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);
87 sigaddset(s, SIGTSTP);
88 sigaddset(s, SIGCHLD);
90 sigaddset(s, SIGXCPU);
91 sigaddset(s, SIGXFSZ);
92 sigaddset(s, SIGVTALRM);
93 sigaddset(s, SIGPROF);
94 sigaddset(s, SIGWINCH);
95 sigaddset(s, SIGUSR1);
96 sigaddset(s, SIGUSR2);
97 #ifdef LISP_FEATURE_SB_THREAD
98 sigaddset(s, SIG_INTERRUPT_THREAD);
102 void sigaddset_blockable(sigset_t *s)
104 sigaddset_deferrable(s);
105 #ifdef LISP_FEATURE_SB_THREAD
106 sigaddset(s, SIG_STOP_FOR_GC);
110 /* initialized in interrupt_init */
111 static sigset_t deferrable_sigset;
112 static sigset_t blockable_sigset;
114 inline static void 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 struct interrupt_data * global_interrupt_data;
149 /* At the toplevel repl we routinely call this function. The signal
150 * mask ought to be clear anyway most of the time, but may be non-zero
151 * if we were interrupted e.g. while waiting for a queue. */
153 void reset_signal_mask ()
157 thread_sigmask(SIG_SETMASK,&new,0);
160 void block_deferrable_signals_and_inhibit_gc ()
162 struct thread *thread=arch_os_get_current_thread();
165 sigaddset_deferrable(&block);
166 thread_sigmask(SIG_BLOCK, &block, 0);
167 bind_variable(GC_INHIBIT,T,thread);
170 static void block_blockable_signals ()
174 sigaddset_blockable(&block);
175 thread_sigmask(SIG_BLOCK, &block, 0);
180 * utility routines used by various signal handlers
184 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
186 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
190 /* Build a fake stack frame or frames */
192 current_control_frame_pointer =
193 (lispobj *)(*os_context_register_addr(context, reg_CSP));
194 if ((lispobj *)(*os_context_register_addr(context, reg_CFP))
195 == current_control_frame_pointer) {
196 /* There is a small window during call where the callee's
197 * frame isn't built yet. */
198 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
199 == FUN_POINTER_LOWTAG) {
200 /* We have called, but not built the new frame, so
201 * build it for them. */
202 current_control_frame_pointer[0] =
203 *os_context_register_addr(context, reg_OCFP);
204 current_control_frame_pointer[1] =
205 *os_context_register_addr(context, reg_LRA);
206 current_control_frame_pointer += 8;
207 /* Build our frame on top of it. */
208 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
211 /* We haven't yet called, build our frame as if the
212 * partial frame wasn't there. */
213 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
216 /* We can't tell whether we are still in the caller if it had to
217 * allocate a stack frame due to stack arguments. */
218 /* This observation provoked some past CMUCL maintainer to ask
219 * "Can anything strange happen during return?" */
222 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
225 current_control_stack_pointer = current_control_frame_pointer + 8;
227 current_control_frame_pointer[0] = oldcont;
228 current_control_frame_pointer[1] = NIL;
229 current_control_frame_pointer[2] =
230 (lispobj)(*os_context_register_addr(context, reg_CODE));
235 fake_foreign_function_call(os_context_t *context)
238 struct thread *thread=arch_os_get_current_thread();
240 /* context_index incrementing must not be interrupted */
241 check_blockables_blocked_or_lose();
243 /* Get current Lisp state from context. */
245 dynamic_space_free_pointer =
246 (lispobj *)(*os_context_register_addr(context, reg_ALLOC));
247 #if defined(LISP_FEATURE_ALPHA)
248 if ((long)dynamic_space_free_pointer & 1) {
249 lose("dead in fake_foreign_function_call, context = %x", context);
254 current_binding_stack_pointer =
255 (lispobj *)(*os_context_register_addr(context, reg_BSP));
258 build_fake_control_stack_frames(thread,context);
260 /* Do dynamic binding of the active interrupt context index
261 * and save the context in the context array. */
263 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
265 if (context_index >= MAX_INTERRUPTS) {
266 lose("maximum interrupt nesting depth (%d) exceeded", MAX_INTERRUPTS);
269 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
270 make_fixnum(context_index + 1),thread);
272 thread->interrupt_contexts[context_index] = context;
274 /* no longer in Lisp now */
275 foreign_function_call_active = 1;
278 /* blocks all blockable signals. If you are calling from a signal handler,
279 * the usual signal mask will be restored from the context when the handler
280 * finishes. Otherwise, be careful */
283 undo_fake_foreign_function_call(os_context_t *context)
285 struct thread *thread=arch_os_get_current_thread();
286 /* Block all blockable signals. */
287 block_blockable_signals();
289 /* going back into Lisp */
290 foreign_function_call_active = 0;
292 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
296 /* Put the dynamic space free pointer back into the context. */
297 *os_context_register_addr(context, reg_ALLOC) =
298 (unsigned long) dynamic_space_free_pointer;
302 /* a handler for the signal caused by execution of a trap opcode
303 * signalling an internal error */
305 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
308 lispobj context_sap = 0;
310 check_blockables_blocked_or_lose();
311 fake_foreign_function_call(context);
313 /* Allocate the SAP object while the interrupts are still
315 if (internal_errors_enabled) {
316 context_sap = alloc_sap(context);
319 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
321 if (internal_errors_enabled) {
322 SHOW("in interrupt_internal_error");
324 /* Display some rudimentary debugging information about the
325 * error, so that even if the Lisp error handler gets badly
326 * confused, we have a chance to determine what's going on. */
327 describe_internal_error(context);
329 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
330 continuable ? T : NIL);
332 describe_internal_error(context);
333 /* There's no good way to recover from an internal error
334 * before the Lisp error handling mechanism is set up. */
335 lose("internal error too early in init, can't recover");
337 undo_fake_foreign_function_call(context); /* blocks signals again */
339 arch_skip_instruction(context);
344 interrupt_handle_pending(os_context_t *context)
346 struct thread *thread;
347 struct interrupt_data *data;
349 check_blockables_blocked_or_lose();
351 thread=arch_os_get_current_thread();
352 data=thread->interrupt_data;
354 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
355 #ifdef LISP_FEATURE_SB_THREAD
356 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
357 /* another thread has already initiated a gc, this attempt
358 * might as well be cancelled */
359 SetSymbolValue(GC_PENDING,NIL,thread);
360 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
361 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
364 if (SymbolValue(GC_PENDING,thread) != NIL) {
365 /* GC_PENDING is cleared in SUB-GC, or if another thread
366 * is doing a gc already we will get a SIG_STOP_FOR_GC and
367 * that will clear it. */
368 interrupt_maybe_gc_int(0,NULL,context);
370 check_blockables_blocked_or_lose();
373 /* we may be here only to do the gc stuff, if interrupts are
374 * enabled run the pending handler */
375 if (!((SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) ||
377 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
378 (!foreign_function_call_active) &&
380 arch_pseudo_atomic_atomic(context)))) {
382 /* There may be no pending handler, because it was only a gc
383 * that had to be executed or because pseudo atomic triggered
384 * twice for a single interrupt. For the interested reader,
385 * that may happen if an interrupt hits after the interrupted
386 * flag is cleared but before pseduo-atomic is set and a
387 * pseudo atomic is interrupted in that interrupt. */
388 if (data->pending_handler) {
390 /* If we're here as the result of a pseudo-atomic as opposed
391 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
392 * NIL, because maybe_defer_handler sets
393 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
394 SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
396 /* restore the saved signal mask from the original signal (the
397 * one that interrupted us during the critical section) into the
398 * os_context for the signal we're currently in the handler for.
399 * This should ensure that when we return from the handler the
400 * blocked signals are unblocked */
401 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
403 sigemptyset(&data->pending_mask);
404 /* This will break on sparc linux: the deferred handler really wants
405 * to be called with a void_context */
406 run_deferred_handler(data,(void *)context);
412 * the two main signal handlers:
413 * interrupt_handle_now(..)
414 * maybe_now_maybe_later(..)
416 * to which we have added interrupt_handle_now_handler(..). Why?
417 * Well, mostly because the SPARC/Linux platform doesn't quite do
418 * signals the way we want them done. The third argument in the
419 * handler isn't filled in by the kernel properly, so we fix it up
420 * ourselves in the arch_os_get_context(..) function; however, we only
421 * want to do this when we first hit the handler, and not when
422 * interrupt_handle_now(..) is being called from some other handler
423 * (when the fixup will already have been done). -- CSR, 2002-07-23
427 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
429 os_context_t *context = (os_context_t*)void_context;
430 struct thread *thread=arch_os_get_current_thread();
431 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
432 boolean were_in_lisp;
434 union interrupt_handler handler;
435 check_blockables_blocked_or_lose();
436 check_interrupts_enabled_or_lose(context);
438 #ifdef LISP_FEATURE_LINUX
439 /* Under Linux on some architectures, we appear to have to restore
440 the FPU control word from the context, as after the signal is
441 delivered we appear to have a null FPU control word. */
442 os_restore_fp_control(context);
444 handler = thread->interrupt_data->interrupt_handlers[signal];
446 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
450 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
451 were_in_lisp = !foreign_function_call_active;
455 fake_foreign_function_call(context);
458 FSHOW_SIGNAL((stderr,
459 "/entering interrupt_handle_now(%d, info, context)\n",
462 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
464 /* This can happen if someone tries to ignore or default one
465 * of the signals we need for runtime support, and the runtime
466 * support decides to pass on it. */
467 lose("no handler for signal %d in interrupt_handle_now(..)", signal);
469 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
470 /* Once we've decided what to do about contexts in a
471 * return-elsewhere world (the original context will no longer
472 * be available; should we copy it or was nobody using it anyway?)
473 * then we should convert this to return-elsewhere */
475 /* CMUCL comment said "Allocate the SAPs while the interrupts
476 * are still disabled.". I (dan, 2003.08.21) assume this is
477 * because we're not in pseudoatomic and allocation shouldn't
478 * be interrupted. In which case it's no longer an issue as
479 * all our allocation from C now goes through a PA wrapper,
480 * but still, doesn't hurt */
482 lispobj info_sap,context_sap = alloc_sap(context);
483 info_sap = alloc_sap(info);
484 /* Allow signals again. */
485 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 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,
619 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;
632 struct thread *thread=arch_os_get_current_thread();
633 struct interrupt_data *data=
634 thread ? thread->interrupt_data : global_interrupt_data;
636 #ifdef LISP_FEATURE_LINUX
637 os_restore_fp_control(context);
639 check_blockables_blocked_or_lose();
640 check_interrupts_enabled_or_lose(context);
641 (*data->interrupt_low_level_handlers[signal])
642 (signal, info, void_context);
643 #ifdef LISP_FEATURE_DARWIN
644 /* Work around G5 bug */
645 DARWIN_FIX_CONTEXT(context);
650 low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
652 os_context_t *context = arch_os_get_context(&void_context);
653 struct thread *thread=arch_os_get_current_thread();
654 struct interrupt_data *data=
655 thread ? thread->interrupt_data : global_interrupt_data;
656 #ifdef LISP_FEATURE_LINUX
657 os_restore_fp_control(context);
659 if(maybe_defer_handler(low_level_interrupt_handle_now,data,
660 signal,info,context))
662 low_level_interrupt_handle_now(signal, info, context);
663 #ifdef LISP_FEATURE_DARWIN
664 /* Work around G5 bug */
665 DARWIN_FIX_CONTEXT(context);
669 #ifdef LISP_FEATURE_SB_THREAD
672 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
674 os_context_t *context = arch_os_get_context(&void_context);
675 struct thread *thread=arch_os_get_current_thread();
679 if ((arch_pseudo_atomic_atomic(context) ||
680 SymbolValue(GC_INHIBIT,thread) != NIL)) {
681 SetSymbolValue(STOP_FOR_GC_PENDING,T,thread);
682 if (SymbolValue(GC_INHIBIT,thread) == NIL)
683 arch_set_pseudo_atomic_interrupted(context);
684 FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred\n",
687 /* need the context stored so it can have registers scavenged */
688 fake_foreign_function_call(context);
691 for(i=1;i<NSIG;i++) sigaddset(&ss,i); /* Block everything. */
692 thread_sigmask(SIG_BLOCK,&ss,0);
694 /* The GC can't tell if a thread is a zombie, so this would be a
695 * good time to let the kernel reap any of our children in that
696 * awful state, to stop them from being waited for indefinitely.
697 * Userland reaping is done later when GC is finished */
698 if(thread->state!=STATE_RUNNING) {
699 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
700 fixnum_value(thread->state));
702 thread->state=STATE_SUSPENDED;
703 FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread));
705 sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
707 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
708 if(thread->state!=STATE_RUNNING) {
709 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
710 fixnum_value(thread->state));
713 undo_fake_foreign_function_call(context);
719 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
721 os_context_t *context = arch_os_get_context(&void_context);
722 interrupt_handle_now(signal, info, context);
723 #ifdef LISP_FEATURE_DARWIN
724 DARWIN_FIX_CONTEXT(context);
729 * stuff to detect and handle hitting the GC trigger
732 #ifndef LISP_FEATURE_GENCGC
733 /* since GENCGC has its own way to record trigger */
735 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
737 if (current_auto_gc_trigger == NULL)
740 void *badaddr=arch_get_bad_addr(signal,info,context);
741 return (badaddr >= (void *)current_auto_gc_trigger &&
742 badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE));
747 /* manipulate the signal context and stack such that when the handler
748 * returns, it will call function instead of whatever it was doing
752 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
753 int *context_eflags_addr(os_context_t *context);
756 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
757 extern void post_signal_tramp(void);
758 void arrange_return_to_lisp_function(os_context_t *context, lispobj function)
760 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
761 void * fun=native_pointer(function);
762 void *code = &(((struct simple_fun *) fun)->code);
765 /* Build a stack frame showing `interrupted' so that the
766 * user's backtrace makes (as much) sense (as usual) */
768 /* FIXME: what about restoring fp state? */
769 /* FIXME: what about restoring errno? */
770 #ifdef LISP_FEATURE_X86
771 /* Suppose the existence of some function that saved all
772 * registers, called call_into_lisp, then restored GP registers and
773 * returned. It would look something like this:
781 pushl {address of function to call}
782 call 0x8058db0 <call_into_lisp>
789 * What we do here is set up the stack that call_into_lisp would
790 * expect to see if it had been called by this code, and frob the
791 * signal context so that signal return goes directly to call_into_lisp,
792 * and when that function (and the lisp function it invoked) returns,
793 * it returns to the second half of this imaginary function which
794 * restores all registers and returns to C
796 * For this to work, the latter part of the imaginary function
797 * must obviously exist in reality. That would be post_signal_tramp
800 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
802 /* return address for call_into_lisp: */
803 *(sp-15) = (u32)post_signal_tramp;
804 *(sp-14) = function; /* args for call_into_lisp : function*/
805 *(sp-13) = 0; /* arg array */
806 *(sp-12) = 0; /* no. args */
807 /* this order matches that used in POPAD */
808 *(sp-11)=*os_context_register_addr(context,reg_EDI);
809 *(sp-10)=*os_context_register_addr(context,reg_ESI);
811 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
812 /* POPAD ignores the value of ESP: */
814 *(sp-7)=*os_context_register_addr(context,reg_EBX);
816 *(sp-6)=*os_context_register_addr(context,reg_EDX);
817 *(sp-5)=*os_context_register_addr(context,reg_ECX);
818 *(sp-4)=*os_context_register_addr(context,reg_EAX);
819 *(sp-3)=*context_eflags_addr(context);
820 *(sp-2)=*os_context_register_addr(context,reg_EBP);
821 *(sp-1)=*os_context_pc_addr(context);
823 #elif defined(LISP_FEATURE_X86_64)
824 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
825 /* return address for call_into_lisp: */
826 *(sp-18) = (u64)post_signal_tramp;
828 *(sp-17)=*os_context_register_addr(context,reg_R15);
829 *(sp-16)=*os_context_register_addr(context,reg_R14);
830 *(sp-15)=*os_context_register_addr(context,reg_R13);
831 *(sp-14)=*os_context_register_addr(context,reg_R12);
832 *(sp-13)=*os_context_register_addr(context,reg_R11);
833 *(sp-12)=*os_context_register_addr(context,reg_R10);
834 *(sp-11)=*os_context_register_addr(context,reg_R9);
835 *(sp-10)=*os_context_register_addr(context,reg_R8);
836 *(sp-9)=*os_context_register_addr(context,reg_RDI);
837 *(sp-8)=*os_context_register_addr(context,reg_RSI);
838 /* skip RBP and RSP */
839 *(sp-7)=*os_context_register_addr(context,reg_RBX);
840 *(sp-6)=*os_context_register_addr(context,reg_RDX);
841 *(sp-5)=*os_context_register_addr(context,reg_RCX);
842 *(sp-4)=*os_context_register_addr(context,reg_RAX);
843 *(sp-3)=*context_eflags_addr(context);
844 *(sp-2)=*os_context_register_addr(context,reg_RBP);
845 *(sp-1)=*os_context_pc_addr(context);
847 *os_context_register_addr(context,reg_RDI) =
848 (os_context_register_t)function; /* function */
849 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
850 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
852 struct thread *th=arch_os_get_current_thread();
853 build_fake_control_stack_frames(th,context);
856 #ifdef LISP_FEATURE_X86
857 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
858 *os_context_register_addr(context,reg_ECX) = 0;
859 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
861 *os_context_register_addr(context,reg_UESP) =
862 (os_context_register_t)(sp-15);
864 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
866 #elif defined(LISP_FEATURE_X86_64)
867 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
868 *os_context_register_addr(context,reg_RCX) = 0;
869 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
870 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
872 /* this much of the calling convention is common to all
874 *os_context_pc_addr(context) = (os_context_register_t)code;
875 *os_context_register_addr(context,reg_NARGS) = 0;
876 *os_context_register_addr(context,reg_LIP) = (os_context_register_t)code;
877 *os_context_register_addr(context,reg_CFP) =
878 (os_context_register_t)current_control_frame_pointer;
880 #ifdef ARCH_HAS_NPC_REGISTER
881 *os_context_npc_addr(context) =
882 4 + *os_context_pc_addr(context);
884 #ifdef LISP_FEATURE_SPARC
885 *os_context_register_addr(context,reg_CODE) =
886 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
890 #ifdef LISP_FEATURE_SB_THREAD
891 void interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
893 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
894 /* The order of interrupt execution is peculiar. If thread A
895 * interrupts thread B with I1, I2 and B for some reason receives
896 * I1 when FUN2 is already on the list, then it is FUN2 that gets
897 * to run first. But when FUN2 is run SIG_INTERRUPT_THREAD is
898 * enabled again and I2 hits pretty soon in FUN2 and run
899 * FUN1. This is of course just one scenario, and the order of
900 * thread interrupt execution is undefined. */
901 struct thread *th=arch_os_get_current_thread();
904 if (th->state != STATE_RUNNING)
905 lose("interrupt_thread_handler: thread %lu in wrong state: %d\n",
906 th->os_thread,fixnum_value(th->state));
907 get_spinlock(&th->interrupt_fun_lock,(long)th);
908 c=((struct cons *)native_pointer(th->interrupt_fun));
910 th->interrupt_fun=c->cdr;
911 release_spinlock(&th->interrupt_fun_lock);
913 lose("interrupt_thread_handler: NIL function\n");
914 arrange_return_to_lisp_function(context,function);
919 /* KLUDGE: Theoretically the approach we use for undefined alien
920 * variables should work for functions as well, but on PPC/Darwin
921 * we get bus error at bogus addresses instead, hence this workaround,
922 * that has the added benefit of automatically discriminating between
923 * functions and variables.
925 void undefined_alien_function() {
926 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
929 boolean handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
931 struct thread *th=arch_os_get_current_thread();
933 /* note the os_context hackery here. When the signal handler returns,
934 * it won't go back to what it was doing ... */
935 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
936 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
937 /* We hit the end of the control stack: disable guard page
938 * protection so the error handler has some headroom, protect the
939 * previous page so that we can catch returns from the guard page
941 protect_control_stack_guard_page(th,0);
942 protect_control_stack_return_guard_page(th,1);
944 arrange_return_to_lisp_function
945 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
948 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
949 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
950 /* We're returning from the guard page: reprotect it, and
951 * unprotect this one. This works even if we somehow missed
952 * the return-guard-page, and hit it on our way to new
953 * exhaustion instead. */
954 protect_control_stack_guard_page(th,1);
955 protect_control_stack_return_guard_page(th,0);
958 else if (addr >= undefined_alien_address &&
959 addr < undefined_alien_address + os_vm_page_size) {
960 arrange_return_to_lisp_function
961 (context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
967 #ifndef LISP_FEATURE_GENCGC
968 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
969 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
970 * whether the signal was due to treading on the mprotect()ed zone -
971 * and if so, arrange for a GC to happen. */
972 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
975 interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
977 os_context_t *context=(os_context_t *) void_context;
978 struct thread *th=arch_os_get_current_thread();
979 struct interrupt_data *data=
980 th ? th->interrupt_data : global_interrupt_data;
982 if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
983 struct thread *thread=arch_os_get_current_thread();
984 clear_auto_gc_trigger();
985 /* Don't flood the system with interrupts if the need to gc is
986 * already noted. This can happen for example when SUB-GC
987 * allocates or after a gc triggered in a WITHOUT-GCING. */
988 if (SymbolValue(GC_PENDING,thread) == NIL) {
989 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
990 if (arch_pseudo_atomic_atomic(context)) {
991 /* set things up so that GC happens when we finish
993 SetSymbolValue(GC_PENDING,T,thread);
994 arch_set_pseudo_atomic_interrupted(context);
996 interrupt_maybe_gc_int(signal,info,void_context);
999 SetSymbolValue(GC_PENDING,T,thread);
1009 /* this is also used by gencgc, in alloc() */
1011 interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
1013 os_context_t *context=(os_context_t *) void_context;
1014 struct thread *thread=arch_os_get_current_thread();
1016 check_blockables_blocked_or_lose();
1017 fake_foreign_function_call(context);
1019 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
1020 * which case we will be running with no gc trigger barrier
1021 * thing for a while. But it shouldn't be long until the end
1024 * FIXME: It would be good to protect the end of dynamic space
1025 * and signal a storage condition from there.
1028 /* Restore the signal mask from the interrupted context before
1029 * calling into Lisp if interrupts are enabled. Why not always?
1031 * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an
1032 * interrupt hits while in SUB-GC, it is deferred and the
1033 * os_context_sigmask of that interrupt is set to block further
1034 * deferrable interrupts (until the first one is
1035 * handled). Unfortunately, that context refers to this place and
1036 * when we return from here the signals will not be blocked.
1038 * A kludgy alternative is to propagate the sigmask change to the
1041 if(SymbolValue(INTERRUPTS_ENABLED,thread)!=NIL)
1042 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1043 #ifdef LISP_FEATURE_SB_THREAD
1046 sigaddset(&new,SIG_STOP_FOR_GC);
1047 thread_sigmask(SIG_UNBLOCK,&new,0);
1050 funcall0(SymbolFunction(SUB_GC));
1052 undo_fake_foreign_function_call(context);
1058 * noise to install handlers
1062 undoably_install_low_level_interrupt_handler (int signal,
1067 struct sigaction sa;
1068 struct thread *th=arch_os_get_current_thread();
1069 struct interrupt_data *data=
1070 th ? th->interrupt_data : global_interrupt_data;
1072 if (0 > signal || signal >= NSIG) {
1073 lose("bad signal number %d", signal);
1076 if (sigismember(&deferrable_sigset,signal))
1077 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1079 sa.sa_sigaction = handler;
1081 sigemptyset(&sa.sa_mask);
1082 sigaddset_blockable(&sa.sa_mask);
1083 sa.sa_flags = SA_SIGINFO | SA_RESTART;
1084 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1085 if((signal==SIG_MEMORY_FAULT)
1086 #ifdef SIG_INTERRUPT_THREAD
1087 || (signal==SIG_INTERRUPT_THREAD)
1090 sa.sa_flags|= SA_ONSTACK;
1093 sigaction(signal, &sa, NULL);
1094 data->interrupt_low_level_handlers[signal] =
1095 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1098 /* This is called from Lisp. */
1100 install_handler(int signal, void handler(int, siginfo_t*, void*))
1102 struct sigaction sa;
1104 union interrupt_handler oldhandler;
1105 struct thread *th=arch_os_get_current_thread();
1106 struct interrupt_data *data=
1107 th ? th->interrupt_data : global_interrupt_data;
1109 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1112 sigaddset(&new, signal);
1113 thread_sigmask(SIG_BLOCK, &new, &old);
1115 FSHOW((stderr, "/data->interrupt_low_level_handlers[signal]=%x\n",
1116 (unsigned int)data->interrupt_low_level_handlers[signal]));
1117 if (data->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 sigemptyset(&sa.sa_mask);
1128 sigaddset_blockable(&sa.sa_mask);
1129 sa.sa_flags = SA_SIGINFO | SA_RESTART;
1130 sigaction(signal, &sa, NULL);
1133 oldhandler = data->interrupt_handlers[signal];
1134 data->interrupt_handlers[signal].c = handler;
1136 thread_sigmask(SIG_SETMASK, &old, 0);
1138 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1140 return (unsigned long)oldhandler.lisp;
1147 SHOW("entering interrupt_init()");
1148 sigemptyset(&deferrable_sigset);
1149 sigemptyset(&blockable_sigset);
1150 sigaddset_deferrable(&deferrable_sigset);
1151 sigaddset_blockable(&blockable_sigset);
1153 global_interrupt_data=calloc(sizeof(struct interrupt_data), 1);
1155 /* Set up high level handler information. */
1156 for (i = 0; i < NSIG; i++) {
1157 global_interrupt_data->interrupt_handlers[i].c =
1158 /* (The cast here blasts away the distinction between
1159 * SA_SIGACTION-style three-argument handlers and
1160 * signal(..)-style one-argument handlers, which is OK
1161 * because it works to call the 1-argument form where the
1162 * 3-argument form is expected.) */
1163 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1166 SHOW("returning from interrupt_init()");