1 /*
2 * Copyright (c) 1999, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2014, Red Hat Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 // no precompiled headers
27 #include "asm/macroAssembler.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/codeCache.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "code/nativeInst.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "jvm.h"
34 #include "memory/allocation.inline.hpp"
35 #include "os_linux.hpp"
36 #include "os_posix.hpp"
37 #include "prims/jniFastGetField.hpp"
38 #include "prims/jvm_misc.hpp"
39 #include "runtime/arguments.hpp"
40 #include "runtime/frame.inline.hpp"
41 #include "runtime/interfaceSupport.inline.hpp"
42 #include "runtime/java.hpp"
43 #include "runtime/javaCalls.hpp"
44 #include "runtime/mutexLocker.hpp"
45 #include "runtime/osThread.hpp"
46 #include "runtime/safepointMechanism.hpp"
47 #include "runtime/sharedRuntime.hpp"
48 #include "runtime/stubRoutines.hpp"
49 #include "runtime/javaThread.hpp"
50 #include "runtime/timer.hpp"
51 #include "signals_posix.hpp"
52 #include "utilities/debug.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
77 #define REG_FP 29
78 #define REG_LR 30
79
80 NOINLINE address os::current_stack_pointer() {
81 return (address)__builtin_frame_address(0);
82 }
83
84 char* os::non_memory_address_word() {
85 // Must never look like an address returned by reserve_memory,
86 // even in its subfields (as defined by the CPU immediate fields,
87 // if the CPU splits constants across multiple instructions).
88
89 return (char*) 0xffffffffffff;
90 }
91
92 address os::Posix::ucontext_get_pc(const ucontext_t * uc) {
93 return (address)uc->uc_mcontext.pc;
94 }
95
96 void os::Posix::ucontext_set_pc(ucontext_t * uc, address pc) {
97 uc->uc_mcontext.pc = (intptr_t)pc;
98 }
99
100 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
101 return (intptr_t*)uc->uc_mcontext.sp;
102 }
103
104 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
105 return (intptr_t*)uc->uc_mcontext.regs[REG_FP];
106 }
107
108 address os::fetch_frame_from_context(const void* ucVoid,
109 intptr_t** ret_sp, intptr_t** ret_fp) {
110
111 address epc;
112 const ucontext_t* uc = (const ucontext_t*)ucVoid;
113
114 if (uc != nullptr) {
115 epc = os::Posix::ucontext_get_pc(uc);
116 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
117 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
118 } else {
119 epc = nullptr;
120 if (ret_sp) *ret_sp = (intptr_t *)nullptr;
121 if (ret_fp) *ret_fp = (intptr_t *)nullptr;
122 }
123
124 return epc;
125 }
126
127 frame os::fetch_frame_from_context(const void* ucVoid) {
128 intptr_t* sp;
129 intptr_t* fp;
130 address epc = fetch_frame_from_context(ucVoid, &sp, &fp);
131 if (!is_readable_pointer(epc)) {
132 // Try to recover from calling into bad memory
133 // Assume new frame has not been set up, the same as
134 // compiled frame stack bang
135 return fetch_compiled_frame_from_context(ucVoid);
136 }
137 return frame(sp, fp, epc);
138 }
139
140 frame os::fetch_compiled_frame_from_context(const void* ucVoid) {
141 const ucontext_t* uc = (const ucontext_t*)ucVoid;
142 // In compiled code, the stack banging is performed before LR
143 // has been saved in the frame. LR is live, and SP and FP
144 // belong to the caller.
145 intptr_t* fp = os::Linux::ucontext_get_fp(uc);
146 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
147 address pc = (address)(uc->uc_mcontext.regs[REG_LR]
148 - NativeInstruction::instruction_size);
149 return frame(sp, fp, pc);
150 }
151
152 // By default, gcc always saves frame pointer rfp on this stack. This
153 // may get turned off by -fomit-frame-pointer.
154 // The "Procedure Call Standard for the Arm 64-bit Architecture" doesn't
155 // specify a location for the frame record within a stack frame (6.4.6).
156 // GCC currently chooses to save it at the top of the frame (lowest address).
157 // This means that using fr->sender_sp() to set the caller's frame _unextended_sp,
158 // as we do in x86, is wrong. Using fr->link() instead only makes sense for
159 // native frames. Setting a correct value for _unextended_sp is important
160 // if this value is later used to get that frame's caller. This will happen
161 // if we end up calling frame::sender_for_compiled_frame(), which will be the
162 // case if the _pc is associated with a CodeBlob that has a _frame_size > 0
163 // (nmethod, runtime stub, safepoint stub, etc).
164 frame os::get_sender_for_C_frame(frame* fr) {
165 address pc = fr->sender_pc();
166 CodeBlob* cb = CodeCache::find_blob(pc);
167 bool use_codeblob = cb != nullptr && cb->frame_size() > 0;
168 assert(!use_codeblob || !Interpreter::contains(pc), "should not be an interpreter frame");
169 intptr_t* sender_sp = use_codeblob ? (fr->link() + frame::metadata_words - cb->frame_size()) : fr->link();
170 return frame(sender_sp, sender_sp, fr->link(), pc, cb, true /* allow_cb_null */);
171 }
172
173 NOINLINE frame os::current_frame() {
174 intptr_t *fp = *(intptr_t **)__builtin_frame_address(0);
175 frame myframe((intptr_t*)os::current_stack_pointer(),
176 (intptr_t*)fp,
177 CAST_FROM_FN_PTR(address, os::current_frame));
178 if (os::is_first_C_frame(&myframe)) {
179 // stack is not walkable
180 return frame();
181 } else {
182 return os::get_sender_for_C_frame(&myframe);
183 }
184 }
185
186 bool PosixSignals::pd_hotspot_signal_handler(int sig, siginfo_t* info,
187 ucontext_t* uc, JavaThread* thread) {
188
189 /*
190 NOTE: does not seem to work on linux.
191 if (info == nullptr || info->si_code <= 0 || info->si_code == SI_NOINFO) {
192 // can't decode this kind of signal
193 info = nullptr;
194 } else {
195 assert(sig == info->si_signo, "bad siginfo");
196 }
197 */
198 // decide if this trap can be handled by a stub
199 address stub = nullptr;
200
201 address pc = nullptr;
202
203 //%note os_trap_1
204 if (info != nullptr && uc != nullptr && thread != nullptr) {
205 pc = (address) os::Posix::ucontext_get_pc(uc);
206
207 address addr = (address) info->si_addr;
208
209 // Make sure the high order byte is sign extended, as it may be masked away by the hardware.
210 if ((uintptr_t(addr) & (uintptr_t(1) << 55)) != 0) {
211 addr = address(uintptr_t(addr) | (uintptr_t(0xFF) << 56));
212 }
213
214 // Handle ALL stack overflow variations here
215 if (sig == SIGSEGV) {
216 // check if fault address is within thread stack
217 if (thread->is_in_full_stack(addr)) {
218 if (os::Posix::handle_stack_overflow(thread, addr, pc, uc, &stub)) {
219 return true; // continue
220 }
221 }
222 }
223
224 if (thread->thread_state() == _thread_in_Java) {
225 // Java thread running in Java code => find exception handler if any
226 // a fault inside compiled code, the interpreter, or a stub
227
228 // Handle signal from NativeJump::patch_verified_entry().
229 if ((sig == SIGILL || sig == SIGTRAP)
230 && nativeInstruction_at(pc)->is_sigill_not_entrant()) {
231 if (TraceTraps) {
232 tty->print_cr("trap: not_entrant (%s)", (sig == SIGTRAP) ? "SIGTRAP" : "SIGILL");
233 }
234 stub = SharedRuntime::get_handle_wrong_method_stub();
235 } else if (sig == SIGSEGV && SafepointMechanism::is_poll_address((address)info->si_addr)) {
236 stub = SharedRuntime::get_poll_stub(pc);
237 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
238 // BugId 4454115: A read from a MappedByteBuffer can fault
239 // here if the underlying file has been truncated.
240 // Do not crash the VM in such a case.
241 CodeBlob* cb = CodeCache::find_blob(pc);
242 nmethod* nm = (cb != nullptr) ? cb->as_nmethod_or_null() : nullptr;
243 bool is_unsafe_memory_access = (thread->doing_unsafe_access() && UnsafeMemoryAccess::contains_pc(pc));
244 if ((nm != nullptr && nm->has_unsafe_access()) || is_unsafe_memory_access) {
245 address next_pc = pc + NativeCall::instruction_size;
246 if (is_unsafe_memory_access) {
247 next_pc = UnsafeMemoryAccess::page_error_continue_pc(pc);
248 }
249 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
250 }
251 } else if (sig == SIGILL && nativeInstruction_at(pc)->is_stop()) {
252 // A pointer to the message will have been placed in r0
253 const char *detail_msg = (const char *)(uc->uc_mcontext.regs[0]);
254 const char *msg = "stop";
255 if (TraceTraps) {
256 tty->print_cr("trap: %s: (SIGILL)", msg);
257 }
258
259 // End life with a fatal error, message and detail message and the context.
260 // Note: no need to do any post-processing here (e.g. signal chaining)
261 VMError::report_and_die(thread, uc, nullptr, 0, msg, "%s", detail_msg);
262
263 ShouldNotReachHere();
264
265 }
266 else
267
268 if (sig == SIGFPE &&
269 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
270 stub =
271 SharedRuntime::
272 continuation_for_implicit_exception(thread,
273 pc,
274 SharedRuntime::
275 IMPLICIT_DIVIDE_BY_ZERO);
276 } else if (sig == SIGSEGV &&
277 MacroAssembler::uses_implicit_null_check((void*)addr)) {
278 // Determination of interpreter/vtable stub/compiled code null exception
279 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
280 }
281 } else if ((thread->thread_state() == _thread_in_vm ||
282 thread->thread_state() == _thread_in_native) &&
283 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
284 thread->doing_unsafe_access()) {
285 address next_pc = pc + NativeCall::instruction_size;
286 if (UnsafeMemoryAccess::contains_pc(pc)) {
287 next_pc = UnsafeMemoryAccess::page_error_continue_pc(pc);
288 }
289 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
290 }
291
292 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
293 // and the heap gets shrunk before the field access.
294 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
295 address addr = JNI_FastGetField::find_slowcase_pc(pc);
296 if (addr != (address)-1) {
297 stub = addr;
298 }
299 }
300 }
301
302 if (stub != nullptr) {
303 // save all thread context in case we need to restore it
304 if (thread != nullptr) thread->set_saved_exception_pc(pc);
305
306 os::Posix::ucontext_set_pc(uc, stub);
307 return true;
308 }
309
310 return false; // Mute compiler
311 }
312
313 void os::Linux::init_thread_fpu_state(void) {
314 }
315
316 int os::Linux::get_fpu_control_word(void) {
317 return 0;
318 }
319
320 void os::Linux::set_fpu_control_word(int fpu_control) {
321 }
322
323 ////////////////////////////////////////////////////////////////////////////////
324 // thread stack
325
326 // Minimum usable stack sizes required to get to user code. Space for
327 // HotSpot guard pages is added later.
328 size_t os::_compiler_thread_min_stack_allowed = 72 * K;
329 size_t os::_java_thread_min_stack_allowed = 72 * K;
330 size_t os::_vm_internal_thread_min_stack_allowed = 72 * K;
331
332 // return default stack size for thr_type
333 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
334 // default stack size (compiler thread needs larger stack)
335 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
336 return s;
337 }
338
339 /////////////////////////////////////////////////////////////////////////////
340 // helper functions for fatal error handler
341
342 void os::print_context(outputStream *st, const void *context) {
343 if (context == nullptr) return;
344
345 const ucontext_t *uc = (const ucontext_t*)context;
346
347 st->print_cr("Registers:");
348 for (int r = 0; r < 31; r++) {
349 st->print_cr( "R%d=" INTPTR_FORMAT, r, (uintptr_t)uc->uc_mcontext.regs[r]);
350 }
351 st->cr();
352 }
353
354 void os::print_tos_pc(outputStream *st, const void *context) {
355 if (context == nullptr) return;
356
357 const ucontext_t* uc = (const ucontext_t*)context;
358
359 address sp = (address)os::Linux::ucontext_get_sp(uc);
360 print_tos(st, sp);
361 st->cr();
362
363 // Note: it may be unsafe to inspect memory near pc. For example, pc may
364 // point to garbage if entry point in an nmethod is corrupted. Leave
365 // this at the end, and hope for the best.
366 address pc = os::fetch_frame_from_context(uc).pc();
367 print_instructions(st, pc);
368 st->cr();
369 }
370
371 void os::print_register_info(outputStream *st, const void *context, int& continuation) {
372 const int register_count = 32 /* r0-r31 */;
373 int n = continuation;
374 assert(n >= 0 && n <= register_count, "Invalid continuation value");
375 if (context == nullptr || n == register_count) {
376 return;
377 }
378
379 const ucontext_t *uc = (const ucontext_t*)context;
380 while (n < register_count) {
381 // Update continuation with next index before printing location
382 continuation = n + 1;
383 st->print("R%-2d=", n);
384 print_location(st, uc->uc_mcontext.regs[n]);
385 ++n;
386 }
387 }
388
389 void os::setup_fpu() {
390 }
391
392 #ifndef PRODUCT
393 void os::verify_stack_alignment() {
394 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
395 }
396 #endif
397
398 int os::extra_bang_size_in_bytes() {
399 // AArch64 does not require the additional stack bang.
400 return 0;
401 }
402
403 static inline void atomic_copy64(const volatile void *src, volatile void *dst) {
404 *(jlong *) dst = *(const jlong *) src;
405 }
406
407 extern "C" {
408 int SpinPause() {
409 using spin_wait_func_ptr_t = void (*)();
410 spin_wait_func_ptr_t func = CAST_TO_FN_PTR(spin_wait_func_ptr_t, StubRoutines::aarch64::spin_wait());
411 assert(func != nullptr, "StubRoutines::aarch64::spin_wait must not be null.");
412 (*func)();
413 // If StubRoutines::aarch64::spin_wait consists of only a RET,
414 // SpinPause can be considered as implemented. There will be a sequence
415 // of instructions for:
416 // - call of SpinPause
417 // - load of StubRoutines::aarch64::spin_wait stub pointer
418 // - indirect call of the stub
419 // - return from the stub
420 // - return from SpinPause
421 // So '1' always is returned.
422 return 1;
423 }
424
425 void _Copy_conjoint_jshorts_atomic(const jshort* from, jshort* to, size_t count) {
426 if (from > to) {
427 const jshort *end = from + count;
428 while (from < end)
429 *(to++) = *(from++);
430 }
431 else if (from < to) {
432 const jshort *end = from;
433 from += count - 1;
434 to += count - 1;
435 while (from >= end)
436 *(to--) = *(from--);
437 }
438 }
439 void _Copy_conjoint_jints_atomic(const jint* from, jint* to, size_t count) {
440 if (from > to) {
441 const jint *end = from + count;
442 while (from < end)
443 *(to++) = *(from++);
444 }
445 else if (from < to) {
446 const jint *end = from;
447 from += count - 1;
448 to += count - 1;
449 while (from >= end)
450 *(to--) = *(from--);
451 }
452 }
453
454 void _Copy_conjoint_jlongs_atomic(const jlong* from, jlong* to, size_t count) {
455 if (from > to) {
456 const jlong *end = from + count;
457 while (from < end)
458 atomic_copy64(from++, to++);
459 }
460 else if (from < to) {
461 const jlong *end = from;
462 from += count - 1;
463 to += count - 1;
464 while (from >= end)
465 atomic_copy64(from--, to--);
466 }
467 }
468
469 void _Copy_arrayof_conjoint_bytes(const HeapWord* from,
470 HeapWord* to,
471 size_t count) {
472 memmove(to, from, count);
473 }
474 void _Copy_arrayof_conjoint_jshorts(const HeapWord* from,
475 HeapWord* to,
476 size_t count) {
477 memmove(to, from, count * 2);
478 }
479 void _Copy_arrayof_conjoint_jints(const HeapWord* from,
480 HeapWord* to,
481 size_t count) {
482 memmove(to, from, count * 4);
483 }
484 void _Copy_arrayof_conjoint_jlongs(const HeapWord* from,
485 HeapWord* to,
486 size_t count) {
487 memmove(to, from, count * 8);
488 }
489 };