src/runtime/interrupt.h

   1 /*
   2  * This software is part of the SBCL system. See the README file for
   3  * more information.
   4  *
   5  * This software is derived from the CMU CL system, which was
   6  * written at Carnegie Mellon University and released into the
   7  * public domain. The software is in the public domain and is
   8  * provided with absolutely no warranty. See the COPYING and CREDITS
   9  * files for more information.
  10  */
  11
  12 #if !defined(_INCLUDE_INTERRUPT_H_)
  13 #define _INCLUDE_INTERRUPT_H_
  14
  15 #include <signal.h>
  16 #include <string.h>
  17
  18 /*
  19  * This is a workaround for some slightly silly Linux/GNU Libc
  20  * behaviour: glibc defines sigset_t to support 1024 signals, which is
  21  * more than the kernel.  This is usually not a problem, but becomes
  22  * one when we want to save a signal mask from a ucontext, and restore
  23  * it later into another ucontext: the ucontext is allocated on the
  24  * stack by the kernel, so copying a libc-sized sigset_t into it will
  25  * overflow and cause other data on the stack to be corrupted */
  26 /* FIXME: do not rely on NSIG being a multiple of 8 */
  27 #define REAL_SIGSET_SIZE_BYTES ((NSIG/8))
  28
  29 static inline void
  30 sigcopyset(sigset_t *new, sigset_t *old)
  31 {
  32     memcpy(new, old, REAL_SIGSET_SIZE_BYTES);
  33 }
  34
  35 extern void get_current_sigmask(sigset_t *sigset);
  36
  37 /* Set all deferrable signals into *s. */
  38 extern void sigaddset_deferrable(sigset_t *s);
  39 /* Set all blockable signals into *s. */
  40 extern void sigaddset_blockable(sigset_t *s);
  41 /* Set all gc signals into *s. */
  42 extern void sigaddset_gc(sigset_t *s);
  43
  44 extern sigset_t deferrable_sigset;
  45 extern sigset_t blockable_sigset;
  46 extern sigset_t gc_sigset;
  47
  48 extern boolean deferrables_blocked_p(sigset_t *sigset);
  49 extern boolean blockables_blocked_p(sigset_t *sigset);
  50 extern boolean gc_signals_blocked_p(sigset_t *sigset);
  51
  52 extern void check_deferrables_blocked_or_lose(sigset_t *sigset);
  53 extern void check_blockables_blocked_or_lose(sigset_t *sigset);
  54 extern void check_gc_signals_blocked_or_lose(sigset_t *sigset);
  55
  56 extern void check_deferrables_unblocked_or_lose(sigset_t *sigset);
  57 extern void check_blockables_unblocked_or_lose(sigset_t *sigset);
  58 extern void check_gc_signals_unblocked_or_lose(sigset_t *sigset);
  59
  60 extern void block_deferrable_signals(sigset_t *where, sigset_t *old);
  61 extern void block_blockable_signals(sigset_t *where, sigset_t *old);
  62 extern void block_gc_signals(sigset_t *where, sigset_t *old);
  63
  64 extern void unblock_deferrable_signals(sigset_t *where, sigset_t *old);
  65 extern void unblock_blockable_signals(sigset_t *where, sigset_t *old);
  66 extern void unblock_gc_signals(sigset_t *where, sigset_t *old);
  67
  68 extern void maybe_save_gc_mask_and_block_deferrables(sigset_t *sigset);
  69
  70 /* maximum signal nesting depth
  71  *
  72  * FIXME: In CMUCL this was 4096, and it was first scaled down to 256
  73  * and then 32, until finally Stumpwm broke: it is possible to receive
  74  * interrupts in sufficiently quick succession that handler nesting
  75  * can become preposterous. Scaling this back up to 1024 is a bandaid:
  76  * for a real fix we should consider the following things:
  77  *
  78  *   We should almost certainly always use
  79  *   arrange_return_to_lisp_function, though it needs to be thought
  80  *   about arguments, and it needs to be able to pass a frobbable
  81  *   context to the callee...
  82  *
  83  *   There are cases when nesting handlers is exactly what we want:
  84  *   eg. SIGINT.
  85  *
  86  *   There are cases when we probably want to drop duplicate signals
  87  *   on the floor if they arrive before the previous one has been handled.
  88  *   Eg. SIGPROF.
  89  *
  90  *   There are cases when we probably want to handle duplicate signals
  91  *   after the previous handler has returned, not before. Eg. SIGALARM.
  92  *
  93  * -- NS 2007-01-29
  94  */
  95 #define MAX_INTERRUPTS 1024
  96
  97 union interrupt_handler {
  98     lispobj lisp;
  99     void (*c)(int, siginfo_t*, os_context_t*);
 100 };
 101
 102 extern union interrupt_handler interrupt_handlers[NSIG];
 103
 104 struct interrupt_data {
 105     /* signal information for pending signal.  pending_signal=0 when there
 106      * is no pending signal. */
 107     void (*pending_handler) (int, siginfo_t*, os_context_t*) ;
 108     int pending_signal;
 109     siginfo_t pending_info;
 110     sigset_t pending_mask;
 111     /* Was pending mask saved for gc request? True if GC_PENDING or
 112      * SIG_STOP_FOR_GC happened in a pseudo atomic with GC_INHIBIT NIL
 113      * and with no pending handler. Both deferrable interrupt handlers
 114      * and gc are careful not to clobber each other's pending_mask. */
 115     boolean gc_blocked_deferrables;
 116 #ifdef LISP_FEATURE_PPC
 117     /* On PPC when consing wants to turn to alloc(), it does so via a
 118      * trap. When alloc() wants to save the sigmask it consults
 119      * allocation_trap_context. It does not look up the most recent
 120      * context, because alloc() can be called from other places
 121      * too. */
 122     os_context_t *allocation_trap_context;
 123 #endif
 124 };
 125
 126 extern boolean interrupt_handler_pending_p(void);
 127 extern void interrupt_init(void);
 128 extern void fake_foreign_function_call(os_context_t* context);
 129 extern void undo_fake_foreign_function_call(os_context_t* context);
 130 extern void arrange_return_to_lisp_function(os_context_t *, lispobj);
 131 extern void interrupt_handle_now(int, siginfo_t*, os_context_t*);
 132 extern void interrupt_handle_pending(os_context_t*);
 133 extern void interrupt_internal_error(os_context_t*, boolean continuable);
 134 extern boolean handle_guard_page_triggered(os_context_t *,os_vm_address_t);
 135 extern boolean maybe_defer_handler(void *handler, struct interrupt_data *data,
 136                                    int signal, siginfo_t *info,
 137                                    os_context_t *context);
 138 #if defined LISP_FEATURE_GENCGC
 139 /* assembly language stub that executes trap_PendingInterrupt */
 140 extern void do_pending_interrupt(void);
 141 #endif
 142
 143 #ifdef LISP_FEATURE_SB_THREAD
 144 extern void sig_stop_for_gc_handler(int, siginfo_t*, os_context_t*);
 145 #endif
 146 typedef void (*interrupt_handler_t)(int, siginfo_t *, os_context_t *);
 147 extern void undoably_install_low_level_interrupt_handler (
 148                         int signal,
 149                         interrupt_handler_t handler);
 150 extern unsigned long install_handler(int signal,
 151                                      interrupt_handler_t handler);
 152
 153 extern union interrupt_handler interrupt_handlers[NSIG];
 154
 155 /* The void* casting here avoids having to mess with the various types
 156  * of function argument lists possible for signal handlers:
 157  * SA_SIGACTION handlers have one signature, and the default old-style
 158  * signal(..) handlers have another, and attempting to represent them
 159  * "cleanly" with union types is in fact a mess. */
 160 #define ARE_SAME_HANDLER(x, y) ((void*)(x) == (void*)(y))
 161
 162 extern void handle_trap(os_context_t *context, int trap);
 163
 164 #ifndef LISP_FEATURE_WIN32
 165 extern void lisp_memory_fault_error(os_context_t *context,
 166                                     os_vm_address_t addr);
 167 #endif
 168
 169 #include "thread.h"
 170
 171 extern void lower_thread_control_stack_guard_page(struct thread *th);
 172 extern void reset_thread_control_stack_guard_page(struct thread *th);
 173
 174 #endif