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 /* Under Linux on some architectures, we appear to have to restore the
72 * FPU control word from the context, as after the signal is delivered
73 * we appear to have a null FPU control word. */
74 #if defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
75 #define RESTORE_FP_CONTROL_WORD(context,void_context) \
76 os_context_t *context = arch_os_get_context(&void_context); \
77 os_restore_fp_control(context);
79 #define RESTORE_FP_CONTROL_WORD(context,void_context) \
80 os_context_t *context = arch_os_get_context(&void_context);
83 /* These are to be used in signal handlers. Currently all handlers are
86 * interrupt_handle_now_handler
87 * maybe_now_maybe_later
88 * unblock_me_trampoline
89 * low_level_handle_now_handler
90 * low_level_maybe_now_maybe_later
91 * low_level_unblock_me_trampoline
93 * This gives us a single point of control (or six) over errno, fp
94 * control word, and fixing up signal context on sparc.
96 * The SPARC/Linux platform doesn't quite do signals the way we want
97 * them done. The third argument in the handler isn't filled in by the
98 * kernel properly, so we fix it up ourselves in the
99 * arch_os_get_context(..) function. -- CSR, 2002-07-23
101 #define SAVE_ERRNO(context,void_context) \
103 int _saved_errno = errno; \
104 RESTORE_FP_CONTROL_WORD(context,void_context); \
107 #define RESTORE_ERRNO \
109 errno = _saved_errno; \
112 static void run_deferred_handler(struct interrupt_data *data,
113 os_context_t *context);
114 #ifndef LISP_FEATURE_WIN32
115 static void store_signal_data_for_later (struct interrupt_data *data,
116 void *handler, int signal,
118 os_context_t *context);
121 /* Generic signal related utilities. */
124 get_current_sigmask(sigset_t *sigset)
126 /* Get the current sigmask, by blocking the empty set. */
127 thread_sigmask(SIG_BLOCK, 0, sigset);
131 block_signals(sigset_t *what, sigset_t *where, sigset_t *old)
136 sigcopyset(old, where);
137 for(i = 1; i < NSIG; i++) {
138 if (sigismember(what, i))
142 thread_sigmask(SIG_BLOCK, what, old);
147 unblock_signals(sigset_t *what, sigset_t *where, sigset_t *old)
152 sigcopyset(old, where);
153 for(i = 1; i < NSIG; i++) {
154 if (sigismember(what, i))
158 thread_sigmask(SIG_UNBLOCK, what, old);
163 print_sigset(sigset_t *sigset)
166 for(i = 1; i < NSIG; i++) {
167 if (sigismember(sigset, i))
168 fprintf(stderr, "Signal %d masked\n", i);
172 /* Return 1 is all signals is sigset2 are masked in sigset, return 0
173 * if all re unmasked else die. Passing NULL for sigset is a shorthand
174 * for the current sigmask. */
176 all_signals_blocked_p(sigset_t *sigset, sigset_t *sigset2,
179 #if !defined(LISP_FEATURE_WIN32)
181 boolean has_blocked = 0, has_unblocked = 0;
184 get_current_sigmask(¤t);
187 for(i = 1; i < NSIG; i++) {
188 if (sigismember(sigset2, i)) {
189 if (sigismember(sigset, i))
195 if (has_blocked && has_unblocked) {
196 print_sigset(sigset);
197 lose("some %s signals blocked, some unblocked\n", name);
207 /* Deferrables, blockables, gc signals. */
210 sigaddset_deferrable(sigset_t *s)
212 sigaddset(s, SIGHUP);
213 sigaddset(s, SIGINT);
214 sigaddset(s, SIGTERM);
215 sigaddset(s, SIGQUIT);
216 sigaddset(s, SIGPIPE);
217 sigaddset(s, SIGALRM);
218 sigaddset(s, SIGURG);
219 sigaddset(s, SIGTSTP);
220 sigaddset(s, SIGCHLD);
222 #ifndef LISP_FEATURE_HPUX
223 sigaddset(s, SIGXCPU);
224 sigaddset(s, SIGXFSZ);
226 sigaddset(s, SIGVTALRM);
227 sigaddset(s, SIGPROF);
228 sigaddset(s, SIGWINCH);
232 sigaddset_blockable(sigset_t *sigset)
234 sigaddset_deferrable(sigset);
235 sigaddset_gc(sigset);
239 sigaddset_gc(sigset_t *sigset)
241 #ifdef LISP_FEATURE_SB_THREAD
242 sigaddset(sigset,SIG_STOP_FOR_GC);
246 /* initialized in interrupt_init */
247 sigset_t deferrable_sigset;
248 sigset_t blockable_sigset;
254 deferrables_blocked_p(sigset_t *sigset)
256 return all_signals_blocked_p(sigset, &deferrable_sigset, "deferrable");
260 check_deferrables_unblocked_or_lose(sigset_t *sigset)
262 #if !defined(LISP_FEATURE_WIN32)
263 if (deferrables_blocked_p(sigset))
264 lose("deferrables blocked\n");
269 check_deferrables_blocked_or_lose(sigset_t *sigset)
271 #if !defined(LISP_FEATURE_WIN32)
272 if (!deferrables_blocked_p(sigset))
273 lose("deferrables unblocked\n");
278 blockables_blocked_p(sigset_t *sigset)
280 return all_signals_blocked_p(sigset, &blockable_sigset, "blockable");
284 check_blockables_unblocked_or_lose(sigset_t *sigset)
286 #if !defined(LISP_FEATURE_WIN32)
287 if (blockables_blocked_p(sigset))
288 lose("blockables blocked\n");
293 check_blockables_blocked_or_lose(sigset_t *sigset)
295 #if !defined(LISP_FEATURE_WIN32)
296 if (!blockables_blocked_p(sigset))
297 lose("blockables unblocked\n");
302 gc_signals_blocked_p(sigset_t *sigset)
304 return all_signals_blocked_p(sigset, &gc_sigset, "gc");
308 check_gc_signals_unblocked_or_lose(sigset_t *sigset)
310 #if !defined(LISP_FEATURE_WIN32)
311 if (gc_signals_blocked_p(sigset))
312 lose("gc signals blocked\n");
317 check_gc_signals_blocked_or_lose(sigset_t *sigset)
319 #if !defined(LISP_FEATURE_WIN32)
320 if (!gc_signals_blocked_p(sigset))
321 lose("gc signals unblocked\n");
326 block_deferrable_signals(sigset_t *where, sigset_t *old)
328 #ifndef LISP_FEATURE_WIN32
329 block_signals(&deferrable_sigset, where, old);
334 block_blockable_signals(sigset_t *where, sigset_t *old)
336 #ifndef LISP_FEATURE_WIN32
337 block_signals(&blockable_sigset, where, old);
342 block_gc_signals(sigset_t *where, sigset_t *old)
344 #ifndef LISP_FEATURE_WIN32
345 block_signals(&gc_sigset, where, old);
350 unblock_deferrable_signals(sigset_t *where, sigset_t *old)
352 #ifndef LISP_FEATURE_WIN32
353 if (interrupt_handler_pending_p())
354 lose("unblock_deferrable_signals: losing proposition\n");
355 check_gc_signals_unblocked_or_lose(where);
356 unblock_signals(&deferrable_sigset, where, old);
361 unblock_blockable_signals(sigset_t *where, sigset_t *old)
363 #ifndef LISP_FEATURE_WIN32
364 unblock_signals(&blockable_sigset, where, old);
369 unblock_gc_signals(sigset_t *where, sigset_t *old)
371 #ifndef LISP_FEATURE_WIN32
372 unblock_signals(&gc_sigset, where, old);
377 unblock_signals_in_context_and_maybe_warn(os_context_t *context)
379 #ifndef LISP_FEATURE_WIN32
380 sigset_t *sigset = os_context_sigmask_addr(context);
381 if (all_signals_blocked_p(sigset, &gc_sigset, "gc")) {
382 corruption_warning_and_maybe_lose(
383 "Enabling blocked gc signals to allow returning to Lisp without risking\n\
384 gc deadlocks. Since GC signals are only blocked in signal handlers when \n\
385 they are not safe to interrupt at all, this is a pretty severe occurrence.\n");
386 unblock_gc_signals(sigset, 0);
388 if (!interrupt_handler_pending_p()) {
389 unblock_deferrable_signals(sigset, 0);
396 check_interrupts_enabled_or_lose(os_context_t *context)
398 struct thread *thread=arch_os_get_current_thread();
399 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
400 lose("interrupts not enabled\n");
401 if (arch_pseudo_atomic_atomic(context))
402 lose ("in pseudo atomic section\n");
405 /* Save sigset (or the current sigmask if 0) if there is no pending
406 * handler, because that means that deferabbles are already blocked.
407 * The purpose is to avoid losing the pending gc signal if a
408 * deferrable interrupt async unwinds between clearing the pseudo
409 * atomic and trapping to GC.*/
411 maybe_save_gc_mask_and_block_deferrables(sigset_t *sigset)
413 #ifndef LISP_FEATURE_WIN32
414 struct thread *thread = arch_os_get_current_thread();
415 struct interrupt_data *data = thread->interrupt_data;
417 /* Obviously, this function is called when signals may not be
418 * blocked. Let's make sure we are not interrupted. */
419 block_blockable_signals(0, &oldset);
420 #ifndef LISP_FEATURE_SB_THREAD
421 /* With threads a SIG_STOP_FOR_GC and a normal GC may also want to
423 if (data->gc_blocked_deferrables)
424 lose("gc_blocked_deferrables already true\n");
426 if ((!data->pending_handler) &&
427 (!data->gc_blocked_deferrables)) {
428 FSHOW_SIGNAL((stderr,"/setting gc_blocked_deferrables\n"));
429 data->gc_blocked_deferrables = 1;
431 /* This is the sigmask of some context. */
432 sigcopyset(&data->pending_mask, sigset);
433 sigaddset_deferrable(sigset);
434 thread_sigmask(SIG_SETMASK,&oldset,0);
437 /* Operating on the current sigmask. Save oldset and
438 * unblock gc signals. In the end, this is equivalent to
439 * blocking the deferrables. */
440 sigcopyset(&data->pending_mask, &oldset);
441 thread_sigmask(SIG_UNBLOCK, &gc_sigset, 0);
445 thread_sigmask(SIG_SETMASK,&oldset,0);
449 /* Are we leaving WITH-GCING and already running with interrupts
450 * enabled, without the protection of *GC-INHIBIT* T and there is gc
451 * (or stop for gc) pending, but we haven't trapped yet? */
453 in_leaving_without_gcing_race_p(struct thread *thread)
455 return ((SymbolValue(IN_WITHOUT_GCING,thread) != NIL) &&
456 (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) &&
457 (SymbolValue(GC_INHIBIT,thread) == NIL) &&
458 ((SymbolValue(GC_PENDING,thread) != NIL)
459 #if defined(LISP_FEATURE_SB_THREAD)
460 || (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL)
465 /* Check our baroque invariants. */
467 check_interrupt_context_or_lose(os_context_t *context)
469 #ifndef LISP_FEATURE_WIN32
470 struct thread *thread = arch_os_get_current_thread();
471 struct interrupt_data *data = thread->interrupt_data;
472 int interrupt_deferred_p = (data->pending_handler != 0);
473 int interrupt_pending = (SymbolValue(INTERRUPT_PENDING,thread) != NIL);
474 sigset_t *sigset = os_context_sigmask_addr(context);
475 /* On PPC pseudo_atomic_interrupted is cleared when coming out of
476 * handle_allocation_trap. */
477 #if defined(LISP_FEATURE_GENCGC) && !defined(LISP_FEATURE_PPC)
478 int interrupts_enabled = (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL);
479 int gc_inhibit = (SymbolValue(GC_INHIBIT,thread) != NIL);
480 int gc_pending = (SymbolValue(GC_PENDING,thread) == T);
481 int pseudo_atomic_interrupted = get_pseudo_atomic_interrupted(thread);
482 int in_race_p = in_leaving_without_gcing_race_p(thread);
483 /* In the time window between leaving the *INTERRUPTS-ENABLED* NIL
484 * section and trapping, a SIG_STOP_FOR_GC would see the next
485 * check fail, for this reason sig_stop_for_gc handler does not
486 * call this function. */
487 if (interrupt_deferred_p) {
488 if (!(!interrupts_enabled || pseudo_atomic_interrupted || in_race_p))
489 lose("Stray deferred interrupt.\n");
492 if (!(pseudo_atomic_interrupted || gc_inhibit || in_race_p))
493 lose("GC_PENDING, but why?\n");
494 #if defined(LISP_FEATURE_SB_THREAD)
496 int stop_for_gc_pending =
497 (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL);
498 if (stop_for_gc_pending)
499 if (!(pseudo_atomic_interrupted || gc_inhibit || in_race_p))
500 lose("STOP_FOR_GC_PENDING, but why?\n");
504 if (interrupt_pending && !interrupt_deferred_p)
505 lose("INTERRUPT_PENDING but not pending handler.\n");
506 if ((data->gc_blocked_deferrables) && interrupt_pending)
507 lose("gc_blocked_deferrables and interrupt pending\n.");
508 if (data->gc_blocked_deferrables)
509 check_deferrables_blocked_or_lose(sigset);
510 if (interrupt_pending || interrupt_deferred_p ||
511 data->gc_blocked_deferrables)
512 check_deferrables_blocked_or_lose(sigset);
514 check_deferrables_unblocked_or_lose(sigset);
515 /* If deferrables are unblocked then we are open to signals
516 * that run lisp code. */
517 check_gc_signals_unblocked_or_lose(sigset);
522 /* When we catch an internal error, should we pass it back to Lisp to
523 * be handled in a high-level way? (Early in cold init, the answer is
524 * 'no', because Lisp is still too brain-dead to handle anything.
525 * After sufficient initialization has been completed, the answer
527 boolean internal_errors_enabled = 0;
529 #ifndef LISP_FEATURE_WIN32
531 void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, os_context_t*);
533 union interrupt_handler interrupt_handlers[NSIG];
537 * utility routines used by various signal handlers
541 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
543 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
547 /* Build a fake stack frame or frames */
549 current_control_frame_pointer =
550 (lispobj *)(unsigned long)
551 (*os_context_register_addr(context, reg_CSP));
552 if ((lispobj *)(unsigned long)
553 (*os_context_register_addr(context, reg_CFP))
554 == current_control_frame_pointer) {
555 /* There is a small window during call where the callee's
556 * frame isn't built yet. */
557 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
558 == FUN_POINTER_LOWTAG) {
559 /* We have called, but not built the new frame, so
560 * build it for them. */
561 current_control_frame_pointer[0] =
562 *os_context_register_addr(context, reg_OCFP);
563 current_control_frame_pointer[1] =
564 *os_context_register_addr(context, reg_LRA);
565 current_control_frame_pointer += 8;
566 /* Build our frame on top of it. */
567 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
570 /* We haven't yet called, build our frame as if the
571 * partial frame wasn't there. */
572 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
575 /* We can't tell whether we are still in the caller if it had to
576 * allocate a stack frame due to stack arguments. */
577 /* This observation provoked some past CMUCL maintainer to ask
578 * "Can anything strange happen during return?" */
581 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
584 current_control_stack_pointer = current_control_frame_pointer + 8;
586 current_control_frame_pointer[0] = oldcont;
587 current_control_frame_pointer[1] = NIL;
588 current_control_frame_pointer[2] =
589 (lispobj)(*os_context_register_addr(context, reg_CODE));
593 /* Stores the context for gc to scavange and builds fake stack
596 fake_foreign_function_call(os_context_t *context)
599 struct thread *thread=arch_os_get_current_thread();
601 /* context_index incrementing must not be interrupted */
602 check_blockables_blocked_or_lose(0);
604 /* Get current Lisp state from context. */
606 dynamic_space_free_pointer =
607 (lispobj *)(unsigned long)
608 (*os_context_register_addr(context, reg_ALLOC));
609 /* fprintf(stderr,"dynamic_space_free_pointer: %p\n", */
610 /* dynamic_space_free_pointer); */
611 #if defined(LISP_FEATURE_ALPHA) || defined(LISP_FEATURE_MIPS)
612 if ((long)dynamic_space_free_pointer & 1) {
613 lose("dead in fake_foreign_function_call, context = %x\n", context);
616 /* why doesnt PPC and SPARC do something like this: */
617 #if defined(LISP_FEATURE_HPPA)
618 if ((long)dynamic_space_free_pointer & 4) {
619 lose("dead in fake_foreign_function_call, context = %x, d_s_f_p = %x\n", context, dynamic_space_free_pointer);
624 current_binding_stack_pointer =
625 (lispobj *)(unsigned long)
626 (*os_context_register_addr(context, reg_BSP));
629 build_fake_control_stack_frames(thread,context);
631 /* Do dynamic binding of the active interrupt context index
632 * and save the context in the context array. */
634 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
636 if (context_index >= MAX_INTERRUPTS) {
637 lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS);
640 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
641 make_fixnum(context_index + 1),thread);
643 thread->interrupt_contexts[context_index] = context;
645 #ifdef FOREIGN_FUNCTION_CALL_FLAG
646 foreign_function_call_active = 1;
650 /* blocks all blockable signals. If you are calling from a signal handler,
651 * the usual signal mask will be restored from the context when the handler
652 * finishes. Otherwise, be careful */
654 undo_fake_foreign_function_call(os_context_t *context)
656 struct thread *thread=arch_os_get_current_thread();
657 /* Block all blockable signals. */
658 block_blockable_signals(0, 0);
660 #ifdef FOREIGN_FUNCTION_CALL_FLAG
661 foreign_function_call_active = 0;
664 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
668 /* Put the dynamic space free pointer back into the context. */
669 *os_context_register_addr(context, reg_ALLOC) =
670 (unsigned long) dynamic_space_free_pointer
671 | (*os_context_register_addr(context, reg_ALLOC)
674 ((unsigned long)(*os_context_register_addr(context, reg_ALLOC))
676 | ((unsigned long) dynamic_space_free_pointer & LOWTAG_MASK);
681 /* a handler for the signal caused by execution of a trap opcode
682 * signalling an internal error */
684 interrupt_internal_error(os_context_t *context, boolean continuable)
688 fake_foreign_function_call(context);
690 if (!internal_errors_enabled) {
691 describe_internal_error(context);
692 /* There's no good way to recover from an internal error
693 * before the Lisp error handling mechanism is set up. */
694 lose("internal error too early in init, can't recover\n");
697 /* Allocate the SAP object while the interrupts are still
699 unblock_gc_signals(0, 0);
700 context_sap = alloc_sap(context);
702 #ifndef LISP_FEATURE_WIN32
703 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
706 #if defined(LISP_FEATURE_LINUX) && defined(LISP_FEATURE_MIPS)
707 /* Workaround for blocked SIGTRAP. */
710 sigemptyset(&newset);
711 sigaddset(&newset, SIGTRAP);
712 thread_sigmask(SIG_UNBLOCK, &newset, 0);
716 SHOW("in interrupt_internal_error");
718 /* Display some rudimentary debugging information about the
719 * error, so that even if the Lisp error handler gets badly
720 * confused, we have a chance to determine what's going on. */
721 describe_internal_error(context);
723 funcall2(StaticSymbolFunction(INTERNAL_ERROR), context_sap,
724 continuable ? T : NIL);
726 undo_fake_foreign_function_call(context); /* blocks signals again */
728 arch_skip_instruction(context);
732 interrupt_handler_pending_p(void)
734 struct thread *thread = arch_os_get_current_thread();
735 struct interrupt_data *data = thread->interrupt_data;
736 return (data->pending_handler != 0);
740 interrupt_handle_pending(os_context_t *context)
742 /* There are three ways we can get here. First, if an interrupt
743 * occurs within pseudo-atomic, it will be deferred, and we'll
744 * trap to here at the end of the pseudo-atomic block. Second, if
745 * the GC (in alloc()) decides that a GC is required, it will set
746 * *GC-PENDING* and pseudo-atomic-interrupted if not *GC-INHIBIT*,
747 * and alloc() is always called from within pseudo-atomic, and
748 * thus we end up here again. Third, when calling GC-ON or at the
749 * end of a WITHOUT-GCING, MAYBE-HANDLE-PENDING-GC will trap to
750 * here if there is a pending GC. Fourth, ahem, at the end of
751 * WITHOUT-INTERRUPTS (bar complications with nesting). */
753 /* Win32 only needs to handle the GC cases (for now?) */
755 struct thread *thread = arch_os_get_current_thread();
756 struct interrupt_data *data = thread->interrupt_data;
758 if (arch_pseudo_atomic_atomic(context)) {
759 lose("Handling pending interrupt in pseduo atomic.");
762 FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n"));
764 check_blockables_blocked_or_lose(0);
766 /* If GC/SIG_STOP_FOR_GC struck during PA and there was no pending
767 * handler, then the pending mask was saved and
768 * gc_blocked_deferrables set. Hence, there can be no pending
769 * handler and it's safe to restore the pending mask.
771 * Note, that if gc_blocked_deferrables is false we may still have
772 * to GC. In this case, we are coming out of a WITHOUT-GCING or a
773 * pseudo atomic was interrupt be a deferrable first. */
774 if (data->gc_blocked_deferrables) {
775 if (data->pending_handler)
776 lose("GC blocked deferrables but still got a pending handler.");
777 if (SymbolValue(GC_INHIBIT,thread)!=NIL)
778 lose("GC blocked deferrables while GC is inhibited.");
779 /* Restore the saved signal mask from the original signal (the
780 * one that interrupted us during the critical section) into
781 * the os_context for the signal we're currently in the
782 * handler for. This should ensure that when we return from
783 * the handler the blocked signals are unblocked. */
784 #ifndef LISP_FEATURE_WIN32
785 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
787 data->gc_blocked_deferrables = 0;
790 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
791 void *original_pending_handler = data->pending_handler;
793 #ifdef LISP_FEATURE_SB_THREAD
794 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
795 /* STOP_FOR_GC_PENDING and GC_PENDING are cleared by
796 * the signal handler if it actually stops us. */
797 arch_clear_pseudo_atomic_interrupted(context);
798 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
801 /* Test for T and not for != NIL since the value :IN-PROGRESS
802 * is used in SUB-GC as part of the mechanism to supress
804 if (SymbolValue(GC_PENDING,thread) == T) {
806 /* Two reasons for doing this. First, if there is a
807 * pending handler we don't want to run. Second, we are
808 * going to clear pseudo atomic interrupted to avoid
809 * spurious trapping on every allocation in SUB_GC and
810 * having a pending handler with interrupts enabled and
811 * without pseudo atomic interrupted breaks an
813 if (data->pending_handler) {
814 bind_variable(ALLOW_WITH_INTERRUPTS, NIL, thread);
815 bind_variable(INTERRUPTS_ENABLED, NIL, thread);
818 arch_clear_pseudo_atomic_interrupted(context);
820 /* GC_PENDING is cleared in SUB-GC, or if another thread
821 * is doing a gc already we will get a SIG_STOP_FOR_GC and
822 * that will clear it.
824 * If there is a pending handler or gc was triggerred in a
825 * signal handler then maybe_gc won't run POST_GC and will
826 * return normally. */
827 if (!maybe_gc(context))
828 lose("GC not inhibited but maybe_gc did not GC.");
830 if (data->pending_handler) {
834 } else if (SymbolValue(GC_PENDING,thread) != NIL) {
835 /* It's not NIL or T so GC_PENDING is :IN-PROGRESS. If
836 * GC-PENDING is not NIL then we cannot trap on pseudo
837 * atomic due to GC (see if(GC_PENDING) logic in
838 * cheneygc.c an gengcgc.c), plus there is a outer
839 * WITHOUT-INTERRUPTS SUB_GC, so how did we end up
841 lose("Trapping to run pending handler while GC in progress.");
844 check_blockables_blocked_or_lose(0);
846 /* No GC shall be lost. If SUB_GC triggers another GC then
847 * that should be handled on the spot. */
848 if (SymbolValue(GC_PENDING,thread) != NIL)
849 lose("GC_PENDING after doing gc.");
850 #ifdef LISP_FEATURE_SB_THREAD
851 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL)
852 lose("STOP_FOR_GC_PENDING after doing gc.");
854 /* Check two things. First, that gc does not clobber a handler
855 * that's already pending. Second, that there is no interrupt
856 * lossage: if original_pending_handler was NULL then even if
857 * an interrupt arrived during GC (POST-GC, really) it was
859 if (original_pending_handler != data->pending_handler)
860 lose("pending handler changed in gc: %x -> %d.",
861 original_pending_handler, data->pending_handler);
864 #ifndef LISP_FEATURE_WIN32
865 /* There may be no pending handler, because it was only a gc that
866 * had to be executed or because Lisp is a bit too eager to call
867 * DO-PENDING-INTERRUPT. */
868 if ((SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) &&
869 (data->pending_handler)) {
870 /* No matter how we ended up here, clear both
871 * INTERRUPT_PENDING and pseudo atomic interrupted. It's safe
872 * because we checked above that there is no GC pending. */
873 SetSymbolValue(INTERRUPT_PENDING, NIL, thread);
874 arch_clear_pseudo_atomic_interrupted(context);
875 /* Restore the sigmask in the context. */
876 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
877 run_deferred_handler(data, context);
879 /* It is possible that the end of this function was reached
880 * without never actually doing anything, the tests in Lisp for
881 * when to call receive-pending-interrupt are not exact. */
882 FSHOW_SIGNAL((stderr, "/exiting interrupt_handle_pending\n"));
888 interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
890 #ifdef FOREIGN_FUNCTION_CALL_FLAG
891 boolean were_in_lisp;
893 union interrupt_handler handler;
895 check_blockables_blocked_or_lose(0);
897 #ifndef LISP_FEATURE_WIN32
898 if (sigismember(&deferrable_sigset,signal))
899 check_interrupts_enabled_or_lose(context);
902 handler = interrupt_handlers[signal];
904 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
908 #ifdef FOREIGN_FUNCTION_CALL_FLAG
909 were_in_lisp = !foreign_function_call_active;
913 fake_foreign_function_call(context);
916 FSHOW_SIGNAL((stderr,
917 "/entering interrupt_handle_now(%d, info, context)\n",
920 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
922 /* This can happen if someone tries to ignore or default one
923 * of the signals we need for runtime support, and the runtime
924 * support decides to pass on it. */
925 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
927 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
928 /* Once we've decided what to do about contexts in a
929 * return-elsewhere world (the original context will no longer
930 * be available; should we copy it or was nobody using it anyway?)
931 * then we should convert this to return-elsewhere */
933 /* CMUCL comment said "Allocate the SAPs while the interrupts
934 * are still disabled.". I (dan, 2003.08.21) assume this is
935 * because we're not in pseudoatomic and allocation shouldn't
936 * be interrupted. In which case it's no longer an issue as
937 * all our allocation from C now goes through a PA wrapper,
938 * but still, doesn't hurt.
940 * Yeah, but non-gencgc platforms don't really wrap allocation
941 * in PA. MG - 2005-08-29 */
943 lispobj info_sap, context_sap;
944 /* Leave deferrable signals blocked, the handler itself will
945 * allow signals again when it sees fit. */
946 unblock_gc_signals(0, 0);
947 context_sap = alloc_sap(context);
948 info_sap = alloc_sap(info);
950 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
952 funcall3(handler.lisp,
957 /* This cannot happen in sane circumstances. */
959 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
961 #ifndef LISP_FEATURE_WIN32
962 /* Allow signals again. */
963 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
965 (*handler.c)(signal, info, context);
968 #ifdef FOREIGN_FUNCTION_CALL_FLAG
972 undo_fake_foreign_function_call(context); /* block signals again */
975 FSHOW_SIGNAL((stderr,
976 "/returning from interrupt_handle_now(%d, info, context)\n",
980 /* This is called at the end of a critical section if the indications
981 * are that some signal was deferred during the section. Note that as
982 * far as C or the kernel is concerned we dealt with the signal
983 * already; we're just doing the Lisp-level processing now that we
986 run_deferred_handler(struct interrupt_data *data, os_context_t *context)
988 /* The pending_handler may enable interrupts and then another
989 * interrupt may hit, overwrite interrupt_data, so reset the
990 * pending handler before calling it. Trust the handler to finish
991 * with the siginfo before enabling interrupts. */
992 void (*pending_handler) (int, siginfo_t*, os_context_t*) =
993 data->pending_handler;
995 data->pending_handler=0;
996 FSHOW_SIGNAL((stderr, "/running deferred handler %p\n", pending_handler));
997 (*pending_handler)(data->pending_signal,&(data->pending_info), context);
1000 #ifndef LISP_FEATURE_WIN32
1002 maybe_defer_handler(void *handler, struct interrupt_data *data,
1003 int signal, siginfo_t *info, os_context_t *context)
1005 struct thread *thread=arch_os_get_current_thread();
1007 check_blockables_blocked_or_lose(0);
1009 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
1010 lose("interrupt already pending\n");
1011 if (thread->interrupt_data->pending_handler)
1012 lose("there is a pending handler already (PA)\n");
1013 if (data->gc_blocked_deferrables)
1014 lose("maybe_defer_handler: gc_blocked_deferrables true\n");
1015 check_interrupt_context_or_lose(context);
1016 /* If interrupts are disabled then INTERRUPT_PENDING is set and
1017 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
1018 * atomic section inside a WITHOUT-INTERRUPTS.
1020 * Also, if in_leaving_without_gcing_race_p then
1021 * interrupt_handle_pending is going to be called soon, so
1022 * stashing the signal away is safe.
1024 if ((SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) ||
1025 in_leaving_without_gcing_race_p(thread)) {
1026 store_signal_data_for_later(data,handler,signal,info,context);
1027 SetSymbolValue(INTERRUPT_PENDING, T,thread);
1028 FSHOW_SIGNAL((stderr,
1029 "/maybe_defer_handler(%x,%d): deferred (RACE=%d)\n",
1030 (unsigned int)handler,signal,
1031 in_leaving_without_gcing_race_p(thread)));
1032 check_interrupt_context_or_lose(context);
1035 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
1036 * actually use its argument for anything on x86, so this branch
1037 * may succeed even when context is null (gencgc alloc()) */
1038 if (arch_pseudo_atomic_atomic(context)) {
1039 store_signal_data_for_later(data,handler,signal,info,context);
1040 arch_set_pseudo_atomic_interrupted(context);
1041 FSHOW_SIGNAL((stderr,
1042 "/maybe_defer_handler(%x,%d): deferred(PA)\n",
1043 (unsigned int)handler,signal));
1044 check_interrupt_context_or_lose(context);
1047 FSHOW_SIGNAL((stderr,
1048 "/maybe_defer_handler(%x,%d): not deferred\n",
1049 (unsigned int)handler,signal));
1054 store_signal_data_for_later (struct interrupt_data *data, void *handler,
1056 siginfo_t *info, os_context_t *context)
1058 if (data->pending_handler)
1059 lose("tried to overwrite pending interrupt handler %x with %x\n",
1060 data->pending_handler, handler);
1062 lose("tried to defer null interrupt handler\n");
1063 data->pending_handler = handler;
1064 data->pending_signal = signal;
1066 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
1068 FSHOW_SIGNAL((stderr, "/store_signal_data_for_later: signal: %d\n",
1072 lose("Null context");
1074 /* the signal mask in the context (from before we were
1075 * interrupted) is copied to be restored when run_deferred_handler
1076 * happens. Then the usually-blocked signals are added to the mask
1077 * in the context so that we are running with blocked signals when
1078 * the handler returns */
1079 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
1080 sigaddset_deferrable(os_context_sigmask_addr(context));
1084 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
1086 SAVE_ERRNO(context,void_context);
1087 struct thread *thread = arch_os_get_current_thread();
1088 struct interrupt_data *data = thread->interrupt_data;
1090 if(!maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
1091 interrupt_handle_now(signal, info, context);
1096 low_level_interrupt_handle_now(int signal, siginfo_t *info,
1097 os_context_t *context)
1099 /* No FP control fixage needed, caller has done that. */
1100 check_blockables_blocked_or_lose(0);
1101 check_interrupts_enabled_or_lose(context);
1102 (*interrupt_low_level_handlers[signal])(signal, info, context);
1103 /* No Darwin context fixage needed, caller does that. */
1107 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
1109 SAVE_ERRNO(context,void_context);
1110 struct thread *thread = arch_os_get_current_thread();
1111 struct interrupt_data *data = thread->interrupt_data;
1113 if(!maybe_defer_handler(low_level_interrupt_handle_now,data,
1114 signal,info,context))
1115 low_level_interrupt_handle_now(signal, info, context);
1120 #ifdef LISP_FEATURE_SB_THREAD
1122 /* This function must not cons, because that may trigger a GC. */
1124 sig_stop_for_gc_handler(int signal, siginfo_t *info, os_context_t *context)
1126 struct thread *thread=arch_os_get_current_thread();
1128 /* Test for GC_INHIBIT _first_, else we'd trap on every single
1129 * pseudo atomic until gc is finally allowed. */
1130 if (SymbolValue(GC_INHIBIT,thread) != NIL) {
1131 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
1132 FSHOW_SIGNAL((stderr, "sig_stop_for_gc deferred (*GC-INHIBIT*)\n"));
1134 } else if (arch_pseudo_atomic_atomic(context)) {
1135 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
1136 arch_set_pseudo_atomic_interrupted(context);
1137 maybe_save_gc_mask_and_block_deferrables
1138 (os_context_sigmask_addr(context));
1139 FSHOW_SIGNAL((stderr,"sig_stop_for_gc deferred (PA)\n"));
1143 FSHOW_SIGNAL((stderr, "/sig_stop_for_gc_handler\n"));
1145 /* Not PA and GC not inhibited -- we can stop now. */
1147 /* need the context stored so it can have registers scavenged */
1148 fake_foreign_function_call(context);
1150 /* Not pending anymore. */
1151 SetSymbolValue(GC_PENDING,NIL,thread);
1152 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
1154 if(thread_state(thread)!=STATE_RUNNING) {
1155 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
1156 fixnum_value(thread->state));
1159 set_thread_state(thread,STATE_SUSPENDED);
1160 FSHOW_SIGNAL((stderr,"suspended\n"));
1162 wait_for_thread_state_change(thread, STATE_SUSPENDED);
1163 FSHOW_SIGNAL((stderr,"resumed\n"));
1165 if(thread_state(thread)!=STATE_RUNNING) {
1166 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
1167 fixnum_value(thread_state(thread)));
1170 undo_fake_foreign_function_call(context);
1176 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
1178 SAVE_ERRNO(context,void_context);
1179 #ifndef LISP_FEATURE_WIN32
1180 if ((signal == SIGILL) || (signal == SIGBUS)
1181 #ifndef LISP_FEATURE_LINUX
1182 || (signal == SIGEMT)
1185 corruption_warning_and_maybe_lose("Signal %d recieved", signal);
1187 interrupt_handle_now(signal, info, context);
1191 /* manipulate the signal context and stack such that when the handler
1192 * returns, it will call function instead of whatever it was doing
1196 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
1197 extern int *context_eflags_addr(os_context_t *context);
1200 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
1201 extern void post_signal_tramp(void);
1202 extern void call_into_lisp_tramp(void);
1204 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
1206 #ifndef LISP_FEATURE_WIN32
1207 check_gc_signals_unblocked_or_lose
1208 (os_context_sigmask_addr(context));
1210 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
1211 void * fun=native_pointer(function);
1212 void *code = &(((struct simple_fun *) fun)->code);
1215 /* Build a stack frame showing `interrupted' so that the
1216 * user's backtrace makes (as much) sense (as usual) */
1218 /* fp state is saved and restored by call_into_lisp */
1219 /* FIXME: errno is not restored, but since current uses of this
1220 * function only call Lisp code that signals an error, it's not
1221 * much of a problem. In other words, running out of the control
1222 * stack between a syscall and (GET-ERRNO) may clobber errno if
1223 * something fails during signalling or in the handler. But I
1224 * can't see what can go wrong as long as there is no CONTINUE
1225 * like restart on them. */
1226 #ifdef LISP_FEATURE_X86
1227 /* Suppose the existence of some function that saved all
1228 * registers, called call_into_lisp, then restored GP registers and
1229 * returned. It would look something like this:
1237 pushl {address of function to call}
1238 call 0x8058db0 <call_into_lisp>
1245 * What we do here is set up the stack that call_into_lisp would
1246 * expect to see if it had been called by this code, and frob the
1247 * signal context so that signal return goes directly to call_into_lisp,
1248 * and when that function (and the lisp function it invoked) returns,
1249 * it returns to the second half of this imaginary function which
1250 * restores all registers and returns to C
1252 * For this to work, the latter part of the imaginary function
1253 * must obviously exist in reality. That would be post_signal_tramp
1256 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
1258 #if defined(LISP_FEATURE_DARWIN)
1259 u32 *register_save_area = (u32 *)os_validate(0, 0x40);
1261 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp));
1262 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context));
1264 /* 1. os_validate (malloc/mmap) register_save_block
1265 * 2. copy register state into register_save_block
1266 * 3. put a pointer to register_save_block in a register in the context
1267 * 4. set the context's EIP to point to a trampoline which:
1268 * a. builds the fake stack frame from the block
1269 * b. frees the block
1270 * c. calls the function
1273 *register_save_area = *os_context_pc_addr(context);
1274 *(register_save_area + 1) = function;
1275 *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI);
1276 *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI);
1277 *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX);
1278 *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX);
1279 *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX);
1280 *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX);
1281 *(register_save_area + 8) = *context_eflags_addr(context);
1283 *os_context_pc_addr(context) =
1284 (os_context_register_t) call_into_lisp_tramp;
1285 *os_context_register_addr(context,reg_ECX) =
1286 (os_context_register_t) register_save_area;
1289 /* return address for call_into_lisp: */
1290 *(sp-15) = (u32)post_signal_tramp;
1291 *(sp-14) = function; /* args for call_into_lisp : function*/
1292 *(sp-13) = 0; /* arg array */
1293 *(sp-12) = 0; /* no. args */
1294 /* this order matches that used in POPAD */
1295 *(sp-11)=*os_context_register_addr(context,reg_EDI);
1296 *(sp-10)=*os_context_register_addr(context,reg_ESI);
1298 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
1299 /* POPAD ignores the value of ESP: */
1301 *(sp-7)=*os_context_register_addr(context,reg_EBX);
1303 *(sp-6)=*os_context_register_addr(context,reg_EDX);
1304 *(sp-5)=*os_context_register_addr(context,reg_ECX);
1305 *(sp-4)=*os_context_register_addr(context,reg_EAX);
1306 *(sp-3)=*context_eflags_addr(context);
1307 *(sp-2)=*os_context_register_addr(context,reg_EBP);
1308 *(sp-1)=*os_context_pc_addr(context);
1312 #elif defined(LISP_FEATURE_X86_64)
1313 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
1315 /* return address for call_into_lisp: */
1316 *(sp-18) = (u64)post_signal_tramp;
1318 *(sp-17)=*os_context_register_addr(context,reg_R15);
1319 *(sp-16)=*os_context_register_addr(context,reg_R14);
1320 *(sp-15)=*os_context_register_addr(context,reg_R13);
1321 *(sp-14)=*os_context_register_addr(context,reg_R12);
1322 *(sp-13)=*os_context_register_addr(context,reg_R11);
1323 *(sp-12)=*os_context_register_addr(context,reg_R10);
1324 *(sp-11)=*os_context_register_addr(context,reg_R9);
1325 *(sp-10)=*os_context_register_addr(context,reg_R8);
1326 *(sp-9)=*os_context_register_addr(context,reg_RDI);
1327 *(sp-8)=*os_context_register_addr(context,reg_RSI);
1328 /* skip RBP and RSP */
1329 *(sp-7)=*os_context_register_addr(context,reg_RBX);
1330 *(sp-6)=*os_context_register_addr(context,reg_RDX);
1331 *(sp-5)=*os_context_register_addr(context,reg_RCX);
1332 *(sp-4)=*os_context_register_addr(context,reg_RAX);
1333 *(sp-3)=*context_eflags_addr(context);
1334 *(sp-2)=*os_context_register_addr(context,reg_RBP);
1335 *(sp-1)=*os_context_pc_addr(context);
1337 *os_context_register_addr(context,reg_RDI) =
1338 (os_context_register_t)function; /* function */
1339 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
1340 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
1342 struct thread *th=arch_os_get_current_thread();
1343 build_fake_control_stack_frames(th,context);
1346 #ifdef LISP_FEATURE_X86
1348 #if !defined(LISP_FEATURE_DARWIN)
1349 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
1350 *os_context_register_addr(context,reg_ECX) = 0;
1351 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
1353 *os_context_register_addr(context,reg_UESP) =
1354 (os_context_register_t)(sp-15);
1356 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
1357 #endif /* __NETBSD__ */
1358 #endif /* LISP_FEATURE_DARWIN */
1360 #elif defined(LISP_FEATURE_X86_64)
1361 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
1362 *os_context_register_addr(context,reg_RCX) = 0;
1363 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
1364 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
1366 /* this much of the calling convention is common to all
1368 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
1369 *os_context_register_addr(context,reg_NARGS) = 0;
1370 *os_context_register_addr(context,reg_LIP) =
1371 (os_context_register_t)(unsigned long)code;
1372 *os_context_register_addr(context,reg_CFP) =
1373 (os_context_register_t)(unsigned long)current_control_frame_pointer;
1375 #ifdef ARCH_HAS_NPC_REGISTER
1376 *os_context_npc_addr(context) =
1377 4 + *os_context_pc_addr(context);
1379 #ifdef LISP_FEATURE_SPARC
1380 *os_context_register_addr(context,reg_CODE) =
1381 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
1383 FSHOW((stderr, "/arranged return to Lisp function (0x%lx)\n",
1387 /* KLUDGE: Theoretically the approach we use for undefined alien
1388 * variables should work for functions as well, but on PPC/Darwin
1389 * we get bus error at bogus addresses instead, hence this workaround,
1390 * that has the added benefit of automatically discriminating between
1391 * functions and variables.
1394 undefined_alien_function(void)
1396 funcall0(StaticSymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
1400 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
1402 struct thread *th=arch_os_get_current_thread();
1404 /* note the os_context hackery here. When the signal handler returns,
1405 * it won't go back to what it was doing ... */
1406 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
1407 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1408 /* We hit the end of the control stack: disable guard page
1409 * protection so the error handler has some headroom, protect the
1410 * previous page so that we can catch returns from the guard page
1411 * and restore it. */
1412 corruption_warning_and_maybe_lose("Control stack exhausted");
1413 protect_control_stack_guard_page(0, NULL);
1414 protect_control_stack_return_guard_page(1, NULL);
1416 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1417 /* For the unfortunate case, when the control stack is
1418 * exhausted in a signal handler. */
1419 unblock_signals_in_context_and_maybe_warn(context);
1421 arrange_return_to_lisp_function
1422 (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
1425 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
1426 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1427 /* We're returning from the guard page: reprotect it, and
1428 * unprotect this one. This works even if we somehow missed
1429 * the return-guard-page, and hit it on our way to new
1430 * exhaustion instead. */
1431 fprintf(stderr, "INFO: Control stack guard page reprotected\n");
1432 protect_control_stack_guard_page(1, NULL);
1433 protect_control_stack_return_guard_page(0, NULL);
1436 else if(addr >= BINDING_STACK_GUARD_PAGE(th) &&
1437 addr < BINDING_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1438 corruption_warning_and_maybe_lose("Binding stack exhausted");
1439 protect_binding_stack_guard_page(0, NULL);
1440 protect_binding_stack_return_guard_page(1, NULL);
1442 /* For the unfortunate case, when the binding stack is
1443 * exhausted in a signal handler. */
1444 unblock_signals_in_context_and_maybe_warn(context);
1445 arrange_return_to_lisp_function
1446 (context, StaticSymbolFunction(BINDING_STACK_EXHAUSTED_ERROR));
1449 else if(addr >= BINDING_STACK_RETURN_GUARD_PAGE(th) &&
1450 addr < BINDING_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1451 fprintf(stderr, "INFO: Binding stack guard page reprotected\n");
1452 protect_binding_stack_guard_page(1, NULL);
1453 protect_binding_stack_return_guard_page(0, NULL);
1456 else if(addr >= ALIEN_STACK_GUARD_PAGE(th) &&
1457 addr < ALIEN_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1458 corruption_warning_and_maybe_lose("Alien stack exhausted");
1459 protect_alien_stack_guard_page(0, NULL);
1460 protect_alien_stack_return_guard_page(1, NULL);
1462 /* For the unfortunate case, when the alien stack is
1463 * exhausted in a signal handler. */
1464 unblock_signals_in_context_and_maybe_warn(context);
1465 arrange_return_to_lisp_function
1466 (context, StaticSymbolFunction(ALIEN_STACK_EXHAUSTED_ERROR));
1469 else if(addr >= ALIEN_STACK_RETURN_GUARD_PAGE(th) &&
1470 addr < ALIEN_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1471 fprintf(stderr, "INFO: Alien stack guard page reprotected\n");
1472 protect_alien_stack_guard_page(1, NULL);
1473 protect_alien_stack_return_guard_page(0, NULL);
1476 else if (addr >= undefined_alien_address &&
1477 addr < undefined_alien_address + os_vm_page_size) {
1478 arrange_return_to_lisp_function
1479 (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
1486 * noise to install handlers
1489 #ifndef LISP_FEATURE_WIN32
1490 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1491 * they are blocked, in Linux 2.6 the default handler is invoked
1492 * instead that usually coredumps. One might hastily think that adding
1493 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1494 * the whole sa_mask is ignored and instead of not adding the signal
1495 * in question to the mask. That means if it's not blockable the
1496 * signal must be unblocked at the beginning of signal handlers.
1498 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1499 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1500 * will be unblocked in the sigmask during the signal handler. -- RMK
1503 static volatile int sigaction_nodefer_works = -1;
1505 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1506 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1509 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1513 get_current_sigmask(¤t);
1514 /* There should be exactly two blocked signals: the two we added
1515 * to sa_mask when setting up the handler. NetBSD doesn't block
1516 * the signal we're handling when SA_NODEFER is set; Linux before
1517 * 2.6.13 or so also doesn't block the other signal when
1518 * SA_NODEFER is set. */
1519 for(i = 1; i < NSIG; i++)
1520 if (sigismember(¤t, i) !=
1521 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1522 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1523 sigaction_nodefer_works = 0;
1525 if (sigaction_nodefer_works == -1)
1526 sigaction_nodefer_works = 1;
1530 see_if_sigaction_nodefer_works(void)
1532 struct sigaction sa, old_sa;
1534 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1535 sa.sa_sigaction = sigaction_nodefer_test_handler;
1536 sigemptyset(&sa.sa_mask);
1537 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1538 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1539 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1540 /* Make sure no signals are blocked. */
1543 sigemptyset(&empty);
1544 thread_sigmask(SIG_SETMASK, &empty, 0);
1546 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1547 while (sigaction_nodefer_works == -1);
1548 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1551 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1552 #undef SA_NODEFER_TEST_KILL_SIGNAL
1555 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1557 SAVE_ERRNO(context,void_context);
1560 sigemptyset(&unblock);
1561 sigaddset(&unblock, signal);
1562 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1563 interrupt_handle_now(signal, info, context);
1568 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1570 SAVE_ERRNO(context,void_context);
1573 sigemptyset(&unblock);
1574 sigaddset(&unblock, signal);
1575 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1576 (*interrupt_low_level_handlers[signal])(signal, info, context);
1581 low_level_handle_now_handler(int signal, siginfo_t *info, void *void_context)
1583 SAVE_ERRNO(context,void_context);
1584 (*interrupt_low_level_handlers[signal])(signal, info, context);
1589 undoably_install_low_level_interrupt_handler (int signal,
1590 interrupt_handler_t handler)
1592 struct sigaction sa;
1594 if (0 > signal || signal >= NSIG) {
1595 lose("bad signal number %d\n", signal);
1598 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1599 sa.sa_sigaction = (void (*)(int, siginfo_t*, void*))handler;
1600 else if (sigismember(&deferrable_sigset,signal))
1601 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1602 else if (!sigaction_nodefer_works &&
1603 !sigismember(&blockable_sigset, signal))
1604 sa.sa_sigaction = low_level_unblock_me_trampoline;
1606 sa.sa_sigaction = low_level_handle_now_handler;
1608 sigcopyset(&sa.sa_mask, &blockable_sigset);
1609 sa.sa_flags = SA_SIGINFO | SA_RESTART
1610 | (sigaction_nodefer_works ? SA_NODEFER : 0);
1611 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1612 if((signal==SIG_MEMORY_FAULT))
1613 sa.sa_flags |= SA_ONSTACK;
1616 sigaction(signal, &sa, NULL);
1617 interrupt_low_level_handlers[signal] =
1618 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1622 /* This is called from Lisp. */
1624 install_handler(int signal, void handler(int, siginfo_t*, os_context_t*))
1626 #ifndef LISP_FEATURE_WIN32
1627 struct sigaction sa;
1629 union interrupt_handler oldhandler;
1631 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1633 block_blockable_signals(0, &old);
1635 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1636 (unsigned int)interrupt_low_level_handlers[signal]));
1637 if (interrupt_low_level_handlers[signal]==0) {
1638 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1639 ARE_SAME_HANDLER(handler, SIG_IGN))
1640 sa.sa_sigaction = (void (*)(int, siginfo_t*, void*))handler;
1641 else if (sigismember(&deferrable_sigset, signal))
1642 sa.sa_sigaction = maybe_now_maybe_later;
1643 else if (!sigaction_nodefer_works &&
1644 !sigismember(&blockable_sigset, signal))
1645 sa.sa_sigaction = unblock_me_trampoline;
1647 sa.sa_sigaction = interrupt_handle_now_handler;
1649 sigcopyset(&sa.sa_mask, &blockable_sigset);
1650 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1651 (sigaction_nodefer_works ? SA_NODEFER : 0);
1652 sigaction(signal, &sa, NULL);
1655 oldhandler = interrupt_handlers[signal];
1656 interrupt_handlers[signal].c = handler;
1658 thread_sigmask(SIG_SETMASK, &old, 0);
1660 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1662 return (unsigned long)oldhandler.lisp;
1664 /* Probably-wrong Win32 hack */
1669 /* This must not go through lisp as it's allowed anytime, even when on
1672 sigabrt_handler(int signal, siginfo_t *info, os_context_t *context)
1674 lose("SIGABRT received.\n");
1678 interrupt_init(void)
1680 #ifndef LISP_FEATURE_WIN32
1682 SHOW("entering interrupt_init()");
1683 see_if_sigaction_nodefer_works();
1684 sigemptyset(&deferrable_sigset);
1685 sigemptyset(&blockable_sigset);
1686 sigemptyset(&gc_sigset);
1687 sigaddset_deferrable(&deferrable_sigset);
1688 sigaddset_blockable(&blockable_sigset);
1689 sigaddset_gc(&gc_sigset);
1691 /* Set up high level handler information. */
1692 for (i = 0; i < NSIG; i++) {
1693 interrupt_handlers[i].c =
1694 /* (The cast here blasts away the distinction between
1695 * SA_SIGACTION-style three-argument handlers and
1696 * signal(..)-style one-argument handlers, which is OK
1697 * because it works to call the 1-argument form where the
1698 * 3-argument form is expected.) */
1699 (void (*)(int, siginfo_t*, os_context_t*))SIG_DFL;
1701 undoably_install_low_level_interrupt_handler(SIGABRT, sigabrt_handler);
1702 SHOW("returning from interrupt_init()");
1706 #ifndef LISP_FEATURE_WIN32
1708 siginfo_code(siginfo_t *info)
1710 return info->si_code;
1712 os_vm_address_t current_memory_fault_address;
1715 lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr)
1717 /* FIXME: This is lossy: if we get another memory fault (eg. from
1718 * another thread) before lisp has read this, we lose the information.
1719 * However, since this is mostly informative, we'll live with that for
1720 * now -- some address is better then no address in this case.
1722 current_memory_fault_address = addr;
1723 /* To allow debugging memory faults in signal handlers and such. */
1724 corruption_warning_and_maybe_lose("Memory fault at %x (pc=%p, sp=%p)",
1726 *os_context_pc_addr(context),
1727 #ifdef ARCH_HAS_STACK_POINTER
1728 *os_context_sp_addr(context)
1733 unblock_signals_in_context_and_maybe_warn(context);
1734 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1735 arrange_return_to_lisp_function(context,
1736 StaticSymbolFunction(MEMORY_FAULT_ERROR));
1738 funcall0(StaticSymbolFunction(MEMORY_FAULT_ERROR));
1744 unhandled_trap_error(os_context_t *context)
1746 lispobj context_sap;
1747 fake_foreign_function_call(context);
1748 unblock_gc_signals(0, 0);
1749 context_sap = alloc_sap(context);
1750 #ifndef LISP_FEATURE_WIN32
1751 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1753 funcall1(StaticSymbolFunction(UNHANDLED_TRAP_ERROR), context_sap);
1754 lose("UNHANDLED-TRAP-ERROR fell through");
1757 /* Common logic for trapping instructions. How we actually handle each
1758 * case is highly architecture dependent, but the overall shape is
1761 handle_trap(os_context_t *context, int trap)
1764 case trap_PendingInterrupt:
1765 FSHOW((stderr, "/<trap pending interrupt>\n"));
1766 arch_skip_instruction(context);
1767 interrupt_handle_pending(context);
1771 FSHOW((stderr, "/<trap error/cerror %d>\n", trap));
1772 interrupt_internal_error(context, trap==trap_Cerror);
1774 case trap_Breakpoint:
1775 arch_handle_breakpoint(context);
1777 case trap_FunEndBreakpoint:
1778 arch_handle_fun_end_breakpoint(context);
1780 #ifdef trap_AfterBreakpoint
1781 case trap_AfterBreakpoint:
1782 arch_handle_after_breakpoint(context);
1785 #ifdef trap_SingleStepAround
1786 case trap_SingleStepAround:
1787 case trap_SingleStepBefore:
1788 arch_handle_single_step_trap(context, trap);
1792 fake_foreign_function_call(context);
1793 lose("%%PRIMITIVE HALT called; the party is over.\n");
1795 unhandled_trap_error(context);