/* * interrupt-handling magic */ /* * This software is part of the SBCL system. See the README file for * more information. * * This software is derived from the CMU CL system, which was * written at Carnegie Mellon University and released into the * public domain. The software is in the public domain and is * provided with absolutely no warranty. See the COPYING and CREDITS * files for more information. */ /* As far as I can tell, what's going on here is: * * In the case of most signals, when Lisp asks us to handle the * signal, the outermost handler (the one actually passed to UNIX) is * either interrupt_handle_now(..) or maybe_now_maybe_later(..). * In that case, the Lisp-level handler is stored in interrupt_handlers[..] * and interrupt_low_level_handlers[..] is cleared. * * However, some signals need special handling, e.g. * * o the SIGSEGV (for e.g. Linux) or SIGBUS (for e.g. FreeBSD) used by the * garbage collector to detect violations of write protection, * because some cases of such signals (e.g. GC-related violations of * write protection) are handled at C level and never passed on to * Lisp. For such signals, we still store any Lisp-level handler * in interrupt_handlers[..], but for the outermost handle we use * the value from interrupt_low_level_handlers[..], instead of the * ordinary interrupt_handle_now(..) or interrupt_handle_later(..). * * o the SIGTRAP (Linux/Alpha) which Lisp code uses to handle breakpoints, * pseudo-atomic sections, and some classes of error (e.g. "function * not defined"). This never goes anywhere near the Lisp handlers at all. * See runtime/alpha-arch.c and code/signal.lisp * * - WHN 20000728, dan 20010128 */ #include "sbcl.h" #include #include #include #include #include #ifndef LISP_FEATURE_WIN32 #include #endif #include #include "runtime.h" #include "arch.h" #include "os.h" #include "interrupt.h" #include "globals.h" #include "lispregs.h" #include "validate.h" #include "gc.h" #include "alloc.h" #include "dynbind.h" #include "interr.h" #include "genesis/fdefn.h" #include "genesis/simple-fun.h" #include "genesis/cons.h" static void run_deferred_handler(struct interrupt_data *data, void *v_context); #ifndef LISP_FEATURE_WIN32 static void store_signal_data_for_later (struct interrupt_data *data, void *handler, int signal, siginfo_t *info, os_context_t *context); void sigaddset_deferrable(sigset_t *s) { sigaddset(s, SIGHUP); sigaddset(s, SIGINT); sigaddset(s, SIGQUIT); sigaddset(s, SIGPIPE); sigaddset(s, SIGALRM); sigaddset(s, SIGURG); sigaddset(s, SIGTSTP); sigaddset(s, SIGCHLD); sigaddset(s, SIGIO); sigaddset(s, SIGXCPU); sigaddset(s, SIGXFSZ); sigaddset(s, SIGVTALRM); sigaddset(s, SIGPROF); sigaddset(s, SIGWINCH); #if !((defined(LISP_FEATURE_DARWIN) || defined(LISP_FEATURE_FREEBSD)) && defined(LISP_FEATURE_SB_THREAD)) sigaddset(s, SIGUSR1); sigaddset(s, SIGUSR2); #endif #ifdef LISP_FEATURE_SB_THREAD sigaddset(s, SIG_INTERRUPT_THREAD); #endif } void sigaddset_blockable(sigset_t *s) { sigaddset_deferrable(s); #ifdef LISP_FEATURE_SB_THREAD #ifdef SIG_RESUME_FROM_GC sigaddset(s, SIG_RESUME_FROM_GC); #endif sigaddset(s, SIG_STOP_FOR_GC); #endif } /* initialized in interrupt_init */ static sigset_t deferrable_sigset; static sigset_t blockable_sigset; #endif void check_blockables_blocked_or_lose(void) { #if !defined(LISP_FEATURE_WIN32) /* Get the current sigmask, by blocking the empty set. */ sigset_t empty,current; int i; sigemptyset(&empty); thread_sigmask(SIG_BLOCK, &empty, ¤t); for(i = 1; i < NSIG; i++) { if (sigismember(&blockable_sigset, i) && !sigismember(¤t, i)) lose("blockable signal %d not blocked\n",i); } #endif } void unblock_gc_signals(void) { #ifdef LISP_FEATURE_SB_THREAD sigset_t new; sigemptyset(&new); #if defined(SIG_RESUME_FROM_GC) sigaddset(&new,SIG_RESUME_FROM_GC); #endif sigaddset(&new,SIG_STOP_FOR_GC); thread_sigmask(SIG_UNBLOCK,&new,0); #endif } inline static void check_interrupts_enabled_or_lose(os_context_t *context) { struct thread *thread=arch_os_get_current_thread(); if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) lose("interrupts not enabled\n"); if (arch_pseudo_atomic_atomic(context)) lose ("in pseudo atomic section\n"); } /* When we catch an internal error, should we pass it back to Lisp to * be handled in a high-level way? (Early in cold init, the answer is * 'no', because Lisp is still too brain-dead to handle anything. * After sufficient initialization has been completed, the answer * becomes 'yes'.) */ boolean internal_errors_enabled = 0; #ifndef LISP_FEATURE_WIN32 static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*); #endif union interrupt_handler interrupt_handlers[NSIG]; /* At the toplevel repl we routinely call this function. The signal * mask ought to be clear anyway most of the time, but may be non-zero * if we were interrupted e.g. while waiting for a queue. */ void reset_signal_mask(void) { #ifndef LISP_FEATURE_WIN32 sigset_t new; sigemptyset(&new); thread_sigmask(SIG_SETMASK,&new,0); #endif } void block_blockable_signals(void) { #ifndef LISP_FEATURE_WIN32 thread_sigmask(SIG_BLOCK, &blockable_sigset, 0); #endif } void block_deferrable_signals(void) { #ifndef LISP_FEATURE_WIN32 thread_sigmask(SIG_BLOCK, &deferrable_sigset, 0); #endif } /* * utility routines used by various signal handlers */ static void build_fake_control_stack_frames(struct thread *th,os_context_t *context) { #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK lispobj oldcont; /* Build a fake stack frame or frames */ current_control_frame_pointer = (lispobj *)(unsigned long) (*os_context_register_addr(context, reg_CSP)); if ((lispobj *)(unsigned long) (*os_context_register_addr(context, reg_CFP)) == current_control_frame_pointer) { /* There is a small window during call where the callee's * frame isn't built yet. */ if (lowtag_of(*os_context_register_addr(context, reg_CODE)) == FUN_POINTER_LOWTAG) { /* We have called, but not built the new frame, so * build it for them. */ current_control_frame_pointer[0] = *os_context_register_addr(context, reg_OCFP); current_control_frame_pointer[1] = *os_context_register_addr(context, reg_LRA); current_control_frame_pointer += 8; /* Build our frame on top of it. */ oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP)); } else { /* We haven't yet called, build our frame as if the * partial frame wasn't there. */ oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP)); } } /* We can't tell whether we are still in the caller if it had to * allocate a stack frame due to stack arguments. */ /* This observation provoked some past CMUCL maintainer to ask * "Can anything strange happen during return?" */ else { /* normal case */ oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP)); } current_control_stack_pointer = current_control_frame_pointer + 8; current_control_frame_pointer[0] = oldcont; current_control_frame_pointer[1] = NIL; current_control_frame_pointer[2] = (lispobj)(*os_context_register_addr(context, reg_CODE)); #endif } /* Stores the context for gc to scavange and builds fake stack * frames. */ void fake_foreign_function_call(os_context_t *context) { int context_index; struct thread *thread=arch_os_get_current_thread(); /* context_index incrementing must not be interrupted */ check_blockables_blocked_or_lose(); /* Get current Lisp state from context. */ #ifdef reg_ALLOC dynamic_space_free_pointer = (lispobj *)(unsigned long) (*os_context_register_addr(context, reg_ALLOC)); /* fprintf(stderr,"dynamic_space_free_pointer: %p\n", dynamic_space_free_pointer); */ #if defined(LISP_FEATURE_ALPHA) || defined(LISP_FEATURE_MIPS) if ((long)dynamic_space_free_pointer & 1) { lose("dead in fake_foreign_function_call, context = %x\n", context); } #endif #endif #ifdef reg_BSP current_binding_stack_pointer = (lispobj *)(unsigned long) (*os_context_register_addr(context, reg_BSP)); #endif build_fake_control_stack_frames(thread,context); /* Do dynamic binding of the active interrupt context index * and save the context in the context array. */ context_index = fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread)); if (context_index >= MAX_INTERRUPTS) { lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS); } bind_variable(FREE_INTERRUPT_CONTEXT_INDEX, make_fixnum(context_index + 1),thread); thread->interrupt_contexts[context_index] = context; #ifdef FOREIGN_FUNCTION_CALL_FLAG foreign_function_call_active = 1; #endif } /* blocks all blockable signals. If you are calling from a signal handler, * the usual signal mask will be restored from the context when the handler * finishes. Otherwise, be careful */ void undo_fake_foreign_function_call(os_context_t *context) { struct thread *thread=arch_os_get_current_thread(); /* Block all blockable signals. */ block_blockable_signals(); #ifdef FOREIGN_FUNCTION_CALL_FLAG foreign_function_call_active = 0; #endif /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */ unbind(thread); #ifdef reg_ALLOC /* Put the dynamic space free pointer back into the context. */ *os_context_register_addr(context, reg_ALLOC) = (unsigned long) dynamic_space_free_pointer | (*os_context_register_addr(context, reg_ALLOC) & LOWTAG_MASK); /* ((unsigned long)(*os_context_register_addr(context, reg_ALLOC)) & ~LOWTAG_MASK) | ((unsigned long) dynamic_space_free_pointer & LOWTAG_MASK); */ #endif } /* a handler for the signal caused by execution of a trap opcode * signalling an internal error */ void interrupt_internal_error(os_context_t *context, boolean continuable) { lispobj context_sap; fake_foreign_function_call(context); if (!internal_errors_enabled) { describe_internal_error(context); /* There's no good way to recover from an internal error * before the Lisp error handling mechanism is set up. */ lose("internal error too early in init, can't recover\n"); } /* Allocate the SAP object while the interrupts are still * disabled. */ context_sap = alloc_sap(context); #ifndef LISP_FEATURE_WIN32 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); #endif SHOW("in interrupt_internal_error"); #ifdef QSHOW /* Display some rudimentary debugging information about the * error, so that even if the Lisp error handler gets badly * confused, we have a chance to determine what's going on. */ describe_internal_error(context); #endif funcall2(StaticSymbolFunction(INTERNAL_ERROR), context_sap, continuable ? T : NIL); undo_fake_foreign_function_call(context); /* blocks signals again */ if (continuable) arch_skip_instruction(context); } void interrupt_handle_pending(os_context_t *context) { /* There are three ways we can get here. First, if an interrupt * occurs within pseudo-atomic, it will be deferred, and we'll * trap to here at the end of the pseudo-atomic block. Second, if * the GC (in alloc()) decides that a GC is required, it will set * *GC-PENDING* and pseudo-atomic-interrupted, and alloc() is * always called from within pseudo-atomic, and thus we end up * here again. Third, when calling GC-ON or at the end of a * WITHOUT-GCING, MAYBE-HANDLE-PENDING-GC will trap to here if * there is a pending GC. */ /* Win32 only needs to handle the GC cases (for now?) */ struct thread *thread; /* Punt if in PA section, marking it as interrupted. This can * happenat least if we pick up a GC request while in a * WITHOUT-GCING with an outer PA -- it is not immediately clear * to me that this should/could ever happen, but better safe then * sorry. --NS 2007-05-15 */ if (arch_pseudo_atomic_atomic(context)) { arch_set_pseudo_atomic_interrupted(context); return; } thread = arch_os_get_current_thread(); FSHOW_SIGNAL((stderr, "/entering interrupt_handle_pending\n")); check_blockables_blocked_or_lose(); /* If pseudo_atomic_interrupted is set then the interrupt is going * to be handled now, ergo it's safe to clear it. */ arch_clear_pseudo_atomic_interrupted(context); if (SymbolValue(GC_INHIBIT,thread)==NIL) { #ifdef LISP_FEATURE_SB_THREAD if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) { /* STOP_FOR_GC_PENDING and GC_PENDING are cleared by * the signal handler if it actually stops us. */ sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context); } else #endif if (SymbolValue(GC_PENDING,thread) != NIL) { /* GC_PENDING is cleared in SUB-GC, or if another thread * is doing a gc already we will get a SIG_STOP_FOR_GC and * that will clear it. */ maybe_gc(context); } check_blockables_blocked_or_lose(); } #ifndef LISP_FEATURE_WIN32 /* we may be here only to do the gc stuff, if interrupts are * enabled run the pending handler */ if (SymbolValue(INTERRUPTS_ENABLED,thread) != NIL) { struct interrupt_data *data = thread->interrupt_data; /* There may be no pending handler, because it was only a gc * that had to be executed or because pseudo atomic triggered * twice for a single interrupt. For the interested reader, * that may happen if an interrupt hits after the interrupted * flag is cleared but before pseudo-atomic is set and a * pseudo atomic is interrupted in that interrupt. */ if (data->pending_handler) { /* If we're here as the result of a pseudo-atomic as opposed * to WITHOUT-INTERRUPTS, then INTERRUPT_PENDING is already * NIL, because maybe_defer_handler sets * PSEUDO_ATOMIC_INTERRUPTED only if interrupts are enabled.*/ SetSymbolValue(INTERRUPT_PENDING, NIL, thread); /* restore the saved signal mask from the original signal (the * one that interrupted us during the critical section) into the * os_context for the signal we're currently in the handler for. * This should ensure that when we return from the handler the * blocked signals are unblocked */ sigcopyset(os_context_sigmask_addr(context), &data->pending_mask); sigemptyset(&data->pending_mask); /* This will break on sparc linux: the deferred handler really wants * to be called with a void_context */ run_deferred_handler(data,(void *)context); } } #endif } /* * the two main signal handlers: * interrupt_handle_now(..) * maybe_now_maybe_later(..) * * to which we have added interrupt_handle_now_handler(..). Why? * Well, mostly because the SPARC/Linux platform doesn't quite do * signals the way we want them done. The third argument in the * handler isn't filled in by the kernel properly, so we fix it up * ourselves in the arch_os_get_context(..) function; however, we only * want to do this when we first hit the handler, and not when * interrupt_handle_now(..) is being called from some other handler * (when the fixup will already have been done). -- CSR, 2002-07-23 */ void interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context) { #ifdef FOREIGN_FUNCTION_CALL_FLAG boolean were_in_lisp; #endif union interrupt_handler handler; check_blockables_blocked_or_lose(); #ifndef LISP_FEATURE_WIN32 if (sigismember(&deferrable_sigset,signal)) check_interrupts_enabled_or_lose(context); #endif #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT) /* Under Linux on some architectures, we appear to have to restore the FPU control word from the context, as after the signal is delivered we appear to have a null FPU control word. */ os_restore_fp_control(context); #endif handler = interrupt_handlers[signal]; if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) { return; } #ifdef FOREIGN_FUNCTION_CALL_FLAG were_in_lisp = !foreign_function_call_active; if (were_in_lisp) #endif { fake_foreign_function_call(context); } FSHOW_SIGNAL((stderr, "/entering interrupt_handle_now(%d, info, context)\n", signal)); if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) { /* This can happen if someone tries to ignore or default one * of the signals we need for runtime support, and the runtime * support decides to pass on it. */ lose("no handler for signal %d in interrupt_handle_now(..)\n", signal); } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) { /* Once we've decided what to do about contexts in a * return-elsewhere world (the original context will no longer * be available; should we copy it or was nobody using it anyway?) * then we should convert this to return-elsewhere */ /* CMUCL comment said "Allocate the SAPs while the interrupts * are still disabled.". I (dan, 2003.08.21) assume this is * because we're not in pseudoatomic and allocation shouldn't * be interrupted. In which case it's no longer an issue as * all our allocation from C now goes through a PA wrapper, * but still, doesn't hurt. * * Yeah, but non-gencgc platforms don't really wrap allocation * in PA. MG - 2005-08-29 */ lispobj info_sap,context_sap = alloc_sap(context); info_sap = alloc_sap(info); /* Leave deferrable signals blocked, the handler itself will * allow signals again when it sees fit. */ #ifdef LISP_FEATURE_SB_THREAD { sigset_t unblock; sigemptyset(&unblock); sigaddset(&unblock, SIG_STOP_FOR_GC); #ifdef SIG_RESUME_FROM_GC sigaddset(&unblock, SIG_RESUME_FROM_GC); #endif thread_sigmask(SIG_UNBLOCK, &unblock, 0); } #endif FSHOW_SIGNAL((stderr,"/calling Lisp-level handler\n")); funcall3(handler.lisp, make_fixnum(signal), info_sap, context_sap); } else { FSHOW_SIGNAL((stderr,"/calling C-level handler\n")); #ifndef LISP_FEATURE_WIN32 /* Allow signals again. */ thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); #endif (*handler.c)(signal, info, context); } #ifdef FOREIGN_FUNCTION_CALL_FLAG if (were_in_lisp) #endif { undo_fake_foreign_function_call(context); /* block signals again */ } FSHOW_SIGNAL((stderr, "/returning from interrupt_handle_now(%d, info, context)\n", signal)); } /* This is called at the end of a critical section if the indications * are that some signal was deferred during the section. Note that as * far as C or the kernel is concerned we dealt with the signal * already; we're just doing the Lisp-level processing now that we * put off then */ static void run_deferred_handler(struct interrupt_data *data, void *v_context) { /* The pending_handler may enable interrupts and then another * interrupt may hit, overwrite interrupt_data, so reset the * pending handler before calling it. Trust the handler to finish * with the siginfo before enabling interrupts. */ void (*pending_handler) (int, siginfo_t*, void*)=data->pending_handler; data->pending_handler=0; (*pending_handler)(data->pending_signal,&(data->pending_info), v_context); } #ifndef LISP_FEATURE_WIN32 boolean maybe_defer_handler(void *handler, struct interrupt_data *data, int signal, siginfo_t *info, os_context_t *context) { struct thread *thread=arch_os_get_current_thread(); check_blockables_blocked_or_lose(); if (SymbolValue(INTERRUPT_PENDING,thread) != NIL) lose("interrupt already pending\n"); /* If interrupts are disabled then INTERRUPT_PENDING is set and * not PSEDUO_ATOMIC_INTERRUPTED. This is important for a pseudo * atomic section inside a WITHOUT-INTERRUPTS. */ if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) { store_signal_data_for_later(data,handler,signal,info,context); SetSymbolValue(INTERRUPT_PENDING, T,thread); FSHOW_SIGNAL((stderr, "/maybe_defer_handler(%x,%d),thread=%lu: deferred\n", (unsigned int)handler,signal, (unsigned long)thread->os_thread)); return 1; } /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't * actually use its argument for anything on x86, so this branch * may succeed even when context is null (gencgc alloc()) */ if (arch_pseudo_atomic_atomic(context)) { store_signal_data_for_later(data,handler,signal,info,context); arch_set_pseudo_atomic_interrupted(context); FSHOW_SIGNAL((stderr, "/maybe_defer_handler(%x,%d),thread=%lu: deferred(PA)\n", (unsigned int)handler,signal, (unsigned long)thread->os_thread)); return 1; } FSHOW_SIGNAL((stderr, "/maybe_defer_handler(%x,%d),thread=%lu: not deferred\n", (unsigned int)handler,signal, (unsigned long)thread->os_thread)); return 0; } static void store_signal_data_for_later (struct interrupt_data *data, void *handler, int signal, siginfo_t *info, os_context_t *context) { if (data->pending_handler) lose("tried to overwrite pending interrupt handler %x with %x\n", data->pending_handler, handler); if (!handler) lose("tried to defer null interrupt handler\n"); data->pending_handler = handler; data->pending_signal = signal; if(info) memcpy(&(data->pending_info), info, sizeof(siginfo_t)); FSHOW_SIGNAL((stderr, "/store_signal_data_for_later: signal: %d\n", signal)); if(context) { /* the signal mask in the context (from before we were * interrupted) is copied to be restored when * run_deferred_handler happens. Then the usually-blocked * signals are added to the mask in the context so that we are * running with blocked signals when the handler returns */ sigcopyset(&(data->pending_mask),os_context_sigmask_addr(context)); sigaddset_deferrable(os_context_sigmask_addr(context)); } } static void maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context) { os_context_t *context = arch_os_get_context(&void_context); struct thread *thread = arch_os_get_current_thread(); struct interrupt_data *data = thread->interrupt_data; #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT) os_restore_fp_control(context); #endif if(!maybe_defer_handler(interrupt_handle_now,data,signal,info,context)) interrupt_handle_now(signal, info, context); } static void low_level_interrupt_handle_now(int signal, siginfo_t *info, os_context_t *context) { /* No FP control fixage needed, caller has done that. */ check_blockables_blocked_or_lose(); check_interrupts_enabled_or_lose(context); interrupt_low_level_handlers[signal](signal, info, context); /* No Darwin context fixage needed, caller does that. */ } static void low_level_maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context) { os_context_t *context = arch_os_get_context(&void_context); struct thread *thread = arch_os_get_current_thread(); struct interrupt_data *data = thread->interrupt_data; #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT) os_restore_fp_control(context); #endif if(!maybe_defer_handler(low_level_interrupt_handle_now,data, signal,info,context)) low_level_interrupt_handle_now(signal, info, context); } #endif #ifdef LISP_FEATURE_SB_THREAD void sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context) { os_context_t *context = arch_os_get_context(&void_context); struct thread *thread=arch_os_get_current_thread(); sigset_t ss; if (arch_pseudo_atomic_atomic(context)) { SetSymbolValue(STOP_FOR_GC_PENDING,T,thread); arch_set_pseudo_atomic_interrupted(context); FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred (PA)\n", thread->os_thread)); return; } else if (SymbolValue(GC_INHIBIT,thread) != NIL) { SetSymbolValue(STOP_FOR_GC_PENDING,T,thread); FSHOW_SIGNAL((stderr, "thread=%lu sig_stop_for_gc deferred (*GC-INHIBIT*)\n", thread->os_thread)); return; } /* Not PA and GC not inhibited -- we can stop now. */ /* need the context stored so it can have registers scavenged */ fake_foreign_function_call(context); /* Block everything. */ sigfillset(&ss); thread_sigmask(SIG_BLOCK,&ss,0); /* Not pending anymore. */ SetSymbolValue(GC_PENDING,NIL,thread); SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread); if(thread->state!=STATE_RUNNING) { lose("sig_stop_for_gc_handler: wrong thread state: %ld\n", fixnum_value(thread->state)); } thread->state=STATE_SUSPENDED; FSHOW_SIGNAL((stderr,"thread=%lu suspended\n",thread->os_thread)); sigemptyset(&ss); #if defined(SIG_RESUME_FROM_GC) sigaddset(&ss,SIG_RESUME_FROM_GC); #else sigaddset(&ss,SIG_STOP_FOR_GC); #endif /* It is possible to get SIGCONT (and probably other non-blockable * signals) here. */ #ifdef SIG_RESUME_FROM_GC { int sigret; do { sigwait(&ss, &sigret); } while (sigret != SIG_RESUME_FROM_GC); } #else while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC); #endif FSHOW_SIGNAL((stderr,"thread=%lu resumed\n",thread->os_thread)); if(thread->state!=STATE_RUNNING) { lose("sig_stop_for_gc_handler: wrong thread state on wakeup: %ld\n", fixnum_value(thread->state)); } undo_fake_foreign_function_call(context); } #endif void interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context) { os_context_t *context = arch_os_get_context(&void_context); #if defined(LISP_FEATURE_LINUX) || defined(RESTORE_FP_CONTROL_FROM_CONTEXT) os_restore_fp_control(context); #endif interrupt_handle_now(signal, info, context); } /* manipulate the signal context and stack such that when the handler * returns, it will call function instead of whatever it was doing * previously */ #if (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)) extern int *context_eflags_addr(os_context_t *context); #endif extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs); extern void post_signal_tramp(void); extern void call_into_lisp_tramp(void); void arrange_return_to_lisp_function(os_context_t *context, lispobj function) { #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)) void * fun=native_pointer(function); void *code = &(((struct simple_fun *) fun)->code); #endif /* Build a stack frame showing `interrupted' so that the * user's backtrace makes (as much) sense (as usual) */ /* FIXME: what about restoring fp state? */ /* FIXME: what about restoring errno? */ #ifdef LISP_FEATURE_X86 /* Suppose the existence of some function that saved all * registers, called call_into_lisp, then restored GP registers and * returned. It would look something like this: push ebp mov ebp esp pushfl pushal push $0 push $0 pushl {address of function to call} call 0x8058db0 addl $12,%esp popal popfl leave ret * What we do here is set up the stack that call_into_lisp would * expect to see if it had been called by this code, and frob the * signal context so that signal return goes directly to call_into_lisp, * and when that function (and the lisp function it invoked) returns, * it returns to the second half of this imaginary function which * restores all registers and returns to C * For this to work, the latter part of the imaginary function * must obviously exist in reality. That would be post_signal_tramp */ u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP); #if defined(LISP_FEATURE_DARWIN) u32 *register_save_area = (u32 *)os_validate(0, 0x40); FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: preparing to go to function %x, sp: %x\n", function, sp)); FSHOW_SIGNAL((stderr, "/arrange_return_to_lisp_function: context: %x, &context %x\n", context, &context)); /* 1. os_validate (malloc/mmap) register_save_block * 2. copy register state into register_save_block * 3. put a pointer to register_save_block in a register in the context * 4. set the context's EIP to point to a trampoline which: * a. builds the fake stack frame from the block * b. frees the block * c. calls the function */ *register_save_area = *os_context_pc_addr(context); *(register_save_area + 1) = function; *(register_save_area + 2) = *os_context_register_addr(context,reg_EDI); *(register_save_area + 3) = *os_context_register_addr(context,reg_ESI); *(register_save_area + 4) = *os_context_register_addr(context,reg_EDX); *(register_save_area + 5) = *os_context_register_addr(context,reg_ECX); *(register_save_area + 6) = *os_context_register_addr(context,reg_EBX); *(register_save_area + 7) = *os_context_register_addr(context,reg_EAX); *(register_save_area + 8) = *context_eflags_addr(context); *os_context_pc_addr(context) = (os_context_register_t) call_into_lisp_tramp; *os_context_register_addr(context,reg_ECX) = (os_context_register_t) register_save_area; #else /* return address for call_into_lisp: */ *(sp-15) = (u32)post_signal_tramp; *(sp-14) = function; /* args for call_into_lisp : function*/ *(sp-13) = 0; /* arg array */ *(sp-12) = 0; /* no. args */ /* this order matches that used in POPAD */ *(sp-11)=*os_context_register_addr(context,reg_EDI); *(sp-10)=*os_context_register_addr(context,reg_ESI); *(sp-9)=*os_context_register_addr(context,reg_ESP)-8; /* POPAD ignores the value of ESP: */ *(sp-8)=0; *(sp-7)=*os_context_register_addr(context,reg_EBX); *(sp-6)=*os_context_register_addr(context,reg_EDX); *(sp-5)=*os_context_register_addr(context,reg_ECX); *(sp-4)=*os_context_register_addr(context,reg_EAX); *(sp-3)=*context_eflags_addr(context); *(sp-2)=*os_context_register_addr(context,reg_EBP); *(sp-1)=*os_context_pc_addr(context); #endif #elif defined(LISP_FEATURE_X86_64) u64 *sp=(u64 *)*os_context_register_addr(context,reg_RSP); /* return address for call_into_lisp: */ *(sp-18) = (u64)post_signal_tramp; *(sp-17)=*os_context_register_addr(context,reg_R15); *(sp-16)=*os_context_register_addr(context,reg_R14); *(sp-15)=*os_context_register_addr(context,reg_R13); *(sp-14)=*os_context_register_addr(context,reg_R12); *(sp-13)=*os_context_register_addr(context,reg_R11); *(sp-12)=*os_context_register_addr(context,reg_R10); *(sp-11)=*os_context_register_addr(context,reg_R9); *(sp-10)=*os_context_register_addr(context,reg_R8); *(sp-9)=*os_context_register_addr(context,reg_RDI); *(sp-8)=*os_context_register_addr(context,reg_RSI); /* skip RBP and RSP */ *(sp-7)=*os_context_register_addr(context,reg_RBX); *(sp-6)=*os_context_register_addr(context,reg_RDX); *(sp-5)=*os_context_register_addr(context,reg_RCX); *(sp-4)=*os_context_register_addr(context,reg_RAX); *(sp-3)=*context_eflags_addr(context); *(sp-2)=*os_context_register_addr(context,reg_RBP); *(sp-1)=*os_context_pc_addr(context); *os_context_register_addr(context,reg_RDI) = (os_context_register_t)function; /* function */ *os_context_register_addr(context,reg_RSI) = 0; /* arg. array */ *os_context_register_addr(context,reg_RDX) = 0; /* no. args */ #else struct thread *th=arch_os_get_current_thread(); build_fake_control_stack_frames(th,context); #endif #ifdef LISP_FEATURE_X86 #if !defined(LISP_FEATURE_DARWIN) *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp; *os_context_register_addr(context,reg_ECX) = 0; *os_context_register_addr(context,reg_EBP) = (os_context_register_t)(sp-2); #ifdef __NetBSD__ *os_context_register_addr(context,reg_UESP) = (os_context_register_t)(sp-15); #else *os_context_register_addr(context,reg_ESP) = (os_context_register_t)(sp-15); #endif /* __NETBSD__ */ #endif /* LISP_FEATURE_DARWIN */ #elif defined(LISP_FEATURE_X86_64) *os_context_pc_addr(context) = (os_context_register_t)call_into_lisp; *os_context_register_addr(context,reg_RCX) = 0; *os_context_register_addr(context,reg_RBP) = (os_context_register_t)(sp-2); *os_context_register_addr(context,reg_RSP) = (os_context_register_t)(sp-18); #else /* this much of the calling convention is common to all non-x86 ports */ *os_context_pc_addr(context) = (os_context_register_t)(unsigned long)code; *os_context_register_addr(context,reg_NARGS) = 0; *os_context_register_addr(context,reg_LIP) = (os_context_register_t)(unsigned long)code; *os_context_register_addr(context,reg_CFP) = (os_context_register_t)(unsigned long)current_control_frame_pointer; #endif #ifdef ARCH_HAS_NPC_REGISTER *os_context_npc_addr(context) = 4 + *os_context_pc_addr(context); #endif #ifdef LISP_FEATURE_SPARC *os_context_register_addr(context,reg_CODE) = (os_context_register_t)(fun + FUN_POINTER_LOWTAG); #endif } #ifdef LISP_FEATURE_SB_THREAD /* FIXME: this function can go away when all lisp handlers are invoked * via arrange_return_to_lisp_function. */ void interrupt_thread_handler(int num, siginfo_t *info, void *v_context) { os_context_t *context = (os_context_t*)arch_os_get_context(&v_context); /* let the handler enable interrupts again when it sees fit */ sigaddset_deferrable(os_context_sigmask_addr(context)); arrange_return_to_lisp_function(context, StaticSymbolFunction(RUN_INTERRUPTION)); } #endif /* KLUDGE: Theoretically the approach we use for undefined alien * variables should work for functions as well, but on PPC/Darwin * we get bus error at bogus addresses instead, hence this workaround, * that has the added benefit of automatically discriminating between * functions and variables. */ void undefined_alien_function(void) { funcall0(StaticSymbolFunction(UNDEFINED_ALIEN_FUNCTION_ERROR)); } boolean handle_guard_page_triggered(os_context_t *context,os_vm_address_t addr) { struct thread *th=arch_os_get_current_thread(); /* note the os_context hackery here. When the signal handler returns, * it won't go back to what it was doing ... */ if(addr >= CONTROL_STACK_GUARD_PAGE(th) && addr < CONTROL_STACK_GUARD_PAGE(th) + os_vm_page_size) { /* We hit the end of the control stack: disable guard page * protection so the error handler has some headroom, protect the * previous page so that we can catch returns from the guard page * and restore it. */ protect_control_stack_guard_page(0); protect_control_stack_return_guard_page(1); arrange_return_to_lisp_function (context, StaticSymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR)); return 1; } else if(addr >= CONTROL_STACK_RETURN_GUARD_PAGE(th) && addr < CONTROL_STACK_RETURN_GUARD_PAGE(th) + os_vm_page_size) { /* We're returning from the guard page: reprotect it, and * unprotect this one. This works even if we somehow missed * the return-guard-page, and hit it on our way to new * exhaustion instead. */ protect_control_stack_guard_page(1); protect_control_stack_return_guard_page(0); return 1; } else if (addr >= undefined_alien_address && addr < undefined_alien_address + os_vm_page_size) { arrange_return_to_lisp_function (context, StaticSymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR)); return 1; } else return 0; } /* * noise to install handlers */ #ifndef LISP_FEATURE_WIN32 /* In Linux 2.4 synchronous signals (sigtrap & co) can be delivered if * they are blocked, in Linux 2.6 the default handler is invoked * instead that usually coredumps. One might hastily think that adding * SA_NODEFER helps, but until ~2.6.13 if SA_NODEFER is specified then * the whole sa_mask is ignored and instead of not adding the signal * in question to the mask. That means if it's not blockable the * signal must be unblocked at the beginning of signal handlers. * * It turns out that NetBSD's SA_NODEFER doesn't DTRT in a different * way: if SA_NODEFER is set and the signal is in sa_mask, the signal * will be unblocked in the sigmask during the signal handler. -- RMK * X-mas day, 2005 */ static volatile int sigaction_nodefer_works = -1; #define SA_NODEFER_TEST_BLOCK_SIGNAL SIGABRT #define SA_NODEFER_TEST_KILL_SIGNAL SIGUSR1 static void sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context) { sigset_t empty, current; int i; sigemptyset(&empty); thread_sigmask(SIG_BLOCK, &empty, ¤t); /* There should be exactly two blocked signals: the two we added * to sa_mask when setting up the handler. NetBSD doesn't block * the signal we're handling when SA_NODEFER is set; Linux before * 2.6.13 or so also doesn't block the other signal when * SA_NODEFER is set. */ for(i = 1; i < NSIG; i++) if (sigismember(¤t, i) != (((i == SA_NODEFER_TEST_BLOCK_SIGNAL) || (i == signal)) ? 1 : 0)) { FSHOW_SIGNAL((stderr, "SA_NODEFER doesn't work, signal %d\n", i)); sigaction_nodefer_works = 0; } if (sigaction_nodefer_works == -1) sigaction_nodefer_works = 1; } static void see_if_sigaction_nodefer_works(void) { struct sigaction sa, old_sa; sa.sa_flags = SA_SIGINFO | SA_NODEFER; sa.sa_sigaction = sigaction_nodefer_test_handler; sigemptyset(&sa.sa_mask); sigaddset(&sa.sa_mask, SA_NODEFER_TEST_BLOCK_SIGNAL); sigaddset(&sa.sa_mask, SA_NODEFER_TEST_KILL_SIGNAL); sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &sa, &old_sa); /* Make sure no signals are blocked. */ { sigset_t empty; sigemptyset(&empty); thread_sigmask(SIG_SETMASK, &empty, 0); } kill(getpid(), SA_NODEFER_TEST_KILL_SIGNAL); while (sigaction_nodefer_works == -1); sigaction(SA_NODEFER_TEST_KILL_SIGNAL, &old_sa, NULL); } #undef SA_NODEFER_TEST_BLOCK_SIGNAL #undef SA_NODEFER_TEST_KILL_SIGNAL static void unblock_me_trampoline(int signal, siginfo_t *info, void *void_context) { sigset_t unblock; sigemptyset(&unblock); sigaddset(&unblock, signal); thread_sigmask(SIG_UNBLOCK, &unblock, 0); interrupt_handle_now_handler(signal, info, void_context); } static void low_level_unblock_me_trampoline(int signal, siginfo_t *info, void *void_context) { sigset_t unblock; sigemptyset(&unblock); sigaddset(&unblock, signal); thread_sigmask(SIG_UNBLOCK, &unblock, 0); (*interrupt_low_level_handlers[signal])(signal, info, void_context); } void undoably_install_low_level_interrupt_handler (int signal, interrupt_handler_t handler) { struct sigaction sa; if (0 > signal || signal >= NSIG) { lose("bad signal number %d\n", signal); } if (ARE_SAME_HANDLER(handler, SIG_DFL)) sa.sa_sigaction = handler; else if (sigismember(&deferrable_sigset,signal)) sa.sa_sigaction = low_level_maybe_now_maybe_later; /* The use of a trampoline appears to break the arch_os_get_context() workaround for SPARC/Linux. For now, don't use the trampoline (and so be vulnerable to the problems that SA_NODEFER is meant to solve. */ #if !(defined(LISP_FEATURE_SPARC) && defined(LISP_FEATURE_LINUX)) else if (!sigaction_nodefer_works && !sigismember(&blockable_sigset, signal)) sa.sa_sigaction = low_level_unblock_me_trampoline; #endif else sa.sa_sigaction = handler; sigcopyset(&sa.sa_mask, &blockable_sigset); sa.sa_flags = SA_SIGINFO | SA_RESTART | (sigaction_nodefer_works ? SA_NODEFER : 0); #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK if((signal==SIG_MEMORY_FAULT) #ifdef SIG_INTERRUPT_THREAD || (signal==SIG_INTERRUPT_THREAD) #endif ) sa.sa_flags |= SA_ONSTACK; #endif sigaction(signal, &sa, NULL); interrupt_low_level_handlers[signal] = (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler); } #endif /* This is called from Lisp. */ unsigned long install_handler(int signal, void handler(int, siginfo_t*, void*)) { #ifndef LISP_FEATURE_WIN32 struct sigaction sa; sigset_t old, new; union interrupt_handler oldhandler; FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal)); sigemptyset(&new); sigaddset(&new, signal); thread_sigmask(SIG_BLOCK, &new, &old); FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%x\n", (unsigned int)interrupt_low_level_handlers[signal])); if (interrupt_low_level_handlers[signal]==0) { if (ARE_SAME_HANDLER(handler, SIG_DFL) || ARE_SAME_HANDLER(handler, SIG_IGN)) sa.sa_sigaction = handler; else if (sigismember(&deferrable_sigset, signal)) sa.sa_sigaction = maybe_now_maybe_later; else if (!sigaction_nodefer_works && !sigismember(&blockable_sigset, signal)) sa.sa_sigaction = unblock_me_trampoline; else sa.sa_sigaction = interrupt_handle_now_handler; sigcopyset(&sa.sa_mask, &blockable_sigset); sa.sa_flags = SA_SIGINFO | SA_RESTART | (sigaction_nodefer_works ? SA_NODEFER : 0); sigaction(signal, &sa, NULL); } oldhandler = interrupt_handlers[signal]; interrupt_handlers[signal].c = handler; thread_sigmask(SIG_SETMASK, &old, 0); FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal)); return (unsigned long)oldhandler.lisp; #else /* Probably-wrong Win32 hack */ return 0; #endif } void interrupt_init(void) { #ifndef LISP_FEATURE_WIN32 int i; SHOW("entering interrupt_init()"); see_if_sigaction_nodefer_works(); sigemptyset(&deferrable_sigset); sigemptyset(&blockable_sigset); sigaddset_deferrable(&deferrable_sigset); sigaddset_blockable(&blockable_sigset); /* Set up high level handler information. */ for (i = 0; i < NSIG; i++) { interrupt_handlers[i].c = /* (The cast here blasts away the distinction between * SA_SIGACTION-style three-argument handlers and * signal(..)-style one-argument handlers, which is OK * because it works to call the 1-argument form where the * 3-argument form is expected.) */ (void (*)(int, siginfo_t*, void*))SIG_DFL; } SHOW("returning from interrupt_init()"); #endif } #ifndef LISP_FEATURE_WIN32 int siginfo_code(siginfo_t *info) { return info->si_code; } os_vm_address_t current_memory_fault_address; void lisp_memory_fault_error(os_context_t *context, os_vm_address_t addr) { /* FIXME: This is lossy: if we get another memory fault (eg. from * another thread) before lisp has read this, we lose the information. * However, since this is mostly informative, we'll live with that for * now -- some address is better then no address in this case. */ current_memory_fault_address = addr; arrange_return_to_lisp_function(context, StaticSymbolFunction(MEMORY_FAULT_ERROR)); } #endif static void unhandled_trap_error(os_context_t *context) { lispobj context_sap; fake_foreign_function_call(context); context_sap = alloc_sap(context); #ifndef LISP_FEATURE_WIN32 thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); #endif funcall1(StaticSymbolFunction(UNHANDLED_TRAP_ERROR), context_sap); lose("UNHANDLED-TRAP-ERROR fell through"); } /* Common logic for trapping instructions. How we actually handle each * case is highly architecture dependent, but the overall shape is * this. */ void handle_trap(os_context_t *context, int trap) { switch(trap) { case trap_PendingInterrupt: FSHOW((stderr, "/\n")); arch_skip_instruction(context); interrupt_handle_pending(context); break; case trap_Error: case trap_Cerror: FSHOW((stderr, "/\n", trap)); interrupt_internal_error(context, trap==trap_Cerror); break; case trap_Breakpoint: arch_handle_breakpoint(context); break; case trap_FunEndBreakpoint: arch_handle_fun_end_breakpoint(context); break; #ifdef trap_AfterBreakpoint case trap_AfterBreakpoint: arch_handle_after_breakpoint(context); break; #endif #ifdef trap_SingleStepAround case trap_SingleStepAround: case trap_SingleStepBefore: arch_handle_single_step_trap(context, trap); break; #endif case trap_Halt: fake_foreign_function_call(context); lose("%%PRIMITIVE HALT called; the party is over.\n"); default: unhandled_trap_error(context); } }