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 "runtime.h"
  12 #include "sbcl.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 #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */
  23
  24 int dynamic_values_bytes=4096*sizeof(lispobj);  /* same for all threads */
  25 struct thread *all_threads;
  26 volatile lispobj all_threads_lock;
  27 extern struct interrupt_data * global_interrupt_data;
  28
  29 int
  30 initial_thread_trampoline(struct thread *th)
  31 {
  32     lispobj function;
  33     lispobj *args = NULL;
  34     function = th->unbound_marker;
  35     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  36     if(arch_os_thread_init(th)==0) return 1;
  37
  38     if(th->pid < 1) lose("th->pid not set up right");
  39     th->state=STATE_RUNNING;
  40 #if defined(LISP_FEATURE_X86)
  41     return call_into_lisp_first_time(function,args,0);
  42 #else
  43     return funcall0(function);
  44 #endif
  45 }
  46
  47 /* this is the first thing that clone() runs in the child (which is
  48  * why the silly calling convention).  Basically it calls the user's
  49  * requested lisp function after doing arch_os_thread_init and
  50  * whatever other bookkeeping needs to be done
  51  */
  52
  53 #ifdef LISP_FEATURE_SB_THREAD
  54 int
  55 new_thread_trampoline(struct thread *th)
  56 {
  57     lispobj function;
  58     function = th->unbound_marker;
  59     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  60     if(arch_os_thread_init(th)==0) return 1;
  61
  62     /* wait here until our thread is linked into all_threads: see below */
  63     while(th->pid<1) sched_yield();
  64
  65     th->state=STATE_RUNNING;
  66     return funcall0(function);
  67 }
  68 #endif /* LISP_FEATURE_SB_THREAD */
  69
  70 /* this is called from any other thread to create the new one, and
  71  * initialize all parts of it that can be initialized from another
  72  * thread
  73  */
  74
  75 struct thread * create_thread_struct(lispobj initial_function) {
  76     union per_thread_data *per_thread;
  77     struct thread *th=0;        /*  subdue gcc */
  78     void *spaces=0;
  79
  80     /* may as well allocate all the spaces at once: it saves us from
  81      * having to decide what to do if only some of the allocations
  82      * succeed */
  83     spaces=os_validate(0,
  84                        THREAD_CONTROL_STACK_SIZE+
  85                        BINDING_STACK_SIZE+
  86                        ALIEN_STACK_SIZE+
  87                        dynamic_values_bytes+
  88                        32*SIGSTKSZ
  89                        );
  90     if(!spaces) goto cleanup;
  91     per_thread=(union per_thread_data *)
  92         (spaces+
  93          THREAD_CONTROL_STACK_SIZE+
  94          BINDING_STACK_SIZE+
  95          ALIEN_STACK_SIZE);
  96
  97     th=&per_thread->thread;
  98     if(all_threads) {
  99         memcpy(per_thread,arch_os_get_current_thread(),
 100                dynamic_values_bytes);
 101     } else {
 102 #ifdef LISP_FEATURE_SB_THREAD
 103         int i;
 104         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
 105             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
 106         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
 107             SetSymbolValue
 108                 (FREE_TLS_INDEX,
 109                  make_fixnum(MAX_INTERRUPTS+
 110                              sizeof(struct thread)/sizeof(lispobj)),
 111                  0);
 112 #define STATIC_TLS_INIT(sym,field) \
 113   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 114   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 115
 116         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 117         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 118         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 119         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
 120         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 121 #ifdef LISP_FEATURE_X86
 122         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 123         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 124 #endif
 125 #undef STATIC_TLS_INIT
 126 #endif
 127     }
 128
 129     th->control_stack_start = spaces;
 130     th->binding_stack_start=
 131         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 132     th->control_stack_end = th->binding_stack_start;
 133     th->alien_stack_start=
 134         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 135     th->binding_stack_pointer=th->binding_stack_start;
 136     th->this=th;
 137     th->pid=0;
 138     th->state=STATE_STOPPED;
 139 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 140     th->alien_stack_pointer=((void *)th->alien_stack_start
 141                              + ALIEN_STACK_SIZE-4); /* naked 4.  FIXME */
 142 #else
 143     th->alien_stack_pointer=((void *)th->alien_stack_start);
 144 #endif
 145 #ifdef LISP_FEATURE_X86
 146     th->pseudo_atomic_interrupted=0;
 147     th->pseudo_atomic_atomic=0;
 148 #endif
 149 #ifdef LISP_FEATURE_GENCGC
 150     gc_set_region_empty(&th->alloc_region);
 151 #endif
 152
 153 #ifndef LISP_FEATURE_SB_THREAD
 154     /* the tls-points-into-struct-thread trick is only good for threaded
 155      * sbcl, because unithread sbcl doesn't have tls.  So, we copy the
 156      * appropriate values from struct thread here, and make sure that
 157      * we use the appropriate SymbolValue macros to access any of the
 158      * variable quantities from the C runtime.  It's not quite OAOOM,
 159      * it just feels like it */
 160     SetSymbolValue(BINDING_STACK_START,th->binding_stack_start,th);
 161     SetSymbolValue(CONTROL_STACK_START,th->control_stack_start,th);
 162     SetSymbolValue(CONTROL_STACK_END,th->control_stack_end,th);
 163 #ifdef LISP_FEATURE_X86
 164     SetSymbolValue(BINDING_STACK_POINTER,th->binding_stack_pointer,th);
 165     SetSymbolValue(ALIEN_STACK,th->alien_stack_pointer,th);
 166     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,th->pseudo_atomic_atomic,th);
 167     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
 168 #else
 169     current_binding_stack_pointer=th->binding_stack_pointer;
 170     current_control_stack_pointer=th->control_stack_start;
 171 #endif
 172 #endif
 173     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
 174     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
 175     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
 176     bind_variable(INTERRUPT_PENDING, NIL,th);
 177     bind_variable(INTERRUPTS_ENABLED,T,th);
 178
 179     th->interrupt_data=os_validate(0,(sizeof (struct interrupt_data)));
 180     if(all_threads)
 181         memcpy(th->interrupt_data,
 182                arch_os_get_current_thread()->interrupt_data,
 183                sizeof (struct interrupt_data));
 184     else
 185         memcpy(th->interrupt_data,global_interrupt_data,
 186                sizeof (struct interrupt_data));
 187
 188     th->unbound_marker=initial_function;
 189     return th;
 190  cleanup:
 191     /* if(th && th->tls_cookie>=0) os_free_tls_pointer(th); */
 192     if(spaces) os_invalidate(spaces,
 193                              THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+
 194                              ALIEN_STACK_SIZE+dynamic_values_bytes);
 195     return 0;
 196 }
 197
 198 void link_thread(struct thread *th,pid_t kid_pid)
 199 {
 200     sigset_t newset,oldset;
 201     sigemptyset(&newset);
 202     sigaddset_blockable(&newset);
 203     sigprocmask(SIG_BLOCK, &newset, &oldset);
 204
 205     get_spinlock(&all_threads_lock,kid_pid);
 206     th->next=all_threads;
 207     all_threads=th;
 208     /* note that th->pid is 0 at this time.  We rely on all_threads_lock
 209      * to ensure that we don't have >1 thread with pid=0 on the list at once
 210      */
 211     protect_control_stack_guard_page(th->pid,1);
 212     release_spinlock(&all_threads_lock);
 213
 214     sigprocmask(SIG_SETMASK,&oldset,0);
 215     th->pid=kid_pid;            /* child will not start until this is set */
 216 }
 217
 218 void create_initial_thread(lispobj initial_function) {
 219     struct thread *th=create_thread_struct(initial_function);
 220     pid_t kid_pid=getpid();
 221     if(th && kid_pid>0) {
 222         link_thread(th,kid_pid);
 223         initial_thread_trampoline(all_threads); /* no return */
 224     } else lose("can't create initial thread");
 225 }
 226
 227 #ifdef LISP_FEATURE_SB_THREAD
 228 pid_t create_thread(lispobj initial_function) {
 229     struct thread *th=create_thread_struct(initial_function);
 230     pid_t kid_pid=0;
 231
 232     if(th==0) return 0;
 233     kid_pid=clone(new_thread_trampoline,
 234                   (((void*)th->control_stack_start)+
 235                    THREAD_CONTROL_STACK_SIZE-4),
 236                   CLONE_FILES|SIG_THREAD_EXIT|CLONE_VM,th);
 237
 238     if(kid_pid>0) {
 239         link_thread(th,kid_pid);
 240         return th->pid;
 241     } else {
 242         os_invalidate((os_vm_address_t) th->control_stack_start,
 243                       ((sizeof (lispobj))
 244                        * (th->control_stack_end-th->control_stack_start)) +
 245                       BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 246                       32*SIGSTKSZ);
 247         return 0;
 248     }
 249 }
 250 #endif
 251
 252 /* unused */
 253 void destroy_thread (struct thread *th)
 254 {
 255     /* precondition: the unix task has already been killed and exited.
 256      * This is called by the parent or some other thread */
 257 #ifdef LISP_FEATURE_GENCGC
 258     gc_alloc_update_page_tables(0, &th->alloc_region);
 259 #endif
 260     get_spinlock(&all_threads_lock,th->pid);
 261     th->unbound_marker=0;       /* for debugging */
 262     if(th==all_threads)
 263         all_threads=th->next;
 264     else {
 265         struct thread *th1=all_threads;
 266         while(th1 && th1->next!=th) th1=th1->next;
 267         if(th1) th1->next=th->next;     /* unlink */
 268     }
 269     release_spinlock(&all_threads_lock);
 270     if(th && th->tls_cookie>=0) arch_os_thread_cleanup(th);
 271     os_invalidate((os_vm_address_t) th->control_stack_start,
 272                   ((sizeof (lispobj))
 273                    * (th->control_stack_end-th->control_stack_start)) +
 274                   BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 275                   32*SIGSTKSZ);
 276 }
 277
 278 struct thread *find_thread_by_pid(pid_t pid)
 279 {
 280     struct thread *th;
 281     for_each_thread(th)
 282         if(th->pid==pid) return th;
 283     return 0;
 284 }
 285
 286 #if defined LISP_FEATURE_SB_THREAD
 287 /* This is not needed unless #+SB-THREAD, as there's a trivial null
 288  * unithread definition. */
 289 void reap_dead_threads()
 290 {
 291     struct thread *th,*next,*prev=0;
 292     th=all_threads;
 293     while(th) {
 294         next=th->next;
 295         if(th->state==STATE_DEAD) {
 296             funcall1(SymbolFunction(HANDLE_THREAD_EXIT),make_fixnum(th->pid));
 297 #ifdef LISP_FEATURE_GENCGC
 298             gc_alloc_update_page_tables(0, &th->alloc_region);
 299 #endif
 300             get_spinlock(&all_threads_lock,th->pid);
 301             if(prev) prev->next=next;
 302             else all_threads=next;
 303             release_spinlock(&all_threads_lock);
 304             if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
 305             os_invalidate((os_vm_address_t) th->control_stack_start,
 306                           ((sizeof (lispobj))
 307                            * (th->control_stack_end-th->control_stack_start)) +
 308                           BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 309                           32*SIGSTKSZ);
 310         } else
 311             prev=th;
 312         th=next;
 313     }
 314 }
 315
 316 /* These are not needed unless #+SB-THREAD, and since sigwaitinfo()
 317  * doesn't seem to be easily available everywhere (OpenBSD...) it's
 318  * more trouble than it's worth to compile it when not needed. */
 319 void block_sigcont(void)
 320 {
 321     /* don't allow ourselves to receive SIGCONT while we're in the
 322      * "ambiguous" state of being on the queue but not actually stopped.
 323      */
 324     sigset_t newset;
 325     sigemptyset(&newset);
 326     sigaddset(&newset,SIG_DEQUEUE);
 327     sigprocmask(SIG_BLOCK, &newset, 0);
 328 }
 329
 330 void unblock_sigcont_and_sleep(void)
 331 {
 332     sigset_t set;
 333     sigemptyset(&set);
 334     sigaddset(&set,SIG_DEQUEUE);
 335     do {
 336         errno=0;
 337         sigwaitinfo(&set,0);
 338     }while(errno==EINTR);
 339     sigprocmask(SIG_UNBLOCK,&set,0);
 340 }
 341
 342 int interrupt_thread(pid_t pid, lispobj function)
 343 {
 344     union sigval sigval;
 345     sigval.sival_int=function;
 346
 347     return sigqueue(pid, SIG_INTERRUPT_THREAD, sigval);
 348 }
 349
 350 int signal_thread_to_dequeue (pid_t pid)
 351 {
 352     return kill (pid, SIG_DEQUEUE);
 353 }
 354
 355
 356 /* stopping the world is a two-stage process.  From this thread we signal
 357  * all the others with SIG_STOP_FOR_GC.  The handler for this signal does
 358  * the usual pseudo-atomic checks (we don't want to stop a thread while
 359  * it's in the middle of allocation) then kills _itself_ with SIGSTOP.
 360  */
 361
 362 void gc_stop_the_world()
 363 {
 364     /* stop all other threads by sending them SIG_STOP_FOR_GC */
 365     struct thread *p,*th=arch_os_get_current_thread();
 366     pid_t old_pid;
 367     int finished;
 368     do {
 369         finished=1;
 370         for(p=all_threads,old_pid=p->pid; p; p=p->next) {
 371             if(p==th) continue;
 372             if(p->state==STATE_RUNNING) {
 373                 p->state=STATE_STOPPING;
 374                 kill(p->pid,SIG_STOP_FOR_GC);
 375             }
 376             if((p->state!=STATE_STOPPED) &&
 377                (p->state!=STATE_DEAD)) {
 378                 finished=0;
 379             }
 380         }
 381         if(old_pid!=all_threads->pid) {
 382             finished=0;
 383         }
 384     } while(!finished);
 385 }
 386
 387 void gc_start_the_world()
 388 {
 389     struct thread *p,*th=arch_os_get_current_thread();
 390     /* if a resumed thread creates a new thread before we're done with
 391      * this loop, the new thread will get consed on the front of *
 392      * all_threads_lock, but it won't have been stopped so won't need
 393      * restarting */
 394     for(p=all_threads;p;p=p->next) {
 395         if((p==th) || (p->state==STATE_DEAD)) continue;
 396         p->state=STATE_RUNNING;
 397         kill(p->pid,SIG_STOP_FOR_GC);
 398     }
 399 }
 400 #endif