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 #ifndef CLONE_PARENT            /* lameass glibc 2.2  doesn't define this */
   7 #define CLONE_PARENT 0x00008000 /* even though the manpage documents it */
   8 #endif
   9 #include "runtime.h"
  10 #include "sbcl.h"
  11 #include "validate.h"           /* for CONTROL_STACK_SIZE etc */
  12 #include "thread.h"
  13 #include "arch.h"
  14 #include "target-arch-os.h"
  15 #include "os.h"
  16 #include "globals.h"
  17 #ifdef LISP_FEATURE_GENCGC
  18 #include "gencgc.h"
  19 #endif
  20 #include "dynbind.h"
  21 #include "genesis/cons.h"
  22 #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */
  23
  24 int dynamic_values_bytes=4096*sizeof(lispobj);  /* same for all threads */
  25 struct thread *all_threads;
  26 lispobj all_threads_lock;
  27 int countdown_to_gc;
  28 extern struct interrupt_data * global_interrupt_data;
  29
  30 void get_spinlock(lispobj *word,int value);
  31
  32 /* this is the first thing that clone() runs in the child (which is
  33  * why the silly calling convention).  Basically it calls the user's
  34  * requested lisp function after doing arch_os_thread_init and
  35  * whatever other bookkeeping needs to be done
  36  */
  37
  38 /* set go to 0 to stop the thread before it starts.  Convenient if you
  39 * want to attach a debugger to it before it does anything */
  40 volatile int go=1;
  41
  42 int
  43 new_thread_trampoline(struct thread *th)
  44 {
  45     lispobj function;
  46     lispobj *args = NULL;
  47     function = th->unbound_marker;
  48     if(go==0) {
  49         fprintf(stderr, "/pausing 0x%lx(%d,%d) before new_thread_trampoline(0x%lx)\n",
  50                 (unsigned long)th,th->pid,getpid(),(unsigned long)function);
  51         while(go==0) ;
  52         fprintf(stderr, "/continue\n");
  53     }
  54     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  55 #ifdef LISP_FEATURE_SB_THREAD
  56     /* wait here until our thread is linked into all_threads: see below */
  57     while(th->pid<1) sched_yield();
  58 #else
  59     if(th->pid < 1)
  60         lose("th->pid not set up right");
  61 #endif
  62
  63     if(arch_os_thread_init(th)==0)
  64         return 1;               /* failure.  no, really */
  65 #if !defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_X86)
  66     return call_into_lisp_first_time(function,args,0);
  67 #else
  68     return funcall0(function);
  69 #endif
  70 }
  71
  72 /* this is called from any other thread to create the new one, and
  73  * initialize all parts of it that can be initialized from another
  74  * thread
  75  */
  76
  77 pid_t create_thread(lispobj initial_function) {
  78     union per_thread_data *per_thread;
  79     struct thread *th=0;        /*  subdue gcc */
  80     void *spaces=0;
  81     pid_t kid_pid;
  82
  83     /* may as well allocate all the spaces at once: it saves us from
  84      * having to decide what to do if only some of the allocations
  85      * succeed */
  86     spaces=os_validate(0,
  87                        THREAD_CONTROL_STACK_SIZE+
  88                        BINDING_STACK_SIZE+
  89                        ALIEN_STACK_SIZE+
  90                        dynamic_values_bytes+
  91                        32*SIGSTKSZ
  92                        );
  93     if(!spaces) goto cleanup;
  94     per_thread=(union per_thread_data *)
  95         (spaces+
  96          THREAD_CONTROL_STACK_SIZE+
  97          BINDING_STACK_SIZE+
  98          ALIEN_STACK_SIZE);
  99
 100     th=&per_thread->thread;
 101     if(all_threads) {
 102         memcpy(per_thread,arch_os_get_current_thread(),
 103                dynamic_values_bytes);
 104     } else {
 105 #ifdef LISP_FEATURE_SB_THREAD
 106         int i;
 107         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
 108             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
 109         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
 110             SetSymbolValue
 111                 (FREE_TLS_INDEX,
 112                  make_fixnum(MAX_INTERRUPTS+
 113                              sizeof(struct thread)/sizeof(lispobj)),
 114                  0);
 115 #define STATIC_TLS_INIT(sym,field) \
 116   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 117   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 118
 119         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 120         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 121         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 122         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
 123         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 124 #ifdef LISP_FEATURE_X86
 125         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 126         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 127 #endif
 128 #undef STATIC_TLS_INIT
 129 #endif
 130     }
 131
 132     th->control_stack_start = spaces;
 133     th->binding_stack_start=
 134         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 135     th->control_stack_end = th->binding_stack_start;
 136     th->alien_stack_start=
 137         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 138     th->binding_stack_pointer=th->binding_stack_start;
 139     th->this=th;
 140     th->pid=0;
 141 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 142     th->alien_stack_pointer=((void *)th->alien_stack_start
 143                              + ALIEN_STACK_SIZE-4); /* naked 4.  FIXME */
 144 #else
 145     th->alien_stack_pointer=((void *)th->alien_stack_start);
 146 #endif
 147 #ifdef LISP_FEATURE_X86
 148     th->pseudo_atomic_interrupted=0;
 149     /* runtime.c used to set PSEUDO_ATOMIC_ATOMIC =1 globally.  I'm not
 150      * sure why, but it appears to help */
 151     th->pseudo_atomic_atomic=make_fixnum(1);
 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,th->binding_stack_start,th);
 165     SetSymbolValue(CONTROL_STACK_START,th->control_stack_start,th);
 166     SetSymbolValue(CONTROL_STACK_END,th->control_stack_end,th);
 167 #ifdef LISP_FEATURE_X86
 168     SetSymbolValue(BINDING_STACK_POINTER,th->binding_stack_pointer,th);
 169     SetSymbolValue(ALIEN_STACK,th->alien_stack_pointer,th);
 170     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,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=os_validate(0,(sizeof (struct interrupt_data)));
 184     if(all_threads)
 185         memcpy(th->interrupt_data,
 186                arch_os_get_current_thread()->interrupt_data,
 187                sizeof (struct interrupt_data));
 188     else
 189         memcpy(th->interrupt_data,global_interrupt_data,
 190                sizeof (struct interrupt_data));
 191
 192     th->unbound_marker=initial_function;
 193 #ifdef LISP_FEATURE_SB_THREAD
 194 #if defined(LISP_FEATURE_X86) && defined (LISP_FEATURE_LINUX)
 195     kid_pid=
 196         clone(new_thread_trampoline,
 197               (((void*)th->control_stack_start)+THREAD_CONTROL_STACK_SIZE-4),
 198               (((getpid()!=parent_pid)?(CLONE_PARENT):0)
 199                |CLONE_FILES|SIGALRM|CLONE_VM),th);
 200     if(kid_pid<=0)
 201         goto cleanup;
 202 #else
 203 #error this stuff presently only works on x86 Linux
 204 #endif
 205 #else
 206     kid_pid=getpid();
 207 #endif
 208     get_spinlock(&all_threads_lock,kid_pid);
 209     th->next=all_threads;
 210     all_threads=th;
 211     /* note that th->pid is 0 at this time.  We rely on all_threads_lock
 212      * to ensure that we don't have >1 thread with pid=0 on the list at once
 213      */
 214     protect_control_stack_guard_page(th->pid,1);
 215     release_spinlock(&all_threads_lock);
 216     th->pid=kid_pid;            /* child will not start until this is set */
 217 #ifndef LISP_FEATURE_SB_THREAD
 218     new_thread_trampoline(all_threads); /*  call_into_lisp */
 219     lose("Clever child?  Idiot savant, verging on the.");
 220 #endif
 221
 222     return th->pid;
 223  cleanup:
 224     /* if(th && th->tls_cookie>=0) os_free_tls_pointer(th); */
 225     if(spaces) os_invalidate(spaces,
 226                              THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+
 227                              ALIEN_STACK_SIZE+dynamic_values_bytes);
 228     return 0;
 229 }
 230
 231 void destroy_thread (struct thread *th)
 232 {
 233     /* precondition: the unix task has already been killed and exited.
 234      * This is called by the parent */
 235 #ifdef LISP_FEATURE_GENCGC
 236     gc_alloc_update_page_tables(0, &th->alloc_region);
 237 #endif
 238     get_spinlock(&all_threads_lock,th->pid);
 239     if(countdown_to_gc>0) countdown_to_gc--;
 240     if(th==all_threads)
 241         all_threads=th->next;
 242     else {
 243         struct thread *th1=all_threads;
 244         while(th1->next!=th) th1=th1->next;
 245         th1->next=th->next;     /* unlink */
 246     }
 247     release_spinlock(&all_threads_lock);
 248     if(th && th->tls_cookie>=0) arch_os_thread_cleanup(th);
 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 }
 255
 256
 257 struct thread *find_thread_by_pid(pid_t pid)
 258 {
 259     struct thread *th;
 260     for_each_thread(th)
 261         if(th->pid==pid) return th;
 262     return 0;
 263 }
 264
 265 void block_sigcont(void)
 266 {
 267     /* don't allow ourselves to receive SIGCONT while we're in the
 268      * "ambiguous" state of being on the queue but not actually stopped.
 269      */
 270     sigset_t newset;
 271     sigemptyset(&newset);
 272     sigaddset(&newset,SIGCONT);
 273     sigprocmask(SIG_BLOCK, &newset, 0);
 274 }
 275
 276 /* This is not needed unless #+SB-THREAD, and since sigwaitinfo()
 277  * doesn't seem to be easily available everywhere (OpenBSD...) it's
 278  * more trouble than it's worth to compile it when not needed. */
 279 #if defined LISP_FEATURE_SB_THREAD
 280 void unblock_sigcont_and_sleep(void)
 281 {
 282     sigset_t set;
 283     sigemptyset(&set);
 284     sigaddset(&set,SIGCONT);
 285     sigwaitinfo(&set,0);
 286     sigprocmask(SIG_UNBLOCK,&set,0);
 287 }
 288
 289 int interrupt_thread(pid_t pid, lispobj function)
 290 {
 291     union sigval sigval;
 292     sigval.sival_int=function;
 293
 294     return sigqueue(pid, SIG_INTERRUPT_THREAD, sigval);
 295 }
 296
 297 void gc_stop_the_world()
 298 {
 299     /* stop all other threads by sending them SIG_STOP_FOR_GC */
 300     struct thread *p,*th=arch_os_get_current_thread();
 301     struct thread *tail=0;
 302     int finished=0;
 303     do {
 304         get_spinlock(&all_threads_lock,th->pid);
 305         if(tail!=all_threads) {
 306             /* new threads always get consed onto the front of all_threads,
 307              * and may be created by any thread that we haven't signalled
 308              * yet or hasn't received our signal and stopped yet.  So, check
 309              * for them on each time around */
 310             for(p=all_threads;p!=tail;p=p->next) {
 311                 if(p==th) continue;
 312                 countdown_to_gc++;
 313                 kill(p->pid,SIG_STOP_FOR_GC);
 314             }
 315             tail=all_threads;
 316         } else {
 317             finished=(countdown_to_gc==0);
 318         }
 319         release_spinlock(&all_threads_lock);
 320         sched_yield();
 321     } while(!finished);
 322 }
 323
 324 void gc_start_the_world()
 325 {
 326     struct thread *p,*th=arch_os_get_current_thread();
 327     get_spinlock(&all_threads_lock,th->pid);
 328     for(p=all_threads;p;p=p->next) {
 329         if(p==th) continue;
 330         kill(p->pid,SIGCONT);
 331     }
 332     release_spinlock(&all_threads_lock);
 333 }
 334 #endif