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", dynamic_space_free_pointer); */
281 #if defined(LISP_FEATURE_ALPHA) || defined(LISP_FEATURE_MIPS)
282 if ((long)dynamic_space_free_pointer & 1) {
283 lose("dead in fake_foreign_function_call, context = %x\n", context);
286 /* why doesnt PPC and SPARC do something like this: */
287 #if defined(LISP_FEATURE_HPPA)
288 if ((long)dynamic_space_free_pointer & 4) {
289 lose("dead in fake_foreign_function_call, context = %x, d_s_f_p = %x\n", context, dynamic_space_free_pointer);
294 current_binding_stack_pointer =
295 (lispobj *)(unsigned long)
296 (*os_context_register_addr(context, reg_BSP));
299 build_fake_control_stack_frames(thread,context);
301 /* Do dynamic binding of the active interrupt context index
302 * and save the context in the context array. */
304 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
306 if (context_index >= MAX_INTERRUPTS) {
307 lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS);
310 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
311 make_fixnum(context_index + 1),thread);
313 thread->interrupt_contexts[context_index] = context;
315 #ifdef FOREIGN_FUNCTION_CALL_FLAG
316 foreign_function_call_active = 1;
320 /* blocks all blockable signals. If you are calling from a signal handler,
321 * the usual signal mask will be restored from the context when the handler
322 * finishes. Otherwise, be careful */
324 undo_fake_foreign_function_call(os_context_t *context)
326 struct thread *thread=arch_os_get_current_thread();
327 /* Block all blockable signals. */
328 block_blockable_signals();
330 #ifdef FOREIGN_FUNCTION_CALL_FLAG
331 foreign_function_call_active = 0;
334 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
338 /* Put the dynamic space free pointer back into the context. */
339 *os_context_register_addr(context, reg_ALLOC) =
340 (unsigned long) dynamic_space_free_pointer
341 | (*os_context_register_addr(context, reg_ALLOC)
344 ((unsigned long)(*os_context_register_addr(context, reg_ALLOC)) & ~LOWTAG_MASK)
345 | ((unsigned long) dynamic_space_free_pointer & LOWTAG_MASK);
350 /* a handler for the signal caused by execution of a trap opcode
351 * signalling an internal error */
353 interrupt_internal_error(os_context_t *context, boolean continuable)
357 fake_foreign_function_call(context);
359 if (!internal_errors_enabled) {
360 describe_internal_error(context);
361 /* There's no good way to recover from an internal error
362 * before the Lisp error handling mechanism is set up. */
363 lose("internal error too early in init, can't recover\n");
366 /* Allocate the SAP object while the interrupts are still
368 context_sap = alloc_sap(context);
370 #ifndef LISP_FEATURE_WIN32
371 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
374 SHOW("in interrupt_internal_error");
376 /* Display some rudimentary debugging information about the
377 * error, so that even if the Lisp error handler gets badly
378 * confused, we have a chance to determine what's going on. */
379 describe_internal_error(context);
381 funcall2(StaticSymbolFunction(INTERNAL_ERROR), context_sap,
382 continuable ? T : NIL);
384 undo_fake_foreign_function_call(context); /* blocks signals again */
386 arch_skip_instruction(context);
390 interrupt_handle_pending(os_context_t *context)
392 /* There are three ways we can get here. First, if an interrupt
393 * occurs within pseudo-atomic, it will be deferred, and we'll
394 * trap to here at the end of the pseudo-atomic block. Second, if
395 * the GC (in alloc()) decides that a GC is required, it will set
396 * *GC-PENDING* and pseudo-atomic-interrupted, and alloc() is
397 * always called from within pseudo-atomic, and thus we end up
398 * here again. Third, when calling GC-ON or at the end of a
399 * WITHOUT-GCING, MAYBE-HANDLE-PENDING-GC will trap to here if
400 * there is a pending GC. */
402 /* Win32 only needs to handle the GC cases (for now?) */
404 struct thread *thread;
406 /* Punt if in PA section, marking it as interrupted. This can
407 * happenat least if we pick up a GC request while in a
408 * WITHOUT-GCING with an outer PA -- it is not immediately clear
409 * to me that this should/could ever happen, but better safe then
410 * sorry. --NS 2007-05-15 */
411 if (arch_pseudo_atomic_atomic(context)) {
412 arch_set_pseudo_atomic_interrupted(context);
416 thread = arch_os_get_current_thread();
418 FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n"));
420 check_blockables_blocked_or_lose();
422 /* If pseudo_atomic_interrupted is set then the interrupt is going
423 * to be handled now, ergo it's safe to clear it. */
424 arch_clear_pseudo_atomic_interrupted(context);
426 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
427 #ifdef LISP_FEATURE_SB_THREAD
428 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
429 /* STOP_FOR_GC_PENDING and GC_PENDING are cleared by
430 * the signal handler if it actually stops us. */
431 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
434 if (SymbolValue(GC_PENDING,thread) != NIL) {
435 /* GC_PENDING is cleared in SUB-GC, or if another thread
436 * is doing a gc already we will get a SIG_STOP_FOR_GC and
437 * that will clear it. */
440 check_blockables_blocked_or_lose();
443 #ifndef LISP_FEATURE_WIN32
444 /* we may be here only to do the gc stuff, if interrupts are
445 * enabled run the pending handler */
446 if (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) {
447 struct interrupt_data *data = thread->interrupt_data;
449 /* There may be no pending handler, because it was only a gc
450 * that had to be executed or because pseudo atomic triggered
451 * twice for a single interrupt. For the interested reader,
452 * that may happen if an interrupt hits after the interrupted
453 * flag is cleared but before pseudo-atomic is set and a
454 * pseudo atomic is interrupted in that interrupt. */
455 if (data->pending_handler) {
457 /* If we're here as the result of a pseudo-atomic as opposed
458 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
459 * NIL, because maybe_defer_handler sets
460 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
461 SetSymbolValue(INTERRUPT_PENDING, NIL, thread);
463 /* restore the saved signal mask from the original signal (the
464 * one that interrupted us during the critical section) into the
465 * os_context for the signal we're currently in the handler for.
466 * This should ensure that when we return from the handler the
467 * blocked signals are unblocked */
468 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
470 sigemptyset(&data->pending_mask);
471 /* This will break on sparc linux: the deferred handler really wants
472 * to be called with a void_context */
473 run_deferred_handler(data,(void *)context);
480 * the two main signal handlers:
481 * interrupt_handle_now(..)
482 * maybe_now_maybe_later(..)
484 * to which we have added interrupt_handle_now_handler(..). Why?
485 * Well, mostly because the SPARC/Linux platform doesn't quite do
486 * signals the way we want them done. The third argument in the
487 * handler isn't filled in by the kernel properly, so we fix it up
488 * ourselves in the arch_os_get_context(..) function; however, we only
489 * want to do this when we first hit the handler, and not when
490 * interrupt_handle_now(..) is being called from some other handler
491 * (when the fixup will already have been done). -- CSR, 2002-07-23
495 interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
497 #ifdef FOREIGN_FUNCTION_CALL_FLAG
498 boolean were_in_lisp;
500 union interrupt_handler handler;
502 check_blockables_blocked_or_lose();
504 #ifndef LISP_FEATURE_WIN32
505 if (sigismember(&deferrable_sigset,signal))
506 check_interrupts_enabled_or_lose(context);
509 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
510 /* Under Linux on some architectures, we appear to have to restore
511 the FPU control word from the context, as after the signal is
512 delivered we appear to have a null FPU control word. */
513 os_restore_fp_control(context);
516 handler = interrupt_handlers[signal];
518 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
522 #ifdef FOREIGN_FUNCTION_CALL_FLAG
523 were_in_lisp = !foreign_function_call_active;
527 fake_foreign_function_call(context);
530 FSHOW_SIGNAL((stderr,
531 "/entering interrupt_handle_now(%d, info, context)\n",
534 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
536 /* This can happen if someone tries to ignore or default one
537 * of the signals we need for runtime support, and the runtime
538 * support decides to pass on it. */
539 lose("no handler for signal %d in interrupt_handle_now(..)\n", signal);
541 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
542 /* Once we've decided what to do about contexts in a
543 * return-elsewhere world (the original context will no longer
544 * be available; should we copy it or was nobody using it anyway?)
545 * then we should convert this to return-elsewhere */
547 /* CMUCL comment said "Allocate the SAPs while the interrupts
548 * are still disabled.". I (dan, 2003.08.21) assume this is
549 * because we're not in pseudoatomic and allocation shouldn't
550 * be interrupted. In which case it's no longer an issue as
551 * all our allocation from C now goes through a PA wrapper,
552 * but still, doesn't hurt.
554 * Yeah, but non-gencgc platforms don't really wrap allocation
555 * in PA. MG - 2005-08-29 */
557 lispobj info_sap,context_sap = alloc_sap(context);
558 info_sap = alloc_sap(info);
559 /* Leave deferrable signals blocked, the handler itself will
560 * allow signals again when it sees fit. */
561 #ifdef LISP_FEATURE_SB_THREAD
564 sigemptyset(&unblock);
565 sigaddset(&unblock, SIG_STOP_FOR_GC);
566 #ifdef SIG_RESUME_FROM_GC
567 sigaddset(&unblock, SIG_RESUME_FROM_GC);
569 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
573 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
575 funcall3(handler.lisp,
581 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
583 #ifndef LISP_FEATURE_WIN32
584 /* Allow signals again. */
585 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
587 (*handler.c)(signal, info, context);
590 #ifdef FOREIGN_FUNCTION_CALL_FLAG
594 undo_fake_foreign_function_call(context); /* block signals again */
597 FSHOW_SIGNAL((stderr,
598 "/returning from interrupt_handle_now(%d, info, context)\n",
602 /* This is called at the end of a critical section if the indications
603 * are that some signal was deferred during the section. Note that as
604 * far as C or the kernel is concerned we dealt with the signal
605 * already; we're just doing the Lisp-level processing now that we
608 run_deferred_handler(struct interrupt_data *data, void *v_context)
610 /* The pending_handler may enable interrupts and then another
611 * interrupt may hit, overwrite interrupt_data, so reset the
612 * pending handler before calling it. Trust the handler to finish
613 * with the siginfo before enabling interrupts. */
614 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
616 data->pending_handler=0;
617 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
620 #ifndef LISP_FEATURE_WIN32
622 maybe_defer_handler(void *handler, struct interrupt_data *data,
623 int signal, siginfo_t *info, os_context_t *context)
625 struct thread *thread=arch_os_get_current_thread();
627 check_blockables_blocked_or_lose();
629 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
630 lose("interrupt already pending\n");
631 /* If interrupts are disabled then INTERRUPT_PENDING is set and
632 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
633 * atomic section inside a WITHOUT-INTERRUPTS.
635 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
636 store_signal_data_for_later(data,handler,signal,info,context);
637 SetSymbolValue(INTERRUPT_PENDING, T,thread);
638 FSHOW_SIGNAL((stderr,
639 "/maybe_defer_handler(%x,%d),thread=%lu: deferred\n",
640 (unsigned int)handler,signal,
641 (unsigned long)thread->os_thread));
644 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
645 * actually use its argument for anything on x86, so this branch
646 * may succeed even when context is null (gencgc alloc()) */
647 if (arch_pseudo_atomic_atomic(context)) {
648 store_signal_data_for_later(data,handler,signal,info,context);
649 arch_set_pseudo_atomic_interrupted(context);
650 FSHOW_SIGNAL((stderr,
651 "/maybe_defer_handler(%x,%d),thread=%lu: deferred(PA)\n",
652 (unsigned int)handler,signal,
653 (unsigned long)thread->os_thread));
656 FSHOW_SIGNAL((stderr,
657 "/maybe_defer_handler(%x,%d),thread=%lu: not deferred\n",
658 (unsigned int)handler,signal,
659 (unsigned long)thread->os_thread));
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", signal));
681 /* the signal mask in the context (from before we were
682 * interrupted) is copied to be restored when
683 * run_deferred_handler happens. Then the usually-blocked
684 * signals are added to the mask in the context so that we are
685 * running with blocked signals when the handler returns */
686 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
687 sigaddset_deferrable(os_context_sigmask_addr(context));
692 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
694 os_context_t *context = arch_os_get_context(&void_context);
695 struct thread *thread = arch_os_get_current_thread();
696 struct interrupt_data *data = thread->interrupt_data;
698 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
699 os_restore_fp_control(context);
702 if(!maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
703 interrupt_handle_now(signal, info, context);
707 low_level_interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context)
709 /* No FP control fixage needed, caller has done that. */
710 check_blockables_blocked_or_lose();
711 check_interrupts_enabled_or_lose(context);
712 interrupt_low_level_handlers[signal](signal, info, context);
713 /* No Darwin context fixage needed, caller does that. */
717 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
719 os_context_t *context = arch_os_get_context(&void_context);
720 struct thread *thread = arch_os_get_current_thread();
721 struct interrupt_data *data = thread->interrupt_data;
723 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
724 os_restore_fp_control(context);
727 if(!maybe_defer_handler(low_level_interrupt_handle_now,data,
728 signal,info,context))
729 low_level_interrupt_handle_now(signal, info, context);
733 #ifdef LISP_FEATURE_SB_THREAD
736 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
738 os_context_t *context = arch_os_get_context(&void_context);
740 struct thread *thread=arch_os_get_current_thread();
743 if (arch_pseudo_atomic_atomic(context)) {
744 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
745 arch_set_pseudo_atomic_interrupted(context);
746 FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred (PA)\n",
750 else if (SymbolValue(GC_INHIBIT,thread) != NIL) {
751 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
752 FSHOW_SIGNAL((stderr,
753 "thread=%lu sig_stop_for_gc deferred (*GC-INHIBIT*)\n",
758 /* Not PA and GC not inhibited -- we can stop now. */
760 /* need the context stored so it can have registers scavenged */
761 fake_foreign_function_call(context);
763 /* Block everything. */
765 thread_sigmask(SIG_BLOCK,&ss,0);
767 /* Not pending anymore. */
768 SetSymbolValue(GC_PENDING,NIL,thread);
769 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
771 if(thread->state!=STATE_RUNNING) {
772 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
773 fixnum_value(thread->state));
776 thread->state=STATE_SUSPENDED;
777 FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread));
780 #if defined(SIG_RESUME_FROM_GC)
781 sigaddset(&ss,SIG_RESUME_FROM_GC);
783 sigaddset(&ss,SIG_STOP_FOR_GC);
786 /* It is possible to get SIGCONT (and probably other non-blockable
788 #ifdef SIG_RESUME_FROM_GC
791 do { sigwait(&ss, &sigret); }
792 while (sigret != SIG_RESUME_FROM_GC);
795 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
798 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
799 if(thread->state!=STATE_RUNNING) {
800 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
801 fixnum_value(thread->state));
804 undo_fake_foreign_function_call(context);
809 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
811 os_context_t *context = arch_os_get_context(&void_context);
812 #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT)
813 os_restore_fp_control(context);
815 interrupt_handle_now(signal, info, context);
818 /* manipulate the signal context and stack such that when the handler
819 * returns, it will call function instead of whatever it was doing
823 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
824 extern int *context_eflags_addr(os_context_t *context);
827 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
828 extern void post_signal_tramp(void);
829 extern void call_into_lisp_tramp(void);
831 arrange_return_to_lisp_function(os_context_t *context, lispobj function)
833 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
834 void * fun=native_pointer(function);
835 void *code = &(((struct simple_fun *) fun)->code);
838 /* Build a stack frame showing `interrupted' so that the
839 * user's backtrace makes (as much) sense (as usual) */
841 /* FIXME: what about restoring fp state? */
842 /* FIXME: what about restoring errno? */
843 #ifdef LISP_FEATURE_X86
844 /* Suppose the existence of some function that saved all
845 * registers, called call_into_lisp, then restored GP registers and
846 * returned. It would look something like this:
854 pushl {address of function to call}
855 call 0x8058db0 <call_into_lisp>
862 * What we do here is set up the stack that call_into_lisp would
863 * expect to see if it had been called by this code, and frob the
864 * signal context so that signal return goes directly to call_into_lisp,
865 * and when that function (and the lisp function it invoked) returns,
866 * it returns to the second half of this imaginary function which
867 * restores all registers and returns to C
869 * For this to work, the latter part of the imaginary function
870 * must obviously exist in reality. That would be post_signal_tramp
873 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
875 #if defined(LISP_FEATURE_DARWIN)
876 u32 *register_save_area = (u32 *)os_validate(0, 0x40);
878 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp));
879 FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context));
881 /* 1. os_validate (malloc/mmap) register_save_block
882 * 2. copy register state into register_save_block
883 * 3. put a pointer to register_save_block in a register in the context
884 * 4. set the context's EIP to point to a trampoline which:
885 * a. builds the fake stack frame from the block
887 * c. calls the function
890 *register_save_area = *os_context_pc_addr(context);
891 *(register_save_area + 1) = function;
892 *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI);
893 *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI);
894 *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX);
895 *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX);
896 *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX);
897 *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX);
898 *(register_save_area + 8) = *context_eflags_addr(context);
900 *os_context_pc_addr(context) =
901 (os_context_register_t) call_into_lisp_tramp;
902 *os_context_register_addr(context,reg_ECX) =
903 (os_context_register_t) register_save_area;
906 /* return address for call_into_lisp: */
907 *(sp-15) = (u32)post_signal_tramp;
908 *(sp-14) = function; /* args for call_into_lisp : function*/
909 *(sp-13) = 0; /* arg array */
910 *(sp-12) = 0; /* no. args */
911 /* this order matches that used in POPAD */
912 *(sp-11)=*os_context_register_addr(context,reg_EDI);
913 *(sp-10)=*os_context_register_addr(context,reg_ESI);
915 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
916 /* POPAD ignores the value of ESP: */
918 *(sp-7)=*os_context_register_addr(context,reg_EBX);
920 *(sp-6)=*os_context_register_addr(context,reg_EDX);
921 *(sp-5)=*os_context_register_addr(context,reg_ECX);
922 *(sp-4)=*os_context_register_addr(context,reg_EAX);
923 *(sp-3)=*context_eflags_addr(context);
924 *(sp-2)=*os_context_register_addr(context,reg_EBP);
925 *(sp-1)=*os_context_pc_addr(context);
929 #elif defined(LISP_FEATURE_X86_64)
930 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
932 /* return address for call_into_lisp: */
933 *(sp-18) = (u64)post_signal_tramp;
935 *(sp-17)=*os_context_register_addr(context,reg_R15);
936 *(sp-16)=*os_context_register_addr(context,reg_R14);
937 *(sp-15)=*os_context_register_addr(context,reg_R13);
938 *(sp-14)=*os_context_register_addr(context,reg_R12);
939 *(sp-13)=*os_context_register_addr(context,reg_R11);
940 *(sp-12)=*os_context_register_addr(context,reg_R10);
941 *(sp-11)=*os_context_register_addr(context,reg_R9);
942 *(sp-10)=*os_context_register_addr(context,reg_R8);
943 *(sp-9)=*os_context_register_addr(context,reg_RDI);
944 *(sp-8)=*os_context_register_addr(context,reg_RSI);
945 /* skip RBP and RSP */
946 *(sp-7)=*os_context_register_addr(context,reg_RBX);
947 *(sp-6)=*os_context_register_addr(context,reg_RDX);
948 *(sp-5)=*os_context_register_addr(context,reg_RCX);
949 *(sp-4)=*os_context_register_addr(context,reg_RAX);
950 *(sp-3)=*context_eflags_addr(context);
951 *(sp-2)=*os_context_register_addr(context,reg_RBP);
952 *(sp-1)=*os_context_pc_addr(context);
954 *os_context_register_addr(context,reg_RDI) =
955 (os_context_register_t)function; /* function */
956 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
957 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
959 struct thread *th=arch_os_get_current_thread();
960 build_fake_control_stack_frames(th,context);
963 #ifdef LISP_FEATURE_X86
965 #if !defined(LISP_FEATURE_DARWIN)
966 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
967 *os_context_register_addr(context,reg_ECX) = 0;
968 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
970 *os_context_register_addr(context,reg_UESP) =
971 (os_context_register_t)(sp-15);
973 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
974 #endif /* __NETBSD__ */
975 #endif /* LISP_FEATURE_DARWIN */
977 #elif defined(LISP_FEATURE_X86_64)
978 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
979 *os_context_register_addr(context,reg_RCX) = 0;
980 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
981 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
983 /* this much of the calling convention is common to all
985 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
986 *os_context_register_addr(context,reg_NARGS) = 0;
987 *os_context_register_addr(context,reg_LIP) =
988 (os_context_register_t)(unsigned long)code;
989 *os_context_register_addr(context,reg_CFP) =
990 (os_context_register_t)(unsigned long)current_control_frame_pointer;
992 #ifdef ARCH_HAS_NPC_REGISTER
993 *os_context_npc_addr(context) =
994 4 + *os_context_pc_addr(context);
996 #ifdef LISP_FEATURE_SPARC
997 *os_context_register_addr(context,reg_CODE) =
998 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
1002 #ifdef LISP_FEATURE_SB_THREAD
1004 /* FIXME: this function can go away when all lisp handlers are invoked
1005 * via arrange_return_to_lisp_function. */
1007 interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
1009 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
1011 /* let the handler enable interrupts again when it sees fit */
1012 sigaddset_deferrable(os_context_sigmask_addr(context));
1013 arrange_return_to_lisp_function(context, StaticSymbolFunction(RUN_INTERRUPTION));
1018 /* KLUDGE: Theoretically the approach we use for undefined alien
1019 * variables should work for functions as well, but on PPC/Darwin
1020 * we get bus error at bogus addresses instead, hence this workaround,
1021 * that has the added benefit of automatically discriminating between
1022 * functions and variables.
1025 undefined_alien_function(void)
1027 funcall0(StaticSymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
1031 handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
1033 struct thread *th=arch_os_get_current_thread();
1035 /* note the os_context hackery here. When the signal handler returns,
1036 * it won't go back to what it was doing ... */
1037 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
1038 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
1039 /* We hit the end of the control stack: disable guard page
1040 * protection so the error handler has some headroom, protect the
1041 * previous page so that we can catch returns from the guard page
1042 * and restore it. */
1043 protect_control_stack_guard_page(0);
1044 protect_control_stack_return_guard_page(1);
1046 arrange_return_to_lisp_function
1047 (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
1050 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
1051 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
1052 /* We're returning from the guard page: reprotect it, and
1053 * unprotect this one. This works even if we somehow missed
1054 * the return-guard-page, and hit it on our way to new
1055 * exhaustion instead. */
1056 protect_control_stack_guard_page(1);
1057 protect_control_stack_return_guard_page(0);
1060 else if (addr >= undefined_alien_address &&
1061 addr < undefined_alien_address + os_vm_page_size) {
1062 arrange_return_to_lisp_function
1063 (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
1070 * noise to install handlers
1073 #ifndef LISP_FEATURE_WIN32
1074 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1075 * they are blocked, in Linux 2.6 the default handler is invoked
1076 * instead that usually coredumps. One might hastily think that adding
1077 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1078 * the whole sa_mask is ignored and instead of not adding the signal
1079 * in question to the mask. That means if it's not blockable the
1080 * signal must be unblocked at the beginning of signal handlers.
1082 * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different
1083 * way: if SA_NODEFER is set and the signal is in sa_mask, the signal
1084 * will be unblocked in the sigmask during the signal handler. -- RMK
1087 static volatile int sigaction_nodefer_works = -1;
1089 #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT
1090 #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1
1093 sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context)
1095 sigset_t empty, current;
1097 sigemptyset(&empty);
1098 thread_sigmask(SIG_BLOCK, &empty, ¤t);
1099 /* There should be exactly two blocked signals: the two we added
1100 * to sa_mask when setting up the handler. NetBSD doesn't block
1101 * the signal we're handling when SA_NODEFER is set; Linux before
1102 * 2.6.13 or so also doesn't block the other signal when
1103 * SA_NODEFER is set. */
1104 for(i = 1; i < NSIG; i++)
1105 if (sigismember(¤t, i) !=
1106 (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) {
1107 FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i));
1108 sigaction_nodefer_works = 0;
1110 if (sigaction_nodefer_works == -1)
1111 sigaction_nodefer_works = 1;
1115 see_if_sigaction_nodefer_works(void)
1117 struct sigaction sa, old_sa;
1119 sa.sa_flags = SA_SIGINFO | SA_NODEFER;
1120 sa.sa_sigaction = sigaction_nodefer_test_handler;
1121 sigemptyset(&sa.sa_mask);
1122 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL);
1123 sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL);
1124 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa);
1125 /* Make sure no signals are blocked. */
1128 sigemptyset(&empty);
1129 thread_sigmask(SIG_SETMASK, &empty, 0);
1131 kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL);
1132 while (sigaction_nodefer_works == -1);
1133 sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL);
1136 #undef SA_NODEFER_TEST_BLOCK_SIGNAL
1137 #undef SA_NODEFER_TEST_KILL_SIGNAL
1140 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1144 sigemptyset(&unblock);
1145 sigaddset(&unblock, signal);
1146 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1147 interrupt_handle_now_handler(signal, info, void_context);
1151 low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1155 sigemptyset(&unblock);
1156 sigaddset(&unblock, signal);
1157 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1158 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1162 undoably_install_low_level_interrupt_handler (int signal,
1163 interrupt_handler_t handler)
1165 struct sigaction sa;
1167 if (0 > signal || signal >= NSIG) {
1168 lose("bad signal number %d\n", signal);
1171 if (ARE_SAME_HANDLER(handler, SIG_DFL))
1172 sa.sa_sigaction = handler;
1173 else if (sigismember(&deferrable_sigset,signal))
1174 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1175 /* The use of a trampoline appears to break the
1176 arch_os_get_context() workaround for SPARC/Linux. For now,
1177 don't use the trampoline (and so be vulnerable to the problems
1178 that SA_NODEFER is meant to solve. */
1179 #if !(defined(LISP_FEATURE_SPARC) && defined(LISP_FEATURE_LINUX))
1180 else if (!sigaction_nodefer_works &&
1181 !sigismember(&blockable_sigset, signal))
1182 sa.sa_sigaction = low_level_unblock_me_trampoline;
1185 sa.sa_sigaction = handler;
1187 sigcopyset(&sa.sa_mask, &blockable_sigset);
1188 sa.sa_flags = SA_SIGINFO | SA_RESTART
1189 | (sigaction_nodefer_works ? SA_NODEFER : 0);
1190 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1191 if((signal==SIG_MEMORY_FAULT)
1192 #ifdef SIG_INTERRUPT_THREAD
1193 || (signal==SIG_INTERRUPT_THREAD)
1196 sa.sa_flags |= SA_ONSTACK;
1199 sigaction(signal, &sa, NULL);
1200 interrupt_low_level_handlers[signal] =
1201 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1205 /* This is called from Lisp. */
1207 install_handler(int signal, void handler(int, siginfo_t*, void*))
1209 #ifndef LISP_FEATURE_WIN32
1210 struct sigaction sa;
1212 union interrupt_handler oldhandler;
1214 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1217 sigaddset(&new, signal);
1218 thread_sigmask(SIG_BLOCK, &new, &old);
1220 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1221 (unsigned int)interrupt_low_level_handlers[signal]));
1222 if (interrupt_low_level_handlers[signal]==0) {
1223 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1224 ARE_SAME_HANDLER(handler, SIG_IGN))
1225 sa.sa_sigaction = handler;
1226 else if (sigismember(&deferrable_sigset, signal))
1227 sa.sa_sigaction = maybe_now_maybe_later;
1228 else if (!sigaction_nodefer_works &&
1229 !sigismember(&blockable_sigset, signal))
1230 sa.sa_sigaction = unblock_me_trampoline;
1232 sa.sa_sigaction = interrupt_handle_now_handler;
1234 sigcopyset(&sa.sa_mask, &blockable_sigset);
1235 sa.sa_flags = SA_SIGINFO | SA_RESTART |
1236 (sigaction_nodefer_works ? SA_NODEFER : 0);
1237 sigaction(signal, &sa, NULL);
1240 oldhandler = interrupt_handlers[signal];
1241 interrupt_handlers[signal].c = handler;
1243 thread_sigmask(SIG_SETMASK, &old, 0);
1245 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1247 return (unsigned long)oldhandler.lisp;
1249 /* Probably-wrong Win32 hack */
1255 interrupt_init(void)
1257 #ifndef LISP_FEATURE_WIN32
1259 SHOW("entering interrupt_init()");
1260 see_if_sigaction_nodefer_works();
1261 sigemptyset(&deferrable_sigset);
1262 sigemptyset(&blockable_sigset);
1263 sigaddset_deferrable(&deferrable_sigset);
1264 sigaddset_blockable(&blockable_sigset);
1266 /* Set up high level handler information. */
1267 for (i = 0; i < NSIG; i++) {
1268 interrupt_handlers[i].c =
1269 /* (The cast here blasts away the distinction between
1270 * SA_SIGACTION-style three-argument handlers and
1271 * signal(..)-style one-argument handlers, which is OK
1272 * because it works to call the 1-argument form where the
1273 * 3-argument form is expected.) */
1274 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1277 SHOW("returning from interrupt_init()");
1281 #ifndef LISP_FEATURE_WIN32
1283 siginfo_code(siginfo_t *info)
1285 return info->si_code;
1287 os_vm_address_t current_memory_fault_address;
1290 lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr)
1292 /* FIXME: This is lossy: if we get another memory fault (eg. from
1293 * another thread) before lisp has read this, we lose the information.
1294 * However, since this is mostly informative, we'll live with that for
1295 * now -- some address is better then no address in this case.
1297 current_memory_fault_address = addr;
1298 arrange_return_to_lisp_function(context, StaticSymbolFunction(MEMORY_FAULT_ERROR));
1303 unhandled_trap_error(os_context_t *context)
1305 lispobj context_sap;
1306 fake_foreign_function_call(context);
1307 context_sap = alloc_sap(context);
1308 #ifndef LISP_FEATURE_WIN32
1309 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1311 funcall1(StaticSymbolFunction(UNHANDLED_TRAP_ERROR), context_sap);
1312 lose("UNHANDLED-TRAP-ERROR fell through");
1315 /* Common logic for trapping instructions. How we actually handle each
1316 * case is highly architecture dependent, but the overall shape is
1319 handle_trap(os_context_t *context, int trap)
1322 case trap_PendingInterrupt:
1323 FSHOW((stderr, "/<trap pending interrupt>\n"));
1324 arch_skip_instruction(context);
1325 interrupt_handle_pending(context);
1329 FSHOW((stderr, "/<trap error/cerror %d>\n", trap));
1330 interrupt_internal_error(context, trap==trap_Cerror);
1332 case trap_Breakpoint:
1333 arch_handle_breakpoint(context);
1335 case trap_FunEndBreakpoint:
1336 arch_handle_fun_end_breakpoint(context);
1338 #ifdef trap_AfterBreakpoint
1339 case trap_AfterBreakpoint:
1340 arch_handle_after_breakpoint(context);
1343 #ifdef trap_SingleStepAround
1344 case trap_SingleStepAround:
1345 case trap_SingleStepBefore:
1346 arch_handle_single_step_trap(context, trap);
1350 fake_foreign_function_call(context);
1351 lose("%%PRIMITIVE HALT called; the party is over.\n");
1353 unhandled_trap_error(context);