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.
19 #ifdef mach /* KLUDGE: #ifdef on lowercase symbols? Ick. -- WHN 19990904 */
29 #include "interrupt.h"
39 void sigaddset_blockable(sigset_t *s)
43 sigaddset(s, SIGQUIT);
44 sigaddset(s, SIGPIPE);
45 sigaddset(s, SIGALRM);
47 sigaddset(s, SIGTSTP);
48 sigaddset(s, SIGCHLD);
50 sigaddset(s, SIGXCPU);
51 sigaddset(s, SIGXFSZ);
52 sigaddset(s, SIGVTALRM);
53 sigaddset(s, SIGPROF);
54 sigaddset(s, SIGWINCH);
55 sigaddset(s, SIGUSR1);
56 sigaddset(s, SIGUSR2);
59 /* When we catch an internal error, should we pass it back to Lisp to
60 * be handled in a high-level way? (Early in cold init, the answer is
61 * 'no', because Lisp is still too brain-dead to handle anything.
62 * After sufficient initialization has been completed, the answer
64 boolean internal_errors_enabled = 0;
66 os_context_t *lisp_interrupt_contexts[MAX_INTERRUPTS];
68 /* As far as I can tell, what's going on here is:
70 * In the case of most signals, when Lisp asks us to handle the
71 * signal, the outermost handler (the one actually passed to UNIX) is
72 * either interrupt_handle_now(..) or interrupt_handle_later(..).
73 * In that case, the Lisp-level handler is stored in interrupt_handlers[..]
74 * and interrupt_low_level_handlers[..] is cleared.
76 * However, some signals need special handling, e.g. the SIGSEGV (for
77 * Linux) or SIGBUS (for FreeBSD) used by the garbage collector to
78 * detect violations of write protection, because some cases of such
79 * signals are handled at C level and never passed on to Lisp. For
80 * such signals, we still store any Lisp-level handler in
81 * interrupt_handlers[..], but for the outermost handle we use the
82 * value from interrupt_low_level_handlers[..], instead of the
83 * ordinary interrupt_handle_now(..) or interrupt_handle_later(..).
86 void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*) = {0};
87 union interrupt_handler interrupt_handlers[NSIG];
89 /* signal number, siginfo_t, and old mask information for pending signal
91 * pending_signal=0 when there is no pending signal. */
92 static int pending_signal = 0;
93 static siginfo_t pending_info;
94 static sigset_t pending_mask;
96 static boolean maybe_gc_pending = 0;
99 * utility routines used by various signal handlers
103 fake_foreign_function_call(os_context_t *context)
110 /* Get current Lisp state from context. */
112 dynamic_space_free_pointer =
113 (lispobj *)(*os_context_register_addr(context, reg_ALLOC));
115 if ((long)dynamic_space_free_pointer & 1) {
116 lose("dead in fake_foreign_function_call, context = %x", context);
121 current_binding_stack_pointer =
122 (lispobj *)(*os_context_register_addr(context, reg_BSP));
126 /* Build a fake stack frame. */
127 current_control_frame_pointer =
128 (lispobj *)(*os_context_register_addr(context, reg_CSP));
129 if ((lispobj *)(*os_context_register_addr(context, reg_CFP))
130 == current_control_frame_pointer) {
131 /* There is a small window during call where the callee's
132 * frame isn't built yet. */
133 if (LowtagOf(*os_context_register_addr(context, reg_CODE))
134 == type_FunctionPointer) {
135 /* We have called, but not built the new frame, so
136 * build it for them. */
137 current_control_frame_pointer[0] =
138 *os_context_register_addr(context, reg_OCFP);
139 current_control_frame_pointer[1] =
140 *os_context_register_addr(context, reg_LRA);
141 current_control_frame_pointer += 8;
142 /* Build our frame on top of it. */
143 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
146 /* We haven't yet called, build our frame as if the
147 * partial frame wasn't there. */
148 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
151 /* ### We can't tell if we are still in the caller if it had to
152 * reg_ALLOCate the stack frame due to stack arguments. */
153 /* ### Can anything strange happen during return? */
156 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
158 current_control_stack_pointer = current_control_frame_pointer + 8;
160 current_control_frame_pointer[0] = oldcont;
161 current_control_frame_pointer[1] = NIL;
162 current_control_frame_pointer[2] =
163 (lispobj)(*os_context_register_addr(context, reg_CODE));
166 /* Do dynamic binding of the active interrupt context index
167 * and save the context in the context array. */
168 context_index = SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX)>>2;
169 /* FIXME: Ick! Why use abstract "make_fixnum" in some places if
170 * you're going to convert from fixnum by bare >>2 in other
171 * places? Use fixnum_value(..) here, and look for other places
172 * which do bare >> and << for fixnum_value and make_fixnum. */
174 if (context_index >= MAX_INTERRUPTS) {
175 lose("maximum interrupt nesting depth (%d) exceeded",
179 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
180 make_fixnum(context_index + 1));
182 lisp_interrupt_contexts[context_index] = context;
184 /* no longer in Lisp now */
185 foreign_function_call_active = 1;
189 undo_fake_foreign_function_call(os_context_t *context)
191 /* Block all blockable signals. */
194 sigaddset_blockable(&block);
195 sigprocmask(SIG_BLOCK, &block, 0);
197 /* going back into Lisp */
198 foreign_function_call_active = 0;
200 /* Undo dynamic binding. */
201 /* ### Do I really need to unbind_to_here()? */
202 /* FIXME: Is this to undo the binding of
203 * FREE_INTERRUPT_CONTEXT_INDEX? If so, we should say so. And
204 * perhaps yes, unbind_to_here() really would be clearer and less
209 /* Put the dynamic space free pointer back into the context. */
210 *os_context_register_addr(context, reg_ALLOC) =
211 (unsigned long) dynamic_space_free_pointer;
215 /* a handler for the signal caused by execution of a trap opcode
216 * signalling an internal error */
218 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
223 fake_foreign_function_call(context);
225 /* Allocate the SAP object while the interrupts are still
227 if (internal_errors_enabled) {
228 context_sap = alloc_sap(context);
231 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
233 if (internal_errors_enabled) {
234 SHOW("in interrupt_internal_error");
236 /* Display some rudimentary debugging information about the
237 * error, so that even if the Lisp error handler gets badly
238 * confused, we have a chance to determine what's going on. */
239 describe_internal_error(context);
241 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
242 continuable ? T : NIL);
244 describe_internal_error(context);
245 /* There's no good way to recover from an internal error
246 * before the Lisp error handling mechanism is set up. */
247 lose("internal error too early in init, can't recover");
249 undo_fake_foreign_function_call(context);
251 arch_skip_instruction(context);
256 interrupt_handle_pending(os_context_t *context)
258 boolean were_in_lisp = !foreign_function_call_active;
260 SetSymbolValue(INTERRUPT_PENDING, NIL);
262 if (maybe_gc_pending) {
263 maybe_gc_pending = 0;
268 fake_foreign_function_call(context);
270 funcall0(SymbolFunction(MAYBE_GC));
275 undo_fake_foreign_function_call(context);
279 /* FIXME: How come we unconditionally copy from pending_mask into
280 * the context, and then test whether pending_signal is set? If
281 * pending_signal wasn't set, how could pending_mask be valid? */
282 memcpy(os_context_sigmask_addr(context), &pending_mask, sizeof(sigset_t));
283 sigemptyset(&pending_mask);
284 if (pending_signal) {
285 int signal = pending_signal;
287 memcpy(&info, &pending_info, sizeof(siginfo_t));
289 interrupt_handle_now(signal, &info, context);
294 * the two main signal handlers:
295 * interrupt_handle_now(..)
296 * maybe_now_maybe_later(..)
300 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
302 os_context_t *context = (os_context_t*)void_context;
304 union interrupt_handler handler;
307 SET_FPU_CONTROL_WORD(context->__fpregs_mem.cw);
310 handler = interrupt_handlers[signal];
312 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
316 were_in_lisp = !foreign_function_call_active;
321 fake_foreign_function_call(context);
325 FSHOW((stderr, "in interrupt_handle_now(%d, info, context)\n", signal));
328 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
330 /* This can happen if someone tries to ignore or default one
331 * of the signals we need for runtime support, and the runtime
332 * support decides to pass on it. */
333 lose("no handler for signal %d in interrupt_handle_now(..)", signal);
335 } else if (LowtagOf(handler.lisp) == type_FunctionPointer) {
337 /* Allocate the SAPs while the interrupts are still disabled.
338 * (FIXME: Why? This is the way it was done in CMU CL, and it
339 * even had the comment noting that this is the way it was
340 * done, but no motivation..) */
341 lispobj context_sap = alloc_sap(context);
342 lispobj info_sap = alloc_sap(info);
344 /* Allow signals again. */
345 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
348 SHOW("calling Lisp-level handler");
351 funcall3(handler.lisp,
358 SHOW("calling C-level handler");
361 /* Allow signals again. */
362 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
364 (*handler.c)(signal, info, void_context);
371 undo_fake_foreign_function_call(context);
376 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
378 os_context_t *context = (os_context_t*)void_context;
380 /* FIXME: See Debian cmucl 2.4.17, and mail from DTC on the CMU CL
381 * mailing list 23 Oct 1999, for changes in FPU handling at
382 * interrupt time which should be ported into SBCL.
384 * (Is this related to the way that it seems that if we do decide
385 * to handle the interrupt later, we've now screwed up the FPU
388 SET_FPU_CONTROL_WORD(context->__fpregs_mem.cw);
391 if (SymbolValue(INTERRUPTS_ENABLED) == NIL) {
393 /* FIXME: This code is exactly the same as the code in the
394 * other leg of the if(..), and should be factored out into
395 * a shared function. */
396 pending_signal = signal;
397 memcpy(&pending_info, info, sizeof(siginfo_t));
398 memcpy(&pending_mask,
399 os_context_sigmask_addr(context),
401 sigaddset_blockable(os_context_sigmask_addr(context));
403 SetSymbolValue(INTERRUPT_PENDING, T);
407 (!foreign_function_call_active) &&
409 arch_pseudo_atomic_atomic(context)) {
411 /* FIXME: It would probably be good to replace these bare
412 * memcpy(..) calls with calls to cpy_siginfo_t and
413 * cpy_sigset_t, so that we only have to get the sizeof
414 * expressions right in one place, and after that static type
415 * checking takes over. */
416 pending_signal = signal;
417 memcpy(&pending_info, info, sizeof(siginfo_t));
418 memcpy(&pending_mask,
419 os_context_sigmask_addr(context),
421 sigaddset_blockable(os_context_sigmask_addr(context));
423 arch_set_pseudo_atomic_interrupted(context);
426 interrupt_handle_now(signal, info, context);
431 * stuff to detect and handle hitting the GC trigger
434 #ifndef INTERNAL_GC_TRIGGER
436 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
438 if (current_auto_gc_trigger == NULL)
441 lispobj *badaddr=(lispobj *)arch_get_bad_addr(signal,
445 return (badaddr >= current_auto_gc_trigger &&
446 badaddr < DYNAMIC_SPACE_START + DYNAMIC_SPACE_SIZE);
453 interrupt_maybe_gc(int signal, siginfo_t *info, os_context_t *context)
455 if (!foreign_function_call_active
456 #ifndef INTERNAL_GC_TRIGGER
457 && gc_trigger_hit(signal, info, context)
460 #ifndef INTERNAL_GC_TRIGGER
461 clear_auto_gc_trigger();
464 if (arch_pseudo_atomic_atomic(context)) {
465 maybe_gc_pending = 1;
466 if (pending_signal == 0) {
467 /* FIXME: This copy-pending_mask-then-sigaddset_blockable
468 * idiom occurs over and over. It should be factored out
469 * into a function with a descriptive name. */
470 memcpy(&pending_mask,
471 os_context_sigmask_addr(context),
473 sigaddset_blockable(os_context_sigmask_addr(context));
475 arch_set_pseudo_atomic_interrupted(context);
478 fake_foreign_function_call(context);
479 funcall0(SymbolFunction(MAYBE_GC));
480 undo_fake_foreign_function_call(context);
491 * noise to install handlers
494 /* Install a special low-level handler for signal; or if handler is
495 * SIG_DFL, remove any special handling for signal. */
497 interrupt_install_low_level_handler (int signal,
498 void handler(int, siginfo_t*, void*))
502 sa.sa_sigaction = handler;
503 sigemptyset(&sa.sa_mask);
504 sigaddset_blockable(&sa.sa_mask);
505 sa.sa_flags = SA_SIGINFO | SA_RESTART;
507 sigaction(signal, &sa, NULL);
508 interrupt_low_level_handlers[signal] =
509 (ARE_SAME_HANDLER(handler,SIG_DFL) ? 0 : handler);
512 /* This is called from Lisp. */
514 install_handler(int signal, void handler(int, siginfo_t*, void*))
518 union interrupt_handler oldhandler;
520 FSHOW((stderr, "entering POSIX install_handler(%d, ..)\n", signal));
523 sigaddset(&new, signal);
524 sigprocmask(SIG_BLOCK, &new, &old);
527 sigaddset_blockable(&new);
529 FSHOW((stderr, "interrupt_low_level_handlers[signal]=%d\n",
530 interrupt_low_level_handlers[signal]));
531 if (interrupt_low_level_handlers[signal]==0) {
532 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
533 ARE_SAME_HANDLER(handler, SIG_IGN)) {
534 sa.sa_sigaction = handler;
535 } else if (sigismember(&new, signal)) {
536 sa.sa_sigaction = maybe_now_maybe_later;
538 sa.sa_sigaction = interrupt_handle_now;
541 sigemptyset(&sa.sa_mask);
542 sigaddset_blockable(&sa.sa_mask);
543 sa.sa_flags = SA_SIGINFO | SA_RESTART;
545 sigaction(signal, &sa, NULL);
548 oldhandler = interrupt_handlers[signal];
549 interrupt_handlers[signal].c = handler;
551 sigprocmask(SIG_SETMASK, &old, 0);
553 FSHOW((stderr, "leaving POSIX install_handler(%d, ..)\n", signal));
555 return (unsigned long)oldhandler.lisp;
563 for (i = 0; i < NSIG; i++) {
564 interrupt_handlers[i].c =
565 /* (The cast here blasts away the distinction between
566 * SA_SIGACTION-style three-argument handlers and
567 * signal(..)-style one-argument handlers, which is OK
568 * because it works to call the 1-argument form where the
569 * 3-argument form is expected.) */
570 (void (*)(int, siginfo_t*, void*))SIG_DFL;