Line data Source code
1 : /* src/vm/jit/trap.cpp - hardware traps
2 :
3 : Copyright (C) 1996-2013
4 : CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO
5 : Copyright (C) 2009 Theobroma Systems Ltd.
6 :
7 : This file is part of CACAO.
8 :
9 : This program is free software; you can redistribute it and/or
10 : modify it under the terms of the GNU General Public License as
11 : published by the Free Software Foundation; either version 2, or (at
12 : your option) any later version.
13 :
14 : This program is distributed in the hope that it will be useful, but
15 : WITHOUT ANY WARRANTY; without even the implied warranty of
16 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 : General Public License for more details.
18 :
19 : You should have received a copy of the GNU General Public License
20 : along with this program; if not, write to the Free Software
21 : Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 : 02110-1301, USA.
23 :
24 : */
25 :
26 :
27 : #include "config.h"
28 :
29 : #include <stdint.h>
30 :
31 : /* Include machine dependent trap stuff. */
32 :
33 : #include "md.hpp"
34 : #include "md-trap.hpp"
35 :
36 : #include "mm/memory.hpp"
37 :
38 : #include "native/llni.hpp"
39 :
40 : #include "toolbox/logging.hpp"
41 :
42 : #include "vm/exceptions.hpp"
43 : #include "vm/options.hpp"
44 : #include "vm/os.hpp"
45 : #include "vm/vm.hpp"
46 :
47 : #include "vm/jit/code.hpp"
48 : #include "vm/jit/disass.hpp"
49 : #include "vm/jit/executionstate.hpp"
50 : #include "vm/jit/jit.hpp"
51 : #include "vm/jit/methodtree.hpp"
52 : #include "vm/jit/patcher-common.hpp"
53 : #include "vm/jit/replace.hpp"
54 : #include "vm/jit/stacktrace.hpp"
55 : #include "vm/jit/trap.hpp"
56 :
57 : #if defined(__S390__)
58 : #include "vm/jit/s390/codegen.hpp"
59 : #else
60 : #define N_PV_OFFSET 0
61 : #endif
62 :
63 : /**
64 : * Mmap the first memory page to support hardware exceptions and check
65 : * the maximum hardware trap displacement on the architectures where
66 : * it is required (TRAP_INSTRUCTION_IS_LOAD defined to 1).
67 : */
68 163 : void trap_init(void)
69 : {
70 163 : TRACESUBSYSTEMINITIALIZATION("trap_init");
71 :
72 : /* If requested we mmap a memory page at address 0x0,
73 : so our hardware-exceptions work. */
74 :
75 163 : if (opt_AlwaysMmapFirstPage) {
76 0 : int pagesize = os::getpagesize();
77 0 : (void) os::mmap_anonymous(NULL, pagesize, PROT_NONE, MAP_PRIVATE | MAP_FIXED);
78 : }
79 :
80 : #if !defined(TRAP_INSTRUCTION_IS_LOAD)
81 : # error TRAP_INSTRUCTION_IS_LOAD is not defined in your md-trap.h
82 : #endif
83 :
84 : #if TRAP_INSTRUCTION_IS_LOAD == 1
85 : /* Check if we get into trouble with our hardware-exceptions. */
86 :
87 163 : if (TRAP_END > OFFSET(java_bytearray_t, data))
88 0 : vm_abort("trap_init: maximum hardware trap displacement is greater than the array-data offset: %d > %d", TRAP_END, OFFSET(java_bytearray_t, data));
89 : #endif
90 163 : }
91 :
92 :
93 : /**
94 : * Handles the signal which is generated by trap instructions, caught
95 : * by a signal handler and calls the correct function.
96 : *
97 : * @param sig signal number
98 : * @param xpc exception PC
99 : * @param context pointer to OS dependent machine context
100 : */
101 197445 : void trap_handle(int sig, void *xpc, void *context)
102 : {
103 : executionstate_t es;
104 : stackframeinfo_t sfi;
105 : trapinfo_t trp;
106 :
107 : #if !defined(NDEBUG)
108 : // Sanity checking the XPC.
109 197445 : if (xpc == NULL)
110 0 : vm_abort("trap_handle: The program counter is NULL!");
111 : #endif
112 :
113 : #if defined(__ALPHA__) || defined(__ARM__) || defined(__I386__) || defined(__MIPS__) || defined(__POWERPC__) || defined(__POWERPC64__) || defined(__S390__) || defined(__X86_64__)
114 : # if !defined(NDEBUG)
115 : /* Perform a sanity check on our execution state functions. */
116 :
117 197445 : executionstate_sanity_check(context);
118 : # endif
119 :
120 : /* Read execution state from current context. */
121 :
122 197445 : es.code = NULL;
123 197445 : md_executionstate_read(&es, context);
124 :
125 : //# define TRAP_TRACE_VERBOSE
126 : # if !defined(NDEBUG) && defined(TRAP_TRACE_VERBOSE)
127 : /* Dump contents of execution state */
128 :
129 : if (opt_TraceTraps) {
130 : log_println("[trap_handle: dumping execution state BEFORE ...]");
131 : executionstate_println(&es);
132 : }
133 : # endif
134 : #endif
135 :
136 : // Extract information from executionstate
137 197445 : void* pv = es.pv; // Maybe null, resolved during stackframeinfo creation.
138 197445 : void* sp = es.sp;
139 : #if defined(__I386__) || defined(__X86_64__)
140 197445 : void* ra = xpc; // Return address is equal to XPC.
141 : #else
142 : void* ra = es.ra; // This is correct for leafs.
143 : #endif
144 :
145 : // Decode machine-dependent trap instruction.
146 197445 : bool decode_result = md_trap_decode(&trp, sig, xpc, &es);
147 :
148 : // Check if the trap instruction is valid and was decoded
149 : // successfully.
150 197445 : if (!decode_result) {
151 : // Check if the PC has been patched during our way to this
152 : // trap handler (see PR85).
153 : // NOTE: Some archs use SIGILL for other traps too, but it's OK to
154 : // do this check anyway because it will fail.
155 1 : if (patcher_is_patched_at(xpc) == true) {
156 1 : if (opt_PrintWarnings)
157 0 : log_println("trap_handle: Detected patcher race condition (PR85) at %p", xpc);
158 1 : return;
159 : }
160 :
161 : // We have a problem...
162 0 : vm_abort_disassemble(xpc, 1, "trap_handle: Unknown trap instruction at %p", xpc);
163 : }
164 :
165 : // For convenience only.
166 197444 : int type = trp.type;
167 197444 : intptr_t val = trp.value;
168 :
169 : /* Do some preparations before we enter the nativeworld. */
170 : /* BEFORE: creating stackframeinfo */
171 :
172 : // Prevent compiler warnings.
173 197444 : int32_t index = 0;
174 197444 : java_handle_t* o = NULL;
175 197444 : methodinfo* m = NULL;
176 :
177 197444 : switch (type) {
178 : case TRAP_ArrayIndexOutOfBoundsException:
179 : /* Get the index into the array causing the exception. */
180 :
181 25 : index = (int32_t) val;
182 25 : break;
183 :
184 : case TRAP_ClassCastException:
185 : /* Wrap the value into a handle, as it is a reference. */
186 :
187 10 : o = LLNI_WRAP((java_object_t *) val);
188 10 : break;
189 :
190 : case TRAP_COMPILER:
191 : /* We need to fixup the XPC, SP and RA here because they
192 : all might point into the compiler stub instead of the
193 : calling method. */
194 :
195 126224 : MD_TRAP_COMPILER_FIXUP(xpc, ra, sp, pv);
196 :
197 : /* In this case the passed PV points to the compiler stub. We
198 : get the methodinfo pointer here and set PV to NULL so
199 : stacktrace_stackframeinfo_add determines the PV for the
200 : parent Java method. */
201 :
202 126224 : m = code_get_methodinfo_for_pv(pv);
203 126224 : pv = NULL;
204 :
205 : break;
206 :
207 : default:
208 : /* do nothing */
209 : break;
210 : }
211 :
212 : #if !defined(NDEBUG)
213 : // Trace this trap.
214 197444 : if (opt_TraceTraps)
215 0 : log_println("[trap_handle: sig=%d, type=%d, val=%p, pv=%p, sp=%p, ra=%p, xpc=%p]", sig, type, val, pv, sp, ra, xpc);
216 : #endif
217 :
218 : /* Fill and add a stackframeinfo. */
219 :
220 197444 : stacktrace_stackframeinfo_add(&sfi, pv, sp, ra, xpc);
221 :
222 : /* Get resulting exception (or pointer to compiled method). */
223 :
224 : java_handle_t* p;
225 197444 : void* entry = 0;
226 197444 : bool was_patched = false;
227 : #if defined(ENABLE_REPLACEMENT)
228 : bool was_replaced;
229 : #endif
230 :
231 197444 : switch (type) {
232 : case TRAP_NullPointerException:
233 22 : p = exceptions_new_nullpointerexception();
234 22 : break;
235 :
236 : case TRAP_ArithmeticException:
237 8 : p = exceptions_new_arithmeticexception();
238 8 : break;
239 :
240 : case TRAP_ArrayIndexOutOfBoundsException:
241 25 : p = exceptions_new_arrayindexoutofboundsexception(index);
242 25 : break;
243 :
244 : case TRAP_ArrayStoreException:
245 6 : p = exceptions_new_arraystoreexception();
246 6 : break;
247 :
248 : case TRAP_ClassCastException:
249 10 : p = exceptions_new_classcastexception(o);
250 10 : break;
251 :
252 : case TRAP_CHECK_EXCEPTION:
253 3 : p = exceptions_fillinstacktrace();
254 3 : break;
255 :
256 : case TRAP_PATCHER:
257 71146 : p = NULL;
258 : #if defined(ENABLE_REPLACEMENT)
259 : was_replaced = replace_handler((uint8_t*) xpc, &es);
260 : if (was_replaced)
261 : break;
262 : #endif
263 71146 : was_patched = patcher_handler((uint8_t*) xpc);
264 71146 : break;
265 :
266 : case TRAP_COMPILER:
267 126224 : p = NULL;
268 126224 : entry = jit_compile_handle(m, sfi.pv, ra, (void*) val);
269 126224 : break;
270 :
271 : #if defined(__I386__) && defined(ENABLE_REPLACEMENT)
272 : # warning Port the below stuff to use the patching subsystem.
273 : case TRAP_COUNTDOWN:
274 : p = NULL;
275 : (void) replace_handler((uint8_t*) xpc - 13, &es);
276 : break;
277 : #endif
278 :
279 : default:
280 : /* Let's try to get a backtrace. */
281 :
282 0 : (void) methodtree_find(xpc);
283 :
284 : /* If that does not work, print more debug info. */
285 :
286 0 : vm_abort_disassemble(xpc, 1, "trap_handle: Unknown hardware exception type %d", type);
287 :
288 : /* keep compiler happy */
289 :
290 0 : p = NULL;
291 : }
292 :
293 : /* Remove stackframeinfo. */
294 :
295 197444 : stacktrace_stackframeinfo_remove(&sfi);
296 :
297 : #if defined(__ALPHA__) || defined(__ARM__) || defined(__I386__) || defined(__MIPS__) || defined(__POWERPC__) || defined(__POWERPC64__) || defined(__S390__) || defined(__X86_64__)
298 : /* Update execution state and set registers. */
299 : /* AFTER: removing stackframeinfo */
300 :
301 197444 : switch (type) {
302 : case TRAP_COMPILER:
303 : // The normal case for a compiler trap is to jump directly to
304 : // the newly compiled method.
305 :
306 126224 : if (entry != NULL) {
307 126220 : es.pc = (uint8_t *) (uintptr_t) entry;
308 : // The s390 executionstate offsets pv, so we need to
309 : // compensate here.
310 126220 : es.pv = (uint8_t *) (uintptr_t) entry - N_PV_OFFSET;
311 126220 : break;
312 : }
313 :
314 : // In case of an exception during JIT compilation, we fetch
315 : // the exception here and proceed with exception handling.
316 :
317 4 : p = exceptions_get_and_clear_exception();
318 4 : assert(p != NULL);
319 :
320 : // Remove RA from stack on some archs.
321 :
322 4 : es.sp = (uint8_t*) sp;
323 :
324 : // Get and set the PV from the parent Java method.
325 :
326 4 : es.pv = (uint8_t*) md_codegen_get_pv_from_pc(ra) - N_PV_OFFSET;
327 :
328 : // Now fall-through to default exception handling.
329 :
330 4 : goto trap_handle_exception;
331 :
332 : case TRAP_PATCHER:
333 : #if defined(ENABLE_REPLACEMENT)
334 : // If on-stack-replacement suceeded, we are not allowed to touch
335 : // the execution state. We assume that there was no exception.
336 :
337 : if (was_replaced) {
338 : java_object_t *e = exceptions_get_exception();
339 : if (e)
340 : exceptions_print_stacktrace();
341 : assert(e == NULL);
342 : break;
343 : }
344 : #endif
345 :
346 : // The normal case for a patcher trap is to continue execution at
347 : // the trap instruction. On some archs the PC may point after the
348 : // trap instruction, so we reset it here.
349 :
350 71146 : if (was_patched) {
351 71133 : java_object_t *e = exceptions_get_exception();
352 71133 : if (e)
353 0 : exceptions_print_stacktrace();
354 71133 : assert(e == NULL);
355 71133 : es.pc = (uint8_t *) (uintptr_t) xpc;
356 71133 : break;
357 : }
358 :
359 : // In case patching was not successful, we try to fetch the pending
360 : // exception here.
361 :
362 13 : p = exceptions_get_and_clear_exception();
363 :
364 : // If there is no pending exception, we continue execution behind
365 : // the position still in need of patching. Normally this would
366 : // indicate an error in the patching subsystem, but others might
367 : // want to piggyback patchers and we want to be able to provide
368 : // "reusable trap points" and avoid inifinite loops here. This is
369 : // especially useful to implement breakpoints or profiling points
370 : // of any kind. So before changing the trap logic, think about
371 : // utilizing the patching subsystem on your quest. :)
372 :
373 13 : if (p == NULL) {
374 : #if !defined(NDEBUG)
375 0 : if (opt_PrintWarnings)
376 0 : log_println("trap_handle: Detected reusable trap at %p", xpc);
377 : #endif
378 0 : es.pc = (uint8_t *) (uintptr_t) xpc;
379 0 : es.pc += REPLACEMENT_PATCH_SIZE;
380 0 : break;
381 : }
382 :
383 : // Fall-through to default exception handling.
384 :
385 : trap_handle_exception:
386 : default:
387 91 : if (p != NULL) {
388 : #if defined(__ALPHA__) || defined(__I386__) || defined(__X86_64__)
389 : // Perform stack unwinding for exceptions on execution state.
390 91 : es.pc = (uint8_t *) (uintptr_t) xpc;
391 91 : es.pv = (uint8_t *) (uintptr_t) sfi.pv;
392 91 : executionstate_unwind_exception(&es, p);
393 :
394 : // Pass the exception object to the exception handler.
395 91 : es.intregs[REG_ITMP1_XPTR] = (uintptr_t) LLNI_DIRECT(p);
396 : #else
397 : es.intregs[REG_ITMP1_XPTR] = (uintptr_t) LLNI_DIRECT(p);
398 : es.intregs[REG_ITMP2_XPC] = (uintptr_t) xpc;
399 : es.pc = (uint8_t *) (uintptr_t) asm_handle_exception;
400 : #endif
401 : }
402 : }
403 :
404 : /* Write back execution state to current context. */
405 :
406 197444 : md_executionstate_write(&es, context);
407 :
408 : # if !defined(NDEBUG) && defined(TRAP_TRACE_VERBOSE)
409 : /* Dump contents of execution state */
410 :
411 : if (opt_TraceTraps) {
412 : log_println("[trap_handle: dumping execution state AFTER ...]");
413 : executionstate_println(&es);
414 : }
415 : # endif
416 : #endif
417 : }
418 :
419 :
420 : /*
421 : * These are local overrides for various environment variables in Emacs.
422 : * Please do not remove this and leave it at the end of the file, where
423 : * Emacs will automagically detect them.
424 : * ---------------------------------------------------------------------
425 : * Local variables:
426 : * mode: c++
427 : * indent-tabs-mode: t
428 : * c-basic-offset: 4
429 : * tab-width: 4
430 : * End:
431 : * vim:noexpandtab:sw=4:ts=4:
432 : */
|
