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