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;
113 inline static void check_blockables_blocked_or_lose()
115 /* Get the current sigmask, by blocking the empty set. */
116 sigset_t empty,current;
119 thread_sigmask(SIG_BLOCK, &empty, ¤t);
120 for(i=0;i<NSIG;i++) {
121 if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i))
122 lose("blockable signal %d not blocked",i);
126 inline static void check_interrupts_enabled_or_lose(os_context_t *context)
128 struct thread *thread=arch_os_get_current_thread();
129 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
130 lose("interrupts not enabled");
132 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
133 (!foreign_function_call_active) &&
135 arch_pseudo_atomic_atomic(context))
136 lose ("in pseudo atomic section");
139 /* When we catch an internal error, should we pass it back to Lisp to
140 * be handled in a high-level way? (Early in cold init, the answer is
141 * 'no', because Lisp is still too brain-dead to handle anything.
142 * After sufficient initialization has been completed, the answer
144 boolean internal_errors_enabled = 0;
146 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*);
147 union interrupt_handler interrupt_handlers[NSIG];
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(void)
157 thread_sigmask(SIG_SETMASK,&new,0);
160 void block_blockable_signals(void)
163 sigcopyset(&block, &blockable_sigset);
164 thread_sigmask(SIG_BLOCK, &block, 0);
169 * utility routines used by various signal handlers
173 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
175 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
179 /* Build a fake stack frame or frames */
181 current_control_frame_pointer =
182 (lispobj *)(unsigned long)
183 (*os_context_register_addr(context, reg_CSP));
184 if ((lispobj *)(unsigned long)
185 (*os_context_register_addr(context, reg_CFP))
186 == current_control_frame_pointer) {
187 /* There is a small window during call where the callee's
188 * frame isn't built yet. */
189 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
190 == FUN_POINTER_LOWTAG) {
191 /* We have called, but not built the new frame, so
192 * build it for them. */
193 current_control_frame_pointer[0] =
194 *os_context_register_addr(context, reg_OCFP);
195 current_control_frame_pointer[1] =
196 *os_context_register_addr(context, reg_LRA);
197 current_control_frame_pointer += 8;
198 /* Build our frame on top of it. */
199 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
202 /* We haven't yet called, build our frame as if the
203 * partial frame wasn't there. */
204 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
207 /* We can't tell whether we are still in the caller if it had to
208 * allocate a stack frame due to stack arguments. */
209 /* This observation provoked some past CMUCL maintainer to ask
210 * "Can anything strange happen during return?" */
213 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
216 current_control_stack_pointer = current_control_frame_pointer + 8;
218 current_control_frame_pointer[0] = oldcont;
219 current_control_frame_pointer[1] = NIL;
220 current_control_frame_pointer[2] =
221 (lispobj)(*os_context_register_addr(context, reg_CODE));
226 fake_foreign_function_call(os_context_t *context)
229 struct thread *thread=arch_os_get_current_thread();
231 /* context_index incrementing must not be interrupted */
232 check_blockables_blocked_or_lose();
234 /* Get current Lisp state from context. */
236 dynamic_space_free_pointer =
237 (lispobj *)(unsigned long)
238 (*os_context_register_addr(context, reg_ALLOC));
239 #if defined(LISP_FEATURE_ALPHA)
240 if ((long)dynamic_space_free_pointer & 1) {
241 lose("dead in fake_foreign_function_call, context = %x", context);
246 current_binding_stack_pointer =
247 (lispobj *)(unsigned long)
248 (*os_context_register_addr(context, reg_BSP));
251 build_fake_control_stack_frames(thread,context);
253 /* Do dynamic binding of the active interrupt context index
254 * and save the context in the context array. */
256 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
258 if (context_index >= MAX_INTERRUPTS) {
259 lose("maximum interrupt nesting depth (%d) exceeded", MAX_INTERRUPTS);
262 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
263 make_fixnum(context_index + 1),thread);
265 thread->interrupt_contexts[context_index] = context;
267 /* no longer in Lisp now */
268 foreign_function_call_active = 1;
271 /* blocks all blockable signals. If you are calling from a signal handler,
272 * the usual signal mask will be restored from the context when the handler
273 * finishes. Otherwise, be careful */
276 undo_fake_foreign_function_call(os_context_t *context)
278 struct thread *thread=arch_os_get_current_thread();
279 /* Block all blockable signals. */
280 block_blockable_signals();
282 /* going back into Lisp */
283 foreign_function_call_active = 0;
285 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
289 /* Put the dynamic space free pointer back into the context. */
290 *os_context_register_addr(context, reg_ALLOC) =
291 (unsigned long) dynamic_space_free_pointer;
295 /* a handler for the signal caused by execution of a trap opcode
296 * signalling an internal error */
298 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
303 fake_foreign_function_call(context);
305 if (!internal_errors_enabled) {
306 describe_internal_error(context);
307 /* There's no good way to recover from an internal error
308 * before the Lisp error handling mechanism is set up. */
309 lose("internal error too early in init, can't recover");
312 /* Allocate the SAP object while the interrupts are still
314 context_sap = alloc_sap(context);
316 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
318 SHOW("in interrupt_internal_error");
320 /* Display some rudimentary debugging information about the
321 * error, so that even if the Lisp error handler gets badly
322 * confused, we have a chance to determine what's going on. */
323 describe_internal_error(context);
325 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
326 continuable ? T : NIL);
328 undo_fake_foreign_function_call(context); /* blocks signals again */
330 arch_skip_instruction(context);
334 interrupt_handle_pending(os_context_t *context)
336 struct thread *thread;
337 struct interrupt_data *data;
339 check_blockables_blocked_or_lose();
341 thread=arch_os_get_current_thread();
342 data=thread->interrupt_data;
344 if (SymbolValue(GC_INHIBIT,thread)==NIL) {
345 #ifdef LISP_FEATURE_SB_THREAD
346 if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) {
347 /* another thread has already initiated a gc, this attempt
348 * might as well be cancelled */
349 SetSymbolValue(GC_PENDING,NIL,thread);
350 SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread);
351 sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context);
354 if (SymbolValue(GC_PENDING,thread) != NIL) {
355 /* GC_PENDING is cleared in SUB-GC, or if another thread
356 * is doing a gc already we will get a SIG_STOP_FOR_GC and
357 * that will clear it. */
358 interrupt_maybe_gc_int(0,NULL,context);
360 check_blockables_blocked_or_lose();
363 /* we may be here only to do the gc stuff, if interrupts are
364 * enabled run the pending handler */
365 if (!((SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) ||
367 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
368 (!foreign_function_call_active) &&
370 arch_pseudo_atomic_atomic(context)))) {
372 /* There may be no pending handler, because it was only a gc
373 * that had to be executed or because pseudo atomic triggered
374 * twice for a single interrupt. For the interested reader,
375 * that may happen if an interrupt hits after the interrupted
376 * flag is cleared but before pseduo-atomic is set and a
377 * pseudo atomic is interrupted in that interrupt. */
378 if (data->pending_handler) {
380 /* If we're here as the result of a pseudo-atomic as opposed
381 * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already
382 * NIL, because maybe_defer_handler sets
383 * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/
384 SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
386 /* restore the saved signal mask from the original signal (the
387 * one that interrupted us during the critical section) into the
388 * os_context for the signal we're currently in the handler for.
389 * This should ensure that when we return from the handler the
390 * blocked signals are unblocked */
391 sigcopyset(os_context_sigmask_addr(context), &data->pending_mask);
393 sigemptyset(&data->pending_mask);
394 /* This will break on sparc linux: the deferred handler really wants
395 * to be called with a void_context */
396 run_deferred_handler(data,(void *)context);
402 * the two main signal handlers:
403 * interrupt_handle_now(..)
404 * maybe_now_maybe_later(..)
406 * to which we have added interrupt_handle_now_handler(..). Why?
407 * Well, mostly because the SPARC/Linux platform doesn't quite do
408 * signals the way we want them done. The third argument in the
409 * handler isn't filled in by the kernel properly, so we fix it up
410 * ourselves in the arch_os_get_context(..) function; however, we only
411 * want to do this when we first hit the handler, and not when
412 * interrupt_handle_now(..) is being called from some other handler
413 * (when the fixup will already have been done). -- CSR, 2002-07-23
417 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
419 os_context_t *context = (os_context_t*)void_context;
420 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
421 boolean were_in_lisp;
423 union interrupt_handler handler;
424 check_blockables_blocked_or_lose();
425 if (sigismember(&deferrable_sigset,signal))
426 check_interrupts_enabled_or_lose(context);
428 #ifdef LISP_FEATURE_LINUX
429 /* Under Linux on some architectures, we appear to have to restore
430 the FPU control word from the context, as after the signal is
431 delivered we appear to have a null FPU control word. */
432 os_restore_fp_control(context);
434 handler = interrupt_handlers[signal];
436 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
440 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
441 were_in_lisp = !foreign_function_call_active;
445 fake_foreign_function_call(context);
448 FSHOW_SIGNAL((stderr,
449 "/entering interrupt_handle_now(%d, info, context)\n",
452 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
454 /* This can happen if someone tries to ignore or default one
455 * of the signals we need for runtime support, and the runtime
456 * support decides to pass on it. */
457 lose("no handler for signal %d in interrupt_handle_now(..)", signal);
459 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
460 /* Once we've decided what to do about contexts in a
461 * return-elsewhere world (the original context will no longer
462 * be available; should we copy it or was nobody using it anyway?)
463 * then we should convert this to return-elsewhere */
465 /* CMUCL comment said "Allocate the SAPs while the interrupts
466 * are still disabled.". I (dan, 2003.08.21) assume this is
467 * because we're not in pseudoatomic and allocation shouldn't
468 * be interrupted. In which case it's no longer an issue as
469 * all our allocation from C now goes through a PA wrapper,
470 * but still, doesn't hurt.
472 * Yeah, but non-gencgc platforms that don't really wrap
473 * allocation in PA. MG - 2005-08-29 */
475 lispobj info_sap,context_sap = alloc_sap(context);
476 info_sap = alloc_sap(info);
477 /* Leave deferrable signals blocked, the handler itself will
478 * allow signals again when it sees fit. */
479 #ifdef LISP_FEATURE_SB_THREAD
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);
699 FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread));
700 if(thread->state!=STATE_RUNNING) {
701 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
702 fixnum_value(thread->state));
705 undo_fake_foreign_function_call(context);
711 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
713 os_context_t *context = arch_os_get_context(&void_context);
714 interrupt_handle_now(signal, info, context);
715 #ifdef LISP_FEATURE_DARWIN
716 DARWIN_FIX_CONTEXT(context);
721 * stuff to detect and handle hitting the GC trigger
724 #ifndef LISP_FEATURE_GENCGC
725 /* since GENCGC has its own way to record trigger */
727 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
729 if (current_auto_gc_trigger == NULL)
732 void *badaddr=arch_get_bad_addr(signal,info,context);
733 return (badaddr >= (void *)current_auto_gc_trigger &&
734 badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE));
739 /* manipulate the signal context and stack such that when the handler
740 * returns, it will call function instead of whatever it was doing
744 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
745 int *context_eflags_addr(os_context_t *context);
748 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
749 extern void post_signal_tramp(void);
750 void arrange_return_to_lisp_function(os_context_t *context, lispobj function)
752 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
753 void * fun=native_pointer(function);
754 void *code = &(((struct simple_fun *) fun)->code);
757 /* Build a stack frame showing `interrupted' so that the
758 * user's backtrace makes (as much) sense (as usual) */
760 /* FIXME: what about restoring fp state? */
761 /* FIXME: what about restoring errno? */
762 #ifdef LISP_FEATURE_X86
763 /* Suppose the existence of some function that saved all
764 * registers, called call_into_lisp, then restored GP registers and
765 * returned. It would look something like this:
773 pushl {address of function to call}
774 call 0x8058db0 <call_into_lisp>
781 * What we do here is set up the stack that call_into_lisp would
782 * expect to see if it had been called by this code, and frob the
783 * signal context so that signal return goes directly to call_into_lisp,
784 * and when that function (and the lisp function it invoked) returns,
785 * it returns to the second half of this imaginary function which
786 * restores all registers and returns to C
788 * For this to work, the latter part of the imaginary function
789 * must obviously exist in reality. That would be post_signal_tramp
792 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
794 /* return address for call_into_lisp: */
795 *(sp-15) = (u32)post_signal_tramp;
796 *(sp-14) = function; /* args for call_into_lisp : function*/
797 *(sp-13) = 0; /* arg array */
798 *(sp-12) = 0; /* no. args */
799 /* this order matches that used in POPAD */
800 *(sp-11)=*os_context_register_addr(context,reg_EDI);
801 *(sp-10)=*os_context_register_addr(context,reg_ESI);
803 *(sp-9)=*os_context_register_addr(context,reg_ESP)-8;
804 /* POPAD ignores the value of ESP: */
806 *(sp-7)=*os_context_register_addr(context,reg_EBX);
808 *(sp-6)=*os_context_register_addr(context,reg_EDX);
809 *(sp-5)=*os_context_register_addr(context,reg_ECX);
810 *(sp-4)=*os_context_register_addr(context,reg_EAX);
811 *(sp-3)=*context_eflags_addr(context);
812 *(sp-2)=*os_context_register_addr(context,reg_EBP);
813 *(sp-1)=*os_context_pc_addr(context);
815 #elif defined(LISP_FEATURE_X86_64)
816 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
817 /* return address for call_into_lisp: */
818 *(sp-18) = (u64)post_signal_tramp;
820 *(sp-17)=*os_context_register_addr(context,reg_R15);
821 *(sp-16)=*os_context_register_addr(context,reg_R14);
822 *(sp-15)=*os_context_register_addr(context,reg_R13);
823 *(sp-14)=*os_context_register_addr(context,reg_R12);
824 *(sp-13)=*os_context_register_addr(context,reg_R11);
825 *(sp-12)=*os_context_register_addr(context,reg_R10);
826 *(sp-11)=*os_context_register_addr(context,reg_R9);
827 *(sp-10)=*os_context_register_addr(context,reg_R8);
828 *(sp-9)=*os_context_register_addr(context,reg_RDI);
829 *(sp-8)=*os_context_register_addr(context,reg_RSI);
830 /* skip RBP and RSP */
831 *(sp-7)=*os_context_register_addr(context,reg_RBX);
832 *(sp-6)=*os_context_register_addr(context,reg_RDX);
833 *(sp-5)=*os_context_register_addr(context,reg_RCX);
834 *(sp-4)=*os_context_register_addr(context,reg_RAX);
835 *(sp-3)=*context_eflags_addr(context);
836 *(sp-2)=*os_context_register_addr(context,reg_RBP);
837 *(sp-1)=*os_context_pc_addr(context);
839 *os_context_register_addr(context,reg_RDI) =
840 (os_context_register_t)function; /* function */
841 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
842 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
844 struct thread *th=arch_os_get_current_thread();
845 build_fake_control_stack_frames(th,context);
848 #ifdef LISP_FEATURE_X86
849 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
850 *os_context_register_addr(context,reg_ECX) = 0;
851 *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2);
853 *os_context_register_addr(context,reg_UESP) =
854 (os_context_register_t)(sp-15);
856 *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15);
858 #elif defined(LISP_FEATURE_X86_64)
859 *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp;
860 *os_context_register_addr(context,reg_RCX) = 0;
861 *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2);
862 *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18);
864 /* this much of the calling convention is common to all
866 *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code;
867 *os_context_register_addr(context,reg_NARGS) = 0;
868 *os_context_register_addr(context,reg_LIP) =
869 (os_context_register_t)(unsigned long)code;
870 *os_context_register_addr(context,reg_CFP) =
871 (os_context_register_t)(unsigned long)current_control_frame_pointer;
873 #ifdef ARCH_HAS_NPC_REGISTER
874 *os_context_npc_addr(context) =
875 4 + *os_context_pc_addr(context);
877 #ifdef LISP_FEATURE_SPARC
878 *os_context_register_addr(context,reg_CODE) =
879 (os_context_register_t)(fun + FUN_POINTER_LOWTAG);
883 #ifdef LISP_FEATURE_SB_THREAD
885 /* FIXME: this function can go away when all lisp handlers are invoked
886 * via arrange_return_to_lisp_function. */
887 void interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
889 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
890 /* let the handler enable interrupts again when it sees fit */
891 sigaddset_deferrable(os_context_sigmask_addr(context));
892 arrange_return_to_lisp_function(context, SymbolFunction(RUN_INTERRUPTION));
897 /* KLUDGE: Theoretically the approach we use for undefined alien
898 * variables should work for functions as well, but on PPC/Darwin
899 * we get bus error at bogus addresses instead, hence this workaround,
900 * that has the added benefit of automatically discriminating between
901 * functions and variables.
903 void undefined_alien_function() {
904 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
907 boolean handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr)
909 struct thread *th=arch_os_get_current_thread();
911 /* note the os_context hackery here. When the signal handler returns,
912 * it won't go back to what it was doing ... */
913 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
914 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
915 /* We hit the end of the control stack: disable guard page
916 * protection so the error handler has some headroom, protect the
917 * previous page so that we can catch returns from the guard page
919 protect_control_stack_guard_page(0);
920 protect_control_stack_return_guard_page(1);
922 arrange_return_to_lisp_function
923 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
926 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
927 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
928 /* We're returning from the guard page: reprotect it, and
929 * unprotect this one. This works even if we somehow missed
930 * the return-guard-page, and hit it on our way to new
931 * exhaustion instead. */
932 protect_control_stack_guard_page(1);
933 protect_control_stack_return_guard_page(0);
936 else if (addr >= undefined_alien_address &&
937 addr < undefined_alien_address + os_vm_page_size) {
938 arrange_return_to_lisp_function
939 (context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
945 #ifndef LISP_FEATURE_GENCGC
946 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
947 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
948 * whether the signal was due to treading on the mprotect()ed zone -
949 * and if so, arrange for a GC to happen. */
950 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
953 interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
955 os_context_t *context=(os_context_t *) void_context;
957 if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
958 struct thread *thread=arch_os_get_current_thread();
959 clear_auto_gc_trigger();
960 /* Don't flood the system with interrupts if the need to gc is
961 * already noted. This can happen for example when SUB-GC
962 * allocates or after a gc triggered in a WITHOUT-GCING. */
963 if (SymbolValue(GC_PENDING,thread) == NIL) {
964 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
965 if (arch_pseudo_atomic_atomic(context)) {
966 /* set things up so that GC happens when we finish
968 SetSymbolValue(GC_PENDING,T,thread);
969 arch_set_pseudo_atomic_interrupted(context);
971 interrupt_maybe_gc_int(signal,info,void_context);
974 SetSymbolValue(GC_PENDING,T,thread);
984 /* this is also used by gencgc, in alloc() */
986 interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
988 os_context_t *context=(os_context_t *) void_context;
989 struct thread *thread=arch_os_get_current_thread();
991 fake_foreign_function_call(context);
993 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
994 * which case we will be running with no gc trigger barrier
995 * thing for a while. But it shouldn't be long until the end
998 * FIXME: It would be good to protect the end of dynamic space
999 * and signal a storage condition from there.
1002 /* Restore the signal mask from the interrupted context before
1003 * calling into Lisp if interrupts are enabled. Why not always?
1005 * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an
1006 * interrupt hits while in SUB-GC, it is deferred and the
1007 * os_context_sigmask of that interrupt is set to block further
1008 * deferrable interrupts (until the first one is
1009 * handled). Unfortunately, that context refers to this place and
1010 * when we return from here the signals will not be blocked.
1012 * A kludgy alternative is to propagate the sigmask change to the
1015 if(SymbolValue(INTERRUPTS_ENABLED,thread)!=NIL)
1016 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
1017 #ifdef LISP_FEATURE_SB_THREAD
1020 sigaddset(&new,SIG_STOP_FOR_GC);
1021 thread_sigmask(SIG_UNBLOCK,&new,0);
1024 funcall0(SymbolFunction(SUB_GC));
1026 undo_fake_foreign_function_call(context);
1032 * noise to install handlers
1036 undoably_install_low_level_interrupt_handler (int signal,
1041 struct sigaction sa;
1043 if (0 > signal || signal >= NSIG) {
1044 lose("bad signal number %d", signal);
1047 if (sigismember(&deferrable_sigset,signal))
1048 sa.sa_sigaction = low_level_maybe_now_maybe_later;
1050 sa.sa_sigaction = handler;
1052 sigcopyset(&sa.sa_mask, &blockable_sigset);
1053 sa.sa_flags = SA_SIGINFO | SA_RESTART;
1054 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1055 if((signal==SIG_MEMORY_FAULT)
1056 #ifdef SIG_INTERRUPT_THREAD
1057 || (signal==SIG_INTERRUPT_THREAD)
1060 sa.sa_flags |= SA_ONSTACK;
1063 sigaction(signal, &sa, NULL);
1064 interrupt_low_level_handlers[signal] =
1065 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
1068 /* This is called from Lisp. */
1070 install_handler(int signal, void handler(int, siginfo_t*, void*))
1072 struct sigaction sa;
1074 union interrupt_handler oldhandler;
1076 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
1079 sigaddset(&new, signal);
1080 thread_sigmask(SIG_BLOCK, &new, &old);
1082 FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n",
1083 (unsigned int)interrupt_low_level_handlers[signal]));
1084 if (interrupt_low_level_handlers[signal]==0) {
1085 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
1086 ARE_SAME_HANDLER(handler, SIG_IGN)) {
1087 sa.sa_sigaction = handler;
1088 } else if (sigismember(&deferrable_sigset, signal)) {
1089 sa.sa_sigaction = maybe_now_maybe_later;
1091 sa.sa_sigaction = interrupt_handle_now_handler;
1094 sigcopyset(&sa.sa_mask, &blockable_sigset);
1095 sa.sa_flags = SA_SIGINFO | SA_RESTART;
1096 sigaction(signal, &sa, NULL);
1099 oldhandler = interrupt_handlers[signal];
1100 interrupt_handlers[signal].c = handler;
1102 thread_sigmask(SIG_SETMASK, &old, 0);
1104 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
1106 return (unsigned long)oldhandler.lisp;
1113 SHOW("entering interrupt_init()");
1114 sigemptyset(&deferrable_sigset);
1115 sigemptyset(&blockable_sigset);
1116 sigaddset_deferrable(&deferrable_sigset);
1117 sigaddset_blockable(&blockable_sigset);
1119 /* Set up high level handler information. */
1120 for (i = 0; i < NSIG; i++) {
1121 interrupt_handlers[i].c =
1122 /* (The cast here blasts away the distinction between
1123 * SA_SIGACTION-style three-argument handlers and
1124 * signal(..)-style one-argument handlers, which is OK
1125 * because it works to call the 1-argument form where the
1126 * 3-argument form is expected.) */
1127 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1130 SHOW("returning from interrupt_init()");