src/runtime/thread.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <sched.h>
   5 #include <signal.h>
   6 #include <stddef.h>
   7 #include <errno.h>
   8 #include <sys/types.h>
   9 #include <sys/wait.h>
  10
  11 #include "sbcl.h"
  12 #include "runtime.h"
  13 #include "validate.h"           /* for CONTROL_STACK_SIZE etc */
  14 #include "alloc.h"
  15 #include "thread.h"
  16 #include "arch.h"
  17 #include "target-arch-os.h"
  18 #include "os.h"
  19 #include "globals.h"
  20 #include "dynbind.h"
  21 #include "genesis/cons.h"
  22 #include "genesis/fdefn.h"
  23 #include "interr.h"             /* for lose() */
  24 #include "gc-internal.h"
  25
  26 #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */
  27
  28 int dynamic_values_bytes=4096*sizeof(lispobj);  /* same for all threads */
  29 struct thread *all_threads;
  30 volatile lispobj all_threads_lock;
  31 extern struct interrupt_data * global_interrupt_data;
  32 extern int linux_no_threads_p;
  33
  34 #ifdef LISP_FEATURE_SB_THREAD
  35 /* When trying to get all_threads_lock one should make sure that
  36  * sig_stop_for_gc is not blocked. Else there would be a possible
  37  * deadlock: gc locks it, other thread blocks signals, gc sends stop
  38  * request to other thread and waits, other thread blocks on lock. */
  39 void check_sig_stop_for_gc_can_arrive_or_lose()
  40 {
  41     /* Get the current sigmask, by blocking the empty set. */
  42     sigset_t empty,current;
  43     sigemptyset(&empty);
  44     thread_sigmask(SIG_BLOCK, &empty, &current);
  45     if (sigismember(&current,SIG_STOP_FOR_GC))
  46         lose("SIG_STOP_FOR_GC is blocked\n");
  47     if (SymbolValue(INTERRUPTS_ENABLED,arch_os_get_current_thread()) == NIL)
  48         lose("interrupts disabled\n");
  49     if (arch_pseudo_atomic_atomic(NULL))
  50         lose("n pseudo atomic\n");
  51 }
  52
  53 #ifdef QSHOW_SIGNALS
  54 #define FSHOW_SIGNAL FSHOW
  55 #else
  56 #define FSHOW_SIGNAL(args)
  57 #endif
  58
  59 #define GET_ALL_THREADS_LOCK(name) \
  60     { \
  61         sigset_t _newset,_oldset; \
  62         sigemptyset(&_newset); \
  63         sigaddset_blockable(&_newset); \
  64         sigdelset(&_newset,SIG_STOP_FOR_GC); \
  65         thread_sigmask(SIG_BLOCK, &_newset, &_oldset); \
  66         check_sig_stop_for_gc_can_arrive_or_lose(); \
  67         FSHOW_SIGNAL((stderr,"/%s:waiting on lock=%ld, thread=%ld\n",name, \
  68                all_threads_lock,arch_os_get_current_thread()->os_thread)); \
  69         get_spinlock(&all_threads_lock,(long)arch_os_get_current_thread()); \
  70         FSHOW_SIGNAL((stderr,"/%s:got lock, thread=%ld\n", \
  71                name,arch_os_get_current_thread()->os_thread));
  72
  73 #define RELEASE_ALL_THREADS_LOCK(name) \
  74         FSHOW_SIGNAL((stderr,"/%s:released lock\n",name)); \
  75         release_spinlock(&all_threads_lock); \
  76         thread_sigmask(SIG_SETMASK,&_oldset,0); \
  77     }
  78 #endif
  79
  80
  81 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  82 extern lispobj call_into_lisp_first_time(lispobj fun, lispobj *args, int nargs);
  83 #endif
  84
  85 int
  86 initial_thread_trampoline(struct thread *th)
  87 {
  88     lispobj function;
  89 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  90     lispobj *args = NULL;
  91 #endif
  92     function = th->unbound_marker;
  93     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  94     if(arch_os_thread_init(th)==0) return 1;
  95
  96     if(th->os_thread < 1) lose("th->os_thread not set up right");
  97     th->state=STATE_RUNNING;
  98 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  99     return call_into_lisp_first_time(function,args,0);
 100 #else
 101     return funcall0(function);
 102 #endif
 103 }
 104
 105 #ifdef LISP_FEATURE_SB_THREAD
 106
 107 /* this is the first thing that runs in the child (which is why the
 108  * silly calling convention).  Basically it calls the user's requested
 109  * lisp function after doing arch_os_thread_init and whatever other
 110  * bookkeeping needs to be done
 111  */
 112 int
 113 new_thread_trampoline(struct thread *th)
 114 {
 115     lispobj function;
 116     function = th->unbound_marker;
 117     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
 118     if(arch_os_thread_init(th)==0) return 1;
 119
 120     /* wait here until our thread is linked into all_threads: see below */
 121     while(th->os_thread<1) sched_yield();
 122
 123     th->state=STATE_RUNNING;
 124     return funcall0(function);
 125 }
 126 #endif /* LISP_FEATURE_SB_THREAD */
 127
 128 /* this is called from any other thread to create the new one, and
 129  * initialize all parts of it that can be initialized from another
 130  * thread
 131  */
 132
 133 struct thread * create_thread_struct(lispobj initial_function) {
 134     union per_thread_data *per_thread;
 135     struct thread *th=0;        /*  subdue gcc */
 136     void *spaces=0;
 137
 138     /* may as well allocate all the spaces at once: it saves us from
 139      * having to decide what to do if only some of the allocations
 140      * succeed */
 141     spaces=os_validate(0,
 142                        THREAD_CONTROL_STACK_SIZE+
 143                        BINDING_STACK_SIZE+
 144                        ALIEN_STACK_SIZE+
 145                        dynamic_values_bytes+
 146                        32*SIGSTKSZ);
 147     if(!spaces)
 148          return NULL;
 149     per_thread=(union per_thread_data *)
 150         (spaces+
 151          THREAD_CONTROL_STACK_SIZE+
 152          BINDING_STACK_SIZE+
 153          ALIEN_STACK_SIZE);
 154
 155     if(all_threads) {
 156         memcpy(per_thread,arch_os_get_current_thread(),
 157                dynamic_values_bytes);
 158     } else {
 159 #ifdef LISP_FEATURE_SB_THREAD
 160         int i;
 161         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
 162             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
 163         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
 164             SetSymbolValue
 165                 (FREE_TLS_INDEX,
 166                  make_fixnum(MAX_INTERRUPTS+
 167                              sizeof(struct thread)/sizeof(lispobj)),
 168                  0);
 169 #define STATIC_TLS_INIT(sym,field) \
 170   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 171   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 172
 173         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 174         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 175         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 176         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
 177         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 178 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 179         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 180         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 181 #endif
 182 #undef STATIC_TLS_INIT
 183 #endif
 184     }
 185
 186     th=&per_thread->thread;
 187     th->control_stack_start = spaces;
 188     th->binding_stack_start=
 189         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 190     th->control_stack_end = th->binding_stack_start;
 191     th->alien_stack_start=
 192         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 193     th->binding_stack_pointer=th->binding_stack_start;
 194     th->this=th;
 195     th->os_thread=0;
 196     th->interrupt_fun=NIL;
 197     th->interrupt_fun_lock=0;
 198     th->state=STATE_STARTING;
 199 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 200     th->alien_stack_pointer=((void *)th->alien_stack_start
 201                              + ALIEN_STACK_SIZE-N_WORD_BYTES);
 202 #else
 203     th->alien_stack_pointer=((void *)th->alien_stack_start);
 204 #endif
 205 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 206     th->pseudo_atomic_interrupted=0;
 207     th->pseudo_atomic_atomic=0;
 208 #endif
 209 #ifdef LISP_FEATURE_GENCGC
 210     gc_set_region_empty(&th->alloc_region);
 211 #endif
 212
 213 #ifndef LISP_FEATURE_SB_THREAD
 214     /* the tls-points-into-struct-thread trick is only good for threaded
 215      * sbcl, because unithread sbcl doesn't have tls.  So, we copy the
 216      * appropriate values from struct thread here, and make sure that
 217      * we use the appropriate SymbolValue macros to access any of the
 218      * variable quantities from the C runtime.  It's not quite OAOOM,
 219      * it just feels like it */
 220     SetSymbolValue(BINDING_STACK_START,(lispobj)th->binding_stack_start,th);
 221     SetSymbolValue(CONTROL_STACK_START,(lispobj)th->control_stack_start,th);
 222     SetSymbolValue(CONTROL_STACK_END,(lispobj)th->control_stack_end,th);
 223 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 224     SetSymbolValue(BINDING_STACK_POINTER,(lispobj)th->binding_stack_pointer,th);
 225     SetSymbolValue(ALIEN_STACK,(lispobj)th->alien_stack_pointer,th);
 226     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,(lispobj)th->pseudo_atomic_atomic,th);
 227     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
 228 #else
 229     current_binding_stack_pointer=th->binding_stack_pointer;
 230     current_control_stack_pointer=th->control_stack_start;
 231 #endif
 232 #endif
 233     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
 234     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
 235     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
 236     bind_variable(INTERRUPT_PENDING, NIL,th);
 237     bind_variable(INTERRUPTS_ENABLED,T,th);
 238
 239     th->interrupt_data = (struct interrupt_data *)
 240         os_validate(0,(sizeof (struct interrupt_data)));
 241     if(all_threads)
 242         memcpy(th->interrupt_data,
 243                arch_os_get_current_thread()->interrupt_data,
 244                sizeof (struct interrupt_data));
 245     else
 246         memcpy(th->interrupt_data,global_interrupt_data,
 247                sizeof (struct interrupt_data));
 248
 249     th->unbound_marker=initial_function;
 250     return th;
 251 }
 252
 253 void link_thread(struct thread *th,os_thread_t kid_tid)
 254 {
 255     if (all_threads) all_threads->prev=th;
 256     th->next=all_threads;
 257     th->prev=0;
 258     all_threads=th;
 259     /* note that th->os_thread is 0 at this time.  We rely on
 260      * all_threads_lock to ensure that we don't have >1 thread with
 261      * os_thread=0 on the list at once
 262      */
 263     protect_control_stack_guard_page(th,1);
 264     /* child will not start until this is set */
 265     th->os_thread=kid_tid;
 266 }
 267
 268 void create_initial_thread(lispobj initial_function) {
 269     struct thread *th=create_thread_struct(initial_function);
 270     os_thread_t kid_tid=thread_self();
 271     if(th && kid_tid>0) {
 272         link_thread(th,kid_tid);
 273         initial_thread_trampoline(all_threads); /* no return */
 274     } else lose("can't create initial thread");
 275 }
 276
 277 #ifdef LISP_FEATURE_SB_THREAD
 278
 279 #ifndef __USE_XOPEN2K
 280 extern int pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
 281                                   size_t __stacksize);
 282 #endif
 283
 284 boolean create_os_thread(struct thread *th,os_thread_t *kid_tid)
 285 {
 286     /* The new thread inherits the restrictive signal mask set here,
 287      * and enables signals again when it is set up properly. */
 288     pthread_attr_t attr;
 289     sigset_t newset,oldset;
 290     boolean r=1;
 291     sigemptyset(&newset);
 292     sigaddset_blockable(&newset);
 293     thread_sigmask(SIG_BLOCK, &newset, &oldset);
 294
 295     if((pthread_attr_init(&attr)) ||
 296        (pthread_attr_setstack(&attr,th->control_stack_start,
 297                               THREAD_CONTROL_STACK_SIZE-16)) ||
 298        (pthread_create
 299         (kid_tid,&attr,(void *(*)(void *))new_thread_trampoline,th)))
 300         r=0;
 301     thread_sigmask(SIG_SETMASK,&oldset,0);
 302     return r;
 303 }
 304
 305 struct thread *create_thread(lispobj initial_function) {
 306     struct thread *th;
 307     os_thread_t kid_tid=0;
 308     boolean success;
 309
 310     if(linux_no_threads_p) return 0;
 311
 312     th=create_thread_struct(initial_function);
 313     if(th==0) return 0;
 314
 315     /* we must not be interrupted here after a successful
 316      * create_os_thread, because the kid will be waiting for its
 317      * thread struct to be linked */
 318     GET_ALL_THREADS_LOCK("create_thread")
 319
 320     success=create_os_thread(th,&kid_tid);
 321     if (success)
 322         link_thread(th,kid_tid);
 323     else
 324         os_invalidate((os_vm_address_t) th->control_stack_start,
 325                       ((sizeof (lispobj))
 326                        * (th->control_stack_end-th->control_stack_start)) +
 327                       BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 328                       32*SIGSTKSZ);
 329
 330     RELEASE_ALL_THREADS_LOCK("create_thread")
 331
 332     if (success)
 333         return th;
 334     else
 335         return 0;
 336 }
 337
 338 /* called from lisp from the thread object finalizer */
 339 void reap_dead_thread(struct thread *th)
 340 {
 341     if(th->state!=STATE_DEAD)
 342         lose("thread %p is not joinable, state=%d\n",th,th->state);
 343 #ifdef LISP_FEATURE_GENCGC
 344     {
 345         sigset_t newset,oldset;
 346         sigemptyset(&newset);
 347         sigaddset_blockable(&newset);
 348         thread_sigmask(SIG_BLOCK, &newset, &oldset);
 349         gc_alloc_update_page_tables(0, &th->alloc_region);
 350         release_spinlock(&all_threads_lock);
 351         thread_sigmask(SIG_SETMASK,&oldset,0);
 352     }
 353 #endif
 354     GET_ALL_THREADS_LOCK("reap_dead_thread")
 355     FSHOW((stderr,"/reap_dead_thread: reaping %ld\n",th->os_thread));
 356     if(th->prev)
 357         th->prev->next=th->next;
 358     else all_threads=th->next;
 359     if(th->next)
 360         th->next->prev=th->prev;
 361     RELEASE_ALL_THREADS_LOCK("reap_dead_thread")
 362     if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
 363     gc_assert(pthread_join(th->os_thread,NULL)==0);
 364     os_invalidate((os_vm_address_t) th->control_stack_start,
 365                   ((sizeof (lispobj))
 366                    * (th->control_stack_end-th->control_stack_start)) +
 367                   BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 368                   32*SIGSTKSZ);
 369 }
 370
 371 int interrupt_thread(struct thread *th, lispobj function)
 372 {
 373     /* A thread may also become dead after this test. */
 374     if ((th->state != STATE_DEAD)) {
 375         /* In clone_threads, if A and B both interrupt C at
 376          * approximately the same time, it does not matter: the
 377          * second signal will be masked until the handler has
 378          * returned from the first one.  In pthreads though, we
 379          * can't put the knowledge of what function to call into
 380          * the siginfo, so we have to store it in the destination
 381          * thread, and do it in such a way that A won't clobber
 382          * B's interrupt.  Hence this stupid linked list.
 383          *
 384          * This does depend on SIG_INTERRUPT_THREAD being queued
 385          * (as POSIX RT signals are): we need to keep
 386          * interrupt_fun data for exactly as many signals as are
 387          * going to be received by the destination thread.
 388          */
 389         lispobj c=alloc_cons(function,NIL);
 390         int kill_status;
 391         /* interrupt_thread_handler locks this spinlock with
 392          * interrupts blocked and it does so for the sake of
 393          * arrange_return_to_lisp_function, so we must also block
 394          * them. */
 395         sigset_t newset,oldset;
 396         sigemptyset(&newset);
 397         sigaddset_blockable(&newset);
 398         thread_sigmask(SIG_BLOCK, &newset, &oldset);
 399         get_spinlock(&th->interrupt_fun_lock,
 400                      (long)arch_os_get_current_thread());
 401         kill_status=thread_kill(th->os_thread,SIG_INTERRUPT_THREAD);
 402         if(kill_status==0) {
 403             ((struct cons *)native_pointer(c))->cdr=th->interrupt_fun;
 404             th->interrupt_fun=c;
 405         }
 406         release_spinlock(&th->interrupt_fun_lock);
 407         thread_sigmask(SIG_SETMASK,&oldset,0);
 408         return (kill_status ? -1 : 0);
 409     }
 410     errno=EPERM; return -1;
 411 }
 412
 413 /* stopping the world is a two-stage process.  From this thread we signal
 414  * all the others with SIG_STOP_FOR_GC.  The handler for this signal does
 415  * the usual pseudo-atomic checks (we don't want to stop a thread while
 416  * it's in the middle of allocation) then waits for another SIG_STOP_FOR_GC.
 417  */
 418
 419 /* To avoid deadlocks when gc stops the world all clients of each
 420  * mutex must enable or disable SIG_STOP_FOR_GC for the duration of
 421  * holding the lock, but they must agree on which. */
 422 void gc_stop_the_world()
 423 {
 424     struct thread *p,*th=arch_os_get_current_thread();
 425     FSHOW_SIGNAL((stderr,"/gc_stop_the_world:waiting on lock, thread=%ld\n",
 426                   th->os_thread));
 427     /* keep threads from starting while the world is stopped. */
 428     get_spinlock(&all_threads_lock,(long)th);
 429     FSHOW_SIGNAL((stderr,"/gc_stop_the_world:got lock, thread=%ld\n",
 430                   th->os_thread));
 431     /* stop all other threads by sending them SIG_STOP_FOR_GC */
 432     for(p=all_threads; p; p=p->next) {
 433         while(p->state==STATE_STARTING) sched_yield();
 434         if((p!=th) && (p->state==STATE_RUNNING)) {
 435             FSHOW_SIGNAL((stderr,"/gc_stop_the_world:sending sig_stop to %ld\n",
 436                           p->os_thread));
 437             if(thread_kill(p->os_thread,SIG_STOP_FOR_GC)==-1) {
 438                 /* we can't kill the thread; assume because it died
 439                  * since we last checked */
 440                 p->state=STATE_DEAD;
 441                 FSHOW_SIGNAL((stderr,"/gc_stop_the_world:assuming %ld dead\n",
 442                    p->os_thread));
 443             }
 444         }
 445     }
 446     FSHOW_SIGNAL((stderr,"/gc_stop_the_world:signals sent\n"));
 447     /* wait for the running threads to stop or finish */
 448     for(p=all_threads;p;) {
 449         gc_assert(p->os_thread!=0);
 450         gc_assert(p->state!=STATE_STARTING);
 451         if((p==th) || (p->state==STATE_SUSPENDED) ||
 452            (p->state==STATE_DEAD)) {
 453             p=p->next;
 454         }
 455     }
 456     FSHOW_SIGNAL((stderr,"/gc_stop_the_world:end\n"));
 457 }
 458
 459 void gc_start_the_world()
 460 {
 461     struct thread *p,*th=arch_os_get_current_thread();
 462     /* if a resumed thread creates a new thread before we're done with
 463      * this loop, the new thread will get consed on the front of
 464      * all_threads, but it won't have been stopped so won't need
 465      * restarting */
 466     FSHOW_SIGNAL((stderr,"/gc_start_the_world:begin\n"));
 467     for(p=all_threads;p;p=p->next) {
 468         gc_assert(p->os_thread!=0);
 469         if((p!=th) && (p->state!=STATE_DEAD)) {
 470             if(p->state!=STATE_SUSPENDED) {
 471                 lose("gc_start_the_world: wrong thread state is %ld\n",
 472                      fixnum_value(p->state));
 473             }
 474             thread_kill(p->os_thread,SIG_STOP_FOR_GC);
 475         }
 476     }
 477     /* we must wait for all threads to leave stopped state else we
 478      * risk signal accumulation and lose any meaning of
 479      * thread->state */
 480     for(p=all_threads;p;) {
 481         if((p==th) || (p->state!=STATE_SUSPENDED)) {
 482             p=p->next;
 483         }
 484     }
 485     release_spinlock(&all_threads_lock);
 486     FSHOW_SIGNAL((stderr,"/gc_start_the_world:end\n"));
 487 }
 488 #endif