src/runtime/thread.c

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