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