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 #ifndef LISP_FEATURE_HPUX
90 sigaddset(s, SIGXCPU);
91 sigaddset(s, SIGXFSZ);
93 sigaddset(s, SIGVTALRM);
94 sigaddset(s, SIGPROF);
95 sigaddset(s, SIGWINCH);
97 #if !((defined(LISP_FEATURE_DARWIN) || defined(LISP_FEATURE_FREEBSD)) && defined(LISP_FEATURE_SB_THREAD))
98 sigaddset(s, SIGUSR1);
99 sigaddset(s, SIGUSR2);
102 #ifdef LISP_FEATURE_SB_THREAD
103 sigaddset(s, SIG_INTERRUPT_THREAD);
108 sigaddset_blockable(sigset_t *s)
110 sigaddset_deferrable(s);
111 #ifdef LISP_FEATURE_SB_THREAD
112 #ifdef SIG_RESUME_FROM_GC
113 sigaddset(s, SIG_RESUME_FROM_GC);
115 sigaddset(s, SIG_STOP_FOR_GC);
119 /* initialized in interrupt_init */
120 sigset_t deferrable_sigset;
121 sigset_t blockable_sigset;
125 check_blockables_blocked_or_lose(void)
127 #if !defined(LISP_FEATURE_WIN32)
128 /* Get the current sigmask, by blocking the empty set. */
129 sigset_t empty,current;
132 thread_sigmask(SIG_BLOCK, &empty, ¤t);
133 for(i = 1; i < NSIG; i++) {
134 if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i))
135 lose("blockable signal %d not blocked\n",i);
141 unblock_gc_signals(void)
143 #ifdef LISP_FEATURE_SB_THREAD
146 #if defined(SIG_RESUME_FROM_GC)
147 sigaddset(&new,SIG_RESUME_FROM_GC);
149 sigaddset(&new,SIG_STOP_FOR_GC);
150 thread_sigmask(SIG_UNBLOCK,&new,0);
155 check_interrupts_enabled_or_lose(os_context_t *context)
157 struct thread *thread=arch_os_get_current_thread();
158 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
159 lose("interrupts not enabled\n");
160 if (arch_pseudo_atomic_atomic(context))
161 lose ("in pseudo atomic section\n");
164 /* When we catch an internal error, should we pass it back to Lisp to
165 * be handled in a high-level way? (Early in cold init, the answer is
166 * 'no', because Lisp is still too brain-dead to handle anything.
167 * After sufficient initialization has been completed, the answer
169 boolean internal_errors_enabled = 0;
171 #ifndef LISP_FEATURE_WIN32
172 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*);
174 union interrupt_handler interrupt_handlers[NSIG];
176 /* At the toplevel repl we routinely call this function. The signal
177 * mask ought to be clear anyway most of the time, but may be non-zero
178 * if we were interrupted e.g. while waiting for a queue. */
181 reset_signal_mask(void)
183 #ifndef LISP_FEATURE_WIN32
186 thread_sigmask(SIG_SETMASK,&new,0);
191 block_blockable_signals(void)
193 #ifndef LISP_FEATURE_WIN32
194 thread_sigmask(SIG_BLOCK, &blockable_sigset, 0);
199 block_deferrable_signals(void)
201 #ifndef LISP_FEATURE_WIN32
202 thread_sigmask(SIG_BLOCK, &deferrable_sigset, 0);
208 * utility routines used by various signal handlers
212 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
214 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
218 /* Build a fake stack frame or frames */
220 current_control_frame_pointer =
221 (lispobj *)(unsigned long)
222 (*os_context_register_addr(context, reg_CSP));
223 if ((lispobj *)(unsigned long)
224 (*os_context_register_addr(context, reg_CFP))
225 == current_control_frame_pointer) {
226 /* There is a small window during call where the callee's
227 * frame isn't built yet. */
228 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
229 == FUN_POINTER_LOWTAG) {
230 /* We have called, but not built the new frame, so
231 * build it for them. */
232 current_control_frame_pointer[0] =
233 *os_context_register_addr(context, reg_OCFP);
234 current_control_frame_pointer[1] =
235 *os_context_register_addr(context, reg_LRA);
236 current_control_frame_pointer += 8;
237 /* Build our frame on top of it. */
238 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
241 /* We haven't yet called, build our frame as if the
242 * partial frame wasn't there. */
243 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
246 /* We can't tell whether we are still in the caller if it had to
247 * allocate a stack frame due to stack arguments. */
248 /* This observation provoked some past CMUCL maintainer to ask
249 * "Can anything strange happen during return?" */
252 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
255 current_control_stack_pointer = current_control_frame_pointer + 8;
257 current_control_frame_pointer[0] = oldcont;
258 current_control_frame_pointer[1] = NIL;
259 current_control_frame_pointer[2] =
260 (lispobj)(*os_context_register_addr(context, reg_CODE));
264 /* Stores the context for gc to scavange and builds fake stack
267 fake_foreign_function_call(os_context_t *context)
270 struct thread *thread=arch_os_get_current_thread();
272 /* context_index incrementing must not be interrupted */
273 check_blockables_blocked_or_lose();
275 /* Get current Lisp state from context. */
277 dynamic_space_free_pointer =
278 (lispobj *)(unsigned long)
279 (*os_context_register_addr(context, reg_ALLOC));
280 /* fprintf(stderr,"dynamic_space_free_pointer: %p\n", */
281 /* dynamic_space_free_pointer); */
282 #if defined(LISP_FEATURE_ALPHA) || defined(LISP_FEATURE_MIPS)
283 if ((long)dynamic_space_free_pointer & 1) {
284 lose("dead in fake_foreign_function_call, context = %x\n", context);
287 /* why doesnt PPC and SPARC do something like this: */
288 #if defined(LISP_FEATURE_HPPA)
289 if ((long)dynamic_space_free_pointer & 4) {
290 lose("dead in fake_foreign_function_call, context = %x, d_s_f_p = %x\n", context, dynamic_space_free_pointer);
295 current_binding_stack_pointer =
296 (lispobj *)(unsigned long)
297 (*os_context_register_addr(context, reg_BSP));
300 build_fake_control_stack_frames(thread,context);
302 /* Do dynamic binding of the active interrupt context index
303 * and save the context in the context array. */
305 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
307 if (context_index >= MAX_INTERRUPTS) {
308 lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS);
311 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
312 make_fixnum(context_index + 1),thread);
314 thread->interrupt_contexts[context_index] = context;
316 #ifdef FOREIGN_FUNCTION_CALL_FLAG
317 foreign_function_call_active = 1;
321 /* blocks all blockable signals. If you are calling from a signal handler,
322 * the usual signal mask will be restored from the context when the handler
323 * finishes. Otherwise, be careful */
325 undo_fake_foreign_function_call(os_context_t *context)
327 struct thread *thread=arch_os_get_current_thread();
328 /* Block all blockable signals. */
329 block_blockable_signals();
331 #ifdef FOREIGN_FUNCTION_CALL_FLAG
332 foreign_function_call_active = 0;
335 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
339 /* Put the dynamic space free pointer back into the context. */
340 *os_context_register_addr(context, reg_ALLOC) =
341 (unsigned long) dynamic_space_free_pointer
342 | (*os_context_register_addr(context, reg_ALLOC)
345 ((unsigned long)(*os_context_register_addr(context, reg_ALLOC))
347 | ((unsigned long) dynamic_space_free_pointer & LOWTAG_MASK);
352 /* a handler for the signal caused by execution of a trap opcode
353 * signalling an internal error */
355 interrupt_internal_error(os_context_t *context, boolean continuable)
359 fake_foreign_function_call(context);
361 if (!internal_errors_enabled) {
362 describe_internal_error(context);
363 /* There's no good way to recover from an internal error
364 * before the Lisp error handling mechanism is set up. */
365 lose("internal error too early in init, can't recover\n");
368 /* Allocate the SAP object while the interrupts are still
370 context_sap = alloc_sap(context);
372 #ifndef LISP_FEATURE_WIN32
373 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
376 SHOW("in interrupt_internal_error");
378 /* Display some rudimentary debugging information about the
379 * error, so that even if the Lisp error handler gets badly
380 * confused, we have a chance to determine what's going on. */
381 describe_internal_error(context);
383 funcall2(StaticSymbolFunction(INTERNAL_ERROR), context_sap,
384 continuable ? T : NIL);
386 undo_fake_foreign_function_call(context); /* blocks signals again */
388 arch_skip_instruction(context);
392 interrupt_handle_pending(os_context_t *context)
394 /* There are three ways we can get here. First, if an interrupt
395 * occurs within pseudo-atomic, it will be deferred, and we'll
396 * trap to here at the end of the pseudo-atomic block. Second, if
397 * the GC (in alloc()) decides that a GC is required, it will set
398 * *GC-PENDING* and pseudo-atomic-interrupted if not *GC-INHIBIT*,
399 * and alloc() is always called from within pseudo-atomic, and
400 * thus we end up here again. Third, when calling GC-ON or at the
401 * end of a WITHOUT-GCING, MAYBE-HANDLE-PENDING-GC will trap to
402 * here if there is a pending GC. Fourth, ahem, at the end of
403 * WITHOUT-INTERRUPTS (bar complications with nesting). */
405 /* Win32 only needs to handle the GC cases (for now?) */
407 struct thread *thread;
409 /* Punt if in PA section, marking it as interrupted. This can
410 * happenat least if we pick up a GC request while in a
411 * WITHOUT-GCING with an outer PA -- it is not immediately clear
412 * to me that this should/could ever happen, but better safe then
413 * sorry. --NS 2007-05-15 */
414 if (arch_pseudo_atomic_atomic(context)) {
415 arch_set_pseudo_atomic_interrupted(context);
419 thread = arch_os_get_current_thread();
421 FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n"));
423 check_blockables_blocked_or_lose();
425 /* If pseudo_atomic_interrupted is set then the interrupt is going
426 * to be handled now, ergo it's safe to clear it. */
427 arch_clear_pseudo_atomic_interrupted(context);
429 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
430 #ifdef LISP_FEATURE_SB_THREAD
431 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
432 /* STOP_FOR_GC_PENDING and GC_PENDING are cleared by
433 * the signal handler if it actually stops us. */
434 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
437 if (SymbolValue(GC_PENDING,thread) != NIL) {
438 /* GC_PENDING is cleared in SUB-GC, or if another thread
439 * is doing a gc already we will get a SIG_STOP_FOR_GC and
440 * that will clear it. */
443 check_blockables_blocked_or_lose();
446 #ifndef LISP_FEATURE_WIN32
447 /* we may be here only to do the gc stuff, if interrupts are
448 * enabled run the pending handler */
449 if (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) {
450 struct interrupt_data *data = thread->interrupt_data;
452 /* There may be no pending handler, because it was only a gc
453 * that had to be executed or because pseudo atomic triggered
454 * twice for a single interrupt. For the interested reader,
455 * that may happen if an interrupt hits after the interrupted
456 * flag is cleared but before pseudo-atomic is set and a
457 * pseudo atomic is interrupted in that interrupt. */
458 if (data->pending_handler) {
460 /* If we're here as the result of a pseudo-atomic as opposed
461 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
462 * NIL, because maybe_defer_handler sets
463 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
464 SetSymbolValue(INTERRUPT_PENDING, NIL, thread);
466 /* restore the saved signal mask from the original signal (the
467 * one that interrupted us during the critical section) into the
468 * os_context for the signal we're currently in the handler for.
469 * This should ensure that when we return from the handler the
470 * blocked signals are unblocked */
471 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
473 sigemptyset(&data->pending_mask);
474 /* This will break on sparc linux: the deferred handler really wants
475 * to be called with a void_context */
476 run_deferred_handler(data,(void *)context);
483 * the two main signal handlers:
484 * interrupt_handle_now(..)
485 * maybe_now_maybe_later(..)
487 * to which we have added interrupt_handle_now_handler(..). Why?
488 * Well, mostly because the SPARC/Linux platform doesn't quite do
489 * signals the way we want them done. The third argument in the
490 * handler isn't filled in by the kernel properly, so we fix it up
491 * ourselves in the arch_os_get_context(..) function; however, we only
492 * want to do this when we first hit the handler, and not when
493 * interrupt_handle_now(..) is being called from some other handler
494 * (when the fixup will already have been done). -- CSR, 2002-07-23
498 interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
500 #ifdef FOREIGN_FUNCTION_CALL_FLAG
501 boolean were_in_lisp;
503 union interrupt_handler handler;
505 check_blockables_blocked_or_lose();
507 #ifndef LISP_FEATURE_WIN32
508 if (sigismember(&deferrable_sigset,signal))
509 check_interrupts_enabled_or_lose(context);
512 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
513 /* Under Linux on some architectures, we appear to have to restore
514 the FPU control word from the context, as after the signal is
515 delivered we appear to have a null FPU control word. */
516 os_restore_fp_control(context);
519 handler = interrupt_handlers[signal];
521 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
525 #ifdef FOREIGN_FUNCTION_CALL_FLAG
526 were_in_lisp = !foreign_function_call_active;
530 fake_foreign_function_call(context);
533 FSHOW_SIGNAL((stderr,
534 "/entering interrupt_handle_now(%d, info, context)\n",
537 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
539 /* This can happen if someone tries to ignore or default one
540 * of the signals we need for runtime support, and the runtime
541 * support decides to pass on it. */
542 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
544 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
545 /* Once we've decided what to do about contexts in a
546 * return-elsewhere world (the original context will no longer
547 * be available; should we copy it or was nobody using it anyway?)
548 * then we should convert this to return-elsewhere */
550 /* CMUCL comment said "Allocate the SAPs while the interrupts
551 * are still disabled.". I (dan, 2003.08.21) assume this is
552 * because we're not in pseudoatomic and allocation shouldn't
553 * be interrupted. In which case it's no longer an issue as
554 * all our allocation from C now goes through a PA wrapper,
555 * but still, doesn't hurt.
557 * Yeah, but non-gencgc platforms don't really wrap allocation
558 * in PA. MG - 2005-08-29 */
560 lispobj info_sap,context_sap = alloc_sap(context);
561 info_sap = alloc_sap(info);
562 /* Leave deferrable signals blocked, the handler itself will
563 * allow signals again when it sees fit. */
564 #ifdef LISP_FEATURE_SB_THREAD
567 sigemptyset(&unblock);
568 sigaddset(&unblock, SIG_STOP_FOR_GC);
569 #ifdef SIG_RESUME_FROM_GC
570 sigaddset(&unblock, SIG_RESUME_FROM_GC);
572 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
576 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
578 funcall3(handler.lisp,
584 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
586 #ifndef LISP_FEATURE_WIN32
587 /* Allow signals again. */
588 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
590 (*handler.c)(signal, info, context);
593 #ifdef FOREIGN_FUNCTION_CALL_FLAG
597 undo_fake_foreign_function_call(context); /* block signals again */
600 FSHOW_SIGNAL((stderr,
601 "/returning from interrupt_handle_now(%d, info, context)\n",
605 /* This is called at the end of a critical section if the indications
606 * are that some signal was deferred during the section. Note that as
607 * far as C or the kernel is concerned we dealt with the signal
608 * already; we're just doing the Lisp-level processing now that we
611 run_deferred_handler(struct interrupt_data *data, void *v_context)
613 /* The pending_handler may enable interrupts and then another
614 * interrupt may hit, overwrite interrupt_data, so reset the
615 * pending handler before calling it. Trust the handler to finish
616 * with the siginfo before enabling interrupts. */
617 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
619 data->pending_handler=0;
620 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
623 #ifndef LISP_FEATURE_WIN32
625 maybe_defer_handler(void *handler, struct interrupt_data *data,
626 int signal, siginfo_t *info, os_context_t *context)
628 struct thread *thread=arch_os_get_current_thread();
630 check_blockables_blocked_or_lose();
632 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
633 lose("interrupt already pending\n");
634 /* If interrupts are disabled then INTERRUPT_PENDING is set and
635 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
636 * atomic section inside a WITHOUT-INTERRUPTS.
638 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
639 store_signal_data_for_later(data,handler,signal,info,context);
640 SetSymbolValue(INTERRUPT_PENDING, T,thread);
641 FSHOW_SIGNAL((stderr,
642 "/maybe_defer_handler(%x,%d): deferred\n",
643 (unsigned int)handler,signal));
646 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
647 * actually use its argument for anything on x86, so this branch
648 * may succeed even when context is null (gencgc alloc()) */
649 if (arch_pseudo_atomic_atomic(context)) {
650 store_signal_data_for_later(data,handler,signal,info,context);
651 arch_set_pseudo_atomic_interrupted(context);
652 FSHOW_SIGNAL((stderr,
653 "/maybe_defer_handler(%x,%d): deferred(PA)\n",
654 (unsigned int)handler,signal));
657 FSHOW_SIGNAL((stderr,
658 "/maybe_defer_handler(%x,%d): not deferred\n",
659 (unsigned int)handler,signal));
664 store_signal_data_for_later (struct interrupt_data *data, void *handler,
666 siginfo_t *info, os_context_t *context)
668 if (data->pending_handler)
669 lose("tried to overwrite pending interrupt handler %x with %x\n",
670 data->pending_handler, handler);
672 lose("tried to defer null interrupt handler\n");
673 data->pending_handler = handler;
674 data->pending_signal = signal;
676 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
678 FSHOW_SIGNAL((stderr, "/store_signal_data_for_later: signal: %d\n",
682 /* the signal mask in the context (from before we were
683 * interrupted) is copied to be restored when
684 * run_deferred_handler happens. Then the usually-blocked
685 * signals are added to the mask in the context so that we are
686 * running with blocked signals when the handler returns */
687 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
688 sigaddset_deferrable(os_context_sigmask_addr(context));
693 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
695 os_context_t *context = arch_os_get_context(&void_context);
696 struct thread *thread = arch_os_get_current_thread();
697 struct interrupt_data *data = thread->interrupt_data;
699 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
700 os_restore_fp_control(context);
703 if(!maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
704 interrupt_handle_now(signal, info, context);
708 low_level_interrupt_handle_now(int signal, siginfo_t *info,
709 os_context_t *context)
711 /* No FP control fixage needed, caller has done that. */
712 check_blockables_blocked_or_lose();
713 check_interrupts_enabled_or_lose(context);
714 (*interrupt_low_level_handlers[signal])(signal, info, context);
715 /* No Darwin context fixage needed, caller does that. */
719 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
721 os_context_t *context = arch_os_get_context(&void_context);
722 struct thread *thread = arch_os_get_current_thread();
723 struct interrupt_data *data = thread->interrupt_data;
725 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
726 os_restore_fp_control(context);
729 if(!maybe_defer_handler(low_level_interrupt_handle_now,data,
730 signal,info,context))
731 low_level_interrupt_handle_now(signal, info, context);
735 #ifdef LISP_FEATURE_SB_THREAD
738 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
740 os_context_t *context = arch_os_get_context(&void_context);
742 struct thread *thread=arch_os_get_current_thread();
745 if (arch_pseudo_atomic_atomic(context)) {
746 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
747 arch_set_pseudo_atomic_interrupted(context);
748 FSHOW_SIGNAL((stderr, "sig_stop_for_gc deferred (PA)\n"));
751 else if (SymbolValue(GC_INHIBIT,thread) != NIL) {
752 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
753 FSHOW_SIGNAL((stderr, "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,"suspended\n"));
779 #if defined(SIG_RESUME_FROM_GC)
780 sigaddset(&ss,SIG_RESUME_FROM_GC);
782 sigaddset(&ss,SIG_STOP_FOR_GC);
785 /* It is possible to get SIGCONT (and probably other non-blockable
787 #ifdef SIG_RESUME_FROM_GC
790 do { sigwait(&ss, &sigret); }
791 while (sigret != SIG_RESUME_FROM_GC);
794 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
797 FSHOW_SIGNAL((stderr,"resumed\n"));
798 if(thread->state!=STATE_RUNNING) {
799 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
800 fixnum_value(thread->state));
803 undo_fake_foreign_function_call(context);
808 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
810 os_context_t *context = arch_os_get_context(&void_context);
811 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
812 os_restore_fp_control(context);
813 #ifndef LISP_FEATURE_WIN32
814 if ((signal == SIGILL) || (signal == SIGBUS)
815 #ifndef LISP_FEATURE_LINUX
816 || (signal == SIGEMT)
819 corruption_warning_and_maybe_lose("Signal %d recieved", signal);
822 interrupt_handle_now(signal, info, context);
825 /* manipulate the signal context and stack such that when the handler
826 * returns, it will call function instead of whatever it was doing
830 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
831 extern int *context_eflags_addr(os_context_t *context);
834 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
835 extern void post_signal_tramp(void);
836 extern void call_into_lisp_tramp(void);
838 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
840 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
841 void * fun=native_pointer(function);
842 void *code = &(((struct simple_fun *) fun)->code);
845 /* Build a stack frame showing `interrupted' so that the
846 * user's backtrace makes (as much) sense (as usual) */
848 /* FIXME: what about restoring fp state? */
849 /* FIXME: what about restoring errno? */
850 #ifdef LISP_FEATURE_X86
851 /* Suppose the existence of some function that saved all
852 * registers, called call_into_lisp, then restored GP registers and
853 * returned. It would look something like this:
861 pushl {address of function to call}
862 call 0x8058db0 <call_into_lisp>
869 * What we do here is set up the stack that call_into_lisp would
870 * expect to see if it had been called by this code, and frob the
871 * signal context so that signal return goes directly to call_into_lisp,
872 * and when that function (and the lisp function it invoked) returns,
873 * it returns to the second half of this imaginary function which
874 * restores all registers and returns to C
876 * For this to work, the latter part of the imaginary function
877 * must obviously exist in reality. That would be post_signal_tramp
880 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
882 #if defined(LISP_FEATURE_DARWIN)
883 u32 *register_save_area = (u32 *)os_validate(0, 0x40);
885 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp));
886 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context));
888 /* 1. os_validate (malloc/mmap) register_save_block
889 * 2. copy register state into register_save_block
890 * 3. put a pointer to register_save_block in a register in the context
891 * 4. set the context's EIP to point to a trampoline which:
892 * a. builds the fake stack frame from the block
894 * c. calls the function
897 *register_save_area = *os_context_pc_addr(context);
898 *(register_save_area + 1) = function;
899 *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI);
900 *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI);
901 *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX);
902 *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX);
903 *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX);
904 *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX);
905 *(register_save_area + 8) = *context_eflags_addr(context);
907 *os_context_pc_addr(context) =
908 (os_context_register_t) call_into_lisp_tramp;
909 *os_context_register_addr(context,reg_ECX) =
910 (os_context_register_t) register_save_area;
913 /* return address for call_into_lisp: */
914 *(sp-15) = (u32)post_signal_tramp;
915 *(sp-14) = function; /* args for call_into_lisp : function*/
916 *(sp-13) = 0; /* arg array */
917 *(sp-12) = 0; /* no. args */
918 /* this order matches that used in POPAD */
919 *(sp-11)=*os_context_register_addr(context,reg_EDI);
920 *(sp-10)=*os_context_register_addr(context,reg_ESI);
922 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
923 /* POPAD ignores the value of ESP: */
925 *(sp-7)=*os_context_register_addr(context,reg_EBX);
927 *(sp-6)=*os_context_register_addr(context,reg_EDX);
928 *(sp-5)=*os_context_register_addr(context,reg_ECX);
929 *(sp-4)=*os_context_register_addr(context,reg_EAX);
930 *(sp-3)=*context_eflags_addr(context);
931 *(sp-2)=*os_context_register_addr(context,reg_EBP);
932 *(sp-1)=*os_context_pc_addr(context);
936 #elif defined(LISP_FEATURE_X86_64)
937 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
939 /* return address for call_into_lisp: */
940 *(sp-18) = (u64)post_signal_tramp;
942 *(sp-17)=*os_context_register_addr(context,reg_R15);
943 *(sp-16)=*os_context_register_addr(context,reg_R14);
944 *(sp-15)=*os_context_register_addr(context,reg_R13);
945 *(sp-14)=*os_context_register_addr(context,reg_R12);
946 *(sp-13)=*os_context_register_addr(context,reg_R11);
947 *(sp-12)=*os_context_register_addr(context,reg_R10);
948 *(sp-11)=*os_context_register_addr(context,reg_R9);
949 *(sp-10)=*os_context_register_addr(context,reg_R8);
950 *(sp-9)=*os_context_register_addr(context,reg_RDI);
951 *(sp-8)=*os_context_register_addr(context,reg_RSI);
952 /* skip RBP and RSP */
953 *(sp-7)=*os_context_register_addr(context,reg_RBX);
954 *(sp-6)=*os_context_register_addr(context,reg_RDX);
955 *(sp-5)=*os_context_register_addr(context,reg_RCX);
956 *(sp-4)=*os_context_register_addr(context,reg_RAX);
957 *(sp-3)=*context_eflags_addr(context);
958 *(sp-2)=*os_context_register_addr(context,reg_RBP);
959 *(sp-1)=*os_context_pc_addr(context);
961 *os_context_register_addr(context,reg_RDI) =
962 (os_context_register_t)function; /* function */
963 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
964 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
966 struct thread *th=arch_os_get_current_thread();
967 build_fake_control_stack_frames(th,context);
970 #ifdef LISP_FEATURE_X86
972 #if !defined(LISP_FEATURE_DARWIN)
973 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
974 *os_context_register_addr(context,reg_ECX) = 0;
975 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
977 *os_context_register_addr(context,reg_UESP) =
978 (os_context_register_t)(sp-15);
980 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
981 #endif /* __NETBSD__ */
982 #endif /* LISP_FEATURE_DARWIN */
984 #elif defined(LISP_FEATURE_X86_64)
985 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
986 *os_context_register_addr(context,reg_RCX) = 0;
987 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
988 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
990 /* this much of the calling convention is common to all
992 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
993 *os_context_register_addr(context,reg_NARGS) = 0;
994 *os_context_register_addr(context,reg_LIP) =
995 (os_context_register_t)(unsigned long)code;
996 *os_context_register_addr(context,reg_CFP) =
997 (os_context_register_t)(unsigned long)current_control_frame_pointer;
999 #ifdef ARCH_HAS_NPC_REGISTER
1000 *os_context_npc_addr(context) =
1001 4 + *os_context_pc_addr(context);
1003 #ifdef LISP_FEATURE_SPARC
1004 *os_context_register_addr(context,reg_CODE) =
1005 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
1007 FSHOW((stderr, "/arranged return to Lisp function (0x%lx)\n",
1011 #ifdef LISP_FEATURE_SB_THREAD
1013 /* FIXME: this function can go away when all lisp handlers are invoked
1014 * via arrange_return_to_lisp_function. */
1016 interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
1018 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
1020 FSHOW_SIGNAL((stderr,"/interrupt_thread_handler\n"));
1021 check_blockables_blocked_or_lose();
1023 /* let the handler enable interrupts again when it sees fit */
1024 sigaddset_deferrable(os_context_sigmask_addr(context));
1025 arrange_return_to_lisp_function(context,
1026 StaticSymbolFunction(RUN_INTERRUPTION));
1031 /* KLUDGE: Theoretically the approach we use for undefined alien
1032 * variables should work for functions as well, but on PPC/Darwin
1033 * we get bus error at bogus addresses instead, hence this workaround,
1034 * that has the added benefit of automatically discriminating between
1035 * functions and variables.
1038 undefined_alien_function(void)
1040 funcall0(StaticSymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
1044 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
1046 struct thread *th=arch_os_get_current_thread();
1048 /* note the os_context hackery here. When the signal handler returns,
1049 * it won't go back to what it was doing ... */
1050 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
1051 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1052 /* We hit the end of the control stack: disable guard page
1053 * protection so the error handler has some headroom, protect the
1054 * previous page so that we can catch returns from the guard page
1055 * and restore it. */
1056 corruption_warning_and_maybe_lose("Control stack exhausted");
1057 protect_control_stack_guard_page(0);
1058 protect_control_stack_return_guard_page(1);
1060 arrange_return_to_lisp_function
1061 (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
1064 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
1065 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1066 /* We're returning from the guard page: reprotect it, and
1067 * unprotect this one. This works even if we somehow missed
1068 * the return-guard-page, and hit it on our way to new
1069 * exhaustion instead. */
1070 protect_control_stack_guard_page(1);
1071 protect_control_stack_return_guard_page(0);
1074 else if (addr >= undefined_alien_address &&
1075 addr < undefined_alien_address + os_vm_page_size) {
1076 arrange_return_to_lisp_function
1077 (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
1084 * noise to install handlers
1087 #ifndef LISP_FEATURE_WIN32
1088 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1089 * they are blocked, in Linux 2.6 the default handler is invoked
1090 * instead that usually coredumps. One might hastily think that adding
1091 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1092 * the whole sa_mask is ignored and instead of not adding the signal
1093 * in question to the mask. That means if it's not blockable the
1094 * signal must be unblocked at the beginning of signal handlers.
1096 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1097 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1098 * will be unblocked in the sigmask during the signal handler. -- RMK
1101 static volatile int sigaction_nodefer_works = -1;
1103 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1104 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1107 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1109 sigset_t empty, current;
1111 sigemptyset(&empty);
1112 thread_sigmask(SIG_BLOCK, &empty, ¤t);
1113 /* There should be exactly two blocked signals: the two we added
1114 * to sa_mask when setting up the handler. NetBSD doesn't block
1115 * the signal we're handling when SA_NODEFER is set; Linux before
1116 * 2.6.13 or so also doesn't block the other signal when
1117 * SA_NODEFER is set. */
1118 for(i = 1; i < NSIG; i++)
1119 if (sigismember(¤t, i) !=
1120 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1121 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1122 sigaction_nodefer_works = 0;
1124 if (sigaction_nodefer_works == -1)
1125 sigaction_nodefer_works = 1;
1129 see_if_sigaction_nodefer_works(void)
1131 struct sigaction sa, old_sa;
1133 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1134 sa.sa_sigaction = sigaction_nodefer_test_handler;
1135 sigemptyset(&sa.sa_mask);
1136 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1137 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1138 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1139 /* Make sure no signals are blocked. */
1142 sigemptyset(&empty);
1143 thread_sigmask(SIG_SETMASK, &empty, 0);
1145 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1146 while (sigaction_nodefer_works == -1);
1147 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1150 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1151 #undef SA_NODEFER_TEST_KILL_SIGNAL
1154 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1158 sigemptyset(&unblock);
1159 sigaddset(&unblock, signal);
1160 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1161 interrupt_handle_now_handler(signal, info, void_context);
1165 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1169 sigemptyset(&unblock);
1170 sigaddset(&unblock, signal);
1171 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1172 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1176 undoably_install_low_level_interrupt_handler (int signal,
1177 interrupt_handler_t handler)
1179 struct sigaction sa;
1181 if (0 > signal || signal >= NSIG) {
1182 lose("bad signal number %d\n", signal);
1185 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1186 sa.sa_sigaction = handler;
1187 else if (sigismember(&deferrable_sigset,signal))
1188 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1189 /* The use of a trampoline appears to break the
1190 arch_os_get_context() workaround for SPARC/Linux. For now,
1191 don't use the trampoline (and so be vulnerable to the problems
1192 that SA_NODEFER is meant to solve. */
1193 #if !(defined(LISP_FEATURE_SPARC) && defined(LISP_FEATURE_LINUX))
1194 else if (!sigaction_nodefer_works &&
1195 !sigismember(&blockable_sigset, signal))
1196 sa.sa_sigaction = low_level_unblock_me_trampoline;
1199 sa.sa_sigaction = handler;
1201 sigcopyset(&sa.sa_mask, &blockable_sigset);
1202 sa.sa_flags = SA_SIGINFO | SA_RESTART
1203 | (sigaction_nodefer_works ? SA_NODEFER : 0);
1204 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1205 if((signal==SIG_MEMORY_FAULT)
1206 #ifdef SIG_INTERRUPT_THREAD
1207 || (signal==SIG_INTERRUPT_THREAD)
1210 sa.sa_flags |= SA_ONSTACK;
1213 sigaction(signal, &sa, NULL);
1214 interrupt_low_level_handlers[signal] =
1215 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1219 /* This is called from Lisp. */
1221 install_handler(int signal, void handler(int, siginfo_t*, void*))
1223 #ifndef LISP_FEATURE_WIN32
1224 struct sigaction sa;
1226 union interrupt_handler oldhandler;
1228 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1231 sigaddset(&new, signal);
1232 thread_sigmask(SIG_BLOCK, &new, &old);
1234 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1235 (unsigned int)interrupt_low_level_handlers[signal]));
1236 if (interrupt_low_level_handlers[signal]==0) {
1237 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1238 ARE_SAME_HANDLER(handler, SIG_IGN))
1239 sa.sa_sigaction = handler;
1240 else if (sigismember(&deferrable_sigset, signal))
1241 sa.sa_sigaction = maybe_now_maybe_later;
1242 else if (!sigaction_nodefer_works &&
1243 !sigismember(&blockable_sigset, signal))
1244 sa.sa_sigaction = unblock_me_trampoline;
1246 sa.sa_sigaction = interrupt_handle_now_handler;
1248 sigcopyset(&sa.sa_mask, &blockable_sigset);
1249 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1250 (sigaction_nodefer_works ? SA_NODEFER : 0);
1251 sigaction(signal, &sa, NULL);
1254 oldhandler = interrupt_handlers[signal];
1255 interrupt_handlers[signal].c = handler;
1257 thread_sigmask(SIG_SETMASK, &old, 0);
1259 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1261 return (unsigned long)oldhandler.lisp;
1263 /* Probably-wrong Win32 hack */
1269 interrupt_init(void)
1271 #ifndef LISP_FEATURE_WIN32
1273 SHOW("entering interrupt_init()");
1274 see_if_sigaction_nodefer_works();
1275 sigemptyset(&deferrable_sigset);
1276 sigemptyset(&blockable_sigset);
1277 sigaddset_deferrable(&deferrable_sigset);
1278 sigaddset_blockable(&blockable_sigset);
1280 /* Set up high level handler information. */
1281 for (i = 0; i < NSIG; i++) {
1282 interrupt_handlers[i].c =
1283 /* (The cast here blasts away the distinction between
1284 * SA_SIGACTION-style three-argument handlers and
1285 * signal(..)-style one-argument handlers, which is OK
1286 * because it works to call the 1-argument form where the
1287 * 3-argument form is expected.) */
1288 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1291 SHOW("returning from interrupt_init()");
1295 #ifndef LISP_FEATURE_WIN32
1297 siginfo_code(siginfo_t *info)
1299 return info->si_code;
1301 os_vm_address_t current_memory_fault_address;
1304 lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr)
1306 /* FIXME: This is lossy: if we get another memory fault (eg. from
1307 * another thread) before lisp has read this, we lose the information.
1308 * However, since this is mostly informative, we'll live with that for
1309 * now -- some address is better then no address in this case.
1311 current_memory_fault_address = addr;
1312 /* To allow debugging memory faults in signal handlers and such. */
1313 corruption_warning_and_maybe_lose("Memory fault");
1314 arrange_return_to_lisp_function(context,
1315 StaticSymbolFunction(MEMORY_FAULT_ERROR));
1320 unhandled_trap_error(os_context_t *context)
1322 lispobj context_sap;
1323 fake_foreign_function_call(context);
1324 context_sap = alloc_sap(context);
1325 #ifndef LISP_FEATURE_WIN32
1326 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1328 funcall1(StaticSymbolFunction(UNHANDLED_TRAP_ERROR), context_sap);
1329 lose("UNHANDLED-TRAP-ERROR fell through");
1332 /* Common logic for trapping instructions. How we actually handle each
1333 * case is highly architecture dependent, but the overall shape is
1336 handle_trap(os_context_t *context, int trap)
1339 case trap_PendingInterrupt:
1340 FSHOW((stderr, "/<trap pending interrupt>\n"));
1341 arch_skip_instruction(context);
1342 interrupt_handle_pending(context);
1346 FSHOW((stderr, "/<trap error/cerror %d>\n", trap));
1347 interrupt_internal_error(context, trap==trap_Cerror);
1349 case trap_Breakpoint:
1350 arch_handle_breakpoint(context);
1352 case trap_FunEndBreakpoint:
1353 arch_handle_fun_end_breakpoint(context);
1355 #ifdef trap_AfterBreakpoint
1356 case trap_AfterBreakpoint:
1357 arch_handle_after_breakpoint(context);
1360 #ifdef trap_SingleStepAround
1361 case trap_SingleStepAround:
1362 case trap_SingleStepBefore:
1363 arch_handle_single_step_trap(context, trap);
1367 fake_foreign_function_call(context);
1368 lose("%%PRIMITIVE HALT called; the party is over.\n");
1370 unhandled_trap_error(context);