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 "thread.h"
  15 #include "arch.h"
  16 #include "target-arch-os.h"
  17 #include "os.h"
  18 #include "globals.h"
  19 #include "dynbind.h"
  20 #include "genesis/cons.h"
  21 #include "genesis/fdefn.h"
  22 #include "interr.h"             /* for lose() */
  23 #include "gc-internal.h"
  24
  25 #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */
  26
  27 int dynamic_values_bytes=4096*sizeof(lispobj);  /* same for all threads */
  28 struct thread *all_threads;
  29 volatile lispobj all_threads_lock;
  30 volatile lispobj thread_start_lock;
  31 extern struct interrupt_data * global_interrupt_data;
  32 extern int linux_no_threads_p;
  33
  34 int
  35 initial_thread_trampoline(struct thread *th)
  36 {
  37     lispobj function;
  38 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  39     lispobj *args = NULL;
  40 #endif
  41
  42     function = th->unbound_marker;
  43     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  44     if(arch_os_thread_init(th)==0) return 1;
  45
  46     if(th->pid < 1) lose("th->pid not set up right");
  47     th->state=STATE_RUNNING;
  48 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  49     return call_into_lisp_first_time(function,args,0);
  50 #else
  51     return funcall0(function);
  52 #endif
  53 }
  54
  55 /* this is the first thing that clone() runs in the child (which is
  56  * why the silly calling convention).  Basically it calls the user's
  57  * requested lisp function after doing arch_os_thread_init and
  58  * whatever other bookkeeping needs to be done
  59  */
  60
  61 #ifdef LISP_FEATURE_SB_THREAD
  62 int
  63 new_thread_trampoline(struct thread *th)
  64 {
  65     lispobj function;
  66     function = th->unbound_marker;
  67     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  68     if(arch_os_thread_init(th)==0) return 1;
  69
  70     /* wait here until our thread is linked into all_threads: see below */
  71     while(th->pid<1) sched_yield();
  72
  73     th->state=STATE_RUNNING;
  74     return funcall0(function);
  75 }
  76 #endif /* LISP_FEATURE_SB_THREAD */
  77
  78 /* this is called from any other thread to create the new one, and
  79  * initialize all parts of it that can be initialized from another
  80  * thread
  81  */
  82
  83 struct thread * create_thread_struct(lispobj initial_function) {
  84     union per_thread_data *per_thread;
  85     struct thread *th=0;        /*  subdue gcc */
  86     void *spaces=0;
  87
  88     /* may as well allocate all the spaces at once: it saves us from
  89      * having to decide what to do if only some of the allocations
  90      * succeed */
  91     spaces=os_validate(0,
  92                        THREAD_CONTROL_STACK_SIZE+
  93                        BINDING_STACK_SIZE+
  94                        ALIEN_STACK_SIZE+
  95                        dynamic_values_bytes+
  96                        32*SIGSTKSZ);
  97     if(!spaces)
  98          return NULL;
  99     per_thread=(union per_thread_data *)
 100         (spaces+
 101          THREAD_CONTROL_STACK_SIZE+
 102          BINDING_STACK_SIZE+
 103          ALIEN_STACK_SIZE);
 104
 105     if(all_threads) {
 106         memcpy(per_thread,arch_os_get_current_thread(),
 107                dynamic_values_bytes);
 108     } else {
 109 #ifdef LISP_FEATURE_SB_THREAD
 110         int i;
 111         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
 112             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
 113         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
 114             SetSymbolValue
 115                 (FREE_TLS_INDEX,
 116                  make_fixnum(MAX_INTERRUPTS+
 117                              sizeof(struct thread)/sizeof(lispobj)),
 118                  0);
 119 #define STATIC_TLS_INIT(sym,field) \
 120   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 121   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 122
 123         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 124         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 125         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 126         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
 127         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 128 #ifdef LISP_FEATURE_X86
 129         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 130         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 131 #endif
 132 #undef STATIC_TLS_INIT
 133 #endif
 134     }
 135
 136     th=&per_thread->thread;
 137     th->control_stack_start = spaces;
 138     th->binding_stack_start=
 139         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 140     th->control_stack_end = th->binding_stack_start;
 141     th->alien_stack_start=
 142         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 143     th->binding_stack_pointer=th->binding_stack_start;
 144     th->this=th;
 145     th->pid=0;
 146     th->state=STATE_STARTING;
 147 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 148     th->alien_stack_pointer=((void *)th->alien_stack_start
 149                              + ALIEN_STACK_SIZE-N_WORD_BYTES);
 150 #else
 151     th->alien_stack_pointer=((void *)th->alien_stack_start);
 152 #endif
 153 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 154     th->pseudo_atomic_interrupted=0;
 155     th->pseudo_atomic_atomic=0;
 156 #endif
 157 #ifdef LISP_FEATURE_GENCGC
 158     gc_set_region_empty(&th->alloc_region);
 159 #endif
 160
 161 #ifndef LISP_FEATURE_SB_THREAD
 162     /* the tls-points-into-struct-thread trick is only good for threaded
 163      * sbcl, because unithread sbcl doesn't have tls.  So, we copy the
 164      * appropriate values from struct thread here, and make sure that
 165      * we use the appropriate SymbolValue macros to access any of the
 166      * variable quantities from the C runtime.  It's not quite OAOOM,
 167      * it just feels like it */
 168     SetSymbolValue(BINDING_STACK_START,(lispobj)th->binding_stack_start,th);
 169     SetSymbolValue(CONTROL_STACK_START,(lispobj)th->control_stack_start,th);
 170     SetSymbolValue(CONTROL_STACK_END,(lispobj)th->control_stack_end,th);
 171 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 172     SetSymbolValue(BINDING_STACK_POINTER,(lispobj)th->binding_stack_pointer,th);
 173     SetSymbolValue(ALIEN_STACK,(lispobj)th->alien_stack_pointer,th);
 174     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,(lispobj)th->pseudo_atomic_atomic,th);
 175     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
 176 #else
 177     current_binding_stack_pointer=th->binding_stack_pointer;
 178     current_control_stack_pointer=th->control_stack_start;
 179 #endif
 180 #endif
 181     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
 182     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
 183     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
 184     bind_variable(INTERRUPT_PENDING, NIL,th);
 185     bind_variable(INTERRUPTS_ENABLED,T,th);
 186
 187     th->interrupt_data =
 188         os_validate(0,(sizeof (struct interrupt_data)));
 189     if(all_threads)
 190         memcpy(th->interrupt_data,
 191                arch_os_get_current_thread()->interrupt_data,
 192                sizeof (struct interrupt_data));
 193     else
 194         memcpy(th->interrupt_data,global_interrupt_data,
 195                sizeof (struct interrupt_data));
 196
 197     th->unbound_marker=initial_function;
 198     return th;
 199 }
 200
 201 void link_thread(struct thread *th,pid_t kid_pid)
 202 {
 203     sigset_t newset,oldset;
 204     sigemptyset(&newset);
 205     sigaddset_blockable(&newset);
 206     sigprocmask(SIG_BLOCK, &newset, &oldset);
 207
 208     get_spinlock(&all_threads_lock,kid_pid);
 209     th->next=all_threads;
 210     all_threads=th;
 211     /* note that th->pid is 0 at this time.  We rely on all_threads_lock
 212      * to ensure that we don't have >1 thread with pid=0 on the list at once
 213      */
 214     protect_control_stack_guard_page(th->pid,1);
 215     th->pid=kid_pid;            /* child will not start until this is set */
 216     release_spinlock(&all_threads_lock);
 217
 218     sigprocmask(SIG_SETMASK,&oldset,0);
 219 }
 220
 221 void create_initial_thread(lispobj initial_function) {
 222     struct thread *th=create_thread_struct(initial_function);
 223     pid_t kid_pid=getpid();
 224     if(th && kid_pid>0) {
 225         link_thread(th,kid_pid);
 226         initial_thread_trampoline(all_threads); /* no return */
 227     } else lose("can't create initial thread");
 228 }
 229
 230 #ifdef LISP_FEATURE_SB_THREAD
 231 pid_t create_thread(lispobj initial_function) {
 232     struct thread *th;
 233     pid_t kid_pid=0;
 234
 235     if(linux_no_threads_p) return 0;
 236     th=create_thread_struct(initial_function);
 237     if(th==0) return 0;
 238 #ifdef QSHOW_SIGNALS
 239     SHOW("create_thread:waiting on lock");
 240 #endif
 241     get_spinlock(&thread_start_lock,arch_os_get_current_thread()->pid);
 242 #ifdef QSHOW_SIGNALS
 243     SHOW("create_thread:got lock");
 244 #endif
 245     kid_pid=clone(new_thread_trampoline,
 246                   (((void*)th->control_stack_start)+
 247                    THREAD_CONTROL_STACK_SIZE-16),
 248                   CLONE_FILES|SIG_THREAD_EXIT|CLONE_VM,th);
 249
 250     if(kid_pid>0) {
 251         link_thread(th,kid_pid);
 252         /* wait here until our thread is started: see new_thread_trampoline */
 253         while(th->state==STATE_STARTING) sched_yield();
 254         /* it's started and initialized, it's safe to gc */
 255         release_spinlock(&thread_start_lock);
 256 #ifdef QSHOW_SIGNALS
 257         SHOW("create_thread:released lock");
 258 #endif
 259         return th->pid;
 260     } else {
 261         release_spinlock(&thread_start_lock);
 262 #ifdef QSHOW_SIGNALS
 263         SHOW("create_thread:released lock(failure)");
 264 #endif
 265         os_invalidate((os_vm_address_t) th->control_stack_start,
 266                       ((sizeof (lispobj))
 267                        * (th->control_stack_end-th->control_stack_start)) +
 268                       BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 269                       32*SIGSTKSZ);
 270         return 0;
 271     }
 272 }
 273 #endif
 274
 275 struct thread *find_thread_by_pid(pid_t pid)
 276 {
 277     struct thread *th;
 278     for_each_thread(th)
 279         if(th->pid==pid) return th;
 280     return 0;
 281 }
 282
 283 #if defined LISP_FEATURE_SB_THREAD
 284 /* This is not needed unless #+SB-THREAD, as there's a trivial null
 285  * unithread definition. */
 286
 287 void mark_dead_threads()
 288 {
 289     pid_t kid;
 290     int status;
 291     while(1) {
 292         kid=waitpid(-1,&status,__WALL|WNOHANG);
 293         if(kid<=0) break;
 294         if(WIFEXITED(status) || WIFSIGNALED(status)) {
 295             struct thread *th=find_thread_by_pid(kid);
 296             if(th) th->state=STATE_DEAD;
 297         }
 298     }
 299 }
 300
 301 void reap_dead_threads()
 302 {
 303     struct thread *th,*next,*prev=0;
 304     th=all_threads;
 305     while(th) {
 306         next=th->next;
 307         if(th->state==STATE_DEAD) {
 308             funcall1(SymbolFunction(HANDLE_THREAD_EXIT),make_fixnum(th->pid));
 309 #ifdef LISP_FEATURE_GENCGC
 310             gc_alloc_update_page_tables(0, &th->alloc_region);
 311 #endif
 312             get_spinlock(&all_threads_lock,th->pid);
 313             if(prev) prev->next=next;
 314             else all_threads=next;
 315             release_spinlock(&all_threads_lock);
 316             if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
 317             os_invalidate((os_vm_address_t) th->control_stack_start,
 318                           ((sizeof (lispobj))
 319                            * (th->control_stack_end-th->control_stack_start)) +
 320                           BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 321                           32*SIGSTKSZ);
 322         } else
 323             prev=th;
 324         th=next;
 325     }
 326 }
 327
 328 int interrupt_thread(pid_t pid, lispobj function)
 329 {
 330     union sigval sigval;
 331     struct thread *th;
 332     sigval.sival_int=function;
 333     for_each_thread(th)
 334         if((th->pid==pid) && (th->state != STATE_DEAD))
 335             return sigqueue(pid, SIG_INTERRUPT_THREAD, sigval);
 336     errno=EPERM; return -1;
 337 }
 338
 339 int signal_thread_to_dequeue (pid_t pid)
 340 {
 341     return kill (pid, SIG_DEQUEUE);
 342 }
 343
 344
 345 /* stopping the world is a two-stage process.  From this thread we signal
 346  * all the others with SIG_STOP_FOR_GC.  The handler for this signal does
 347  * the usual pseudo-atomic checks (we don't want to stop a thread while
 348  * it's in the middle of allocation) then waits for another SIG_STOP_FOR_GC.
 349  */
 350
 351 void gc_stop_the_world()
 352 {
 353 #ifdef QSHOW_SIGNALS
 354     SHOW("gc_stop_the_world:begin");
 355 #endif
 356     struct thread *p,*th=arch_os_get_current_thread();
 357     /* keep threads from starting while the world is stopped. */
 358     get_spinlock(&thread_start_lock,th->pid);
 359 #ifdef QSHOW_SIGNALS
 360     SHOW("gc_stop_the_world:locked");
 361 #endif
 362     /* stop all other threads by sending them SIG_STOP_FOR_GC */
 363     for(p=all_threads; p; p=p->next) {
 364         if((p!=th) && (p->pid!=0) && (p->state==STATE_RUNNING)) {
 365             p->state=STATE_STOPPING;
 366             if(kill(p->pid,SIG_STOP_FOR_GC)==-1) {
 367                 /* we can't kill the process; assume because it
 368                  * died already (and its parent is dead so never
 369                  * saw the SIGCHLD) */
 370                 p->state=STATE_DEAD;
 371             }
 372         }
 373     }
 374 #ifdef QSHOW_SIGNALS
 375     SHOW("gc_stop_the_world:signals sent");
 376 #endif
 377     /* wait for the running threads to stop */
 378     for(p=all_threads;p;) {
 379         if((p==th) || (p->pid==0) || (p->state==STATE_STARTING) ||
 380            (p->state==STATE_DEAD) || (p->state==STATE_STOPPED)) {
 381             p=p->next;
 382         }
 383     }
 384 #ifdef QSHOW_SIGNALS
 385     SHOW("gc_stop_the_world:end");
 386 #endif
 387 }
 388
 389 void gc_start_the_world()
 390 {
 391     struct thread *p,*th=arch_os_get_current_thread();
 392     /* if a resumed thread creates a new thread before we're done with
 393      * this loop, the new thread will get consed on the front of
 394      * all_threads, but it won't have been stopped so won't need
 395      * restarting; there can be threads just starting from before
 396      * gc_stop_the_world, though */
 397 #ifdef QSHOW_SIGNALS
 398     SHOW("gc_start_the_world:begin");
 399 #endif
 400     for(p=all_threads;p;p=p->next) {
 401         if((p!=th) && (p->pid!=0) && (p->state!=STATE_STARTING) &&
 402            (p->state!=STATE_DEAD)) {
 403             if(p->state!=STATE_STOPPED) {
 404                 lose("gc_start_the_world: wrong thread state is %ld\n",
 405                      fixnum_value(p->state));
 406             }
 407             kill(p->pid,SIG_STOP_FOR_GC);
 408         }
 409     }
 410     /* we must wait for all threads to leave stopped state else we
 411      * risk signal accumulation and lose any meaning of
 412      * thread->state */
 413     for(p=all_threads;p;) {
 414         gc_assert(p->state!=STATE_STOPPING);
 415         if((p==th) || (p->pid==0) || (p->state!=STATE_STOPPED)) {
 416             p=p->next;
 417         }
 418     }
 419     release_spinlock(&thread_start_lock);
 420 #ifdef QSHOW_SIGNALS
 421     SHOW("gc_start_the_world:end");
 422 #endif
 423 }
 424 #endif