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 static sigset_t deferrable_sigset;
121 static 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, and alloc() is
399 * always called from within pseudo-atomic, and thus we end up
400 * here again. Third, when calling GC-ON or at the end of a
401 * WITHOUT-GCING, MAYBE-HANDLE-PENDING-GC will trap to here if
402 * there is a pending GC. */
404 /* Win32 only needs to handle the GC cases (for now?) */
406 struct thread *thread;
408 /* Punt if in PA section, marking it as interrupted. This can
409 * happenat least if we pick up a GC request while in a
410 * WITHOUT-GCING with an outer PA -- it is not immediately clear
411 * to me that this should/could ever happen, but better safe then
412 * sorry. --NS 2007-05-15 */
413 if (arch_pseudo_atomic_atomic(context)) {
414 arch_set_pseudo_atomic_interrupted(context);
418 thread = arch_os_get_current_thread();
420 FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n"));
422 check_blockables_blocked_or_lose();
424 /* If pseudo_atomic_interrupted is set then the interrupt is going
425 * to be handled now, ergo it's safe to clear it. */
426 arch_clear_pseudo_atomic_interrupted(context);
428 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
429 #ifdef LISP_FEATURE_SB_THREAD
430 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
431 /* STOP_FOR_GC_PENDING and GC_PENDING are cleared by
432 * the signal handler if it actually stops us. */
433 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
436 if (SymbolValue(GC_PENDING,thread) != NIL) {
437 /* GC_PENDING is cleared in SUB-GC, or if another thread
438 * is doing a gc already we will get a SIG_STOP_FOR_GC and
439 * that will clear it. */
442 check_blockables_blocked_or_lose();
445 #ifndef LISP_FEATURE_WIN32
446 /* we may be here only to do the gc stuff, if interrupts are
447 * enabled run the pending handler */
448 if (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) {
449 struct interrupt_data *data = thread->interrupt_data;
451 /* There may be no pending handler, because it was only a gc
452 * that had to be executed or because pseudo atomic triggered
453 * twice for a single interrupt. For the interested reader,
454 * that may happen if an interrupt hits after the interrupted
455 * flag is cleared but before pseudo-atomic is set and a
456 * pseudo atomic is interrupted in that interrupt. */
457 if (data->pending_handler) {
459 /* If we're here as the result of a pseudo-atomic as opposed
460 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
461 * NIL, because maybe_defer_handler sets
462 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
463 SetSymbolValue(INTERRUPT_PENDING, NIL, thread);
465 /* restore the saved signal mask from the original signal (the
466 * one that interrupted us during the critical section) into the
467 * os_context for the signal we're currently in the handler for.
468 * This should ensure that when we return from the handler the
469 * blocked signals are unblocked */
470 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
472 sigemptyset(&data->pending_mask);
473 /* This will break on sparc linux: the deferred handler really wants
474 * to be called with a void_context */
475 run_deferred_handler(data,(void *)context);
482 * the two main signal handlers:
483 * interrupt_handle_now(..)
484 * maybe_now_maybe_later(..)
486 * to which we have added interrupt_handle_now_handler(..). Why?
487 * Well, mostly because the SPARC/Linux platform doesn't quite do
488 * signals the way we want them done. The third argument in the
489 * handler isn't filled in by the kernel properly, so we fix it up
490 * ourselves in the arch_os_get_context(..) function; however, we only
491 * want to do this when we first hit the handler, and not when
492 * interrupt_handle_now(..) is being called from some other handler
493 * (when the fixup will already have been done). -- CSR, 2002-07-23
497 interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
499 #ifdef FOREIGN_FUNCTION_CALL_FLAG
500 boolean were_in_lisp;
502 union interrupt_handler handler;
504 check_blockables_blocked_or_lose();
506 #ifndef LISP_FEATURE_WIN32
507 if (sigismember(&deferrable_sigset,signal))
508 check_interrupts_enabled_or_lose(context);
511 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
512 /* Under Linux on some architectures, we appear to have to restore
513 the FPU control word from the context, as after the signal is
514 delivered we appear to have a null FPU control word. */
515 os_restore_fp_control(context);
518 handler = interrupt_handlers[signal];
520 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
524 #ifdef FOREIGN_FUNCTION_CALL_FLAG
525 were_in_lisp = !foreign_function_call_active;
529 fake_foreign_function_call(context);
532 FSHOW_SIGNAL((stderr,
533 "/entering interrupt_handle_now(%d, info, context)\n",
536 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
538 /* This can happen if someone tries to ignore or default one
539 * of the signals we need for runtime support, and the runtime
540 * support decides to pass on it. */
541 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
543 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
544 /* Once we've decided what to do about contexts in a
545 * return-elsewhere world (the original context will no longer
546 * be available; should we copy it or was nobody using it anyway?)
547 * then we should convert this to return-elsewhere */
549 /* CMUCL comment said "Allocate the SAPs while the interrupts
550 * are still disabled.". I (dan, 2003.08.21) assume this is
551 * because we're not in pseudoatomic and allocation shouldn't
552 * be interrupted. In which case it's no longer an issue as
553 * all our allocation from C now goes through a PA wrapper,
554 * but still, doesn't hurt.
556 * Yeah, but non-gencgc platforms don't really wrap allocation
557 * in PA. MG - 2005-08-29 */
559 lispobj info_sap,context_sap = alloc_sap(context);
560 info_sap = alloc_sap(info);
561 /* Leave deferrable signals blocked, the handler itself will
562 * allow signals again when it sees fit. */
563 #ifdef LISP_FEATURE_SB_THREAD
566 sigemptyset(&unblock);
567 sigaddset(&unblock, SIG_STOP_FOR_GC);
568 #ifdef SIG_RESUME_FROM_GC
569 sigaddset(&unblock, SIG_RESUME_FROM_GC);
571 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
575 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
577 funcall3(handler.lisp,
583 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
585 #ifndef LISP_FEATURE_WIN32
586 /* Allow signals again. */
587 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
589 (*handler.c)(signal, info, context);
592 #ifdef FOREIGN_FUNCTION_CALL_FLAG
596 undo_fake_foreign_function_call(context); /* block signals again */
599 FSHOW_SIGNAL((stderr,
600 "/returning from interrupt_handle_now(%d, info, context)\n",
604 /* This is called at the end of a critical section if the indications
605 * are that some signal was deferred during the section. Note that as
606 * far as C or the kernel is concerned we dealt with the signal
607 * already; we're just doing the Lisp-level processing now that we
610 run_deferred_handler(struct interrupt_data *data, void *v_context)
612 /* The pending_handler may enable interrupts and then another
613 * interrupt may hit, overwrite interrupt_data, so reset the
614 * pending handler before calling it. Trust the handler to finish
615 * with the siginfo before enabling interrupts. */
616 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
618 data->pending_handler=0;
619 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
622 #ifndef LISP_FEATURE_WIN32
624 maybe_defer_handler(void *handler, struct interrupt_data *data,
625 int signal, siginfo_t *info, os_context_t *context)
627 struct thread *thread=arch_os_get_current_thread();
629 check_blockables_blocked_or_lose();
631 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
632 lose("interrupt already pending\n");
633 /* If interrupts are disabled then INTERRUPT_PENDING is set and
634 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
635 * atomic section inside a WITHOUT-INTERRUPTS.
637 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
638 store_signal_data_for_later(data,handler,signal,info,context);
639 SetSymbolValue(INTERRUPT_PENDING, T,thread);
640 FSHOW_SIGNAL((stderr,
641 "/maybe_defer_handler(%x,%d),thread=%lu: deferred\n",
642 (unsigned int)handler,signal,
643 (unsigned long)thread->os_thread));
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),thread=%lu: deferred(PA)\n",
654 (unsigned int)handler,signal,
655 (unsigned long)thread->os_thread));
658 FSHOW_SIGNAL((stderr,
659 "/maybe_defer_handler(%x,%d),thread=%lu: not deferred\n",
660 (unsigned int)handler,signal,
661 (unsigned long)thread->os_thread));
666 store_signal_data_for_later (struct interrupt_data *data, void *handler,
668 siginfo_t *info, os_context_t *context)
670 if (data->pending_handler)
671 lose("tried to overwrite pending interrupt handler %x with %x\n",
672 data->pending_handler, handler);
674 lose("tried to defer null interrupt handler\n");
675 data->pending_handler = handler;
676 data->pending_signal = signal;
678 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
680 FSHOW_SIGNAL((stderr, "/store_signal_data_for_later: signal: %d\n",
684 /* the signal mask in the context (from before we were
685 * interrupted) is copied to be restored when
686 * run_deferred_handler happens. Then the usually-blocked
687 * signals are added to the mask in the context so that we are
688 * running with blocked signals when the handler returns */
689 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
690 sigaddset_deferrable(os_context_sigmask_addr(context));
695 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
697 os_context_t *context = arch_os_get_context(&void_context);
698 struct thread *thread = arch_os_get_current_thread();
699 struct interrupt_data *data = thread->interrupt_data;
701 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
702 os_restore_fp_control(context);
705 if(!maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
706 interrupt_handle_now(signal, info, context);
710 low_level_interrupt_handle_now(int signal, siginfo_t *info,
711 os_context_t *context)
713 /* No FP control fixage needed, caller has done that. */
714 check_blockables_blocked_or_lose();
715 check_interrupts_enabled_or_lose(context);
716 interrupt_low_level_handlers[signal](signal, info, context);
717 /* No Darwin context fixage needed, caller does that. */
721 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
723 os_context_t *context = arch_os_get_context(&void_context);
724 struct thread *thread = arch_os_get_current_thread();
725 struct interrupt_data *data = thread->interrupt_data;
727 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
728 os_restore_fp_control(context);
731 if(!maybe_defer_handler(low_level_interrupt_handle_now,data,
732 signal,info,context))
733 low_level_interrupt_handle_now(signal, info, context);
737 #ifdef LISP_FEATURE_SB_THREAD
740 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
742 os_context_t *context = arch_os_get_context(&void_context);
744 struct thread *thread=arch_os_get_current_thread();
747 if (arch_pseudo_atomic_atomic(context)) {
748 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
749 arch_set_pseudo_atomic_interrupted(context);
750 FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred (PA)\n",
754 else if (SymbolValue(GC_INHIBIT,thread) != NIL) {
755 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
756 FSHOW_SIGNAL((stderr,
757 "thread=%lu sig_stop_for_gc deferred (*GC-INHIBIT*)\n",
762 /* Not PA and GC not inhibited -- we can stop now. */
764 /* need the context stored so it can have registers scavenged */
765 fake_foreign_function_call(context);
767 /* Block everything. */
769 thread_sigmask(SIG_BLOCK,&ss,0);
771 /* Not pending anymore. */
772 SetSymbolValue(GC_PENDING,NIL,thread);
773 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
775 if(thread->state!=STATE_RUNNING) {
776 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
777 fixnum_value(thread->state));
780 thread->state=STATE_SUSPENDED;
781 FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread));
784 #if defined(SIG_RESUME_FROM_GC)
785 sigaddset(&ss,SIG_RESUME_FROM_GC);
787 sigaddset(&ss,SIG_STOP_FOR_GC);
790 /* It is possible to get SIGCONT (and probably other non-blockable
792 #ifdef SIG_RESUME_FROM_GC
795 do { sigwait(&ss, &sigret); }
796 while (sigret != SIG_RESUME_FROM_GC);
799 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
802 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
803 if(thread->state!=STATE_RUNNING) {
804 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
805 fixnum_value(thread->state));
808 undo_fake_foreign_function_call(context);
813 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
815 os_context_t *context = arch_os_get_context(&void_context);
816 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
817 os_restore_fp_control(context);
819 interrupt_handle_now(signal, info, context);
822 /* manipulate the signal context and stack such that when the handler
823 * returns, it will call function instead of whatever it was doing
827 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
828 extern int *context_eflags_addr(os_context_t *context);
831 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
832 extern void post_signal_tramp(void);
833 extern void call_into_lisp_tramp(void);
835 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
837 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
838 void * fun=native_pointer(function);
839 void *code = &(((struct simple_fun *) fun)->code);
842 /* Build a stack frame showing `interrupted' so that the
843 * user's backtrace makes (as much) sense (as usual) */
845 /* FIXME: what about restoring fp state? */
846 /* FIXME: what about restoring errno? */
847 #ifdef LISP_FEATURE_X86
848 /* Suppose the existence of some function that saved all
849 * registers, called call_into_lisp, then restored GP registers and
850 * returned. It would look something like this:
858 pushl {address of function to call}
859 call 0x8058db0 <call_into_lisp>
866 * What we do here is set up the stack that call_into_lisp would
867 * expect to see if it had been called by this code, and frob the
868 * signal context so that signal return goes directly to call_into_lisp,
869 * and when that function (and the lisp function it invoked) returns,
870 * it returns to the second half of this imaginary function which
871 * restores all registers and returns to C
873 * For this to work, the latter part of the imaginary function
874 * must obviously exist in reality. That would be post_signal_tramp
877 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
879 #if defined(LISP_FEATURE_DARWIN)
880 u32 *register_save_area = (u32 *)os_validate(0, 0x40);
882 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp));
883 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context));
885 /* 1. os_validate (malloc/mmap) register_save_block
886 * 2. copy register state into register_save_block
887 * 3. put a pointer to register_save_block in a register in the context
888 * 4. set the context's EIP to point to a trampoline which:
889 * a. builds the fake stack frame from the block
891 * c. calls the function
894 *register_save_area = *os_context_pc_addr(context);
895 *(register_save_area + 1) = function;
896 *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI);
897 *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI);
898 *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX);
899 *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX);
900 *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX);
901 *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX);
902 *(register_save_area + 8) = *context_eflags_addr(context);
904 *os_context_pc_addr(context) =
905 (os_context_register_t) call_into_lisp_tramp;
906 *os_context_register_addr(context,reg_ECX) =
907 (os_context_register_t) register_save_area;
910 /* return address for call_into_lisp: */
911 *(sp-15) = (u32)post_signal_tramp;
912 *(sp-14) = function; /* args for call_into_lisp : function*/
913 *(sp-13) = 0; /* arg array */
914 *(sp-12) = 0; /* no. args */
915 /* this order matches that used in POPAD */
916 *(sp-11)=*os_context_register_addr(context,reg_EDI);
917 *(sp-10)=*os_context_register_addr(context,reg_ESI);
919 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
920 /* POPAD ignores the value of ESP: */
922 *(sp-7)=*os_context_register_addr(context,reg_EBX);
924 *(sp-6)=*os_context_register_addr(context,reg_EDX);
925 *(sp-5)=*os_context_register_addr(context,reg_ECX);
926 *(sp-4)=*os_context_register_addr(context,reg_EAX);
927 *(sp-3)=*context_eflags_addr(context);
928 *(sp-2)=*os_context_register_addr(context,reg_EBP);
929 *(sp-1)=*os_context_pc_addr(context);
933 #elif defined(LISP_FEATURE_X86_64)
934 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
936 /* return address for call_into_lisp: */
937 *(sp-18) = (u64)post_signal_tramp;
939 *(sp-17)=*os_context_register_addr(context,reg_R15);
940 *(sp-16)=*os_context_register_addr(context,reg_R14);
941 *(sp-15)=*os_context_register_addr(context,reg_R13);
942 *(sp-14)=*os_context_register_addr(context,reg_R12);
943 *(sp-13)=*os_context_register_addr(context,reg_R11);
944 *(sp-12)=*os_context_register_addr(context,reg_R10);
945 *(sp-11)=*os_context_register_addr(context,reg_R9);
946 *(sp-10)=*os_context_register_addr(context,reg_R8);
947 *(sp-9)=*os_context_register_addr(context,reg_RDI);
948 *(sp-8)=*os_context_register_addr(context,reg_RSI);
949 /* skip RBP and RSP */
950 *(sp-7)=*os_context_register_addr(context,reg_RBX);
951 *(sp-6)=*os_context_register_addr(context,reg_RDX);
952 *(sp-5)=*os_context_register_addr(context,reg_RCX);
953 *(sp-4)=*os_context_register_addr(context,reg_RAX);
954 *(sp-3)=*context_eflags_addr(context);
955 *(sp-2)=*os_context_register_addr(context,reg_RBP);
956 *(sp-1)=*os_context_pc_addr(context);
958 *os_context_register_addr(context,reg_RDI) =
959 (os_context_register_t)function; /* function */
960 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
961 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
963 struct thread *th=arch_os_get_current_thread();
964 build_fake_control_stack_frames(th,context);
967 #ifdef LISP_FEATURE_X86
969 #if !defined(LISP_FEATURE_DARWIN)
970 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
971 *os_context_register_addr(context,reg_ECX) = 0;
972 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
974 *os_context_register_addr(context,reg_UESP) =
975 (os_context_register_t)(sp-15);
977 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
978 #endif /* __NETBSD__ */
979 #endif /* LISP_FEATURE_DARWIN */
981 #elif defined(LISP_FEATURE_X86_64)
982 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
983 *os_context_register_addr(context,reg_RCX) = 0;
984 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
985 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
987 /* this much of the calling convention is common to all
989 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
990 *os_context_register_addr(context,reg_NARGS) = 0;
991 *os_context_register_addr(context,reg_LIP) =
992 (os_context_register_t)(unsigned long)code;
993 *os_context_register_addr(context,reg_CFP) =
994 (os_context_register_t)(unsigned long)current_control_frame_pointer;
996 #ifdef ARCH_HAS_NPC_REGISTER
997 *os_context_npc_addr(context) =
998 4 + *os_context_pc_addr(context);
1000 #ifdef LISP_FEATURE_SPARC
1001 *os_context_register_addr(context,reg_CODE) =
1002 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
1006 #ifdef LISP_FEATURE_SB_THREAD
1008 /* FIXME: this function can go away when all lisp handlers are invoked
1009 * via arrange_return_to_lisp_function. */
1011 interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
1013 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
1015 /* let the handler enable interrupts again when it sees fit */
1016 sigaddset_deferrable(os_context_sigmask_addr(context));
1017 arrange_return_to_lisp_function(context,
1018 StaticSymbolFunction(RUN_INTERRUPTION));
1023 /* KLUDGE: Theoretically the approach we use for undefined alien
1024 * variables should work for functions as well, but on PPC/Darwin
1025 * we get bus error at bogus addresses instead, hence this workaround,
1026 * that has the added benefit of automatically discriminating between
1027 * functions and variables.
1030 undefined_alien_function(void)
1032 funcall0(StaticSymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
1036 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
1038 struct thread *th=arch_os_get_current_thread();
1040 /* note the os_context hackery here. When the signal handler returns,
1041 * it won't go back to what it was doing ... */
1042 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
1043 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1044 /* We hit the end of the control stack: disable guard page
1045 * protection so the error handler has some headroom, protect the
1046 * previous page so that we can catch returns from the guard page
1047 * and restore it. */
1048 protect_control_stack_guard_page(0);
1049 protect_control_stack_return_guard_page(1);
1051 arrange_return_to_lisp_function
1052 (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
1055 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
1056 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1057 /* We're returning from the guard page: reprotect it, and
1058 * unprotect this one. This works even if we somehow missed
1059 * the return-guard-page, and hit it on our way to new
1060 * exhaustion instead. */
1061 protect_control_stack_guard_page(1);
1062 protect_control_stack_return_guard_page(0);
1065 else if (addr >= undefined_alien_address &&
1066 addr < undefined_alien_address + os_vm_page_size) {
1067 arrange_return_to_lisp_function
1068 (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
1075 * noise to install handlers
1078 #ifndef LISP_FEATURE_WIN32
1079 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1080 * they are blocked, in Linux 2.6 the default handler is invoked
1081 * instead that usually coredumps. One might hastily think that adding
1082 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1083 * the whole sa_mask is ignored and instead of not adding the signal
1084 * in question to the mask. That means if it's not blockable the
1085 * signal must be unblocked at the beginning of signal handlers.
1087 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1088 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1089 * will be unblocked in the sigmask during the signal handler. -- RMK
1092 static volatile int sigaction_nodefer_works = -1;
1094 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1095 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1098 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1100 sigset_t empty, current;
1102 sigemptyset(&empty);
1103 thread_sigmask(SIG_BLOCK, &empty, ¤t);
1104 /* There should be exactly two blocked signals: the two we added
1105 * to sa_mask when setting up the handler. NetBSD doesn't block
1106 * the signal we're handling when SA_NODEFER is set; Linux before
1107 * 2.6.13 or so also doesn't block the other signal when
1108 * SA_NODEFER is set. */
1109 for(i = 1; i < NSIG; i++)
1110 if (sigismember(¤t, i) !=
1111 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1112 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1113 sigaction_nodefer_works = 0;
1115 if (sigaction_nodefer_works == -1)
1116 sigaction_nodefer_works = 1;
1120 see_if_sigaction_nodefer_works(void)
1122 struct sigaction sa, old_sa;
1124 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1125 sa.sa_sigaction = sigaction_nodefer_test_handler;
1126 sigemptyset(&sa.sa_mask);
1127 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1128 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1129 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1130 /* Make sure no signals are blocked. */
1133 sigemptyset(&empty);
1134 thread_sigmask(SIG_SETMASK, &empty, 0);
1136 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1137 while (sigaction_nodefer_works == -1);
1138 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1141 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1142 #undef SA_NODEFER_TEST_KILL_SIGNAL
1145 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1149 sigemptyset(&unblock);
1150 sigaddset(&unblock, signal);
1151 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1152 interrupt_handle_now_handler(signal, info, void_context);
1156 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1160 sigemptyset(&unblock);
1161 sigaddset(&unblock, signal);
1162 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1163 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1167 undoably_install_low_level_interrupt_handler (int signal,
1168 interrupt_handler_t handler)
1170 struct sigaction sa;
1172 if (0 > signal || signal >= NSIG) {
1173 lose("bad signal number %d\n", signal);
1176 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1177 sa.sa_sigaction = handler;
1178 else if (sigismember(&deferrable_sigset,signal))
1179 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1180 /* The use of a trampoline appears to break the
1181 arch_os_get_context() workaround for SPARC/Linux. For now,
1182 don't use the trampoline (and so be vulnerable to the problems
1183 that SA_NODEFER is meant to solve. */
1184 #if !(defined(LISP_FEATURE_SPARC) && defined(LISP_FEATURE_LINUX))
1185 else if (!sigaction_nodefer_works &&
1186 !sigismember(&blockable_sigset, signal))
1187 sa.sa_sigaction = low_level_unblock_me_trampoline;
1190 sa.sa_sigaction = handler;
1192 sigcopyset(&sa.sa_mask, &blockable_sigset);
1193 sa.sa_flags = SA_SIGINFO | SA_RESTART
1194 | (sigaction_nodefer_works ? SA_NODEFER : 0);
1195 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1196 if((signal==SIG_MEMORY_FAULT)
1197 #ifdef SIG_INTERRUPT_THREAD
1198 || (signal==SIG_INTERRUPT_THREAD)
1201 sa.sa_flags |= SA_ONSTACK;
1204 sigaction(signal, &sa, NULL);
1205 interrupt_low_level_handlers[signal] =
1206 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1210 /* This is called from Lisp. */
1212 install_handler(int signal, void handler(int, siginfo_t*, void*))
1214 #ifndef LISP_FEATURE_WIN32
1215 struct sigaction sa;
1217 union interrupt_handler oldhandler;
1219 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1222 sigaddset(&new, signal);
1223 thread_sigmask(SIG_BLOCK, &new, &old);
1225 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1226 (unsigned int)interrupt_low_level_handlers[signal]));
1227 if (interrupt_low_level_handlers[signal]==0) {
1228 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1229 ARE_SAME_HANDLER(handler, SIG_IGN))
1230 sa.sa_sigaction = handler;
1231 else if (sigismember(&deferrable_sigset, signal))
1232 sa.sa_sigaction = maybe_now_maybe_later;
1233 else if (!sigaction_nodefer_works &&
1234 !sigismember(&blockable_sigset, signal))
1235 sa.sa_sigaction = unblock_me_trampoline;
1237 sa.sa_sigaction = interrupt_handle_now_handler;
1239 sigcopyset(&sa.sa_mask, &blockable_sigset);
1240 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1241 (sigaction_nodefer_works ? SA_NODEFER : 0);
1242 sigaction(signal, &sa, NULL);
1245 oldhandler = interrupt_handlers[signal];
1246 interrupt_handlers[signal].c = handler;
1248 thread_sigmask(SIG_SETMASK, &old, 0);
1250 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1252 return (unsigned long)oldhandler.lisp;
1254 /* Probably-wrong Win32 hack */
1260 interrupt_init(void)
1262 #ifndef LISP_FEATURE_WIN32
1264 SHOW("entering interrupt_init()");
1265 see_if_sigaction_nodefer_works();
1266 sigemptyset(&deferrable_sigset);
1267 sigemptyset(&blockable_sigset);
1268 sigaddset_deferrable(&deferrable_sigset);
1269 sigaddset_blockable(&blockable_sigset);
1271 /* Set up high level handler information. */
1272 for (i = 0; i < NSIG; i++) {
1273 interrupt_handlers[i].c =
1274 /* (The cast here blasts away the distinction between
1275 * SA_SIGACTION-style three-argument handlers and
1276 * signal(..)-style one-argument handlers, which is OK
1277 * because it works to call the 1-argument form where the
1278 * 3-argument form is expected.) */
1279 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1282 SHOW("returning from interrupt_init()");
1286 #ifndef LISP_FEATURE_WIN32
1288 siginfo_code(siginfo_t *info)
1290 return info->si_code;
1292 os_vm_address_t current_memory_fault_address;
1295 lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr)
1297 /* FIXME: This is lossy: if we get another memory fault (eg. from
1298 * another thread) before lisp has read this, we lose the information.
1299 * However, since this is mostly informative, we'll live with that for
1300 * now -- some address is better then no address in this case.
1302 current_memory_fault_address = addr;
1303 arrange_return_to_lisp_function(context,
1304 StaticSymbolFunction(MEMORY_FAULT_ERROR));
1309 unhandled_trap_error(os_context_t *context)
1311 lispobj context_sap;
1312 fake_foreign_function_call(context);
1313 context_sap = alloc_sap(context);
1314 #ifndef LISP_FEATURE_WIN32
1315 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1317 funcall1(StaticSymbolFunction(UNHANDLED_TRAP_ERROR), context_sap);
1318 lose("UNHANDLED-TRAP-ERROR fell through");
1321 /* Common logic for trapping instructions. How we actually handle each
1322 * case is highly architecture dependent, but the overall shape is
1325 handle_trap(os_context_t *context, int trap)
1328 case trap_PendingInterrupt:
1329 FSHOW((stderr, "/<trap pending interrupt>\n"));
1330 arch_skip_instruction(context);
1331 interrupt_handle_pending(context);
1335 FSHOW((stderr, "/<trap error/cerror %d>\n", trap));
1336 interrupt_internal_error(context, trap==trap_Cerror);
1338 case trap_Breakpoint:
1339 arch_handle_breakpoint(context);
1341 case trap_FunEndBreakpoint:
1342 arch_handle_fun_end_breakpoint(context);
1344 #ifdef trap_AfterBreakpoint
1345 case trap_AfterBreakpoint:
1346 arch_handle_after_breakpoint(context);
1349 #ifdef trap_SingleStepAround
1350 case trap_SingleStepAround:
1351 case trap_SingleStepBefore:
1352 arch_handle_single_step_trap(context, trap);
1356 fake_foreign_function_call(context);
1357 lose("%%PRIMITIVE HALT called; the party is over.\n");
1359 unhandled_trap_error(context);