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 "pseudo-atomic.h"
67 #include "genesis/fdefn.h"
68 #include "genesis/simple-fun.h"
69 #include "genesis/cons.h"
71 static void run_deferred_handler(struct interrupt_data *data, void *v_context);
72 #ifndef LISP_FEATURE_WIN32
73 static void store_signal_data_for_later (struct interrupt_data *data,
74 void *handler, int signal,
76 os_context_t *context);
79 fill_current_sigmask(sigset_t *sigset)
81 /* Get the current sigmask, by blocking the empty set. */
84 thread_sigmask(SIG_BLOCK, &empty, sigset);
88 sigaddset_deferrable(sigset_t *s)
92 sigaddset(s, SIGTERM);
93 sigaddset(s, SIGQUIT);
94 sigaddset(s, SIGPIPE);
95 sigaddset(s, SIGALRM);
97 sigaddset(s, SIGTSTP);
98 sigaddset(s, SIGCHLD);
100 #ifndef LISP_FEATURE_HPUX
101 sigaddset(s, SIGXCPU);
102 sigaddset(s, SIGXFSZ);
104 sigaddset(s, SIGVTALRM);
105 sigaddset(s, SIGPROF);
106 sigaddset(s, SIGWINCH);
108 #if !((defined(LISP_FEATURE_DARWIN) || defined(LISP_FEATURE_FREEBSD)) && defined(LISP_FEATURE_SB_THREAD))
109 sigaddset(s, SIGUSR1);
110 sigaddset(s, SIGUSR2);
113 #ifdef LISP_FEATURE_SB_THREAD
114 sigaddset(s, SIG_INTERRUPT_THREAD);
119 sigaddset_blockable(sigset_t *s)
121 sigaddset_deferrable(s);
122 #ifdef LISP_FEATURE_SB_THREAD
123 #ifdef SIG_RESUME_FROM_GC
124 sigaddset(s, SIG_RESUME_FROM_GC);
126 sigaddset(s, SIG_STOP_FOR_GC);
130 /* initialized in interrupt_init */
131 sigset_t deferrable_sigset;
132 sigset_t blockable_sigset;
136 check_deferrables_blocked_in_sigset_or_lose(sigset_t *sigset)
138 #if !defined(LISP_FEATURE_WIN32)
140 for(i = 1; i < NSIG; i++) {
141 if (sigismember(&deferrable_sigset, i) && !sigismember(sigset, i))
142 lose("deferrable signal %d not blocked\n",i);
148 check_deferrables_blocked_or_lose(void)
150 #if !defined(LISP_FEATURE_WIN32)
152 fill_current_sigmask(¤t);
153 check_deferrables_blocked_in_sigset_or_lose(¤t);
158 check_blockables_blocked_or_lose(void)
160 #if !defined(LISP_FEATURE_WIN32)
161 /* Get the current sigmask, by blocking the empty set. */
162 sigset_t empty,current;
165 thread_sigmask(SIG_BLOCK, &empty, ¤t);
166 for(i = 1; i < NSIG; i++) {
167 if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i))
168 lose("blockable signal %d not blocked\n",i);
174 unblock_gc_signals(void)
176 #ifdef LISP_FEATURE_SB_THREAD
179 #if defined(SIG_RESUME_FROM_GC)
180 sigaddset(&new,SIG_RESUME_FROM_GC);
182 sigaddset(&new,SIG_STOP_FOR_GC);
183 thread_sigmask(SIG_UNBLOCK,&new,0);
188 check_interrupts_enabled_or_lose(os_context_t *context)
190 struct thread *thread=arch_os_get_current_thread();
191 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
192 lose("interrupts not enabled\n");
193 if (arch_pseudo_atomic_atomic(context))
194 lose ("in pseudo atomic section\n");
197 /* When we catch an internal error, should we pass it back to Lisp to
198 * be handled in a high-level way? (Early in cold init, the answer is
199 * 'no', because Lisp is still too brain-dead to handle anything.
200 * After sufficient initialization has been completed, the answer
202 boolean internal_errors_enabled = 0;
204 #ifndef LISP_FEATURE_WIN32
205 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*);
207 union interrupt_handler interrupt_handlers[NSIG];
209 /* At the toplevel repl we routinely call this function. The signal
210 * mask ought to be clear anyway most of the time, but may be non-zero
211 * if we were interrupted e.g. while waiting for a queue. */
214 reset_signal_mask(void)
216 #ifndef LISP_FEATURE_WIN32
219 thread_sigmask(SIG_SETMASK,&new,0);
224 block_blockable_signals(void)
226 #ifndef LISP_FEATURE_WIN32
227 thread_sigmask(SIG_BLOCK, &blockable_sigset, 0);
232 block_deferrable_signals(void)
234 #ifndef LISP_FEATURE_WIN32
235 thread_sigmask(SIG_BLOCK, &deferrable_sigset, 0);
241 * utility routines used by various signal handlers
245 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
247 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
251 /* Build a fake stack frame or frames */
253 current_control_frame_pointer =
254 (lispobj *)(unsigned long)
255 (*os_context_register_addr(context, reg_CSP));
256 if ((lispobj *)(unsigned long)
257 (*os_context_register_addr(context, reg_CFP))
258 == current_control_frame_pointer) {
259 /* There is a small window during call where the callee's
260 * frame isn't built yet. */
261 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
262 == FUN_POINTER_LOWTAG) {
263 /* We have called, but not built the new frame, so
264 * build it for them. */
265 current_control_frame_pointer[0] =
266 *os_context_register_addr(context, reg_OCFP);
267 current_control_frame_pointer[1] =
268 *os_context_register_addr(context, reg_LRA);
269 current_control_frame_pointer += 8;
270 /* Build our frame on top of it. */
271 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
274 /* We haven't yet called, build our frame as if the
275 * partial frame wasn't there. */
276 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
279 /* We can't tell whether we are still in the caller if it had to
280 * allocate a stack frame due to stack arguments. */
281 /* This observation provoked some past CMUCL maintainer to ask
282 * "Can anything strange happen during return?" */
285 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
288 current_control_stack_pointer = current_control_frame_pointer + 8;
290 current_control_frame_pointer[0] = oldcont;
291 current_control_frame_pointer[1] = NIL;
292 current_control_frame_pointer[2] =
293 (lispobj)(*os_context_register_addr(context, reg_CODE));
297 /* Stores the context for gc to scavange and builds fake stack
300 fake_foreign_function_call(os_context_t *context)
303 struct thread *thread=arch_os_get_current_thread();
305 /* context_index incrementing must not be interrupted */
306 check_blockables_blocked_or_lose();
308 /* Get current Lisp state from context. */
310 dynamic_space_free_pointer =
311 (lispobj *)(unsigned long)
312 (*os_context_register_addr(context, reg_ALLOC));
313 /* fprintf(stderr,"dynamic_space_free_pointer: %p\n", */
314 /* dynamic_space_free_pointer); */
315 #if defined(LISP_FEATURE_ALPHA) || defined(LISP_FEATURE_MIPS)
316 if ((long)dynamic_space_free_pointer & 1) {
317 lose("dead in fake_foreign_function_call, context = %x\n", context);
320 /* why doesnt PPC and SPARC do something like this: */
321 #if defined(LISP_FEATURE_HPPA)
322 if ((long)dynamic_space_free_pointer & 4) {
323 lose("dead in fake_foreign_function_call, context = %x, d_s_f_p = %x\n", context, dynamic_space_free_pointer);
328 current_binding_stack_pointer =
329 (lispobj *)(unsigned long)
330 (*os_context_register_addr(context, reg_BSP));
333 build_fake_control_stack_frames(thread,context);
335 /* Do dynamic binding of the active interrupt context index
336 * and save the context in the context array. */
338 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
340 if (context_index >= MAX_INTERRUPTS) {
341 lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS);
344 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
345 make_fixnum(context_index + 1),thread);
347 thread->interrupt_contexts[context_index] = context;
349 #ifdef FOREIGN_FUNCTION_CALL_FLAG
350 foreign_function_call_active = 1;
354 /* blocks all blockable signals. If you are calling from a signal handler,
355 * the usual signal mask will be restored from the context when the handler
356 * finishes. Otherwise, be careful */
358 undo_fake_foreign_function_call(os_context_t *context)
360 struct thread *thread=arch_os_get_current_thread();
361 /* Block all blockable signals. */
362 block_blockable_signals();
364 #ifdef FOREIGN_FUNCTION_CALL_FLAG
365 foreign_function_call_active = 0;
368 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
372 /* Put the dynamic space free pointer back into the context. */
373 *os_context_register_addr(context, reg_ALLOC) =
374 (unsigned long) dynamic_space_free_pointer
375 | (*os_context_register_addr(context, reg_ALLOC)
378 ((unsigned long)(*os_context_register_addr(context, reg_ALLOC))
380 | ((unsigned long) dynamic_space_free_pointer & LOWTAG_MASK);
385 /* a handler for the signal caused by execution of a trap opcode
386 * signalling an internal error */
388 interrupt_internal_error(os_context_t *context, boolean continuable)
392 fake_foreign_function_call(context);
394 if (!internal_errors_enabled) {
395 describe_internal_error(context);
396 /* There's no good way to recover from an internal error
397 * before the Lisp error handling mechanism is set up. */
398 lose("internal error too early in init, can't recover\n");
401 /* Allocate the SAP object while the interrupts are still
403 context_sap = alloc_sap(context);
405 #ifndef LISP_FEATURE_WIN32
406 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
409 SHOW("in interrupt_internal_error");
411 /* Display some rudimentary debugging information about the
412 * error, so that even if the Lisp error handler gets badly
413 * confused, we have a chance to determine what's going on. */
414 describe_internal_error(context);
416 funcall2(StaticSymbolFunction(INTERNAL_ERROR), context_sap,
417 continuable ? T : NIL);
419 undo_fake_foreign_function_call(context); /* blocks signals again */
421 arch_skip_instruction(context);
425 interrupt_handle_pending(os_context_t *context)
427 /* There are three ways we can get here. First, if an interrupt
428 * occurs within pseudo-atomic, it will be deferred, and we'll
429 * trap to here at the end of the pseudo-atomic block. Second, if
430 * the GC (in alloc()) decides that a GC is required, it will set
431 * *GC-PENDING* and pseudo-atomic-interrupted if not *GC-INHIBIT*,
432 * and alloc() is always called from within pseudo-atomic, and
433 * thus we end up here again. Third, when calling GC-ON or at the
434 * end of a WITHOUT-GCING, MAYBE-HANDLE-PENDING-GC will trap to
435 * here if there is a pending GC. Fourth, ahem, at the end of
436 * WITHOUT-INTERRUPTS (bar complications with nesting). */
438 /* Win32 only needs to handle the GC cases (for now?) */
440 struct thread *thread;
442 if (arch_pseudo_atomic_atomic(context)) {
443 lose("Handling pending interrupt in pseduo atomic.");
446 thread = arch_os_get_current_thread();
448 FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n"));
450 check_blockables_blocked_or_lose();
452 /* If pseudo_atomic_interrupted is set then the interrupt is going
453 * to be handled now, ergo it's safe to clear it. */
454 arch_clear_pseudo_atomic_interrupted(context);
456 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
457 #ifdef LISP_FEATURE_SB_THREAD
458 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
459 /* STOP_FOR_GC_PENDING and GC_PENDING are cleared by
460 * the signal handler if it actually stops us. */
461 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
464 if (SymbolValue(GC_PENDING,thread) != NIL) {
465 /* GC_PENDING is cleared in SUB-GC, or if another thread
466 * is doing a gc already we will get a SIG_STOP_FOR_GC and
467 * that will clear it. */
470 check_blockables_blocked_or_lose();
473 #ifndef LISP_FEATURE_WIN32
474 /* we may be here only to do the gc stuff, if interrupts are
475 * enabled run the pending handler */
476 if (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) {
477 struct interrupt_data *data = thread->interrupt_data;
479 /* There may be no pending handler, because it was only a gc
480 * that had to be executed or because pseudo atomic triggered
481 * twice for a single interrupt. For the interested reader,
482 * that may happen if an interrupt hits after the interrupted
483 * flag is cleared but before pseudo-atomic is set and a
484 * pseudo atomic is interrupted in that interrupt. */
485 if (data->pending_handler) {
487 /* If we're here as the result of a pseudo-atomic as opposed
488 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
489 * NIL, because maybe_defer_handler sets
490 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
491 SetSymbolValue(INTERRUPT_PENDING, NIL, thread);
493 /* restore the saved signal mask from the original signal (the
494 * one that interrupted us during the critical section) into the
495 * os_context for the signal we're currently in the handler for.
496 * This should ensure that when we return from the handler the
497 * blocked signals are unblocked */
498 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
500 sigemptyset(&data->pending_mask);
501 /* This will break on sparc linux: the deferred handler really wants
502 * to be called with a void_context */
503 run_deferred_handler(data,(void *)context);
510 * the two main signal handlers:
511 * interrupt_handle_now(..)
512 * maybe_now_maybe_later(..)
514 * to which we have added interrupt_handle_now_handler(..). Why?
515 * Well, mostly because the SPARC/Linux platform doesn't quite do
516 * signals the way we want them done. The third argument in the
517 * handler isn't filled in by the kernel properly, so we fix it up
518 * ourselves in the arch_os_get_context(..) function; however, we only
519 * want to do this when we first hit the handler, and not when
520 * interrupt_handle_now(..) is being called from some other handler
521 * (when the fixup will already have been done). -- CSR, 2002-07-23
525 interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
527 #ifdef FOREIGN_FUNCTION_CALL_FLAG
528 boolean were_in_lisp;
530 union interrupt_handler handler;
532 check_blockables_blocked_or_lose();
534 #ifndef LISP_FEATURE_WIN32
535 if (sigismember(&deferrable_sigset,signal))
536 check_interrupts_enabled_or_lose(context);
539 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
540 /* Under Linux on some architectures, we appear to have to restore
541 the FPU control word from the context, as after the signal is
542 delivered we appear to have a null FPU control word. */
543 os_restore_fp_control(context);
546 handler = interrupt_handlers[signal];
548 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
552 #ifdef FOREIGN_FUNCTION_CALL_FLAG
553 were_in_lisp = !foreign_function_call_active;
557 fake_foreign_function_call(context);
560 FSHOW_SIGNAL((stderr,
561 "/entering interrupt_handle_now(%d, info, context)\n",
564 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
566 /* This can happen if someone tries to ignore or default one
567 * of the signals we need for runtime support, and the runtime
568 * support decides to pass on it. */
569 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
571 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
572 /* Once we've decided what to do about contexts in a
573 * return-elsewhere world (the original context will no longer
574 * be available; should we copy it or was nobody using it anyway?)
575 * then we should convert this to return-elsewhere */
577 /* CMUCL comment said "Allocate the SAPs while the interrupts
578 * are still disabled.". I (dan, 2003.08.21) assume this is
579 * because we're not in pseudoatomic and allocation shouldn't
580 * be interrupted. In which case it's no longer an issue as
581 * all our allocation from C now goes through a PA wrapper,
582 * but still, doesn't hurt.
584 * Yeah, but non-gencgc platforms don't really wrap allocation
585 * in PA. MG - 2005-08-29 */
587 lispobj info_sap,context_sap = alloc_sap(context);
588 info_sap = alloc_sap(info);
589 /* Leave deferrable signals blocked, the handler itself will
590 * allow signals again when it sees fit. */
591 #ifdef LISP_FEATURE_SB_THREAD
594 sigemptyset(&unblock);
595 sigaddset(&unblock, SIG_STOP_FOR_GC);
596 #ifdef SIG_RESUME_FROM_GC
597 sigaddset(&unblock, SIG_RESUME_FROM_GC);
599 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
603 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
605 funcall3(handler.lisp,
611 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
613 #ifndef LISP_FEATURE_WIN32
614 /* Allow signals again. */
615 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
617 (*handler.c)(signal, info, context);
620 #ifdef FOREIGN_FUNCTION_CALL_FLAG
624 undo_fake_foreign_function_call(context); /* block signals again */
627 FSHOW_SIGNAL((stderr,
628 "/returning from interrupt_handle_now(%d, info, context)\n",
632 /* This is called at the end of a critical section if the indications
633 * are that some signal was deferred during the section. Note that as
634 * far as C or the kernel is concerned we dealt with the signal
635 * already; we're just doing the Lisp-level processing now that we
638 run_deferred_handler(struct interrupt_data *data, void *v_context)
640 /* The pending_handler may enable interrupts and then another
641 * interrupt may hit, overwrite interrupt_data, so reset the
642 * pending handler before calling it. Trust the handler to finish
643 * with the siginfo before enabling interrupts. */
644 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
646 data->pending_handler=0;
647 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
650 #ifndef LISP_FEATURE_WIN32
652 maybe_defer_handler(void *handler, struct interrupt_data *data,
653 int signal, siginfo_t *info, os_context_t *context)
655 struct thread *thread=arch_os_get_current_thread();
657 check_blockables_blocked_or_lose();
659 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
660 lose("interrupt already pending\n");
661 /* If interrupts are disabled then INTERRUPT_PENDING is set and
662 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
663 * atomic section inside a WITHOUT-INTERRUPTS.
665 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
666 store_signal_data_for_later(data,handler,signal,info,context);
667 SetSymbolValue(INTERRUPT_PENDING, T,thread);
668 FSHOW_SIGNAL((stderr,
669 "/maybe_defer_handler(%x,%d): deferred\n",
670 (unsigned int)handler,signal));
673 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
674 * actually use its argument for anything on x86, so this branch
675 * may succeed even when context is null (gencgc alloc()) */
676 if (arch_pseudo_atomic_atomic(context)) {
677 store_signal_data_for_later(data,handler,signal,info,context);
678 arch_set_pseudo_atomic_interrupted(context);
679 FSHOW_SIGNAL((stderr,
680 "/maybe_defer_handler(%x,%d): deferred(PA)\n",
681 (unsigned int)handler,signal));
684 FSHOW_SIGNAL((stderr,
685 "/maybe_defer_handler(%x,%d): not deferred\n",
686 (unsigned int)handler,signal));
691 store_signal_data_for_later (struct interrupt_data *data, void *handler,
693 siginfo_t *info, os_context_t *context)
695 if (data->pending_handler)
696 lose("tried to overwrite pending interrupt handler %x with %x\n",
697 data->pending_handler, handler);
699 lose("tried to defer null interrupt handler\n");
700 data->pending_handler = handler;
701 data->pending_signal = signal;
703 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
705 FSHOW_SIGNAL((stderr, "/store_signal_data_for_later: signal: %d\n",
709 /* the signal mask in the context (from before we were
710 * interrupted) is copied to be restored when
711 * run_deferred_handler happens. Then the usually-blocked
712 * signals are added to the mask in the context so that we are
713 * running with blocked signals when the handler returns */
714 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
715 sigaddset_deferrable(os_context_sigmask_addr(context));
720 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
722 os_context_t *context = arch_os_get_context(&void_context);
723 struct thread *thread = arch_os_get_current_thread();
724 struct interrupt_data *data = thread->interrupt_data;
726 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
727 os_restore_fp_control(context);
730 if(!maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
731 interrupt_handle_now(signal, info, context);
735 low_level_interrupt_handle_now(int signal, siginfo_t *info,
736 os_context_t *context)
738 /* No FP control fixage needed, caller has done that. */
739 check_blockables_blocked_or_lose();
740 check_interrupts_enabled_or_lose(context);
741 (*interrupt_low_level_handlers[signal])(signal, info, context);
742 /* No Darwin context fixage needed, caller does that. */
746 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
748 os_context_t *context = arch_os_get_context(&void_context);
749 struct thread *thread = arch_os_get_current_thread();
750 struct interrupt_data *data = thread->interrupt_data;
752 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
753 os_restore_fp_control(context);
756 if(!maybe_defer_handler(low_level_interrupt_handle_now,data,
757 signal,info,context))
758 low_level_interrupt_handle_now(signal, info, context);
762 #ifdef LISP_FEATURE_SB_THREAD
765 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
767 os_context_t *context = arch_os_get_context(&void_context);
769 struct thread *thread=arch_os_get_current_thread();
772 if (arch_pseudo_atomic_atomic(context)) {
773 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
774 arch_set_pseudo_atomic_interrupted(context);
775 FSHOW_SIGNAL((stderr, "sig_stop_for_gc deferred (PA)\n"));
778 else if (SymbolValue(GC_INHIBIT,thread) != NIL) {
779 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
780 FSHOW_SIGNAL((stderr, "sig_stop_for_gc deferred (*GC-INHIBIT*)\n"));
784 /* Not PA and GC not inhibited -- we can stop now. */
786 /* need the context stored so it can have registers scavenged */
787 fake_foreign_function_call(context);
789 /* Block everything. */
791 thread_sigmask(SIG_BLOCK,&ss,0);
793 /* Not pending anymore. */
794 SetSymbolValue(GC_PENDING,NIL,thread);
795 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
797 if(thread->state!=STATE_RUNNING) {
798 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
799 fixnum_value(thread->state));
802 thread->state=STATE_SUSPENDED;
803 FSHOW_SIGNAL((stderr,"suspended\n"));
806 #if defined(SIG_RESUME_FROM_GC)
807 sigaddset(&ss,SIG_RESUME_FROM_GC);
809 sigaddset(&ss,SIG_STOP_FOR_GC);
812 /* It is possible to get SIGCONT (and probably other non-blockable
814 #ifdef SIG_RESUME_FROM_GC
817 do { sigwait(&ss, &sigret); }
818 while (sigret != SIG_RESUME_FROM_GC);
821 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
824 FSHOW_SIGNAL((stderr,"resumed\n"));
825 if(thread->state!=STATE_RUNNING) {
826 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
827 fixnum_value(thread->state));
830 undo_fake_foreign_function_call(context);
835 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
837 os_context_t *context = arch_os_get_context(&void_context);
838 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
839 os_restore_fp_control(context);
840 #ifndef LISP_FEATURE_WIN32
841 if ((signal == SIGILL) || (signal == SIGBUS)
842 #ifndef LISP_FEATURE_LINUX
843 || (signal == SIGEMT)
846 corruption_warning_and_maybe_lose("Signal %d recieved", signal);
849 interrupt_handle_now(signal, info, context);
852 /* manipulate the signal context and stack such that when the handler
853 * returns, it will call function instead of whatever it was doing
857 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
858 extern int *context_eflags_addr(os_context_t *context);
861 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
862 extern void post_signal_tramp(void);
863 extern void call_into_lisp_tramp(void);
865 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
867 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
868 void * fun=native_pointer(function);
869 void *code = &(((struct simple_fun *) fun)->code);
872 /* Build a stack frame showing `interrupted' so that the
873 * user's backtrace makes (as much) sense (as usual) */
875 /* FIXME: what about restoring fp state? */
876 /* FIXME: what about restoring errno? */
877 #ifdef LISP_FEATURE_X86
878 /* Suppose the existence of some function that saved all
879 * registers, called call_into_lisp, then restored GP registers and
880 * returned. It would look something like this:
888 pushl {address of function to call}
889 call 0x8058db0 <call_into_lisp>
896 * What we do here is set up the stack that call_into_lisp would
897 * expect to see if it had been called by this code, and frob the
898 * signal context so that signal return goes directly to call_into_lisp,
899 * and when that function (and the lisp function it invoked) returns,
900 * it returns to the second half of this imaginary function which
901 * restores all registers and returns to C
903 * For this to work, the latter part of the imaginary function
904 * must obviously exist in reality. That would be post_signal_tramp
907 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
909 #if defined(LISP_FEATURE_DARWIN)
910 u32 *register_save_area = (u32 *)os_validate(0, 0x40);
912 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp));
913 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context));
915 /* 1. os_validate (malloc/mmap) register_save_block
916 * 2. copy register state into register_save_block
917 * 3. put a pointer to register_save_block in a register in the context
918 * 4. set the context's EIP to point to a trampoline which:
919 * a. builds the fake stack frame from the block
921 * c. calls the function
924 *register_save_area = *os_context_pc_addr(context);
925 *(register_save_area + 1) = function;
926 *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI);
927 *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI);
928 *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX);
929 *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX);
930 *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX);
931 *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX);
932 *(register_save_area + 8) = *context_eflags_addr(context);
934 *os_context_pc_addr(context) =
935 (os_context_register_t) call_into_lisp_tramp;
936 *os_context_register_addr(context,reg_ECX) =
937 (os_context_register_t) register_save_area;
940 /* return address for call_into_lisp: */
941 *(sp-15) = (u32)post_signal_tramp;
942 *(sp-14) = function; /* args for call_into_lisp : function*/
943 *(sp-13) = 0; /* arg array */
944 *(sp-12) = 0; /* no. args */
945 /* this order matches that used in POPAD */
946 *(sp-11)=*os_context_register_addr(context,reg_EDI);
947 *(sp-10)=*os_context_register_addr(context,reg_ESI);
949 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
950 /* POPAD ignores the value of ESP: */
952 *(sp-7)=*os_context_register_addr(context,reg_EBX);
954 *(sp-6)=*os_context_register_addr(context,reg_EDX);
955 *(sp-5)=*os_context_register_addr(context,reg_ECX);
956 *(sp-4)=*os_context_register_addr(context,reg_EAX);
957 *(sp-3)=*context_eflags_addr(context);
958 *(sp-2)=*os_context_register_addr(context,reg_EBP);
959 *(sp-1)=*os_context_pc_addr(context);
963 #elif defined(LISP_FEATURE_X86_64)
964 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
966 /* return address for call_into_lisp: */
967 *(sp-18) = (u64)post_signal_tramp;
969 *(sp-17)=*os_context_register_addr(context,reg_R15);
970 *(sp-16)=*os_context_register_addr(context,reg_R14);
971 *(sp-15)=*os_context_register_addr(context,reg_R13);
972 *(sp-14)=*os_context_register_addr(context,reg_R12);
973 *(sp-13)=*os_context_register_addr(context,reg_R11);
974 *(sp-12)=*os_context_register_addr(context,reg_R10);
975 *(sp-11)=*os_context_register_addr(context,reg_R9);
976 *(sp-10)=*os_context_register_addr(context,reg_R8);
977 *(sp-9)=*os_context_register_addr(context,reg_RDI);
978 *(sp-8)=*os_context_register_addr(context,reg_RSI);
979 /* skip RBP and RSP */
980 *(sp-7)=*os_context_register_addr(context,reg_RBX);
981 *(sp-6)=*os_context_register_addr(context,reg_RDX);
982 *(sp-5)=*os_context_register_addr(context,reg_RCX);
983 *(sp-4)=*os_context_register_addr(context,reg_RAX);
984 *(sp-3)=*context_eflags_addr(context);
985 *(sp-2)=*os_context_register_addr(context,reg_RBP);
986 *(sp-1)=*os_context_pc_addr(context);
988 *os_context_register_addr(context,reg_RDI) =
989 (os_context_register_t)function; /* function */
990 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
991 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
993 struct thread *th=arch_os_get_current_thread();
994 build_fake_control_stack_frames(th,context);
997 #ifdef LISP_FEATURE_X86
999 #if !defined(LISP_FEATURE_DARWIN)
1000 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
1001 *os_context_register_addr(context,reg_ECX) = 0;
1002 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
1004 *os_context_register_addr(context,reg_UESP) =
1005 (os_context_register_t)(sp-15);
1007 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
1008 #endif /* __NETBSD__ */
1009 #endif /* LISP_FEATURE_DARWIN */
1011 #elif defined(LISP_FEATURE_X86_64)
1012 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
1013 *os_context_register_addr(context,reg_RCX) = 0;
1014 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
1015 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
1017 /* this much of the calling convention is common to all
1019 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
1020 *os_context_register_addr(context,reg_NARGS) = 0;
1021 *os_context_register_addr(context,reg_LIP) =
1022 (os_context_register_t)(unsigned long)code;
1023 *os_context_register_addr(context,reg_CFP) =
1024 (os_context_register_t)(unsigned long)current_control_frame_pointer;
1026 #ifdef ARCH_HAS_NPC_REGISTER
1027 *os_context_npc_addr(context) =
1028 4 + *os_context_pc_addr(context);
1030 #ifdef LISP_FEATURE_SPARC
1031 *os_context_register_addr(context,reg_CODE) =
1032 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
1034 FSHOW((stderr, "/arranged return to Lisp function (0x%lx)\n",
1038 #ifdef LISP_FEATURE_SB_THREAD
1040 /* FIXME: this function can go away when all lisp handlers are invoked
1041 * via arrange_return_to_lisp_function. */
1043 interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
1045 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
1047 FSHOW_SIGNAL((stderr,"/interrupt_thread_handler\n"));
1048 check_blockables_blocked_or_lose();
1050 /* let the handler enable interrupts again when it sees fit */
1051 sigaddset_deferrable(os_context_sigmask_addr(context));
1052 arrange_return_to_lisp_function(context,
1053 StaticSymbolFunction(RUN_INTERRUPTION));
1058 /* KLUDGE: Theoretically the approach we use for undefined alien
1059 * variables should work for functions as well, but on PPC/Darwin
1060 * we get bus error at bogus addresses instead, hence this workaround,
1061 * that has the added benefit of automatically discriminating between
1062 * functions and variables.
1065 undefined_alien_function(void)
1067 funcall0(StaticSymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
1071 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
1073 struct thread *th=arch_os_get_current_thread();
1075 /* note the os_context hackery here. When the signal handler returns,
1076 * it won't go back to what it was doing ... */
1077 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
1078 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1079 /* We hit the end of the control stack: disable guard page
1080 * protection so the error handler has some headroom, protect the
1081 * previous page so that we can catch returns from the guard page
1082 * and restore it. */
1083 corruption_warning_and_maybe_lose("Control stack exhausted");
1084 protect_control_stack_guard_page(0);
1085 protect_control_stack_return_guard_page(1);
1087 arrange_return_to_lisp_function
1088 (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
1091 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
1092 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1093 /* We're returning from the guard page: reprotect it, and
1094 * unprotect this one. This works even if we somehow missed
1095 * the return-guard-page, and hit it on our way to new
1096 * exhaustion instead. */
1097 protect_control_stack_guard_page(1);
1098 protect_control_stack_return_guard_page(0);
1101 else if (addr >= undefined_alien_address &&
1102 addr < undefined_alien_address + os_vm_page_size) {
1103 arrange_return_to_lisp_function
1104 (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
1111 * noise to install handlers
1114 #ifndef LISP_FEATURE_WIN32
1115 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1116 * they are blocked, in Linux 2.6 the default handler is invoked
1117 * instead that usually coredumps. One might hastily think that adding
1118 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1119 * the whole sa_mask is ignored and instead of not adding the signal
1120 * in question to the mask. That means if it's not blockable the
1121 * signal must be unblocked at the beginning of signal handlers.
1123 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1124 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1125 * will be unblocked in the sigmask during the signal handler. -- RMK
1128 static volatile int sigaction_nodefer_works = -1;
1130 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1131 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1134 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1136 sigset_t empty, current;
1138 sigemptyset(&empty);
1139 thread_sigmask(SIG_BLOCK, &empty, ¤t);
1140 /* There should be exactly two blocked signals: the two we added
1141 * to sa_mask when setting up the handler. NetBSD doesn't block
1142 * the signal we're handling when SA_NODEFER is set; Linux before
1143 * 2.6.13 or so also doesn't block the other signal when
1144 * SA_NODEFER is set. */
1145 for(i = 1; i < NSIG; i++)
1146 if (sigismember(¤t, i) !=
1147 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1148 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1149 sigaction_nodefer_works = 0;
1151 if (sigaction_nodefer_works == -1)
1152 sigaction_nodefer_works = 1;
1156 see_if_sigaction_nodefer_works(void)
1158 struct sigaction sa, old_sa;
1160 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1161 sa.sa_sigaction = sigaction_nodefer_test_handler;
1162 sigemptyset(&sa.sa_mask);
1163 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1164 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1165 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1166 /* Make sure no signals are blocked. */
1169 sigemptyset(&empty);
1170 thread_sigmask(SIG_SETMASK, &empty, 0);
1172 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1173 while (sigaction_nodefer_works == -1);
1174 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1177 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1178 #undef SA_NODEFER_TEST_KILL_SIGNAL
1181 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1185 sigemptyset(&unblock);
1186 sigaddset(&unblock, signal);
1187 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1188 interrupt_handle_now_handler(signal, info, void_context);
1192 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1196 sigemptyset(&unblock);
1197 sigaddset(&unblock, signal);
1198 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1199 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1203 undoably_install_low_level_interrupt_handler (int signal,
1204 interrupt_handler_t handler)
1206 struct sigaction sa;
1208 if (0 > signal || signal >= NSIG) {
1209 lose("bad signal number %d\n", signal);
1212 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1213 sa.sa_sigaction = handler;
1214 else if (sigismember(&deferrable_sigset,signal))
1215 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1216 /* The use of a trampoline appears to break the
1217 arch_os_get_context() workaround for SPARC/Linux. For now,
1218 don't use the trampoline (and so be vulnerable to the problems
1219 that SA_NODEFER is meant to solve. */
1220 #if !(defined(LISP_FEATURE_SPARC) && defined(LISP_FEATURE_LINUX))
1221 else if (!sigaction_nodefer_works &&
1222 !sigismember(&blockable_sigset, signal))
1223 sa.sa_sigaction = low_level_unblock_me_trampoline;
1226 sa.sa_sigaction = handler;
1228 sigcopyset(&sa.sa_mask, &blockable_sigset);
1229 sa.sa_flags = SA_SIGINFO | SA_RESTART
1230 | (sigaction_nodefer_works ? SA_NODEFER : 0);
1231 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1232 if((signal==SIG_MEMORY_FAULT)
1233 #ifdef SIG_INTERRUPT_THREAD
1234 || (signal==SIG_INTERRUPT_THREAD)
1237 sa.sa_flags |= SA_ONSTACK;
1240 sigaction(signal, &sa, NULL);
1241 interrupt_low_level_handlers[signal] =
1242 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1246 /* This is called from Lisp. */
1248 install_handler(int signal, void handler(int, siginfo_t*, void*))
1250 #ifndef LISP_FEATURE_WIN32
1251 struct sigaction sa;
1253 union interrupt_handler oldhandler;
1255 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1258 sigaddset(&new, signal);
1259 thread_sigmask(SIG_BLOCK, &new, &old);
1261 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1262 (unsigned int)interrupt_low_level_handlers[signal]));
1263 if (interrupt_low_level_handlers[signal]==0) {
1264 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1265 ARE_SAME_HANDLER(handler, SIG_IGN))
1266 sa.sa_sigaction = handler;
1267 else if (sigismember(&deferrable_sigset, signal))
1268 sa.sa_sigaction = maybe_now_maybe_later;
1269 else if (!sigaction_nodefer_works &&
1270 !sigismember(&blockable_sigset, signal))
1271 sa.sa_sigaction = unblock_me_trampoline;
1273 sa.sa_sigaction = interrupt_handle_now_handler;
1275 sigcopyset(&sa.sa_mask, &blockable_sigset);
1276 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1277 (sigaction_nodefer_works ? SA_NODEFER : 0);
1278 sigaction(signal, &sa, NULL);
1281 oldhandler = interrupt_handlers[signal];
1282 interrupt_handlers[signal].c = handler;
1284 thread_sigmask(SIG_SETMASK, &old, 0);
1286 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1288 return (unsigned long)oldhandler.lisp;
1290 /* Probably-wrong Win32 hack */
1295 /* This must not go through lisp as it's allowed anytime, even when on
1298 sigabrt_handler(int signal, siginfo_t *info, void *void_context)
1300 lose("SIGABRT received.\n");
1304 interrupt_init(void)
1306 #ifndef LISP_FEATURE_WIN32
1308 SHOW("entering interrupt_init()");
1309 see_if_sigaction_nodefer_works();
1310 sigemptyset(&deferrable_sigset);
1311 sigemptyset(&blockable_sigset);
1312 sigaddset_deferrable(&deferrable_sigset);
1313 sigaddset_blockable(&blockable_sigset);
1315 /* Set up high level handler information. */
1316 for (i = 0; i < NSIG; i++) {
1317 interrupt_handlers[i].c =
1318 /* (The cast here blasts away the distinction between
1319 * SA_SIGACTION-style three-argument handlers and
1320 * signal(..)-style one-argument handlers, which is OK
1321 * because it works to call the 1-argument form where the
1322 * 3-argument form is expected.) */
1323 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1325 undoably_install_low_level_interrupt_handler(SIGABRT, sigabrt_handler);
1326 SHOW("returning from interrupt_init()");
1330 #ifndef LISP_FEATURE_WIN32
1332 siginfo_code(siginfo_t *info)
1334 return info->si_code;
1336 os_vm_address_t current_memory_fault_address;
1339 lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr)
1341 /* FIXME: This is lossy: if we get another memory fault (eg. from
1342 * another thread) before lisp has read this, we lose the information.
1343 * However, since this is mostly informative, we'll live with that for
1344 * now -- some address is better then no address in this case.
1346 current_memory_fault_address = addr;
1347 /* To allow debugging memory faults in signal handlers and such. */
1348 corruption_warning_and_maybe_lose("Memory fault");
1349 arrange_return_to_lisp_function(context,
1350 StaticSymbolFunction(MEMORY_FAULT_ERROR));
1355 unhandled_trap_error(os_context_t *context)
1357 lispobj context_sap;
1358 fake_foreign_function_call(context);
1359 context_sap = alloc_sap(context);
1360 #ifndef LISP_FEATURE_WIN32
1361 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1363 funcall1(StaticSymbolFunction(UNHANDLED_TRAP_ERROR), context_sap);
1364 lose("UNHANDLED-TRAP-ERROR fell through");
1367 /* Common logic for trapping instructions. How we actually handle each
1368 * case is highly architecture dependent, but the overall shape is
1371 handle_trap(os_context_t *context, int trap)
1374 case trap_PendingInterrupt:
1375 FSHOW((stderr, "/<trap pending interrupt>\n"));
1376 arch_skip_instruction(context);
1377 interrupt_handle_pending(context);
1381 FSHOW((stderr, "/<trap error/cerror %d>\n", trap));
1382 interrupt_internal_error(context, trap==trap_Cerror);
1384 case trap_Breakpoint:
1385 arch_handle_breakpoint(context);
1387 case trap_FunEndBreakpoint:
1388 arch_handle_fun_end_breakpoint(context);
1390 #ifdef trap_AfterBreakpoint
1391 case trap_AfterBreakpoint:
1392 arch_handle_after_breakpoint(context);
1395 #ifdef trap_SingleStepAround
1396 case trap_SingleStepAround:
1397 case trap_SingleStepBefore:
1398 arch_handle_single_step_trap(context, trap);
1402 fake_foreign_function_call(context);
1403 lose("%%PRIMITIVE HALT called; the party is over.\n");
1405 unhandled_trap_error(context);