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"
67 #include "genesis/fdefn.h"
68 #include "genesis/simple-fun.h"
69 #include "genesis/cons.h"
73 static void run_deferred_handler(struct interrupt_data *data, void *v_context);
74 #ifndef LISP_FEATURE_WIN32
75 static void store_signal_data_for_later (struct interrupt_data *data,
76 void *handler, int signal,
78 os_context_t *context);
79 boolean interrupt_maybe_gc_int(int signal, siginfo_t *info, void *v_context);
82 sigaddset_deferrable(sigset_t *s)
86 sigaddset(s, SIGQUIT);
87 sigaddset(s, SIGPIPE);
88 sigaddset(s, SIGALRM);
90 sigaddset(s, SIGTSTP);
91 sigaddset(s, SIGCHLD);
93 sigaddset(s, SIGXCPU);
94 sigaddset(s, SIGXFSZ);
95 sigaddset(s, SIGVTALRM);
96 sigaddset(s, SIGPROF);
97 sigaddset(s, SIGWINCH);
98 sigaddset(s, SIGUSR1);
99 sigaddset(s, SIGUSR2);
100 #ifdef LISP_FEATURE_SB_THREAD
101 sigaddset(s, SIG_INTERRUPT_THREAD);
106 sigaddset_blockable(sigset_t *s)
108 sigaddset_deferrable(s);
109 #ifdef LISP_FEATURE_SB_THREAD
110 sigaddset(s, SIG_STOP_FOR_GC);
114 /* initialized in interrupt_init */
115 static sigset_t deferrable_sigset;
116 static sigset_t blockable_sigset;
120 check_blockables_blocked_or_lose()
122 #ifndef LISP_FEATURE_WIN32
123 /* Get the current sigmask, by blocking the empty set. */
124 sigset_t empty,current;
127 thread_sigmask(SIG_BLOCK, &empty, ¤t);
128 for(i = 1; i < NSIG; i++) {
129 if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i))
130 lose("blockable signal %d not blocked\n",i);
136 check_interrupts_enabled_or_lose(os_context_t *context)
138 struct thread *thread=arch_os_get_current_thread();
139 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
140 lose("interrupts not enabled\n");
142 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
143 (!foreign_function_call_active) &&
145 arch_pseudo_atomic_atomic(context))
146 lose ("in pseudo atomic section\n");
149 /* When we catch an internal error, should we pass it back to Lisp to
150 * be handled in a high-level way? (Early in cold init, the answer is
151 * 'no', because Lisp is still too brain-dead to handle anything.
152 * After sufficient initialization has been completed, the answer
154 boolean internal_errors_enabled = 0;
156 #ifndef LISP_FEATURE_WIN32
157 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*);
159 union interrupt_handler interrupt_handlers[NSIG];
161 /* At the toplevel repl we routinely call this function. The signal
162 * mask ought to be clear anyway most of the time, but may be non-zero
163 * if we were interrupted e.g. while waiting for a queue. */
166 reset_signal_mask(void)
168 #ifndef LISP_FEATURE_WIN32
171 thread_sigmask(SIG_SETMASK,&new,0);
176 block_blockable_signals(void)
178 #ifndef LISP_FEATURE_WIN32
179 thread_sigmask(SIG_BLOCK, &blockable_sigset, 0);
185 * utility routines used by various signal handlers
189 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
191 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
195 /* Build a fake stack frame or frames */
197 current_control_frame_pointer =
198 (lispobj *)(unsigned long)
199 (*os_context_register_addr(context, reg_CSP));
200 if ((lispobj *)(unsigned long)
201 (*os_context_register_addr(context, reg_CFP))
202 == current_control_frame_pointer) {
203 /* There is a small window during call where the callee's
204 * frame isn't built yet. */
205 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
206 == FUN_POINTER_LOWTAG) {
207 /* We have called, but not built the new frame, so
208 * build it for them. */
209 current_control_frame_pointer[0] =
210 *os_context_register_addr(context, reg_OCFP);
211 current_control_frame_pointer[1] =
212 *os_context_register_addr(context, reg_LRA);
213 current_control_frame_pointer += 8;
214 /* Build our frame on top of it. */
215 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
218 /* We haven't yet called, build our frame as if the
219 * partial frame wasn't there. */
220 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
223 /* We can't tell whether we are still in the caller if it had to
224 * allocate a stack frame due to stack arguments. */
225 /* This observation provoked some past CMUCL maintainer to ask
226 * "Can anything strange happen during return?" */
229 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
232 current_control_stack_pointer = current_control_frame_pointer + 8;
234 current_control_frame_pointer[0] = oldcont;
235 current_control_frame_pointer[1] = NIL;
236 current_control_frame_pointer[2] =
237 (lispobj)(*os_context_register_addr(context, reg_CODE));
241 /* Stores the context for gc to scavange and builds fake stack
244 fake_foreign_function_call(os_context_t *context)
247 struct thread *thread=arch_os_get_current_thread();
249 /* context_index incrementing must not be interrupted */
250 check_blockables_blocked_or_lose();
252 /* Get current Lisp state from context. */
254 dynamic_space_free_pointer =
255 (lispobj *)(unsigned long)
256 (*os_context_register_addr(context, reg_ALLOC));
257 #if defined(LISP_FEATURE_ALPHA)
258 if ((long)dynamic_space_free_pointer & 1) {
259 lose("dead in fake_foreign_function_call, context = %x\n", context);
264 current_binding_stack_pointer =
265 (lispobj *)(unsigned long)
266 (*os_context_register_addr(context, reg_BSP));
269 build_fake_control_stack_frames(thread,context);
271 /* Do dynamic binding of the active interrupt context index
272 * and save the context in the context array. */
274 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
276 if (context_index >= MAX_INTERRUPTS) {
277 lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS);
280 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
281 make_fixnum(context_index + 1),thread);
283 thread->interrupt_contexts[context_index] = context;
285 /* no longer in Lisp now */
286 foreign_function_call_active = 1;
289 /* blocks all blockable signals. If you are calling from a signal handler,
290 * the usual signal mask will be restored from the context when the handler
291 * finishes. Otherwise, be careful */
293 undo_fake_foreign_function_call(os_context_t *context)
295 struct thread *thread=arch_os_get_current_thread();
296 /* Block all blockable signals. */
297 block_blockable_signals();
299 /* going back into Lisp */
300 foreign_function_call_active = 0;
302 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
306 /* Put the dynamic space free pointer back into the context. */
307 *os_context_register_addr(context, reg_ALLOC) =
308 (unsigned long) dynamic_space_free_pointer;
312 /* a handler for the signal caused by execution of a trap opcode
313 * signalling an internal error */
315 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
320 fake_foreign_function_call(context);
322 if (!internal_errors_enabled) {
323 describe_internal_error(context);
324 /* There's no good way to recover from an internal error
325 * before the Lisp error handling mechanism is set up. */
326 lose("internal error too early in init, can't recover\n");
329 /* Allocate the SAP object while the interrupts are still
331 context_sap = alloc_sap(context);
333 #ifndef LISP_FEATURE_WIN32
334 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
337 SHOW("in interrupt_internal_error");
339 /* Display some rudimentary debugging information about the
340 * error, so that even if the Lisp error handler gets badly
341 * confused, we have a chance to determine what's going on. */
342 describe_internal_error(context);
344 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
345 continuable ? T : NIL);
347 undo_fake_foreign_function_call(context); /* blocks signals again */
349 arch_skip_instruction(context);
353 interrupt_handle_pending(os_context_t *context)
355 struct thread *thread;
356 struct interrupt_data *data;
358 check_blockables_blocked_or_lose();
360 thread=arch_os_get_current_thread();
361 data=thread->interrupt_data;
363 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
364 /* If pseudo_atomic_interrupted is set then the interrupt is going
365 * to be handled now, ergo it's safe to clear it. */
366 arch_clear_pseudo_atomic_interrupted(context);
369 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
370 #ifdef LISP_FEATURE_SB_THREAD
371 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
372 /* another thread has already initiated a gc, this attempt
373 * might as well be cancelled */
374 SetSymbolValue(GC_PENDING,NIL,thread);
375 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
376 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
379 if (SymbolValue(GC_PENDING,thread) != NIL) {
380 /* GC_PENDING is cleared in SUB-GC, or if another thread
381 * is doing a gc already we will get a SIG_STOP_FOR_GC and
382 * that will clear it. */
383 interrupt_maybe_gc_int(0,NULL,context);
385 check_blockables_blocked_or_lose();
388 /* we may be here only to do the gc stuff, if interrupts are
389 * enabled run the pending handler */
390 if (!((SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) ||
392 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
393 (!foreign_function_call_active) &&
395 arch_pseudo_atomic_atomic(context)))) {
397 /* There may be no pending handler, because it was only a gc
398 * that had to be executed or because pseudo atomic triggered
399 * twice for a single interrupt. For the interested reader,
400 * that may happen if an interrupt hits after the interrupted
401 * flag is cleared but before pseduo-atomic is set and a
402 * pseudo atomic is interrupted in that interrupt. */
403 if (data->pending_handler) {
405 /* If we're here as the result of a pseudo-atomic as opposed
406 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
407 * NIL, because maybe_defer_handler sets
408 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
409 SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
411 #ifndef LISP_FEATURE_WIN32
412 /* restore the saved signal mask from the original signal (the
413 * one that interrupted us during the critical section) into the
414 * os_context for the signal we're currently in the handler for.
415 * This should ensure that when we return from the handler the
416 * blocked signals are unblocked */
417 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
419 sigemptyset(&data->pending_mask);
421 /* This will break on sparc linux: the deferred handler really wants
422 * to be called with a void_context */
423 run_deferred_handler(data,(void *)context);
429 * the two main signal handlers:
430 * interrupt_handle_now(..)
431 * maybe_now_maybe_later(..)
433 * to which we have added interrupt_handle_now_handler(..). Why?
434 * Well, mostly because the SPARC/Linux platform doesn't quite do
435 * signals the way we want them done. The third argument in the
436 * handler isn't filled in by the kernel properly, so we fix it up
437 * ourselves in the arch_os_get_context(..) function; however, we only
438 * want to do this when we first hit the handler, and not when
439 * interrupt_handle_now(..) is being called from some other handler
440 * (when the fixup will already have been done). -- CSR, 2002-07-23
444 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
446 os_context_t *context = (os_context_t*)void_context;
447 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
448 boolean were_in_lisp;
450 union interrupt_handler handler;
451 check_blockables_blocked_or_lose();
452 #ifndef LISP_FEATURE_WIN32
453 if (sigismember(&deferrable_sigset,signal))
454 check_interrupts_enabled_or_lose(context);
457 #ifdef LISP_FEATURE_LINUX
458 /* Under Linux on some architectures, we appear to have to restore
459 the FPU control word from the context, as after the signal is
460 delivered we appear to have a null FPU control word. */
461 os_restore_fp_control(context);
463 handler = interrupt_handlers[signal];
465 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
469 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
470 were_in_lisp = !foreign_function_call_active;
474 fake_foreign_function_call(context);
477 FSHOW_SIGNAL((stderr,
478 "/entering interrupt_handle_now(%d, info, context)\n",
481 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
483 /* This can happen if someone tries to ignore or default one
484 * of the signals we need for runtime support, and the runtime
485 * support decides to pass on it. */
486 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
488 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
489 /* Once we've decided what to do about contexts in a
490 * return-elsewhere world (the original context will no longer
491 * be available; should we copy it or was nobody using it anyway?)
492 * then we should convert this to return-elsewhere */
494 /* CMUCL comment said "Allocate the SAPs while the interrupts
495 * are still disabled.". I (dan, 2003.08.21) assume this is
496 * because we're not in pseudoatomic and allocation shouldn't
497 * be interrupted. In which case it's no longer an issue as
498 * all our allocation from C now goes through a PA wrapper,
499 * but still, doesn't hurt.
501 * Yeah, but non-gencgc platforms don't really wrap allocation
502 * in PA. MG - 2005-08-29 */
504 lispobj info_sap,context_sap = alloc_sap(context);
505 info_sap = alloc_sap(info);
506 /* Leave deferrable signals blocked, the handler itself will
507 * allow signals again when it sees fit. */
508 #ifdef LISP_FEATURE_SB_THREAD
511 sigemptyset(&unblock);
512 sigaddset(&unblock, SIG_STOP_FOR_GC);
513 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
517 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
519 funcall3(handler.lisp,
525 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
527 #ifndef LISP_FEATURE_WIN32
528 /* Allow signals again. */
529 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
532 (*handler.c)(signal, info, void_context);
535 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
539 undo_fake_foreign_function_call(context); /* block signals again */
542 FSHOW_SIGNAL((stderr,
543 "/returning from interrupt_handle_now(%d, info, context)\n",
547 /* This is called at the end of a critical section if the indications
548 * are that some signal was deferred during the section. Note that as
549 * far as C or the kernel is concerned we dealt with the signal
550 * already; we're just doing the Lisp-level processing now that we
553 run_deferred_handler(struct interrupt_data *data, void *v_context) {
554 /* The pending_handler may enable interrupts and then another
555 * interrupt may hit, overwrite interrupt_data, so reset the
556 * pending handler before calling it. Trust the handler to finish
557 * with the siginfo before enabling interrupts. */
558 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
559 data->pending_handler=0;
560 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
563 #ifndef LISP_FEATURE_WIN32
565 maybe_defer_handler(void *handler, struct interrupt_data *data,
566 int signal, siginfo_t *info, os_context_t *context)
568 struct thread *thread=arch_os_get_current_thread();
570 check_blockables_blocked_or_lose();
572 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
573 lose("interrupt already pending\n");
574 /* If interrupts are disabled then INTERRUPT_PENDING is set and
575 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
576 * atomic section inside a WITHOUT-INTERRUPTS.
578 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
579 store_signal_data_for_later(data,handler,signal,info,context);
580 SetSymbolValue(INTERRUPT_PENDING, T,thread);
581 FSHOW_SIGNAL((stderr,
582 "/maybe_defer_handler(%x,%d),thread=%lu: deferred\n",
583 (unsigned int)handler,signal,
584 (unsigned long)thread->os_thread));
587 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
588 * actually use its argument for anything on x86, so this branch
589 * may succeed even when context is null (gencgc alloc()) */
591 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
592 /* FIXME: this foreign_function_call_active test is dubious at
593 * best. If a foreign call is made in a pseudo atomic section
594 * (?) or more likely a pseudo atomic section is in a foreign
595 * call then an interrupt is executed immediately. Maybe it
596 * has to do with C code not maintaining pseudo atomic
597 * properly. MG - 2005-08-10 */
598 (!foreign_function_call_active) &&
600 arch_pseudo_atomic_atomic(context)) {
601 store_signal_data_for_later(data,handler,signal,info,context);
602 arch_set_pseudo_atomic_interrupted(context);
603 FSHOW_SIGNAL((stderr,
604 "/maybe_defer_handler(%x,%d),thread=%lu: deferred(PA)\n",
605 (unsigned int)handler,signal,
606 (unsigned long)thread->os_thread));
609 FSHOW_SIGNAL((stderr,
610 "/maybe_defer_handler(%x,%d),thread=%lu: not deferred\n",
611 (unsigned int)handler,signal,
612 (unsigned long)thread->os_thread));
617 store_signal_data_for_later (struct interrupt_data *data, void *handler,
619 siginfo_t *info, os_context_t *context)
621 if (data->pending_handler)
622 lose("tried to overwrite pending interrupt handler %x with %x\n",
623 data->pending_handler, handler);
625 lose("tried to defer null interrupt handler\n");
626 data->pending_handler = handler;
627 data->pending_signal = signal;
629 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
631 /* the signal mask in the context (from before we were
632 * interrupted) is copied to be restored when
633 * run_deferred_handler happens. Then the usually-blocked
634 * signals are added to the mask in the context so that we are
635 * running with blocked signals when the handler returns */
636 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
637 sigaddset_deferrable(os_context_sigmask_addr(context));
642 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
644 os_context_t *context = arch_os_get_context(&void_context);
645 struct thread *thread=arch_os_get_current_thread();
646 struct interrupt_data *data=thread->interrupt_data;
647 #ifdef LISP_FEATURE_LINUX
648 os_restore_fp_control(context);
650 if(maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
652 interrupt_handle_now(signal, info, context);
653 #ifdef LISP_FEATURE_DARWIN
654 /* Work around G5 bug */
655 DARWIN_FIX_CONTEXT(context);
660 low_level_interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
662 os_context_t *context = (os_context_t*)void_context;
664 #ifdef LISP_FEATURE_LINUX
665 os_restore_fp_control(context);
667 check_blockables_blocked_or_lose();
668 check_interrupts_enabled_or_lose(context);
669 interrupt_low_level_handlers[signal](signal, info, void_context);
670 #ifdef LISP_FEATURE_DARWIN
671 /* Work around G5 bug */
672 DARWIN_FIX_CONTEXT(context);
677 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
679 os_context_t *context = arch_os_get_context(&void_context);
680 struct thread *thread=arch_os_get_current_thread();
681 struct interrupt_data *data=thread->interrupt_data;
682 #ifdef LISP_FEATURE_LINUX
683 os_restore_fp_control(context);
685 if(maybe_defer_handler(low_level_interrupt_handle_now,data,
686 signal,info,context))
688 low_level_interrupt_handle_now(signal, info, context);
689 #ifdef LISP_FEATURE_DARWIN
690 /* Work around G5 bug */
691 DARWIN_FIX_CONTEXT(context);
696 #ifdef LISP_FEATURE_SB_THREAD
699 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
701 os_context_t *context = arch_os_get_context(&void_context);
702 struct thread *thread=arch_os_get_current_thread();
705 if ((arch_pseudo_atomic_atomic(context) ||
706 SymbolValue(GC_INHIBIT,thread) != NIL)) {
707 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
708 if (SymbolValue(GC_INHIBIT,thread) == NIL)
709 arch_set_pseudo_atomic_interrupted(context);
710 FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred\n",
713 /* need the context stored so it can have registers scavenged */
714 fake_foreign_function_call(context);
716 sigfillset(&ss); /* Block everything. */
717 thread_sigmask(SIG_BLOCK,&ss,0);
719 if(thread->state!=STATE_RUNNING) {
720 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
721 fixnum_value(thread->state));
723 thread->state=STATE_SUSPENDED;
724 FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread));
726 sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
727 /* It is possible to get SIGCONT (and probably other
728 * non-blockable signals) here. */
729 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
730 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
731 if(thread->state!=STATE_RUNNING) {
732 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
733 fixnum_value(thread->state));
736 undo_fake_foreign_function_call(context);
742 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
744 os_context_t *context = arch_os_get_context(&void_context);
745 interrupt_handle_now(signal, info, context);
746 #ifdef LISP_FEATURE_DARWIN
747 DARWIN_FIX_CONTEXT(context);
752 * stuff to detect and handle hitting the GC trigger
755 #ifndef LISP_FEATURE_GENCGC
756 /* since GENCGC has its own way to record trigger */
758 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
760 if (current_auto_gc_trigger == NULL)
763 void *badaddr=arch_get_bad_addr(signal,info,context);
764 return (badaddr >= (void *)current_auto_gc_trigger &&
765 badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE));
770 /* manipulate the signal context and stack such that when the handler
771 * returns, it will call function instead of whatever it was doing
775 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
776 extern int *context_eflags_addr(os_context_t *context);
779 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
780 extern void post_signal_tramp(void);
782 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
784 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
785 void * fun=native_pointer(function);
786 void *code = &(((struct simple_fun *) fun)->code);
789 /* Build a stack frame showing `interrupted' so that the
790 * user's backtrace makes (as much) sense (as usual) */
792 /* FIXME: what about restoring fp state? */
793 /* FIXME: what about restoring errno? */
794 #ifdef LISP_FEATURE_X86
795 /* Suppose the existence of some function that saved all
796 * registers, called call_into_lisp, then restored GP registers and
797 * returned. It would look something like this:
805 pushl {address of function to call}
806 call 0x8058db0 <call_into_lisp>
813 * What we do here is set up the stack that call_into_lisp would
814 * expect to see if it had been called by this code, and frob the
815 * signal context so that signal return goes directly to call_into_lisp,
816 * and when that function (and the lisp function it invoked) returns,
817 * it returns to the second half of this imaginary function which
818 * restores all registers and returns to C
820 * For this to work, the latter part of the imaginary function
821 * must obviously exist in reality. That would be post_signal_tramp
824 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
826 /* return address for call_into_lisp: */
827 *(sp-15) = (u32)post_signal_tramp;
828 *(sp-14) = function; /* args for call_into_lisp : function*/
829 *(sp-13) = 0; /* arg array */
830 *(sp-12) = 0; /* no. args */
831 /* this order matches that used in POPAD */
832 *(sp-11)=*os_context_register_addr(context,reg_EDI);
833 *(sp-10)=*os_context_register_addr(context,reg_ESI);
835 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
836 /* POPAD ignores the value of ESP: */
838 *(sp-7)=*os_context_register_addr(context,reg_EBX);
840 *(sp-6)=*os_context_register_addr(context,reg_EDX);
841 *(sp-5)=*os_context_register_addr(context,reg_ECX);
842 *(sp-4)=*os_context_register_addr(context,reg_EAX);
843 *(sp-3)=*context_eflags_addr(context);
844 *(sp-2)=*os_context_register_addr(context,reg_EBP);
845 *(sp-1)=*os_context_pc_addr(context);
847 #elif defined(LISP_FEATURE_X86_64)
848 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
849 /* return address for call_into_lisp: */
850 *(sp-18) = (u64)post_signal_tramp;
852 *(sp-17)=*os_context_register_addr(context,reg_R15);
853 *(sp-16)=*os_context_register_addr(context,reg_R14);
854 *(sp-15)=*os_context_register_addr(context,reg_R13);
855 *(sp-14)=*os_context_register_addr(context,reg_R12);
856 *(sp-13)=*os_context_register_addr(context,reg_R11);
857 *(sp-12)=*os_context_register_addr(context,reg_R10);
858 *(sp-11)=*os_context_register_addr(context,reg_R9);
859 *(sp-10)=*os_context_register_addr(context,reg_R8);
860 *(sp-9)=*os_context_register_addr(context,reg_RDI);
861 *(sp-8)=*os_context_register_addr(context,reg_RSI);
862 /* skip RBP and RSP */
863 *(sp-7)=*os_context_register_addr(context,reg_RBX);
864 *(sp-6)=*os_context_register_addr(context,reg_RDX);
865 *(sp-5)=*os_context_register_addr(context,reg_RCX);
866 *(sp-4)=*os_context_register_addr(context,reg_RAX);
867 *(sp-3)=*context_eflags_addr(context);
868 *(sp-2)=*os_context_register_addr(context,reg_RBP);
869 *(sp-1)=*os_context_pc_addr(context);
871 *os_context_register_addr(context,reg_RDI) =
872 (os_context_register_t)function; /* function */
873 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
874 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
876 struct thread *th=arch_os_get_current_thread();
877 build_fake_control_stack_frames(th,context);
880 #ifdef LISP_FEATURE_X86
881 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
882 *os_context_register_addr(context,reg_ECX) = 0;
883 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
885 *os_context_register_addr(context,reg_UESP) =
886 (os_context_register_t)(sp-15);
888 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
890 #elif defined(LISP_FEATURE_X86_64)
891 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
892 *os_context_register_addr(context,reg_RCX) = 0;
893 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
894 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
896 /* this much of the calling convention is common to all
898 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
899 *os_context_register_addr(context,reg_NARGS) = 0;
900 *os_context_register_addr(context,reg_LIP) =
901 (os_context_register_t)(unsigned long)code;
902 *os_context_register_addr(context,reg_CFP) =
903 (os_context_register_t)(unsigned long)current_control_frame_pointer;
905 #ifdef ARCH_HAS_NPC_REGISTER
906 *os_context_npc_addr(context) =
907 4 + *os_context_pc_addr(context);
909 #ifdef LISP_FEATURE_SPARC
910 *os_context_register_addr(context,reg_CODE) =
911 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
915 #ifdef LISP_FEATURE_SB_THREAD
917 /* FIXME: this function can go away when all lisp handlers are invoked
918 * via arrange_return_to_lisp_function. */
920 interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
922 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
923 /* let the handler enable interrupts again when it sees fit */
924 sigaddset_deferrable(os_context_sigmask_addr(context));
925 arrange_return_to_lisp_function(context, SymbolFunction(RUN_INTERRUPTION));
930 /* KLUDGE: Theoretically the approach we use for undefined alien
931 * variables should work for functions as well, but on PPC/Darwin
932 * we get bus error at bogus addresses instead, hence this workaround,
933 * that has the added benefit of automatically discriminating between
934 * functions and variables.
937 undefined_alien_function() {
938 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
942 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
944 struct thread *th=arch_os_get_current_thread();
946 /* note the os_context hackery here. When the signal handler returns,
947 * it won't go back to what it was doing ... */
948 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
949 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
950 /* We hit the end of the control stack: disable guard page
951 * protection so the error handler has some headroom, protect the
952 * previous page so that we can catch returns from the guard page
954 protect_control_stack_guard_page(0);
955 protect_control_stack_return_guard_page(1);
957 arrange_return_to_lisp_function
958 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
961 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
962 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
963 /* We're returning from the guard page: reprotect it, and
964 * unprotect this one. This works even if we somehow missed
965 * the return-guard-page, and hit it on our way to new
966 * exhaustion instead. */
967 protect_control_stack_guard_page(1);
968 protect_control_stack_return_guard_page(0);
971 else if (addr >= undefined_alien_address &&
972 addr < undefined_alien_address + os_vm_page_size) {
973 arrange_return_to_lisp_function
974 (context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
980 #ifndef LISP_FEATURE_GENCGC
981 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
982 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
983 * whether the signal was due to treading on the mprotect()ed zone -
984 * and if so, arrange for a GC to happen. */
985 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
988 interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
990 os_context_t *context=(os_context_t *) void_context;
992 if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
993 struct thread *thread=arch_os_get_current_thread();
994 clear_auto_gc_trigger();
995 /* Don't flood the system with interrupts if the need to gc is
996 * already noted. This can happen for example when SUB-GC
997 * allocates or after a gc triggered in a WITHOUT-GCING. */
998 if (SymbolValue(GC_PENDING,thread) == NIL) {
999 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
1000 if (arch_pseudo_atomic_atomic(context)) {
1001 /* set things up so that GC happens when we finish
1003 SetSymbolValue(GC_PENDING,T,thread);
1004 arch_set_pseudo_atomic_interrupted(context);
1006 interrupt_maybe_gc_int(signal,info,void_context);
1009 SetSymbolValue(GC_PENDING,T,thread);
1019 /* this is also used by gencgc, in alloc() */
1021 interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
1023 os_context_t *context=(os_context_t *) void_context;
1024 #ifndef LISP_FEATURE_WIN32
1025 struct thread *thread=arch_os_get_current_thread();
1028 fake_foreign_function_call(context);
1030 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
1031 * which case we will be running with no gc trigger barrier
1032 * thing for a while. But it shouldn't be long until the end
1035 * FIXME: It would be good to protect the end of dynamic space
1036 * and signal a storage condition from there.
1039 /* Restore the signal mask from the interrupted context before
1040 * calling into Lisp if interrupts are enabled. Why not always?
1042 * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an
1043 * interrupt hits while in SUB-GC, it is deferred and the
1044 * os_context_sigmask of that interrupt is set to block further
1045 * deferrable interrupts (until the first one is
1046 * handled). Unfortunately, that context refers to this place and
1047 * when we return from here the signals will not be blocked.
1049 * A kludgy alternative is to propagate the sigmask change to the
1052 #ifndef LISP_FEATURE_WIN32
1053 if(SymbolValue(INTERRUPTS_ENABLED,thread)!=NIL)
1054 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1055 #ifdef LISP_FEATURE_SB_THREAD
1059 sigaddset(&new,SIG_STOP_FOR_GC);
1060 thread_sigmask(SIG_UNBLOCK,&new,0);
1064 funcall0(SymbolFunction(SUB_GC));
1066 undo_fake_foreign_function_call(context);
1072 * noise to install handlers
1075 #ifndef LISP_FEATURE_WIN32
1076 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1077 * they are blocked, in Linux 2.6 the default handler is invoked
1078 * instead that usually coredumps. One might hastily think that adding
1079 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1080 * the whole sa_mask is ignored and instead of not adding the signal
1081 * in question to the mask. That means if it's not blockable the
1082 * signal must be unblocked at the beginning of signal handlers.
1084 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1085 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1086 * will be unblocked in the sigmask during the signal handler. -- RMK
1089 static volatile int sigaction_nodefer_works = -1;
1091 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1092 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1095 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1097 sigset_t empty, current;
1099 sigemptyset(&empty);
1100 sigprocmask(SIG_BLOCK, &empty, ¤t);
1101 /* There should be exactly two blocked signals: the two we added
1102 * to sa_mask when setting up the handler. NetBSD doesn't block
1103 * the signal we're handling when SA_NODEFER is set; Linux before
1104 * 2.6.13 or so also doesn't block the other signal when
1105 * SA_NODEFER is set. */
1106 for(i = 1; i < NSIG; i++)
1107 if (sigismember(¤t, i) !=
1108 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1109 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1110 sigaction_nodefer_works = 0;
1112 if (sigaction_nodefer_works == -1)
1113 sigaction_nodefer_works = 1;
1117 see_if_sigaction_nodefer_works()
1119 struct sigaction sa, old_sa;
1121 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1122 sa.sa_sigaction = sigaction_nodefer_test_handler;
1123 sigemptyset(&sa.sa_mask);
1124 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1125 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1126 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1127 /* Make sure no signals are blocked. */
1130 sigemptyset(&empty);
1131 sigprocmask(SIG_SETMASK, &empty, 0);
1133 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1134 while (sigaction_nodefer_works == -1);
1135 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1138 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1139 #undef SA_NODEFER_TEST_KILL_SIGNAL
1142 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1145 sigemptyset(&unblock);
1146 sigaddset(&unblock, signal);
1147 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1148 interrupt_handle_now_handler(signal, info, void_context);
1152 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1155 sigemptyset(&unblock);
1156 sigaddset(&unblock, signal);
1157 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1158 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1162 undoably_install_low_level_interrupt_handler (int signal,
1167 struct sigaction sa;
1169 if (0 > signal || signal >= NSIG) {
1170 lose("bad signal number %d\n", signal);
1173 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1174 sa.sa_sigaction = handler;
1175 else if (sigismember(&deferrable_sigset,signal))
1176 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1177 else if (!sigaction_nodefer_works &&
1178 !sigismember(&blockable_sigset, signal))
1179 sa.sa_sigaction = low_level_unblock_me_trampoline;
1181 sa.sa_sigaction = handler;
1183 sigcopyset(&sa.sa_mask, &blockable_sigset);
1184 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1185 (sigaction_nodefer_works ? SA_NODEFER : 0);
1186 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1187 if((signal==SIG_MEMORY_FAULT)
1188 #ifdef SIG_MEMORY_FAULT2
1189 || (signal==SIG_MEMORY_FAULT2)
1191 #ifdef SIG_INTERRUPT_THREAD
1192 || (signal==SIG_INTERRUPT_THREAD)
1195 sa.sa_flags |= SA_ONSTACK;
1198 sigaction(signal, &sa, NULL);
1199 interrupt_low_level_handlers[signal] =
1200 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1204 /* This is called from Lisp. */
1206 install_handler(int signal, void handler(int, siginfo_t*, void*))
1208 #ifndef LISP_FEATURE_WIN32
1209 struct sigaction sa;
1211 union interrupt_handler oldhandler;
1213 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1216 sigaddset(&new, signal);
1217 thread_sigmask(SIG_BLOCK, &new, &old);
1219 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1220 (unsigned int)interrupt_low_level_handlers[signal]));
1221 if (interrupt_low_level_handlers[signal]==0) {
1222 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1223 ARE_SAME_HANDLER(handler, SIG_IGN))
1224 sa.sa_sigaction = handler;
1225 else if (sigismember(&deferrable_sigset, signal))
1226 sa.sa_sigaction = maybe_now_maybe_later;
1227 else if (!sigaction_nodefer_works &&
1228 !sigismember(&blockable_sigset, signal))
1229 sa.sa_sigaction = unblock_me_trampoline;
1231 sa.sa_sigaction = interrupt_handle_now_handler;
1233 sigcopyset(&sa.sa_mask, &blockable_sigset);
1234 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1235 (sigaction_nodefer_works ? SA_NODEFER : 0);
1236 sigaction(signal, &sa, NULL);
1239 oldhandler = interrupt_handlers[signal];
1240 interrupt_handlers[signal].c = handler;
1242 thread_sigmask(SIG_SETMASK, &old, 0);
1244 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1246 return (unsigned long)oldhandler.lisp;
1248 /* Probably-wrong Win32 hack */
1256 #ifndef LISP_FEATURE_WIN32
1258 SHOW("entering interrupt_init()");
1259 see_if_sigaction_nodefer_works();
1260 sigemptyset(&deferrable_sigset);
1261 sigemptyset(&blockable_sigset);
1262 sigaddset_deferrable(&deferrable_sigset);
1263 sigaddset_blockable(&blockable_sigset);
1265 /* Set up high level handler information. */
1266 for (i = 0; i < NSIG; i++) {
1267 interrupt_handlers[i].c =
1268 /* (The cast here blasts away the distinction between
1269 * SA_SIGACTION-style three-argument handlers and
1270 * signal(..)-style one-argument handlers, which is OK
1271 * because it works to call the 1-argument form where the
1272 * 3-argument form is expected.) */
1273 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1276 SHOW("returning from interrupt_init()");