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 */
48 #include <sys/types.h>
56 #include "interrupt.h"
65 #include "genesis/fdefn.h"
66 #include "genesis/simple-fun.h"
67 #include "genesis/cons.h"
71 void run_deferred_handler(struct interrupt_data *data, void *v_context);
72 static void store_signal_data_for_later (struct interrupt_data *data,
73 void *handler, int signal,
75 os_context_t *context);
76 boolean interrupt_maybe_gc_int(int signal, siginfo_t *info, void *v_context);
78 void 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 sigaddset(s, SIGXCPU);
90 sigaddset(s, SIGXFSZ);
91 sigaddset(s, SIGVTALRM);
92 sigaddset(s, SIGPROF);
93 sigaddset(s, SIGWINCH);
94 sigaddset(s, SIGUSR1);
95 sigaddset(s, SIGUSR2);
96 #ifdef LISP_FEATURE_SB_THREAD
97 sigaddset(s, SIG_INTERRUPT_THREAD);
101 void sigaddset_blockable(sigset_t *s)
103 sigaddset_deferrable(s);
104 #ifdef LISP_FEATURE_SB_THREAD
105 sigaddset(s, SIG_STOP_FOR_GC);
109 /* initialized in interrupt_init */
110 static sigset_t deferrable_sigset;
111 static sigset_t blockable_sigset;
114 check_blockables_blocked_or_lose()
116 /* Get the current sigmask, by blocking the empty set. */
117 sigset_t empty,current;
120 thread_sigmask(SIG_BLOCK, &empty, ¤t);
121 for(i=0;i<NSIG;i++) {
122 if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i))
123 lose("blockable signal %d not blocked",i);
127 inline static void check_interrupts_enabled_or_lose(os_context_t *context)
129 struct thread *thread=arch_os_get_current_thread();
130 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
131 lose("interrupts not enabled");
133 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
134 (!foreign_function_call_active) &&
136 arch_pseudo_atomic_atomic(context))
137 lose ("in pseudo atomic section");
140 /* When we catch an internal error, should we pass it back to Lisp to
141 * be handled in a high-level way? (Early in cold init, the answer is
142 * 'no', because Lisp is still too brain-dead to handle anything.
143 * After sufficient initialization has been completed, the answer
145 boolean internal_errors_enabled = 0;
147 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*);
148 union interrupt_handler interrupt_handlers[NSIG];
150 /* At the toplevel repl we routinely call this function. The signal
151 * mask ought to be clear anyway most of the time, but may be non-zero
152 * if we were interrupted e.g. while waiting for a queue. */
154 void reset_signal_mask(void)
158 thread_sigmask(SIG_SETMASK,&new,0);
161 void block_blockable_signals(void)
164 sigcopyset(&block, &blockable_sigset);
165 thread_sigmask(SIG_BLOCK, &block, 0);
170 * utility routines used by various signal handlers
174 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
176 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
180 /* Build a fake stack frame or frames */
182 current_control_frame_pointer =
183 (lispobj *)(unsigned long)
184 (*os_context_register_addr(context, reg_CSP));
185 if ((lispobj *)(unsigned long)
186 (*os_context_register_addr(context, reg_CFP))
187 == current_control_frame_pointer) {
188 /* There is a small window during call where the callee's
189 * frame isn't built yet. */
190 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
191 == FUN_POINTER_LOWTAG) {
192 /* We have called, but not built the new frame, so
193 * build it for them. */
194 current_control_frame_pointer[0] =
195 *os_context_register_addr(context, reg_OCFP);
196 current_control_frame_pointer[1] =
197 *os_context_register_addr(context, reg_LRA);
198 current_control_frame_pointer += 8;
199 /* Build our frame on top of it. */
200 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
203 /* We haven't yet called, build our frame as if the
204 * partial frame wasn't there. */
205 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
208 /* We can't tell whether we are still in the caller if it had to
209 * allocate a stack frame due to stack arguments. */
210 /* This observation provoked some past CMUCL maintainer to ask
211 * "Can anything strange happen during return?" */
214 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
217 current_control_stack_pointer = current_control_frame_pointer + 8;
219 current_control_frame_pointer[0] = oldcont;
220 current_control_frame_pointer[1] = NIL;
221 current_control_frame_pointer[2] =
222 (lispobj)(*os_context_register_addr(context, reg_CODE));
227 fake_foreign_function_call(os_context_t *context)
230 struct thread *thread=arch_os_get_current_thread();
232 /* context_index incrementing must not be interrupted */
233 check_blockables_blocked_or_lose();
235 /* Get current Lisp state from context. */
237 dynamic_space_free_pointer =
238 (lispobj *)(unsigned long)
239 (*os_context_register_addr(context, reg_ALLOC));
240 #if defined(LISP_FEATURE_ALPHA)
241 if ((long)dynamic_space_free_pointer & 1) {
242 lose("dead in fake_foreign_function_call, context = %x", context);
247 current_binding_stack_pointer =
248 (lispobj *)(unsigned long)
249 (*os_context_register_addr(context, reg_BSP));
252 build_fake_control_stack_frames(thread,context);
254 /* Do dynamic binding of the active interrupt context index
255 * and save the context in the context array. */
257 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
259 if (context_index >= MAX_INTERRUPTS) {
260 lose("maximum interrupt nesting depth (%d) exceeded", MAX_INTERRUPTS);
263 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
264 make_fixnum(context_index + 1),thread);
266 thread->interrupt_contexts[context_index] = context;
268 /* no longer in Lisp now */
269 foreign_function_call_active = 1;
272 /* blocks all blockable signals. If you are calling from a signal handler,
273 * the usual signal mask will be restored from the context when the handler
274 * finishes. Otherwise, be careful */
277 undo_fake_foreign_function_call(os_context_t *context)
279 struct thread *thread=arch_os_get_current_thread();
280 /* Block all blockable signals. */
281 block_blockable_signals();
283 /* going back into Lisp */
284 foreign_function_call_active = 0;
286 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
290 /* Put the dynamic space free pointer back into the context. */
291 *os_context_register_addr(context, reg_ALLOC) =
292 (unsigned long) dynamic_space_free_pointer;
296 /* a handler for the signal caused by execution of a trap opcode
297 * signalling an internal error */
299 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
304 fake_foreign_function_call(context);
306 if (!internal_errors_enabled) {
307 describe_internal_error(context);
308 /* There's no good way to recover from an internal error
309 * before the Lisp error handling mechanism is set up. */
310 lose("internal error too early in init, can't recover");
313 /* Allocate the SAP object while the interrupts are still
315 context_sap = alloc_sap(context);
317 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
319 SHOW("in interrupt_internal_error");
321 /* Display some rudimentary debugging information about the
322 * error, so that even if the Lisp error handler gets badly
323 * confused, we have a chance to determine what's going on. */
324 describe_internal_error(context);
326 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
327 continuable ? T : NIL);
329 undo_fake_foreign_function_call(context); /* blocks signals again */
331 arch_skip_instruction(context);
335 interrupt_handle_pending(os_context_t *context)
337 struct thread *thread;
338 struct interrupt_data *data;
340 check_blockables_blocked_or_lose();
342 thread=arch_os_get_current_thread();
343 data=thread->interrupt_data;
345 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
346 #ifdef LISP_FEATURE_SB_THREAD
347 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
348 /* another thread has already initiated a gc, this attempt
349 * might as well be cancelled */
350 SetSymbolValue(GC_PENDING,NIL,thread);
351 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
352 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
355 if (SymbolValue(GC_PENDING,thread) != NIL) {
356 /* GC_PENDING is cleared in SUB-GC, or if another thread
357 * is doing a gc already we will get a SIG_STOP_FOR_GC and
358 * that will clear it. */
359 interrupt_maybe_gc_int(0,NULL,context);
361 check_blockables_blocked_or_lose();
364 /* we may be here only to do the gc stuff, if interrupts are
365 * enabled run the pending handler */
366 if (!((SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) ||
368 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
369 (!foreign_function_call_active) &&
371 arch_pseudo_atomic_atomic(context)))) {
373 /* There may be no pending handler, because it was only a gc
374 * that had to be executed or because pseudo atomic triggered
375 * twice for a single interrupt. For the interested reader,
376 * that may happen if an interrupt hits after the interrupted
377 * flag is cleared but before pseduo-atomic is set and a
378 * pseudo atomic is interrupted in that interrupt. */
379 if (data->pending_handler) {
381 /* If we're here as the result of a pseudo-atomic as opposed
382 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
383 * NIL, because maybe_defer_handler sets
384 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
385 SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
387 /* restore the saved signal mask from the original signal (the
388 * one that interrupted us during the critical section) into the
389 * os_context for the signal we're currently in the handler for.
390 * This should ensure that when we return from the handler the
391 * blocked signals are unblocked */
392 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
394 sigemptyset(&data->pending_mask);
395 /* This will break on sparc linux: the deferred handler really wants
396 * to be called with a void_context */
397 run_deferred_handler(data,(void *)context);
403 * the two main signal handlers:
404 * interrupt_handle_now(..)
405 * maybe_now_maybe_later(..)
407 * to which we have added interrupt_handle_now_handler(..). Why?
408 * Well, mostly because the SPARC/Linux platform doesn't quite do
409 * signals the way we want them done. The third argument in the
410 * handler isn't filled in by the kernel properly, so we fix it up
411 * ourselves in the arch_os_get_context(..) function; however, we only
412 * want to do this when we first hit the handler, and not when
413 * interrupt_handle_now(..) is being called from some other handler
414 * (when the fixup will already have been done). -- CSR, 2002-07-23
418 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
420 os_context_t *context = (os_context_t*)void_context;
421 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
422 boolean were_in_lisp;
424 union interrupt_handler handler;
425 check_blockables_blocked_or_lose();
426 if (sigismember(&deferrable_sigset,signal))
427 check_interrupts_enabled_or_lose(context);
429 #ifdef LISP_FEATURE_LINUX
430 /* Under Linux on some architectures, we appear to have to restore
431 the FPU control word from the context, as after the signal is
432 delivered we appear to have a null FPU control word. */
433 os_restore_fp_control(context);
435 handler = interrupt_handlers[signal];
437 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
441 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
442 were_in_lisp = !foreign_function_call_active;
446 fake_foreign_function_call(context);
449 FSHOW_SIGNAL((stderr,
450 "/entering interrupt_handle_now(%d, info, context)\n",
453 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
455 /* This can happen if someone tries to ignore or default one
456 * of the signals we need for runtime support, and the runtime
457 * support decides to pass on it. */
458 lose("no handler for signal %d in interrupt_handle_now(..)", signal);
460 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
461 /* Once we've decided what to do about contexts in a
462 * return-elsewhere world (the original context will no longer
463 * be available; should we copy it or was nobody using it anyway?)
464 * then we should convert this to return-elsewhere */
466 /* CMUCL comment said "Allocate the SAPs while the interrupts
467 * are still disabled.". I (dan, 2003.08.21) assume this is
468 * because we're not in pseudoatomic and allocation shouldn't
469 * be interrupted. In which case it's no longer an issue as
470 * all our allocation from C now goes through a PA wrapper,
471 * but still, doesn't hurt.
473 * Yeah, but non-gencgc platforms that don't really wrap
474 * allocation in PA. MG - 2005-08-29 */
476 lispobj info_sap,context_sap = alloc_sap(context);
477 info_sap = alloc_sap(info);
478 /* Leave deferrable signals blocked, the handler itself will
479 * allow signals again when it sees fit. */
480 #ifdef LISP_FEATURE_SB_THREAD
483 sigaddset(&unblock, SIG_STOP_FOR_GC);
484 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
488 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
490 funcall3(handler.lisp,
496 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
498 /* Allow signals again. */
499 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
501 (*handler.c)(signal, info, void_context);
504 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
508 undo_fake_foreign_function_call(context); /* block signals again */
511 FSHOW_SIGNAL((stderr,
512 "/returning from interrupt_handle_now(%d, info, context)\n",
516 /* This is called at the end of a critical section if the indications
517 * are that some signal was deferred during the section. Note that as
518 * far as C or the kernel is concerned we dealt with the signal
519 * already; we're just doing the Lisp-level processing now that we
523 run_deferred_handler(struct interrupt_data *data, void *v_context) {
524 /* The pending_handler may enable interrupts and then another
525 * interrupt may hit, overwrite interrupt_data, so reset the
526 * pending handler before calling it. Trust the handler to finish
527 * with the siginfo before enabling interrupts. */
528 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
529 data->pending_handler=0;
530 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
534 maybe_defer_handler(void *handler, struct interrupt_data *data,
535 int signal, siginfo_t *info, os_context_t *context)
537 struct thread *thread=arch_os_get_current_thread();
539 check_blockables_blocked_or_lose();
541 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
542 lose("interrupt already pending");
543 /* If interrupts are disabled then INTERRUPT_PENDING is set and
544 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
545 * atomic section inside a WITHOUT-INTERRUPTS.
547 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
548 store_signal_data_for_later(data,handler,signal,info,context);
549 SetSymbolValue(INTERRUPT_PENDING, T,thread);
550 FSHOW_SIGNAL((stderr,
551 "/maybe_defer_handler(%x,%d),thread=%lu: deferred\n",
552 (unsigned int)handler,signal,
553 (unsigned long)thread->os_thread));
556 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
557 * actually use its argument for anything on x86, so this branch
558 * may succeed even when context is null (gencgc alloc()) */
560 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
561 /* FIXME: this foreign_function_call_active test is dubious at
562 * best. If a foreign call is made in a pseudo atomic section
563 * (?) or more likely a pseudo atomic section is in a foreign
564 * call then an interrupt is executed immediately. Maybe it
565 * has to do with C code not maintaining pseudo atomic
566 * properly. MG - 2005-08-10 */
567 (!foreign_function_call_active) &&
569 arch_pseudo_atomic_atomic(context)) {
570 store_signal_data_for_later(data,handler,signal,info,context);
571 arch_set_pseudo_atomic_interrupted(context);
572 FSHOW_SIGNAL((stderr,
573 "/maybe_defer_handler(%x,%d),thread=%lu: deferred(PA)\n",
574 (unsigned int)handler,signal,
575 (unsigned long)thread->os_thread));
578 FSHOW_SIGNAL((stderr,
579 "/maybe_defer_handler(%x,%d),thread=%lu: not deferred\n",
580 (unsigned int)handler,signal,
581 (unsigned long)thread->os_thread));
586 store_signal_data_for_later (struct interrupt_data *data, void *handler,
588 siginfo_t *info, os_context_t *context)
590 if (data->pending_handler)
591 lose("tried to overwrite pending interrupt handler %x with %x\n",
592 data->pending_handler, handler);
594 lose("tried to defer null interrupt handler\n");
595 data->pending_handler = handler;
596 data->pending_signal = signal;
598 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
600 /* the signal mask in the context (from before we were
601 * interrupted) is copied to be restored when
602 * run_deferred_handler happens. Then the usually-blocked
603 * signals are added to the mask in the context so that we are
604 * running with blocked signals when the handler returns */
605 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
606 sigaddset_deferrable(os_context_sigmask_addr(context));
611 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
613 os_context_t *context = arch_os_get_context(&void_context);
614 struct thread *thread=arch_os_get_current_thread();
615 struct interrupt_data *data=thread->interrupt_data;
616 #ifdef LISP_FEATURE_LINUX
617 os_restore_fp_control(context);
619 if(maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
621 interrupt_handle_now(signal, info, context);
622 #ifdef LISP_FEATURE_DARWIN
623 /* Work around G5 bug */
624 DARWIN_FIX_CONTEXT(context);
629 low_level_interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
631 os_context_t *context = (os_context_t*)void_context;
633 #ifdef LISP_FEATURE_LINUX
634 os_restore_fp_control(context);
636 check_blockables_blocked_or_lose();
637 check_interrupts_enabled_or_lose(context);
638 interrupt_low_level_handlers[signal](signal, info, void_context);
639 #ifdef LISP_FEATURE_DARWIN
640 /* Work around G5 bug */
641 DARWIN_FIX_CONTEXT(context);
646 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
648 os_context_t *context = arch_os_get_context(&void_context);
649 struct thread *thread=arch_os_get_current_thread();
650 struct interrupt_data *data=thread->interrupt_data;
651 #ifdef LISP_FEATURE_LINUX
652 os_restore_fp_control(context);
654 if(maybe_defer_handler(low_level_interrupt_handle_now,data,
655 signal,info,context))
657 low_level_interrupt_handle_now(signal, info, context);
658 #ifdef LISP_FEATURE_DARWIN
659 /* Work around G5 bug */
660 DARWIN_FIX_CONTEXT(context);
664 #ifdef LISP_FEATURE_SB_THREAD
667 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
669 os_context_t *context = arch_os_get_context(&void_context);
670 struct thread *thread=arch_os_get_current_thread();
673 if ((arch_pseudo_atomic_atomic(context) ||
674 SymbolValue(GC_INHIBIT,thread) != NIL)) {
675 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
676 if (SymbolValue(GC_INHIBIT,thread) == NIL)
677 arch_set_pseudo_atomic_interrupted(context);
678 FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred\n",
681 /* need the context stored so it can have registers scavenged */
682 fake_foreign_function_call(context);
684 sigfillset(&ss); /* Block everything. */
685 thread_sigmask(SIG_BLOCK,&ss,0);
687 /* The GC can't tell if a thread is a zombie, so this would be a
688 * good time to let the kernel reap any of our children in that
689 * awful state, to stop them from being waited for indefinitely.
690 * Userland reaping is done later when GC is finished */
691 if(thread->state!=STATE_RUNNING) {
692 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
693 fixnum_value(thread->state));
695 thread->state=STATE_SUSPENDED;
696 FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread));
698 sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
699 /* It is possible to get SIGCONT (and probably other
700 * non-blockable signals) here. */
701 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
702 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
703 if(thread->state!=STATE_RUNNING) {
704 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
705 fixnum_value(thread->state));
708 undo_fake_foreign_function_call(context);
714 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
716 os_context_t *context = arch_os_get_context(&void_context);
717 interrupt_handle_now(signal, info, context);
718 #ifdef LISP_FEATURE_DARWIN
719 DARWIN_FIX_CONTEXT(context);
724 * stuff to detect and handle hitting the GC trigger
727 #ifndef LISP_FEATURE_GENCGC
728 /* since GENCGC has its own way to record trigger */
730 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
732 if (current_auto_gc_trigger == NULL)
735 void *badaddr=arch_get_bad_addr(signal,info,context);
736 return (badaddr >= (void *)current_auto_gc_trigger &&
737 badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE));
742 /* manipulate the signal context and stack such that when the handler
743 * returns, it will call function instead of whatever it was doing
747 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
748 int *context_eflags_addr(os_context_t *context);
751 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
752 extern void post_signal_tramp(void);
753 void arrange_return_to_lisp_function(os_context_t *context, lispobj function)
755 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
756 void * fun=native_pointer(function);
757 void *code = &(((struct simple_fun *) fun)->code);
760 /* Build a stack frame showing `interrupted' so that the
761 * user's backtrace makes (as much) sense (as usual) */
763 /* FIXME: what about restoring fp state? */
764 /* FIXME: what about restoring errno? */
765 #ifdef LISP_FEATURE_X86
766 /* Suppose the existence of some function that saved all
767 * registers, called call_into_lisp, then restored GP registers and
768 * returned. It would look something like this:
776 pushl {address of function to call}
777 call 0x8058db0 <call_into_lisp>
784 * What we do here is set up the stack that call_into_lisp would
785 * expect to see if it had been called by this code, and frob the
786 * signal context so that signal return goes directly to call_into_lisp,
787 * and when that function (and the lisp function it invoked) returns,
788 * it returns to the second half of this imaginary function which
789 * restores all registers and returns to C
791 * For this to work, the latter part of the imaginary function
792 * must obviously exist in reality. That would be post_signal_tramp
795 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
797 /* return address for call_into_lisp: */
798 *(sp-15) = (u32)post_signal_tramp;
799 *(sp-14) = function; /* args for call_into_lisp : function*/
800 *(sp-13) = 0; /* arg array */
801 *(sp-12) = 0; /* no. args */
802 /* this order matches that used in POPAD */
803 *(sp-11)=*os_context_register_addr(context,reg_EDI);
804 *(sp-10)=*os_context_register_addr(context,reg_ESI);
806 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
807 /* POPAD ignores the value of ESP: */
809 *(sp-7)=*os_context_register_addr(context,reg_EBX);
811 *(sp-6)=*os_context_register_addr(context,reg_EDX);
812 *(sp-5)=*os_context_register_addr(context,reg_ECX);
813 *(sp-4)=*os_context_register_addr(context,reg_EAX);
814 *(sp-3)=*context_eflags_addr(context);
815 *(sp-2)=*os_context_register_addr(context,reg_EBP);
816 *(sp-1)=*os_context_pc_addr(context);
818 #elif defined(LISP_FEATURE_X86_64)
819 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
820 /* return address for call_into_lisp: */
821 *(sp-18) = (u64)post_signal_tramp;
823 *(sp-17)=*os_context_register_addr(context,reg_R15);
824 *(sp-16)=*os_context_register_addr(context,reg_R14);
825 *(sp-15)=*os_context_register_addr(context,reg_R13);
826 *(sp-14)=*os_context_register_addr(context,reg_R12);
827 *(sp-13)=*os_context_register_addr(context,reg_R11);
828 *(sp-12)=*os_context_register_addr(context,reg_R10);
829 *(sp-11)=*os_context_register_addr(context,reg_R9);
830 *(sp-10)=*os_context_register_addr(context,reg_R8);
831 *(sp-9)=*os_context_register_addr(context,reg_RDI);
832 *(sp-8)=*os_context_register_addr(context,reg_RSI);
833 /* skip RBP and RSP */
834 *(sp-7)=*os_context_register_addr(context,reg_RBX);
835 *(sp-6)=*os_context_register_addr(context,reg_RDX);
836 *(sp-5)=*os_context_register_addr(context,reg_RCX);
837 *(sp-4)=*os_context_register_addr(context,reg_RAX);
838 *(sp-3)=*context_eflags_addr(context);
839 *(sp-2)=*os_context_register_addr(context,reg_RBP);
840 *(sp-1)=*os_context_pc_addr(context);
842 *os_context_register_addr(context,reg_RDI) =
843 (os_context_register_t)function; /* function */
844 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
845 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
847 struct thread *th=arch_os_get_current_thread();
848 build_fake_control_stack_frames(th,context);
851 #ifdef LISP_FEATURE_X86
852 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
853 *os_context_register_addr(context,reg_ECX) = 0;
854 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
856 *os_context_register_addr(context,reg_UESP) =
857 (os_context_register_t)(sp-15);
859 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
861 #elif defined(LISP_FEATURE_X86_64)
862 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
863 *os_context_register_addr(context,reg_RCX) = 0;
864 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
865 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
867 /* this much of the calling convention is common to all
869 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
870 *os_context_register_addr(context,reg_NARGS) = 0;
871 *os_context_register_addr(context,reg_LIP) =
872 (os_context_register_t)(unsigned long)code;
873 *os_context_register_addr(context,reg_CFP) =
874 (os_context_register_t)(unsigned long)current_control_frame_pointer;
876 #ifdef ARCH_HAS_NPC_REGISTER
877 *os_context_npc_addr(context) =
878 4 + *os_context_pc_addr(context);
880 #ifdef LISP_FEATURE_SPARC
881 *os_context_register_addr(context,reg_CODE) =
882 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
886 #ifdef LISP_FEATURE_SB_THREAD
888 /* FIXME: this function can go away when all lisp handlers are invoked
889 * via arrange_return_to_lisp_function. */
890 void interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
892 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
893 /* let the handler enable interrupts again when it sees fit */
894 sigaddset_deferrable(os_context_sigmask_addr(context));
895 arrange_return_to_lisp_function(context, SymbolFunction(RUN_INTERRUPTION));
900 /* KLUDGE: Theoretically the approach we use for undefined alien
901 * variables should work for functions as well, but on PPC/Darwin
902 * we get bus error at bogus addresses instead, hence this workaround,
903 * that has the added benefit of automatically discriminating between
904 * functions and variables.
906 void undefined_alien_function() {
907 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
910 boolean handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
912 struct thread *th=arch_os_get_current_thread();
914 /* note the os_context hackery here. When the signal handler returns,
915 * it won't go back to what it was doing ... */
916 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
917 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
918 /* We hit the end of the control stack: disable guard page
919 * protection so the error handler has some headroom, protect the
920 * previous page so that we can catch returns from the guard page
922 protect_control_stack_guard_page(0);
923 protect_control_stack_return_guard_page(1);
925 arrange_return_to_lisp_function
926 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
929 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
930 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
931 /* We're returning from the guard page: reprotect it, and
932 * unprotect this one. This works even if we somehow missed
933 * the return-guard-page, and hit it on our way to new
934 * exhaustion instead. */
935 protect_control_stack_guard_page(1);
936 protect_control_stack_return_guard_page(0);
939 else if (addr >= undefined_alien_address &&
940 addr < undefined_alien_address + os_vm_page_size) {
941 arrange_return_to_lisp_function
942 (context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
948 #ifndef LISP_FEATURE_GENCGC
949 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
950 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
951 * whether the signal was due to treading on the mprotect()ed zone -
952 * and if so, arrange for a GC to happen. */
953 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
956 interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
958 os_context_t *context=(os_context_t *) void_context;
960 if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
961 struct thread *thread=arch_os_get_current_thread();
962 clear_auto_gc_trigger();
963 /* Don't flood the system with interrupts if the need to gc is
964 * already noted. This can happen for example when SUB-GC
965 * allocates or after a gc triggered in a WITHOUT-GCING. */
966 if (SymbolValue(GC_PENDING,thread) == NIL) {
967 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
968 if (arch_pseudo_atomic_atomic(context)) {
969 /* set things up so that GC happens when we finish
971 SetSymbolValue(GC_PENDING,T,thread);
972 arch_set_pseudo_atomic_interrupted(context);
974 interrupt_maybe_gc_int(signal,info,void_context);
977 SetSymbolValue(GC_PENDING,T,thread);
987 /* this is also used by gencgc, in alloc() */
989 interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
991 os_context_t *context=(os_context_t *) void_context;
992 struct thread *thread=arch_os_get_current_thread();
994 fake_foreign_function_call(context);
996 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
997 * which case we will be running with no gc trigger barrier
998 * thing for a while. But it shouldn't be long until the end
1001 * FIXME: It would be good to protect the end of dynamic space
1002 * and signal a storage condition from there.
1005 /* Restore the signal mask from the interrupted context before
1006 * calling into Lisp if interrupts are enabled. Why not always?
1008 * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an
1009 * interrupt hits while in SUB-GC, it is deferred and the
1010 * os_context_sigmask of that interrupt is set to block further
1011 * deferrable interrupts (until the first one is
1012 * handled). Unfortunately, that context refers to this place and
1013 * when we return from here the signals will not be blocked.
1015 * A kludgy alternative is to propagate the sigmask change to the
1018 if(SymbolValue(INTERRUPTS_ENABLED,thread)!=NIL)
1019 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1020 #ifdef LISP_FEATURE_SB_THREAD
1023 sigaddset(&new,SIG_STOP_FOR_GC);
1024 thread_sigmask(SIG_UNBLOCK,&new,0);
1027 funcall0(SymbolFunction(SUB_GC));
1029 undo_fake_foreign_function_call(context);
1035 * noise to install handlers
1039 undoably_install_low_level_interrupt_handler (int signal,
1044 struct sigaction sa;
1046 if (0 > signal || signal >= NSIG) {
1047 lose("bad signal number %d", signal);
1050 if (sigismember(&deferrable_sigset,signal))
1051 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1053 sa.sa_sigaction = handler;
1055 sigcopyset(&sa.sa_mask, &blockable_sigset);
1056 sa.sa_flags = SA_SIGINFO | SA_RESTART;
1057 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1058 if((signal==SIG_MEMORY_FAULT)
1059 #ifdef SIG_INTERRUPT_THREAD
1060 || (signal==SIG_INTERRUPT_THREAD)
1063 sa.sa_flags |= SA_ONSTACK;
1066 sigaction(signal, &sa, NULL);
1067 interrupt_low_level_handlers[signal] =
1068 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1071 /* This is called from Lisp. */
1073 install_handler(int signal, void handler(int, siginfo_t*, void*))
1075 struct sigaction sa;
1077 union interrupt_handler oldhandler;
1079 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1082 sigaddset(&new, signal);
1083 thread_sigmask(SIG_BLOCK, &new, &old);
1085 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1086 (unsigned int)interrupt_low_level_handlers[signal]));
1087 if (interrupt_low_level_handlers[signal]==0) {
1088 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1089 ARE_SAME_HANDLER(handler, SIG_IGN)) {
1090 sa.sa_sigaction = handler;
1091 } else if (sigismember(&deferrable_sigset, signal)) {
1092 sa.sa_sigaction = maybe_now_maybe_later;
1094 sa.sa_sigaction = interrupt_handle_now_handler;
1097 sigcopyset(&sa.sa_mask, &blockable_sigset);
1098 sa.sa_flags = SA_SIGINFO | SA_RESTART;
1099 sigaction(signal, &sa, NULL);
1102 oldhandler = interrupt_handlers[signal];
1103 interrupt_handlers[signal].c = handler;
1105 thread_sigmask(SIG_SETMASK, &old, 0);
1107 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1109 return (unsigned long)oldhandler.lisp;
1116 SHOW("entering interrupt_init()");
1117 sigemptyset(&deferrable_sigset);
1118 sigemptyset(&blockable_sigset);
1119 sigaddset_deferrable(&deferrable_sigset);
1120 sigaddset_blockable(&blockable_sigset);
1122 /* Set up high level handler information. */
1123 for (i = 0; i < NSIG; i++) {
1124 interrupt_handlers[i].c =
1125 /* (The cast here blasts away the distinction between
1126 * SA_SIGACTION-style three-argument handlers and
1127 * signal(..)-style one-argument handlers, which is OK
1128 * because it works to call the 1-argument form where the
1129 * 3-argument form is expected.) */
1130 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1133 SHOW("returning from interrupt_init()");