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 extern struct interrupt_data * global_interrupt_data;
  31 extern int linux_no_threads_p;
  32
  33 int
  34 initial_thread_trampoline(struct thread *th)
  35 {
  36     lispobj function;
  37 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  38     lispobj *args = NULL;
  39 #endif
  40
  41     function = th->unbound_marker;
  42     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  43     if(arch_os_thread_init(th)==0) return 1;
  44
  45     if(th->pid < 1) lose("th->pid not set up right");
  46     th->state=STATE_RUNNING;
  47 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
  48     return call_into_lisp_first_time(function,args,0);
  49 #else
  50     return funcall0(function);
  51 #endif
  52 }
  53
  54 /* this is the first thing that clone() runs in the child (which is
  55  * why the silly calling convention).  Basically it calls the user's
  56  * requested lisp function after doing arch_os_thread_init and
  57  * whatever other bookkeeping needs to be done
  58  */
  59
  60 #ifdef LISP_FEATURE_SB_THREAD
  61 int
  62 new_thread_trampoline(struct thread *th)
  63 {
  64     lispobj function;
  65     function = th->unbound_marker;
  66     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  67     if(arch_os_thread_init(th)==0) return 1;
  68
  69     /* wait here until our thread is linked into all_threads: see below */
  70     while(th->pid<1) sched_yield();
  71
  72     th->state=STATE_RUNNING;
  73     return funcall0(function);
  74 }
  75 #endif /* LISP_FEATURE_SB_THREAD */
  76
  77 /* this is called from any other thread to create the new one, and
  78  * initialize all parts of it that can be initialized from another
  79  * thread
  80  */
  81
  82 struct thread * create_thread_struct(lispobj initial_function) {
  83     union per_thread_data *per_thread;
  84     struct thread *th=0;        /*  subdue gcc */
  85     void *spaces=0;
  86
  87     /* may as well allocate all the spaces at once: it saves us from
  88      * having to decide what to do if only some of the allocations
  89      * succeed */
  90     spaces=os_validate(0,
  91                        THREAD_CONTROL_STACK_SIZE+
  92                        BINDING_STACK_SIZE+
  93                        ALIEN_STACK_SIZE+
  94                        dynamic_values_bytes+
  95                        32*SIGSTKSZ);
  96     if(!spaces)
  97          return NULL;
  98     per_thread=(union per_thread_data *)
  99         (spaces+
 100          THREAD_CONTROL_STACK_SIZE+
 101          BINDING_STACK_SIZE+
 102          ALIEN_STACK_SIZE);
 103
 104     if(all_threads) {
 105         memcpy(per_thread,arch_os_get_current_thread(),
 106                dynamic_values_bytes);
 107     } else {
 108 #ifdef LISP_FEATURE_SB_THREAD
 109         int i;
 110         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
 111             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
 112         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
 113             SetSymbolValue
 114                 (FREE_TLS_INDEX,
 115                  make_fixnum(MAX_INTERRUPTS+
 116                              sizeof(struct thread)/sizeof(lispobj)),
 117                  0);
 118 #define STATIC_TLS_INIT(sym,field) \
 119   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 120   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 121
 122         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 123         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 124         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 125         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
 126         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 127 #ifdef LISP_FEATURE_X86
 128         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 129         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 130 #endif
 131 #undef STATIC_TLS_INIT
 132 #endif
 133     }
 134
 135     th=&per_thread->thread;
 136     th->control_stack_start = spaces;
 137     th->binding_stack_start=
 138         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 139     th->control_stack_end = th->binding_stack_start;
 140     th->alien_stack_start=
 141         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 142     th->binding_stack_pointer=th->binding_stack_start;
 143     th->this=th;
 144     th->pid=0;
 145     th->state=STATE_STOPPED;
 146 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 147     th->alien_stack_pointer=((void *)th->alien_stack_start
 148                              + ALIEN_STACK_SIZE-N_WORD_BYTES);
 149 #else
 150     th->alien_stack_pointer=((void *)th->alien_stack_start);
 151 #endif
 152 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 153     th->pseudo_atomic_interrupted=0;
 154     th->pseudo_atomic_atomic=0;
 155 #endif
 156 #ifdef LISP_FEATURE_GENCGC
 157     gc_set_region_empty(&th->alloc_region);
 158 #endif
 159
 160 #ifndef LISP_FEATURE_SB_THREAD
 161     /* the tls-points-into-struct-thread trick is only good for threaded
 162      * sbcl, because unithread sbcl doesn't have tls.  So, we copy the
 163      * appropriate values from struct thread here, and make sure that
 164      * we use the appropriate SymbolValue macros to access any of the
 165      * variable quantities from the C runtime.  It's not quite OAOOM,
 166      * it just feels like it */
 167     SetSymbolValue(BINDING_STACK_START,(lispobj)th->binding_stack_start,th);
 168     SetSymbolValue(CONTROL_STACK_START,(lispobj)th->control_stack_start,th);
 169     SetSymbolValue(CONTROL_STACK_END,(lispobj)th->control_stack_end,th);
 170 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
 171     SetSymbolValue(BINDING_STACK_POINTER,(lispobj)th->binding_stack_pointer,th);
 172     SetSymbolValue(ALIEN_STACK,(lispobj)th->alien_stack_pointer,th);
 173     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,(lispobj)th->pseudo_atomic_atomic,th);
 174     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
 175 #else
 176     current_binding_stack_pointer=th->binding_stack_pointer;
 177     current_control_stack_pointer=th->control_stack_start;
 178 #endif
 179 #endif
 180     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
 181     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
 182     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
 183     bind_variable(INTERRUPT_PENDING, NIL,th);
 184     bind_variable(INTERRUPTS_ENABLED,T,th);
 185
 186     th->interrupt_data =
 187         os_validate(0,(sizeof (struct interrupt_data)));
 188     if(all_threads)
 189         memcpy(th->interrupt_data,
 190                arch_os_get_current_thread()->interrupt_data,
 191                sizeof (struct interrupt_data));
 192     else
 193         memcpy(th->interrupt_data,global_interrupt_data,
 194                sizeof (struct interrupt_data));
 195
 196     th->unbound_marker=initial_function;
 197     return th;
 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;
 232     pid_t kid_pid=0;
 233
 234     if(linux_no_threads_p) return 0;
 235     th=create_thread_struct(initial_function);
 236     if(th==0) return 0;
 237     kid_pid=clone(new_thread_trampoline,
 238                   (((void*)th->control_stack_start)+
 239                    THREAD_CONTROL_STACK_SIZE-16),
 240                   CLONE_FILES|SIG_THREAD_EXIT|CLONE_VM,th);
 241
 242     if(kid_pid>0) {
 243         link_thread(th,kid_pid);
 244         return th->pid;
 245     } else {
 246         os_invalidate((os_vm_address_t) th->control_stack_start,
 247                       ((sizeof (lispobj))
 248                        * (th->control_stack_end-th->control_stack_start)) +
 249                       BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 250                       32*SIGSTKSZ);
 251         return 0;
 252     }
 253 }
 254 #endif
 255
 256 struct thread *find_thread_by_pid(pid_t pid)
 257 {
 258     struct thread *th;
 259     for_each_thread(th)
 260         if(th->pid==pid) return th;
 261     return 0;
 262 }
 263
 264 #if defined LISP_FEATURE_SB_THREAD
 265 /* This is not needed unless #+SB-THREAD, as there's a trivial null
 266  * unithread definition. */
 267
 268 void mark_dead_threads()
 269 {
 270     pid_t kid;
 271     int status;
 272     while(1) {
 273         kid=waitpid(-1,&status,__WALL|WNOHANG);
 274         if(kid<=0) break;
 275         if(WIFEXITED(status) || WIFSIGNALED(status)) {
 276             struct thread *th=find_thread_by_pid(kid);
 277             if(th) th->state=STATE_DEAD;
 278         }
 279     }
 280 }
 281
 282 void reap_dead_threads()
 283 {
 284     struct thread *th,*next,*prev=0;
 285     th=all_threads;
 286     while(th) {
 287         next=th->next;
 288         if(th->state==STATE_DEAD) {
 289             funcall1(SymbolFunction(HANDLE_THREAD_EXIT),make_fixnum(th->pid));
 290 #ifdef LISP_FEATURE_GENCGC
 291             gc_alloc_update_page_tables(0, &th->alloc_region);
 292 #endif
 293             get_spinlock(&all_threads_lock,th->pid);
 294             if(prev) prev->next=next;
 295             else all_threads=next;
 296             release_spinlock(&all_threads_lock);
 297             if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
 298             os_invalidate((os_vm_address_t) th->control_stack_start,
 299                           ((sizeof (lispobj))
 300                            * (th->control_stack_end-th->control_stack_start)) +
 301                           BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 302                           32*SIGSTKSZ);
 303         } else
 304             prev=th;
 305         th=next;
 306     }
 307 }
 308
 309 /* These are not needed unless #+SB-THREAD, and since sigwaitinfo()
 310  * doesn't seem to be easily available everywhere (OpenBSD...) it's
 311  * more trouble than it's worth to compile it when not needed. */
 312 void block_sigcont(void)
 313 {
 314     /* don't allow ourselves to receive SIGCONT while we're in the
 315      * "ambiguous" state of being on the queue but not actually stopped.
 316      */
 317     sigset_t newset;
 318     sigemptyset(&newset);
 319     sigaddset(&newset,SIG_DEQUEUE);
 320     sigprocmask(SIG_BLOCK, &newset, 0);
 321 }
 322
 323 void unblock_sigcont_and_sleep(void)
 324 {
 325     sigset_t set;
 326     sigemptyset(&set);
 327     sigaddset(&set,SIG_DEQUEUE);
 328     do {
 329         errno=0;
 330         sigwaitinfo(&set,0);
 331     }while(errno==EINTR);
 332     sigprocmask(SIG_UNBLOCK,&set,0);
 333 }
 334
 335 int interrupt_thread(pid_t pid, lispobj function)
 336 {
 337     union sigval sigval;
 338     struct thread *th;
 339     sigval.sival_int=function;
 340     for_each_thread(th)
 341         if((th->pid==pid) && (th->state != STATE_DEAD))
 342             return sigqueue(pid, SIG_INTERRUPT_THREAD, sigval);
 343     errno=EPERM; return -1;
 344 }
 345
 346 int signal_thread_to_dequeue (pid_t pid)
 347 {
 348     return kill (pid, SIG_DEQUEUE);
 349 }
 350
 351
 352 /* stopping the world is a two-stage process.  From this thread we signal
 353  * all the others with SIG_STOP_FOR_GC.  The handler for this signal does
 354  * the usual pseudo-atomic checks (we don't want to stop a thread while
 355  * it's in the middle of allocation) then kills _itself_ with SIGSTOP.
 356  */
 357
 358 void gc_stop_the_world()
 359 {
 360     /* stop all other threads by sending them SIG_STOP_FOR_GC */
 361     struct thread *p,*th=arch_os_get_current_thread();
 362     pid_t old_pid;
 363     int finished;
 364     do {
 365         finished=1;
 366         for(p=all_threads,old_pid=p->pid; p; p=p->next) {
 367             if(p==th) continue;
 368             if(p->state==STATE_RUNNING) {
 369                 p->state=STATE_STOPPING;
 370                 if(kill(p->pid,SIG_STOP_FOR_GC)==-1) {
 371                     /* we can't kill the process; assume because it
 372                      * died already (and its parent is dead so never
 373                      * saw the SIGCHLD) */
 374                     p->state=STATE_DEAD;
 375                 }
 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