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"
70 static void run_deferred_handler(struct interrupt_data *data, void *v_context);
71 #ifndef LISP_FEATURE_WIN32
72 static void store_signal_data_for_later (struct interrupt_data *data,
73 void *handler, int signal,
75 os_context_t *context);
78 fill_current_sigmask(sigset_t *sigset)
80 /* Get the current sigmask, by blocking the empty set. */
83 thread_sigmask(SIG_BLOCK, &empty, sigset);
87 sigaddset_deferrable(sigset_t *s)
91 sigaddset(s, SIGTERM);
92 sigaddset(s, SIGQUIT);
93 sigaddset(s, SIGPIPE);
94 sigaddset(s, SIGALRM);
96 sigaddset(s, SIGTSTP);
97 sigaddset(s, SIGCHLD);
99 #ifndef LISP_FEATURE_HPUX
100 sigaddset(s, SIGXCPU);
101 sigaddset(s, SIGXFSZ);
103 sigaddset(s, SIGVTALRM);
104 sigaddset(s, SIGPROF);
105 sigaddset(s, SIGWINCH);
107 #if !((defined(LISP_FEATURE_DARWIN) || defined(LISP_FEATURE_FREEBSD)) && defined(LISP_FEATURE_SB_THREAD))
108 sigaddset(s, SIGUSR1);
109 sigaddset(s, SIGUSR2);
112 #ifdef LISP_FEATURE_SB_THREAD
113 sigaddset(s, SIG_INTERRUPT_THREAD);
118 sigaddset_blockable(sigset_t *s)
120 sigaddset_deferrable(s);
121 #ifdef LISP_FEATURE_SB_THREAD
122 #ifdef SIG_RESUME_FROM_GC
123 sigaddset(s, SIG_RESUME_FROM_GC);
125 sigaddset(s, SIG_STOP_FOR_GC);
129 /* initialized in interrupt_init */
130 sigset_t deferrable_sigset;
131 sigset_t blockable_sigset;
135 check_deferrables_blocked_in_sigset_or_lose(sigset_t *sigset)
137 #if !defined(LISP_FEATURE_WIN32)
139 for(i = 1; i < NSIG; i++) {
140 if (sigismember(&deferrable_sigset, i) && !sigismember(sigset, i))
141 lose("deferrable signal %d not blocked\n",i);
147 check_deferrables_blocked_or_lose(void)
149 #if !defined(LISP_FEATURE_WIN32)
151 fill_current_sigmask(¤t);
152 check_deferrables_blocked_in_sigset_or_lose(¤t);
157 check_blockables_blocked_or_lose(void)
159 #if !defined(LISP_FEATURE_WIN32)
160 /* Get the current sigmask, by blocking the empty set. */
161 sigset_t empty,current;
164 thread_sigmask(SIG_BLOCK, &empty, ¤t);
165 for(i = 1; i < NSIG; i++) {
166 if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i))
167 lose("blockable signal %d not blocked\n",i);
173 unblock_gc_signals(void)
175 #ifdef LISP_FEATURE_SB_THREAD
178 #if defined(SIG_RESUME_FROM_GC)
179 sigaddset(&new,SIG_RESUME_FROM_GC);
181 sigaddset(&new,SIG_STOP_FOR_GC);
182 thread_sigmask(SIG_UNBLOCK,&new,0);
187 check_interrupts_enabled_or_lose(os_context_t *context)
189 struct thread *thread=arch_os_get_current_thread();
190 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
191 lose("interrupts not enabled\n");
192 if (arch_pseudo_atomic_atomic(context))
193 lose ("in pseudo atomic section\n");
196 /* When we catch an internal error, should we pass it back to Lisp to
197 * be handled in a high-level way? (Early in cold init, the answer is
198 * 'no', because Lisp is still too brain-dead to handle anything.
199 * After sufficient initialization has been completed, the answer
201 boolean internal_errors_enabled = 0;
203 #ifndef LISP_FEATURE_WIN32
204 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*);
206 union interrupt_handler interrupt_handlers[NSIG];
208 /* At the toplevel repl we routinely call this function. The signal
209 * mask ought to be clear anyway most of the time, but may be non-zero
210 * if we were interrupted e.g. while waiting for a queue. */
213 reset_signal_mask(void)
215 #ifndef LISP_FEATURE_WIN32
218 thread_sigmask(SIG_SETMASK,&new,0);
223 block_blockable_signals(void)
225 #ifndef LISP_FEATURE_WIN32
226 thread_sigmask(SIG_BLOCK, &blockable_sigset, 0);
231 block_deferrable_signals(void)
233 #ifndef LISP_FEATURE_WIN32
234 thread_sigmask(SIG_BLOCK, &deferrable_sigset, 0);
240 * utility routines used by various signal handlers
244 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
246 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
250 /* Build a fake stack frame or frames */
252 current_control_frame_pointer =
253 (lispobj *)(unsigned long)
254 (*os_context_register_addr(context, reg_CSP));
255 if ((lispobj *)(unsigned long)
256 (*os_context_register_addr(context, reg_CFP))
257 == current_control_frame_pointer) {
258 /* There is a small window during call where the callee's
259 * frame isn't built yet. */
260 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
261 == FUN_POINTER_LOWTAG) {
262 /* We have called, but not built the new frame, so
263 * build it for them. */
264 current_control_frame_pointer[0] =
265 *os_context_register_addr(context, reg_OCFP);
266 current_control_frame_pointer[1] =
267 *os_context_register_addr(context, reg_LRA);
268 current_control_frame_pointer += 8;
269 /* Build our frame on top of it. */
270 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
273 /* We haven't yet called, build our frame as if the
274 * partial frame wasn't there. */
275 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
278 /* We can't tell whether we are still in the caller if it had to
279 * allocate a stack frame due to stack arguments. */
280 /* This observation provoked some past CMUCL maintainer to ask
281 * "Can anything strange happen during return?" */
284 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
287 current_control_stack_pointer = current_control_frame_pointer + 8;
289 current_control_frame_pointer[0] = oldcont;
290 current_control_frame_pointer[1] = NIL;
291 current_control_frame_pointer[2] =
292 (lispobj)(*os_context_register_addr(context, reg_CODE));
296 /* Stores the context for gc to scavange and builds fake stack
299 fake_foreign_function_call(os_context_t *context)
302 struct thread *thread=arch_os_get_current_thread();
304 /* context_index incrementing must not be interrupted */
305 check_blockables_blocked_or_lose();
307 /* Get current Lisp state from context. */
309 dynamic_space_free_pointer =
310 (lispobj *)(unsigned long)
311 (*os_context_register_addr(context, reg_ALLOC));
312 /* fprintf(stderr,"dynamic_space_free_pointer: %p\n", */
313 /* dynamic_space_free_pointer); */
314 #if defined(LISP_FEATURE_ALPHA) || defined(LISP_FEATURE_MIPS)
315 if ((long)dynamic_space_free_pointer & 1) {
316 lose("dead in fake_foreign_function_call, context = %x\n", context);
319 /* why doesnt PPC and SPARC do something like this: */
320 #if defined(LISP_FEATURE_HPPA)
321 if ((long)dynamic_space_free_pointer & 4) {
322 lose("dead in fake_foreign_function_call, context = %x, d_s_f_p = %x\n", context, dynamic_space_free_pointer);
327 current_binding_stack_pointer =
328 (lispobj *)(unsigned long)
329 (*os_context_register_addr(context, reg_BSP));
332 build_fake_control_stack_frames(thread,context);
334 /* Do dynamic binding of the active interrupt context index
335 * and save the context in the context array. */
337 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
339 if (context_index >= MAX_INTERRUPTS) {
340 lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS);
343 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
344 make_fixnum(context_index + 1),thread);
346 thread->interrupt_contexts[context_index] = context;
348 #ifdef FOREIGN_FUNCTION_CALL_FLAG
349 foreign_function_call_active = 1;
353 /* blocks all blockable signals. If you are calling from a signal handler,
354 * the usual signal mask will be restored from the context when the handler
355 * finishes. Otherwise, be careful */
357 undo_fake_foreign_function_call(os_context_t *context)
359 struct thread *thread=arch_os_get_current_thread();
360 /* Block all blockable signals. */
361 block_blockable_signals();
363 #ifdef FOREIGN_FUNCTION_CALL_FLAG
364 foreign_function_call_active = 0;
367 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
371 /* Put the dynamic space free pointer back into the context. */
372 *os_context_register_addr(context, reg_ALLOC) =
373 (unsigned long) dynamic_space_free_pointer
374 | (*os_context_register_addr(context, reg_ALLOC)
377 ((unsigned long)(*os_context_register_addr(context, reg_ALLOC))
379 | ((unsigned long) dynamic_space_free_pointer & LOWTAG_MASK);
384 /* a handler for the signal caused by execution of a trap opcode
385 * signalling an internal error */
387 interrupt_internal_error(os_context_t *context, boolean continuable)
391 fake_foreign_function_call(context);
393 if (!internal_errors_enabled) {
394 describe_internal_error(context);
395 /* There's no good way to recover from an internal error
396 * before the Lisp error handling mechanism is set up. */
397 lose("internal error too early in init, can't recover\n");
400 /* Allocate the SAP object while the interrupts are still
402 context_sap = alloc_sap(context);
404 #ifndef LISP_FEATURE_WIN32
405 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
408 SHOW("in interrupt_internal_error");
410 /* Display some rudimentary debugging information about the
411 * error, so that even if the Lisp error handler gets badly
412 * confused, we have a chance to determine what's going on. */
413 describe_internal_error(context);
415 funcall2(StaticSymbolFunction(INTERNAL_ERROR), context_sap,
416 continuable ? T : NIL);
418 undo_fake_foreign_function_call(context); /* blocks signals again */
420 arch_skip_instruction(context);
424 interrupt_handle_pending(os_context_t *context)
426 /* There are three ways we can get here. First, if an interrupt
427 * occurs within pseudo-atomic, it will be deferred, and we'll
428 * trap to here at the end of the pseudo-atomic block. Second, if
429 * the GC (in alloc()) decides that a GC is required, it will set
430 * *GC-PENDING* and pseudo-atomic-interrupted if not *GC-INHIBIT*,
431 * and alloc() is always called from within pseudo-atomic, and
432 * thus we end up here again. Third, when calling GC-ON or at the
433 * end of a WITHOUT-GCING, MAYBE-HANDLE-PENDING-GC will trap to
434 * here if there is a pending GC. Fourth, ahem, at the end of
435 * WITHOUT-INTERRUPTS (bar complications with nesting). */
437 /* Win32 only needs to handle the GC cases (for now?) */
439 struct thread *thread;
441 if (arch_pseudo_atomic_atomic(context)) {
442 lose("Handling pending interrupt in pseduo atomic.");
445 thread = arch_os_get_current_thread();
447 FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n"));
449 check_blockables_blocked_or_lose();
451 /* If pseudo_atomic_interrupted is set then the interrupt is going
452 * to be handled now, ergo it's safe to clear it. */
453 arch_clear_pseudo_atomic_interrupted(context);
455 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
456 #ifdef LISP_FEATURE_SB_THREAD
457 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
458 /* STOP_FOR_GC_PENDING and GC_PENDING are cleared by
459 * the signal handler if it actually stops us. */
460 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
463 if (SymbolValue(GC_PENDING,thread) != NIL) {
464 /* GC_PENDING is cleared in SUB-GC, or if another thread
465 * is doing a gc already we will get a SIG_STOP_FOR_GC and
466 * that will clear it. */
469 check_blockables_blocked_or_lose();
472 #ifndef LISP_FEATURE_WIN32
473 /* we may be here only to do the gc stuff, if interrupts are
474 * enabled run the pending handler */
475 if (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) {
476 struct interrupt_data *data = thread->interrupt_data;
478 /* There may be no pending handler, because it was only a gc
479 * that had to be executed or because pseudo atomic triggered
480 * twice for a single interrupt. For the interested reader,
481 * that may happen if an interrupt hits after the interrupted
482 * flag is cleared but before pseudo-atomic is set and a
483 * pseudo atomic is interrupted in that interrupt. */
484 if (data->pending_handler) {
486 /* If we're here as the result of a pseudo-atomic as opposed
487 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
488 * NIL, because maybe_defer_handler sets
489 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
490 SetSymbolValue(INTERRUPT_PENDING, NIL, thread);
492 /* restore the saved signal mask from the original signal (the
493 * one that interrupted us during the critical section) into the
494 * os_context for the signal we're currently in the handler for.
495 * This should ensure that when we return from the handler the
496 * blocked signals are unblocked */
497 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
499 sigemptyset(&data->pending_mask);
500 /* This will break on sparc linux: the deferred handler really wants
501 * to be called with a void_context */
502 run_deferred_handler(data,(void *)context);
509 * the two main signal handlers:
510 * interrupt_handle_now(..)
511 * maybe_now_maybe_later(..)
513 * to which we have added interrupt_handle_now_handler(..). Why?
514 * Well, mostly because the SPARC/Linux platform doesn't quite do
515 * signals the way we want them done. The third argument in the
516 * handler isn't filled in by the kernel properly, so we fix it up
517 * ourselves in the arch_os_get_context(..) function; however, we only
518 * want to do this when we first hit the handler, and not when
519 * interrupt_handle_now(..) is being called from some other handler
520 * (when the fixup will already have been done). -- CSR, 2002-07-23
524 interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
526 #ifdef FOREIGN_FUNCTION_CALL_FLAG
527 boolean were_in_lisp;
529 union interrupt_handler handler;
531 check_blockables_blocked_or_lose();
533 #ifndef LISP_FEATURE_WIN32
534 if (sigismember(&deferrable_sigset,signal))
535 check_interrupts_enabled_or_lose(context);
538 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
539 /* Under Linux on some architectures, we appear to have to restore
540 the FPU control word from the context, as after the signal is
541 delivered we appear to have a null FPU control word. */
542 os_restore_fp_control(context);
545 handler = interrupt_handlers[signal];
547 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
551 #ifdef FOREIGN_FUNCTION_CALL_FLAG
552 were_in_lisp = !foreign_function_call_active;
556 fake_foreign_function_call(context);
559 FSHOW_SIGNAL((stderr,
560 "/entering interrupt_handle_now(%d, info, context)\n",
563 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
565 /* This can happen if someone tries to ignore or default one
566 * of the signals we need for runtime support, and the runtime
567 * support decides to pass on it. */
568 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
570 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
571 /* Once we've decided what to do about contexts in a
572 * return-elsewhere world (the original context will no longer
573 * be available; should we copy it or was nobody using it anyway?)
574 * then we should convert this to return-elsewhere */
576 /* CMUCL comment said "Allocate the SAPs while the interrupts
577 * are still disabled.". I (dan, 2003.08.21) assume this is
578 * because we're not in pseudoatomic and allocation shouldn't
579 * be interrupted. In which case it's no longer an issue as
580 * all our allocation from C now goes through a PA wrapper,
581 * but still, doesn't hurt.
583 * Yeah, but non-gencgc platforms don't really wrap allocation
584 * in PA. MG - 2005-08-29 */
586 lispobj info_sap,context_sap = alloc_sap(context);
587 info_sap = alloc_sap(info);
588 /* Leave deferrable signals blocked, the handler itself will
589 * allow signals again when it sees fit. */
590 #ifdef LISP_FEATURE_SB_THREAD
593 sigemptyset(&unblock);
594 sigaddset(&unblock, SIG_STOP_FOR_GC);
595 #ifdef SIG_RESUME_FROM_GC
596 sigaddset(&unblock, SIG_RESUME_FROM_GC);
598 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
602 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
604 funcall3(handler.lisp,
610 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
612 #ifndef LISP_FEATURE_WIN32
613 /* Allow signals again. */
614 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
616 (*handler.c)(signal, info, context);
619 #ifdef FOREIGN_FUNCTION_CALL_FLAG
623 undo_fake_foreign_function_call(context); /* block signals again */
626 FSHOW_SIGNAL((stderr,
627 "/returning from interrupt_handle_now(%d, info, context)\n",
631 /* This is called at the end of a critical section if the indications
632 * are that some signal was deferred during the section. Note that as
633 * far as C or the kernel is concerned we dealt with the signal
634 * already; we're just doing the Lisp-level processing now that we
637 run_deferred_handler(struct interrupt_data *data, void *v_context)
639 /* The pending_handler may enable interrupts and then another
640 * interrupt may hit, overwrite interrupt_data, so reset the
641 * pending handler before calling it. Trust the handler to finish
642 * with the siginfo before enabling interrupts. */
643 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
645 data->pending_handler=0;
646 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
649 #ifndef LISP_FEATURE_WIN32
651 maybe_defer_handler(void *handler, struct interrupt_data *data,
652 int signal, siginfo_t *info, os_context_t *context)
654 struct thread *thread=arch_os_get_current_thread();
656 check_blockables_blocked_or_lose();
658 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
659 lose("interrupt already pending\n");
660 /* If interrupts are disabled then INTERRUPT_PENDING is set and
661 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
662 * atomic section inside a WITHOUT-INTERRUPTS.
664 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
665 store_signal_data_for_later(data,handler,signal,info,context);
666 SetSymbolValue(INTERRUPT_PENDING, T,thread);
667 FSHOW_SIGNAL((stderr,
668 "/maybe_defer_handler(%x,%d): deferred\n",
669 (unsigned int)handler,signal));
672 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
673 * actually use its argument for anything on x86, so this branch
674 * may succeed even when context is null (gencgc alloc()) */
675 if (arch_pseudo_atomic_atomic(context)) {
676 store_signal_data_for_later(data,handler,signal,info,context);
677 arch_set_pseudo_atomic_interrupted(context);
678 FSHOW_SIGNAL((stderr,
679 "/maybe_defer_handler(%x,%d): deferred(PA)\n",
680 (unsigned int)handler,signal));
683 FSHOW_SIGNAL((stderr,
684 "/maybe_defer_handler(%x,%d): not deferred\n",
685 (unsigned int)handler,signal));
690 store_signal_data_for_later (struct interrupt_data *data, void *handler,
692 siginfo_t *info, os_context_t *context)
694 if (data->pending_handler)
695 lose("tried to overwrite pending interrupt handler %x with %x\n",
696 data->pending_handler, handler);
698 lose("tried to defer null interrupt handler\n");
699 data->pending_handler = handler;
700 data->pending_signal = signal;
702 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
704 FSHOW_SIGNAL((stderr, "/store_signal_data_for_later: signal: %d\n",
708 /* the signal mask in the context (from before we were
709 * interrupted) is copied to be restored when
710 * run_deferred_handler happens. Then the usually-blocked
711 * signals are added to the mask in the context so that we are
712 * running with blocked signals when the handler returns */
713 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
714 sigaddset_deferrable(os_context_sigmask_addr(context));
719 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
721 os_context_t *context = arch_os_get_context(&void_context);
722 struct thread *thread = arch_os_get_current_thread();
723 struct interrupt_data *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(interrupt_handle_now,data,signal,info,context))
730 interrupt_handle_now(signal, info, context);
734 low_level_interrupt_handle_now(int signal, siginfo_t *info,
735 os_context_t *context)
737 /* No FP control fixage needed, caller has done that. */
738 check_blockables_blocked_or_lose();
739 check_interrupts_enabled_or_lose(context);
740 (*interrupt_low_level_handlers[signal])(signal, info, context);
741 /* No Darwin context fixage needed, caller does that. */
745 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
747 os_context_t *context = arch_os_get_context(&void_context);
748 struct thread *thread = arch_os_get_current_thread();
749 struct interrupt_data *data = thread->interrupt_data;
751 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
752 os_restore_fp_control(context);
755 if(!maybe_defer_handler(low_level_interrupt_handle_now,data,
756 signal,info,context))
757 low_level_interrupt_handle_now(signal, info, context);
761 #ifdef LISP_FEATURE_SB_THREAD
764 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
766 os_context_t *context = arch_os_get_context(&void_context);
768 struct thread *thread=arch_os_get_current_thread();
771 if (arch_pseudo_atomic_atomic(context)) {
772 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
773 arch_set_pseudo_atomic_interrupted(context);
774 FSHOW_SIGNAL((stderr, "sig_stop_for_gc deferred (PA)\n"));
777 else if (SymbolValue(GC_INHIBIT,thread) != NIL) {
778 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
779 FSHOW_SIGNAL((stderr, "sig_stop_for_gc deferred (*GC-INHIBIT*)\n"));
783 /* Not PA and GC not inhibited -- we can stop now. */
785 /* need the context stored so it can have registers scavenged */
786 fake_foreign_function_call(context);
788 /* Block everything. */
790 thread_sigmask(SIG_BLOCK,&ss,0);
792 /* Not pending anymore. */
793 SetSymbolValue(GC_PENDING,NIL,thread);
794 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
796 if(thread->state!=STATE_RUNNING) {
797 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
798 fixnum_value(thread->state));
801 thread->state=STATE_SUSPENDED;
802 FSHOW_SIGNAL((stderr,"suspended\n"));
805 #if defined(SIG_RESUME_FROM_GC)
806 sigaddset(&ss,SIG_RESUME_FROM_GC);
808 sigaddset(&ss,SIG_STOP_FOR_GC);
811 /* It is possible to get SIGCONT (and probably other non-blockable
813 #ifdef SIG_RESUME_FROM_GC
816 do { sigwait(&ss, &sigret); }
817 while (sigret != SIG_RESUME_FROM_GC);
820 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
823 FSHOW_SIGNAL((stderr,"resumed\n"));
824 if(thread->state!=STATE_RUNNING) {
825 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
826 fixnum_value(thread->state));
829 undo_fake_foreign_function_call(context);
834 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
836 os_context_t *context = arch_os_get_context(&void_context);
837 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
838 os_restore_fp_control(context);
839 #ifndef LISP_FEATURE_WIN32
840 if ((signal == SIGILL) || (signal == SIGBUS)
841 #ifndef LISP_FEATURE_LINUX
842 || (signal == SIGEMT)
845 corruption_warning_and_maybe_lose("Signal %d recieved", signal);
848 interrupt_handle_now(signal, info, context);
851 /* manipulate the signal context and stack such that when the handler
852 * returns, it will call function instead of whatever it was doing
856 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
857 extern int *context_eflags_addr(os_context_t *context);
860 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
861 extern void post_signal_tramp(void);
862 extern void call_into_lisp_tramp(void);
864 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
866 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
867 void * fun=native_pointer(function);
868 void *code = &(((struct simple_fun *) fun)->code);
871 /* Build a stack frame showing `interrupted' so that the
872 * user's backtrace makes (as much) sense (as usual) */
874 /* FIXME: what about restoring fp state? */
875 /* FIXME: what about restoring errno? */
876 #ifdef LISP_FEATURE_X86
877 /* Suppose the existence of some function that saved all
878 * registers, called call_into_lisp, then restored GP registers and
879 * returned. It would look something like this:
887 pushl {address of function to call}
888 call 0x8058db0 <call_into_lisp>
895 * What we do here is set up the stack that call_into_lisp would
896 * expect to see if it had been called by this code, and frob the
897 * signal context so that signal return goes directly to call_into_lisp,
898 * and when that function (and the lisp function it invoked) returns,
899 * it returns to the second half of this imaginary function which
900 * restores all registers and returns to C
902 * For this to work, the latter part of the imaginary function
903 * must obviously exist in reality. That would be post_signal_tramp
906 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
908 #if defined(LISP_FEATURE_DARWIN)
909 u32 *register_save_area = (u32 *)os_validate(0, 0x40);
911 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp));
912 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context));
914 /* 1. os_validate (malloc/mmap) register_save_block
915 * 2. copy register state into register_save_block
916 * 3. put a pointer to register_save_block in a register in the context
917 * 4. set the context's EIP to point to a trampoline which:
918 * a. builds the fake stack frame from the block
920 * c. calls the function
923 *register_save_area = *os_context_pc_addr(context);
924 *(register_save_area + 1) = function;
925 *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI);
926 *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI);
927 *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX);
928 *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX);
929 *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX);
930 *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX);
931 *(register_save_area + 8) = *context_eflags_addr(context);
933 *os_context_pc_addr(context) =
934 (os_context_register_t) call_into_lisp_tramp;
935 *os_context_register_addr(context,reg_ECX) =
936 (os_context_register_t) register_save_area;
939 /* return address for call_into_lisp: */
940 *(sp-15) = (u32)post_signal_tramp;
941 *(sp-14) = function; /* args for call_into_lisp : function*/
942 *(sp-13) = 0; /* arg array */
943 *(sp-12) = 0; /* no. args */
944 /* this order matches that used in POPAD */
945 *(sp-11)=*os_context_register_addr(context,reg_EDI);
946 *(sp-10)=*os_context_register_addr(context,reg_ESI);
948 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
949 /* POPAD ignores the value of ESP: */
951 *(sp-7)=*os_context_register_addr(context,reg_EBX);
953 *(sp-6)=*os_context_register_addr(context,reg_EDX);
954 *(sp-5)=*os_context_register_addr(context,reg_ECX);
955 *(sp-4)=*os_context_register_addr(context,reg_EAX);
956 *(sp-3)=*context_eflags_addr(context);
957 *(sp-2)=*os_context_register_addr(context,reg_EBP);
958 *(sp-1)=*os_context_pc_addr(context);
962 #elif defined(LISP_FEATURE_X86_64)
963 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
965 /* return address for call_into_lisp: */
966 *(sp-18) = (u64)post_signal_tramp;
968 *(sp-17)=*os_context_register_addr(context,reg_R15);
969 *(sp-16)=*os_context_register_addr(context,reg_R14);
970 *(sp-15)=*os_context_register_addr(context,reg_R13);
971 *(sp-14)=*os_context_register_addr(context,reg_R12);
972 *(sp-13)=*os_context_register_addr(context,reg_R11);
973 *(sp-12)=*os_context_register_addr(context,reg_R10);
974 *(sp-11)=*os_context_register_addr(context,reg_R9);
975 *(sp-10)=*os_context_register_addr(context,reg_R8);
976 *(sp-9)=*os_context_register_addr(context,reg_RDI);
977 *(sp-8)=*os_context_register_addr(context,reg_RSI);
978 /* skip RBP and RSP */
979 *(sp-7)=*os_context_register_addr(context,reg_RBX);
980 *(sp-6)=*os_context_register_addr(context,reg_RDX);
981 *(sp-5)=*os_context_register_addr(context,reg_RCX);
982 *(sp-4)=*os_context_register_addr(context,reg_RAX);
983 *(sp-3)=*context_eflags_addr(context);
984 *(sp-2)=*os_context_register_addr(context,reg_RBP);
985 *(sp-1)=*os_context_pc_addr(context);
987 *os_context_register_addr(context,reg_RDI) =
988 (os_context_register_t)function; /* function */
989 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
990 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
992 struct thread *th=arch_os_get_current_thread();
993 build_fake_control_stack_frames(th,context);
996 #ifdef LISP_FEATURE_X86
998 #if !defined(LISP_FEATURE_DARWIN)
999 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
1000 *os_context_register_addr(context,reg_ECX) = 0;
1001 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
1003 *os_context_register_addr(context,reg_UESP) =
1004 (os_context_register_t)(sp-15);
1006 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
1007 #endif /* __NETBSD__ */
1008 #endif /* LISP_FEATURE_DARWIN */
1010 #elif defined(LISP_FEATURE_X86_64)
1011 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
1012 *os_context_register_addr(context,reg_RCX) = 0;
1013 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
1014 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
1016 /* this much of the calling convention is common to all
1018 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
1019 *os_context_register_addr(context,reg_NARGS) = 0;
1020 *os_context_register_addr(context,reg_LIP) =
1021 (os_context_register_t)(unsigned long)code;
1022 *os_context_register_addr(context,reg_CFP) =
1023 (os_context_register_t)(unsigned long)current_control_frame_pointer;
1025 #ifdef ARCH_HAS_NPC_REGISTER
1026 *os_context_npc_addr(context) =
1027 4 + *os_context_pc_addr(context);
1029 #ifdef LISP_FEATURE_SPARC
1030 *os_context_register_addr(context,reg_CODE) =
1031 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
1033 FSHOW((stderr, "/arranged return to Lisp function (0x%lx)\n",
1037 #ifdef LISP_FEATURE_SB_THREAD
1039 /* FIXME: this function can go away when all lisp handlers are invoked
1040 * via arrange_return_to_lisp_function. */
1042 interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
1044 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
1046 FSHOW_SIGNAL((stderr,"/interrupt_thread_handler\n"));
1047 check_blockables_blocked_or_lose();
1049 /* let the handler enable interrupts again when it sees fit */
1050 sigaddset_deferrable(os_context_sigmask_addr(context));
1051 arrange_return_to_lisp_function(context,
1052 StaticSymbolFunction(RUN_INTERRUPTION));
1057 /* KLUDGE: Theoretically the approach we use for undefined alien
1058 * variables should work for functions as well, but on PPC/Darwin
1059 * we get bus error at bogus addresses instead, hence this workaround,
1060 * that has the added benefit of automatically discriminating between
1061 * functions and variables.
1064 undefined_alien_function(void)
1066 funcall0(StaticSymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
1070 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
1072 struct thread *th=arch_os_get_current_thread();
1074 /* note the os_context hackery here. When the signal handler returns,
1075 * it won't go back to what it was doing ... */
1076 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
1077 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1078 /* We hit the end of the control stack: disable guard page
1079 * protection so the error handler has some headroom, protect the
1080 * previous page so that we can catch returns from the guard page
1081 * and restore it. */
1082 corruption_warning_and_maybe_lose("Control stack exhausted");
1083 protect_control_stack_guard_page(0);
1084 protect_control_stack_return_guard_page(1);
1086 arrange_return_to_lisp_function
1087 (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
1090 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
1091 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1092 /* We're returning from the guard page: reprotect it, and
1093 * unprotect this one. This works even if we somehow missed
1094 * the return-guard-page, and hit it on our way to new
1095 * exhaustion instead. */
1096 protect_control_stack_guard_page(1);
1097 protect_control_stack_return_guard_page(0);
1100 else if (addr >= undefined_alien_address &&
1101 addr < undefined_alien_address + os_vm_page_size) {
1102 arrange_return_to_lisp_function
1103 (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
1110 * noise to install handlers
1113 #ifndef LISP_FEATURE_WIN32
1114 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1115 * they are blocked, in Linux 2.6 the default handler is invoked
1116 * instead that usually coredumps. One might hastily think that adding
1117 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1118 * the whole sa_mask is ignored and instead of not adding the signal
1119 * in question to the mask. That means if it's not blockable the
1120 * signal must be unblocked at the beginning of signal handlers.
1122 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1123 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1124 * will be unblocked in the sigmask during the signal handler. -- RMK
1127 static volatile int sigaction_nodefer_works = -1;
1129 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1130 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1133 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1135 sigset_t empty, current;
1137 sigemptyset(&empty);
1138 thread_sigmask(SIG_BLOCK, &empty, ¤t);
1139 /* There should be exactly two blocked signals: the two we added
1140 * to sa_mask when setting up the handler. NetBSD doesn't block
1141 * the signal we're handling when SA_NODEFER is set; Linux before
1142 * 2.6.13 or so also doesn't block the other signal when
1143 * SA_NODEFER is set. */
1144 for(i = 1; i < NSIG; i++)
1145 if (sigismember(¤t, i) !=
1146 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1147 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1148 sigaction_nodefer_works = 0;
1150 if (sigaction_nodefer_works == -1)
1151 sigaction_nodefer_works = 1;
1155 see_if_sigaction_nodefer_works(void)
1157 struct sigaction sa, old_sa;
1159 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1160 sa.sa_sigaction = sigaction_nodefer_test_handler;
1161 sigemptyset(&sa.sa_mask);
1162 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1163 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1164 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1165 /* Make sure no signals are blocked. */
1168 sigemptyset(&empty);
1169 thread_sigmask(SIG_SETMASK, &empty, 0);
1171 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1172 while (sigaction_nodefer_works == -1);
1173 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1176 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1177 #undef SA_NODEFER_TEST_KILL_SIGNAL
1180 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1184 sigemptyset(&unblock);
1185 sigaddset(&unblock, signal);
1186 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1187 interrupt_handle_now_handler(signal, info, void_context);
1191 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1195 sigemptyset(&unblock);
1196 sigaddset(&unblock, signal);
1197 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1198 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1202 undoably_install_low_level_interrupt_handler (int signal,
1203 interrupt_handler_t handler)
1205 struct sigaction sa;
1207 if (0 > signal || signal >= NSIG) {
1208 lose("bad signal number %d\n", signal);
1211 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1212 sa.sa_sigaction = handler;
1213 else if (sigismember(&deferrable_sigset,signal))
1214 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1215 /* The use of a trampoline appears to break the
1216 arch_os_get_context() workaround for SPARC/Linux. For now,
1217 don't use the trampoline (and so be vulnerable to the problems
1218 that SA_NODEFER is meant to solve. */
1219 #if !(defined(LISP_FEATURE_SPARC) && defined(LISP_FEATURE_LINUX))
1220 else if (!sigaction_nodefer_works &&
1221 !sigismember(&blockable_sigset, signal))
1222 sa.sa_sigaction = low_level_unblock_me_trampoline;
1225 sa.sa_sigaction = handler;
1227 sigcopyset(&sa.sa_mask, &blockable_sigset);
1228 sa.sa_flags = SA_SIGINFO | SA_RESTART
1229 | (sigaction_nodefer_works ? SA_NODEFER : 0);
1230 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1231 if((signal==SIG_MEMORY_FAULT)
1232 #ifdef SIG_INTERRUPT_THREAD
1233 || (signal==SIG_INTERRUPT_THREAD)
1236 sa.sa_flags |= SA_ONSTACK;
1239 sigaction(signal, &sa, NULL);
1240 interrupt_low_level_handlers[signal] =
1241 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1245 /* This is called from Lisp. */
1247 install_handler(int signal, void handler(int, siginfo_t*, void*))
1249 #ifndef LISP_FEATURE_WIN32
1250 struct sigaction sa;
1252 union interrupt_handler oldhandler;
1254 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1257 sigaddset(&new, signal);
1258 thread_sigmask(SIG_BLOCK, &new, &old);
1260 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1261 (unsigned int)interrupt_low_level_handlers[signal]));
1262 if (interrupt_low_level_handlers[signal]==0) {
1263 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1264 ARE_SAME_HANDLER(handler, SIG_IGN))
1265 sa.sa_sigaction = handler;
1266 else if (sigismember(&deferrable_sigset, signal))
1267 sa.sa_sigaction = maybe_now_maybe_later;
1268 else if (!sigaction_nodefer_works &&
1269 !sigismember(&blockable_sigset, signal))
1270 sa.sa_sigaction = unblock_me_trampoline;
1272 sa.sa_sigaction = interrupt_handle_now_handler;
1274 sigcopyset(&sa.sa_mask, &blockable_sigset);
1275 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1276 (sigaction_nodefer_works ? SA_NODEFER : 0);
1277 sigaction(signal, &sa, NULL);
1280 oldhandler = interrupt_handlers[signal];
1281 interrupt_handlers[signal].c = handler;
1283 thread_sigmask(SIG_SETMASK, &old, 0);
1285 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1287 return (unsigned long)oldhandler.lisp;
1289 /* Probably-wrong Win32 hack */
1294 /* This must not go through lisp as it's allowed anytime, even when on
1297 sigabrt_handler(int signal, siginfo_t *info, void *void_context)
1299 lose("SIGABRT received.\n");
1303 interrupt_init(void)
1305 #ifndef LISP_FEATURE_WIN32
1307 SHOW("entering interrupt_init()");
1308 see_if_sigaction_nodefer_works();
1309 sigemptyset(&deferrable_sigset);
1310 sigemptyset(&blockable_sigset);
1311 sigaddset_deferrable(&deferrable_sigset);
1312 sigaddset_blockable(&blockable_sigset);
1314 /* Set up high level handler information. */
1315 for (i = 0; i < NSIG; i++) {
1316 interrupt_handlers[i].c =
1317 /* (The cast here blasts away the distinction between
1318 * SA_SIGACTION-style three-argument handlers and
1319 * signal(..)-style one-argument handlers, which is OK
1320 * because it works to call the 1-argument form where the
1321 * 3-argument form is expected.) */
1322 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1324 undoably_install_low_level_interrupt_handler(SIGABRT, sigabrt_handler);
1325 SHOW("returning from interrupt_init()");
1329 #ifndef LISP_FEATURE_WIN32
1331 siginfo_code(siginfo_t *info)
1333 return info->si_code;
1335 os_vm_address_t current_memory_fault_address;
1338 lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr)
1340 /* FIXME: This is lossy: if we get another memory fault (eg. from
1341 * another thread) before lisp has read this, we lose the information.
1342 * However, since this is mostly informative, we'll live with that for
1343 * now -- some address is better then no address in this case.
1345 current_memory_fault_address = addr;
1346 /* To allow debugging memory faults in signal handlers and such. */
1347 corruption_warning_and_maybe_lose("Memory fault");
1348 arrange_return_to_lisp_function(context,
1349 StaticSymbolFunction(MEMORY_FAULT_ERROR));
1354 unhandled_trap_error(os_context_t *context)
1356 lispobj context_sap;
1357 fake_foreign_function_call(context);
1358 context_sap = alloc_sap(context);
1359 #ifndef LISP_FEATURE_WIN32
1360 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1362 funcall1(StaticSymbolFunction(UNHANDLED_TRAP_ERROR), context_sap);
1363 lose("UNHANDLED-TRAP-ERROR fell through");
1366 /* Common logic for trapping instructions. How we actually handle each
1367 * case is highly architecture dependent, but the overall shape is
1370 handle_trap(os_context_t *context, int trap)
1373 case trap_PendingInterrupt:
1374 FSHOW((stderr, "/<trap pending interrupt>\n"));
1375 arch_skip_instruction(context);
1376 interrupt_handle_pending(context);
1380 FSHOW((stderr, "/<trap error/cerror %d>\n", trap));
1381 interrupt_internal_error(context, trap==trap_Cerror);
1383 case trap_Breakpoint:
1384 arch_handle_breakpoint(context);
1386 case trap_FunEndBreakpoint:
1387 arch_handle_fun_end_breakpoint(context);
1389 #ifdef trap_AfterBreakpoint
1390 case trap_AfterBreakpoint:
1391 arch_handle_after_breakpoint(context);
1394 #ifdef trap_SingleStepAround
1395 case trap_SingleStepAround:
1396 case trap_SingleStepBefore:
1397 arch_handle_single_step_trap(context, trap);
1401 fake_foreign_function_call(context);
1402 lose("%%PRIMITIVE HALT called; the party is over.\n");
1404 unhandled_trap_error(context);