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 "runtime.h"
   9 #include "sbcl.h"
  10 #include "validate.h"           /* for CONTROL_STACK_SIZE etc */
  11 #include "thread.h"
  12 #include "arch.h"
  13 #include "target-arch-os.h"
  14 #include "os.h"
  15 #include "globals.h"
  16 #include "dynbind.h"
  17 #include "genesis/cons.h"
  18 #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */
  19
  20 int dynamic_values_bytes=4096*sizeof(lispobj);  /* same for all threads */
  21 struct thread *all_threads;
  22 volatile lispobj all_threads_lock;
  23 extern struct interrupt_data * global_interrupt_data;
  24
  25 void get_spinlock(lispobj *word,int value);
  26
  27 int
  28 initial_thread_trampoline(struct thread *th)
  29 {
  30     lispobj function;
  31     lispobj *args = NULL;
  32     function = th->unbound_marker;
  33     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  34     if(arch_os_thread_init(th)==0) return 1;
  35
  36     if(th->pid < 1) lose("th->pid not set up right");
  37     th->state=STATE_RUNNING;
  38 #if defined(LISP_FEATURE_X86)
  39     return call_into_lisp_first_time(function,args,0);
  40 #else
  41     return funcall0(function);
  42 #endif
  43 }
  44
  45 /* this is the first thing that clone() runs in the child (which is
  46  * why the silly calling convention).  Basically it calls the user's
  47  * requested lisp function after doing arch_os_thread_init and
  48  * whatever other bookkeeping needs to be done
  49  */
  50
  51 #ifdef LISP_FEATURE_SB_THREAD
  52 int
  53 new_thread_trampoline(struct thread *th)
  54 {
  55     lispobj function;
  56     function = th->unbound_marker;
  57     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  58     if(arch_os_thread_init(th)==0) return 1;
  59
  60     /* wait here until our thread is linked into all_threads: see below */
  61     while(th->pid<1) sched_yield();
  62
  63     th->state=STATE_RUNNING;
  64     return funcall0(function);
  65 }
  66 #endif /* LISP_FEATURE_SB_THREAD */
  67
  68 /* this is called from any other thread to create the new one, and
  69  * initialize all parts of it that can be initialized from another
  70  * thread
  71  */
  72
  73 struct thread * create_thread_struct(lispobj initial_function) {
  74     union per_thread_data *per_thread;
  75     struct thread *th=0;        /*  subdue gcc */
  76     void *spaces=0;
  77
  78     /* may as well allocate all the spaces at once: it saves us from
  79      * having to decide what to do if only some of the allocations
  80      * succeed */
  81     spaces=os_validate(0,
  82                        THREAD_CONTROL_STACK_SIZE+
  83                        BINDING_STACK_SIZE+
  84                        ALIEN_STACK_SIZE+
  85                        dynamic_values_bytes+
  86                        32*SIGSTKSZ
  87                        );
  88     if(!spaces) goto cleanup;
  89     per_thread=(union per_thread_data *)
  90         (spaces+
  91          THREAD_CONTROL_STACK_SIZE+
  92          BINDING_STACK_SIZE+
  93          ALIEN_STACK_SIZE);
  94
  95     th=&per_thread->thread;
  96     if(all_threads) {
  97         memcpy(per_thread,arch_os_get_current_thread(),
  98                dynamic_values_bytes);
  99     } else {
 100 #ifdef LISP_FEATURE_SB_THREAD
 101         int i;
 102         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
 103             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
 104         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
 105             SetSymbolValue
 106                 (FREE_TLS_INDEX,
 107                  make_fixnum(MAX_INTERRUPTS+
 108                              sizeof(struct thread)/sizeof(lispobj)),
 109                  0);
 110 #define STATIC_TLS_INIT(sym,field) \
 111   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 112   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 113
 114         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 115         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 116         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 117         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
 118         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 119 #ifdef LISP_FEATURE_X86
 120         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 121         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 122 #endif
 123 #undef STATIC_TLS_INIT
 124 #endif
 125     }
 126
 127     th->control_stack_start = spaces;
 128     th->binding_stack_start=
 129         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 130     th->control_stack_end = th->binding_stack_start;
 131     th->alien_stack_start=
 132         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 133     th->binding_stack_pointer=th->binding_stack_start;
 134     th->this=th;
 135     th->pid=0;
 136     th->state=STATE_STOPPED;
 137 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 138     th->alien_stack_pointer=((void *)th->alien_stack_start
 139                              + ALIEN_STACK_SIZE-4); /* naked 4.  FIXME */
 140 #else
 141     th->alien_stack_pointer=((void *)th->alien_stack_start);
 142 #endif
 143 #ifdef LISP_FEATURE_X86
 144     th->pseudo_atomic_interrupted=0;
 145     th->pseudo_atomic_atomic=0;
 146 #endif
 147 #ifdef LISP_FEATURE_GENCGC
 148     gc_set_region_empty(&th->alloc_region);
 149 #endif
 150
 151 #ifndef LISP_FEATURE_SB_THREAD
 152     /* the tls-points-into-struct-thread trick is only good for threaded
 153      * sbcl, because unithread sbcl doesn't have tls.  So, we copy the
 154      * appropriate values from struct thread here, and make sure that
 155      * we use the appropriate SymbolValue macros to access any of the
 156      * variable quantities from the C runtime.  It's not quite OAOOM,
 157      * it just feels like it */
 158     SetSymbolValue(BINDING_STACK_START,th->binding_stack_start,th);
 159     SetSymbolValue(CONTROL_STACK_START,th->control_stack_start,th);
 160     SetSymbolValue(CONTROL_STACK_END,th->control_stack_end,th);
 161 #ifdef LISP_FEATURE_X86
 162     SetSymbolValue(BINDING_STACK_POINTER,th->binding_stack_pointer,th);
 163     SetSymbolValue(ALIEN_STACK,th->alien_stack_pointer,th);
 164     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,th->pseudo_atomic_atomic,th);
 165     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
 166 #else
 167     current_binding_stack_pointer=th->binding_stack_pointer;
 168     current_control_stack_pointer=th->control_stack_start;
 169 #endif
 170 #endif
 171     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
 172     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
 173     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
 174     bind_variable(INTERRUPT_PENDING, NIL,th);
 175     bind_variable(INTERRUPTS_ENABLED,T,th);
 176
 177     th->interrupt_data=os_validate(0,(sizeof (struct interrupt_data)));
 178     if(all_threads)
 179         memcpy(th->interrupt_data,
 180                arch_os_get_current_thread()->interrupt_data,
 181                sizeof (struct interrupt_data));
 182     else
 183         memcpy(th->interrupt_data,global_interrupt_data,
 184                sizeof (struct interrupt_data));
 185
 186     th->unbound_marker=initial_function;
 187     return th;
 188  cleanup:
 189     /* if(th && th->tls_cookie>=0) os_free_tls_pointer(th); */
 190     if(spaces) os_invalidate(spaces,
 191                              THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+
 192                              ALIEN_STACK_SIZE+dynamic_values_bytes);
 193     return 0;
 194 }
 195
 196 void link_thread(struct thread *th,pid_t kid_pid)
 197 {
 198     get_spinlock(&all_threads_lock,kid_pid);
 199     th->next=all_threads;
 200     all_threads=th;
 201     /* note that th->pid is 0 at this time.  We rely on all_threads_lock
 202      * to ensure that we don't have >1 thread with pid=0 on the list at once
 203      */
 204     protect_control_stack_guard_page(th->pid,1);
 205     release_spinlock(&all_threads_lock);
 206     th->pid=kid_pid;            /* child will not start until this is set */
 207 }
 208
 209 void create_initial_thread(lispobj initial_function) {
 210     struct thread *th=create_thread_struct(initial_function);
 211     pid_t kid_pid=getpid();
 212     if(th && kid_pid>0) {
 213         link_thread(th,kid_pid);
 214         initial_thread_trampoline(all_threads); /* no return */
 215     } else lose("can't create initial thread");
 216 }
 217
 218 #ifdef LISP_FEATURE_LINUX
 219 pid_t create_thread(lispobj initial_function) {
 220     struct thread *th=create_thread_struct(initial_function);
 221     pid_t kid_pid=clone(new_thread_trampoline,
 222                         (((void*)th->control_stack_start)+
 223                          THREAD_CONTROL_STACK_SIZE-4),
 224                         CLONE_FILES|SIG_THREAD_EXIT|CLONE_VM,th);
 225
 226     if(th && kid_pid>0) {
 227         link_thread(th,kid_pid);
 228         return th->pid;
 229     } else {
 230         destroy_thread(th);
 231         return 0;
 232     }
 233 }
 234 #endif
 235
 236 void destroy_thread (struct thread *th)
 237 {
 238     /* precondition: the unix task has already been killed and exited.
 239      * This is called by the parent */
 240 #ifdef LISP_FEATURE_GENCGC
 241     gc_alloc_update_page_tables(0, &th->alloc_region);
 242 #endif
 243     get_spinlock(&all_threads_lock,th->pid);
 244     th->state=STATE_STOPPED;
 245     if(th==all_threads)
 246         all_threads=th->next;
 247     else {
 248         struct thread *th1=all_threads;
 249         while(th1 && th1->next!=th) th1=th1->next;
 250         if(th1) th1->next=th->next;     /* unlink */
 251     }
 252     release_spinlock(&all_threads_lock);
 253     if(th && th->tls_cookie>=0) arch_os_thread_cleanup(th);
 254     os_invalidate((os_vm_address_t) th->control_stack_start,
 255                   ((sizeof (lispobj))
 256                    * (th->control_stack_end-th->control_stack_start)) +
 257                   BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 258                   32*SIGSTKSZ);
 259 }
 260
 261
 262 struct thread *find_thread_by_pid(pid_t pid)
 263 {
 264     struct thread *th;
 265     for_each_thread(th)
 266         if(th->pid==pid) return th;
 267     return 0;
 268 }
 269
 270 /* These are not needed unless #+SB-THREAD, and since sigwaitinfo()
 271  * doesn't seem to be easily available everywhere (OpenBSD...) it's
 272  * more trouble than it's worth to compile it when not needed. */
 273 #if defined LISP_FEATURE_SB_THREAD
 274 void block_sigcont(void)
 275 {
 276     /* don't allow ourselves to receive SIGCONT while we're in the
 277      * "ambiguous" state of being on the queue but not actually stopped.
 278      */
 279     sigset_t newset;
 280     sigemptyset(&newset);
 281     sigaddset(&newset,SIG_DEQUEUE);
 282     sigprocmask(SIG_BLOCK, &newset, 0);
 283 }
 284
 285 void unblock_sigcont_and_sleep(void)
 286 {
 287     sigset_t set;
 288     sigemptyset(&set);
 289     sigaddset(&set,SIG_DEQUEUE);
 290     do {
 291         errno=0;
 292         sigwaitinfo(&set,0);
 293     }while(errno==EINTR);
 294     sigprocmask(SIG_UNBLOCK,&set,0);
 295 }
 296
 297 int interrupt_thread(pid_t pid, lispobj function)
 298 {
 299     union sigval sigval;
 300     sigval.sival_int=function;
 301
 302     return sigqueue(pid, SIG_INTERRUPT_THREAD, sigval);
 303 }
 304
 305 int signal_thread_to_dequeue (pid_t pid)
 306 {
 307     return kill (pid, SIG_DEQUEUE);
 308 }
 309
 310
 311 /* stopping the world is a two-stage process.  From this thread we signal
 312  * all the others with SIG_STOP_FOR_GC.  The handler for this thread does
 313  * the usual pseudo-atomic checks (we don't want to stop a thread while
 314  * it's in the middle of allocation) then kills _itself_ with SIGSTOP.
 315  */
 316
 317 void gc_stop_the_world()
 318 {
 319     /* stop all other threads by sending them SIG_STOP_FOR_GC */
 320     struct thread *p,*th=arch_os_get_current_thread();
 321     pid_t old_pid;
 322     int finished=0;
 323     do {
 324         get_spinlock(&all_threads_lock,th->pid);
 325         for(p=all_threads,old_pid=p->pid; p; p=p->next) {
 326             if(p==th) continue;
 327             if(p->state!=STATE_RUNNING) continue;
 328             p->state=STATE_STOPPING;
 329             kill(p->pid,SIG_STOP_FOR_GC);
 330         }
 331         release_spinlock(&all_threads_lock);
 332         sched_yield();
 333         /* if everything has stopped, and there is no possibility that
 334          * a new thread has been created, we're done.  Otherwise go
 335          * round again and signal anything that sprang up since last
 336          * time  */
 337         if(old_pid==all_threads->pid) {
 338             finished=1;
 339             for_each_thread(p)
 340                 finished = finished &&
 341                 ((p==th) || (p->state==STATE_STOPPED));
 342         }
 343     } while(!finished);
 344 }
 345
 346 void gc_start_the_world()
 347 {
 348     struct thread *p,*th=arch_os_get_current_thread();
 349     get_spinlock(&all_threads_lock,th->pid);
 350     for(p=all_threads;p;p=p->next) {
 351         if(p==th) continue;
 352         p->state=STATE_RUNNING;
 353         kill(p->pid,SIG_STOP_FOR_GC);
 354     }
 355     release_spinlock(&all_threads_lock);
 356 }
 357 #endif