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();
634 #ifdef LISP_FEATURE_LINUX
635 os_restore_fp_control(context
);
637 check_blockables_blocked_or_lose();
638 check_interrupts_enabled_or_lose(context
);
639 (*thread
->interrupt_data
->interrupt_low_level_handlers
[signal
])
640 (signal
, info
, void_context
);
641 #ifdef LISP_FEATURE_DARWIN
642 /* Work around G5 bug */
643 DARWIN_FIX_CONTEXT(context
);
648 low_level_maybe_now_maybe_later(int signal
, siginfo_t
*info
, void *void_context
)
650 os_context_t
*context
= arch_os_get_context(&void_context
);
651 struct thread
*thread
=arch_os_get_current_thread();
652 struct interrupt_data
*data
=thread
->interrupt_data
;
653 #ifdef LISP_FEATURE_LINUX
654 os_restore_fp_control(context
);
656 if(maybe_defer_handler(low_level_interrupt_handle_now
,data
,
657 signal
,info
,context
))
659 low_level_interrupt_handle_now(signal
, info
, context
);
660 #ifdef LISP_FEATURE_DARWIN
661 /* Work around G5 bug */
662 DARWIN_FIX_CONTEXT(context
);
666 #ifdef LISP_FEATURE_SB_THREAD
669 sig_stop_for_gc_handler(int signal
, siginfo_t
*info
, void *void_context
)
671 os_context_t
*context
= arch_os_get_context(&void_context
);
672 struct thread
*thread
=arch_os_get_current_thread();
676 if ((arch_pseudo_atomic_atomic(context
) ||
677 SymbolValue(GC_INHIBIT
,thread
) != NIL
)) {
678 SetSymbolValue(STOP_FOR_GC_PENDING
,T
,thread
);
679 if (SymbolValue(GC_INHIBIT
,thread
) == NIL
)
680 arch_set_pseudo_atomic_interrupted(context
);
681 FSHOW_SIGNAL((stderr
,"thread=%lu sig_stop_for_gc deferred\n",
684 /* need the context stored so it can have registers scavenged */
685 fake_foreign_function_call(context
);
688 for(i
=1;i
<NSIG
;i
++) sigaddset(&ss
,i
); /* Block everything. */
689 thread_sigmask(SIG_BLOCK
,&ss
,0);
691 /* The GC can't tell if a thread is a zombie, so this would be a
692 * good time to let the kernel reap any of our children in that
693 * awful state, to stop them from being waited for indefinitely.
694 * Userland reaping is done later when GC is finished */
695 if(thread
->state
!=STATE_RUNNING
) {
696 lose("sig_stop_for_gc_handler: wrong thread state: %ld\n",
697 fixnum_value(thread
->state
));
699 thread
->state
=STATE_SUSPENDED
;
700 FSHOW_SIGNAL((stderr
,"thread=%lu suspended\n",thread
->os_thread
));
702 sigemptyset(&ss
); sigaddset(&ss
,SIG_STOP_FOR_GC
);
704 FSHOW_SIGNAL((stderr
,"thread=%lu resumed\n",thread
->os_thread
));
705 if(thread
->state
!=STATE_RUNNING
) {
706 lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n",
707 fixnum_value(thread
->state
));
710 undo_fake_foreign_function_call(context
);
716 interrupt_handle_now_handler(int signal
, siginfo_t
*info
, void *void_context
)
718 os_context_t
*context
= arch_os_get_context(&void_context
);
719 interrupt_handle_now(signal
, info
, context
);
720 #ifdef LISP_FEATURE_DARWIN
721 DARWIN_FIX_CONTEXT(context
);
726 * stuff to detect and handle hitting the GC trigger
729 #ifndef LISP_FEATURE_GENCGC
730 /* since GENCGC has its own way to record trigger */
732 gc_trigger_hit(int signal
, siginfo_t
*info
, os_context_t
*context
)
734 if (current_auto_gc_trigger
== NULL
)
737 void *badaddr
=arch_get_bad_addr(signal
,info
,context
);
738 return (badaddr
>= (void *)current_auto_gc_trigger
&&
739 badaddr
<((void *)current_dynamic_space
+ DYNAMIC_SPACE_SIZE
));
744 /* manipulate the signal context and stack such that when the handler
745 * returns, it will call function instead of whatever it was doing
749 #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
750 int *context_eflags_addr(os_context_t
*context
);
753 extern lispobj
call_into_lisp(lispobj fun
, lispobj
*args
, int nargs
);
754 extern void post_signal_tramp(void);
755 void arrange_return_to_lisp_function(os_context_t
*context
, lispobj function
)
757 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
758 void * fun
=native_pointer(function
);
759 void *code
= &(((struct simple_fun
*) fun
)->code
);
762 /* Build a stack frame showing `interrupted' so that the
763 * user's backtrace makes (as much) sense (as usual) */
765 /* FIXME: what about restoring fp state? */
766 /* FIXME: what about restoring errno? */
767 #ifdef LISP_FEATURE_X86
768 /* Suppose the existence of some function that saved all
769 * registers, called call_into_lisp, then restored GP registers and
770 * returned. It would look something like this:
778 pushl {address of function to call}
779 call 0x8058db0 <call_into_lisp>
786 * What we do here is set up the stack that call_into_lisp would
787 * expect to see if it had been called by this code, and frob the
788 * signal context so that signal return goes directly to call_into_lisp,
789 * and when that function (and the lisp function it invoked) returns,
790 * it returns to the second half of this imaginary function which
791 * restores all registers and returns to C
793 * For this to work, the latter part of the imaginary function
794 * must obviously exist in reality. That would be post_signal_tramp
797 u32
*sp
=(u32
*)*os_context_register_addr(context
,reg_ESP
);
799 /* return address for call_into_lisp: */
800 *(sp
-15) = (u32
)post_signal_tramp
;
801 *(sp
-14) = function
; /* args for call_into_lisp : function*/
802 *(sp
-13) = 0; /* arg array */
803 *(sp
-12) = 0; /* no. args */
804 /* this order matches that used in POPAD */
805 *(sp
-11)=*os_context_register_addr(context
,reg_EDI
);
806 *(sp
-10)=*os_context_register_addr(context
,reg_ESI
);
808 *(sp
-9)=*os_context_register_addr(context
,reg_ESP
)-8;
809 /* POPAD ignores the value of ESP: */
811 *(sp
-7)=*os_context_register_addr(context
,reg_EBX
);
813 *(sp
-6)=*os_context_register_addr(context
,reg_EDX
);
814 *(sp
-5)=*os_context_register_addr(context
,reg_ECX
);
815 *(sp
-4)=*os_context_register_addr(context
,reg_EAX
);
816 *(sp
-3)=*context_eflags_addr(context
);
817 *(sp
-2)=*os_context_register_addr(context
,reg_EBP
);
818 *(sp
-1)=*os_context_pc_addr(context
);
820 #elif defined(LISP_FEATURE_X86_64)
821 u64
*sp
=(u64
*)*os_context_register_addr(context
,reg_RSP
);
822 /* return address for call_into_lisp: */
823 *(sp
-18) = (u64
)post_signal_tramp
;
825 *(sp
-17)=*os_context_register_addr(context
,reg_R15
);
826 *(sp
-16)=*os_context_register_addr(context
,reg_R14
);
827 *(sp
-15)=*os_context_register_addr(context
,reg_R13
);
828 *(sp
-14)=*os_context_register_addr(context
,reg_R12
);
829 *(sp
-13)=*os_context_register_addr(context
,reg_R11
);
830 *(sp
-12)=*os_context_register_addr(context
,reg_R10
);
831 *(sp
-11)=*os_context_register_addr(context
,reg_R9
);
832 *(sp
-10)=*os_context_register_addr(context
,reg_R8
);
833 *(sp
-9)=*os_context_register_addr(context
,reg_RDI
);
834 *(sp
-8)=*os_context_register_addr(context
,reg_RSI
);
835 /* skip RBP and RSP */
836 *(sp
-7)=*os_context_register_addr(context
,reg_RBX
);
837 *(sp
-6)=*os_context_register_addr(context
,reg_RDX
);
838 *(sp
-5)=*os_context_register_addr(context
,reg_RCX
);
839 *(sp
-4)=*os_context_register_addr(context
,reg_RAX
);
840 *(sp
-3)=*context_eflags_addr(context
);
841 *(sp
-2)=*os_context_register_addr(context
,reg_RBP
);
842 *(sp
-1)=*os_context_pc_addr(context
);
844 *os_context_register_addr(context
,reg_RDI
) =
845 (os_context_register_t
)function
; /* function */
846 *os_context_register_addr(context
,reg_RSI
) = 0; /* arg. array */
847 *os_context_register_addr(context
,reg_RDX
) = 0; /* no. args */
849 struct thread
*th
=arch_os_get_current_thread();
850 build_fake_control_stack_frames(th
,context
);
853 #ifdef LISP_FEATURE_X86
854 *os_context_pc_addr(context
) = (os_context_register_t
)call_into_lisp
;
855 *os_context_register_addr(context
,reg_ECX
) = 0;
856 *os_context_register_addr(context
,reg_EBP
) = (os_context_register_t
)(sp
-2);
858 *os_context_register_addr(context
,reg_UESP
) =
859 (os_context_register_t
)(sp
-15);
861 *os_context_register_addr(context
,reg_ESP
) = (os_context_register_t
)(sp
-15);
863 #elif defined(LISP_FEATURE_X86_64)
864 *os_context_pc_addr(context
) = (os_context_register_t
)call_into_lisp
;
865 *os_context_register_addr(context
,reg_RCX
) = 0;
866 *os_context_register_addr(context
,reg_RBP
) = (os_context_register_t
)(sp
-2);
867 *os_context_register_addr(context
,reg_RSP
) = (os_context_register_t
)(sp
-18);
869 /* this much of the calling convention is common to all
871 *os_context_pc_addr(context
) = (os_context_register_t
)code
;
872 *os_context_register_addr(context
,reg_NARGS
) = 0;
873 *os_context_register_addr(context
,reg_LIP
) = (os_context_register_t
)code
;
874 *os_context_register_addr(context
,reg_CFP
) =
875 (os_context_register_t
)current_control_frame_pointer
;
877 #ifdef ARCH_HAS_NPC_REGISTER
878 *os_context_npc_addr(context
) =
879 4 + *os_context_pc_addr(context
);
881 #ifdef LISP_FEATURE_SPARC
882 *os_context_register_addr(context
,reg_CODE
) =
883 (os_context_register_t
)(fun
+ FUN_POINTER_LOWTAG
);
887 #ifdef LISP_FEATURE_SB_THREAD
888 void interrupt_thread_handler(int num
, siginfo_t
*info
, void *v_context
)
890 os_context_t
*context
= (os_context_t
*)arch_os_get_context(&v_context
);
891 /* The order of interrupt execution is peculiar. If thread A
892 * interrupts thread B with I1, I2 and B for some reason receives
893 * I1 when FUN2 is already on the list, then it is FUN2 that gets
894 * to run first. But when FUN2 is run SIG_INTERRUPT_THREAD is
895 * enabled again and I2 hits pretty soon in FUN2 and run
896 * FUN1. This is of course just one scenario, and the order of
897 * thread interrupt execution is undefined. */
898 struct thread
*th
=arch_os_get_current_thread();
900 if (th
->state
!= STATE_RUNNING
)
901 lose("interrupt_thread_handler: thread %ld in wrong state: %d\n",
902 th
->os_thread
,fixnum_value(th
->state
));
903 get_spinlock(&th
->interrupt_fun_lock
,(long)th
);
904 c
=((struct cons
*)native_pointer(th
->interrupt_fun
));
905 arrange_return_to_lisp_function(context
,c
->car
);
906 th
->interrupt_fun
=c
->cdr
;
907 release_spinlock(&th
->interrupt_fun_lock
);
912 /* KLUDGE: Theoretically the approach we use for undefined alien
913 * variables should work for functions as well, but on PPC/Darwin
914 * we get bus error at bogus addresses instead, hence this workaround,
915 * that has the added benefit of automatically discriminating between
916 * functions and variables.
918 void undefined_alien_function() {
919 funcall0(SymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR
));
922 boolean
handle_guard_page_triggered(os_context_t
*context
,os_vm_address_t addr
)
924 struct thread
*th
=arch_os_get_current_thread();
926 /* note the os_context hackery here. When the signal handler returns,
927 * it won't go back to what it was doing ... */
928 if(addr
>= CONTROL_STACK_GUARD_PAGE(th
) &&
929 addr
< CONTROL_STACK_GUARD_PAGE(th
) + os_vm_page_size
) {
930 /* We hit the end of the control stack: disable guard page
931 * protection so the error handler has some headroom, protect the
932 * previous page so that we can catch returns from the guard page
934 protect_control_stack_guard_page(th
,0);
935 protect_control_stack_return_guard_page(th
,1);
937 arrange_return_to_lisp_function
938 (context
, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR
));
941 else if(addr
>= CONTROL_STACK_RETURN_GUARD_PAGE(th
) &&
942 addr
< CONTROL_STACK_RETURN_GUARD_PAGE(th
) + os_vm_page_size
) {
943 /* We're returning from the guard page: reprotect it, and
944 * unprotect this one. This works even if we somehow missed
945 * the return-guard-page, and hit it on our way to new
946 * exhaustion instead. */
947 protect_control_stack_guard_page(th
,1);
948 protect_control_stack_return_guard_page(th
,0);
951 else if (addr
>= undefined_alien_address
&&
952 addr
< undefined_alien_address
+ os_vm_page_size
) {
953 arrange_return_to_lisp_function
954 (context
, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR
));
960 #ifndef LISP_FEATURE_GENCGC
961 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
962 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
963 * whether the signal was due to treading on the mprotect()ed zone -
964 * and if so, arrange for a GC to happen. */
965 extern unsigned long bytes_consed_between_gcs
; /* gc-common.c */
968 interrupt_maybe_gc(int signal
, siginfo_t
*info
, void *void_context
)
970 os_context_t
*context
=(os_context_t
*) void_context
;
971 struct thread
*th
=arch_os_get_current_thread();
972 struct interrupt_data
*data
=
973 th
? th
->interrupt_data
: global_interrupt_data
;
975 if(!foreign_function_call_active
&& gc_trigger_hit(signal
, info
, context
)){
976 struct thread
*thread
=arch_os_get_current_thread();
977 clear_auto_gc_trigger();
978 /* Don't flood the system with interrupts if the need to gc is
979 * already noted. This can happen for example when SUB-GC
980 * allocates or after a gc triggered in a WITHOUT-GCING. */
981 if (SymbolValue(GC_PENDING
,thread
) == NIL
) {
982 if (SymbolValue(GC_INHIBIT
,thread
) == NIL
) {
983 if (arch_pseudo_atomic_atomic(context
)) {
984 /* set things up so that GC happens when we finish
986 SetSymbolValue(GC_PENDING
,T
,thread
);
987 arch_set_pseudo_atomic_interrupted(context
);
989 interrupt_maybe_gc_int(signal
,info
,void_context
);
992 SetSymbolValue(GC_PENDING
,T
,thread
);
1002 /* this is also used by gencgc, in alloc() */
1004 interrupt_maybe_gc_int(int signal
, siginfo_t
*info
, void *void_context
)
1006 os_context_t
*context
=(os_context_t
*) void_context
;
1007 struct thread
*thread
=arch_os_get_current_thread();
1009 check_blockables_blocked_or_lose();
1010 fake_foreign_function_call(context
);
1012 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
1013 * which case we will be running with no gc trigger barrier
1014 * thing for a while. But it shouldn't be long until the end
1017 * FIXME: It would be good to protect the end of dynamic space
1018 * and signal a storage condition from there.
1021 /* Restore the signal mask from the interrupted context before
1022 * calling into Lisp if interrupts are enabled. Why not always?
1024 * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an
1025 * interrupt hits while in SUB-GC, it is deferred and the
1026 * os_context_sigmask of that interrupt is set to block further
1027 * deferrable interrupts (until the first one is
1028 * handled). Unfortunately, that context refers to this place and
1029 * when we return from here the signals will not be blocked.
1031 * A kludgy alternative is to propagate the sigmask change to the
1034 if(SymbolValue(INTERRUPTS_ENABLED
,thread
)!=NIL
)
1035 thread_sigmask(SIG_SETMASK
, os_context_sigmask_addr(context
), 0);
1036 #ifdef LISP_FEATURE_SB_THREAD
1039 sigaddset(&new,SIG_STOP_FOR_GC
);
1040 thread_sigmask(SIG_UNBLOCK
,&new,0);
1043 funcall0(SymbolFunction(SUB_GC
));
1045 undo_fake_foreign_function_call(context
);
1051 * noise to install handlers
1055 undoably_install_low_level_interrupt_handler (int signal
,
1060 struct sigaction sa
;
1061 struct thread
*th
=arch_os_get_current_thread();
1062 struct interrupt_data
*data
=
1063 th
? th
->interrupt_data
: global_interrupt_data
;
1065 if (0 > signal
|| signal
>= NSIG
) {
1066 lose("bad signal number %d", signal
);
1069 if (sigismember(&deferrable_sigset
,signal
))
1070 sa
.sa_sigaction
= low_level_maybe_now_maybe_later
;
1072 sa
.sa_sigaction
= handler
;
1074 sigemptyset(&sa
.sa_mask
);
1075 sigaddset_blockable(&sa
.sa_mask
);
1076 sa
.sa_flags
= SA_SIGINFO
| SA_RESTART
;
1077 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
1078 if((signal
==SIG_MEMORY_FAULT
)
1079 #ifdef SIG_INTERRUPT_THREAD
1080 || (signal
==SIG_INTERRUPT_THREAD
)
1083 sa
.sa_flags
|= SA_ONSTACK
;
1086 sigaction(signal
, &sa
, NULL
);
1087 data
->interrupt_low_level_handlers
[signal
] =
1088 (ARE_SAME_HANDLER(handler
, SIG_DFL
) ? 0 : handler
);
1091 /* This is called from Lisp. */
1093 install_handler(int signal
, void handler(int, siginfo_t
*, void*))
1095 struct sigaction sa
;
1097 union interrupt_handler oldhandler
;
1098 struct thread
*th
=arch_os_get_current_thread();
1099 struct interrupt_data
*data
=
1100 th
? th
->interrupt_data
: global_interrupt_data
;
1102 FSHOW((stderr
, "/entering POSIX install_handler(%d, ..)\n", signal
));
1105 sigaddset(&new, signal
);
1106 thread_sigmask(SIG_BLOCK
, &new, &old
);
1108 FSHOW((stderr
, "/data->interrupt_low_level_handlers[signal]=%x\n",
1109 (unsigned int)data
->interrupt_low_level_handlers
[signal
]));
1110 if (data
->interrupt_low_level_handlers
[signal
]==0) {
1111 if (ARE_SAME_HANDLER(handler
, SIG_DFL
) ||
1112 ARE_SAME_HANDLER(handler
, SIG_IGN
)) {
1113 sa
.sa_sigaction
= handler
;
1114 } else if (sigismember(&deferrable_sigset
, signal
)) {
1115 sa
.sa_sigaction
= maybe_now_maybe_later
;
1117 sa
.sa_sigaction
= interrupt_handle_now_handler
;
1120 sigemptyset(&sa
.sa_mask
);
1121 sigaddset_blockable(&sa
.sa_mask
);
1122 sa
.sa_flags
= SA_SIGINFO
| SA_RESTART
;
1123 sigaction(signal
, &sa
, NULL
);
1126 oldhandler
= data
->interrupt_handlers
[signal
];
1127 data
->interrupt_handlers
[signal
].c
= handler
;
1129 thread_sigmask(SIG_SETMASK
, &old
, 0);
1131 FSHOW((stderr
, "/leaving POSIX install_handler(%d, ..)\n", signal
));
1133 return (unsigned long)oldhandler
.lisp
;
1140 SHOW("entering interrupt_init()");
1141 sigemptyset(&deferrable_sigset
);
1142 sigemptyset(&blockable_sigset
);
1143 sigaddset_deferrable(&deferrable_sigset
);
1144 sigaddset_blockable(&blockable_sigset
);
1146 global_interrupt_data
=calloc(sizeof(struct interrupt_data
), 1);
1148 /* Set up high level handler information. */
1149 for (i
= 0; i
< NSIG
; i
++) {
1150 global_interrupt_data
->interrupt_handlers
[i
].c
=
1151 /* (The cast here blasts away the distinction between
1152 * SA_SIGACTION-style three-argument handlers and
1153 * signal(..)-style one-argument handlers, which is OK
1154 * because it works to call the 1-argument form where the
1155 * 3-argument form is expected.) */
1156 (void (*)(int, siginfo_t
*, void*))SIG_DFL
;
1159 SHOW("returning from interrupt_init()");