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 = 1; 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)
163 thread_sigmask(SIG_BLOCK, &blockable_sigset, 0);
168 * utility routines used by various signal handlers
172 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
174 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
178 /* Build a fake stack frame or frames */
180 current_control_frame_pointer =
181 (lispobj *)(unsigned long)
182 (*os_context_register_addr(context, reg_CSP));
183 if ((lispobj *)(unsigned long)
184 (*os_context_register_addr(context, reg_CFP))
185 == current_control_frame_pointer) {
186 /* There is a small window during call where the callee's
187 * frame isn't built yet. */
188 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
189 == FUN_POINTER_LOWTAG) {
190 /* We have called, but not built the new frame, so
191 * build it for them. */
192 current_control_frame_pointer[0] =
193 *os_context_register_addr(context, reg_OCFP);
194 current_control_frame_pointer[1] =
195 *os_context_register_addr(context, reg_LRA);
196 current_control_frame_pointer += 8;
197 /* Build our frame on top of it. */
198 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
201 /* We haven't yet called, build our frame as if the
202 * partial frame wasn't there. */
203 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
206 /* We can't tell whether we are still in the caller if it had to
207 * allocate a stack frame due to stack arguments. */
208 /* This observation provoked some past CMUCL maintainer to ask
209 * "Can anything strange happen during return?" */
212 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
215 current_control_stack_pointer = current_control_frame_pointer + 8;
217 current_control_frame_pointer[0] = oldcont;
218 current_control_frame_pointer[1] = NIL;
219 current_control_frame_pointer[2] =
220 (lispobj)(*os_context_register_addr(context, reg_CODE));
225 fake_foreign_function_call(os_context_t *context)
228 struct thread *thread=arch_os_get_current_thread();
230 /* context_index incrementing must not be interrupted */
231 check_blockables_blocked_or_lose();
233 /* Get current Lisp state from context. */
235 dynamic_space_free_pointer =
236 (lispobj *)(unsigned long)
237 (*os_context_register_addr(context, reg_ALLOC));
238 #if defined(LISP_FEATURE_ALPHA)
239 if ((long)dynamic_space_free_pointer & 1) {
240 lose("dead in fake_foreign_function_call, context = %x", context);
245 current_binding_stack_pointer =
246 (lispobj *)(unsigned long)
247 (*os_context_register_addr(context, reg_BSP));
250 build_fake_control_stack_frames(thread,context);
252 /* Do dynamic binding of the active interrupt context index
253 * and save the context in the context array. */
255 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
257 if (context_index >= MAX_INTERRUPTS) {
258 lose("maximum interrupt nesting depth (%d) exceeded", MAX_INTERRUPTS);
261 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
262 make_fixnum(context_index + 1),thread);
264 thread->interrupt_contexts[context_index] = context;
266 /* no longer in Lisp now */
267 foreign_function_call_active = 1;
270 /* blocks all blockable signals. If you are calling from a signal handler,
271 * the usual signal mask will be restored from the context when the handler
272 * finishes. Otherwise, be careful */
275 undo_fake_foreign_function_call(os_context_t *context)
277 struct thread *thread=arch_os_get_current_thread();
278 /* Block all blockable signals. */
279 block_blockable_signals();
281 /* going back into Lisp */
282 foreign_function_call_active = 0;
284 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
288 /* Put the dynamic space free pointer back into the context. */
289 *os_context_register_addr(context, reg_ALLOC) =
290 (unsigned long) dynamic_space_free_pointer;
294 /* a handler for the signal caused by execution of a trap opcode
295 * signalling an internal error */
297 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
302 fake_foreign_function_call(context);
304 if (!internal_errors_enabled) {
305 describe_internal_error(context);
306 /* There's no good way to recover from an internal error
307 * before the Lisp error handling mechanism is set up. */
308 lose("internal error too early in init, can't recover");
311 /* Allocate the SAP object while the interrupts are still
313 context_sap = alloc_sap(context);
315 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
317 SHOW("in interrupt_internal_error");
319 /* Display some rudimentary debugging information about the
320 * error, so that even if the Lisp error handler gets badly
321 * confused, we have a chance to determine what's going on. */
322 describe_internal_error(context);
324 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
325 continuable ? T : NIL);
327 undo_fake_foreign_function_call(context); /* blocks signals again */
329 arch_skip_instruction(context);
333 interrupt_handle_pending(os_context_t *context)
335 struct thread *thread;
336 struct interrupt_data *data;
338 check_blockables_blocked_or_lose();
340 thread=arch_os_get_current_thread();
341 data=thread->interrupt_data;
343 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
344 #ifdef LISP_FEATURE_SB_THREAD
345 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
346 /* another thread has already initiated a gc, this attempt
347 * might as well be cancelled */
348 SetSymbolValue(GC_PENDING,NIL,thread);
349 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
350 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
353 if (SymbolValue(GC_PENDING,thread) != NIL) {
354 /* GC_PENDING is cleared in SUB-GC, or if another thread
355 * is doing a gc already we will get a SIG_STOP_FOR_GC and
356 * that will clear it. */
357 interrupt_maybe_gc_int(0,NULL,context);
359 check_blockables_blocked_or_lose();
362 /* we may be here only to do the gc stuff, if interrupts are
363 * enabled run the pending handler */
364 if (!((SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) ||
366 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
367 (!foreign_function_call_active) &&
369 arch_pseudo_atomic_atomic(context)))) {
371 /* There may be no pending handler, because it was only a gc
372 * that had to be executed or because pseudo atomic triggered
373 * twice for a single interrupt. For the interested reader,
374 * that may happen if an interrupt hits after the interrupted
375 * flag is cleared but before pseduo-atomic is set and a
376 * pseudo atomic is interrupted in that interrupt. */
377 if (data->pending_handler) {
379 /* If we're here as the result of a pseudo-atomic as opposed
380 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
381 * NIL, because maybe_defer_handler sets
382 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
383 SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
385 /* restore the saved signal mask from the original signal (the
386 * one that interrupted us during the critical section) into the
387 * os_context for the signal we're currently in the handler for.
388 * This should ensure that when we return from the handler the
389 * blocked signals are unblocked */
390 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
392 sigemptyset(&data->pending_mask);
393 /* This will break on sparc linux: the deferred handler really wants
394 * to be called with a void_context */
395 run_deferred_handler(data,(void *)context);
401 * the two main signal handlers:
402 * interrupt_handle_now(..)
403 * maybe_now_maybe_later(..)
405 * to which we have added interrupt_handle_now_handler(..). Why?
406 * Well, mostly because the SPARC/Linux platform doesn't quite do
407 * signals the way we want them done. The third argument in the
408 * handler isn't filled in by the kernel properly, so we fix it up
409 * ourselves in the arch_os_get_context(..) function; however, we only
410 * want to do this when we first hit the handler, and not when
411 * interrupt_handle_now(..) is being called from some other handler
412 * (when the fixup will already have been done). -- CSR, 2002-07-23
416 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
418 os_context_t *context = (os_context_t*)void_context;
419 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
420 boolean were_in_lisp;
422 union interrupt_handler handler;
423 check_blockables_blocked_or_lose();
424 if (sigismember(&deferrable_sigset,signal))
425 check_interrupts_enabled_or_lose(context);
427 #ifdef LISP_FEATURE_LINUX
428 /* Under Linux on some architectures, we appear to have to restore
429 the FPU control word from the context, as after the signal is
430 delivered we appear to have a null FPU control word. */
431 os_restore_fp_control(context);
433 handler = interrupt_handlers[signal];
435 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
439 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
440 were_in_lisp = !foreign_function_call_active;
444 fake_foreign_function_call(context);
447 FSHOW_SIGNAL((stderr,
448 "/entering interrupt_handle_now(%d, info, context)\n",
451 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
453 /* This can happen if someone tries to ignore or default one
454 * of the signals we need for runtime support, and the runtime
455 * support decides to pass on it. */
456 lose("no handler for signal %d in interrupt_handle_now(..)", signal);
458 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
459 /* Once we've decided what to do about contexts in a
460 * return-elsewhere world (the original context will no longer
461 * be available; should we copy it or was nobody using it anyway?)
462 * then we should convert this to return-elsewhere */
464 /* CMUCL comment said "Allocate the SAPs while the interrupts
465 * are still disabled.". I (dan, 2003.08.21) assume this is
466 * because we're not in pseudoatomic and allocation shouldn't
467 * be interrupted. In which case it's no longer an issue as
468 * all our allocation from C now goes through a PA wrapper,
469 * but still, doesn't hurt.
471 * Yeah, but non-gencgc platforms that don't really wrap
472 * allocation in PA. MG - 2005-08-29 */
474 lispobj info_sap,context_sap = alloc_sap(context);
475 info_sap = alloc_sap(info);
476 /* Leave deferrable signals blocked, the handler itself will
477 * allow signals again when it sees fit. */
478 #ifdef LISP_FEATURE_SB_THREAD
481 sigemptyset(&unblock);
482 sigaddset(&unblock, SIG_STOP_FOR_GC);
483 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
487 FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n"));
489 funcall3(handler.lisp,
495 FSHOW_SIGNAL((stderr,"/calling C-level handler\n"));
497 /* Allow signals again. */
498 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
500 (*handler.c)(signal, info, void_context);
503 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
507 undo_fake_foreign_function_call(context); /* block signals again */
510 FSHOW_SIGNAL((stderr,
511 "/returning from interrupt_handle_now(%d, info, context)\n",
515 /* This is called at the end of a critical section if the indications
516 * are that some signal was deferred during the section. Note that as
517 * far as C or the kernel is concerned we dealt with the signal
518 * already; we're just doing the Lisp-level processing now that we
522 run_deferred_handler(struct interrupt_data *data, void *v_context) {
523 /* The pending_handler may enable interrupts and then another
524 * interrupt may hit, overwrite interrupt_data, so reset the
525 * pending handler before calling it. Trust the handler to finish
526 * with the siginfo before enabling interrupts. */
527 void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler;
528 data->pending_handler=0;
529 (*pending_handler)(data->pending_signal,&(data->pending_info), v_context);
533 maybe_defer_handler(void *handler, struct interrupt_data *data,
534 int signal, siginfo_t *info, os_context_t *context)
536 struct thread *thread=arch_os_get_current_thread();
538 check_blockables_blocked_or_lose();
540 if (SymbolValue(INTERRUPT_PENDING,thread) != NIL)
541 lose("interrupt already pending");
542 /* If interrupts are disabled then INTERRUPT_PENDING is set and
543 * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo
544 * atomic section inside a WITHOUT-INTERRUPTS.
546 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
547 store_signal_data_for_later(data,handler,signal,info,context);
548 SetSymbolValue(INTERRUPT_PENDING, T,thread);
549 FSHOW_SIGNAL((stderr,
550 "/maybe_defer_handler(%x,%d),thread=%lu: deferred\n",
551 (unsigned int)handler,signal,
552 (unsigned long)thread->os_thread));
555 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
556 * actually use its argument for anything on x86, so this branch
557 * may succeed even when context is null (gencgc alloc()) */
559 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
560 /* FIXME: this foreign_function_call_active test is dubious at
561 * best. If a foreign call is made in a pseudo atomic section
562 * (?) or more likely a pseudo atomic section is in a foreign
563 * call then an interrupt is executed immediately. Maybe it
564 * has to do with C code not maintaining pseudo atomic
565 * properly. MG - 2005-08-10 */
566 (!foreign_function_call_active) &&
568 arch_pseudo_atomic_atomic(context)) {
569 store_signal_data_for_later(data,handler,signal,info,context);
570 arch_set_pseudo_atomic_interrupted(context);
571 FSHOW_SIGNAL((stderr,
572 "/maybe_defer_handler(%x,%d),thread=%lu: deferred(PA)\n",
573 (unsigned int)handler,signal,
574 (unsigned long)thread->os_thread));
577 FSHOW_SIGNAL((stderr,
578 "/maybe_defer_handler(%x,%d),thread=%lu: not deferred\n",
579 (unsigned int)handler,signal,
580 (unsigned long)thread->os_thread));
585 store_signal_data_for_later (struct interrupt_data *data, void *handler,
587 siginfo_t *info, os_context_t *context)
589 if (data->pending_handler)
590 lose("tried to overwrite pending interrupt handler %x with %x\n",
591 data->pending_handler, handler);
593 lose("tried to defer null interrupt handler\n");
594 data->pending_handler = handler;
595 data->pending_signal = signal;
597 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
599 /* the signal mask in the context (from before we were
600 * interrupted) is copied to be restored when
601 * run_deferred_handler happens. Then the usually-blocked
602 * signals are added to the mask in the context so that we are
603 * running with blocked signals when the handler returns */
604 sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context));
605 sigaddset_deferrable(os_context_sigmask_addr(context));
610 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
612 os_context_t *context = arch_os_get_context(&void_context);
613 struct thread *thread=arch_os_get_current_thread();
614 struct interrupt_data *data=thread->interrupt_data;
615 #ifdef LISP_FEATURE_LINUX
616 os_restore_fp_control(context);
618 if(maybe_defer_handler(interrupt_handle_now,data,signal,info,context))
620 interrupt_handle_now(signal, info, context);
621 #ifdef LISP_FEATURE_DARWIN
622 /* Work around G5 bug */
623 DARWIN_FIX_CONTEXT(context);
628 low_level_interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
630 os_context_t *context = (os_context_t*)void_context;
632 #ifdef LISP_FEATURE_LINUX
633 os_restore_fp_control(context);
635 check_blockables_blocked_or_lose();
636 check_interrupts_enabled_or_lose(context);
637 interrupt_low_level_handlers[signal](signal, info, void_context);
638 #ifdef LISP_FEATURE_DARWIN
639 /* Work around G5 bug */
640 DARWIN_FIX_CONTEXT(context);
645 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
647 os_context_t *context = arch_os_get_context(&void_context);
648 struct thread *thread=arch_os_get_current_thread();
649 struct interrupt_data *data=thread->interrupt_data;
650 #ifdef LISP_FEATURE_LINUX
651 os_restore_fp_control(context);
653 if(maybe_defer_handler(low_level_interrupt_handle_now,data,
654 signal,info,context))
656 low_level_interrupt_handle_now(signal, info, context);
657 #ifdef LISP_FEATURE_DARWIN
658 /* Work around G5 bug */
659 DARWIN_FIX_CONTEXT(context);
663 #ifdef LISP_FEATURE_SB_THREAD
666 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
668 os_context_t *context = arch_os_get_context(&void_context);
669 struct thread *thread=arch_os_get_current_thread();
672 if ((arch_pseudo_atomic_atomic(context) ||
673 SymbolValue(GC_INHIBIT,thread) != NIL)) {
674 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
675 if (SymbolValue(GC_INHIBIT,thread) == NIL)
676 arch_set_pseudo_atomic_interrupted(context);
677 FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred\n",
680 /* need the context stored so it can have registers scavenged */
681 fake_foreign_function_call(context);
683 sigfillset(&ss); /* Block everything. */
684 thread_sigmask(SIG_BLOCK,&ss,0);
686 /* The GC can't tell if a thread is a zombie, so this would be a
687 * good time to let the kernel reap any of our children in that
688 * awful state, to stop them from being waited for indefinitely.
689 * Userland reaping is done later when GC is finished */
690 if(thread->state!=STATE_RUNNING) {
691 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
692 fixnum_value(thread->state));
694 thread->state=STATE_SUSPENDED;
695 FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread));
697 sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
698 /* It is possible to get SIGCONT (and probably other
699 * non-blockable signals) here. */
700 while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC);
701 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
702 if(thread->state!=STATE_RUNNING) {
703 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
704 fixnum_value(thread->state));
707 undo_fake_foreign_function_call(context);
713 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
715 os_context_t *context = arch_os_get_context(&void_context);
716 interrupt_handle_now(signal, info, context);
717 #ifdef LISP_FEATURE_DARWIN
718 DARWIN_FIX_CONTEXT(context);
723 * stuff to detect and handle hitting the GC trigger
726 #ifndef LISP_FEATURE_GENCGC
727 /* since GENCGC has its own way to record trigger */
729 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
731 if (current_auto_gc_trigger == NULL)
734 void *badaddr=arch_get_bad_addr(signal,info,context);
735 return (badaddr >= (void *)current_auto_gc_trigger &&
736 badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE));
741 /* manipulate the signal context and stack such that when the handler
742 * returns, it will call function instead of whatever it was doing
746 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
747 int *context_eflags_addr(os_context_t *context);
750 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
751 extern void post_signal_tramp(void);
752 void arrange_return_to_lisp_function(os_context_t *context, lispobj function)
754 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
755 void * fun=native_pointer(function);
756 void *code = &(((struct simple_fun *) fun)->code);
759 /* Build a stack frame showing `interrupted' so that the
760 * user's backtrace makes (as much) sense (as usual) */
762 /* FIXME: what about restoring fp state? */
763 /* FIXME: what about restoring errno? */
764 #ifdef LISP_FEATURE_X86
765 /* Suppose the existence of some function that saved all
766 * registers, called call_into_lisp, then restored GP registers and
767 * returned. It would look something like this:
775 pushl {address of function to call}
776 call 0x8058db0 <call_into_lisp>
783 * What we do here is set up the stack that call_into_lisp would
784 * expect to see if it had been called by this code, and frob the
785 * signal context so that signal return goes directly to call_into_lisp,
786 * and when that function (and the lisp function it invoked) returns,
787 * it returns to the second half of this imaginary function which
788 * restores all registers and returns to C
790 * For this to work, the latter part of the imaginary function
791 * must obviously exist in reality. That would be post_signal_tramp
794 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
796 /* return address for call_into_lisp: */
797 *(sp-15) = (u32)post_signal_tramp;
798 *(sp-14) = function; /* args for call_into_lisp : function*/
799 *(sp-13) = 0; /* arg array */
800 *(sp-12) = 0; /* no. args */
801 /* this order matches that used in POPAD */
802 *(sp-11)=*os_context_register_addr(context,reg_EDI);
803 *(sp-10)=*os_context_register_addr(context,reg_ESI);
805 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
806 /* POPAD ignores the value of ESP: */
808 *(sp-7)=*os_context_register_addr(context,reg_EBX);
810 *(sp-6)=*os_context_register_addr(context,reg_EDX);
811 *(sp-5)=*os_context_register_addr(context,reg_ECX);
812 *(sp-4)=*os_context_register_addr(context,reg_EAX);
813 *(sp-3)=*context_eflags_addr(context);
814 *(sp-2)=*os_context_register_addr(context,reg_EBP);
815 *(sp-1)=*os_context_pc_addr(context);
817 #elif defined(LISP_FEATURE_X86_64)
818 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
819 /* return address for call_into_lisp: */
820 *(sp-18) = (u64)post_signal_tramp;
822 *(sp-17)=*os_context_register_addr(context,reg_R15);
823 *(sp-16)=*os_context_register_addr(context,reg_R14);
824 *(sp-15)=*os_context_register_addr(context,reg_R13);
825 *(sp-14)=*os_context_register_addr(context,reg_R12);
826 *(sp-13)=*os_context_register_addr(context,reg_R11);
827 *(sp-12)=*os_context_register_addr(context,reg_R10);
828 *(sp-11)=*os_context_register_addr(context,reg_R9);
829 *(sp-10)=*os_context_register_addr(context,reg_R8);
830 *(sp-9)=*os_context_register_addr(context,reg_RDI);
831 *(sp-8)=*os_context_register_addr(context,reg_RSI);
832 /* skip RBP and RSP */
833 *(sp-7)=*os_context_register_addr(context,reg_RBX);
834 *(sp-6)=*os_context_register_addr(context,reg_RDX);
835 *(sp-5)=*os_context_register_addr(context,reg_RCX);
836 *(sp-4)=*os_context_register_addr(context,reg_RAX);
837 *(sp-3)=*context_eflags_addr(context);
838 *(sp-2)=*os_context_register_addr(context,reg_RBP);
839 *(sp-1)=*os_context_pc_addr(context);
841 *os_context_register_addr(context,reg_RDI) =
842 (os_context_register_t)function; /* function */
843 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
844 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
846 struct thread *th=arch_os_get_current_thread();
847 build_fake_control_stack_frames(th,context);
850 #ifdef LISP_FEATURE_X86
851 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
852 *os_context_register_addr(context,reg_ECX) = 0;
853 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
855 *os_context_register_addr(context,reg_UESP) =
856 (os_context_register_t)(sp-15);
858 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
860 #elif defined(LISP_FEATURE_X86_64)
861 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
862 *os_context_register_addr(context,reg_RCX) = 0;
863 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
864 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
866 /* this much of the calling convention is common to all
868 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
869 *os_context_register_addr(context,reg_NARGS) = 0;
870 *os_context_register_addr(context,reg_LIP) =
871 (os_context_register_t)(unsigned long)code;
872 *os_context_register_addr(context,reg_CFP) =
873 (os_context_register_t)(unsigned long)current_control_frame_pointer;
875 #ifdef ARCH_HAS_NPC_REGISTER
876 *os_context_npc_addr(context) =
877 4 + *os_context_pc_addr(context);
879 #ifdef LISP_FEATURE_SPARC
880 *os_context_register_addr(context,reg_CODE) =
881 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
885 #ifdef LISP_FEATURE_SB_THREAD
887 /* FIXME: this function can go away when all lisp handlers are invoked
888 * via arrange_return_to_lisp_function. */
889 void interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
891 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
892 /* let the handler enable interrupts again when it sees fit */
893 sigaddset_deferrable(os_context_sigmask_addr(context));
894 arrange_return_to_lisp_function(context, SymbolFunction(RUN_INTERRUPTION));
899 /* KLUDGE: Theoretically the approach we use for undefined alien
900 * variables should work for functions as well, but on PPC/Darwin
901 * we get bus error at bogus addresses instead, hence this workaround,
902 * that has the added benefit of automatically discriminating between
903 * functions and variables.
905 void undefined_alien_function() {
906 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
909 boolean handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
911 struct thread *th=arch_os_get_current_thread();
913 /* note the os_context hackery here. When the signal handler returns,
914 * it won't go back to what it was doing ... */
915 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
916 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
917 /* We hit the end of the control stack: disable guard page
918 * protection so the error handler has some headroom, protect the
919 * previous page so that we can catch returns from the guard page
921 protect_control_stack_guard_page(0);
922 protect_control_stack_return_guard_page(1);
924 arrange_return_to_lisp_function
925 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
928 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
929 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
930 /* We're returning from the guard page: reprotect it, and
931 * unprotect this one. This works even if we somehow missed
932 * the return-guard-page, and hit it on our way to new
933 * exhaustion instead. */
934 protect_control_stack_guard_page(1);
935 protect_control_stack_return_guard_page(0);
938 else if (addr >= undefined_alien_address &&
939 addr < undefined_alien_address + os_vm_page_size) {
940 arrange_return_to_lisp_function
941 (context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
947 #ifndef LISP_FEATURE_GENCGC
948 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
949 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
950 * whether the signal was due to treading on the mprotect()ed zone -
951 * and if so, arrange for a GC to happen. */
952 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
955 interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
957 os_context_t *context=(os_context_t *) void_context;
959 if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
960 struct thread *thread=arch_os_get_current_thread();
961 clear_auto_gc_trigger();
962 /* Don't flood the system with interrupts if the need to gc is
963 * already noted. This can happen for example when SUB-GC
964 * allocates or after a gc triggered in a WITHOUT-GCING. */
965 if (SymbolValue(GC_PENDING,thread) == NIL) {
966 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
967 if (arch_pseudo_atomic_atomic(context)) {
968 /* set things up so that GC happens when we finish
970 SetSymbolValue(GC_PENDING,T,thread);
971 arch_set_pseudo_atomic_interrupted(context);
973 interrupt_maybe_gc_int(signal,info,void_context);
976 SetSymbolValue(GC_PENDING,T,thread);
986 /* this is also used by gencgc, in alloc() */
988 interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
990 os_context_t *context=(os_context_t *) void_context;
991 struct thread *thread=arch_os_get_current_thread();
993 fake_foreign_function_call(context);
995 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
996 * which case we will be running with no gc trigger barrier
997 * thing for a while. But it shouldn't be long until the end
1000 * FIXME: It would be good to protect the end of dynamic space
1001 * and signal a storage condition from there.
1004 /* Restore the signal mask from the interrupted context before
1005 * calling into Lisp if interrupts are enabled. Why not always?
1007 * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an
1008 * interrupt hits while in SUB-GC, it is deferred and the
1009 * os_context_sigmask of that interrupt is set to block further
1010 * deferrable interrupts (until the first one is
1011 * handled). Unfortunately, that context refers to this place and
1012 * when we return from here the signals will not be blocked.
1014 * A kludgy alternative is to propagate the sigmask change to the
1017 if(SymbolValue(INTERRUPTS_ENABLED,thread)!=NIL)
1018 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1019 #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);
1033 #ifndef LISP_FEATURE_SIGACTION_NODEFER_WORKS
1035 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if
1036 * they are blocked, in Linux 2.6 the default handler is invoked
1037 * instead that usually coredumps. One might hastily think that adding
1038 * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then
1039 * the whole sa_mask is ignored and instead of not adding the signal
1040 * in question to the mask. That means if it's not blockable the
1041 * signal must be unblocked at the beginning of signal handlers.
1044 unblock_me_trampoline(int signal, siginfo_t *info, void *void_context)
1047 sigemptyset(&unblock);
1048 sigaddset(&unblock, signal);
1049 thread_sigmask(SIG_UNBLOCK, &unblock, 0);
1050 (*interrupt_low_level_handlers[signal])(signal, info, void_context);
1057 * noise to install handlers
1061 undoably_install_low_level_interrupt_handler (int signal,
1066 struct sigaction sa;
1068 if (0 > signal || signal >= NSIG) {
1069 lose("bad signal number %d", signal);
1072 if (sigismember(&deferrable_sigset,signal))
1073 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1074 #ifndef LISP_FEATURE_SIGACTION_NODEFER_WORKS
1075 else if (!sigismember(&blockable_sigset, signal))
1076 sa.sa_sigaction = unblock_me_trampoline;
1079 sa.sa_sigaction = handler;
1081 sigcopyset(&sa.sa_mask, &blockable_sigset);
1082 sa.sa_flags = SA_SIGINFO | SA_RESTART
1083 #ifdef LISP_FEATURE_SIGACTION_NODEFER_WORKS
1087 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1088 if((signal==SIG_MEMORY_FAULT)
1089 #ifdef SIG_INTERRUPT_THREAD
1090 || (signal==SIG_INTERRUPT_THREAD)
1093 sa.sa_flags |= SA_ONSTACK;
1096 sigaction(signal, &sa, NULL);
1097 interrupt_low_level_handlers[signal] =
1098 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1101 /* This is called from Lisp. */
1103 install_handler(int signal, void handler(int, siginfo_t*, void*))
1105 struct sigaction sa;
1107 union interrupt_handler oldhandler;
1109 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1112 sigaddset(&new, signal);
1113 thread_sigmask(SIG_BLOCK, &new, &old);
1115 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1116 (unsigned int)interrupt_low_level_handlers[signal]));
1117 if (interrupt_low_level_handlers[signal]==0) {
1118 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1119 ARE_SAME_HANDLER(handler, SIG_IGN)) {
1120 sa.sa_sigaction = handler;
1121 } else if (sigismember(&deferrable_sigset, signal)) {
1122 sa.sa_sigaction = maybe_now_maybe_later;
1124 sa.sa_sigaction = interrupt_handle_now_handler;
1127 sigcopyset(&sa.sa_mask, &blockable_sigset);
1128 sa.sa_flags = SA_SIGINFO | SA_RESTART
1129 #ifdef LISP_FEATURE_SIGACTION_NODEFER_WORKS
1133 sigaction(signal, &sa, NULL);
1136 oldhandler = interrupt_handlers[signal];
1137 interrupt_handlers[signal].c = handler;
1139 thread_sigmask(SIG_SETMASK, &old, 0);
1141 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1143 return (unsigned long)oldhandler.lisp;
1150 SHOW("entering interrupt_init()");
1151 sigemptyset(&deferrable_sigset);
1152 sigemptyset(&blockable_sigset);
1153 sigaddset_deferrable(&deferrable_sigset);
1154 sigaddset_blockable(&blockable_sigset);
1156 /* Set up high level handler information. */
1157 for (i = 0; i < NSIG; i++) {
1158 interrupt_handlers[i].c =
1159 /* (The cast here blasts away the distinction between
1160 * SA_SIGACTION-style three-argument handlers and
1161 * signal(..)-style one-argument handlers, which is OK
1162 * because it works to call the 1-argument form where the
1163 * 3-argument form is expected.) */
1164 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1167 SHOW("returning from interrupt_init()");