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