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 volatile lispobj thread_start_lock;
  32 extern struct interrupt_data * global_interrupt_data;
  33 extern int linux_no_threads_p;
  34
  35 int
  36 initial_thread_trampoline(struct thread *th)
  37 {
  38     lispobj function;
  39 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  40     lispobj *args = NULL;
  41 #endif
  42
  43     function = th->unbound_marker;
  44     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  45     if(arch_os_thread_init(th)==0) return 1;
  46
  47     if(th->os_thread < 1) lose("th->os_thread not set up right");
  48     th->state=STATE_RUNNING;
  49 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  50     return call_into_lisp_first_time(function,args,0);
  51 #else
  52     return funcall0(function);
  53 #endif
  54 }
  55
  56 #ifdef LISP_FEATURE_SB_THREAD
  57 void mark_thread_dead(struct thread *th) {
  58     funcall1(SymbolFunction(HANDLE_THREAD_EXIT),alloc_number(th->os_thread));
  59     /* I hope it's safe for a thread to detach itself inside a
  60      * cancellation cleanup */
  61     pthread_detach(th->os_thread);
  62     th->state=STATE_DEAD;
  63     /* FIXME: if gc hits here it will rip the stack from under us */
  64 }
  65
  66 /* this is the first thing that runs in the child (which is why the
  67  * silly calling convention).  Basically it calls the user's requested
  68  * lisp function after doing arch_os_thread_init and whatever other
  69  * bookkeeping needs to be done
  70  */
  71 int
  72 new_thread_trampoline(struct thread *th)
  73 {
  74     lispobj function,ret;
  75     function = th->unbound_marker;
  76     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  77     pthread_cleanup_push((void (*) (void *))mark_thread_dead,th);
  78     if(arch_os_thread_init(th)==0) return 1;
  79
  80     /* wait here until our thread is linked into all_threads: see below */
  81     while(th->os_thread<1) sched_yield();
  82
  83     th->state=STATE_RUNNING;
  84     ret = funcall0(function);
  85     /* execute cleanup */
  86     pthread_cleanup_pop(1);
  87     return ret;
  88 }
  89 #endif /* LISP_FEATURE_SB_THREAD */
  90
  91 /* this is called from any other thread to create the new one, and
  92  * initialize all parts of it that can be initialized from another
  93  * thread
  94  */
  95
  96 struct thread * create_thread_struct(lispobj initial_function) {
  97     union per_thread_data *per_thread;
  98     struct thread *th=0;        /*  subdue gcc */
  99     void *spaces=0;
 100
 101     /* may as well allocate all the spaces at once: it saves us from
 102      * having to decide what to do if only some of the allocations
 103      * succeed */
 104     spaces=os_validate(0,
 105                        THREAD_CONTROL_STACK_SIZE+
 106                        BINDING_STACK_SIZE+
 107                        ALIEN_STACK_SIZE+
 108                        dynamic_values_bytes+
 109                        32*SIGSTKSZ);
 110     if(!spaces)
 111          return NULL;
 112     per_thread=(union per_thread_data *)
 113         (spaces+
 114          THREAD_CONTROL_STACK_SIZE+
 115          BINDING_STACK_SIZE+
 116          ALIEN_STACK_SIZE);
 117
 118     if(all_threads) {
 119         memcpy(per_thread,arch_os_get_current_thread(),
 120                dynamic_values_bytes);
 121     } else {
 122 #ifdef LISP_FEATURE_SB_THREAD
 123         int i;
 124         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
 125             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
 126         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
 127             SetSymbolValue
 128                 (FREE_TLS_INDEX,
 129                  make_fixnum(MAX_INTERRUPTS+
 130                              sizeof(struct thread)/sizeof(lispobj)),
 131                  0);
 132 #define STATIC_TLS_INIT(sym,field) \
 133   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 134   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 135
 136         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 137         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 138         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 139         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
 140         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 141 #ifdef LISP_FEATURE_X86
 142         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 143         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 144 #endif
 145 #undef STATIC_TLS_INIT
 146 #endif
 147     }
 148
 149     th=&per_thread->thread;
 150     th->control_stack_start = spaces;
 151     th->binding_stack_start=
 152         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 153     th->control_stack_end = th->binding_stack_start;
 154     th->alien_stack_start=
 155         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 156     th->binding_stack_pointer=th->binding_stack_start;
 157     th->this=th;
 158     th->os_thread=0;
 159     th->interrupt_fun=NIL;
 160     th->interrupt_fun_lock=0;
 161     th->state=STATE_STARTING;
 162 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 163     th->alien_stack_pointer=((void *)th->alien_stack_start
 164                              + ALIEN_STACK_SIZE-N_WORD_BYTES);
 165 #else
 166     th->alien_stack_pointer=((void *)th->alien_stack_start);
 167 #endif
 168 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 169     th->pseudo_atomic_interrupted=0;
 170     th->pseudo_atomic_atomic=0;
 171 #endif
 172 #ifdef LISP_FEATURE_GENCGC
 173     gc_set_region_empty(&th->alloc_region);
 174 #endif
 175
 176 #ifndef LISP_FEATURE_SB_THREAD
 177     /* the tls-points-into-struct-thread trick is only good for threaded
 178      * sbcl, because unithread sbcl doesn't have tls.  So, we copy the
 179      * appropriate values from struct thread here, and make sure that
 180      * we use the appropriate SymbolValue macros to access any of the
 181      * variable quantities from the C runtime.  It's not quite OAOOM,
 182      * it just feels like it */
 183     SetSymbolValue(BINDING_STACK_START,(lispobj)th->binding_stack_start,th);
 184     SetSymbolValue(CONTROL_STACK_START,(lispobj)th->control_stack_start,th);
 185     SetSymbolValue(CONTROL_STACK_END,(lispobj)th->control_stack_end,th);
 186 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 187     SetSymbolValue(BINDING_STACK_POINTER,(lispobj)th->binding_stack_pointer,th);
 188     SetSymbolValue(ALIEN_STACK,(lispobj)th->alien_stack_pointer,th);
 189     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,(lispobj)th->pseudo_atomic_atomic,th);
 190     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
 191 #else
 192     current_binding_stack_pointer=th->binding_stack_pointer;
 193     current_control_stack_pointer=th->control_stack_start;
 194 #endif
 195 #endif
 196     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
 197     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
 198     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
 199     bind_variable(INTERRUPT_PENDING, NIL,th);
 200     bind_variable(INTERRUPTS_ENABLED,T,th);
 201
 202     th->interrupt_data = (struct interrupt_data *)
 203         os_validate(0,(sizeof (struct interrupt_data)));
 204     if(all_threads)
 205         memcpy(th->interrupt_data,
 206                arch_os_get_current_thread()->interrupt_data,
 207                sizeof (struct interrupt_data));
 208     else
 209         memcpy(th->interrupt_data,global_interrupt_data,
 210                sizeof (struct interrupt_data));
 211
 212     th->unbound_marker=initial_function;
 213     return th;
 214 }
 215
 216 void link_thread(struct thread *th,os_thread_t kid_tid)
 217 {
 218     sigset_t newset,oldset;
 219     sigemptyset(&newset);
 220     sigaddset_blockable(&newset);
 221     thread_sigmask(SIG_BLOCK, &newset, &oldset);
 222
 223     get_spinlock(&all_threads_lock,kid_tid);
 224     if (all_threads) all_threads->prev=th;
 225     th->next=all_threads;
 226     th->prev=0;
 227     all_threads=th;
 228     /* note that th->os_thread is 0 at this time.  We rely on
 229      * all_threads_lock to ensure that we don't have >1 thread with
 230      * os_thread=0 on the list at once
 231      */
 232     protect_control_stack_guard_page(th->os_thread,1);
 233     /* child will not start until this is set */
 234     th->os_thread=kid_tid;
 235     release_spinlock(&all_threads_lock);
 236
 237     thread_sigmask(SIG_SETMASK,&oldset,0);
 238 }
 239
 240 void create_initial_thread(lispobj initial_function) {
 241     struct thread *th=create_thread_struct(initial_function);
 242     os_thread_t kid_tid=thread_self();
 243     if(th && kid_tid>0) {
 244         link_thread(th,kid_tid);
 245         initial_thread_trampoline(all_threads); /* no return */
 246     } else lose("can't create initial thread");
 247 }
 248
 249 #ifdef LISP_FEATURE_SB_THREAD
 250 os_thread_t create_thread(lispobj initial_function) {
 251     struct thread *th;
 252     os_thread_t kid_tid=0;
 253     pthread_attr_t attr;
 254
 255     if(linux_no_threads_p) return 0;
 256     th=create_thread_struct(initial_function);
 257     if(th==0) return 0;
 258 #ifdef QSHOW_SIGNALS
 259     SHOW("create_thread:waiting on lock");
 260 #endif
 261     get_spinlock(&thread_start_lock,arch_os_get_current_thread()->os_thread);
 262 #ifdef QSHOW_SIGNALS
 263     SHOW("create_thread:got lock");
 264 #endif
 265     /* The new thread inherits the restrictive signal mask set here,
 266      * and enables signals again when it is set up properly. */
 267     {
 268         sigset_t newset,oldset;
 269         sigemptyset(&newset);
 270         sigaddset_blockable(&newset);
 271         thread_sigmask(SIG_BLOCK, &newset, &oldset);
 272         if((pthread_attr_init(&attr)) ||
 273            (pthread_attr_setstack(&attr,th->control_stack_start,
 274                                   THREAD_CONTROL_STACK_SIZE-16)) ||
 275            (pthread_create
 276             (&kid_tid,&attr,(void *(*)(void *))new_thread_trampoline,th)))
 277             kid_tid=0;
 278         thread_sigmask(SIG_SETMASK,&oldset,0);
 279     }
 280     if(kid_tid>0) {
 281         link_thread(th,kid_tid);
 282         /* it's started and initialized, it's safe to gc */
 283         release_spinlock(&thread_start_lock);
 284 #ifdef QSHOW_SIGNALS
 285         SHOW("create_thread:released lock");
 286 #endif
 287         /* by now the kid might have already exited */
 288         return kid_tid;
 289     } else {
 290         release_spinlock(&thread_start_lock);
 291 #ifdef QSHOW_SIGNALS
 292         SHOW("create_thread:released lock(failure)");
 293 #endif
 294         os_invalidate((os_vm_address_t) th->control_stack_start,
 295                       ((sizeof (lispobj))
 296                        * (th->control_stack_end-th->control_stack_start)) +
 297                       BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 298                       32*SIGSTKSZ);
 299         return 0;
 300     }
 301 }
 302 #endif
 303
 304 struct thread *find_thread_by_os_thread(os_thread_t tid)
 305 {
 306     struct thread *th;
 307     for_each_thread(th)
 308         if(th->os_thread==tid) return th;
 309     return 0;
 310 }
 311
 312 #if defined LISP_FEATURE_SB_THREAD
 313 /* This is not needed unless #+SB-THREAD, as there's a trivial null
 314  * unithread definition. */
 315
 316 void reap_dead_threads()
 317 {
 318     struct thread *th,*next,*prev=0;
 319     th=all_threads;
 320     while(th) {
 321         next=th->next;
 322         if(th->state==STATE_DEAD) {
 323 #ifdef LISP_FEATURE_GENCGC
 324             gc_alloc_update_page_tables(0, &th->alloc_region);
 325 #endif
 326             get_spinlock(&all_threads_lock,th->os_thread);
 327             if(prev) prev->next=next;
 328             else all_threads=next;
 329             release_spinlock(&all_threads_lock);
 330             if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
 331             os_invalidate((os_vm_address_t) th->control_stack_start,
 332                           ((sizeof (lispobj))
 333                            * (th->control_stack_end-th->control_stack_start)) +
 334                           BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 335                           32*SIGSTKSZ);
 336         } else
 337             prev=th;
 338         th=next;
 339     }
 340 }
 341
 342 int interrupt_thread(os_thread_t tid, lispobj function)
 343 {
 344     struct thread *th;
 345     for_each_thread(th)
 346         if((th->os_thread==tid) && (th->state != STATE_DEAD)) {
 347             /* In clone_threads, if A and B both interrupt C at approximately
 348              * the same time, it does not matter: the second signal will be
 349              * masked until the handler has returned from the first one.
 350              * In pthreads though, we can't put the knowledge of what function
 351              * to call into the siginfo, so we have to store it in the
 352              * destination thread, and do it in such a way that A won't
 353              * clobber B's interrupt.  Hence this stupid linked list.
 354              *
 355              * This does depend on SIG_INTERRUPT_THREAD being queued
 356              * (as POSIX RT signals are): we need to keep
 357              * interrupt_fun data for exactly as many signals as are
 358              * going to be received by the destination thread.
 359              */
 360             struct cons *c;
 361             int kill_status;
 362             /* mask the signals in case this thread is being interrupted */
 363             sigset_t newset,oldset;
 364             sigemptyset(&newset);
 365             sigaddset_blockable(&newset);
 366             thread_sigmask(SIG_BLOCK, &newset, &oldset);
 367
 368             get_spinlock(&th->interrupt_fun_lock,
 369                          (int)arch_os_get_current_thread());
 370             kill_status=thread_kill(th->os_thread,SIG_INTERRUPT_THREAD);
 371             if(kill_status==0) {
 372                 c=alloc_cons(function,th->interrupt_fun);
 373                 th->interrupt_fun=c;
 374             }
 375             release_spinlock(&th->interrupt_fun_lock);
 376             thread_sigmask(SIG_SETMASK,&oldset,0);
 377             return (kill_status ? -1 : 0);
 378         }
 379     errno=EPERM; return -1;
 380 }
 381
 382 /* stopping the world is a two-stage process.  From this thread we signal
 383  * all the others with SIG_STOP_FOR_GC.  The handler for this signal does
 384  * the usual pseudo-atomic checks (we don't want to stop a thread while
 385  * it's in the middle of allocation) then waits for another SIG_STOP_FOR_GC.
 386  */
 387
 388 void gc_stop_the_world()
 389 {
 390     struct thread *p,*th=arch_os_get_current_thread();
 391 #ifdef QSHOW_SIGNALS
 392     SHOW("gc_stop_the_world:begin");
 393 #endif
 394     /* keep threads from starting while the world is stopped. */
 395     get_spinlock(&thread_start_lock,th->os_thread);
 396 #ifdef QSHOW_SIGNALS
 397     SHOW("gc_stop_the_world:locked");
 398 #endif
 399     /* stop all other threads by sending them SIG_STOP_FOR_GC */
 400     for(p=all_threads; p; p=p->next) {
 401         while(p->state==STATE_STARTING) sched_yield();
 402         if((p!=th) && (p->os_thread!=0) && (p->state==STATE_RUNNING)) {
 403             p->state=STATE_STOPPING;
 404             if(thread_kill(p->os_thread,SIG_STOP_FOR_GC)==-1) {
 405                 /* FIXME: we can't kill the thread; assume because it died
 406                  * already */
 407                 p->state=STATE_DEAD;
 408             }
 409         }
 410     }
 411 #ifdef QSHOW_SIGNALS
 412     SHOW("gc_stop_the_world:signals sent");
 413 #endif
 414     /* wait for the running threads to stop */
 415     for(p=all_threads;p;) {
 416         if((p==th) || (p->os_thread==0) || (p->state==STATE_STARTING) ||
 417            (p->state==STATE_DEAD) || (p->state==STATE_STOPPED)) {
 418             p=p->next;
 419         }
 420     }
 421 #ifdef QSHOW_SIGNALS
 422     SHOW("gc_stop_the_world:end");
 423 #endif
 424 }
 425
 426 void gc_start_the_world()
 427 {
 428     struct thread *p,*th=arch_os_get_current_thread();
 429     /* if a resumed thread creates a new thread before we're done with
 430      * this loop, the new thread will get consed on the front of
 431      * all_threads, but it won't have been stopped so won't need
 432      * restarting; there can be threads just starting from before
 433      * gc_stop_the_world, though */
 434 #ifdef QSHOW_SIGNALS
 435     SHOW("gc_start_the_world:begin");
 436 #endif
 437     for(p=all_threads;p;p=p->next) {
 438         if((p!=th) && (p->os_thread!=0) && (p->state!=STATE_STARTING) &&
 439            (p->state!=STATE_DEAD)) {
 440             if(p->state!=STATE_STOPPED) {
 441                 lose("gc_start_the_world: wrong thread state is %ld\n",
 442                      fixnum_value(p->state));
 443             }
 444             thread_kill(p->os_thread,SIG_STOP_FOR_GC);
 445         }
 446     }
 447     /* we must wait for all threads to leave stopped state else we
 448      * risk signal accumulation and lose any meaning of
 449      * thread->state */
 450     for(p=all_threads;p;) {
 451         gc_assert(p->state!=STATE_STOPPING);
 452         if((p==th) || (p->os_thread==0) || (p->state!=STATE_STOPPED)) {
 453             p=p->next;
 454         }
 455     }
 456     release_spinlock(&thread_start_lock);
 457 #ifdef QSHOW_SIGNALS
 458     SHOW("gc_start_the_world:end");
 459 #endif
 460 }
 461 #endif