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>
55 #include "interrupt.h"
64 #include "genesis/fdefn.h"
65 #include "genesis/simple-fun.h"
69 void run_deferred_handler(struct interrupt_data *data, void *v_context) ;
70 static void store_signal_data_for_later (struct interrupt_data *data,
71 void *handler, int signal,
73 os_context_t *context);
74 boolean interrupt_maybe_gc_int(int signal, siginfo_t *info, void *v_context);
76 extern volatile lispobj all_threads_lock;
79 * This is a workaround for some slightly silly Linux/GNU Libc
80 * behaviour: glibc defines sigset_t to support 1024 signals, which is
81 * more than the kernel. This is usually not a problem, but becomes
82 * one when we want to save a signal mask from a ucontext, and restore
83 * it later into another ucontext: the ucontext is allocated on the
84 * stack by the kernel, so copying a libc-sized sigset_t into it will
85 * overflow and cause other data on the stack to be corrupted */
87 #define REAL_SIGSET_SIZE_BYTES ((NSIG/8))
89 void sigaddset_blockable(sigset_t *s)
93 sigaddset(s, SIGQUIT);
94 sigaddset(s, SIGPIPE);
95 sigaddset(s, SIGALRM);
98 sigaddset(s, SIGTSTP);
99 sigaddset(s, SIGCHLD);
101 sigaddset(s, SIGXCPU);
102 sigaddset(s, SIGXFSZ);
103 sigaddset(s, SIGVTALRM);
104 sigaddset(s, SIGPROF);
105 sigaddset(s, SIGWINCH);
106 sigaddset(s, SIGUSR1);
107 sigaddset(s, SIGUSR2);
108 #ifdef LISP_FEATURE_SB_THREAD
109 sigaddset(s, SIG_STOP_FOR_GC);
110 sigaddset(s, SIG_INTERRUPT_THREAD);
114 /* When we catch an internal error, should we pass it back to Lisp to
115 * be handled in a high-level way? (Early in cold init, the answer is
116 * 'no', because Lisp is still too brain-dead to handle anything.
117 * After sufficient initialization has been completed, the answer
119 boolean internal_errors_enabled = 0;
121 struct interrupt_data * global_interrupt_data;
123 /* At the toplevel repl we routinely call this function. The signal
124 * mask ought to be clear anyway most of the time, but may be non-zero
125 * if we were interrupted e.g. while waiting for a queue. */
127 void reset_signal_mask ()
131 sigprocmask(SIG_SETMASK,&new,0);
138 * utility routines used by various signal handlers
142 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
144 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
148 /* Build a fake stack frame or frames */
150 current_control_frame_pointer =
151 (lispobj *)(*os_context_register_addr(context, reg_CSP));
152 if ((lispobj *)(*os_context_register_addr(context, reg_CFP))
153 == current_control_frame_pointer) {
154 /* There is a small window during call where the callee's
155 * frame isn't built yet. */
156 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
157 == FUN_POINTER_LOWTAG) {
158 /* We have called, but not built the new frame, so
159 * build it for them. */
160 current_control_frame_pointer[0] =
161 *os_context_register_addr(context, reg_OCFP);
162 current_control_frame_pointer[1] =
163 *os_context_register_addr(context, reg_LRA);
164 current_control_frame_pointer += 8;
165 /* Build our frame on top of it. */
166 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
169 /* We haven't yet called, build our frame as if the
170 * partial frame wasn't there. */
171 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
174 /* We can't tell whether we are still in the caller if it had to
175 * allocate a stack frame due to stack arguments. */
176 /* This observation provoked some past CMUCL maintainer to ask
177 * "Can anything strange happen during return?" */
180 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
183 current_control_stack_pointer = current_control_frame_pointer + 8;
185 current_control_frame_pointer[0] = oldcont;
186 current_control_frame_pointer[1] = NIL;
187 current_control_frame_pointer[2] =
188 (lispobj)(*os_context_register_addr(context, reg_CODE));
193 fake_foreign_function_call(os_context_t *context)
196 struct thread *thread=arch_os_get_current_thread();
198 /* Get current Lisp state from context. */
200 dynamic_space_free_pointer =
201 (lispobj *)(*os_context_register_addr(context, reg_ALLOC));
202 #if defined(LISP_FEATURE_ALPHA)
203 if ((long)dynamic_space_free_pointer & 1) {
204 lose("dead in fake_foreign_function_call, context = %x", context);
209 current_binding_stack_pointer =
210 (lispobj *)(*os_context_register_addr(context, reg_BSP));
213 build_fake_control_stack_frames(thread,context);
215 /* Do dynamic binding of the active interrupt context index
216 * and save the context in the context array. */
218 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
220 if (context_index >= MAX_INTERRUPTS) {
221 lose("maximum interrupt nesting depth (%d) exceeded", MAX_INTERRUPTS);
224 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
225 make_fixnum(context_index + 1),thread);
227 thread->interrupt_contexts[context_index] = context;
229 /* no longer in Lisp now */
230 foreign_function_call_active = 1;
233 /* blocks all blockable signals. If you are calling from a signal handler,
234 * the usual signal mask will be restored from the context when the handler
235 * finishes. Otherwise, be careful */
238 undo_fake_foreign_function_call(os_context_t *context)
240 struct thread *thread=arch_os_get_current_thread();
241 /* Block all blockable signals. */
244 sigaddset_blockable(&block);
245 sigprocmask(SIG_BLOCK, &block, 0);
247 /* going back into Lisp */
248 foreign_function_call_active = 0;
250 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
254 /* Put the dynamic space free pointer back into the context. */
255 *os_context_register_addr(context, reg_ALLOC) =
256 (unsigned long) dynamic_space_free_pointer;
260 /* a handler for the signal caused by execution of a trap opcode
261 * signalling an internal error */
263 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
266 lispobj context_sap = 0;
268 fake_foreign_function_call(context);
270 /* Allocate the SAP object while the interrupts are still
272 if (internal_errors_enabled) {
273 context_sap = alloc_sap(context);
276 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
278 if (internal_errors_enabled) {
279 SHOW("in interrupt_internal_error");
281 /* Display some rudimentary debugging information about the
282 * error, so that even if the Lisp error handler gets badly
283 * confused, we have a chance to determine what's going on. */
284 describe_internal_error(context);
286 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
287 continuable ? T : NIL);
289 describe_internal_error(context);
290 /* There's no good way to recover from an internal error
291 * before the Lisp error handling mechanism is set up. */
292 lose("internal error too early in init, can't recover");
294 undo_fake_foreign_function_call(context); /* blocks signals again */
296 arch_skip_instruction(context);
301 interrupt_handle_pending(os_context_t *context)
303 struct thread *thread;
304 struct interrupt_data *data;
306 thread=arch_os_get_current_thread();
307 data=thread->interrupt_data;
309 /* FIXME: This is almost certainly wrong if we're here as the
310 * result of a pseudo-atomic as opposed to WITHOUT-INTERRUPTS. */
311 SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
313 /* restore the saved signal mask from the original signal (the
314 * one that interrupted us during the critical section) into the
315 * os_context for the signal we're currently in the handler for.
316 * This should ensure that when we return from the handler the
317 * blocked signals are unblocked */
319 memcpy(os_context_sigmask_addr(context), &data->pending_mask,
320 REAL_SIGSET_SIZE_BYTES);
322 sigemptyset(&data->pending_mask);
323 /* This will break on sparc linux: the deferred handler really wants
324 * to be called with a void_context */
325 run_deferred_handler(data,(void *)context);
329 * the two main signal handlers:
330 * interrupt_handle_now(..)
331 * maybe_now_maybe_later(..)
333 * to which we have added interrupt_handle_now_handler(..). Why?
334 * Well, mostly because the SPARC/Linux platform doesn't quite do
335 * signals the way we want them done. The third argument in the
336 * handler isn't filled in by the kernel properly, so we fix it up
337 * ourselves in the arch_os_get_context(..) function; however, we only
338 * want to do this when we first hit the handler, and not when
339 * interrupt_handle_now(..) is being called from some other handler
340 * (when the fixup will already have been done). -- CSR, 2002-07-23
344 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
346 os_context_t *context = (os_context_t*)void_context;
347 struct thread *thread=arch_os_get_current_thread();
348 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
349 boolean were_in_lisp;
351 union interrupt_handler handler;
353 #ifdef LISP_FEATURE_LINUX
354 /* Under Linux on some architectures, we appear to have to restore
355 the FPU control word from the context, as after the signal is
356 delivered we appear to have a null FPU control word. */
357 os_restore_fp_control(context);
359 handler = thread->interrupt_data->interrupt_handlers[signal];
361 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
365 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
366 were_in_lisp = !foreign_function_call_active;
370 fake_foreign_function_call(context);
375 "/entering interrupt_handle_now(%d, info, context)\n",
379 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
381 /* This can happen if someone tries to ignore or default one
382 * of the signals we need for runtime support, and the runtime
383 * support decides to pass on it. */
384 lose("no handler for signal %d in interrupt_handle_now(..)", signal);
386 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
387 /* Once we've decided what to do about contexts in a
388 * return-elsewhere world (the original context will no longer
389 * be available; should we copy it or was nobody using it anyway?)
390 * then we should convert this to return-elsewhere */
392 /* CMUCL comment said "Allocate the SAPs while the interrupts
393 * are still disabled.". I (dan, 2003.08.21) assume this is
394 * because we're not in pseudoatomic and allocation shouldn't
395 * be interrupted. In which case it's no longer an issue as
396 * all our allocation from C now goes through a PA wrapper,
397 * but still, doesn't hurt */
399 lispobj info_sap,context_sap = alloc_sap(context);
400 info_sap = alloc_sap(info);
401 /* Allow signals again. */
402 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
405 SHOW("calling Lisp-level handler");
408 funcall3(handler.lisp,
415 SHOW("calling C-level handler");
418 /* Allow signals again. */
419 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
421 (*handler.c)(signal, info, void_context);
424 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
428 undo_fake_foreign_function_call(context); /* block signals again */
433 "/returning from interrupt_handle_now(%d, info, context)\n",
438 /* This is called at the end of a critical section if the indications
439 * are that some signal was deferred during the section. Note that as
440 * far as C or the kernel is concerned we dealt with the signal
441 * already; we're just doing the Lisp-level processing now that we
445 run_deferred_handler(struct interrupt_data *data, void *v_context) {
446 (*(data->pending_handler))
447 (data->pending_signal,&(data->pending_info), v_context);
448 data->pending_handler=0;
452 maybe_defer_handler(void *handler, struct interrupt_data *data,
453 int signal, siginfo_t *info, os_context_t *context)
455 struct thread *thread=arch_os_get_current_thread();
456 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
457 store_signal_data_for_later(data,handler,signal,info,context);
458 SetSymbolValue(INTERRUPT_PENDING, T,thread);
461 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
462 * actually use its argument for anything on x86, so this branch
463 * may succeed even when context is null (gencgc alloc()) */
465 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
466 (!foreign_function_call_active) &&
468 arch_pseudo_atomic_atomic(context)) {
469 store_signal_data_for_later(data,handler,signal,info,context);
470 arch_set_pseudo_atomic_interrupted(context);
476 store_signal_data_for_later (struct interrupt_data *data, void *handler,
478 siginfo_t *info, os_context_t *context)
480 data->pending_handler = handler;
481 data->pending_signal = signal;
483 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
485 /* the signal mask in the context (from before we were
486 * interrupted) is copied to be restored when
487 * run_deferred_handler happens. Then the usually-blocked
488 * signals are added to the mask in the context so that we are
489 * running with blocked signals when the handler returns */
490 sigemptyset(&(data->pending_mask));
491 memcpy(&(data->pending_mask),
492 os_context_sigmask_addr(context),
493 REAL_SIGSET_SIZE_BYTES);
494 sigaddset_blockable(os_context_sigmask_addr(context));
496 /* this is also called from gencgc alloc(), in which case
497 * there has been no signal and is therefore no context. */
500 sigaddset_blockable(&new);
501 sigprocmask(SIG_BLOCK,&new,&(data->pending_mask));
507 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
509 os_context_t *context = arch_os_get_context(&void_context);
510 struct thread *thread=arch_os_get_current_thread();
511 struct interrupt_data *data=thread->interrupt_data;
512 #ifdef LISP_FEATURE_LINUX
513 os_restore_fp_control(context);
515 if(maybe_defer_handler(interrupt_handle_now,data,
516 signal,info,context))
518 interrupt_handle_now(signal, info, context);
519 #ifdef LISP_FEATURE_DARWIN
520 /* Work around G5 bug */
521 DARWIN_FIX_CONTEXT(context);
525 #ifdef LISP_FEATURE_SB_THREAD
527 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
529 os_context_t *context = arch_os_get_context(&void_context);
530 struct thread *thread=arch_os_get_current_thread();
531 struct interrupt_data *data=thread->interrupt_data;
535 if(maybe_defer_handler(sig_stop_for_gc_handler,data,
536 signal,info,context)) {
539 /* need the context stored so it can have registers scavenged */
540 fake_foreign_function_call(context);
543 for(i=1;i<NSIG;i++) sigaddset(&ss,i); /* Block everything. */
544 sigprocmask(SIG_BLOCK,&ss,0);
546 /* The GC can't tell if a thread is a zombie, so this would be a
547 * good time to let the kernel reap any of our children in that
548 * awful state, to stop them from being waited for indefinitely.
549 * Userland reaping is done later when GC is finished */
551 if(thread->state!=STATE_STOPPING) {
552 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
553 fixnum_value(thread->state));
555 thread->state=STATE_STOPPED;
557 sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
559 if(thread->state!=STATE_STOPPED) {
560 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
561 fixnum_value(thread->state));
563 thread->state=STATE_RUNNING;
565 undo_fake_foreign_function_call(context);
570 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
572 os_context_t *context = arch_os_get_context(&void_context);
573 interrupt_handle_now(signal, info, context);
574 #ifdef LISP_FEATURE_DARWIN
575 DARWIN_FIX_CONTEXT(context);
580 * stuff to detect and handle hitting the GC trigger
583 #ifndef LISP_FEATURE_GENCGC
584 /* since GENCGC has its own way to record trigger */
586 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
588 if (current_auto_gc_trigger == NULL)
591 void *badaddr=arch_get_bad_addr(signal,info,context);
592 return (badaddr >= (void *)current_auto_gc_trigger &&
593 badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE));
598 /* manipulate the signal context and stack such that when the handler
599 * returns, it will call function instead of whatever it was doing
603 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
604 extern void post_signal_tramp(void);
605 void arrange_return_to_lisp_function(os_context_t *context, lispobj function)
607 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
608 void * fun=native_pointer(function);
609 void *code = &(((struct simple_fun *) fun)->code);
612 /* Build a stack frame showing `interrupted' so that the
613 * user's backtrace makes (as much) sense (as usual) */
614 #ifdef LISP_FEATURE_X86
615 /* Suppose the existence of some function that saved all
616 * registers, called call_into_lisp, then restored GP registers and
617 * returned. It would look something like this:
624 pushl {address of function to call}
625 call 0x8058db0 <call_into_lisp>
631 * What we do here is set up the stack that call_into_lisp would
632 * expect to see if it had been called by this code, and frob the
633 * signal context so that signal return goes directly to call_into_lisp,
634 * and when that function (and the lisp function it invoked) returns,
635 * it returns to the second half of this imaginary function which
636 * restores all registers and returns to C
638 * For this to work, the latter part of the imaginary function
639 * must obviously exist in reality. That would be post_signal_tramp
642 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
644 *(sp-14) = post_signal_tramp; /* return address for call_into_lisp */
645 *(sp-13) = function; /* args for call_into_lisp : function*/
646 *(sp-12) = 0; /* arg array */
647 *(sp-11) = 0; /* no. args */
648 /* this order matches that used in POPAD */
649 *(sp-10)=*os_context_register_addr(context,reg_EDI);
650 *(sp-9)=*os_context_register_addr(context,reg_ESI);
652 *(sp-8)=*os_context_register_addr(context,reg_ESP)-8;
654 *(sp-6)=*os_context_register_addr(context,reg_EBX);
656 *(sp-5)=*os_context_register_addr(context,reg_EDX);
657 *(sp-4)=*os_context_register_addr(context,reg_ECX);
658 *(sp-3)=*os_context_register_addr(context,reg_EAX);
659 *(sp-2)=*os_context_register_addr(context,reg_EBP);
660 *(sp-1)=*os_context_pc_addr(context);
662 #elif defined(LISP_FEATURE_X86_64)
663 u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP);
664 *(sp-19) = post_signal_tramp; /* return address for call_into_lisp */
666 *(sp-18)=*os_context_register_addr(context,reg_R15);
667 *(sp-17)=*os_context_register_addr(context,reg_R14);
668 *(sp-16)=*os_context_register_addr(context,reg_R13);
669 *(sp-15)=*os_context_register_addr(context,reg_R12);
670 *(sp-14)=*os_context_register_addr(context,reg_R11);
671 *(sp-13)=*os_context_register_addr(context,reg_R10);
672 *(sp-12)=*os_context_register_addr(context,reg_R9);
673 *(sp-11)=*os_context_register_addr(context,reg_R8);
674 *(sp-10)=*os_context_register_addr(context,reg_RDI);
675 *(sp-9)=*os_context_register_addr(context,reg_RSI);
676 *(sp-8)=*os_context_register_addr(context,reg_RSP)-16;
678 *(sp-6)=*os_context_register_addr(context,reg_RBX);
679 *(sp-5)=*os_context_register_addr(context,reg_RDX);
680 *(sp-4)=*os_context_register_addr(context,reg_RCX);
681 *(sp-3)=*os_context_register_addr(context,reg_RAX);
682 *(sp-2)=*os_context_register_addr(context,reg_RBP);
683 *(sp-1)=*os_context_pc_addr(context);
685 *os_context_register_addr(context,reg_RDI) = function; /* function */
686 *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */
687 *os_context_register_addr(context,reg_RDX) = 0; /* no. args */
689 struct thread *th=arch_os_get_current_thread();
690 build_fake_control_stack_frames(th,context);
693 #ifdef LISP_FEATURE_X86
694 *os_context_pc_addr(context) = call_into_lisp;
695 *os_context_register_addr(context,reg_ECX) = 0;
696 *os_context_register_addr(context,reg_EBP) = sp-2;
698 *os_context_register_addr(context,reg_UESP) = sp-14;
700 *os_context_register_addr(context,reg_ESP) = sp-14;
702 #elif defined(LISP_FEATURE_X86_64)
703 *os_context_pc_addr(context) = call_into_lisp;
704 *os_context_register_addr(context,reg_RCX) = 0;
705 *os_context_register_addr(context,reg_RBP) = sp-2;
706 *os_context_register_addr(context,reg_RSP) = sp-19;
708 /* this much of the calling convention is common to all
710 *os_context_pc_addr(context) = code;
711 *os_context_register_addr(context,reg_NARGS) = 0;
712 *os_context_register_addr(context,reg_LIP) = code;
713 *os_context_register_addr(context,reg_CFP) =
714 current_control_frame_pointer;
716 #ifdef ARCH_HAS_NPC_REGISTER
717 *os_context_npc_addr(context) =
718 4 + *os_context_pc_addr(context);
720 #ifdef LISP_FEATURE_SPARC
721 *os_context_register_addr(context,reg_CODE) =
722 fun + FUN_POINTER_LOWTAG;
726 #ifdef LISP_FEATURE_SB_THREAD
727 void interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
729 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
730 struct thread *th=arch_os_get_current_thread();
731 struct interrupt_data *data=
732 th ? th->interrupt_data : global_interrupt_data;
733 if(maybe_defer_handler(interrupt_thread_handler,data,num,info,context)){
736 arrange_return_to_lisp_function(context,info->si_value.sival_int);
739 void thread_exit_handler(int num, siginfo_t *info, void *v_context)
740 { /* called when a child thread exits */
746 /* KLUDGE: Theoretically the approach we use for undefined alien
747 * variables should work for functions as well, but on PPC/Darwin
748 * we get bus error at bogus addresses instead, hence this workaround,
749 * that has the added benefit of automatically discriminating between
750 * functions and variables.
752 void undefined_alien_function() {
753 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR));
756 boolean handle_guard_page_triggered(os_context_t *context,void *addr){
757 struct thread *th=arch_os_get_current_thread();
759 /* note the os_context hackery here. When the signal handler returns,
760 * it won't go back to what it was doing ... */
761 if(addr >= CONTROL_STACK_GUARD_PAGE(th) &&
762 addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) {
763 /* We hit the end of the control stack: disable guard page
764 * protection so the error handler has some headroom, protect the
765 * previous page so that we can catch returns from the guard page
767 protect_control_stack_guard_page(th->pid,0);
768 protect_control_stack_return_guard_page(th->pid,1);
770 arrange_return_to_lisp_function
771 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
774 else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) &&
775 addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) {
776 /* We're returning from the guard page: reprotect it, and
777 * unprotect this one. This works even if we somehow missed
778 * the return-guard-page, and hit it on our way to new
779 * exhaustion instead. */
780 protect_control_stack_guard_page(th->pid,1);
781 protect_control_stack_return_guard_page(th->pid,0);
784 else if (addr >= undefined_alien_address &&
785 addr < undefined_alien_address + os_vm_page_size) {
786 arrange_return_to_lisp_function
787 (context, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR));
793 #ifndef LISP_FEATURE_GENCGC
794 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
795 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
796 * whether the signal was due to treading on the mprotect()ed zone -
797 * and if so, arrange for a GC to happen. */
798 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
801 interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
803 os_context_t *context=(os_context_t *) void_context;
804 struct thread *th=arch_os_get_current_thread();
805 struct interrupt_data *data=
806 th ? th->interrupt_data : global_interrupt_data;
808 if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
809 clear_auto_gc_trigger();
810 if(!maybe_defer_handler
811 (interrupt_maybe_gc_int,data,signal,info,void_context))
812 interrupt_maybe_gc_int(signal,info,void_context);
821 kludge_sigset_for_gc(sigset_t * set)
823 #ifndef LISP_FEATURE_GENCGC
824 /* FIXME: It is not sure if GENCGC is really right here: maybe this
825 * really affects eg. only Sparc and PPC. And the following KLUDGE
826 * could really use real fixing as well.
828 * KLUDGE: block some async signals that seem to have the ability
829 * to hang us in an uninterruptible state during GC -- at least
830 * part of the time. The main beneficiary of this is SB-SPROF, as
831 * SIGPROF was almost certain to be eventually triggered at a bad
832 * moment, rendering it virtually useless. SIGINT and SIGIO from
833 * user or eg. Slime also seemed to occasionally do this.
835 * The problem this papers over appears to be something going awry
836 * in SB-UNIX:RECEIVE-PENDING-SIGNALS at the end of the
837 * WITHOUT-INTERRUPTS in SUB-GC: adding debugging output shows us
838 * leaving the body of W-I, but never entering sigtrap_handler.
840 * Empirically, it seems that the problem is only triggered if the
841 * GC was triggered/deferred during a PA section, but this is not
842 * a sufficient condition: some collections triggered in such a
843 * manner seem to be able to receive and defer a signal during the
844 * GC without issues. Likewise empirically, it seems that the
845 * problem arises more often with floating point code then not. Eg
846 * (LOOP (* (RANDOM 1.0) (RANDOM 1.0))) will eventually hang if
847 * run with SB-SPROF on, but (LOOP (FOO (MAKE-LIST 24))) will not.
848 * All this makes some badnesss in the interaction between PA and
849 * W-I seem likely, possibly in the form of one or more bad VOPs.
851 * For additional entertainment on the affected platforms we
852 * currently use an actual illegal instruction to receive pending
853 * interrupts instead of a trap: whether this has any bearing on
854 * the matter is unknown.
856 * Apparently CMUCL blocks everything but SIGILL for GC on Sparc,
857 * possibly for this very reason.
861 sigdelset(set, SIGPROF);
862 sigdelset(set, SIGIO);
863 sigdelset(set, SIGINT);
867 /* this is also used by gencgc, in alloc() */
869 interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
872 os_context_t *context=(os_context_t *) void_context;
873 fake_foreign_function_call(context);
875 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
876 * which case we will be running with no gc trigger barrier
877 * thing for a while. But it shouldn't be long until the end
880 * FIXME: It would be good to protect the end of dynamic space
881 * and signal a storage condition from there.
884 /* enable some signals before calling into Lisp */
886 sigaddset_blockable(&new);
887 kludge_sigset_for_gc(&new);
888 sigprocmask(SIG_UNBLOCK,&new,0);
890 funcall0(SymbolFunction(SUB_GC));
892 undo_fake_foreign_function_call(context);
898 * noise to install handlers
902 undoably_install_low_level_interrupt_handler (int signal,
908 struct thread *th=arch_os_get_current_thread();
909 struct interrupt_data *data=
910 th ? th->interrupt_data : global_interrupt_data;
912 if (0 > signal || signal >= NSIG) {
913 lose("bad signal number %d", signal);
916 sa.sa_sigaction = handler;
917 sigemptyset(&sa.sa_mask);
918 sigaddset_blockable(&sa.sa_mask);
919 sa.sa_flags = SA_SIGINFO | SA_RESTART;
920 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
921 if((signal==SIG_MEMORY_FAULT)
922 #ifdef SIG_INTERRUPT_THREAD
923 || (signal==SIG_INTERRUPT_THREAD)
926 sa.sa_flags|= SA_ONSTACK;
929 sigaction(signal, &sa, NULL);
930 data->interrupt_low_level_handlers[signal] =
931 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
934 /* This is called from Lisp. */
936 install_handler(int signal, void handler(int, siginfo_t*, void*))
940 union interrupt_handler oldhandler;
941 struct thread *th=arch_os_get_current_thread();
942 struct interrupt_data *data=
943 th ? th->interrupt_data : global_interrupt_data;
945 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
948 sigaddset(&new, signal);
949 sigprocmask(SIG_BLOCK, &new, &old);
952 sigaddset_blockable(&new);
954 FSHOW((stderr, "/data->interrupt_low_level_handlers[signal]=%d\n",
955 data->interrupt_low_level_handlers[signal]));
956 if (data->interrupt_low_level_handlers[signal]==0) {
957 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
958 ARE_SAME_HANDLER(handler, SIG_IGN)) {
959 sa.sa_sigaction = handler;
960 } else if (sigismember(&new, signal)) {
961 sa.sa_sigaction = maybe_now_maybe_later;
963 sa.sa_sigaction = interrupt_handle_now_handler;
966 sigemptyset(&sa.sa_mask);
967 sigaddset_blockable(&sa.sa_mask);
968 sa.sa_flags = SA_SIGINFO | SA_RESTART;
969 sigaction(signal, &sa, NULL);
972 oldhandler = data->interrupt_handlers[signal];
973 data->interrupt_handlers[signal].c = handler;
975 sigprocmask(SIG_SETMASK, &old, 0);
977 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
979 return (unsigned long)oldhandler.lisp;
986 SHOW("entering interrupt_init()");
987 global_interrupt_data=calloc(sizeof(struct interrupt_data), 1);
989 /* Set up high level handler information. */
990 for (i = 0; i < NSIG; i++) {
991 global_interrupt_data->interrupt_handlers[i].c =
992 /* (The cast here blasts away the distinction between
993 * SA_SIGACTION-style three-argument handlers and
994 * signal(..)-style one-argument handlers, which is OK
995 * because it works to call the 1-argument form where the
996 * 3-argument form is expected.) */
997 (void (*)(int, siginfo_t*, void*))SIG_DFL;
1000 SHOW("returning from interrupt_init()");