Thread* t = Thread::current_or_null_safe();
242
243 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
244 // (no destructors can be run)
245 os::ThreadCrashProtection::check_crash_protection(sig, t);
246
247 SignalHandlerMark shm(t);
248
249 // Note: it's not uncommon that JNI code uses signal/sigset to install
250 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
251 // or have a SIGILL handler when detecting CPU type). When that happens,
252 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
253 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
254 // that do not require siginfo/ucontext first.
255
256 if (sig == SIGPIPE || sig == SIGXFSZ) {
257 // allow chained handler to go first
258 if (os::Linux::chained_handler(sig, info, ucVoid)) {
259 return true;
260 } else {
261 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
262 return true;
263 }
264 }
265
266 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
267 if ((sig == SIGSEGV || sig == SIGBUS) && info != NULL && info->si_addr == g_assert_poison) {
268 if (handle_assert_poison_fault(ucVoid, info->si_addr)) {
269 return 1;
270 }
271 }
272 #endif
273
274 JavaThread* thread = NULL;
275 VMThread* vmthread = NULL;
276 if (os::Linux::signal_handlers_are_installed) {
277 if (t != NULL ){
278 if(t->is_Java_thread()) {
279 thread = (JavaThread*)t;
280 }
281 else if(t->is_VM_thread()){
282 vmthread = (VMThread *)t;
283 }
284 }
285 }
286 /*
287 NOTE: does not seem to work on linux.
288 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
289 // can't decode this kind of signal
290 info = NULL;
291 } else {
292 assert(sig == info->si_signo, "bad siginfo");
293 }
294 */
295 // decide if this trap can be handled by a stub
296 address stub = NULL;
297
298 address pc = NULL;
299
300 //%note os_trap_1
301 if (info != NULL && uc != NULL && thread != NULL) {
302 pc = (address) os::Linux::ucontext_get_pc(uc);
303
304 if (StubRoutines::is_safefetch_fault(pc)) {
305 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
306 return 1;
307 }
308
309 #ifndef AMD64
310 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs
311 // This can happen in any running code (currently more frequently in
312 // interpreter code but has been seen in compiled code)
313 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) {
314 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due "
315 "to unstable signal handling in this distribution.");
316 }
317 #endif // AMD64
318
319 // Handle ALL stack overflow variations here
320 if (sig == SIGSEGV) {
321 address addr = (address) info->si_addr;
322
323 // check if fault address is within thread stack
324 if (thread->is_in_full_stack(addr)) {
325 // stack overflow
326 if (thread->in_stack_yellow_reserved_zone(addr)) {
327 if (thread->thread_state() == _thread_in_Java) {
328 if (thread->in_stack_reserved_zone(addr)) {
329 frame fr;
330 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
331 assert(fr.is_java_frame(), "Must be a Java frame");
332 frame activation =
333 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
334 if (activation.sp() != NULL) {
335 thread->disable_stack_reserved_zone();
336 if (activation.is_interpreted_frame()) {
337 thread->set_reserved_stack_activation((address)(
338 activation.fp() + frame::interpreter_frame_initial_sp_offset));
339 } else {
340 thread->set_reserved_stack_activation((address)activation.unextended_sp());
341 }
342 return 1;
343 }
344 }
345 }
346 // Throw a stack overflow exception. Guard pages will be reenabled
347 // while unwinding the stack.
348 thread->disable_stack_yellow_reserved_zone();
349 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
350 } else {
351 // Thread was in the vm or native code. Return and try to finish.
352 thread->disable_stack_yellow_reserved_zone();
353 return 1;
354 }
355 } else if (thread->in_stack_red_zone(addr)) {
356 // Fatal red zone violation. Disable the guard pages and fall through
357 // to handle_unexpected_exception way down below.
358 thread->disable_stack_red_zone();
359 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
360
361 // This is a likely cause, but hard to verify. Let's just print
362 // it as a hint.
363 tty->print_raw_cr("Please check if any of your loaded .so files has "
364 "enabled executable stack (see man page execstack(8))");
365 } else {
366 // Accessing stack address below sp may cause SEGV if current
367 // thread has MAP_GROWSDOWN stack. This should only happen when
368 // current thread was created by user code with MAP_GROWSDOWN flag
369 // and then attached to VM. See notes in os_linux.cpp.
370 if (thread->osthread()->expanding_stack() == 0) {
371 thread->osthread()->set_expanding_stack();
372 if (os::Linux::manually_expand_stack(thread, addr)) {
373 thread->osthread()->clear_expanding_stack();
374 return 1;
375 }
376 thread->osthread()->clear_expanding_stack();
377 } else {
378 fatal("recursive segv. expanding stack.");
379 }
380 }
381 }
382 }
383
384 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) {
385 // Verify that OS save/restore AVX registers.
386 stub = VM_Version::cpuinfo_cont_addr();
387 }
388
389 if (thread->thread_state() == _thread_in_Java) {
390 // Java thread running in Java code => find exception handler if any
391 // a fault inside compiled code, the interpreter, or a stub
392
393 if (sig == SIGSEGV && SafepointMechanism::is_poll_address((address)info->si_addr)) {
394 stub = SharedRuntime::get_poll_stub(pc);
395 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
396 // BugId 4454115: A read from a MappedByteBuffer can fault
397 // here if the underlying file has been truncated.
398 // Do not crash the VM in such a case.
399 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
400 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
401 bool is_unsafe_arraycopy = thread->doing_unsafe_access() && UnsafeCopyMemory::contains_pc(pc);
402 if ((nm != NULL && nm->has_unsafe_access()) || is_unsafe_arraycopy) {
403 address next_pc = Assembler::locate_next_instruction(pc);
404 if (is_unsafe_arraycopy) {
405 next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
406 }
407 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
408 }
409 }
410 else
411
412 #ifdef AMD64
413 if (sig == SIGFPE &&
414 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
415 stub =
416 SharedRuntime::
417 continuation_for_implicit_exception(thread,
418 pc,
419 SharedRuntime::
420 IMPLICIT_DIVIDE_BY_ZERO);
421 #else
422 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
423 // HACK: si_code does not work on linux 2.2.12-20!!!
424 int op = pc[0];
425 if (op == 0xDB) {
426 // FIST
427 // TODO: The encoding of D2I in i486.ad can cause an exception
428 // prior to the fist instruction if there was an invalid operation
429 // pending. We want to dismiss that exception. From the win_32
430 // side it also seems that if it really was the fist causing
431 // the exception that we do the d2i by hand with different
432 // rounding. Seems kind of weird.
433 // NOTE: that we take the exception at the NEXT floating point instruction.
434 assert(pc[0] == 0xDB, "not a FIST opcode");
435 assert(pc[1] == 0x14, "not a FIST opcode");
436 assert(pc[2] == 0x24, "not a FIST opcode");
437 return true;
438 } else if (op == 0xF7) {
439 // IDIV
440 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
441 } else {
442 // TODO: handle more cases if we are using other x86 instructions
443 // that can generate SIGFPE signal on linux.
444 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
445 fatal("please update this code.");
446 }
447 #endif // AMD64
448 } else if (sig == SIGSEGV &&
449 MacroAssembler::uses_implicit_null_check(info->si_addr)) {
450 // Determination of interpreter/vtable stub/compiled code null exception
451 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
452 }
453 } else if ((thread->thread_state() == _thread_in_vm ||
454 thread->thread_state() == _thread_in_native) &&
455 (sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
456 thread->doing_unsafe_access())) {
457 address next_pc = Assembler::locate_next_instruction(pc);
458 if (UnsafeCopyMemory::contains_pc(pc)) {
459 next_pc = UnsafeCopyMemory::page_error_continue_pc(pc);
460 }
461 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
462 }
463
464 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
465 // and the heap gets shrunk before the field access.
466 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
467 address addr = JNI_FastGetField::find_slowcase_pc(pc);
468 if (addr != (address)-1) {
469 stub = addr;
470 }
471 }
472 }
473
474 #ifndef AMD64
475 // Execution protection violation
476 //
477 // This should be kept as the last step in the triage. We don't
478 // have a dedicated trap number for a no-execute fault, so be
479 // conservative and allow other handlers the first shot.
480 //
481 // Note: We don't test that info->si_code == SEGV_ACCERR here.
482 // this si_code is so generic that it is almost meaningless; and
483 // the si_code for this condition may change in the future.
484 // Furthermore, a false-positive should be harmless.
485 if (UnguardOnExecutionViolation > 0 &&
486 (sig == SIGSEGV || sig == SIGBUS) &&
487 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
488 int page_size = os::vm_page_size();
489 address addr = (address) info->si_addr;
490 address pc = os::Linux::ucontext_get_pc(uc);
491 // Make sure the pc and the faulting address are sane.
492 //
493 // If an instruction spans a page boundary, and the page containing
494 // the beginning of the instruction is executable but the following
495 // page is not, the pc and the faulting address might be slightly
496 // different - we still want to unguard the 2nd page in this case.
497 //
498 // 15 bytes seems to be a (very) safe value for max instruction size.
499 bool pc_is_near_addr =
500 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
501 bool instr_spans_page_boundary =
502 (align_down((intptr_t) pc ^ (intptr_t) addr,
503 (intptr_t) page_size) > 0);
504
505 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
506 static volatile address last_addr =
507 (address) os::non_memory_address_word();
508
509 // In conservative mode, don't unguard unless the address is in the VM
510 if (addr != last_addr &&
511 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
512
513 // Set memory to RWX and retry
514 address page_start = align_down(addr, page_size);
515 bool res = os::protect_memory((char*) page_start, page_size,
516 os::MEM_PROT_RWX);
517
518 log_debug(os)("Execution protection violation "
519 "at " INTPTR_FORMAT
520 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
521 p2i(page_start), (res ? "success" : "failed"), errno);
522 stub = pc;
523
524 // Set last_addr so if we fault again at the same address, we don't end
525 // up in an endless loop.
526 //
527 // There are two potential complications here. Two threads trapping at
528 // the same address at the same time could cause one of the threads to
529 // think it already unguarded, and abort the VM. Likely very rare.
530 //
531 // The other race involves two threads alternately trapping at
532 // different addresses and failing to unguard the page, resulting in
533 // an endless loop. This condition is probably even more unlikely than
534 // the first.
535 //
536 // Although both cases could be avoided by using locks or thread local
537 // last_addr, these solutions are unnecessary complication: this
538 // handler is a best-effort safety net, not a complete solution. It is
539 // disabled by default and should only be used as a workaround in case
540 // we missed any no-execute-unsafe VM code.
541
542 last_addr = addr;
543 }
544 }
545 }
546 #endif // !AMD64
547
548 if (stub != NULL) {
549 // save all thread context in case we need to restore it
550 if (thread != NULL) thread->set_saved_exception_pc(pc);
551
552 os::Linux::ucontext_set_pc(uc, stub);
553 return true;
554 }
555
556 // signal-chaining
557 if (os::Linux::chained_handler(sig, info, ucVoid)) {
558 return true;
559 }
560
561 if (!abort_if_unrecognized) {
562 // caller wants another chance, so give it to him
563 return false;
564 }
565
566 if (pc == NULL && uc != NULL) {
567 pc = os::Linux::ucontext_get_pc(uc);
568 }
569
570 // unmask current signal
571 sigset_t newset;
572 sigemptyset(&newset);
573 sigaddset(&newset, sig);
574 sigprocmask(SIG_UNBLOCK, &newset, NULL);
575
576 VMError::report_and_die(t, sig, pc, info, ucVoid);
577
578 ShouldNotReachHere();
579 return true; // Mute compiler
580 }
581
582 void os::Linux::init_thread_fpu_state(void) {
583 #ifndef AMD64
584 // set fpu to 53 bit precision
585 set_fpu_control_word(0x27f);
586 #endif // !AMD64
587 }
588
589 int os::Linux::get_fpu_control_word(void) {
590 #ifdef AMD64
591 return 0;
592 #else
593 int fpu_control;
594 _FPU_GETCW(fpu_control);
595 return fpu_control & 0xffff;
596 #endif // AMD64
597 }
598
599 void os::Linux::set_fpu_control_word(int fpu_control) {
600 #ifndef AMD64
601 _FPU_SETCW(fpu_control);
602 #endif // !AMD64
603 }
604
605 // Check that the linux kernel version is 2.4 or higher since earlier
606 // versions do not support SSE without patches.
607 bool os::supports_sse() {
608 #ifdef AMD64
609 return true;
610 #else
611 struct utsname uts;
612 if( uname(&uts) != 0 ) return false; // uname fails?
613 char *minor_string;
614 int major = strtol(uts.release,&minor_string,10);
615 int minor = strtol(minor_string+1,NULL,10);
616 bool result = (major > 2 || (major==2 && minor >= 4));
617 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2",
618 major,minor, result ? "DOES" : "does NOT");
619 return result;
620 #endif // AMD64
621 }
622
623 juint os::cpu_microcode_revision() {
624 juint result = 0;
625 char data[2048] = {0}; // lines should fit in 2K buf
626 size_t len = sizeof(data);
627 FILE *fp = fopen("/proc/cpuinfo", "r");
628 if (fp) {
629 while (!feof(fp)) {
630 if (fgets(data, len, fp)) {
631 if (strstr(data, "microcode") != NULL) {
632 char* rev = strchr(data, ':');
633 if (rev != NULL) sscanf(rev + 1, "%x", &result);
634 break;
635 }
636 }
637 }
638 fclose(fp);
639 }
640 return result;
641 }
642
643 bool os::is_allocatable(size_t bytes) {
644 #ifdef AMD64
645 // unused on amd64?
646 return true;
647 #else
648
649 if (bytes < 2 * G) {
650 return true;
651 }
652
653 char* addr = reserve_memory(bytes, NULL);
654
655 if (addr != NULL) {
656 release_memory(addr, bytes);
657 }
658
659 return addr != NULL;
660 #endif // AMD64
661 }
662
663 ////////////////////////////////////////////////////////////////////////////////
664 // thread stack
665
666 // Minimum usable stack sizes required to get to user code. Space for
667 // HotSpot guard pages is added later.
668 size_t os::Posix::_compiler_thread_min_stack_allowed = 48 * K;
669 size_t os::Posix::_java_thread_min_stack_allowed = 40 * K;
670 #ifdef _LP64
671 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
672 #else
673 size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
674 #endif // _LP64
675
676 // return default stack size for thr_type
677 size_t os::Posix::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 /////////////////////////////////////////////////////////////////////////////
688 // helper functions for fatal error handler
689
690 void os::print_context(outputStream *st, const void *context) {
691 if (context == NULL) return;
692
693 const ucontext_t *uc = (const ucontext_t*)context;
694 st->print_cr("Registers:");
695 #ifdef AMD64
696 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]);
697 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]);
698 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]);
699 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]);
700 st->cr();
701 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]);
702 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]);
703 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]);
704 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]);
705 st->cr();
706 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]);
707 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]);
708 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]);
709 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]);
710 st->cr();
711 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]);
712 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]);
713 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]);
714 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]);
715 st->cr();
716 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]);
717 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]);
718 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]);
719 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]);
720 st->cr();
721 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]);
722 #else
723 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
724 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
725 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
726 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
727 st->cr();
728 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
729 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
730 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
731 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
732 st->cr();
733 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
734 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
735 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2);
736 #endif // AMD64
737 st->cr();
738 st->cr();
739
740 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
741 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
742 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t));
743 st->cr();
744
745 // Note: it may be unsafe to inspect memory near pc. For example, pc may
746 // point to garbage if entry point in an nmethod is corrupted. Leave
747 // this at the end, and hope for the best.
748 address pc = os::Linux::ucontext_get_pc(uc);
749 print_instructions(st, pc, sizeof(char));
750 st->cr();
751 }
752
753 void os::print_register_info(outputStream *st, const void *context) {
754 if (context == NULL) return;
755
756 const ucontext_t *uc = (const ucontext_t*)context;
757
758 st->print_cr("Register to memory mapping:");
759 st->cr();
760
761 // this is horrendously verbose but the layout of the registers in the
762 // context does not match how we defined our abstract Register set, so
763 // we can't just iterate through the gregs area
764
765 // this is only for the "general purpose" registers
766
767 #ifdef AMD64
768 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
769 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
770 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
771 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
772 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
773 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
774 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
775 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
776 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
777 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
778 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
779 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
780 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
781 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
782 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
783 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
784 #else
785 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
786 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
787 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
788 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
789 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
790 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
791 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
792 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
793 #endif // AMD64
794
795 st->cr();
796 }
797
798 void os::setup_fpu() {
799 #ifndef AMD64
800 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
801 __asm__ volatile ( "fldcw (%0)" :
802 : "r" (fpu_cntrl) : "memory");
803 #endif // !AMD64
804 }
805
806 #ifndef PRODUCT
807 void os::verify_stack_alignment() {
808 #ifdef AMD64
809 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
810 #endif
811 }
812 #endif
813
814
815 /*
816 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit
817 * updates (JDK-8023956).
818 */
819 void os::workaround_expand_exec_shield_cs_limit() {
820 #if defined(IA32)
821 assert(Linux::initial_thread_stack_bottom() != NULL, "sanity");
822 size_t page_size = os::vm_page_size();
823
824 /*
825 * JDK-8197429
826 *
827 * Expand the stack mapping to the end of the initial stack before
828 * attempting to install the codebuf. This is needed because newer
829 * Linux kernels impose a distance of a megabyte between stack
830 * memory and other memory regions. If we try to install the
831 * codebuf before expanding the stack the installation will appear
832 * to succeed but we'll get a segfault later if we expand the stack
833 * in Java code.
834 *
835 */
836 if (os::is_primordial_thread()) {
837 address limit = Linux::initial_thread_stack_bottom();
838 if (! DisablePrimordialThreadGuardPages) {
839 limit += JavaThread::stack_red_zone_size() +
840 JavaThread::stack_yellow_zone_size();
841 }
842 os::Linux::expand_stack_to(limit);
843 }
844
845 /*
846 * Take the highest VA the OS will give us and exec
847 *
848 * Although using -(pagesz) as mmap hint works on newer kernel as you would
849 * think, older variants affected by this work-around don't (search forward only).
850 *
851 * On the affected distributions, we understand the memory layout to be:
852 *
853 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT.
854 *
855 * A few pages south main stack will do it.
856 *
857 * If we are embedded in an app other than launcher (initial != main stack),
858 * we don't have much control or understanding of the address space, just let it slide.
859 */
860 char* hint = (char*)(Linux::initial_thread_stack_bottom() -
861 (JavaThread::stack_guard_zone_size() + page_size));
862 char* codebuf = os::attempt_reserve_memory_at(page_size, hint);
863
864 if (codebuf == NULL) {
865 // JDK-8197429: There may be a stack gap of one megabyte between
866 // the limit of the stack and the nearest memory region: this is a
867 // Linux kernel workaround for CVE-2017-1000364. If we failed to
868 // map our codebuf, try again at an address one megabyte lower.
869 hint -= 1 * M;
870 codebuf = os::attempt_reserve_memory_at(page_size, hint);
871 }
872
873 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) {
874 return; // No matter, we tried, best effort.
875 }
876
877 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal);
878
879 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf);
880
881 // Some code to exec: the 'ret' instruction
882 codebuf[0] = 0xC3;
883
884 // Call the code in the codebuf
885 __asm__ volatile("call *%0" : : "r"(codebuf));
886
887 // keep the page mapped so CS limit isn't reduced.
888 #endif
889 }
890
891 int os::extra_bang_size_in_bytes() {
892 // JDK-8050147 requires the full cache line bang for x86.
893 return VM_Version::L1_line_size();
894 }
--- EOF ---