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 sigaddset_deferrable(sigset_t *s)
82 sigaddset(s, SIGQUIT);
83 sigaddset(s, SIGPIPE);
84 sigaddset(s, SIGALRM);
86 sigaddset(s, SIGTSTP);
87 sigaddset(s, SIGCHLD);
89 sigaddset(s, SIGXCPU);
90 sigaddset(s, SIGXFSZ);
91 sigaddset(s, SIGVTALRM);
92 sigaddset(s, SIGPROF);
93 sigaddset(s, SIGWINCH);
95 #if !((defined(LISP_FEATURE_DARWIN) || defined(LISP_FEATURE_FREEBSD)) && defined(LISP_FEATURE_SB_THREAD))
96 sigaddset(s, SIGUSR1);
97 sigaddset(s, SIGUSR2);
100 #ifdef LISP_FEATURE_SB_THREAD
101 sigaddset(s, SIG_INTERRUPT_THREAD);
106 sigaddset_blockable(sigset_t *s)
108 sigaddset_deferrable(s);
109 #ifdef LISP_FEATURE_SB_THREAD
110 #ifdef SIG_RESUME_FROM_GC
111 sigaddset(s, SIG_RESUME_FROM_GC);
113 sigaddset(s, SIG_STOP_FOR_GC);
117 /* initialized in interrupt_init */
118 static sigset_t deferrable_sigset;
119 static sigset_t blockable_sigset;
123 check_blockables_blocked_or_lose(void)
125 #if !defined(LISP_FEATURE_WIN32)
126 /* Get the current sigmask, by blocking the empty set. */
127 sigset_t empty,current;
130 thread_sigmask(SIG_BLOCK, &empty, ¤t);
131 for(i = 1; i < NSIG; i++) {
132 if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i))
133 lose("blockable signal %d not blocked\n",i);
139 unblock_gc_signals(void)
141 #ifdef LISP_FEATURE_SB_THREAD
144 #if defined(SIG_RESUME_FROM_GC)
145 sigaddset(&new,SIG_RESUME_FROM_GC);
147 sigaddset(&new,SIG_STOP_FOR_GC);
148 thread_sigmask(SIG_UNBLOCK,&new,0);
153 check_interrupts_enabled_or_lose(os_context_t *context)
155 struct thread *thread=arch_os_get_current_thread();
156 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
157 lose("interrupts not enabled\n");
158 if (arch_pseudo_atomic_atomic(context))
159 lose ("in pseudo atomic section\n");
162 /* When we catch an internal error, should we pass it back to Lisp to
163 * be handled in a high-level way? (Early in cold init, the answer is
164 * 'no', because Lisp is still too brain-dead to handle anything.
165 * After sufficient initialization has been completed, the answer
167 boolean internal_errors_enabled = 0;
169 #ifndef LISP_FEATURE_WIN32
170 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*);
172 union interrupt_handler interrupt_handlers[NSIG];
174 /* At the toplevel repl we routinely call this function. The signal
175 * mask ought to be clear anyway most of the time, but may be non-zero
176 * if we were interrupted e.g. while waiting for a queue. */
179 reset_signal_mask(void)
181 #ifndef LISP_FEATURE_WIN32
184 thread_sigmask(SIG_SETMASK,&new,0);
189 block_blockable_signals(void)
191 #ifndef LISP_FEATURE_WIN32
192 thread_sigmask(SIG_BLOCK, &blockable_sigset, 0);
197 block_deferrable_signals(void)
199 #ifndef LISP_FEATURE_WIN32
200 thread_sigmask(SIG_BLOCK, &deferrable_sigset, 0);
206 * utility routines used by various signal handlers
210 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
212 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
216 /* Build a fake stack frame or frames */
218 current_control_frame_pointer =
219 (lispobj *)(unsigned long)
220 (*os_context_register_addr(context, reg_CSP));
221 if ((lispobj *)(unsigned long)
222 (*os_context_register_addr(context, reg_CFP))
223 == current_control_frame_pointer) {
224 /* There is a small window during call where the callee's
225 * frame isn't built yet. */
226 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
227 == FUN_POINTER_LOWTAG) {
228 /* We have called, but not built the new frame, so
229 * build it for them. */
230 current_control_frame_pointer[0] =
231 *os_context_register_addr(context, reg_OCFP);
232 current_control_frame_pointer[1] =
233 *os_context_register_addr(context, reg_LRA);
234 current_control_frame_pointer += 8;
235 /* Build our frame on top of it. */
236 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
239 /* We haven't yet called, build our frame as if the
240 * partial frame wasn't there. */
241 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
244 /* We can't tell whether we are still in the caller if it had to
245 * allocate a stack frame due to stack arguments. */
246 /* This observation provoked some past CMUCL maintainer to ask
247 * "Can anything strange happen during return?" */
250 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
253 current_control_stack_pointer = current_control_frame_pointer + 8;
255 current_control_frame_pointer[0] = oldcont;
256 current_control_frame_pointer[1] = NIL;
257 current_control_frame_pointer[2] =
258 (lispobj)(*os_context_register_addr(context, reg_CODE));
262 /* Stores the context for gc to scavange and builds fake stack
265 fake_foreign_function_call(os_context_t *context)
268 struct thread *thread=arch_os_get_current_thread();
270 /* context_index incrementing must not be interrupted */
271 check_blockables_blocked_or_lose();
273 /* Get current Lisp state from context. */
275 dynamic_space_free_pointer =
276 (lispobj *)(unsigned long)
277 (*os_context_register_addr(context, reg_ALLOC));
278 /* fprintf(stderr,"dynamic_space_free_pointer: %p\n", dynamic_space_free_pointer); */
279 #if defined(LISP_FEATURE_ALPHA)
280 if ((long)dynamic_space_free_pointer & 1) {
281 lose("dead in fake_foreign_function_call, context = %x\n", context);
286 current_binding_stack_pointer =
287 (lispobj *)(unsigned long)
288 (*os_context_register_addr(context, reg_BSP));
291 build_fake_control_stack_frames(thread,context);
293 /* Do dynamic binding of the active interrupt context index
294 * and save the context in the context array. */
296 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
298 if (context_index >= MAX_INTERRUPTS) {
299 lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS);
302 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
303 make_fixnum(context_index + 1),thread);
305 thread->interrupt_contexts[context_index] = context;
307 #ifdef FOREIGN_FUNCTION_CALL_FLAG
308 foreign_function_call_active = 1;
312 /* blocks all blockable signals. If you are calling from a signal handler,
313 * the usual signal mask will be restored from the context when the handler
314 * finishes. Otherwise, be careful */
316 undo_fake_foreign_function_call(os_context_t *context)
318 struct thread *thread=arch_os_get_current_thread();
319 /* Block all blockable signals. */
320 block_blockable_signals();
322 #ifdef FOREIGN_FUNCTION_CALL_FLAG
323 foreign_function_call_active = 0;
326 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
330 /* Put the dynamic space free pointer back into the context. */
331 *os_context_register_addr(context, reg_ALLOC) =
332 (unsigned long) dynamic_space_free_pointer
333 | (*os_context_register_addr(context, reg_ALLOC)
336 ((unsigned long)(*os_context_register_addr(context, reg_ALLOC)) & ~LOWTAG_MASK)
337 | ((unsigned long) dynamic_space_free_pointer & LOWTAG_MASK);
342 /* a handler for the signal caused by execution of a trap opcode
343 * signalling an internal error */
345 interrupt_internal_error(os_context_t *context, boolean continuable)
349 fake_foreign_function_call(context);
351 if (!internal_errors_enabled) {
352 describe_internal_error(context);
353 /* There's no good way to recover from an internal error
354 * before the Lisp error handling mechanism is set up. */
355 lose("internal error too early in init, can't recover\n");
358 /* Allocate the SAP object while the interrupts are still
360 context_sap = alloc_sap(context);
362 #ifndef LISP_FEATURE_WIN32
363 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
366 SHOW("in interrupt_internal_error");
368 /* Display some rudimentary debugging information about the
369 * error, so that even if the Lisp error handler gets badly
370 * confused, we have a chance to determine what's going on. */
371 describe_internal_error(context);
373 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
374 continuable ? T : NIL);
376 undo_fake_foreign_function_call(context); /* blocks signals again */
378 arch_skip_instruction(context);
382 interrupt_handle_pending(os_context_t *context)
384 /* There are three ways we can get here. First, if an interrupt
385 * occurs within pseudo-atomic, it will be deferred, and we'll
386 * trap to here at the end of the pseudo-atomic block. Second, if
387 * the GC (in alloc()) decides that a GC is required, it will set
388 * *GC-PENDING* and pseudo-atomic-interrupted, and alloc() is
389 * always called from within pseudo-atomic, and thus we end up
390 * here again. Third, when calling GC-ON or at the end of a
391 * WITHOUT-GCING, MAYBE-HANDLE-PENDING-GC will trap to here if
392 * there is a pending GC. */
394 /* Win32 only needs to handle the GC cases (for now?) */
396 struct thread *thread;
398 /* Punt if in PA section, marking it as interrupted. This can
399 * happenat least if we pick up a GC request while in a
400 * WITHOUT-GCING with an outer PA -- it is not immediately clear
401 * to me that this should/could ever happen, but better safe then
402 * sorry. --NS 2007-05-15 */
403 if (arch_pseudo_atomic_atomic(context)) {
404 arch_set_pseudo_atomic_interrupted(context);
408 thread = arch_os_get_current_thread();
410 FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n"));
412 check_blockables_blocked_or_lose();
414 /* If pseudo_atomic_interrupted is set then the interrupt is going
415 * to be handled now, ergo it's safe to clear it. */
416 arch_clear_pseudo_atomic_interrupted(context);
418 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
419 #ifdef LISP_FEATURE_SB_THREAD
420 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
421 /* STOP_FOR_GC_PENDING and GC_PENDING are cleared by
422 * the signal handler if it actually stops us. */
423 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
426 if (SymbolValue(GC_PENDING,thread) != NIL) {
427 /* GC_PENDING is cleared in SUB-GC, or if another thread
428 * is doing a gc already we will get a SIG_STOP_FOR_GC and
429 * that will clear it. */
432 check_blockables_blocked_or_lose();
435 #ifndef LISP_FEATURE_WIN32
436 /* we may be here only to do the gc stuff, if interrupts are
437 * enabled run the pending handler */
438 if (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) {
439 struct interrupt_data *data = thread->interrupt_data;
441 /* There may be no pending handler, because it was only a gc
442 * that had to be executed or because pseudo atomic triggered
443 * twice for a single interrupt. For the interested reader,
444 * that may happen if an interrupt hits after the interrupted
445 * flag is cleared but before pseduo-atomic is set and a
446 * pseudo atomic is interrupted in that interrupt. */
447 if (data->pending_handler) {
449 /* If we're here as the result of a pseudo-atomic as opposed
450 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
451 * NIL, because maybe_defer_handler sets
452 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
453 SetSymbolValue(INTERRUPT_PENDING, NIL, thread);
455 /* restore the saved signal mask from the original signal (the
456 * one that interrupted us during the critical section) into the
457 * os_context for the signal we're currently in the handler for.
458 * This should ensure that when we return from the handler the
459 * blocked signals are unblocked */
460 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
462 sigemptyset(&data->pending_mask);
463 /* This will break on sparc linux: the deferred handler really wants
464 * to be called with a void_context */
465 run_deferred_handler(data,(void *)context);
472 * the two main signal handlers:
473 * interrupt_handle_now(..)
474 * maybe_now_maybe_later(..)
476 * to which we have added interrupt_handle_now_handler(..). Why?
477 * Well, mostly because the SPARC/Linux platform doesn't quite do
478 * signals the way we want them done. The third argument in the
479 * handler isn't filled in by the kernel properly, so we fix it up
480 * ourselves in the arch_os_get_context(..) function; however, we only
481 * want to do this when we first hit the handler, and not when
482 * interrupt_handle_now(..) is being called from some other handler
483 * (when the fixup will already have been done). -- CSR, 2002-07-23
487 interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
489 #ifdef FOREIGN_FUNCTION_CALL_FLAG
490 boolean were_in_lisp;
492 union interrupt_handler handler;
494 check_blockables_blocked_or_lose();
496 #ifndef LISP_FEATURE_WIN32
497 if (sigismember(&deferrable_sigset,signal))
498 check_interrupts_enabled_or_lose(context);
501 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
502 /* Under Linux on some architectures, we appear to have to restore
503 the FPU control word from the context, as after the signal is
504 delivered we appear to have a null FPU control word. */
505 os_restore_fp_control(context);
508 handler = interrupt_handlers[signal];
510 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
514 #ifdef FOREIGN_FUNCTION_CALL_FLAG
515 were_in_lisp = !foreign_function_call_active;
519 fake_foreign_function_call(context);
522 FSHOW_SIGNAL((stderr,
523 "/entering interrupt_handle_now(%d, info, context)\n",
526 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
528 /* This can happen if someone tries to ignore or default one
529 * of the signals we need for runtime support, and the runtime
530 * support decides to pass on it. */
531 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
533 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
534 /* Once we've decided what to do about contexts in a
535 * return-elsewhere world (the original context will no longer
536 * be available; should we copy it or was nobody using it anyway?)
537 * then we should convert this to return-elsewhere */
539 /* CMUCL comment said "Allocate the SAPs while the interrupts
540 * are still disabled.". I (dan, 2003.08.21) assume this is
541 * because we're not in pseudoatomic and allocation shouldn't
542 * be interrupted. In which case it's no longer an issue as
543 * all our allocation from C now goes through a PA wrapper,
544 * but still, doesn't hurt.
546 * Yeah, but non-gencgc platforms don't really wrap allocation
547 * in PA. MG - 2005-08-29 */
549 lispobj info_sap,context_sap = alloc_sap(context);
550 info_sap = alloc_sap(info);
551 /* Leave deferrable signals blocked, the handler itself will
552 * allow signals again when it sees fit. */
553 #ifdef LISP_FEATURE_SB_THREAD
556 sigemptyset(&unblock);
557 sigaddset(&unblock, SIG_STOP_FOR_GC);
558 #ifdef SIG_RESUME_FROM_GC
559 sigaddset(&unblock, SIG_RESUME_FROM_GC);
561 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
565 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
567 funcall3(handler.lisp,
573 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
575 #ifndef LISP_FEATURE_WIN32
576 /* Allow signals again. */
577 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
579 (*handler.c)(signal, info, context);
582 #ifdef FOREIGN_FUNCTION_CALL_FLAG
586 undo_fake_foreign_function_call(context); /* block signals again */
589 FSHOW_SIGNAL((stderr,
590 "/returning from interrupt_handle_now(%d, info, context)\n",
594 /* This is called at the end of a critical section if the indications
595 * are that some signal was deferred during the section. Note that as
596 * far as C or the kernel is concerned we dealt with the signal
597 * already; we're just doing the Lisp-level processing now that we
600 run_deferred_handler(struct interrupt_data *data, void *v_context) {
601 /* The pending_handler may enable interrupts and then another
602 * interrupt may hit, overwrite interrupt_data, so reset the
603 * pending handler before calling it. Trust the handler to finish
604 * with the siginfo before enabling interrupts. */
605 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
607 data->pending_handler=0;
608 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
611 #ifndef LISP_FEATURE_WIN32
613 maybe_defer_handler(void *handler, struct interrupt_data *data,
614 int signal, siginfo_t *info, os_context_t *context)
616 struct thread *thread=arch_os_get_current_thread();
618 check_blockables_blocked_or_lose();
620 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
621 lose("interrupt already pending\n");
622 /* If interrupts are disabled then INTERRUPT_PENDING is set and
623 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
624 * atomic section inside a WITHOUT-INTERRUPTS.
626 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
627 store_signal_data_for_later(data,handler,signal,info,context);
628 SetSymbolValue(INTERRUPT_PENDING, T,thread);
629 FSHOW_SIGNAL((stderr,
630 "/maybe_defer_handler(%x,%d),thread=%lu: deferred\n",
631 (unsigned int)handler,signal,
632 (unsigned long)thread->os_thread));
635 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
636 * actually use its argument for anything on x86, so this branch
637 * may succeed even when context is null (gencgc alloc()) */
638 if (arch_pseudo_atomic_atomic(context)) {
639 store_signal_data_for_later(data,handler,signal,info,context);
640 arch_set_pseudo_atomic_interrupted(context);
641 FSHOW_SIGNAL((stderr,
642 "/maybe_defer_handler(%x,%d),thread=%lu: deferred(PA)\n",
643 (unsigned int)handler,signal,
644 (unsigned long)thread->os_thread));
647 FSHOW_SIGNAL((stderr,
648 "/maybe_defer_handler(%x,%d),thread=%lu: not deferred\n",
649 (unsigned int)handler,signal,
650 (unsigned long)thread->os_thread));
655 store_signal_data_for_later (struct interrupt_data *data, void *handler,
657 siginfo_t *info, os_context_t *context)
659 if (data->pending_handler)
660 lose("tried to overwrite pending interrupt handler %x with %x\n",
661 data->pending_handler, handler);
663 lose("tried to defer null interrupt handler\n");
664 data->pending_handler = handler;
665 data->pending_signal = signal;
667 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
669 FSHOW_SIGNAL((stderr, "/store_signal_data_for_later: signal: %d\n", signal));
672 /* the signal mask in the context (from before we were
673 * interrupted) is copied to be restored when
674 * run_deferred_handler happens. Then the usually-blocked
675 * signals are added to the mask in the context so that we are
676 * running with blocked signals when the handler returns */
677 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
678 sigaddset_deferrable(os_context_sigmask_addr(context));
683 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
685 os_context_t *context = arch_os_get_context(&void_context);
686 struct thread *thread = arch_os_get_current_thread();
687 struct interrupt_data *data = thread->interrupt_data;
689 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
690 os_restore_fp_control(context);
693 if(!maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
694 interrupt_handle_now(signal, info, context);
696 #ifdef LISP_FEATURE_DARWIN
697 DARWIN_FIX_CONTEXT(context);
702 low_level_interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
704 /* No FP control fixage needed, caller has done that. */
705 check_blockables_blocked_or_lose();
706 check_interrupts_enabled_or_lose(context);
707 interrupt_low_level_handlers[signal](signal, info, context);
708 /* No Darwin context fixage needed, caller does that. */
712 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
714 os_context_t *context = arch_os_get_context(&void_context);
715 struct thread *thread = arch_os_get_current_thread();
716 struct interrupt_data *data = thread->interrupt_data;
718 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
719 os_restore_fp_control(context);
722 if(!maybe_defer_handler(low_level_interrupt_handle_now,data,
723 signal,info,context))
724 low_level_interrupt_handle_now(signal, info, context);
726 #ifdef LISP_FEATURE_DARWIN
727 DARWIN_FIX_CONTEXT(context);
732 #ifdef LISP_FEATURE_SB_THREAD
735 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
737 os_context_t *context = arch_os_get_context(&void_context);
739 struct thread *thread=arch_os_get_current_thread();
742 if (arch_pseudo_atomic_atomic(context)) {
743 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
744 arch_set_pseudo_atomic_interrupted(context);
745 FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred (PA)\n",
749 else if (SymbolValue(GC_INHIBIT,thread) != NIL) {
750 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
751 FSHOW_SIGNAL((stderr,
752 "thread=%lu sig_stop_for_gc deferred (*GC-INHIBIT*)\n",
757 /* Not PA and GC not inhibited -- we can stop now. */
759 /* need the context stored so it can have registers scavenged */
760 fake_foreign_function_call(context);
762 /* Block everything. */
764 thread_sigmask(SIG_BLOCK,&ss,0);
766 /* Not pending anymore. */
767 SetSymbolValue(GC_PENDING,NIL,thread);
768 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
770 if(thread->state!=STATE_RUNNING) {
771 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
772 fixnum_value(thread->state));
775 thread->state=STATE_SUSPENDED;
776 FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread));
778 #if defined(SIG_RESUME_FROM_GC)
779 sigemptyset(&ss); sigaddset(&ss,SIG_RESUME_FROM_GC);
781 sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
784 /* It is possible to get SIGCONT (and probably other non-blockable
786 #ifdef SIG_RESUME_FROM_GC
789 do { sigwait(&ss, &sigret); }
790 while (sigret != SIG_RESUME_FROM_GC);
793 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
796 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
797 if(thread->state!=STATE_RUNNING) {
798 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
799 fixnum_value(thread->state));
802 undo_fake_foreign_function_call(context);
807 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
809 os_context_t *context = arch_os_get_context(&void_context);
810 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
811 os_restore_fp_control(context);
813 interrupt_handle_now(signal, info, context);
814 #ifdef LISP_FEATURE_DARWIN
815 DARWIN_FIX_CONTEXT(context);
819 /* manipulate the signal context and stack such that when the handler
820 * returns, it will call function instead of whatever it was doing
824 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
825 extern int *context_eflags_addr(os_context_t *context);
828 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
829 extern void post_signal_tramp(void);
830 extern void call_into_lisp_tramp(void);
832 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
834 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
835 void * fun=native_pointer(function);
836 void *code = &(((struct simple_fun *) fun)->code);
839 /* Build a stack frame showing `interrupted' so that the
840 * user's backtrace makes (as much) sense (as usual) */
842 /* FIXME: what about restoring fp state? */
843 /* FIXME: what about restoring errno? */
844 #ifdef LISP_FEATURE_X86
845 /* Suppose the existence of some function that saved all
846 * registers, called call_into_lisp, then restored GP registers and
847 * returned. It would look something like this:
855 pushl {address of function to call}
856 call 0x8058db0 <call_into_lisp>
863 * What we do here is set up the stack that call_into_lisp would
864 * expect to see if it had been called by this code, and frob the
865 * signal context so that signal return goes directly to call_into_lisp,
866 * and when that function (and the lisp function it invoked) returns,
867 * it returns to the second half of this imaginary function which
868 * restores all registers and returns to C
870 * For this to work, the latter part of the imaginary function
871 * must obviously exist in reality. That would be post_signal_tramp
874 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
876 #if defined(LISP_FEATURE_DARWIN)
877 u32 *register_save_area = (u32 *)os_validate(0, 0x40);
879 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp));
880 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context));
882 /* 1. os_validate (malloc/mmap) register_save_block
883 * 2. copy register state into register_save_block
884 * 3. put a pointer to register_save_block in a register in the context
885 * 4. set the context's EIP to point to a trampoline which:
886 * a. builds the fake stack frame from the block
888 * c. calls the function
891 *register_save_area = *os_context_pc_addr(context);
892 *(register_save_area + 1) = function;
893 *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI);
894 *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI);
895 *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX);
896 *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX);
897 *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX);
898 *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX);
899 *(register_save_area + 8) = *context_eflags_addr(context);
901 *os_context_pc_addr(context) =
902 (os_context_register_t) call_into_lisp_tramp;
903 *os_context_register_addr(context,reg_ECX) =
904 (os_context_register_t) register_save_area;
907 /* return address for call_into_lisp: */
908 *(sp-15) = (u32)post_signal_tramp;
909 *(sp-14) = function; /* args for call_into_lisp : function*/
910 *(sp-13) = 0; /* arg array */
911 *(sp-12) = 0; /* no. args */
912 /* this order matches that used in POPAD */
913 *(sp-11)=*os_context_register_addr(context,reg_EDI);
914 *(sp-10)=*os_context_register_addr(context,reg_ESI);
916 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
917 /* POPAD ignores the value of ESP: */
919 *(sp-7)=*os_context_register_addr(context,reg_EBX);
921 *(sp-6)=*os_context_register_addr(context,reg_EDX);
922 *(sp-5)=*os_context_register_addr(context,reg_ECX);
923 *(sp-4)=*os_context_register_addr(context,reg_EAX);
924 *(sp-3)=*context_eflags_addr(context);
925 *(sp-2)=*os_context_register_addr(context,reg_EBP);
926 *(sp-1)=*os_context_pc_addr(context);
930 #elif defined(LISP_FEATURE_X86_64)
931 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
933 /* return address for call_into_lisp: */
934 *(sp-18) = (u64)post_signal_tramp;
936 *(sp-17)=*os_context_register_addr(context,reg_R15);
937 *(sp-16)=*os_context_register_addr(context,reg_R14);
938 *(sp-15)=*os_context_register_addr(context,reg_R13);
939 *(sp-14)=*os_context_register_addr(context,reg_R12);
940 *(sp-13)=*os_context_register_addr(context,reg_R11);
941 *(sp-12)=*os_context_register_addr(context,reg_R10);
942 *(sp-11)=*os_context_register_addr(context,reg_R9);
943 *(sp-10)=*os_context_register_addr(context,reg_R8);
944 *(sp-9)=*os_context_register_addr(context,reg_RDI);
945 *(sp-8)=*os_context_register_addr(context,reg_RSI);
946 /* skip RBP and RSP */
947 *(sp-7)=*os_context_register_addr(context,reg_RBX);
948 *(sp-6)=*os_context_register_addr(context,reg_RDX);
949 *(sp-5)=*os_context_register_addr(context,reg_RCX);
950 *(sp-4)=*os_context_register_addr(context,reg_RAX);
951 *(sp-3)=*context_eflags_addr(context);
952 *(sp-2)=*os_context_register_addr(context,reg_RBP);
953 *(sp-1)=*os_context_pc_addr(context);
955 *os_context_register_addr(context,reg_RDI) =
956 (os_context_register_t)function; /* function */
957 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
958 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
960 struct thread *th=arch_os_get_current_thread();
961 build_fake_control_stack_frames(th,context);
964 #ifdef LISP_FEATURE_X86
966 #if !defined(LISP_FEATURE_DARWIN)
967 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
968 *os_context_register_addr(context,reg_ECX) = 0;
969 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
971 *os_context_register_addr(context,reg_UESP) =
972 (os_context_register_t)(sp-15);
974 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
975 #endif /* __NETBSD__ */
976 #endif /* LISP_FEATURE_DARWIN */
978 #elif defined(LISP_FEATURE_X86_64)
979 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
980 *os_context_register_addr(context,reg_RCX) = 0;
981 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
982 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
984 /* this much of the calling convention is common to all
986 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
987 *os_context_register_addr(context,reg_NARGS) = 0;
988 *os_context_register_addr(context,reg_LIP) =
989 (os_context_register_t)(unsigned long)code;
990 *os_context_register_addr(context,reg_CFP) =
991 (os_context_register_t)(unsigned long)current_control_frame_pointer;
993 #ifdef ARCH_HAS_NPC_REGISTER
994 *os_context_npc_addr(context) =
995 4 + *os_context_pc_addr(context);
997 #ifdef LISP_FEATURE_SPARC
998 *os_context_register_addr(context,reg_CODE) =
999 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
1003 #ifdef LISP_FEATURE_SB_THREAD
1005 /* FIXME: this function can go away when all lisp handlers are invoked
1006 * via arrange_return_to_lisp_function. */
1008 interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
1010 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
1012 /* let the handler enable interrupts again when it sees fit */
1013 sigaddset_deferrable(os_context_sigmask_addr(context));
1014 arrange_return_to_lisp_function(context, SymbolFunction(RUN_INTERRUPTION));
1019 /* KLUDGE: Theoretically the approach we use for undefined alien
1020 * variables should work for functions as well, but on PPC/Darwin
1021 * we get bus error at bogus addresses instead, hence this workaround,
1022 * that has the added benefit of automatically discriminating between
1023 * functions and variables.
1026 undefined_alien_function() {
1027 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
1031 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
1033 struct thread *th=arch_os_get_current_thread();
1035 /* note the os_context hackery here. When the signal handler returns,
1036 * it won't go back to what it was doing ... */
1037 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
1038 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1039 /* We hit the end of the control stack: disable guard page
1040 * protection so the error handler has some headroom, protect the
1041 * previous page so that we can catch returns from the guard page
1042 * and restore it. */
1043 protect_control_stack_guard_page(0);
1044 protect_control_stack_return_guard_page(1);
1046 arrange_return_to_lisp_function
1047 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
1050 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
1051 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1052 /* We're returning from the guard page: reprotect it, and
1053 * unprotect this one. This works even if we somehow missed
1054 * the return-guard-page, and hit it on our way to new
1055 * exhaustion instead. */
1056 protect_control_stack_guard_page(1);
1057 protect_control_stack_return_guard_page(0);
1060 else if (addr >= undefined_alien_address &&
1061 addr < undefined_alien_address + os_vm_page_size) {
1062 arrange_return_to_lisp_function
1063 (context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
1070 * noise to install handlers
1073 #ifndef LISP_FEATURE_WIN32
1074 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1075 * they are blocked, in Linux 2.6 the default handler is invoked
1076 * instead that usually coredumps. One might hastily think that adding
1077 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1078 * the whole sa_mask is ignored and instead of not adding the signal
1079 * in question to the mask. That means if it's not blockable the
1080 * signal must be unblocked at the beginning of signal handlers.
1082 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1083 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1084 * will be unblocked in the sigmask during the signal handler. -- RMK
1087 static volatile int sigaction_nodefer_works = -1;
1089 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1090 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1093 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1095 sigset_t empty, current;
1097 sigemptyset(&empty);
1098 thread_sigmask(SIG_BLOCK, &empty, ¤t);
1099 /* There should be exactly two blocked signals: the two we added
1100 * to sa_mask when setting up the handler. NetBSD doesn't block
1101 * the signal we're handling when SA_NODEFER is set; Linux before
1102 * 2.6.13 or so also doesn't block the other signal when
1103 * SA_NODEFER is set. */
1104 for(i = 1; i < NSIG; i++)
1105 if (sigismember(¤t, i) !=
1106 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1107 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1108 sigaction_nodefer_works = 0;
1110 if (sigaction_nodefer_works == -1)
1111 sigaction_nodefer_works = 1;
1115 see_if_sigaction_nodefer_works()
1117 struct sigaction sa, old_sa;
1119 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1120 sa.sa_sigaction = sigaction_nodefer_test_handler;
1121 sigemptyset(&sa.sa_mask);
1122 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1123 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1124 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1125 /* Make sure no signals are blocked. */
1128 sigemptyset(&empty);
1129 thread_sigmask(SIG_SETMASK, &empty, 0);
1131 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1132 while (sigaction_nodefer_works == -1);
1133 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1136 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1137 #undef SA_NODEFER_TEST_KILL_SIGNAL
1140 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1144 sigemptyset(&unblock);
1145 sigaddset(&unblock, signal);
1146 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1147 interrupt_handle_now_handler(signal, info, void_context);
1151 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1155 sigemptyset(&unblock);
1156 sigaddset(&unblock, signal);
1157 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1158 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1162 undoably_install_low_level_interrupt_handler (int signal,
1163 interrupt_handler_t handler)
1165 struct sigaction sa;
1167 if (0 > signal || signal >= NSIG) {
1168 lose("bad signal number %d\n", signal);
1171 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1172 sa.sa_sigaction = handler;
1173 else if (sigismember(&deferrable_sigset,signal))
1174 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1175 /* The use of a trampoline appears to break the
1176 arch_os_get_context() workaround for SPARC/Linux. For now,
1177 don't use the trampoline (and so be vulnerable to the problems
1178 that SA_NODEFER is meant to solve. */
1179 #if !(defined(LISP_FEATURE_SPARC) && defined(LISP_FEATURE_LINUX))
1180 else if (!sigaction_nodefer_works &&
1181 !sigismember(&blockable_sigset, signal))
1182 sa.sa_sigaction = low_level_unblock_me_trampoline;
1185 sa.sa_sigaction = handler;
1187 sigcopyset(&sa.sa_mask, &blockable_sigset);
1188 sa.sa_flags = SA_SIGINFO | SA_RESTART
1189 | (sigaction_nodefer_works ? SA_NODEFER : 0);
1190 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1191 if((signal==SIG_MEMORY_FAULT)
1192 #ifdef SIG_MEMORY_FAULT2
1193 || (signal==SIG_MEMORY_FAULT2)
1195 #ifdef SIG_INTERRUPT_THREAD
1196 || (signal==SIG_INTERRUPT_THREAD)
1199 sa.sa_flags |= SA_ONSTACK;
1202 sigaction(signal, &sa, NULL);
1203 interrupt_low_level_handlers[signal] =
1204 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1208 /* This is called from Lisp. */
1210 install_handler(int signal, void handler(int, siginfo_t*, void*))
1212 #ifndef LISP_FEATURE_WIN32
1213 struct sigaction sa;
1215 union interrupt_handler oldhandler;
1217 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1220 sigaddset(&new, signal);
1221 thread_sigmask(SIG_BLOCK, &new, &old);
1223 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1224 (unsigned int)interrupt_low_level_handlers[signal]));
1225 if (interrupt_low_level_handlers[signal]==0) {
1226 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1227 ARE_SAME_HANDLER(handler, SIG_IGN))
1228 sa.sa_sigaction = handler;
1229 else if (sigismember(&deferrable_sigset, signal))
1230 sa.sa_sigaction = maybe_now_maybe_later;
1231 else if (!sigaction_nodefer_works &&
1232 !sigismember(&blockable_sigset, signal))
1233 sa.sa_sigaction = unblock_me_trampoline;
1235 sa.sa_sigaction = interrupt_handle_now_handler;
1237 sigcopyset(&sa.sa_mask, &blockable_sigset);
1238 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1239 (sigaction_nodefer_works ? SA_NODEFER : 0);
1240 sigaction(signal, &sa, NULL);
1243 oldhandler = interrupt_handlers[signal];
1244 interrupt_handlers[signal].c = handler;
1246 thread_sigmask(SIG_SETMASK, &old, 0);
1248 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1250 return (unsigned long)oldhandler.lisp;
1252 /* Probably-wrong Win32 hack */
1260 #ifndef LISP_FEATURE_WIN32
1262 SHOW("entering interrupt_init()");
1263 see_if_sigaction_nodefer_works();
1264 sigemptyset(&deferrable_sigset);
1265 sigemptyset(&blockable_sigset);
1266 sigaddset_deferrable(&deferrable_sigset);
1267 sigaddset_blockable(&blockable_sigset);
1269 /* Set up high level handler information. */
1270 for (i = 0; i < NSIG; i++) {
1271 interrupt_handlers[i].c =
1272 /* (The cast here blasts away the distinction between
1273 * SA_SIGACTION-style three-argument handlers and
1274 * signal(..)-style one-argument handlers, which is OK
1275 * because it works to call the 1-argument form where the
1276 * 3-argument form is expected.) */
1277 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1280 SHOW("returning from interrupt_init()");
1284 #ifndef LISP_FEATURE_WIN32
1286 siginfo_code(siginfo_t *info)
1288 return info->si_code;
1290 os_vm_address_t current_memory_fault_address;
1293 lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr)
1295 /* FIXME: This is lossy: if we get another memory fault (eg. from
1296 * another thread) before lisp has read this, we the information.
1297 * However, since this is mostly informative, we'll live with that for
1298 * now -- some address is better then no address in this case.
1300 current_memory_fault_address = addr;
1301 arrange_return_to_lisp_function(context, SymbolFunction(MEMORY_FAULT_ERROR));
1306 unhandled_trap_error(os_context_t *context)
1308 lispobj context_sap;
1309 fake_foreign_function_call(context);
1310 context_sap = alloc_sap(context);
1311 #ifndef LISP_FEATURE_WIN32
1312 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1314 funcall1(SymbolFunction(UNHANDLED_TRAP_ERROR), context_sap);
1315 lose("UNHANDLED-TRAP-ERROR fell through");
1318 /* Common logic far trapping instructions. How we actually handle each
1319 * case is highly architecture dependent, but the overall shape is
1322 handle_trap(os_context_t *context, int trap)
1325 case trap_PendingInterrupt:
1326 FSHOW((stderr, "/<trap pending interrupt>\n"));
1327 arch_skip_instruction(context);
1328 interrupt_handle_pending(context);
1332 FSHOW((stderr, "/<trap error/cerror %d>\n", trap));
1333 interrupt_internal_error(context, trap==trap_Cerror);
1335 case trap_Breakpoint:
1336 arch_handle_breakpoint(context);
1338 case trap_FunEndBreakpoint:
1339 arch_handle_fun_end_breakpoint(context);
1341 #ifdef trap_AfterBreakpoint
1342 case trap_AfterBreakpoint:
1343 arch_handle_after_breakpoint(context);
1346 #ifdef trap_SingleStepAround
1347 case trap_SingleStepAround:
1348 case trap_SingleStepBefore:
1349 arch_handle_single_step_trap(context, trap);
1353 fake_foreign_function_call(context);
1354 lose("%%PRIMITIVE HALT called; the party is over.\n");
1356 unhandled_trap_error(context);