1 /*
2 * Copyright (c) 2003, 2007, Oracle and/or its affiliates. All rights reserved.
3 * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.
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 // do not include precompiled header file
27 #include "incls/_os_linux_zero.cpp.incl"
28
29 address os::current_stack_pointer() {
30 address dummy = (address) &dummy;
31 return dummy;
32 }
33
34 frame os::get_sender_for_C_frame(frame* fr) {
35 ShouldNotCallThis();
36 }
37
38 frame os::current_frame() {
39 // The only thing that calls this is the stack printing code in
40 // VMError::report:
41 // - Step 110 (printing stack bounds) uses the sp in the frame
42 // to determine the amount of free space on the stack. We
43 // set the sp to a close approximation of the real value in
44 // order to allow this step to complete.
45 // - Step 120 (printing native stack) tries to walk the stack.
46 // The frame we create has a NULL pc, which is ignored as an
47 // invalid frame.
48 frame dummy = frame();
49 dummy.set_sp((intptr_t *) current_stack_pointer());
50 return dummy;
51 }
52
53 char* os::non_memory_address_word() {
54 // Must never look like an address returned by reserve_memory,
55 // even in its subfields (as defined by the CPU immediate fields,
56 // if the CPU splits constants across multiple instructions).
57 #ifdef SPARC
58 // On SPARC, 0 != %hi(any real address), because there is no
59 // allocation in the first 1Kb of the virtual address space.
60 return (char *) 0;
61 #else
62 // This is the value for x86; works pretty well for PPC too.
63 return (char *) -1;
64 #endif // SPARC
65 }
66
67 void os::initialize_thread() {
68 // Nothing to do.
69 }
70
71 address os::Linux::ucontext_get_pc(ucontext_t* uc) {
72 ShouldNotCallThis();
73 }
74
75 ExtendedPC os::fetch_frame_from_context(void* ucVoid,
76 intptr_t** ret_sp,
77 intptr_t** ret_fp) {
78 ShouldNotCallThis();
79 }
80
81 frame os::fetch_frame_from_context(void* ucVoid) {
82 ShouldNotCallThis();
83 }
84
85 extern "C" int
86 JVM_handle_linux_signal(int sig,
87 siginfo_t* info,
88 void* ucVoid,
89 int abort_if_unrecognized) {
90 ucontext_t* uc = (ucontext_t*) ucVoid;
91
92 Thread* t = ThreadLocalStorage::get_thread_slow();
93
94 SignalHandlerMark shm(t);
95
96 // Note: it's not uncommon that JNI code uses signal/sigset to
97 // install then restore certain signal handler (e.g. to temporarily
98 // block SIGPIPE, or have a SIGILL handler when detecting CPU
99 // type). When that happens, JVM_handle_linux_signal() might be
100 // invoked with junk info/ucVoid. To avoid unnecessary crash when
101 // libjsig is not preloaded, try handle signals that do not require
102 // siginfo/ucontext first.
103
104 if (sig == SIGPIPE || sig == SIGXFSZ) {
105 // allow chained handler to go first
106 if (os::Linux::chained_handler(sig, info, ucVoid)) {
107 return true;
108 } else {
109 if (PrintMiscellaneous && (WizardMode || Verbose)) {
110 char buf[64];
111 warning("Ignoring %s - see bugs 4229104 or 646499219",
112 os::exception_name(sig, buf, sizeof(buf)));
113 }
114 return true;
115 }
116 }
117
118 JavaThread* thread = NULL;
119 VMThread* vmthread = NULL;
120 if (os::Linux::signal_handlers_are_installed) {
121 if (t != NULL ){
122 if(t->is_Java_thread()) {
123 thread = (JavaThread*)t;
124 }
125 else if(t->is_VM_thread()){
126 vmthread = (VMThread *)t;
127 }
128 }
129 }
130
131 if (info != NULL && thread != NULL) {
132 // Handle ALL stack overflow variations here
133 if (sig == SIGSEGV) {
134 address addr = (address) info->si_addr;
135
136 // check if fault address is within thread stack
137 if (addr < thread->stack_base() &&
138 addr >= thread->stack_base() - thread->stack_size()) {
139 // stack overflow
140 if (thread->in_stack_yellow_zone(addr)) {
141 thread->disable_stack_yellow_zone();
142 ShouldNotCallThis();
143 }
144 else if (thread->in_stack_red_zone(addr)) {
145 thread->disable_stack_red_zone();
146 ShouldNotCallThis();
147 }
148 else {
149 // Accessing stack address below sp may cause SEGV if
150 // current thread has MAP_GROWSDOWN stack. This should
151 // only happen when current thread was created by user
152 // code with MAP_GROWSDOWN flag and then attached to VM.
153 // See notes in os_linux.cpp.
154 if (thread->osthread()->expanding_stack() == 0) {
155 thread->osthread()->set_expanding_stack();
156 if (os::Linux::manually_expand_stack(thread, addr)) {
157 thread->osthread()->clear_expanding_stack();
158 return true;
159 }
160 thread->osthread()->clear_expanding_stack();
161 }
162 else {
163 fatal("recursive segv. expanding stack.");
164 }
165 }
166 }
167 }
168
169 /*if (thread->thread_state() == _thread_in_Java) {
170 ShouldNotCallThis();
171 }
172 else*/ if (thread->thread_state() == _thread_in_vm &&
173 sig == SIGBUS && thread->doing_unsafe_access()) {
174 ShouldNotCallThis();
175 }
176
177 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC
178 // kicks in and the heap gets shrunk before the field access.
179 /*if (sig == SIGSEGV || sig == SIGBUS) {
180 address addr = JNI_FastGetField::find_slowcase_pc(pc);
181 if (addr != (address)-1) {
182 stub = addr;
183 }
184 }*/
185
186 // Check to see if we caught the safepoint code in the process
187 // of write protecting the memory serialization page. It write
188 // enables the page immediately after protecting it so we can
189 // just return to retry the write.
190 if (sig == SIGSEGV &&
191 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
192 // Block current thread until permission is restored.
193 os::block_on_serialize_page_trap();
194 return true;
195 }
196 }
197
198 // signal-chaining
199 if (os::Linux::chained_handler(sig, info, ucVoid)) {
200 return true;
201 }
202
203 if (!abort_if_unrecognized) {
204 // caller wants another chance, so give it to him
205 return false;
206 }
207
208 #ifndef PRODUCT
209 if (sig == SIGSEGV) {
210 fatal("\n#"
211 "\n# /--------------------\\"
212 "\n# | segmentation fault |"
213 "\n# \\---\\ /--------------/"
214 "\n# /"
215 "\n# [-] |\\_/| "
216 "\n# (+)=C |o o|__ "
217 "\n# | | =-*-=__\\ "
218 "\n# OOO c_c_(___)");
219 }
220 #endif // !PRODUCT
221
222 const char *fmt = "caught unhandled signal %d";
223 char buf[64];
224
225 sprintf(buf, fmt, sig);
226 fatal(buf);
227 }
228
229 void os::Linux::init_thread_fpu_state(void) {
230 // Nothing to do
231 }
232
233 int os::Linux::get_fpu_control_word() {
234 ShouldNotCallThis();
235 }
236
237 void os::Linux::set_fpu_control_word(int fpu) {
238 ShouldNotCallThis();
239 }
240
241 bool os::is_allocatable(size_t bytes) {
242 #ifdef _LP64
243 return true;
244 #else
245 if (bytes < 2 * G) {
246 return true;
247 }
248
249 char* addr = reserve_memory(bytes, NULL);
250
251 if (addr != NULL) {
252 release_memory(addr, bytes);
253 }
254
255 return addr != NULL;
256 #endif // _LP64
257 }
258
259 ///////////////////////////////////////////////////////////////////////////////
260 // thread stack
261
262 size_t os::Linux::min_stack_allowed = 64 * K;
263
264 bool os::Linux::supports_variable_stack_size() {
265 return true;
266 }
267
268 size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
269 #ifdef _LP64
270 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
271 #else
272 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
273 #endif // _LP64
274 return s;
275 }
276
277 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
278 // Only enable glibc guard pages for non-Java threads
279 // (Java threads have HotSpot guard pages)
280 return (thr_type == java_thread ? 0 : page_size());
281 }
282
283 static void current_stack_region(address *bottom, size_t *size) {
284 pthread_attr_t attr;
285 int res = pthread_getattr_np(pthread_self(), &attr);
286 if (res != 0) {
287 if (res == ENOMEM) {
288 vm_exit_out_of_memory(0, "pthread_getattr_np");
289 }
290 else {
291 fatal(err_msg("pthread_getattr_np failed with errno = %d", res));
292 }
293 }
294
295 address stack_bottom;
296 size_t stack_bytes;
297 res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes);
298 if (res != 0) {
299 fatal(err_msg("pthread_attr_getstack failed with errno = %d", res));
300 }
301 address stack_top = stack_bottom + stack_bytes;
302
303 // The block of memory returned by pthread_attr_getstack() includes
304 // guard pages where present. We need to trim these off.
305 size_t page_bytes = os::Linux::page_size();
306 assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack");
307
308 size_t guard_bytes;
309 res = pthread_attr_getguardsize(&attr, &guard_bytes);
310 if (res != 0) {
311 fatal(err_msg("pthread_attr_getguardsize failed with errno = %d", res));
312 }
313 int guard_pages = align_size_up(guard_bytes, page_bytes) / page_bytes;
314 assert(guard_bytes == guard_pages * page_bytes, "unaligned guard");
315
316 #ifdef IA64
317 // IA64 has two stacks sharing the same area of memory, a normal
318 // stack growing downwards and a register stack growing upwards.
319 // Guard pages, if present, are in the centre. This code splits
320 // the stack in two even without guard pages, though in theory
321 // there's nothing to stop us allocating more to the normal stack
322 // or more to the register stack if one or the other were found
323 // to grow faster.
324 int total_pages = align_size_down(stack_bytes, page_bytes) / page_bytes;
325 stack_bottom += (total_pages - guard_pages) / 2 * page_bytes;
326 #endif // IA64
327
328 stack_bottom += guard_bytes;
329
330 pthread_attr_destroy(&attr);
331
332 // The initial thread has a growable stack, and the size reported
333 // by pthread_attr_getstack is the maximum size it could possibly
334 // be given what currently mapped. This can be huge, so we cap it.
335 if (os::Linux::is_initial_thread()) {
336 stack_bytes = stack_top - stack_bottom;
337
338 if (stack_bytes > JavaThread::stack_size_at_create())
339 stack_bytes = JavaThread::stack_size_at_create();
340
341 stack_bottom = stack_top - stack_bytes;
342 }
343
344 assert(os::current_stack_pointer() >= stack_bottom, "should do");
345 assert(os::current_stack_pointer() < stack_top, "should do");
346
347 *bottom = stack_bottom;
348 *size = stack_top - stack_bottom;
349 }
350
351 address os::current_stack_base() {
352 address bottom;
353 size_t size;
354 current_stack_region(&bottom, &size);
355 return bottom + size;
356 }
357
358 size_t os::current_stack_size() {
359 // stack size includes normal stack and HotSpot guard pages
360 address bottom;
361 size_t size;
362 current_stack_region(&bottom, &size);
363 return size;
364 }
365
366 /////////////////////////////////////////////////////////////////////////////
367 // helper functions for fatal error handler
368
369 void os::print_context(outputStream* st, void* context) {
370 ShouldNotCallThis();
371 }
372
373 /////////////////////////////////////////////////////////////////////////////
374 // Stubs for things that would be in linux_zero.s if it existed.
375 // You probably want to disassemble these monkeys to check they're ok.
376
377 extern "C" {
378 int SpinPause() {
379 }
380
381 int SafeFetch32(int *adr, int errValue) {
382 int value = errValue;
383 value = *adr;
384 return value;
385 }
386 intptr_t SafeFetchN(intptr_t *adr, intptr_t errValue) {
387 intptr_t value = errValue;
388 value = *adr;
389 return value;
390 }
391
392 void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) {
393 if (from > to) {
394 jshort *end = from + count;
395 while (from < end)
396 *(to++) = *(from++);
397 }
398 else if (from < to) {
399 jshort *end = from;
400 from += count - 1;
401 to += count - 1;
402 while (from >= end)
403 *(to--) = *(from--);
404 }
405 }
406 void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) {
407 if (from > to) {
408 jint *end = from + count;
409 while (from < end)
410 *(to++) = *(from++);
411 }
412 else if (from < to) {
413 jint *end = from;
414 from += count - 1;
415 to += count - 1;
416 while (from >= end)
417 *(to--) = *(from--);
418 }
419 }
420 void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) {
421 if (from > to) {
422 jlong *end = from + count;
423 while (from < end)
424 os::atomic_copy64(from++, to++);
425 }
426 else if (from < to) {
427 jlong *end = from;
428 from += count - 1;
429 to += count - 1;
430 while (from >= end)
431 os::atomic_copy64(from--, to--);
432 }
433 }
434
435 void _Copy_arrayof_conjoint_bytes(HeapWord* from,
436 HeapWord* to,
437 size_t count) {
438 memmove(to, from, count);
439 }
440 void _Copy_arrayof_conjoint_jshorts(HeapWord* from,
441 HeapWord* to,
442 size_t count) {
443 memmove(to, from, count * 2);
444 }
445 void _Copy_arrayof_conjoint_jints(HeapWord* from,
446 HeapWord* to,
447 size_t count) {
448 memmove(to, from, count * 4);
449 }
450 void _Copy_arrayof_conjoint_jlongs(HeapWord* from,
451 HeapWord* to,
452 size_t count) {
453 memmove(to, from, count * 8);
454 }
455 };
456
457 /////////////////////////////////////////////////////////////////////////////
458 // Implementations of atomic operations not supported by processors.
459 // -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html
460
461 #ifndef _LP64
462 extern "C" {
463 long long unsigned int __sync_val_compare_and_swap_8(
464 volatile void *ptr,
465 long long unsigned int oldval,
466 long long unsigned int newval) {
467 ShouldNotCallThis();
468 }
469 };
470 #endif // !_LP64