X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Finterrupt.c;h=6a5205337553a916b33e090ed1e11592205136a4;hb=7fb597b585fc715537ea644f7d84440eca217ca1;hp=c63083122f0460b913f0c784c7de8f0a5543d85a;hpb=e365f2f7a9c66d307b48fee70778f4eaa84bdcc0;p=sbcl.git diff --git a/src/runtime/interrupt.c b/src/runtime/interrupt.c index c630831..6a52053 100644 --- a/src/runtime/interrupt.c +++ b/src/runtime/interrupt.c @@ -13,14 +13,47 @@ * 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 "sbcl.h" #include "os.h" #include "interrupt.h" #include "globals.h" @@ -33,8 +66,20 @@ #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); +boolean interrupt_maybe_gc_int(int signal, siginfo_t *info, void *v_context); -void sigaddset_blockable(sigset_t *s) +void +sigaddset_deferrable(sigset_t *s) { sigaddset(s, SIGHUP); sigaddset(s, SIGINT); @@ -42,7 +87,6 @@ void sigaddset_blockable(sigset_t *s) sigaddset(s, SIGPIPE); sigaddset(s, SIGALRM); sigaddset(s, SIGURG); - sigaddset(s, SIGFPE); sigaddset(s, SIGTSTP); sigaddset(s, SIGCHLD); sigaddset(s, SIGIO); @@ -53,6 +97,53 @@ void sigaddset_blockable(sigset_t *s) sigaddset(s, SIGWINCH); sigaddset(s, SIGUSR1); sigaddset(s, SIGUSR2); +#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 + 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() +{ +#ifndef 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 +} + +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 ( +#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64) + (!foreign_function_call_active) && +#endif + 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 @@ -62,64 +153,63 @@ void sigaddset_blockable(sigset_t *s) * becomes 'yes'.) */ boolean internal_errors_enabled = 0; -struct interrupt_data * global_interrupt_data; +#ifndef LISP_FEATURE_WIN32 +static void (*interrupt_low_level_handlers[NSIG]) (int, siginfo_t*, void*); +#endif +union interrupt_handler interrupt_handlers[NSIG]; -/* 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 interrupt_handle_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 */ +/* 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 +} -boolean maybe_gc_pending = 0; /* * utility routines used by various signal handlers */ -void +static void build_fake_control_stack_frames(struct thread *th,os_context_t *context) { -#ifndef LISP_FEATURE_X86 - +#ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK + lispobj oldcont; /* Build a fake stack frame or frames */ current_control_frame_pointer = - (lispobj *)(*os_context_register_addr(context, reg_CSP)); - if ((lispobj *)(*os_context_register_addr(context, reg_CFP)) - == 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) { + == 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); + *os_context_register_addr(context, reg_OCFP); current_control_frame_pointer[1] = - *os_context_register_addr(context, reg_LRA); + *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)); @@ -144,29 +234,36 @@ build_fake_control_stack_frames(struct thread *th,os_context_t *context) 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)); + (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 *)(*os_context_register_addr(context, reg_ALLOC)); -#ifdef alpha + (lispobj *)(unsigned long) + (*os_context_register_addr(context, reg_ALLOC)); +#if defined(LISP_FEATURE_ALPHA) if ((long)dynamic_space_free_pointer & 1) { - lose("dead in fake_foreign_function_call, context = %x", context); + lose("dead in fake_foreign_function_call, context = %x\n", context); } #endif #endif #ifdef reg_BSP current_binding_stack_pointer = - (lispobj *)(*os_context_register_addr(context, reg_BSP)); + (lispobj *)(unsigned long) + (*os_context_register_addr(context, reg_BSP)); #endif build_fake_control_stack_frames(thread,context); @@ -174,14 +271,14 @@ fake_foreign_function_call(os_context_t *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)); - + fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread)); + if (context_index >= MAX_INTERRUPTS) { - lose("maximum interrupt nesting depth (%d) exceeded", MAX_INTERRUPTS); + lose("maximum interrupt nesting depth (%d) exceeded\n", MAX_INTERRUPTS); } bind_variable(FREE_INTERRUPT_CONTEXT_INDEX, - make_fixnum(context_index + 1),thread); + make_fixnum(context_index + 1),thread); thread->interrupt_contexts[context_index] = context; @@ -189,26 +286,20 @@ fake_foreign_function_call(os_context_t *context) foreign_function_call_active = 1; } +/* 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. */ - sigset_t block; - sigemptyset(&block); - sigaddset_blockable(&block); - sigprocmask(SIG_BLOCK, &block, 0); + block_blockable_signals(); /* going back into Lisp */ foreign_function_call_active = 0; - /* Undo dynamic binding. */ - /* ### Do I really need to unbind_to_here()? */ - /* FIXME: Is this to undo the binding of - * FREE_INTERRUPT_CONTEXT_INDEX? If so, we should say so. And - * perhaps yes, unbind_to_here() really would be clearer and less - * fragile.. */ - /* dan (2001.08.10) thinks the above supposition is probably correct */ + /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */ unbind(thread); #ifdef reg_ALLOC @@ -222,48 +313,41 @@ undo_fake_foreign_function_call(os_context_t *context) * signalling an internal error */ void interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context, - boolean continuable) + boolean continuable) { - lispobj context_sap = 0; + 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. */ - if (internal_errors_enabled) { - context_sap = alloc_sap(context); - } + context_sap = alloc_sap(context); - sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); +#ifndef LISP_FEATURE_WIN32 + thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); +#endif - if (internal_errors_enabled) { - SHOW("in interrupt_internal_error"); -#if 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); + 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(SymbolFunction(INTERNAL_ERROR), context_sap, - continuable ? T : NIL); - } else { - 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"); - } - undo_fake_foreign_function_call(context); - if (continuable) { - arch_skip_instruction(context); - } -} + funcall2(SymbolFunction(INTERNAL_ERROR), context_sap, + continuable ? T : NIL); -/* This function handles pending interrupts. Note that in C/kernel - * terms we dealt with the signal already; we just haven't decided - * whether to call a Lisp handler or do a GC or something like that. - * If it helps, you can think of pending_{signal,mask,info} as a - * one-element queue of signals that we have acknowledged but not - * processed */ + undo_fake_foreign_function_call(context); /* blocks signals again */ + if (continuable) + arch_skip_instruction(context); +} void interrupt_handle_pending(os_context_t *context) @@ -271,67 +355,73 @@ interrupt_handle_pending(os_context_t *context) struct thread *thread; struct interrupt_data *data; -#ifndef __i386__ - boolean were_in_lisp = !foreign_function_call_active; -#endif -#ifdef LISP_FEATURE_SB_THREAD - while(stop_the_world) kill(getpid(),SIGSTOP); -#endif + check_blockables_blocked_or_lose(); + thread=arch_os_get_current_thread(); data=thread->interrupt_data; - SetSymbolValue(INTERRUPT_PENDING, NIL,thread); - if (maybe_gc_pending) { -#ifndef __i386__ - if (were_in_lisp) +#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64) + /* 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); #endif - { - fake_foreign_function_call(context); - } - funcall0(SymbolFunction(MAYBE_GC)); -#ifndef __i386__ - if (were_in_lisp) + + if (SymbolValue(GC_INHIBIT,thread)==NIL) { +#ifdef LISP_FEATURE_SB_THREAD + if (SymbolValue(STOP_FOR_GC_PENDING,thread) != NIL) { + /* another thread has already initiated a gc, this attempt + * might as well be cancelled */ + SetSymbolValue(GC_PENDING,NIL,thread); + SetSymbolValue(STOP_FOR_GC_PENDING,NIL,thread); + sig_stop_for_gc_handler(SIG_STOP_FOR_GC,NULL,context); + } else #endif - { - undo_fake_foreign_function_call(context); + 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. */ + interrupt_maybe_gc_int(0,NULL,context); } + check_blockables_blocked_or_lose(); } - /* FIXME: This isn't very clear. It would be good to reverse - * engineer it and rewrite the code more clearly, or write a clear - * explanation of what's going on in the comments, or both. - * - * WHN's question 1a: How come we unconditionally copy from - * pending_mask into the context, and then test whether - * pending_signal is set? - * - * WHN's question 1b: If pending_signal wasn't set, how could - * pending_mask be valid? - * - * Dan Barlow's reply (sbcl-devel 2001-03-13): And the answer is - - * or appears to be - because interrupt_maybe_gc set it that way - * (look in the #ifndef __i386__ bit). We can't GC during a - * pseudo-atomic, so we set maybe_gc_pending=1 and - * arch_set_pseudo_atomic_interrupted(..) When we come out of - * pseudo_atomic we're marked as interrupted, so we call - * interrupt_handle_pending, which does the GC using the pending - * context (it needs a context so that it has registers to use as - * GC roots) then notices there's no actual interrupt handler to - * call, so doesn't. That's the second question [1b] answered, - * anyway. Why we still need to copy the pending_mask into the - * context given that we're now done with the context anyway, I - * couldn't say. */ -#if 0 - memcpy(os_context_sigmask_addr(context), &pending_mask, - 4 /* sizeof(sigset_t) */ ); -#endif - sigemptyset(&data->pending_mask); - if (data->pending_signal) { - int signal = data->pending_signal; - siginfo_t info; - memcpy(&info, &data->pending_info, sizeof(siginfo_t)); - data->pending_signal = 0; - interrupt_handle_now(signal, &info, context); + /* we may be here only to do the gc stuff, if interrupts are + * enabled run the pending handler */ + if (!((SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) || + ( +#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64) + (!foreign_function_call_active) && +#endif + arch_pseudo_atomic_atomic(context)))) { + + /* 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 pseduo-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); + +#ifndef LISP_FEATURE_WIN32 + /* 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); +#endif + /* This will break on sparc linux: the deferred handler really wants + * to be called with a void_context */ + run_deferred_handler(data,(void *)context); + } } } @@ -354,25 +444,29 @@ void interrupt_handle_now(int signal, siginfo_t *info, void *void_context) { os_context_t *context = (os_context_t*)void_context; - struct thread *thread=arch_os_get_current_thread(); -#ifndef __i386__ +#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64) 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 #ifdef LISP_FEATURE_LINUX /* 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 = thread->interrupt_data->interrupt_handlers[signal]; +#endif + handler = interrupt_handlers[signal]; if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) { - return; + return; } - -#ifndef __i386__ + +#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64) were_in_lisp = !foreign_function_call_active; if (were_in_lisp) #endif @@ -380,77 +474,170 @@ interrupt_handle_now(int signal, siginfo_t *info, void *void_context) fake_foreign_function_call(context); } -#ifdef QSHOW_SIGNALS - FSHOW((stderr, - "/entering interrupt_handle_now(%d, info, context)\n", - signal)); -#endif + 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(..)", signal); + /* 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 */ - /* Allocate the SAPs while the interrupts are still disabled. - * (FIXME: Why? This is the way it was done in CMU CL, and it - * even had the comment noting that this is the way it was - * done, but no motivation..) */ lispobj info_sap,context_sap = alloc_sap(context); info_sap = alloc_sap(info); - /* Allow signals again. */ - sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); - -#ifdef QSHOW_SIGNALS - SHOW("calling Lisp-level handler"); + /* 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); + 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); + make_fixnum(signal), + info_sap, + context_sap); } else { -#ifdef QSHOW_SIGNALS - SHOW("calling C-level handler"); -#endif + FSHOW_SIGNAL((stderr,"/calling C-level handler\n")); +#ifndef LISP_FEATURE_WIN32 /* Allow signals again. */ - sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); - + thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); +#endif + (*handler.c)(signal, info, void_context); } -#ifndef __i386__ +#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64) if (were_in_lisp) #endif { - undo_fake_foreign_function_call(context); + undo_fake_foreign_function_call(context); /* block signals again */ } -#ifdef QSHOW_SIGNALS - FSHOW((stderr, - "/returning from interrupt_handle_now(%d, info, context)\n", - signal)); + 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 ( +#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64) + /* FIXME: this foreign_function_call_active test is dubious at + * best. If a foreign call is made in a pseudo atomic section + * (?) or more likely a pseudo atomic section is in a foreign + * call then an interrupt is executed immediately. Maybe it + * has to do with C code not maintaining pseudo atomic + * properly. MG - 2005-08-10 */ + (!foreign_function_call_active) && #endif + 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, int signal, - siginfo_t *info, os_context_t *context) +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; - memcpy(&(data->pending_info), info, sizeof(siginfo_t)); - memcpy(&(data->pending_mask), - os_context_sigmask_addr(context), - sizeof(sigset_t)); - sigaddset_blockable(os_context_sigmask_addr(context)); + if(info) + memcpy(&(data->pending_info), info, sizeof(siginfo_t)); + 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) { @@ -459,288 +646,615 @@ maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context) struct interrupt_data *data=thread->interrupt_data; #ifdef LISP_FEATURE_LINUX os_restore_fp_control(context); -#endif - /* see comments at top of code/signal.lisp for what's going on here - * with INTERRUPTS_ENABLED/INTERRUPT_HANDLE_NOW - */ - if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) { - store_signal_data_for_later(data,signal,info,context); - SetSymbolValue(INTERRUPT_PENDING, T,thread); - } else if ( -#ifndef __i386__ - (!foreign_function_call_active) && #endif - arch_pseudo_atomic_atomic(context)) { - store_signal_data_for_later(data,signal,info,context); - arch_set_pseudo_atomic_interrupted(context); + if(maybe_defer_handler(interrupt_handle_now,data,signal,info,context)) + return; + interrupt_handle_now(signal, info, context); +#ifdef LISP_FEATURE_DARWIN + /* Work around G5 bug */ + DARWIN_FIX_CONTEXT(context); +#endif +} + +static void +low_level_interrupt_handle_now(int signal, siginfo_t *info, void *void_context) +{ + os_context_t *context = (os_context_t*)void_context; + +#ifdef LISP_FEATURE_LINUX + os_restore_fp_control(context); +#endif + check_blockables_blocked_or_lose(); + check_interrupts_enabled_or_lose(context); + interrupt_low_level_handlers[signal](signal, info, void_context); +#ifdef LISP_FEATURE_DARWIN + /* Work around G5 bug */ + DARWIN_FIX_CONTEXT(context); +#endif +} + +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; +#ifdef LISP_FEATURE_LINUX + os_restore_fp_control(context); +#endif + if(maybe_defer_handler(low_level_interrupt_handle_now,data, + signal,info,context)) + return; + low_level_interrupt_handle_now(signal, info, context); +#ifdef LISP_FEATURE_DARWIN + /* Work around G5 bug */ + DARWIN_FIX_CONTEXT(context); +#endif +} +#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) || + SymbolValue(GC_INHIBIT,thread) != NIL)) { + SetSymbolValue(STOP_FOR_GC_PENDING,T,thread); + if (SymbolValue(GC_INHIBIT,thread) == NIL) + arch_set_pseudo_atomic_interrupted(context); + FSHOW_SIGNAL((stderr,"thread=%lu sig_stop_for_gc deferred\n", + thread->os_thread)); } else { - interrupt_handle_now(signal, info, context); + /* need the context stored so it can have registers scavenged */ + fake_foreign_function_call(context); + + sigfillset(&ss); /* Block everything. */ + thread_sigmask(SIG_BLOCK,&ss,0); + + 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); sigaddset(&ss,SIG_STOP_FOR_GC); + /* It is possible to get SIGCONT (and probably other + * non-blockable signals) here. */ + while (sigwaitinfo(&ss,0) != SIG_STOP_FOR_GC); + 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); interrupt_handle_now(signal, info, context); +#ifdef LISP_FEATURE_DARWIN + DARWIN_FIX_CONTEXT(context); +#endif } /* * stuff to detect and handle hitting the GC trigger */ -#ifndef LISP_FEATURE_GENCGC +#ifndef LISP_FEATURE_GENCGC /* since GENCGC has its own way to record trigger */ static boolean gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context) { if (current_auto_gc_trigger == NULL) - return 0; + return 0; else{ - void *badaddr=arch_get_bad_addr(signal,info,context); - return (badaddr >= (void *)current_auto_gc_trigger && - badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE)); + void *badaddr=arch_get_bad_addr(signal,info,context); + return (badaddr >= (void *)current_auto_gc_trigger && + badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE)); } } #endif -/* and similarly for the control stack guard page */ +/* 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 -boolean handle_control_stack_guard_triggered(os_context_t *context,void *addr) +extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs); +extern void post_signal_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); + + /* 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); + +#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(); - /* note the os_context hackery here. When the signal handler returns, - * it won't go back to what it was doing ... */ - if(addr>=(void *)CONTROL_STACK_GUARD_PAGE(th) && - addr<(void *)(CONTROL_STACK_GUARD_PAGE(th)+os_vm_page_size)) { - void *fun; - void *code; - /* fprintf(stderr, "hit end of control stack\n"); */ - /* we hit the end of the control stack. disable protection - * temporarily so the error handler has some headroom */ - protect_control_stack_guard_page(th->pid,0L); - - fun = (void *) - native_pointer((lispobj) SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR)); - code = &(((struct simple_fun *) fun)->code); - - /* Build a stack frame showing `interrupted' so that the - * user's backtrace makes (as much) sense (as usual) */ - build_fake_control_stack_frames(th,context); - /* signal handler will "return" to this error-causing function */ - *os_context_pc_addr(context) = code; + build_fake_control_stack_frames(th,context); +#endif + #ifdef LISP_FEATURE_X86 - *os_context_register_addr(context,reg_ECX) = 0; + *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 +#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_register_addr(context,reg_NARGS) = 0; - *os_context_register_addr(context,reg_LIP) = code; - *os_context_register_addr(context,reg_CFP) = - current_control_frame_pointer; + /* 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); + *os_context_npc_addr(context) = + 4 + *os_context_pc_addr(context); #endif #ifdef LISP_FEATURE_SPARC - /* Bletch. This is a feature of the SPARC calling convention, - which sadly I'm not going to go into in large detail here, - as I don't know it well enough. Suffice to say that if the - line + *os_context_register_addr(context,reg_CODE) = + (os_context_register_t)(fun + FUN_POINTER_LOWTAG); +#endif +} + +#ifdef LISP_FEATURE_SB_THREAD - (INST MOVE CODE-TN FUNCTION) +/* 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, SymbolFunction(RUN_INTERRUPTION)); +} - in compiler/sparc/call.lisp is changed, then this bit can - probably go away. -- CSR, 2002-07-24 */ - *os_context_register_addr(context,reg_CODE) = - fun + FUN_POINTER_LOWTAG; #endif - return 1; + +/* 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() { + funcall0(SymbolFunction(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, SymbolFunction(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, SymbolFunction(UNDEFINED_ALIEN_VARIABLE_ERROR)); + return 1; } else return 0; } -#ifndef LISP_FEATURE_X86 -/* This function gets called from the SIGSEGV (for e.g. Linux or +#ifndef LISP_FEATURE_GENCGC +/* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, & * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check * whether the signal was due to treading on the mprotect()ed zone - * and if so, arrange for a GC to happen. */ +extern unsigned long bytes_consed_between_gcs; /* gc-common.c */ + boolean interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context) { os_context_t *context=(os_context_t *) void_context; - if (!foreign_function_call_active -#ifndef LISP_FEATURE_GENCGC - /* nb: GENCGC on non-x86? I really don't think so. This - * happens every time */ - && gc_trigger_hit(signal, info, context) -#endif - ) { -#ifndef LISP_FEATURE_GENCGC - clear_auto_gc_trigger(); -#endif - - if (arch_pseudo_atomic_atomic(context)) { - /* don't GC during an atomic operation. Instead, copy the - * signal mask somewhere safe. interrupt_handle_pending - * will detect pending_signal==0 and know to do a GC with the - * signal context instead of calling a Lisp-level handler */ - maybe_gc_pending = 1; - if (pending_signal == 0) { - /* FIXME: This copy-pending_mask-then-sigaddset_blockable - * idiom occurs over and over. It should be factored out - * into a function with a descriptive name. */ - memcpy(&pending_mask, - os_context_sigmask_addr(context), - sizeof(sigset_t)); - sigaddset_blockable(os_context_sigmask_addr(context)); - } - arch_set_pseudo_atomic_interrupted(context); - } - else { - lispobj *old_free_space=current_dynamic_space; - fake_foreign_function_call(context); - funcall0(SymbolFunction(MAYBE_GC)); - undo_fake_foreign_function_call(context); - if(current_dynamic_space==old_free_space) - /* MAYBE-GC (as the name suggest) might not. If it - * doesn't, it won't reset the GC trigger either, so we - * have to do it ourselves. Put it near the end of - * dynamic space so we're not running into it continually - */ - set_auto_gc_trigger(DYNAMIC_SPACE_SIZE - -(u32)os_vm_page_size); - } - return 1; - } else { - return 0; + if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){ + struct thread *thread=arch_os_get_current_thread(); + clear_auto_gc_trigger(); + /* Don't flood the system with interrupts if the need to gc is + * already noted. This can happen for example when SUB-GC + * allocates or after a gc triggered in a WITHOUT-GCING. */ + if (SymbolValue(GC_PENDING,thread) == NIL) { + if (SymbolValue(GC_INHIBIT,thread) == NIL) { + if (arch_pseudo_atomic_atomic(context)) { + /* set things up so that GC happens when we finish + * the PA section */ + SetSymbolValue(GC_PENDING,T,thread); + arch_set_pseudo_atomic_interrupted(context); + } else { + interrupt_maybe_gc_int(signal,info,void_context); + } + } else { + SetSymbolValue(GC_PENDING,T,thread); + } + } + return 1; } + return 0; } + +#endif + +/* this is also used by gencgc, in alloc() */ +boolean +interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context) +{ + os_context_t *context=(os_context_t *) void_context; +#ifndef LISP_FEATURE_WIN32 + struct thread *thread=arch_os_get_current_thread(); +#endif + + fake_foreign_function_call(context); + + /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in + * which case we will be running with no gc trigger barrier + * thing for a while. But it shouldn't be long until the end + * of WITHOUT-GCING. + * + * FIXME: It would be good to protect the end of dynamic space + * and signal a storage condition from there. + */ + + /* Restore the signal mask from the interrupted context before + * calling into Lisp if interrupts are enabled. Why not always? + * + * Suppose there is a WITHOUT-INTERRUPTS block far, far out. If an + * interrupt hits while in SUB-GC, it is deferred and the + * os_context_sigmask of that interrupt is set to block further + * deferrable interrupts (until the first one is + * handled). Unfortunately, that context refers to this place and + * when we return from here the signals will not be blocked. + * + * A kludgy alternative is to propagate the sigmask change to the + * outer context. + */ +#ifndef LISP_FEATURE_WIN32 + if(SymbolValue(INTERRUPTS_ENABLED,thread)!=NIL) + thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0); +#ifdef LISP_FEATURE_SB_THREAD + else { + sigset_t new; + sigemptyset(&new); + sigaddset(&new,SIG_STOP_FOR_GC); + thread_sigmask(SIG_UNBLOCK,&new,0); + } +#endif #endif + funcall0(SymbolFunction(SUB_GC)); + + undo_fake_foreign_function_call(context); + return 1; +} + /* * noise to install handlers */ -/* SBCL used to have code to restore signal handlers on exit, which - * has been removed from the threaded version until we decide: exit of - * _what_ ? */ +#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. + */ +static volatile int sigaction_nodefer_works = -1; + +static void +sigaction_nodefer_test_handler(int signal, siginfo_t *info, void *void_context) +{ + sigset_t empty, current; + int i; + sigemptyset(&empty); + sigprocmask(SIG_BLOCK, &empty, ¤t); + for(i = 1; i < NSIG; i++) + if (sigismember(¤t, i) != ((i == SIGABRT) ? 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; +} -/* SBCL comment: The "undoably" aspect is because we also arrange with - * atexit() for the handler to be restored to its old value. This is - * for tidiness: it shouldn't matter much ordinarily, but it does - * remove a window where e.g. memory fault signals (SIGSEGV or SIGBUS, - * which in ordinary operation of SBCL are sent to the generational - * garbage collector, then possibly onward to Lisp code) or SIGINT - * (which is ordinarily passed to Lisp code) could otherwise be - * handled bizarrely/brokenly because the Lisp code would try to deal - * with them using machinery (like stream output buffers) which has - * already been dismantled. */ +static void +see_if_sigaction_nodefer_works() +{ + struct sigaction sa, old_sa; -/* I'm not sure (a) whether this is a real concern, (b) how it helps - anyway */ + sa.sa_flags = SA_SIGINFO | SA_NODEFER; + sa.sa_sigaction = sigaction_nodefer_test_handler; + sigemptyset(&sa.sa_mask); + sigaddset(&sa.sa_mask, SIGABRT); + sigaction(SIGUSR1, &sa, &old_sa); + /* Make sure no signals are blocked. */ + { + sigset_t empty; + sigemptyset(&empty); + sigprocmask(SIG_SETMASK, &empty, 0); + } + kill(getpid(), SIGUSR1); + while (sigaction_nodefer_works == -1); + sigaction(SIGUSR1, &old_sa, NULL); +} -void -uninstall_low_level_interrupt_handlers_atexit(void) +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, - void handler(int, - siginfo_t*, - void*)) + void handler(int, + siginfo_t*, + void*)) { struct sigaction sa; - struct thread *th=arch_os_get_current_thread(); - struct interrupt_data *data= - th ? th->interrupt_data : global_interrupt_data; if (0 > signal || signal >= NSIG) { - lose("bad signal number %d", signal); + lose("bad signal number %d\n", signal); } - sa.sa_sigaction = handler; - sigemptyset(&sa.sa_mask); - sigaddset_blockable(&sa.sa_mask); - sa.sa_flags = SA_SIGINFO | SA_RESTART; + 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; + else if (!sigaction_nodefer_works && + !sigismember(&blockable_sigset, signal)) + sa.sa_sigaction = low_level_unblock_me_trampoline; + 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) sa.sa_flags|= SA_ONSTACK; + if((signal==SIG_MEMORY_FAULT) +#ifdef SIG_MEMORY_FAULT2 + || (signal==SIG_MEMORY_FAULT2) +#endif +#ifdef SIG_INTERRUPT_THREAD + || (signal==SIG_INTERRUPT_THREAD) +#endif + ) + sa.sa_flags |= SA_ONSTACK; #endif - - sigaction(signal, &sa, NULL); - data->interrupt_low_level_handlers[signal] = - (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler); + + 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; - struct thread *th=arch_os_get_current_thread(); - struct interrupt_data *data= - th ? th->interrupt_data : global_interrupt_data; FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal)); sigemptyset(&new); sigaddset(&new, signal); - sigprocmask(SIG_BLOCK, &new, &old); - - sigemptyset(&new); - sigaddset_blockable(&new); - - FSHOW((stderr, "/interrupt_low_level_handlers[signal]=%d\n", - interrupt_low_level_handlers[signal])); - if (data->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(&new, signal)) { - sa.sa_sigaction = maybe_now_maybe_later; - } else { - sa.sa_sigaction = interrupt_handle_now_handler; - } - - sigemptyset(&sa.sa_mask); - sigaddset_blockable(&sa.sa_mask); - sa.sa_flags = SA_SIGINFO | SA_RESTART; - sigaction(signal, &sa, NULL); + 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 = data->interrupt_handlers[signal]; - data->interrupt_handlers[signal].c = handler; + oldhandler = interrupt_handlers[signal]; + interrupt_handlers[signal].c = handler; - sigprocmask(SIG_SETMASK, &old, 0); + 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() { +#ifndef LISP_FEATURE_WIN32 int i; SHOW("entering interrupt_init()"); - global_interrupt_data=calloc(sizeof(struct interrupt_data), 1); + 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++) { - global_interrupt_data->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; + 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 }