2 * interrupt-handling magic
6 * This software is part of the SBCL system. See the README file for
9 * This software is derived from the CMU CL system, which was
10 * written at Carnegie Mellon University and released into the
11 * public domain. The software is in the public domain and is
12 * provided with absolutely no warranty. See the COPYING and CREDITS
13 * files for more information.
17 /* As far as I can tell, what's going on here is:
19 * In the case of most signals, when Lisp asks us to handle the
20 * signal, the outermost handler (the one actually passed to UNIX) is
21 * either interrupt_handle_now(..) or maybe_now_maybe_later(..).
22 * In that case, the Lisp-level handler is stored in interrupt_handlers[..]
23 * and interrupt_low_level_handlers[..] is cleared.
25 * However, some signals need special handling, e.g.
27 * o the SIGSEGV (for e.g. Linux) or SIGBUS (for e.g. FreeBSD) used by the
28 * garbage collector to detect violations of write protection,
29 * because some cases of such signals (e.g. GC-related violations of
30 * write protection) are handled at C level and never passed on to
31 * Lisp. For such signals, we still store any Lisp-level handler
32 * in interrupt_handlers[..], but for the outermost handle we use
33 * the value from interrupt_low_level_handlers[..], instead of the
34 * ordinary interrupt_handle_now(..) or interrupt_handle_later(..).
36 * o the SIGTRAP (Linux/Alpha) which Lisp code uses to handle breakpoints,
37 * pseudo-atomic sections, and some classes of error (e.g. "function
38 * not defined"). This never goes anywhere near the Lisp handlers at all.
39 * See runtime/alpha-arch.c and code/signal.lisp
41 * - WHN 20000728, dan 20010128 */
49 #include <sys/types.h>
50 #ifndef LISP_FEATURE_WIN32
58 #include "interrupt.h"
66 #include "genesis/fdefn.h"
67 #include "genesis/simple-fun.h"
68 #include "genesis/cons.h"
72 static void run_deferred_handler(struct interrupt_data *data, void *v_context);
73 #ifndef LISP_FEATURE_WIN32
74 static void store_signal_data_for_later (struct interrupt_data *data,
75 void *handler, int signal,
77 os_context_t *context);
78 boolean interrupt_maybe_gc_int(int signal, siginfo_t *info, void *v_context);
81 sigaddset_deferrable(sigset_t *s)
85 sigaddset(s, SIGQUIT);
86 sigaddset(s, SIGPIPE);
87 sigaddset(s, SIGALRM);
89 sigaddset(s, SIGTSTP);
90 sigaddset(s, SIGCHLD);
92 sigaddset(s, SIGXCPU);
93 sigaddset(s, SIGXFSZ);
94 sigaddset(s, SIGVTALRM);
95 sigaddset(s, SIGPROF);
96 sigaddset(s, SIGWINCH);
98 #if !((defined(LISP_FEATURE_DARWIN) || defined(LISP_FEATURE_FREEBSD)) && defined(LISP_FEATURE_SB_THREAD))
99 sigaddset(s, SIGUSR1);
100 sigaddset(s, SIGUSR2);
103 #ifdef LISP_FEATURE_SB_THREAD
104 sigaddset(s, SIG_INTERRUPT_THREAD);
109 sigaddset_blockable(sigset_t *s)
111 sigaddset_deferrable(s);
112 #ifdef LISP_FEATURE_SB_THREAD
113 #ifdef SIG_RESUME_FROM_GC
114 sigaddset(s, SIG_RESUME_FROM_GC);
116 sigaddset(s, SIG_STOP_FOR_GC);
120 /* initialized in interrupt_init */
121 static sigset_t deferrable_sigset;
122 static sigset_t blockable_sigset;
126 check_blockables_blocked_or_lose()
128 #if !defined(LISP_FEATURE_WIN32)
129 /* Get the current sigmask, by blocking the empty set. */
130 sigset_t empty,current;
133 thread_sigmask(SIG_BLOCK, &empty, ¤t);
134 for(i = 1; i < NSIG; i++) {
135 if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i))
136 lose("blockable signal %d not blocked\n",i);
142 check_interrupts_enabled_or_lose(os_context_t *context)
144 struct thread *thread=arch_os_get_current_thread();
145 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
146 lose("interrupts not enabled\n");
148 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
149 (!foreign_function_call_active) &&
151 arch_pseudo_atomic_atomic(context))
152 lose ("in pseudo atomic section\n");
155 /* When we catch an internal error, should we pass it back to Lisp to
156 * be handled in a high-level way? (Early in cold init, the answer is
157 * 'no', because Lisp is still too brain-dead to handle anything.
158 * After sufficient initialization has been completed, the answer
160 boolean internal_errors_enabled = 0;
162 #ifndef LISP_FEATURE_WIN32
163 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*);
165 union interrupt_handler interrupt_handlers[NSIG];
167 /* At the toplevel repl we routinely call this function. The signal
168 * mask ought to be clear anyway most of the time, but may be non-zero
169 * if we were interrupted e.g. while waiting for a queue. */
172 reset_signal_mask(void)
174 #ifndef LISP_FEATURE_WIN32
177 thread_sigmask(SIG_SETMASK,&new,0);
182 block_blockable_signals(void)
184 #ifndef LISP_FEATURE_WIN32
185 thread_sigmask(SIG_BLOCK, &blockable_sigset, 0);
190 block_deferrable_signals(void)
192 #ifndef LISP_FEATURE_WIN32
193 thread_sigmask(SIG_BLOCK, &deferrable_sigset, 0);
199 * utility routines used by various signal handlers
203 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
205 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
209 /* Build a fake stack frame or frames */
211 current_control_frame_pointer =
212 (lispobj *)(unsigned long)
213 (*os_context_register_addr(context, reg_CSP));
214 if ((lispobj *)(unsigned long)
215 (*os_context_register_addr(context, reg_CFP))
216 == current_control_frame_pointer) {
217 /* There is a small window during call where the callee's
218 * frame isn't built yet. */
219 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
220 == FUN_POINTER_LOWTAG) {
221 /* We have called, but not built the new frame, so
222 * build it for them. */
223 current_control_frame_pointer[0] =
224 *os_context_register_addr(context, reg_OCFP);
225 current_control_frame_pointer[1] =
226 *os_context_register_addr(context, reg_LRA);
227 current_control_frame_pointer += 8;
228 /* Build our frame on top of it. */
229 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
232 /* We haven't yet called, build our frame as if the
233 * partial frame wasn't there. */
234 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
237 /* We can't tell whether we are still in the caller if it had to
238 * allocate a stack frame due to stack arguments. */
239 /* This observation provoked some past CMUCL maintainer to ask
240 * "Can anything strange happen during return?" */
243 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
246 current_control_stack_pointer = current_control_frame_pointer + 8;
248 current_control_frame_pointer[0] = oldcont;
249 current_control_frame_pointer[1] = NIL;
250 current_control_frame_pointer[2] =
251 (lispobj)(*os_context_register_addr(context, reg_CODE));
255 /* Stores the context for gc to scavange and builds fake stack
258 fake_foreign_function_call(os_context_t *context)
261 struct thread *thread=arch_os_get_current_thread();
263 /* context_index incrementing must not be interrupted */
264 check_blockables_blocked_or_lose();
266 /* Get current Lisp state from context. */
268 dynamic_space_free_pointer =
269 (lispobj *)(unsigned long)
270 (*os_context_register_addr(context, reg_ALLOC));
271 /* fprintf(stderr,"dynamic_space_free_pointer: %p\n", dynamic_space_free_pointer); */
272 #if defined(LISP_FEATURE_ALPHA)
273 if ((long)dynamic_space_free_pointer & 1) {
274 lose("dead in fake_foreign_function_call, context = %x\n", context);
279 current_binding_stack_pointer =
280 (lispobj *)(unsigned long)
281 (*os_context_register_addr(context, reg_BSP));
284 build_fake_control_stack_frames(thread,context);
286 /* Do dynamic binding of the active interrupt context index
287 * and save the context in the context array. */
289 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
291 if (context_index >= MAX_INTERRUPTS) {
292 lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS);
295 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
296 make_fixnum(context_index + 1),thread);
298 thread->interrupt_contexts[context_index] = context;
300 /* no longer in Lisp now */
301 foreign_function_call_active = 1;
304 /* blocks all blockable signals. If you are calling from a signal handler,
305 * the usual signal mask will be restored from the context when the handler
306 * finishes. Otherwise, be careful */
308 undo_fake_foreign_function_call(os_context_t *context)
310 struct thread *thread=arch_os_get_current_thread();
311 /* Block all blockable signals. */
312 block_blockable_signals();
314 /* going back into Lisp */
315 foreign_function_call_active = 0;
317 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
321 /* Put the dynamic space free pointer back into the context. */
322 *os_context_register_addr(context, reg_ALLOC) =
323 (unsigned long) dynamic_space_free_pointer
324 | (*os_context_register_addr(context, reg_ALLOC)
327 ((unsigned long)(*os_context_register_addr(context, reg_ALLOC)) & ~LOWTAG_MASK)
328 | ((unsigned long) dynamic_space_free_pointer & LOWTAG_MASK);
333 /* a handler for the signal caused by execution of a trap opcode
334 * signalling an internal error */
336 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
341 fake_foreign_function_call(context);
343 if (!internal_errors_enabled) {
344 describe_internal_error(context);
345 /* There's no good way to recover from an internal error
346 * before the Lisp error handling mechanism is set up. */
347 lose("internal error too early in init, can't recover\n");
350 /* Allocate the SAP object while the interrupts are still
352 context_sap = alloc_sap(context);
354 #ifndef LISP_FEATURE_WIN32
355 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
358 SHOW("in interrupt_internal_error");
360 /* Display some rudimentary debugging information about the
361 * error, so that even if the Lisp error handler gets badly
362 * confused, we have a chance to determine what's going on. */
363 describe_internal_error(context);
365 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
366 continuable ? T : NIL);
368 undo_fake_foreign_function_call(context); /* blocks signals again */
370 arch_skip_instruction(context);
374 interrupt_handle_pending(os_context_t *context)
376 struct thread *thread;
377 struct interrupt_data *data;
379 FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n"));
381 check_blockables_blocked_or_lose();
382 thread=arch_os_get_current_thread();
383 data=thread->interrupt_data;
385 /* If pseudo_atomic_interrupted is set then the interrupt is going
386 * to be handled now, ergo it's safe to clear it. */
387 arch_clear_pseudo_atomic_interrupted(context);
389 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
390 #ifdef LISP_FEATURE_SB_THREAD
391 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
392 /* another thread has already initiated a gc, this attempt
393 * might as well be cancelled */
394 SetSymbolValue(GC_PENDING,NIL,thread);
395 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
396 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
399 if (SymbolValue(GC_PENDING,thread) != NIL) {
400 /* GC_PENDING is cleared in SUB-GC, or if another thread
401 * is doing a gc already we will get a SIG_STOP_FOR_GC and
402 * that will clear it. */
403 interrupt_maybe_gc_int(0,NULL,context);
405 check_blockables_blocked_or_lose();
408 /* we may be here only to do the gc stuff, if interrupts are
409 * enabled run the pending handler */
410 if (!((SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) ||
412 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
413 (!foreign_function_call_active) &&
415 arch_pseudo_atomic_atomic(context)))) {
417 /* There may be no pending handler, because it was only a gc
418 * that had to be executed or because pseudo atomic triggered
419 * twice for a single interrupt. For the interested reader,
420 * that may happen if an interrupt hits after the interrupted
421 * flag is cleared but before pseduo-atomic is set and a
422 * pseudo atomic is interrupted in that interrupt. */
423 if (data->pending_handler) {
425 /* If we're here as the result of a pseudo-atomic as opposed
426 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
427 * NIL, because maybe_defer_handler sets
428 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
429 SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
431 #ifndef LISP_FEATURE_WIN32
432 /* restore the saved signal mask from the original signal (the
433 * one that interrupted us during the critical section) into the
434 * os_context for the signal we're currently in the handler for.
435 * This should ensure that when we return from the handler the
436 * blocked signals are unblocked */
437 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
439 sigemptyset(&data->pending_mask);
441 /* This will break on sparc linux: the deferred handler really wants
442 * to be called with a void_context */
443 run_deferred_handler(data,(void *)context);
449 * the two main signal handlers:
450 * interrupt_handle_now(..)
451 * maybe_now_maybe_later(..)
453 * to which we have added interrupt_handle_now_handler(..). Why?
454 * Well, mostly because the SPARC/Linux platform doesn't quite do
455 * signals the way we want them done. The third argument in the
456 * handler isn't filled in by the kernel properly, so we fix it up
457 * ourselves in the arch_os_get_context(..) function; however, we only
458 * want to do this when we first hit the handler, and not when
459 * interrupt_handle_now(..) is being called from some other handler
460 * (when the fixup will already have been done). -- CSR, 2002-07-23
464 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
466 os_context_t *context = (os_context_t*)void_context;
467 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
468 boolean were_in_lisp;
470 union interrupt_handler handler;
472 check_blockables_blocked_or_lose();
475 #ifndef LISP_FEATURE_WIN32
476 if (sigismember(&deferrable_sigset,signal))
477 check_interrupts_enabled_or_lose(context);
480 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
481 /* Under Linux on some architectures, we appear to have to restore
482 the FPU control word from the context, as after the signal is
483 delivered we appear to have a null FPU control word. */
484 os_restore_fp_control(context);
488 handler = interrupt_handlers[signal];
490 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
494 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
495 were_in_lisp = !foreign_function_call_active;
499 fake_foreign_function_call(context);
502 FSHOW_SIGNAL((stderr,
503 "/entering interrupt_handle_now(%d, info, context)\n",
506 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
508 /* This can happen if someone tries to ignore or default one
509 * of the signals we need for runtime support, and the runtime
510 * support decides to pass on it. */
511 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
513 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
514 /* Once we've decided what to do about contexts in a
515 * return-elsewhere world (the original context will no longer
516 * be available; should we copy it or was nobody using it anyway?)
517 * then we should convert this to return-elsewhere */
519 /* CMUCL comment said "Allocate the SAPs while the interrupts
520 * are still disabled.". I (dan, 2003.08.21) assume this is
521 * because we're not in pseudoatomic and allocation shouldn't
522 * be interrupted. In which case it's no longer an issue as
523 * all our allocation from C now goes through a PA wrapper,
524 * but still, doesn't hurt.
526 * Yeah, but non-gencgc platforms don't really wrap allocation
527 * in PA. MG - 2005-08-29 */
529 lispobj info_sap,context_sap = alloc_sap(context);
530 info_sap = alloc_sap(info);
531 /* Leave deferrable signals blocked, the handler itself will
532 * allow signals again when it sees fit. */
533 #ifdef LISP_FEATURE_SB_THREAD
536 sigemptyset(&unblock);
537 sigaddset(&unblock, SIG_STOP_FOR_GC);
538 #ifdef SIG_RESUME_FROM_GC
539 sigaddset(&unblock, SIG_RESUME_FROM_GC);
541 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
545 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
547 funcall3(handler.lisp,
553 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
555 #ifndef LISP_FEATURE_WIN32
556 /* Allow signals again. */
557 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
560 (*handler.c)(signal, info, void_context);
563 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
567 undo_fake_foreign_function_call(context); /* block signals again */
570 FSHOW_SIGNAL((stderr,
571 "/returning from interrupt_handle_now(%d, info, context)\n",
575 /* This is called at the end of a critical section if the indications
576 * are that some signal was deferred during the section. Note that as
577 * far as C or the kernel is concerned we dealt with the signal
578 * already; we're just doing the Lisp-level processing now that we
581 run_deferred_handler(struct interrupt_data *data, void *v_context) {
582 /* The pending_handler may enable interrupts and then another
583 * interrupt may hit, overwrite interrupt_data, so reset the
584 * pending handler before calling it. Trust the handler to finish
585 * with the siginfo before enabling interrupts. */
586 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
588 data->pending_handler=0;
589 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
592 #ifndef LISP_FEATURE_WIN32
594 maybe_defer_handler(void *handler, struct interrupt_data *data,
595 int signal, siginfo_t *info, os_context_t *context)
597 struct thread *thread=arch_os_get_current_thread();
599 check_blockables_blocked_or_lose();
601 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
602 lose("interrupt already pending\n");
603 /* If interrupts are disabled then INTERRUPT_PENDING is set and
604 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
605 * atomic section inside a WITHOUT-INTERRUPTS.
607 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
608 store_signal_data_for_later(data,handler,signal,info,context);
609 SetSymbolValue(INTERRUPT_PENDING, T,thread);
610 FSHOW_SIGNAL((stderr,
611 "/maybe_defer_handler(%x,%d),thread=%lu: deferred\n",
612 (unsigned int)handler,signal,
613 (unsigned long)thread->os_thread));
616 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
617 * actually use its argument for anything on x86, so this branch
618 * may succeed even when context is null (gencgc alloc()) */
620 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
621 /* FIXME: this foreign_function_call_active test is dubious at
622 * best. If a foreign call is made in a pseudo atomic section
623 * (?) or more likely a pseudo atomic section is in a foreign
624 * call then an interrupt is executed immediately. Maybe it
625 * has to do with C code not maintaining pseudo atomic
626 * properly. MG - 2005-08-10 */
627 (!foreign_function_call_active) &&
629 arch_pseudo_atomic_atomic(context)) {
630 store_signal_data_for_later(data,handler,signal,info,context);
631 arch_set_pseudo_atomic_interrupted(context);
632 FSHOW_SIGNAL((stderr,
633 "/maybe_defer_handler(%x,%d),thread=%lu: deferred(PA)\n",
634 (unsigned int)handler,signal,
635 (unsigned long)thread->os_thread));
638 FSHOW_SIGNAL((stderr,
639 "/maybe_defer_handler(%x,%d),thread=%lu: not deferred\n",
640 (unsigned int)handler,signal,
641 (unsigned long)thread->os_thread));
646 store_signal_data_for_later (struct interrupt_data *data, void *handler,
648 siginfo_t *info, os_context_t *context)
650 if (data->pending_handler)
651 lose("tried to overwrite pending interrupt handler %x with %x\n",
652 data->pending_handler, handler);
654 lose("tried to defer null interrupt handler\n");
655 data->pending_handler = handler;
656 data->pending_signal = signal;
658 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
660 FSHOW_SIGNAL((stderr, "/store_signal_data_for_later: signal: %d\n", signal));
663 /* the signal mask in the context (from before we were
664 * interrupted) is copied to be restored when
665 * run_deferred_handler happens. Then the usually-blocked
666 * signals are added to the mask in the context so that we are
667 * running with blocked signals when the handler returns */
668 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
669 sigaddset_deferrable(os_context_sigmask_addr(context));
674 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
676 os_context_t *context = arch_os_get_context(&void_context);
678 struct thread *thread;
679 struct interrupt_data *data;
681 thread=arch_os_get_current_thread();
682 data=thread->interrupt_data;
684 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
685 os_restore_fp_control(context);
688 if(maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
690 interrupt_handle_now(signal, info, context);
691 #ifdef LISP_FEATURE_DARWIN
692 /* Work around G5 bug */
693 DARWIN_FIX_CONTEXT(context);
698 low_level_interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
700 os_context_t *context = (os_context_t*)void_context;
702 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
703 os_restore_fp_control(context);
706 check_blockables_blocked_or_lose();
707 check_interrupts_enabled_or_lose(context);
708 interrupt_low_level_handlers[signal](signal, info, void_context);
709 #ifdef LISP_FEATURE_DARWIN
710 /* Work around G5 bug */
711 DARWIN_FIX_CONTEXT(context);
716 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
718 os_context_t *context = arch_os_get_context(&void_context);
719 struct thread *thread;
720 struct interrupt_data *data;
722 thread=arch_os_get_current_thread();
723 data=thread->interrupt_data;
725 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
726 os_restore_fp_control(context);
729 if(maybe_defer_handler(low_level_interrupt_handle_now,data,
730 signal,info,context))
732 low_level_interrupt_handle_now(signal, info, context);
733 #ifdef LISP_FEATURE_DARWIN
734 /* Work around G5 bug */
735 DARWIN_FIX_CONTEXT(context);
740 #ifdef LISP_FEATURE_SB_THREAD
743 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
745 os_context_t *context = arch_os_get_context(&void_context);
747 struct thread *thread=arch_os_get_current_thread();
750 if ((arch_pseudo_atomic_atomic(context) ||
751 SymbolValue(GC_INHIBIT,thread) != NIL)) {
752 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
753 if (SymbolValue(GC_INHIBIT,thread) == NIL)
754 arch_set_pseudo_atomic_interrupted(context);
755 FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred\n",
758 /* need the context stored so it can have registers scavenged */
759 fake_foreign_function_call(context);
761 sigfillset(&ss); /* Block everything. */
762 thread_sigmask(SIG_BLOCK,&ss,0);
764 if(thread->state!=STATE_RUNNING) {
765 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
766 fixnum_value(thread->state));
768 thread->state=STATE_SUSPENDED;
769 FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread));
771 #if defined(SIG_RESUME_FROM_GC)
772 sigemptyset(&ss); sigaddset(&ss,SIG_RESUME_FROM_GC);
774 sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
777 /* It is possible to get SIGCONT (and probably other
778 * non-blockable signals) here. */
779 #ifdef SIG_RESUME_FROM_GC
782 do { sigwait(&ss, &sigret); }
783 while (sigret != SIG_RESUME_FROM_GC);
786 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
789 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
790 if(thread->state!=STATE_RUNNING) {
791 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
792 fixnum_value(thread->state));
795 undo_fake_foreign_function_call(context);
801 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
803 os_context_t *context = arch_os_get_context(&void_context);
804 interrupt_handle_now(signal, info, context);
805 #ifdef LISP_FEATURE_DARWIN
806 DARWIN_FIX_CONTEXT(context);
811 * stuff to detect and handle hitting the GC trigger
814 #ifndef LISP_FEATURE_GENCGC
815 /* since GENCGC has its own way to record trigger */
817 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
819 if (current_auto_gc_trigger == NULL)
822 void *badaddr=arch_get_bad_addr(signal,info,context);
823 return (badaddr >= (void *)current_auto_gc_trigger &&
824 badaddr <((void *)current_dynamic_space + dynamic_space_size));
829 /* manipulate the signal context and stack such that when the handler
830 * returns, it will call function instead of whatever it was doing
834 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
835 extern int *context_eflags_addr(os_context_t *context);
838 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
839 extern void post_signal_tramp(void);
840 extern void call_into_lisp_tramp(void);
842 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
844 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
845 void * fun=native_pointer(function);
846 void *code = &(((struct simple_fun *) fun)->code);
849 /* Build a stack frame showing `interrupted' so that the
850 * user's backtrace makes (as much) sense (as usual) */
852 /* FIXME: what about restoring fp state? */
853 /* FIXME: what about restoring errno? */
854 #ifdef LISP_FEATURE_X86
855 /* Suppose the existence of some function that saved all
856 * registers, called call_into_lisp, then restored GP registers and
857 * returned. It would look something like this:
865 pushl {address of function to call}
866 call 0x8058db0 <call_into_lisp>
873 * What we do here is set up the stack that call_into_lisp would
874 * expect to see if it had been called by this code, and frob the
875 * signal context so that signal return goes directly to call_into_lisp,
876 * and when that function (and the lisp function it invoked) returns,
877 * it returns to the second half of this imaginary function which
878 * restores all registers and returns to C
880 * For this to work, the latter part of the imaginary function
881 * must obviously exist in reality. That would be post_signal_tramp
884 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
886 #if defined(LISP_FEATURE_DARWIN)
887 u32 *register_save_area = (u32 *)os_validate(0, 0x40);
889 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp));
890 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context));
892 /* 1. os_validate (malloc/mmap) register_save_block
893 * 2. copy register state into register_save_block
894 * 3. put a pointer to register_save_block in a register in the context
895 * 4. set the context's EIP to point to a trampoline which:
896 * a. builds the fake stack frame from the block
898 * c. calls the function
901 *register_save_area = *os_context_pc_addr(context);
902 *(register_save_area + 1) = function;
903 *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI);
904 *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI);
905 *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX);
906 *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX);
907 *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX);
908 *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX);
909 *(register_save_area + 8) = *context_eflags_addr(context);
911 *os_context_pc_addr(context) = call_into_lisp_tramp;
912 *os_context_register_addr(context,reg_ECX) = register_save_area;
915 /* return address for call_into_lisp: */
916 *(sp-15) = (u32)post_signal_tramp;
917 *(sp-14) = function; /* args for call_into_lisp : function*/
918 *(sp-13) = 0; /* arg array */
919 *(sp-12) = 0; /* no. args */
920 /* this order matches that used in POPAD */
921 *(sp-11)=*os_context_register_addr(context,reg_EDI);
922 *(sp-10)=*os_context_register_addr(context,reg_ESI);
924 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
925 /* POPAD ignores the value of ESP: */
927 *(sp-7)=*os_context_register_addr(context,reg_EBX);
929 *(sp-6)=*os_context_register_addr(context,reg_EDX);
930 *(sp-5)=*os_context_register_addr(context,reg_ECX);
931 *(sp-4)=*os_context_register_addr(context,reg_EAX);
932 *(sp-3)=*context_eflags_addr(context);
933 *(sp-2)=*os_context_register_addr(context,reg_EBP);
934 *(sp-1)=*os_context_pc_addr(context);
938 #elif defined(LISP_FEATURE_X86_64)
939 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
940 /* return address for call_into_lisp: */
941 *(sp-18) = (u64)post_signal_tramp;
943 *(sp-17)=*os_context_register_addr(context,reg_R15);
944 *(sp-16)=*os_context_register_addr(context,reg_R14);
945 *(sp-15)=*os_context_register_addr(context,reg_R13);
946 *(sp-14)=*os_context_register_addr(context,reg_R12);
947 *(sp-13)=*os_context_register_addr(context,reg_R11);
948 *(sp-12)=*os_context_register_addr(context,reg_R10);
949 *(sp-11)=*os_context_register_addr(context,reg_R9);
950 *(sp-10)=*os_context_register_addr(context,reg_R8);
951 *(sp-9)=*os_context_register_addr(context,reg_RDI);
952 *(sp-8)=*os_context_register_addr(context,reg_RSI);
953 /* skip RBP and RSP */
954 *(sp-7)=*os_context_register_addr(context,reg_RBX);
955 *(sp-6)=*os_context_register_addr(context,reg_RDX);
956 *(sp-5)=*os_context_register_addr(context,reg_RCX);
957 *(sp-4)=*os_context_register_addr(context,reg_RAX);
958 *(sp-3)=*context_eflags_addr(context);
959 *(sp-2)=*os_context_register_addr(context,reg_RBP);
960 *(sp-1)=*os_context_pc_addr(context);
962 *os_context_register_addr(context,reg_RDI) =
963 (os_context_register_t)function; /* function */
964 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
965 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
967 struct thread *th=arch_os_get_current_thread();
968 build_fake_control_stack_frames(th,context);
971 #ifdef LISP_FEATURE_X86
973 #if !defined(LISP_FEATURE_DARWIN)
974 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
975 *os_context_register_addr(context,reg_ECX) = 0;
976 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
978 *os_context_register_addr(context,reg_UESP) =
979 (os_context_register_t)(sp-15);
981 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
982 #endif /* __NETBSD__ */
983 #endif /* LISP_FEATURE_DARWIN */
985 #elif defined(LISP_FEATURE_X86_64)
986 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
987 *os_context_register_addr(context,reg_RCX) = 0;
988 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
989 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
991 /* this much of the calling convention is common to all
993 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
994 *os_context_register_addr(context,reg_NARGS) = 0;
995 *os_context_register_addr(context,reg_LIP) =
996 (os_context_register_t)(unsigned long)code;
997 *os_context_register_addr(context,reg_CFP) =
998 (os_context_register_t)(unsigned long)current_control_frame_pointer;
1000 #ifdef ARCH_HAS_NPC_REGISTER
1001 *os_context_npc_addr(context) =
1002 4 + *os_context_pc_addr(context);
1004 #ifdef LISP_FEATURE_SPARC
1005 *os_context_register_addr(context,reg_CODE) =
1006 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
1010 #ifdef LISP_FEATURE_SB_THREAD
1012 /* FIXME: this function can go away when all lisp handlers are invoked
1013 * via arrange_return_to_lisp_function. */
1015 interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
1017 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
1019 /* let the handler enable interrupts again when it sees fit */
1020 sigaddset_deferrable(os_context_sigmask_addr(context));
1021 arrange_return_to_lisp_function(context, SymbolFunction(RUN_INTERRUPTION));
1026 /* KLUDGE: Theoretically the approach we use for undefined alien
1027 * variables should work for functions as well, but on PPC/Darwin
1028 * we get bus error at bogus addresses instead, hence this workaround,
1029 * that has the added benefit of automatically discriminating between
1030 * functions and variables.
1033 undefined_alien_function() {
1034 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
1038 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
1040 struct thread *th=arch_os_get_current_thread();
1042 /* note the os_context hackery here. When the signal handler returns,
1043 * it won't go back to what it was doing ... */
1044 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
1045 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1046 /* We hit the end of the control stack: disable guard page
1047 * protection so the error handler has some headroom, protect the
1048 * previous page so that we can catch returns from the guard page
1049 * and restore it. */
1050 protect_control_stack_guard_page(0);
1051 protect_control_stack_return_guard_page(1);
1053 arrange_return_to_lisp_function
1054 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
1057 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
1058 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1059 /* We're returning from the guard page: reprotect it, and
1060 * unprotect this one. This works even if we somehow missed
1061 * the return-guard-page, and hit it on our way to new
1062 * exhaustion instead. */
1063 protect_control_stack_guard_page(1);
1064 protect_control_stack_return_guard_page(0);
1067 else if (addr >= undefined_alien_address &&
1068 addr < undefined_alien_address + os_vm_page_size) {
1069 arrange_return_to_lisp_function
1070 (context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
1076 #ifndef LISP_FEATURE_GENCGC
1077 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
1078 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
1079 * whether the signal was due to treading on the mprotect()ed zone -
1080 * and if so, arrange for a GC to happen. */
1081 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
1084 interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
1086 os_context_t *context=(os_context_t *) void_context;
1088 if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
1089 struct thread *thread=arch_os_get_current_thread();
1090 clear_auto_gc_trigger();
1091 /* Don't flood the system with interrupts if the need to gc is
1092 * already noted. This can happen for example when SUB-GC
1093 * allocates or after a gc triggered in a WITHOUT-GCING. */
1094 if (SymbolValue(GC_PENDING,thread) == NIL) {
1095 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
1096 if (arch_pseudo_atomic_atomic(context)) {
1097 /* set things up so that GC happens when we finish
1099 SetSymbolValue(GC_PENDING,T,thread);
1100 arch_set_pseudo_atomic_interrupted(context);
1102 interrupt_maybe_gc_int(signal,info,void_context);
1105 SetSymbolValue(GC_PENDING,T,thread);
1115 /* this is also used by gencgc, in alloc() */
1117 interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
1119 os_context_t *context=(os_context_t *) void_context;
1120 #ifndef LISP_FEATURE_WIN32
1121 struct thread *thread=arch_os_get_current_thread();
1124 fake_foreign_function_call(context);
1126 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
1127 * which case we will be running with no gc trigger barrier
1128 * thing for a while. But it shouldn't be long until the end
1131 * FIXME: It would be good to protect the end of dynamic space
1132 * and signal a storage condition from there.
1135 /* Restore the signal mask from the interrupted context before
1136 * calling into Lisp if interrupts are enabled. Why not always?
1138 * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an
1139 * interrupt hits while in SUB-GC, it is deferred and the
1140 * os_context_sigmask of that interrupt is set to block further
1141 * deferrable interrupts (until the first one is
1142 * handled). Unfortunately, that context refers to this place and
1143 * when we return from here the signals will not be blocked.
1145 * A kludgy alternative is to propagate the sigmask change to the
1148 #ifndef LISP_FEATURE_WIN32
1149 if(SymbolValue(INTERRUPTS_ENABLED,thread)!=NIL)
1150 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1151 #ifdef LISP_FEATURE_SB_THREAD
1155 #if defined(SIG_RESUME_FROM_GC)
1156 sigaddset(&new,SIG_RESUME_FROM_GC);
1158 sigaddset(&new,SIG_STOP_FOR_GC);
1159 thread_sigmask(SIG_UNBLOCK,&new,0);
1163 funcall0(SymbolFunction(SUB_GC));
1165 undo_fake_foreign_function_call(context);
1171 * noise to install handlers
1174 #ifndef LISP_FEATURE_WIN32
1175 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1176 * they are blocked, in Linux 2.6 the default handler is invoked
1177 * instead that usually coredumps. One might hastily think that adding
1178 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1179 * the whole sa_mask is ignored and instead of not adding the signal
1180 * in question to the mask. That means if it's not blockable the
1181 * signal must be unblocked at the beginning of signal handlers.
1183 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1184 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1185 * will be unblocked in the sigmask during the signal handler. -- RMK
1188 static volatile int sigaction_nodefer_works = -1;
1190 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1191 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1194 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1196 sigset_t empty, current;
1198 sigemptyset(&empty);
1199 thread_sigmask(SIG_BLOCK, &empty, ¤t);
1200 /* There should be exactly two blocked signals: the two we added
1201 * to sa_mask when setting up the handler. NetBSD doesn't block
1202 * the signal we're handling when SA_NODEFER is set; Linux before
1203 * 2.6.13 or so also doesn't block the other signal when
1204 * SA_NODEFER is set. */
1205 for(i = 1; i < NSIG; i++)
1206 if (sigismember(¤t, i) !=
1207 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1208 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1209 sigaction_nodefer_works = 0;
1211 if (sigaction_nodefer_works == -1)
1212 sigaction_nodefer_works = 1;
1216 see_if_sigaction_nodefer_works()
1218 struct sigaction sa, old_sa;
1220 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1221 sa.sa_sigaction = sigaction_nodefer_test_handler;
1222 sigemptyset(&sa.sa_mask);
1223 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1224 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1225 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1226 /* Make sure no signals are blocked. */
1229 sigemptyset(&empty);
1230 thread_sigmask(SIG_SETMASK, &empty, 0);
1232 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1233 while (sigaction_nodefer_works == -1);
1234 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1237 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1238 #undef SA_NODEFER_TEST_KILL_SIGNAL
1241 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1245 sigemptyset(&unblock);
1246 sigaddset(&unblock, signal);
1247 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1248 interrupt_handle_now_handler(signal, info, void_context);
1252 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1256 sigemptyset(&unblock);
1257 sigaddset(&unblock, signal);
1258 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1259 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1263 undoably_install_low_level_interrupt_handler (int signal,
1268 struct sigaction sa;
1270 if (0 > signal || signal >= NSIG) {
1271 lose("bad signal number %d\n", signal);
1274 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1275 sa.sa_sigaction = handler;
1276 else if (sigismember(&deferrable_sigset,signal))
1277 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1278 /* The use of a trampoline appears to break the
1279 arch_os_get_context() workaround for SPARC/Linux. For now,
1280 don't use the trampoline (and so be vulnerable to the problems
1281 that SA_NODEFER is meant to solve. */
1282 #if !(defined(LISP_FEATURE_SPARC) && defined(LISP_FEATURE_LINUX))
1283 else if (!sigaction_nodefer_works &&
1284 !sigismember(&blockable_sigset, signal))
1285 sa.sa_sigaction = low_level_unblock_me_trampoline;
1288 sa.sa_sigaction = handler;
1290 sigcopyset(&sa.sa_mask, &blockable_sigset);
1291 sa.sa_flags = SA_SIGINFO | SA_RESTART
1292 | (sigaction_nodefer_works ? SA_NODEFER : 0);
1293 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1294 if((signal==SIG_MEMORY_FAULT)
1295 #ifdef SIG_MEMORY_FAULT2
1296 || (signal==SIG_MEMORY_FAULT2)
1298 #ifdef SIG_INTERRUPT_THREAD
1299 || (signal==SIG_INTERRUPT_THREAD)
1302 sa.sa_flags |= SA_ONSTACK;
1305 sigaction(signal, &sa, NULL);
1306 interrupt_low_level_handlers[signal] =
1307 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1311 /* This is called from Lisp. */
1313 install_handler(int signal, void handler(int, siginfo_t*, void*))
1315 #ifndef LISP_FEATURE_WIN32
1316 struct sigaction sa;
1318 union interrupt_handler oldhandler;
1320 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1323 sigaddset(&new, signal);
1324 thread_sigmask(SIG_BLOCK, &new, &old);
1326 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1327 (unsigned int)interrupt_low_level_handlers[signal]));
1328 if (interrupt_low_level_handlers[signal]==0) {
1329 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1330 ARE_SAME_HANDLER(handler, SIG_IGN))
1331 sa.sa_sigaction = handler;
1332 else if (sigismember(&deferrable_sigset, signal))
1333 sa.sa_sigaction = maybe_now_maybe_later;
1334 else if (!sigaction_nodefer_works &&
1335 !sigismember(&blockable_sigset, signal))
1336 sa.sa_sigaction = unblock_me_trampoline;
1338 sa.sa_sigaction = interrupt_handle_now_handler;
1340 sigcopyset(&sa.sa_mask, &blockable_sigset);
1341 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1342 (sigaction_nodefer_works ? SA_NODEFER : 0);
1343 sigaction(signal, &sa, NULL);
1346 oldhandler = interrupt_handlers[signal];
1347 interrupt_handlers[signal].c = handler;
1349 thread_sigmask(SIG_SETMASK, &old, 0);
1351 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1353 return (unsigned long)oldhandler.lisp;
1355 /* Probably-wrong Win32 hack */
1363 #ifndef LISP_FEATURE_WIN32
1365 SHOW("entering interrupt_init()");
1366 see_if_sigaction_nodefer_works();
1367 sigemptyset(&deferrable_sigset);
1368 sigemptyset(&blockable_sigset);
1369 sigaddset_deferrable(&deferrable_sigset);
1370 sigaddset_blockable(&blockable_sigset);
1372 /* Set up high level handler information. */
1373 for (i = 0; i < NSIG; i++) {
1374 interrupt_handlers[i].c =
1375 /* (The cast here blasts away the distinction between
1376 * SA_SIGACTION-style three-argument handlers and
1377 * signal(..)-style one-argument handlers, which is OK
1378 * because it works to call the 1-argument form where the
1379 * 3-argument form is expected.) */
1380 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1383 SHOW("returning from interrupt_init()");
1387 #ifndef LISP_FEATURE_WIN32
1389 siginfo_code(siginfo_t *info)
1391 return info->si_code;
1393 os_vm_address_t current_memory_fault_address;
1396 lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr)
1398 /* FIXME: This is lossy: if we get another memory fault (eg. from
1399 * another thread) before lisp has read this, we the information.
1400 * However, since this is mostly informative, we'll live with that for
1401 * now -- some address is better then no address in this case.
1403 current_memory_fault_address = addr;
1404 arrange_return_to_lisp_function(context, SymbolFunction(MEMORY_FAULT_ERROR));