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