projects / gcc.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
history | raw | HEAD
sigtramp-vxworks-target.inc: sigtramp-vxworks: force the stack alignment for x86_64.
[gcc.git] / gcc / ada / init.c
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * I N I T *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2015, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. *
17 * *
18 * As a special exception under Section 7 of GPL version 3, you are granted *
19 * additional permissions described in the GCC Runtime Library Exception, *
20 * version 3.1, as published by the Free Software Foundation. *
21 * *
22 * You should have received a copy of the GNU General Public License and *
23 * a copy of the GCC Runtime Library Exception along with this program; *
24 * see the files COPYING3 and COPYING.RUNTIME respectively. If not, see *
25 * <http://www.gnu.org/licenses/>. *
26 * *
27 * GNAT was originally developed by the GNAT team at New York University. *
28 * Extensive contributions were provided by Ada Core Technologies Inc. *
29 * *
30 ****************************************************************************/
31
32 /* This unit contains initialization circuits that are system dependent.
33 A major part of the functionality involves stack overflow checking.
34 The GCC backend generates probe instructions to test for stack overflow.
35 For details on the exact approach used to generate these probes, see the
36 "Using and Porting GCC" manual, in particular the "Stack Checking" section
37 and the subsection "Specifying How Stack Checking is Done". The handlers
38 installed by this file are used to catch the resulting signals that come
39 from these probes failing (i.e. touching protected pages). */
40
41 /* This file should be kept synchronized with s-init.ads, s-init.adb and the
42 s-init-*.adb variants. All these files implement the required functionality
43 for different targets. */
44
45 /* The following include is here to meet the published VxWorks requirement
46 that the __vxworks header appear before any other include. */
47 #ifdef __vxworks
48 #include "vxWorks.h"
49 #include "version.h" /* for _WRS_VXWORKS_MAJOR */
50 #endif
51
52 #ifdef __ANDROID__
53 #undef __linux__
54 #endif
55
56 #ifdef IN_RTS
57 #include "tconfig.h"
58 #include "tsystem.h"
59 #include <sys/stat.h>
60
61 /* We don't have libiberty, so use malloc. */
62 #define xmalloc(S) malloc (S)
63 #else
64 #include "config.h"
65 #include "system.h"
66 #endif
67
68 #include "adaint.h"
69 #include "raise.h"
70
71 #ifdef __cplusplus
72 extern "C" {
73 #endif
74
75 extern void __gnat_raise_program_error (const char *, int);
76
77 /* Addresses of exception data blocks for predefined exceptions. Tasking_Error
78 is not used in this unit, and the abort signal is only used on IRIX.
79 ??? Revisit this part since IRIX is no longer supported. */
80 extern struct Exception_Data constraint_error;
81 extern struct Exception_Data numeric_error;
82 extern struct Exception_Data program_error;
83 extern struct Exception_Data storage_error;
84
85 /* For the Cert run time we use the regular raise exception routine because
86 Raise_From_Signal_Handler is not available. */
87 #ifdef CERT
88 #define Raise_From_Signal_Handler \
89 __gnat_raise_exception
90 extern void Raise_From_Signal_Handler (struct Exception_Data *, const char *);
91 #else
92 #define Raise_From_Signal_Handler \
93 ada__exceptions__raise_from_signal_handler
94 extern void Raise_From_Signal_Handler (struct Exception_Data *, const char *);
95 #endif
96
97 /* Global values computed by the binder. Note that these variables are
98 declared here, not in the binder file, to avoid having unresolved
99 references in the shared libgnat. */
100 int __gl_main_priority = -1;
101 int __gl_main_cpu = -1;
102 int __gl_time_slice_val = -1;
103 char __gl_wc_encoding = 'n';
104 char __gl_locking_policy = ' ';
105 char __gl_queuing_policy = ' ';
106 char __gl_task_dispatching_policy = ' ';
107 char *__gl_priority_specific_dispatching = 0;
108 int __gl_num_specific_dispatching = 0;
109 char *__gl_interrupt_states = 0;
110 int __gl_num_interrupt_states = 0;
111 int __gl_unreserve_all_interrupts = 0;
112 int __gl_exception_tracebacks = 0;
113 int __gl_exception_tracebacks_symbolic = 0;
114 int __gl_detect_blocking = 0;
115 int __gl_default_stack_size = -1;
116 int __gl_leap_seconds_support = 0;
117 int __gl_canonical_streams = 0;
118 char *__gl_bind_env_addr = NULL;
119
120 /* This value is not used anymore, but kept for bootstrapping purpose. */
121 int __gl_zero_cost_exceptions = 0;
122
123 /* Indication of whether synchronous signal handler has already been
124 installed by a previous call to adainit. */
125 int __gnat_handler_installed = 0;
126
127 #ifndef IN_RTS
128 int __gnat_inside_elab_final_code = 0;
129 /* ??? This variable is obsolete since 2001-08-29 but is kept to allow
130 bootstrap from old GNAT versions (< 3.15). */
131 #endif
132
133 /* HAVE_GNAT_INIT_FLOAT must be set on every targets where a __gnat_init_float
134 is defined. If this is not set then a void implementation will be defined
135 at the end of this unit. */
136 #undef HAVE_GNAT_INIT_FLOAT
137
138 /******************************/
139 /* __gnat_get_interrupt_state */
140 /******************************/
141
142 char __gnat_get_interrupt_state (int);
143
144 /* This routine is called from the runtime as needed to determine the state
145 of an interrupt, as set by an Interrupt_State pragma appearing anywhere
146 in the current partition. The input argument is the interrupt number,
147 and the result is one of the following:
148
149 'n' this interrupt not set by any Interrupt_State pragma
150 'u' Interrupt_State pragma set state to User
151 'r' Interrupt_State pragma set state to Runtime
152 's' Interrupt_State pragma set state to System */
153
154 char
155 __gnat_get_interrupt_state (int intrup)
156 {
157 if (intrup >= __gl_num_interrupt_states)
158 return 'n';
159 else
160 return __gl_interrupt_states [intrup];
161 }
162
163 /***********************************/
164 /* __gnat_get_specific_dispatching */
165 /***********************************/
166
167 char __gnat_get_specific_dispatching (int);
168
169 /* This routine is called from the runtime as needed to determine the
170 priority specific dispatching policy, as set by a
171 Priority_Specific_Dispatching pragma appearing anywhere in the current
172 partition. The input argument is the priority number, and the result
173 is the upper case first character of the policy name, e.g. 'F' for
174 FIFO_Within_Priorities. A space ' ' is returned if no
175 Priority_Specific_Dispatching pragma is used in the partition. */
176
177 char
178 __gnat_get_specific_dispatching (int priority)
179 {
180 if (__gl_num_specific_dispatching == 0)
181 return ' ';
182 else if (priority >= __gl_num_specific_dispatching)
183 return 'F';
184 else
185 return __gl_priority_specific_dispatching [priority];
186 }
187
188 #ifndef IN_RTS
189
190 /**********************/
191 /* __gnat_set_globals */
192 /**********************/
193
194 /* This routine is kept for bootstrapping purposes, since the binder generated
195 file now sets the __gl_* variables directly. */
196
197 void
198 __gnat_set_globals (void)
199 {
200 }
201
202 #endif
203
204 /***************/
205 /* AIX Section */
206 /***************/
207
208 #if defined (_AIX)
209
210 #include <signal.h>
211 #include <sys/time.h>
212
213 /* Some versions of AIX don't define SA_NODEFER. */
214
215 #ifndef SA_NODEFER
216 #define SA_NODEFER 0
217 #endif /* SA_NODEFER */
218
219 /* Versions of AIX before 4.3 don't have nanosleep but provide
220 nsleep instead. */
221
222 #ifndef _AIXVERSION_430
223
224 extern int nanosleep (struct timestruc_t *, struct timestruc_t *);
225
226 int
227 nanosleep (struct timestruc_t *Rqtp, struct timestruc_t *Rmtp)
228 {
229 return nsleep (Rqtp, Rmtp);
230 }
231
232 #endif /* _AIXVERSION_430 */
233
234 static void
235 __gnat_error_handler (int sig,
236 siginfo_t *si ATTRIBUTE_UNUSED,
237 void *ucontext ATTRIBUTE_UNUSED)
238 {
239 struct Exception_Data *exception;
240 const char *msg;
241
242 switch (sig)
243 {
244 case SIGSEGV:
245 /* FIXME: we need to detect the case of a *real* SIGSEGV. */
246 exception = &storage_error;
247 msg = "stack overflow or erroneous memory access";
248 break;
249
250 case SIGBUS:
251 exception = &constraint_error;
252 msg = "SIGBUS";
253 break;
254
255 case SIGFPE:
256 exception = &constraint_error;
257 msg = "SIGFPE";
258 break;
259
260 default:
261 exception = &program_error;
262 msg = "unhandled signal";
263 }
264
265 Raise_From_Signal_Handler (exception, msg);
266 }
267
268 void
269 __gnat_install_handler (void)
270 {
271 struct sigaction act;
272
273 /* Set up signal handler to map synchronous signals to appropriate
274 exceptions. Make sure that the handler isn't interrupted by another
275 signal that might cause a scheduling event! */
276
277 act.sa_flags = SA_NODEFER | SA_RESTART | SA_SIGINFO;
278 act.sa_sigaction = __gnat_error_handler;
279 sigemptyset (&act.sa_mask);
280
281 /* Do not install handlers if interrupt state is "System". */
282 if (__gnat_get_interrupt_state (SIGABRT) != 's')
283 sigaction (SIGABRT, &act, NULL);
284 if (__gnat_get_interrupt_state (SIGFPE) != 's')
285 sigaction (SIGFPE, &act, NULL);
286 if (__gnat_get_interrupt_state (SIGILL) != 's')
287 sigaction (SIGILL, &act, NULL);
288 if (__gnat_get_interrupt_state (SIGSEGV) != 's')
289 sigaction (SIGSEGV, &act, NULL);
290 if (__gnat_get_interrupt_state (SIGBUS) != 's')
291 sigaction (SIGBUS, &act, NULL);
292
293 __gnat_handler_installed = 1;
294 }
295
296 /*****************/
297 /* HP-UX section */
298 /*****************/
299
300 #elif defined (__hpux__)
301
302 #include <signal.h>
303 #include <sys/ucontext.h>
304
305 #if defined (IN_RTS) && defined (__ia64__)
306
307 #include <sys/uc_access.h>
308
309 #define HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
310
311 void
312 __gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED, void *ucontext)
313 {
314 ucontext_t *uc = (ucontext_t *) ucontext;
315 uint64_t ip;
316
317 /* Adjust on itanium, as GetIPInfo is not supported. */
318 __uc_get_ip (uc, &ip);
319 __uc_set_ip (uc, ip + 1);
320 }
321 #endif /* IN_RTS && __ia64__ */
322
323 /* Tasking and Non-tasking signal handler. Map SIGnal to Ada exception
324 propagation after the required low level adjustments. */
325
326 static void
327 __gnat_error_handler (int sig, siginfo_t *si ATTRIBUTE_UNUSED, void *ucontext)
328 {
329 struct Exception_Data *exception;
330 const char *msg;
331
332 __gnat_adjust_context_for_raise (sig, ucontext);
333
334 switch (sig)
335 {
336 case SIGSEGV:
337 /* FIXME: we need to detect the case of a *real* SIGSEGV. */
338 exception = &storage_error;
339 msg = "stack overflow or erroneous memory access";
340 break;
341
342 case SIGBUS:
343 exception = &constraint_error;
344 msg = "SIGBUS";
345 break;
346
347 case SIGFPE:
348 exception = &constraint_error;
349 msg = "SIGFPE";
350 break;
351
352 default:
353 exception = &program_error;
354 msg = "unhandled signal";
355 }
356
357 Raise_From_Signal_Handler (exception, msg);
358 }
359
360 /* This must be in keeping with System.OS_Interface.Alternate_Stack_Size. */
361 #if defined (__hppa__)
362 char __gnat_alternate_stack[16 * 1024]; /* 2 * SIGSTKSZ */
363 #else
364 char __gnat_alternate_stack[128 * 1024]; /* MINSIGSTKSZ */
365 #endif
366
367 void
368 __gnat_install_handler (void)
369 {
370 struct sigaction act;
371
372 /* Set up signal handler to map synchronous signals to appropriate
373 exceptions. Make sure that the handler isn't interrupted by another
374 signal that might cause a scheduling event! Also setup an alternate
375 stack region for the handler execution so that stack overflows can be
376 handled properly, avoiding a SEGV generation from stack usage by the
377 handler itself. */
378
379 stack_t stack;
380 stack.ss_sp = __gnat_alternate_stack;
381 stack.ss_size = sizeof (__gnat_alternate_stack);
382 stack.ss_flags = 0;
383 sigaltstack (&stack, NULL);
384
385 act.sa_sigaction = __gnat_error_handler;
386 act.sa_flags = SA_NODEFER | SA_RESTART | SA_SIGINFO;
387 sigemptyset (&act.sa_mask);
388
389 /* Do not install handlers if interrupt state is "System". */
390 if (__gnat_get_interrupt_state (SIGABRT) != 's')
391 sigaction (SIGABRT, &act, NULL);
392 if (__gnat_get_interrupt_state (SIGFPE) != 's')
393 sigaction (SIGFPE, &act, NULL);
394 if (__gnat_get_interrupt_state (SIGILL) != 's')
395 sigaction (SIGILL, &act, NULL);
396 if (__gnat_get_interrupt_state (SIGBUS) != 's')
397 sigaction (SIGBUS, &act, NULL);
398 act.sa_flags |= SA_ONSTACK;
399 if (__gnat_get_interrupt_state (SIGSEGV) != 's')
400 sigaction (SIGSEGV, &act, NULL);
401
402 __gnat_handler_installed = 1;
403 }
404
405 /*********************/
406 /* GNU/Linux Section */
407 /*********************/
408
409 #elif defined (__linux__)
410
411 #include <signal.h>
412
413 #define __USE_GNU 1 /* required to get REG_EIP/RIP from glibc's ucontext.h */
414 #include <sys/ucontext.h>
415
416 /* GNU/Linux, which uses glibc, does not define NULL in included
417 header files. */
418
419 #if !defined (NULL)
420 #define NULL ((void *) 0)
421 #endif
422
423 #if defined (MaRTE)
424
425 /* MaRTE OS provides its own version of sigaction, sigfillset, and
426 sigemptyset (overriding these symbol names). We want to make sure that
427 the versions provided by the underlying C library are used here (these
428 versions are renamed by MaRTE to linux_sigaction, fake_linux_sigfillset,
429 and fake_linux_sigemptyset, respectively). The MaRTE library will not
430 always be present (it will not be linked if no tasking constructs are
431 used), so we use the weak symbol mechanism to point always to the symbols
432 defined within the C library. */
433
434 #pragma weak linux_sigaction
435 int linux_sigaction (int signum, const struct sigaction *act,
436 struct sigaction *oldact)
437 {
438 return sigaction (signum, act, oldact);
439 }
440 #define sigaction(signum, act, oldact) linux_sigaction (signum, act, oldact)
441
442 #pragma weak fake_linux_sigfillset
443 void fake_linux_sigfillset (sigset_t *set)
444 {
445 sigfillset (set);
446 }
447 #define sigfillset(set) fake_linux_sigfillset (set)
448
449 #pragma weak fake_linux_sigemptyset
450 void fake_linux_sigemptyset (sigset_t *set)
451 {
452 sigemptyset (set);
453 }
454 #define sigemptyset(set) fake_linux_sigemptyset (set)
455
456 #endif
457
458 #if defined (__i386__) || defined (__x86_64__) || defined (__ia64__) \
459 || defined (__ARMEL__)
460
461 #define HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
462
463 void
464 __gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED, void *ucontext)
465 {
466 mcontext_t *mcontext = &((ucontext_t *) ucontext)->uc_mcontext;
467
468 /* On the i386 and x86-64 architectures, stack checking is performed by
469 means of probes with moving stack pointer, that is to say the probed
470 address is always the value of the stack pointer. Upon hitting the
471 guard page, the stack pointer therefore points to an inaccessible
472 address and an alternate signal stack is needed to run the handler.
473 But there is an additional twist: on these architectures, the EH
474 return code writes the address of the handler at the target CFA's
475 value on the stack before doing the jump. As a consequence, if
476 there is an active handler in the frame whose stack has overflowed,
477 the stack pointer must nevertheless point to an accessible address
478 by the time the EH return is executed.
479
480 We therefore adjust the saved value of the stack pointer by the size
481 of one page + a small dope of 4 words, in order to make sure that it
482 points to an accessible address in case it's used as the target CFA.
483 The stack checking code guarantees that this address is unused by the
484 time this happens. */
485
486 #if defined (__i386__)
487 unsigned long *pc = (unsigned long *)mcontext->gregs[REG_EIP];
488 /* The pattern is "orl $0x0,(%esp)" for a probe in 32-bit mode. */
489 if (signo == SIGSEGV && pc && *pc == 0x00240c83)
490 mcontext->gregs[REG_ESP] += 4096 + 4 * sizeof (unsigned long);
491 #elif defined (__x86_64__)
492 unsigned long long *pc = (unsigned long long *)mcontext->gregs[REG_RIP];
493 if (signo == SIGSEGV && pc
494 /* The pattern is "orq $0x0,(%rsp)" for a probe in 64-bit mode. */
495 && ((*pc & 0xffffffffffLL) == 0x00240c8348LL
496 /* The pattern may also be "orl $0x0,(%esp)" for a probe in
497 x32 mode. */
498 || (*pc & 0xffffffffLL) == 0x00240c83LL))
499 mcontext->gregs[REG_RSP] += 4096 + 4 * sizeof (unsigned long);
500 #elif defined (__ia64__)
501 /* ??? The IA-64 unwinder doesn't compensate for signals. */
502 mcontext->sc_ip++;
503 #elif defined (__ARMEL__)
504 /* ARM Bump has to be an even number because of odd/even architecture. */
505 mcontext->arm_pc+=2;
506 #endif
507 }
508
509 #endif
510
511 static void
512 __gnat_error_handler (int sig, siginfo_t *si ATTRIBUTE_UNUSED, void *ucontext)
513 {
514 struct Exception_Data *exception;
515 const char *msg;
516
517 /* Adjusting is required for every fault context, so adjust for this one
518 now, before we possibly trigger a recursive fault below. */
519 __gnat_adjust_context_for_raise (sig, ucontext);
520
521 switch (sig)
522 {
523 case SIGSEGV:
524 /* Here we would like a discrimination test to see whether the page
525 before the faulting address is accessible. Unfortunately, Linux
526 seems to have no way of giving us the faulting address.
527
528 In old versions of init.c, we had a test of the page before the
529 stack pointer:
530
531 ((volatile char *)
532 ((long) si->esp_at_signal & - getpagesize ()))[getpagesize ()];
533
534 but that's wrong since it tests the stack pointer location and the
535 stack probing code may not move it until all probes succeed.
536
537 For now we simply do not attempt any discrimination at all. Note
538 that this is quite acceptable, since a "real" SIGSEGV can only
539 occur as the result of an erroneous program. */
540 exception = &storage_error;
541 msg = "stack overflow or erroneous memory access";
542 break;
543
544 case SIGBUS:
545 exception = &storage_error;
546 msg = "SIGBUS: possible stack overflow";
547 break;
548
549 case SIGFPE:
550 exception = &constraint_error;
551 msg = "SIGFPE";
552 break;
553
554 default:
555 exception = &program_error;
556 msg = "unhandled signal";
557 }
558
559 Raise_From_Signal_Handler (exception, msg);
560 }
561
562 #ifndef __ia64__
563 #define HAVE_GNAT_ALTERNATE_STACK 1
564 /* This must be in keeping with System.OS_Interface.Alternate_Stack_Size.
565 It must be larger than MINSIGSTKSZ and hopefully near 2 * SIGSTKSZ. */
566 # if 16 * 1024 < MINSIGSTKSZ
567 # error "__gnat_alternate_stack too small"
568 # endif
569 char __gnat_alternate_stack[16 * 1024];
570 #endif
571
572 #ifdef __XENO__
573 #include <sys/mman.h>
574 #include <native/task.h>
575
576 RT_TASK main_task;
577 #endif
578
579 void
580 __gnat_install_handler (void)
581 {
582 struct sigaction act;
583
584 #ifdef __XENO__
585 int prio;
586
587 if (__gl_main_priority == -1)
588 prio = 49;
589 else
590 prio = __gl_main_priority;
591
592 /* Avoid memory swapping for this program */
593
594 mlockall (MCL_CURRENT|MCL_FUTURE);
595
596 /* Turn the current Linux task into a native Xenomai task */
597
598 rt_task_shadow (&main_task, "environment_task", prio, T_FPU);
599 #endif
600
601 /* Set up signal handler to map synchronous signals to appropriate
602 exceptions. Make sure that the handler isn't interrupted by another
603 signal that might cause a scheduling event! Also setup an alternate
604 stack region for the handler execution so that stack overflows can be
605 handled properly, avoiding a SEGV generation from stack usage by the
606 handler itself. */
607
608 act.sa_sigaction = __gnat_error_handler;
609 act.sa_flags = SA_NODEFER | SA_RESTART | SA_SIGINFO;
610 sigemptyset (&act.sa_mask);
611
612 /* Do not install handlers if interrupt state is "System". */
613 if (__gnat_get_interrupt_state (SIGABRT) != 's')
614 sigaction (SIGABRT, &act, NULL);
615 if (__gnat_get_interrupt_state (SIGFPE) != 's')
616 sigaction (SIGFPE, &act, NULL);
617 if (__gnat_get_interrupt_state (SIGILL) != 's')
618 sigaction (SIGILL, &act, NULL);
619 if (__gnat_get_interrupt_state (SIGBUS) != 's')
620 sigaction (SIGBUS, &act, NULL);
621 if (__gnat_get_interrupt_state (SIGSEGV) != 's')
622 {
623 #ifdef HAVE_GNAT_ALTERNATE_STACK
624 /* Setup an alternate stack region for the handler execution so that
625 stack overflows can be handled properly, avoiding a SEGV generation
626 from stack usage by the handler itself. */
627 stack_t stack;
628
629 stack.ss_sp = __gnat_alternate_stack;
630 stack.ss_size = sizeof (__gnat_alternate_stack);
631 stack.ss_flags = 0;
632 sigaltstack (&stack, NULL);
633
634 act.sa_flags |= SA_ONSTACK;
635 #endif
636 sigaction (SIGSEGV, &act, NULL);
637 }
638
639 __gnat_handler_installed = 1;
640 }
641
642 /*******************/
643 /* LynxOS Section */
644 /*******************/
645
646 #elif defined (__Lynx__)
647
648 #include <signal.h>
649 #include <unistd.h>
650
651 static void
652 __gnat_error_handler (int sig)
653 {
654 struct Exception_Data *exception;
655 const char *msg;
656
657 switch(sig)
658 {
659 case SIGFPE:
660 exception = &constraint_error;
661 msg = "SIGFPE";
662 break;
663 case SIGILL:
664 exception = &constraint_error;
665 msg = "SIGILL";
666 break;
667 case SIGSEGV:
668 exception = &storage_error;
669 msg = "stack overflow or erroneous memory access";
670 break;
671 case SIGBUS:
672 exception = &constraint_error;
673 msg = "SIGBUS";
674 break;
675 default:
676 exception = &program_error;
677 msg = "unhandled signal";
678 }
679
680 Raise_From_Signal_Handler (exception, msg);
681 }
682
683 void
684 __gnat_install_handler (void)
685 {
686 struct sigaction act;
687
688 act.sa_handler = __gnat_error_handler;
689 act.sa_flags = 0x0;
690 sigemptyset (&act.sa_mask);
691
692 /* Do not install handlers if interrupt state is "System". */
693 if (__gnat_get_interrupt_state (SIGFPE) != 's')
694 sigaction (SIGFPE, &act, NULL);
695 if (__gnat_get_interrupt_state (SIGILL) != 's')
696 sigaction (SIGILL, &act, NULL);
697 if (__gnat_get_interrupt_state (SIGSEGV) != 's')
698 sigaction (SIGSEGV, &act, NULL);
699 if (__gnat_get_interrupt_state (SIGBUS) != 's')
700 sigaction (SIGBUS, &act, NULL);
701
702 __gnat_handler_installed = 1;
703 }
704
705 /*******************/
706 /* Solaris Section */
707 /*******************/
708
709 #elif defined (__sun__) && !defined (__vxworks)
710
711 #include <signal.h>
712 #include <siginfo.h>
713 #include <sys/ucontext.h>
714 #include <sys/regset.h>
715
716 static void
717 __gnat_error_handler (int sig, siginfo_t *si, void *ucontext ATTRIBUTE_UNUSED)
718 {
719 struct Exception_Data *exception;
720 static int recurse = 0;
721 const char *msg;
722
723 switch (sig)
724 {
725 case SIGSEGV:
726 /* If the problem was permissions, this is a constraint error.
727 Likewise if the failing address isn't maximally aligned or if
728 we've recursed.
729
730 ??? Using a static variable here isn't task-safe, but it's
731 much too hard to do anything else and we're just determining
732 which exception to raise. */
733 if (si->si_code == SEGV_ACCERR
734 || (long) si->si_addr == 0
735 || (((long) si->si_addr) & 3) != 0
736 || recurse)
737 {
738 exception = &constraint_error;
739 msg = "SIGSEGV";
740 }
741 else
742 {
743 /* See if the page before the faulting page is accessible. Do that
744 by trying to access it. We'd like to simply try to access
745 4096 + the faulting address, but it's not guaranteed to be
746 the actual address, just to be on the same page. */
747 recurse++;
748 ((volatile char *)
749 ((long) si->si_addr & - getpagesize ()))[getpagesize ()];
750 exception = &storage_error;
751 msg = "stack overflow or erroneous memory access";
752 }
753 break;
754
755 case SIGBUS:
756 exception = &program_error;
757 msg = "SIGBUS";
758 break;
759
760 case SIGFPE:
761 exception = &constraint_error;
762 msg = "SIGFPE";
763 break;
764
765 default:
766 exception = &program_error;
767 msg = "unhandled signal";
768 }
769
770 recurse = 0;
771 Raise_From_Signal_Handler (exception, msg);
772 }
773
774 void
775 __gnat_install_handler (void)
776 {
777 struct sigaction act;
778
779 /* Set up signal handler to map synchronous signals to appropriate
780 exceptions. Make sure that the handler isn't interrupted by another
781 signal that might cause a scheduling event! */
782
783 act.sa_sigaction = __gnat_error_handler;
784 act.sa_flags = SA_NODEFER | SA_RESTART | SA_SIGINFO;
785 sigemptyset (&act.sa_mask);
786
787 /* Do not install handlers if interrupt state is "System". */
788 if (__gnat_get_interrupt_state (SIGABRT) != 's')
789 sigaction (SIGABRT, &act, NULL);
790 if (__gnat_get_interrupt_state (SIGFPE) != 's')
791 sigaction (SIGFPE, &act, NULL);
792 if (__gnat_get_interrupt_state (SIGSEGV) != 's')
793 sigaction (SIGSEGV, &act, NULL);
794 if (__gnat_get_interrupt_state (SIGBUS) != 's')
795 sigaction (SIGBUS, &act, NULL);
796
797 __gnat_handler_installed = 1;
798 }
799
800 /***************/
801 /* VMS Section */
802 /***************/
803
804 #elif defined (VMS)
805
806 /* Routine called from binder to override default feature values. */
807 void __gnat_set_features (void);
808 int __gnat_features_set = 0;
809 void (*__gnat_ctrl_c_handler) (void) = 0;
810
811 #ifdef __IA64
812 #define lib_get_curr_invo_context LIB$I64_GET_CURR_INVO_CONTEXT
813 #define lib_get_prev_invo_context LIB$I64_GET_PREV_INVO_CONTEXT
814 #define lib_get_invo_handle LIB$I64_GET_INVO_HANDLE
815 #else
816 #define lib_get_curr_invo_context LIB$GET_CURR_INVO_CONTEXT
817 #define lib_get_prev_invo_context LIB$GET_PREV_INVO_CONTEXT
818 #define lib_get_invo_handle LIB$GET_INVO_HANDLE
819 #endif
820
821 /* Masks for facility identification. */
822 #define FAC_MASK 0x0fff0000
823 #define DECADA_M_FACILITY 0x00310000
824
825 /* Define macro symbols for the VMS conditions that become Ada exceptions.
826 It would be better to just include <ssdef.h> */
827
828 #define SS$_CONTINUE 1
829 #define SS$_ACCVIO 12
830 #define SS$_HPARITH 1284
831 #define SS$_INTDIV 1156
832 #define SS$_STKOVF 1364
833 #define SS$_CONTROLC 1617
834 #define SS$_RESIGNAL 2328
835
836 #define MTH$_FLOOVEMAT 1475268 /* Some ACVC_21 CXA tests */
837
838 /* The following codes must be resignalled, and not handled here. */
839
840 /* These codes are in standard message libraries. */
841 extern int C$_SIGKILL;
842 extern int C$_SIGINT;
843 extern int SS$_DEBUG;
844 extern int LIB$_KEYNOTFOU;
845 extern int LIB$_ACTIMAGE;
846
847 /* These codes are non standard, which is to say the author is
848 not sure if they are defined in the standard message libraries
849 so keep them as macros for now. */
850 #define RDB$_STREAM_EOF 20480426
851 #define FDL$_UNPRIKW 11829410
852 #define CMA$_EXIT_THREAD 4227492
853
854 struct cond_sigargs
855 {
856 unsigned int sigarg;
857 unsigned int sigargval;
858 };
859
860 struct cond_subtests
861 {
862 unsigned int num;
863 const struct cond_sigargs sigargs[];
864 };
865
866 struct cond_except
867 {
868 unsigned int cond;
869 const struct Exception_Data *except;
870 unsigned int needs_adjust; /* 1 = adjust PC, 0 = no adjust */
871 const struct cond_subtests *subtests;
872 };
873
874 struct descriptor_s
875 {
876 unsigned short len, mbz;
877 __char_ptr32 adr;
878 };
879
880 /* Conditions that don't have an Ada exception counterpart must raise
881 Non_Ada_Error. Since this is defined in s-auxdec, it should only be
882 referenced by user programs, not the compiler or tools. Hence the
883 #ifdef IN_RTS. */
884
885 #ifdef IN_RTS
886
887 #define Status_Error ada__io_exceptions__status_error
888 extern struct Exception_Data Status_Error;
889
890 #define Mode_Error ada__io_exceptions__mode_error
891 extern struct Exception_Data Mode_Error;
892
893 #define Name_Error ada__io_exceptions__name_error
894 extern struct Exception_Data Name_Error;
895
896 #define Use_Error ada__io_exceptions__use_error
897 extern struct Exception_Data Use_Error;
898
899 #define Device_Error ada__io_exceptions__device_error
900 extern struct Exception_Data Device_Error;
901
902 #define End_Error ada__io_exceptions__end_error
903 extern struct Exception_Data End_Error;
904
905 #define Data_Error ada__io_exceptions__data_error
906 extern struct Exception_Data Data_Error;
907
908 #define Layout_Error ada__io_exceptions__layout_error
909 extern struct Exception_Data Layout_Error;
910
911 #define Non_Ada_Error system__aux_dec__non_ada_error
912 extern struct Exception_Data Non_Ada_Error;
913
914 #define Coded_Exception system__vms_exception_table__coded_exception
915 extern struct Exception_Data *Coded_Exception (void *);
916
917 #define Base_Code_In system__vms_exception_table__base_code_in
918 extern void *Base_Code_In (void *);
919
920 /* DEC Ada exceptions are not defined in a header file, so they
921 must be declared. */
922
923 #define ADA$_ALREADY_OPEN 0x0031a594
924 #define ADA$_CONSTRAINT_ERRO 0x00318324
925 #define ADA$_DATA_ERROR 0x003192c4
926 #define ADA$_DEVICE_ERROR 0x003195e4
927 #define ADA$_END_ERROR 0x00319904
928 #define ADA$_FAC_MODE_MISMAT 0x0031a8b3
929 #define ADA$_IOSYSFAILED 0x0031af04
930 #define ADA$_KEYSIZERR 0x0031aa3c
931 #define ADA$_KEY_MISMATCH 0x0031a8e3
932 #define ADA$_LAYOUT_ERROR 0x00319c24
933 #define ADA$_LINEXCMRS 0x0031a8f3
934 #define ADA$_MAXLINEXC 0x0031a8eb
935 #define ADA$_MODE_ERROR 0x00319f44
936 #define ADA$_MRN_MISMATCH 0x0031a8db
937 #define ADA$_MRS_MISMATCH 0x0031a8d3
938 #define ADA$_NAME_ERROR 0x0031a264
939 #define ADA$_NOT_OPEN 0x0031a58c
940 #define ADA$_ORG_MISMATCH 0x0031a8bb
941 #define ADA$_PROGRAM_ERROR 0x00318964
942 #define ADA$_RAT_MISMATCH 0x0031a8cb
943 #define ADA$_RFM_MISMATCH 0x0031a8c3
944 #define ADA$_STAOVF 0x00318cac
945 #define ADA$_STATUS_ERROR 0x0031a584
946 #define ADA$_STORAGE_ERROR 0x00318c84
947 #define ADA$_UNSUPPORTED 0x0031a8ab
948 #define ADA$_USE_ERROR 0x0031a8a4
949
950 /* DEC Ada specific conditions. */
951 static const struct cond_except dec_ada_cond_except_table [] =
952 {
953 {ADA$_PROGRAM_ERROR, &program_error, 0, 0},
954 {ADA$_USE_ERROR, &Use_Error, 0, 0},
955 {ADA$_KEYSIZERR, &program_error, 0, 0},
956 {ADA$_STAOVF, &storage_error, 0, 0},
957 {ADA$_CONSTRAINT_ERRO, &constraint_error, 0, 0},
958 {ADA$_IOSYSFAILED, &Device_Error, 0, 0},
959 {ADA$_LAYOUT_ERROR, &Layout_Error, 0, 0},
960 {ADA$_STORAGE_ERROR, &storage_error, 0, 0},
961 {ADA$_DATA_ERROR, &Data_Error, 0, 0},
962 {ADA$_DEVICE_ERROR, &Device_Error, 0, 0},
963 {ADA$_END_ERROR, &End_Error, 0, 0},
964 {ADA$_MODE_ERROR, &Mode_Error, 0, 0},
965 {ADA$_NAME_ERROR, &Name_Error, 0, 0},
966 {ADA$_STATUS_ERROR, &Status_Error, 0, 0},
967 {ADA$_NOT_OPEN, &Use_Error, 0, 0},
968 {ADA$_ALREADY_OPEN, &Use_Error, 0, 0},
969 {ADA$_USE_ERROR, &Use_Error, 0, 0},
970 {ADA$_UNSUPPORTED, &Use_Error, 0, 0},
971 {ADA$_FAC_MODE_MISMAT, &Use_Error, 0, 0},
972 {ADA$_ORG_MISMATCH, &Use_Error, 0, 0},
973 {ADA$_RFM_MISMATCH, &Use_Error, 0, 0},
974 {ADA$_RAT_MISMATCH, &Use_Error, 0, 0},
975 {ADA$_MRS_MISMATCH, &Use_Error, 0, 0},
976 {ADA$_MRN_MISMATCH, &Use_Error, 0, 0},
977 {ADA$_KEY_MISMATCH, &Use_Error, 0, 0},
978 {ADA$_MAXLINEXC, &constraint_error, 0, 0},
979 {ADA$_LINEXCMRS, &constraint_error, 0, 0},
980
981 #if 0
982 /* Already handled by a pragma Import_Exception
983 in Aux_IO_Exceptions */
984 {ADA$_LOCK_ERROR, &Lock_Error, 0, 0},
985 {ADA$_EXISTENCE_ERROR, &Existence_Error, 0, 0},
986 {ADA$_KEY_ERROR, &Key_Error, 0, 0},
987 #endif
988
989 {0, 0, 0, 0}
990 };
991
992 #endif /* IN_RTS */
993
994 /* Non-DEC Ada specific conditions that map to Ada exceptions. */
995
996 /* Subtest for ACCVIO Constraint_Error, kept for compatibility,
997 in hindsight should have just made ACCVIO == Storage_Error. */
998 #define ACCVIO_VIRTUAL_ADDR 3
999 static const struct cond_subtests accvio_c_e =
1000 {1, /* number of subtests below */
1001 {
1002 { ACCVIO_VIRTUAL_ADDR, 0 }
1003 }
1004 };
1005
1006 /* Macro flag to adjust PC which gets off by one for some conditions,
1007 not sure if this is reliably true, PC could be off by more for
1008 HPARITH for example, unless a trapb is inserted. */
1009 #define NEEDS_ADJUST 1
1010
1011 static const struct cond_except system_cond_except_table [] =
1012 {
1013 {MTH$_FLOOVEMAT, &constraint_error, 0, 0},
1014 {SS$_INTDIV, &constraint_error, 0, 0},
1015 {SS$_HPARITH, &constraint_error, NEEDS_ADJUST, 0},
1016 {SS$_ACCVIO, &constraint_error, NEEDS_ADJUST, &accvio_c_e},
1017 {SS$_ACCVIO, &storage_error, NEEDS_ADJUST, 0},
1018 {SS$_STKOVF, &storage_error, NEEDS_ADJUST, 0},
1019 {0, 0, 0, 0}
1020 };
1021
1022 /* To deal with VMS conditions and their mapping to Ada exceptions,
1023 the __gnat_error_handler routine below is installed as an exception
1024 vector having precedence over DEC frame handlers. Some conditions
1025 still need to be handled by such handlers, however, in which case
1026 __gnat_error_handler needs to return SS$_RESIGNAL. Consider for
1027 instance the use of a third party library compiled with DECAda and
1028 performing its own exception handling internally.
1029
1030 To allow some user-level flexibility, which conditions should be
1031 resignaled is controlled by a predicate function, provided with the
1032 condition value and returning a boolean indication stating whether
1033 this condition should be resignaled or not.
1034
1035 That predicate function is called indirectly, via a function pointer,
1036 by __gnat_error_handler, and changing that pointer is allowed to the
1037 user code by way of the __gnat_set_resignal_predicate interface.
1038
1039 The user level function may then implement what it likes, including
1040 for instance the maintenance of a dynamic data structure if the set
1041 of to be resignalled conditions has to change over the program's
1042 lifetime.
1043
1044 ??? This is not a perfect solution to deal with the possible
1045 interactions between the GNAT and the DECAda exception handling
1046 models and better (more general) schemes are studied. This is so
1047 just provided as a convenient workaround in the meantime, and
1048 should be use with caution since the implementation has been kept
1049 very simple. */
1050
1051 typedef int resignal_predicate (int code);
1052
1053 static const int * const cond_resignal_table [] =
1054 {
1055 &C$_SIGKILL,
1056 (int *)CMA$_EXIT_THREAD,
1057 &SS$_DEBUG,
1058 &LIB$_KEYNOTFOU,
1059 &LIB$_ACTIMAGE,
1060 (int *) RDB$_STREAM_EOF,
1061 (int *) FDL$_UNPRIKW,
1062 0
1063 };
1064
1065 static const int facility_resignal_table [] =
1066 {
1067 0x1380000, /* RDB */
1068 0x2220000, /* SQL */
1069 0
1070 };
1071
1072 /* Default GNAT predicate for resignaling conditions. */
1073
1074 static int
1075 __gnat_default_resignal_p (int code)
1076 {
1077 int i, iexcept;
1078
1079 for (i = 0; facility_resignal_table [i]; i++)
1080 if ((code & FAC_MASK) == facility_resignal_table [i])
1081 return 1;
1082
1083 for (i = 0, iexcept = 0;
1084 cond_resignal_table [i]
1085 && !(iexcept = LIB$MATCH_COND (&code, &cond_resignal_table [i]));
1086 i++);
1087
1088 return iexcept;
1089 }
1090
1091 /* Static pointer to predicate that the __gnat_error_handler exception
1092 vector invokes to determine if it should resignal a condition. */
1093
1094 static resignal_predicate *__gnat_resignal_p = __gnat_default_resignal_p;
1095
1096 /* User interface to change the predicate pointer to PREDICATE. Reset to
1097 the default if PREDICATE is null. */
1098
1099 void
1100 __gnat_set_resignal_predicate (resignal_predicate *predicate)
1101 {
1102 if (predicate == NULL)
1103 __gnat_resignal_p = __gnat_default_resignal_p;
1104 else
1105 __gnat_resignal_p = predicate;
1106 }
1107
1108 /* Should match System.Parameters.Default_Exception_Msg_Max_Length. */
1109 #define Default_Exception_Msg_Max_Length 512
1110
1111 /* Action routine for SYS$PUTMSG. There may be multiple
1112 conditions, each with text to be appended to MESSAGE
1113 and separated by line termination. */
1114 static int
1115 copy_msg (struct descriptor_s *msgdesc, char *message)
1116 {
1117 int len = strlen (message);
1118 int copy_len;
1119
1120 /* Check for buffer overflow and skip. */
1121 if (len > 0 && len <= Default_Exception_Msg_Max_Length - 3)
1122 {
1123 strcat (message, "\r\n");
1124 len += 2;
1125 }
1126
1127 /* Check for buffer overflow and truncate if necessary. */
1128 copy_len = (len + msgdesc->len <= Default_Exception_Msg_Max_Length - 1 ?
1129 msgdesc->len :
1130 Default_Exception_Msg_Max_Length - 1 - len);
1131 strncpy (&message [len], msgdesc->adr, copy_len);
1132 message [len + copy_len] = 0;
1133
1134 return 0;
1135 }
1136
1137 /* Scan TABLE for a match for the condition contained in SIGARGS,
1138 and return the entry, or the empty entry if no match found. */
1139 static const struct cond_except *
1140 scan_conditions ( int *sigargs, const struct cond_except *table [])
1141 {
1142 int i;
1143 struct cond_except entry;
1144
1145 /* Scan the exception condition table for a match and fetch
1146 the associated GNAT exception pointer. */
1147 for (i = 0; (*table) [i].cond; i++)
1148 {
1149 unsigned int match = LIB$MATCH_COND (&sigargs [1], &(*table) [i].cond);
1150 const struct cond_subtests *subtests = (*table) [i].subtests;
1151
1152 if (match)
1153 {
1154 if (!subtests)
1155 {
1156 return &(*table) [i];
1157 }
1158 else
1159 {
1160 unsigned int ii;
1161 int num = (*subtests).num;
1162
1163 /* Perform subtests to differentiate exception. */
1164 for (ii = 0; ii < num; ii++)
1165 {
1166 unsigned int arg = (*subtests).sigargs [ii].sigarg;
1167 unsigned int argval = (*subtests).sigargs [ii].sigargval;
1168
1169 if (sigargs [arg] != argval)
1170 {
1171 num = 0;
1172 break;
1173 }
1174 }
1175
1176 /* All subtests passed. */
1177 if (num == (*subtests).num)
1178 return &(*table) [i];
1179 }
1180 }
1181 }
1182
1183 /* No match, return the null terminating entry. */
1184 return &(*table) [i];
1185 }
1186
1187 /* __gnat_handle_vms_condtition is both a frame based handler
1188 for the runtime, and an exception vector for the compiler. */
1189 long
1190 __gnat_handle_vms_condition (int *sigargs, void *mechargs)
1191 {
1192 struct Exception_Data *exception = 0;
1193 unsigned int needs_adjust = 0;
1194 void *base_code;
1195 struct descriptor_s gnat_facility = {4, 0, "GNAT"};
1196 char message [Default_Exception_Msg_Max_Length];
1197
1198 const char *msg = "";
1199
1200 /* Check for conditions to resignal which aren't effected by pragma
1201 Import_Exception. */
1202 if (__gnat_resignal_p (sigargs [1]))
1203 return SS$_RESIGNAL;
1204 #ifndef IN_RTS
1205 /* toplev.c handles this for compiler. */
1206 if (sigargs [1] == SS$_HPARITH)
1207 return SS$_RESIGNAL;
1208 #endif
1209
1210 #ifdef IN_RTS
1211 /* See if it's an imported exception. Beware that registered exceptions
1212 are bound to their base code, with the severity bits masked off. */
1213 base_code = Base_Code_In ((void *) sigargs[1]);
1214 exception = Coded_Exception (base_code);
1215 #endif
1216
1217 if (exception == 0)
1218 #ifdef IN_RTS
1219 {
1220 int i;
1221 struct cond_except cond;
1222 const struct cond_except *cond_table;
1223 const struct cond_except *cond_tables [] = {dec_ada_cond_except_table,
1224 system_cond_except_table,
1225 0};
1226 unsigned int ctrlc = SS$_CONTROLC;
1227 unsigned int *sigint = &C$_SIGINT;
1228 int ctrlc_match = LIB$MATCH_COND (&sigargs [1], &ctrlc);
1229 int sigint_match = LIB$MATCH_COND (&sigargs [1], &sigint);
1230
1231 extern int SYS$DCLAST (void (*astadr)(), unsigned long long astprm,
1232 unsigned int acmode);
1233
1234 /* If SS$_CONTROLC has been imported as an exception, it will take
1235 priority over a Ctrl/C handler. See above. SIGINT has a
1236 different condition value due to it's DECCCRTL roots and it's
1237 the condition that gets raised for a "kill -INT". */
1238 if ((ctrlc_match || sigint_match) && __gnat_ctrl_c_handler)
1239 {
1240 SYS$DCLAST (__gnat_ctrl_c_handler, 0, 0);
1241 return SS$_CONTINUE;
1242 }
1243
1244 i = 0;
1245 while ((cond_table = cond_tables[i++]) && !exception)
1246 {
1247 cond = *scan_conditions (sigargs, &cond_table);
1248 exception = (struct Exception_Data *) cond.except;
1249 }
1250
1251 if (exception)
1252 needs_adjust = cond.needs_adjust;
1253 else
1254 /* User programs expect Non_Ada_Error to be raised if no match,
1255 reference DEC Ada test CXCONDHAN. */
1256 exception = &Non_Ada_Error;
1257 }
1258 #else
1259 {
1260 /* Pretty much everything is just a program error in the compiler */
1261 exception = &program_error;
1262 }
1263 #endif
1264
1265 message[0] = 0;
1266 /* Subtract PC & PSL fields as per ABI for SYS$PUTMSG. */
1267 sigargs[0] -= 2;
1268
1269 extern int SYS$PUTMSG (void *, int (*)(), void *, unsigned long long);
1270
1271 /* If it was a DEC Ada specific condtiion, make it GNAT otherwise
1272 keep the old facility. */
1273 if (sigargs [1] & FAC_MASK == DECADA_M_FACILITY)
1274 SYS$PUTMSG (sigargs, copy_msg, &gnat_facility,
1275 (unsigned long long ) message);
1276 else
1277 SYS$PUTMSG (sigargs, copy_msg, 0,
1278 (unsigned long long ) message);
1279
1280 /* Add back PC & PSL fields as per ABI for SYS$PUTMSG. */
1281 sigargs[0] += 2;
1282 msg = message;
1283
1284 if (needs_adjust)
1285 __gnat_adjust_context_for_raise (sigargs [1], (void *)mechargs);
1286
1287 Raise_From_Signal_Handler (exception, msg);
1288 }
1289
1290 #if defined (IN_RTS) && defined (__IA64)
1291 /* Called only from adasigio.b32. This is a band aid to avoid going
1292 through the VMS signal handling code which results in a 0x8000 per
1293 handled exception memory leak in P2 space (see VMS source listing
1294 sys/lis/exception.lis) due to the allocation of working space that
1295 is expected to be deallocated upon return from the condition handler,
1296 which doesn't return in GNAT compiled code. */
1297 void
1298 GNAT$STOP (int *sigargs)
1299 {
1300 /* Note that there are no mechargs. We rely on the fact that condtions
1301 raised from DEClib I/O do not require an "adjust". Also the count
1302 will be off by 2, since LIB$STOP didn't get a chance to add the
1303 PC and PSL fields, so we bump it so PUTMSG comes out right. */
1304 sigargs [0] += 2;
1305 __gnat_handle_vms_condition (sigargs, 0);
1306 }
1307 #endif
1308
1309 void
1310 __gnat_install_handler (void)
1311 {
1312 long prvhnd ATTRIBUTE_UNUSED;
1313
1314 #if !defined (IN_RTS)
1315 extern int SYS$SETEXV (unsigned int vector, int (*addres)(),
1316 unsigned int accmode, void *(*(prvhnd)));
1317 SYS$SETEXV (1, __gnat_handle_vms_condition, 3, &prvhnd);
1318 #endif
1319
1320 __gnat_handler_installed = 1;
1321 }
1322
1323 /* __gnat_adjust_context_for_raise for Alpha - see comments along with the
1324 default version later in this file. */
1325
1326 #if defined (IN_RTS) && defined (__alpha__)
1327
1328 #include <vms/chfctxdef.h>
1329 #include <vms/chfdef.h>
1330
1331 #define HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
1332
1333 void
1334 __gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED, void *ucontext)
1335 {
1336 if (signo == SS$_HPARITH)
1337 {
1338 /* Sub one to the address of the instruction signaling the condition,
1339 located in the sigargs array. */
1340
1341 CHF$MECH_ARRAY * mechargs = (CHF$MECH_ARRAY *) ucontext;
1342 CHF$SIGNAL_ARRAY * sigargs
1343 = (CHF$SIGNAL_ARRAY *) mechargs->chf$q_mch_sig_addr;
1344
1345 int vcount = sigargs->chf$is_sig_args;
1346 int * pc_slot = & (&sigargs->chf$l_sig_name)[vcount-2];
1347
1348 (*pc_slot)--;
1349 }
1350 }
1351
1352 #endif
1353
1354 /* __gnat_adjust_context_for_raise for ia64. */
1355
1356 #if defined (IN_RTS) && defined (__IA64)
1357
1358 #include <vms/chfctxdef.h>
1359 #include <vms/chfdef.h>
1360
1361 #define HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
1362
1363 typedef unsigned long long u64;
1364
1365 void
1366 __gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED, void *ucontext)
1367 {
1368 /* Add one to the address of the instruction signaling the condition,
1369 located in the 64bits sigargs array. */
1370
1371 CHF$MECH_ARRAY * mechargs = (CHF$MECH_ARRAY *) ucontext;
1372
1373 CHF64$SIGNAL_ARRAY *chfsig64
1374 = (CHF64$SIGNAL_ARRAY *) mechargs->chf$ph_mch_sig64_addr;
1375
1376 u64 * post_sigarray
1377 = (u64 *)chfsig64 + 1 + chfsig64->chf64$l_sig_args;
1378
1379 u64 * ih_pc_loc = post_sigarray - 2;
1380
1381 (*ih_pc_loc) ++;
1382 }
1383
1384 #endif
1385
1386 /* Easier interface for LIB$GET_LOGICAL: put the equivalence of NAME into BUF,
1387 always NUL terminated. In case of error or if the result is longer than
1388 LEN (length of BUF) an empty string is written info BUF. */
1389
1390 static void
1391 __gnat_vms_get_logical (const char *name, char *buf, int len)
1392 {
1393 struct descriptor_s name_desc, result_desc;
1394 int status;
1395 unsigned short rlen;
1396
1397 /* Build the descriptor for NAME. */
1398 name_desc.len = strlen (name);
1399 name_desc.mbz = 0;
1400 name_desc.adr = (char *)name;
1401
1402 /* Build the descriptor for the result. */
1403 result_desc.len = len;
1404 result_desc.mbz = 0;
1405 result_desc.adr = buf;
1406
1407 status = LIB$GET_LOGICAL (&name_desc, &result_desc, &rlen);
1408
1409 if ((status & 1) == 1 && rlen < len)
1410 buf[rlen] = 0;
1411 else
1412 buf[0] = 0;
1413 }
1414
1415 /* Size of a page on ia64 and alpha VMS. */
1416 #define VMS_PAGESIZE 8192
1417
1418 /* User mode. */
1419 #define PSL__C_USER 3
1420
1421 /* No access. */
1422 #define PRT__C_NA 0
1423
1424 /* Descending region. */
1425 #define VA__M_DESCEND 1
1426
1427 /* Get by virtual address. */
1428 #define VA___REGSUM_BY_VA 1
1429
1430 /* Memory region summary. */
1431 struct regsum
1432 {
1433 unsigned long long q_region_id;
1434 unsigned int l_flags;
1435 unsigned int l_region_protection;
1436 void *pq_start_va;
1437 unsigned long long q_region_size;
1438 void *pq_first_free_va;
1439 };
1440
1441 extern int SYS$GET_REGION_INFO (unsigned int, unsigned long long *,
1442 void *, void *, unsigned int,
1443 void *, unsigned int *);
1444 extern int SYS$EXPREG_64 (unsigned long long *, unsigned long long,
1445 unsigned int, unsigned int, void **,
1446 unsigned long long *);
1447 extern int SYS$SETPRT_64 (void *, unsigned long long, unsigned int,
1448 unsigned int, void **, unsigned long long *,
1449 unsigned int *);
1450
1451 /* Add a guard page in the memory region containing ADDR at ADDR +/- SIZE.
1452 (The sign depends on the kind of the memory region). */
1453
1454 static int
1455 __gnat_set_stack_guard_page (void *addr, unsigned long size)
1456 {
1457 int status;
1458 void *ret_va;
1459 unsigned long long ret_len;
1460 unsigned int ret_prot;
1461 void *start_va;
1462 unsigned long long length;
1463 unsigned int retlen;
1464 struct regsum buffer;
1465
1466 /* Get the region for ADDR. */
1467 status = SYS$GET_REGION_INFO
1468 (VA___REGSUM_BY_VA, NULL, addr, NULL, sizeof (buffer), &buffer, &retlen);
1469
1470 if ((status & 1) != 1)
1471 return -1;
1472
1473 /* Extend the region. */
1474 status = SYS$EXPREG_64 (&buffer.q_region_id,
1475 size, 0, 0, &start_va, &length);
1476
1477 if ((status & 1) != 1)
1478 return -1;
1479
1480 /* Create a guard page. */
1481 if (!(buffer.l_flags & VA__M_DESCEND))
1482 start_va = (void *)((unsigned long long)start_va + length - VMS_PAGESIZE);
1483
1484 status = SYS$SETPRT_64 (start_va, VMS_PAGESIZE, PSL__C_USER, PRT__C_NA,
1485 &ret_va, &ret_len, &ret_prot);
1486
1487 if ((status & 1) != 1)
1488 return -1;
1489 return 0;
1490 }
1491
1492 /* Read logicals to limit the stack(s) size. */
1493
1494 static void
1495 __gnat_set_stack_limit (void)
1496 {
1497 #ifdef __ia64__
1498 void *sp;
1499 unsigned long size;
1500 char value[16];
1501 char *e;
1502
1503 /* The main stack. */
1504 __gnat_vms_get_logical ("GNAT_STACK_SIZE", value, sizeof (value));
1505 size = strtoul (value, &e, 0);
1506 if (e > value && *e == 0)
1507 {
1508 asm ("mov %0=sp" : "=r" (sp));
1509 __gnat_set_stack_guard_page (sp, size * 1024);
1510 }
1511
1512 /* The register stack. */
1513 __gnat_vms_get_logical ("GNAT_RBS_SIZE", value, sizeof (value));
1514 size = strtoul (value, &e, 0);
1515 if (e > value && *e == 0)
1516 {
1517 asm ("mov %0=ar.bsp" : "=r" (sp));
1518 __gnat_set_stack_guard_page (sp, size * 1024);
1519 }
1520 #endif
1521 }
1522
1523 #ifdef IN_RTS
1524 extern int SYS$IEEE_SET_FP_CONTROL (void *, void *, void *);
1525 #define K_TRUE 1
1526 #define __int64 long long
1527 #define __NEW_STARLET
1528 #include <vms/ieeedef.h>
1529 #endif
1530
1531 /* Feature logical name and global variable address pair.
1532 If we ever add another feature logical to this list, the
1533 feature struct will need to be enhanced to take into account
1534 possible values for *gl_addr. */
1535 struct feature {
1536 const char *name;
1537 int *gl_addr;
1538 };
1539
1540 /* Default values for GNAT features set by environment or binder. */
1541 int __gl_heap_size = 64;
1542
1543 /* Default float format is 'I' meaning IEEE. If gnatbind detetcts that a
1544 VAX Float format is specified, it will set this global variable to 'V'.
1545 Subsequently __gnat_set_features will test the variable and if set for
1546 VAX Float will call a Starlet function to enable trapping for invalid
1547 operation, drivide by zero, and overflow. This will prevent the VMS runtime
1548 (specifically OTS$CHECK_FP_MODE) from complaining about inconsistent
1549 floating point settings in a mixed language program. Ideally the setting
1550 would be determined at link time based on setttings in the object files,
1551 however the VMS linker seems to take the setting from the first object
1552 in the link, e.g. pcrt0.o which is float representation neutral. */
1553 char __gl_float_format = 'I';
1554
1555 /* Array feature logical names and global variable addresses. */
1556 static const struct feature features[] =
1557 {
1558 {"GNAT$NO_MALLOC_64", &__gl_heap_size},
1559 {0, 0}
1560 };
1561
1562 void
1563 __gnat_set_features (void)
1564 {
1565 int i;
1566 char buff[16];
1567 #ifdef IN_RTS
1568 IEEE clrmsk, setmsk, prvmsk;
1569
1570 clrmsk.ieee$q_flags = 0LL;
1571 setmsk.ieee$q_flags = 0LL;
1572 #endif
1573
1574 /* Loop through features array and test name for enable/disable. */
1575 for (i = 0; features[i].name; i++)
1576 {
1577 __gnat_vms_get_logical (features[i].name, buff, sizeof (buff));
1578
1579 if (strcmp (buff, "ENABLE") == 0
1580 || strcmp (buff, "TRUE") == 0
1581 || strcmp (buff, "1") == 0)
1582 *features[i].gl_addr = 32;
1583 else if (strcmp (buff, "DISABLE") == 0
1584 || strcmp (buff, "FALSE") == 0
1585 || strcmp (buff, "0") == 0)
1586 *features[i].gl_addr = 64;
1587 }
1588
1589 /* Features to artificially limit the stack size. */
1590 __gnat_set_stack_limit ();
1591
1592 #ifdef IN_RTS
1593 if (__gl_float_format == 'V')
1594 {
1595 setmsk.ieee$v_trap_enable_inv = K_TRUE;
1596 setmsk.ieee$v_trap_enable_dze = K_TRUE;
1597 setmsk.ieee$v_trap_enable_ovf = K_TRUE;
1598 SYS$IEEE_SET_FP_CONTROL (&clrmsk, &setmsk, &prvmsk);
1599 }
1600 #endif
1601
1602 __gnat_features_set = 1;
1603 }
1604
1605 /* Return true if the VMS version is 7.x. */
1606
1607 extern unsigned int LIB$GETSYI (int *, ...);
1608
1609 #define SYI$_VERSION 0x1000
1610
1611 int
1612 __gnat_is_vms_v7 (void)
1613 {
1614 struct descriptor_s desc;
1615 char version[8];
1616 int status;
1617 int code = SYI$_VERSION;
1618
1619 desc.len = sizeof (version);
1620 desc.mbz = 0;
1621 desc.adr = version;
1622
1623 status = LIB$GETSYI (&code, 0, &desc);
1624 if ((status & 1) == 1 && version[1] == '7' && version[2] == '.')
1625 return 1;
1626 else
1627 return 0;
1628 }
1629
1630 /*******************/
1631 /* FreeBSD Section */
1632 /*******************/
1633
1634 #elif defined (__FreeBSD__) || defined (__DragonFly__)
1635
1636 #include <signal.h>
1637 #include <sys/ucontext.h>
1638 #include <unistd.h>
1639
1640 static void
1641 __gnat_error_handler (int sig,
1642 siginfo_t *si ATTRIBUTE_UNUSED,
1643 void *ucontext ATTRIBUTE_UNUSED)
1644 {
1645 struct Exception_Data *exception;
1646 const char *msg;
1647
1648 switch (sig)
1649 {
1650 case SIGFPE:
1651 exception = &constraint_error;
1652 msg = "SIGFPE";
1653 break;
1654
1655 case SIGILL:
1656 exception = &constraint_error;
1657 msg = "SIGILL";
1658 break;
1659
1660 case SIGSEGV:
1661 exception = &storage_error;
1662 msg = "stack overflow or erroneous memory access";
1663 break;
1664
1665 case SIGBUS:
1666 exception = &storage_error;
1667 msg = "SIGBUS: possible stack overflow";
1668 break;
1669
1670 default:
1671 exception = &program_error;
1672 msg = "unhandled signal";
1673 }
1674
1675 Raise_From_Signal_Handler (exception, msg);
1676 }
1677
1678 void
1679 __gnat_install_handler (void)
1680 {
1681 struct sigaction act;
1682
1683 /* Set up signal handler to map synchronous signals to appropriate
1684 exceptions. Make sure that the handler isn't interrupted by another
1685 signal that might cause a scheduling event! */
1686
1687 act.sa_sigaction
1688 = (void (*)(int, struct __siginfo *, void*)) __gnat_error_handler;
1689 act.sa_flags = SA_NODEFER | SA_RESTART | SA_SIGINFO;
1690 (void) sigemptyset (&act.sa_mask);
1691
1692 (void) sigaction (SIGILL, &act, NULL);
1693 (void) sigaction (SIGFPE, &act, NULL);
1694 (void) sigaction (SIGSEGV, &act, NULL);
1695 (void) sigaction (SIGBUS, &act, NULL);
1696
1697 __gnat_handler_installed = 1;
1698 }
1699
1700 /*************************************/
1701 /* VxWorks Section (including Vx653) */
1702 /*************************************/
1703
1704 #elif defined(__vxworks)
1705
1706 #include <signal.h>
1707 #include <taskLib.h>
1708 #if defined (__i386__) && !defined (VTHREADS)
1709 #include <sysLib.h>
1710 #endif
1711
1712 #ifndef __RTP__
1713 #include <intLib.h>
1714 #include <iv.h>
1715 #endif
1716
1717 #if ((defined (ARMEL) && (_WRS_VXWORKS_MAJOR == 6)) || defined (__x86_64__)) && !defined(__RTP__)
1718 #define VXWORKS_FORCE_GUARD_PAGE 1
1719 #include <vmLib.h>
1720 extern size_t vxIntStackOverflowSize;
1721 #define INT_OVERFLOW_SIZE vxIntStackOverflowSize
1722 #endif
1723
1724 #ifdef VTHREADS
1725 #include "private/vThreadsP.h"
1726 #endif
1727
1728 #ifndef __RTP__
1729
1730 /* Directly vectored Interrupt routines are not supported when using RTPs. */
1731
1732 extern void * __gnat_inum_to_ivec (int);
1733
1734 /* This is needed by the GNAT run time to handle Vxworks interrupts. */
1735 void *
1736 __gnat_inum_to_ivec (int num)
1737 {
1738 return (void *) INUM_TO_IVEC (num);
1739 }
1740 #endif
1741
1742 #if !defined(__alpha_vxworks) && ((_WRS_VXWORKS_MAJOR != 6) && (_WRS_VXWORKS_MAJOR != 7)) && !defined(__RTP__)
1743
1744 /* getpid is used by s-parint.adb, but is not defined by VxWorks, except
1745 on Alpha VxWorks and VxWorks 6.x (including RTPs). */
1746
1747 extern long getpid (void);
1748
1749 long
1750 getpid (void)
1751 {
1752 return taskIdSelf ();
1753 }
1754 #endif
1755
1756 /* When stack checking is performed by probing a guard page on the stack,
1757 sometimes this guard page is not properly reset on VxWorks. We need to
1758 manually reset it in this case.
1759 This function returns TRUE in case the guard page was hit by the
1760 signal. */
1761 static int
1762 __gnat_reset_guard_page (int sig)
1763 {
1764 /* On ARM VxWorks 6.x and x86_64 VxWorks 7, the guard page is left un-armed
1765 by the kernel after being violated, so subsequent violations aren't
1766 detected.
1767 So we retrieve the address of the guard page from the TCB and compare it
1768 with the page that is violated and re-arm that page if there's a match. */
1769 #if defined (VXWORKS_FORCE_GUARD_PAGE)
1770
1771 /* Ignore signals that are not stack overflow signals */
1772 if (sig != SIGSEGV && sig != SIGBUS && sig != SIGILL) return FALSE;
1773
1774 /* If the target does not support guard pages, INT_OVERFLOW_SIZE will be 0 */
1775 if (INT_OVERFLOW_SIZE == 0) return FALSE;
1776
1777 TASK_ID tid = taskIdSelf ();
1778 WIND_TCB *pTcb = taskTcb (tid);
1779 VIRT_ADDR guardPage = (VIRT_ADDR) pTcb->pStackEnd - INT_OVERFLOW_SIZE;
1780 UINT stateMask = VM_STATE_MASK_VALID;
1781 UINT guardState = VM_STATE_VALID_NOT;
1782
1783 #if (_WRS_VXWORKS_MAJOR >= 7)
1784 stateMask |= MMU_ATTR_SPL_MSK;
1785 guardState |= MMU_ATTR_NO_BLOCK;
1786 #endif
1787
1788 UINT nState;
1789 vmStateGet (NULL, guardPage, &nState);
1790 if ((nState & VM_STATE_MASK_VALID) != VM_STATE_VALID_NOT)
1791 {
1792 /* If the guard page has a valid state, we need to reset to
1793 invalid state here */
1794 vmStateSet (NULL, guardPage, INT_OVERFLOW_SIZE, stateMask, guardState);
1795 return TRUE;
1796 }
1797 #endif /* VXWORKS_FORCE_GUARD_PAGE */
1798 return FALSE;
1799 }
1800
1801 /* VxWorks 653 vThreads expects the field excCnt to be zeroed when a signal is.
1802 handled. The VxWorks version of longjmp does this; GCC's builtin_longjmp
1803 doesn't. */
1804 void
1805 __gnat_clear_exception_count (void)
1806 {
1807 #ifdef VTHREADS
1808 WIND_TCB *currentTask = (WIND_TCB *) taskIdSelf();
1809
1810 currentTask->vThreads.excCnt = 0;
1811 #endif
1812 }
1813
1814 /* Handle different SIGnal to exception mappings in different VxWorks
1815 versions. */
1816 void
1817 __gnat_map_signal (int sig, siginfo_t *si ATTRIBUTE_UNUSED, void *sc)
1818 {
1819 struct Exception_Data *exception;
1820 const char *msg;
1821
1822 switch (sig)
1823 {
1824 case SIGFPE:
1825 exception = &constraint_error;
1826 msg = "SIGFPE";
1827 break;
1828 #ifdef VTHREADS
1829 #ifdef __VXWORKSMILS__
1830 case SIGILL:
1831 exception = &storage_error;
1832 msg = "SIGILL: possible stack overflow";
1833 break;
1834 case SIGSEGV:
1835 exception = &storage_error;
1836 msg = "SIGSEGV";
1837 break;
1838 case SIGBUS:
1839 exception = &program_error;
1840 msg = "SIGBUS";
1841 break;
1842 #else
1843 case SIGILL:
1844 exception = &constraint_error;
1845 msg = "Floating point exception or SIGILL";
1846 break;
1847 case SIGSEGV:
1848 exception = &storage_error;
1849 msg = "SIGSEGV";
1850 break;
1851 case SIGBUS:
1852 exception = &storage_error;
1853 msg = "SIGBUS: possible stack overflow";
1854 break;
1855 #endif
1856 #elif (_WRS_VXWORKS_MAJOR >= 6)
1857 case SIGILL:
1858 exception = &constraint_error;
1859 msg = "SIGILL";
1860 break;
1861 #ifdef __RTP__
1862 /* In RTP mode a SIGSEGV is most likely due to a stack overflow,
1863 since stack checking uses the probing mechanism. */
1864 case SIGSEGV:
1865 exception = &storage_error;
1866 msg = "SIGSEGV: possible stack overflow";
1867 break;
1868 case SIGBUS:
1869 exception = &program_error;
1870 msg = "SIGBUS";
1871 break;
1872 #else
1873 /* VxWorks 6 kernel mode with probing. SIGBUS for guard page hit */
1874 case SIGSEGV:
1875 exception = &storage_error;
1876 msg = "SIGSEGV";
1877 break;
1878 case SIGBUS:
1879 exception = &storage_error;
1880 msg = "SIGBUS: possible stack overflow";
1881 break;
1882 #endif
1883 #else
1884 /* VxWorks 5: a SIGILL is most likely due to a stack overflow,
1885 since stack checking uses the stack limit mechanism. */
1886 case SIGILL:
1887 exception = &storage_error;
1888 msg = "SIGILL: possible stack overflow";
1889 break;
1890 case SIGSEGV:
1891 exception = &storage_error;
1892 msg = "SIGSEGV";
1893 break;
1894 case SIGBUS:
1895 exception = &program_error;
1896 msg = "SIGBUS";
1897 break;
1898 #endif
1899 default:
1900 exception = &program_error;
1901 msg = "unhandled signal";
1902 }
1903
1904 if (__gnat_reset_guard_page (sig))
1905 {
1906 /* Set the exception message: we know for sure that we have a
1907 stack overflow here */
1908 exception = &storage_error;
1909
1910 switch (sig)
1911 {
1912 case SIGSEGV:
1913 msg = "SIGSEGV: stack overflow";
1914 break;
1915 case SIGBUS:
1916 msg = "SIGBUS: stack overflow";
1917 break;
1918 case SIGILL:
1919 msg = "SIGILL: stack overflow";
1920 break;
1921 }
1922 }
1923 __gnat_clear_exception_count ();
1924 Raise_From_Signal_Handler (exception, msg);
1925 }
1926
1927 #if defined (__i386__) && !defined (VTHREADS) && _WRS_VXWORKS_MAJOR < 7
1928
1929 extern void
1930 __gnat_vxsim_error_handler (int sig, siginfo_t *si, void *sc);
1931
1932 static int is_vxsim = 0;
1933 #endif
1934
1935 #if defined (ARMEL) && (_WRS_VXWORKS_MAJOR >= 7)
1936
1937 /* ARM-vx7 case with arm unwinding exceptions */
1938 #define HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
1939
1940 #include <arch/../regs.h>
1941 #ifndef __RTP__
1942 #include <sigLib.h>
1943 #else
1944 #include <signal.h>
1945 #include <regs.h>
1946 #include <ucontext.h>
1947 #endif /* __RTP__ */
1948
1949 void
1950 __gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED,
1951 void *sc ATTRIBUTE_UNUSED)
1952 {
1953 /* In case of ARM exceptions, the registers context have the PC pointing
1954 to the instruction that raised the signal. However the unwinder expects
1955 the instruction to be in the range ]PC,PC+1]. */
1956 uintptr_t *pc_addr;
1957 #ifdef __RTP__
1958 mcontext_t *mcontext = &((ucontext_t *) sc)->uc_mcontext;
1959 pc_addr = (uintptr_t*)&mcontext->regs.pc;
1960 #else
1961 struct sigcontext * sctx = (struct sigcontext *) sc;
1962 pc_addr = (uintptr_t*)&sctx->sc_pregs->pc;
1963 #endif
1964 /* ARM Bump has to be an even number because of odd/even architecture. */
1965 *pc_addr += 2;
1966 }
1967 #endif /* ARMEL && _WRS_VXWORKS_MAJOR >= 7 */
1968
1969 /* Tasking and Non-tasking signal handler. Map SIGnal to Ada exception
1970 propagation after the required low level adjustments. */
1971
1972 static void
1973 __gnat_error_handler (int sig, siginfo_t *si, void *sc)
1974 {
1975 sigset_t mask;
1976
1977 /* VxWorks on e500v2 clears the SPE bit of the MSR when entering CPU
1978 exception state. To allow the handler and exception to work properly
1979 when they contain SPE instructions, we need to set it back before doing
1980 anything else.
1981 This mechanism is only need in kernel mode. */
1982 #if !(defined (__RTP__) || defined (VTHREADS)) && ((CPU == PPCE500V2) || (CPU == PPC85XX))
1983 register unsigned msr;
1984 /* Read the MSR value */
1985 asm volatile ("mfmsr %0" : "=r" (msr));
1986 /* Force the SPE bit if not set. */
1987 if ((msr & 0x02000000) == 0)
1988 {
1989 msr |= 0x02000000;
1990 /* Store to MSR */
1991 asm volatile ("mtmsr %0" : : "r" (msr));
1992 }
1993 #endif
1994
1995 /* VxWorks will always mask out the signal during the signal handler and
1996 will reenable it on a longjmp. GNAT does not generate a longjmp to
1997 return from a signal handler so the signal will still be masked unless
1998 we unmask it. */
1999 sigprocmask (SIG_SETMASK, NULL, &mask);
2000 sigdelset (&mask, sig);
2001 sigprocmask (SIG_SETMASK, &mask, NULL);
2002
2003 #if defined (__ARMEL__) || defined (__PPC__) || defined (__i386__) || defined (__x86_64__)
2004 /* On certain targets, kernel mode, we process signals through a Call Frame
2005 Info trampoline, voiding the need for myriads of fallback_frame_state
2006 variants in the ZCX runtime. We have no simple way to distinguish ZCX
2007 from SJLJ here, so we do this for SJLJ as well even though this is not
2008 necessary. This only incurs a few extra instructions and a tiny
2009 amount of extra stack usage. */
2010
2011 #ifdef HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
2012 /* We need to sometimes to adjust the PC in case of signals so that it
2013 doesn't reference the exception that actually raised the signal but the
2014 instruction before it. */
2015 __gnat_adjust_context_for_raise (sig, sc);
2016 #endif
2017
2018 #if defined (__i386__) && !defined (VTHREADS) && (__WRS_VXWORKS_MAJOR < 7)
2019 /* On x86, the vxsim signal context is subtly different and is processeed
2020 by a handler compiled especially for vxsim.
2021 Vxsim is not supported anymore on our vxworks-7 port. */
2022
2023 if (is_vxsim)
2024 __gnat_vxsim_error_handler (sig, si, sc);
2025 #endif
2026
2027 # include "sigtramp.h"
2028
2029 __gnat_sigtramp (sig, (void *)si, (void *)sc,
2030 (__sigtramphandler_t *)&__gnat_map_signal);
2031
2032 #else
2033 __gnat_map_signal (sig, si, sc);
2034 #endif
2035 }
2036
2037 #if defined(__leon__) && defined(_WRS_KERNEL)
2038 /* For LEON VxWorks we need to install a trap handler for stack overflow */
2039
2040 extern void excEnt (void);
2041 /* VxWorks exception handler entry */
2042
2043 struct trap_entry {
2044 unsigned long inst_first;
2045 unsigned long inst_second;
2046 unsigned long inst_third;
2047 unsigned long inst_fourth;
2048 };
2049 /* Four instructions representing entries in the trap table */
2050
2051 struct trap_entry *trap_0_entry;
2052 /* We will set the location of the entry for software trap 0 in the trap
2053 table. */
2054 #endif
2055
2056 void
2057 __gnat_install_handler (void)
2058 {
2059 struct sigaction act;
2060 char *model ATTRIBUTE_UNUSED;
2061
2062 /* Setup signal handler to map synchronous signals to appropriate
2063 exceptions. Make sure that the handler isn't interrupted by another
2064 signal that might cause a scheduling event! */
2065
2066 act.sa_sigaction = __gnat_error_handler;
2067 act.sa_flags = SA_SIGINFO | SA_ONSTACK;
2068 sigemptyset (&act.sa_mask);
2069
2070 /* For VxWorks, install all signal handlers, since pragma Interrupt_State
2071 applies to vectored hardware interrupts, not signals. */
2072 sigaction (SIGFPE, &act, NULL);
2073 sigaction (SIGILL, &act, NULL);
2074 sigaction (SIGSEGV, &act, NULL);
2075 sigaction (SIGBUS, &act, NULL);
2076
2077 #if defined(__leon__) && defined(_WRS_KERNEL)
2078 /* Specific to the LEON VxWorks kernel run-time library */
2079
2080 /* For stack checking the compiler triggers a software trap 0 (ta 0) in
2081 case of overflow (we use the stack limit mechanism). We need to install
2082 the trap handler here for this software trap (the OS does not handle
2083 it) as if it were a data_access_exception (trap 9). We do the same as
2084 if we put in the trap table a VXSPARC_BAD_TRAP(9). Software trap 0 is
2085 located at vector 0x80, and each entry takes 4 words. */
2086
2087 trap_0_entry = (struct trap_entry *)(intVecBaseGet () + 0x80 * 4);
2088
2089 /* mov 0x9, %l7 */
2090
2091 trap_0_entry->inst_first = 0xae102000 + 9;
2092
2093 /* sethi %hi(excEnt), %l6 */
2094
2095 /* The 22 most significant bits of excEnt are obtained shifting 10 times
2096 to the right. */
2097
2098 trap_0_entry->inst_second = 0x2d000000 + ((unsigned long)excEnt >> 10);
2099
2100 /* jmp %l6+%lo(excEnt) */
2101
2102 /* The 10 least significant bits of excEnt are obtained by masking */
2103
2104 trap_0_entry->inst_third = 0x81c5a000 + ((unsigned long)excEnt & 0x3ff);
2105
2106 /* rd %psr, %l0 */
2107
2108 trap_0_entry->inst_fourth = 0xa1480000;
2109 #endif
2110
2111 #if defined (__i386__) && !defined (VTHREADS) && _WRS_VXWORKS_MAJOR != 7
2112 /* By experiment, found that sysModel () returns the following string
2113 prefix for vxsim when running on Linux and Windows. */
2114 model = sysModel ();
2115 if ((strncmp (model, "Linux", 5) == 0)
2116 || (strncmp (model, "Windows", 7) == 0))
2117 is_vxsim = 1;
2118 #endif
2119
2120 __gnat_handler_installed = 1;
2121 }
2122
2123 #define HAVE_GNAT_INIT_FLOAT
2124
2125 void
2126 __gnat_init_float (void)
2127 {
2128 /* Disable overflow/underflow exceptions on the PPC processor, needed
2129 to get correct Ada semantics. Note that for AE653 vThreads, the HW
2130 overflow settings are an OS configuration issue. The instructions
2131 below have no effect. */
2132 #if defined (_ARCH_PPC) && !defined (_SOFT_FLOAT) && (!defined (VTHREADS) || defined (__VXWORKSMILS__))
2133 #if defined (__SPE__)
2134 {
2135 /* For e500v2, do nothing and leave the responsibility to install the
2136 handler and enable the exceptions to the BSP. */
2137 }
2138 #else
2139 asm ("mtfsb0 25");
2140 asm ("mtfsb0 26");
2141 #endif
2142 #endif
2143
2144 #if defined (__i386__) && !defined (VTHREADS)
2145 /* This is used to properly initialize the FPU on an x86 for each
2146 process thread. Is this needed for x86_64 ??? */
2147 asm ("finit");
2148 #endif
2149
2150 /* Similarly for SPARC64. Achieved by masking bits in the Trap Enable Mask
2151 field of the Floating-point Status Register (see the SPARC Architecture
2152 Manual Version 9, p 48). */
2153 #if defined (sparc64)
2154
2155 #define FSR_TEM_NVM (1 << 27) /* Invalid operand */
2156 #define FSR_TEM_OFM (1 << 26) /* Overflow */
2157 #define FSR_TEM_UFM (1 << 25) /* Underflow */
2158 #define FSR_TEM_DZM (1 << 24) /* Division by Zero */
2159 #define FSR_TEM_NXM (1 << 23) /* Inexact result */
2160 {
2161 unsigned int fsr;
2162
2163 __asm__("st %%fsr, %0" : "=m" (fsr));
2164 fsr &= ~(FSR_TEM_OFM | FSR_TEM_UFM);
2165 __asm__("ld %0, %%fsr" : : "m" (fsr));
2166 }
2167 #endif
2168 }
2169
2170 /* This subprogram is called by System.Task_Primitives.Operations.Enter_Task
2171 (if not null) when a new task is created. It is initialized by
2172 System.Stack_Checking.Operations.Initialize_Stack_Limit.
2173 The use of a hook avoids to drag stack checking subprograms if stack
2174 checking is not used. */
2175 void (*__gnat_set_stack_limit_hook)(void) = (void (*)(void))0;
2176
2177 /******************/
2178 /* NetBSD Section */
2179 /******************/
2180
2181 #elif defined(__NetBSD__)
2182
2183 #include <signal.h>
2184 #include <unistd.h>
2185
2186 static void
2187 __gnat_error_handler (int sig)
2188 {
2189 struct Exception_Data *exception;
2190 const char *msg;
2191
2192 switch(sig)
2193 {
2194 case SIGFPE:
2195 exception = &constraint_error;
2196 msg = "SIGFPE";
2197 break;
2198 case SIGILL:
2199 exception = &constraint_error;
2200 msg = "SIGILL";
2201 break;
2202 case SIGSEGV:
2203 exception = &storage_error;
2204 msg = "stack overflow or erroneous memory access";
2205 break;
2206 case SIGBUS:
2207 exception = &constraint_error;
2208 msg = "SIGBUS";
2209 break;
2210 default:
2211 exception = &program_error;
2212 msg = "unhandled signal";
2213 }
2214
2215 Raise_From_Signal_Handler (exception, msg);
2216 }
2217
2218 void
2219 __gnat_install_handler (void)
2220 {
2221 struct sigaction act;
2222
2223 act.sa_handler = __gnat_error_handler;
2224 act.sa_flags = SA_NODEFER | SA_RESTART;
2225 sigemptyset (&act.sa_mask);
2226
2227 /* Do not install handlers if interrupt state is "System". */
2228 if (__gnat_get_interrupt_state (SIGFPE) != 's')
2229 sigaction (SIGFPE, &act, NULL);
2230 if (__gnat_get_interrupt_state (SIGILL) != 's')
2231 sigaction (SIGILL, &act, NULL);
2232 if (__gnat_get_interrupt_state (SIGSEGV) != 's')
2233 sigaction (SIGSEGV, &act, NULL);
2234 if (__gnat_get_interrupt_state (SIGBUS) != 's')
2235 sigaction (SIGBUS, &act, NULL);
2236
2237 __gnat_handler_installed = 1;
2238 }
2239
2240 /*******************/
2241 /* OpenBSD Section */
2242 /*******************/
2243
2244 #elif defined(__OpenBSD__)
2245
2246 #include <signal.h>
2247 #include <unistd.h>
2248
2249 static void
2250 __gnat_error_handler (int sig)
2251 {
2252 struct Exception_Data *exception;
2253 const char *msg;
2254
2255 switch(sig)
2256 {
2257 case SIGFPE:
2258 exception = &constraint_error;
2259 msg = "SIGFPE";
2260 break;
2261 case SIGILL:
2262 exception = &constraint_error;
2263 msg = "SIGILL";
2264 break;
2265 case SIGSEGV:
2266 exception = &storage_error;
2267 msg = "stack overflow or erroneous memory access";
2268 break;
2269 case SIGBUS:
2270 exception = &constraint_error;
2271 msg = "SIGBUS";
2272 break;
2273 default:
2274 exception = &program_error;
2275 msg = "unhandled signal";
2276 }
2277
2278 Raise_From_Signal_Handler (exception, msg);
2279 }
2280
2281 void
2282 __gnat_install_handler (void)
2283 {
2284 struct sigaction act;
2285
2286 act.sa_handler = __gnat_error_handler;
2287 act.sa_flags = SA_NODEFER | SA_RESTART;
2288 sigemptyset (&act.sa_mask);
2289
2290 /* Do not install handlers if interrupt state is "System" */
2291 if (__gnat_get_interrupt_state (SIGFPE) != 's')
2292 sigaction (SIGFPE, &act, NULL);
2293 if (__gnat_get_interrupt_state (SIGILL) != 's')
2294 sigaction (SIGILL, &act, NULL);
2295 if (__gnat_get_interrupt_state (SIGSEGV) != 's')
2296 sigaction (SIGSEGV, &act, NULL);
2297 if (__gnat_get_interrupt_state (SIGBUS) != 's')
2298 sigaction (SIGBUS, &act, NULL);
2299
2300 __gnat_handler_installed = 1;
2301 }
2302
2303 /******************/
2304 /* Darwin Section */
2305 /******************/
2306
2307 #elif defined(__APPLE__)
2308
2309 #include <TargetConditionals.h>
2310 #include <signal.h>
2311 #include <stdlib.h>
2312 #include <sys/syscall.h>
2313 #include <sys/sysctl.h>
2314
2315 /* This must be in keeping with System.OS_Interface.Alternate_Stack_Size. */
2316 char __gnat_alternate_stack[32 * 1024]; /* 1 * MINSIGSTKSZ */
2317
2318 /* Defined in xnu unix_signal.c.
2319 Tell the kernel to re-use alt stack when delivering a signal. */
2320 #define UC_RESET_ALT_STACK 0x80000000
2321
2322 #if !(defined (__arm__) || defined (__arm64__) || TARGET_IPHONE_SIMULATOR)
2323 #include <mach/mach_vm.h>
2324 #include <mach/mach_init.h>
2325 #include <mach/vm_statistics.h>
2326 #endif
2327
2328 #ifdef __arm64__
2329 #include <sys/ucontext.h>
2330 #include "sigtramp.h"
2331 #endif
2332
2333 /* Return true if ADDR is within a stack guard area. */
2334 static int
2335 __gnat_is_stack_guard (mach_vm_address_t addr)
2336 {
2337 #if !(defined (__arm__) || defined (__arm64__) || TARGET_IPHONE_SIMULATOR)
2338 kern_return_t kret;
2339 vm_region_submap_info_data_64_t info;
2340 mach_vm_address_t start;
2341 mach_vm_size_t size;
2342 natural_t depth;
2343 mach_msg_type_number_t count;
2344
2345 count = VM_REGION_SUBMAP_INFO_COUNT_64;
2346 start = addr;
2347 size = -1;
2348 depth = 9999;
2349 kret = mach_vm_region_recurse (mach_task_self (), &start, &size, &depth,
2350 (vm_region_recurse_info_t) &info, &count);
2351 if (kret == KERN_SUCCESS
2352 && addr >= start && addr < (start + size)
2353 && info.protection == VM_PROT_NONE
2354 && info.user_tag == VM_MEMORY_STACK)
2355 return 1;
2356 return 0;
2357 #else
2358 /* Pagezero for arm. */
2359 return addr >= 4096;
2360 #endif
2361 }
2362
2363 #define HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
2364
2365 #if defined (__x86_64__)
2366 static int
2367 __darwin_major_version (void)
2368 {
2369 static int cache = -1;
2370 if (cache < 0)
2371 {
2372 int mib[2] = {CTL_KERN, KERN_OSRELEASE};
2373 size_t len;
2374
2375 /* Find out how big the buffer needs to be (and set cache to 0
2376 on failure). */
2377 if (sysctl (mib, 2, NULL, &len, NULL, 0) == 0)
2378 {
2379 char release[len];
2380 sysctl (mib, 2, release, &len, NULL, 0);
2381 /* Darwin releases are of the form L.M.N where L is the major
2382 version, so strtol will return L. */
2383 cache = (int) strtol (release, NULL, 10);
2384 }
2385 else
2386 {
2387 cache = 0;
2388 }
2389 }
2390 return cache;
2391 }
2392 #endif
2393
2394 void
2395 __gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED,
2396 void *ucontext ATTRIBUTE_UNUSED)
2397 {
2398 #if defined (__x86_64__)
2399 if (__darwin_major_version () < 12)
2400 {
2401 /* Work around radar #10302855, where the unwinders (libunwind or
2402 libgcc_s depending on the system revision) and the DWARF unwind
2403 data for sigtramp have different ideas about register numbering,
2404 causing rbx and rdx to be transposed. */
2405 ucontext_t *uc = (ucontext_t *)ucontext;
2406 unsigned long t = uc->uc_mcontext->__ss.__rbx;
2407
2408 uc->uc_mcontext->__ss.__rbx = uc->uc_mcontext->__ss.__rdx;
2409 uc->uc_mcontext->__ss.__rdx = t;
2410 }
2411 #elif defined(__arm64__)
2412 /* Even though the CFI is marked as a signal frame, we need this. */
2413 ucontext_t *uc = (ucontext_t *)ucontext;
2414 uc->uc_mcontext->__ss.__pc++;
2415 #endif
2416 }
2417
2418 static void
2419 __gnat_map_signal (int sig, siginfo_t *si, void *mcontext ATTRIBUTE_UNUSED)
2420 {
2421 struct Exception_Data *exception;
2422 const char *msg;
2423
2424 switch (sig)
2425 {
2426 case SIGSEGV:
2427 case SIGBUS:
2428 if (__gnat_is_stack_guard ((unsigned long)si->si_addr))
2429 {
2430 #ifdef __arm64__
2431 /* ??? This is a kludge to make stack checking work. The problem is
2432 that the trampoline doesn't restore LR and, consequently, doesn't
2433 make it possible to unwind past an interrupted frame which hasn"t
2434 saved LR on the stack yet. Therefore, for probes in the prologue
2435 (32-bit probes as opposed to standard 64-bit probes), we make the
2436 unwinder skip the not-yet-established frame altogether. */
2437 mcontext_t mc = (mcontext_t)mcontext;
2438 if (!(*(unsigned int *)(mc->__ss.__pc-1) & ((unsigned int)1 << 30)))
2439 mc->__ss.__pc = mc->__ss.__lr;
2440 #endif
2441 exception = &storage_error;
2442 msg = "stack overflow";
2443 }
2444 else
2445 {
2446 exception = &constraint_error;
2447 msg = "erroneous memory access";
2448 }
2449
2450 /* Reset the use of alt stack, so that the alt stack will be used
2451 for the next signal delivery.
2452 The stack can't be used in case of stack checking. */
2453 syscall (SYS_sigreturn, NULL, UC_RESET_ALT_STACK);
2454 break;
2455
2456 case SIGFPE:
2457 exception = &constraint_error;
2458 msg = "SIGFPE";
2459 break;
2460
2461 default:
2462 exception = &program_error;
2463 msg = "unhandled signal";
2464 }
2465
2466 Raise_From_Signal_Handler (exception, msg);
2467 }
2468
2469 static void
2470 __gnat_error_handler (int sig, siginfo_t *si, void *ucontext)
2471 {
2472 __gnat_adjust_context_for_raise (sig, ucontext);
2473
2474 /* The Darwin libc comes with a signal trampoline, except for ARM64. */
2475 #ifdef __arm64__
2476 __gnat_sigtramp (sig, (void *)si, ucontext,
2477 (__sigtramphandler_t *)&__gnat_map_signal);
2478 #else
2479 __gnat_map_signal (sig, si, ucontext);
2480 #endif
2481 }
2482
2483 void
2484 __gnat_install_handler (void)
2485 {
2486 struct sigaction act;
2487
2488 /* Set up signal handler to map synchronous signals to appropriate
2489 exceptions. Make sure that the handler isn't interrupted by another
2490 signal that might cause a scheduling event! Also setup an alternate
2491 stack region for the handler execution so that stack overflows can be
2492 handled properly, avoiding a SEGV generation from stack usage by the
2493 handler itself (and it is required by Darwin). */
2494
2495 stack_t stack;
2496 stack.ss_sp = __gnat_alternate_stack;
2497 stack.ss_size = sizeof (__gnat_alternate_stack);
2498 stack.ss_flags = 0;
2499 sigaltstack (&stack, NULL);
2500
2501 act.sa_flags = SA_NODEFER | SA_RESTART | SA_SIGINFO;
2502 act.sa_sigaction = __gnat_error_handler;
2503 sigemptyset (&act.sa_mask);
2504
2505 /* Do not install handlers if interrupt state is "System". */
2506 if (__gnat_get_interrupt_state (SIGABRT) != 's')
2507 sigaction (SIGABRT, &act, NULL);
2508 if (__gnat_get_interrupt_state (SIGFPE) != 's')
2509 sigaction (SIGFPE, &act, NULL);
2510 if (__gnat_get_interrupt_state (SIGILL) != 's')
2511 sigaction (SIGILL, &act, NULL);
2512
2513 act.sa_flags |= SA_ONSTACK;
2514 if (__gnat_get_interrupt_state (SIGSEGV) != 's')
2515 sigaction (SIGSEGV, &act, NULL);
2516 if (__gnat_get_interrupt_state (SIGBUS) != 's')
2517 sigaction (SIGBUS, &act, NULL);
2518
2519 __gnat_handler_installed = 1;
2520 }
2521
2522 #elif defined(__ANDROID__)
2523
2524 /*******************/
2525 /* Android Section */
2526 /*******************/
2527
2528 #include <signal.h>
2529 #include <sys/ucontext.h>
2530 #include "sigtramp.h"
2531
2532 #define HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
2533
2534 void
2535 __gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED, void *ucontext)
2536 {
2537 mcontext_t *mcontext = &((ucontext_t *) ucontext)->uc_mcontext;
2538
2539 /* ARM Bump has to be an even number because of odd/even architecture. */
2540 ((mcontext_t *) mcontext)->arm_pc += 2;
2541 }
2542
2543 static void
2544 __gnat_map_signal (int sig,
2545 siginfo_t *si ATTRIBUTE_UNUSED,
2546 void *mcontext ATTRIBUTE_UNUSED)
2547 {
2548 struct Exception_Data *exception;
2549 const char *msg;
2550
2551 switch (sig)
2552 {
2553 case SIGSEGV:
2554 exception = &storage_error;
2555 msg = "stack overflow or erroneous memory access";
2556 break;
2557
2558 case SIGBUS:
2559 exception = &constraint_error;
2560 msg = "SIGBUS";
2561 break;
2562
2563 case SIGFPE:
2564 exception = &constraint_error;
2565 msg = "SIGFPE";
2566 break;
2567
2568 default:
2569 exception = &program_error;
2570 msg = "unhandled signal";
2571 }
2572
2573 Raise_From_Signal_Handler (exception, msg);
2574 }
2575
2576 static void
2577 __gnat_error_handler (int sig, siginfo_t *si, void *ucontext)
2578 {
2579 __gnat_adjust_context_for_raise (sig, ucontext);
2580
2581 __gnat_sigtramp (sig, (void *) si, (void *) ucontext,
2582 (__sigtramphandler_t *)&__gnat_map_signal);
2583 }
2584
2585 /* This must be in keeping with System.OS_Interface.Alternate_Stack_Size. */
2586 char __gnat_alternate_stack[16 * 1024];
2587
2588 void
2589 __gnat_install_handler (void)
2590 {
2591 struct sigaction act;
2592
2593 /* Set up signal handler to map synchronous signals to appropriate
2594 exceptions. Make sure that the handler isn't interrupted by another
2595 signal that might cause a scheduling event! Also setup an alternate
2596 stack region for the handler execution so that stack overflows can be
2597 handled properly, avoiding a SEGV generation from stack usage by the
2598 handler itself. */
2599
2600 stack_t stack;
2601 stack.ss_sp = __gnat_alternate_stack;
2602 stack.ss_size = sizeof (__gnat_alternate_stack);
2603 stack.ss_flags = 0;
2604 sigaltstack (&stack, NULL);
2605
2606 act.sa_sigaction = __gnat_error_handler;
2607 act.sa_flags = SA_NODEFER | SA_RESTART | SA_SIGINFO;
2608 sigemptyset (&act.sa_mask);
2609
2610 sigaction (SIGABRT, &act, NULL);
2611 sigaction (SIGFPE, &act, NULL);
2612 sigaction (SIGILL, &act, NULL);
2613 sigaction (SIGBUS, &act, NULL);
2614 act.sa_flags |= SA_ONSTACK;
2615 sigaction (SIGSEGV, &act, NULL);
2616
2617 __gnat_handler_installed = 1;
2618 }
2619
2620 #else
2621
2622 /* For all other versions of GNAT, the handler does nothing. */
2623
2624 /*******************/
2625 /* Default Section */
2626 /*******************/
2627
2628 void
2629 __gnat_install_handler (void)
2630 {
2631 __gnat_handler_installed = 1;
2632 }
2633
2634 #endif
2635
2636 /*********************/
2637 /* __gnat_init_float */
2638 /*********************/
2639
2640 /* This routine is called as each process thread is created, for possible
2641 initialization of the FP processor. This version is used under INTERIX
2642 and WIN32. */
2643
2644 #if defined (_WIN32) || defined (__INTERIX) \
2645 || defined (__Lynx__) || defined(__NetBSD__) || defined(__FreeBSD__) \
2646 || defined (__OpenBSD__) || defined (__DragonFly__)
2647
2648 #define HAVE_GNAT_INIT_FLOAT
2649
2650 void
2651 __gnat_init_float (void)
2652 {
2653 #if defined (__i386__) || defined (__x86_64__)
2654
2655 /* This is used to properly initialize the FPU on an x86 for each
2656 process thread. */
2657
2658 asm ("finit");
2659
2660 #endif /* Defined __i386__ */
2661 }
2662 #endif
2663
2664 #ifndef HAVE_GNAT_INIT_FLOAT
2665
2666 /* All targets without a specific __gnat_init_float will use an empty one. */
2667 void
2668 __gnat_init_float (void)
2669 {
2670 }
2671 #endif
2672
2673 /***********************************/
2674 /* __gnat_adjust_context_for_raise */
2675 /***********************************/
2676
2677 #ifndef HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
2678
2679 /* All targets without a specific version will use an empty one. */
2680
2681 /* Given UCONTEXT a pointer to a context structure received by a signal
2682 handler for SIGNO, perform the necessary adjustments to let the handler
2683 raise an exception. Calls to this routine are not conditioned by the
2684 propagation scheme in use. */
2685
2686 void
2687 __gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED,
2688 void *ucontext ATTRIBUTE_UNUSED)
2689 {
2690 /* We used to compensate here for the raised from call vs raised from signal
2691 exception discrepancy with the GCC ZCX scheme, but this now can be dealt
2692 with generically in the unwinder (see GCC PR other/26208). This however
2693 requires the use of the _Unwind_GetIPInfo routine in raise-gcc.c, which
2694 is predicated on the definition of HAVE_GETIPINFO at compile time. Only
2695 the VMS ports still do the compensation described in the few lines below.
2696
2697 *** Call vs signal exception discrepancy with GCC ZCX scheme ***
2698
2699 The GCC unwinder expects to be dealing with call return addresses, since
2700 this is the "nominal" case of what we retrieve while unwinding a regular
2701 call chain.
2702
2703 To evaluate if a handler applies at some point identified by a return
2704 address, the propagation engine needs to determine what region the
2705 corresponding call instruction pertains to. Because the return address
2706 may not be attached to the same region as the call, the unwinder always
2707 subtracts "some" amount from a return address to search the region
2708 tables, amount chosen to ensure that the resulting address is inside the
2709 call instruction.
2710
2711 When we raise an exception from a signal handler, e.g. to transform a
2712 SIGSEGV into Storage_Error, things need to appear as if the signal
2713 handler had been "called" by the instruction which triggered the signal,
2714 so that exception handlers that apply there are considered. What the
2715 unwinder will retrieve as the return address from the signal handler is
2716 what it will find as the faulting instruction address in the signal
2717 context pushed by the kernel. Leaving this address untouched looses, if
2718 the triggering instruction happens to be the very first of a region, as
2719 the later adjustments performed by the unwinder would yield an address
2720 outside that region. We need to compensate for the unwinder adjustments
2721 at some point, and this is what this routine is expected to do.
2722
2723 signo is passed because on some targets for some signals the PC in
2724 context points to the instruction after the faulting one, in which case
2725 the unwinder adjustment is still desired. */
2726 }
2727
2728 #endif
2729
2730 #ifdef __cplusplus
2731 }
2732 #endif