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 extern struct interrupt_data * global_interrupt_data;
  28
  29 void get_spinlock(lispobj *word,int value);
  30
  31 /* this is the first thing that clone() runs in the child (which is
  32  * why the silly calling convention).  Basically it calls the user's
  33  * requested lisp function after doing arch_os_thread_init and
  34  * whatever other bookkeeping needs to be done
  35  */
  36
  37 /* set go to 0 to stop the thread before it starts.  Convenient if you
  38 * want to attach a debugger to it before it does anything */
  39 volatile int go=1;
  40
  41 int
  42 new_thread_trampoline(struct thread *th)
  43 {
  44     lispobj function;
  45     lispobj *args = NULL;
  46     function = th->unbound_marker;
  47     if(go==0) {
  48         fprintf(stderr, "/pausing 0x%lx(%d,%d) before new_thread_trampoline(0x%lx)\n",
  49                 (unsigned long)th,th->pid,getpid(),(unsigned long)function);
  50         while(go==0) ;
  51         fprintf(stderr, "/continue\n");
  52     }
  53     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  54 #ifdef LISP_FEATURE_SB_THREAD
  55     /* wait here until our thread is linked into all_threads: see below */
  56     while(th->pid<1) sched_yield();
  57 #else
  58     if(th->pid < 1)
  59         lose("th->pid not set up right");
  60 #endif
  61
  62     if(arch_os_thread_init(th)==0)
  63         return 1;               /* failure.  no, really */
  64 #if !defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_X86)
  65     return call_into_lisp_first_time(function,args,0);
  66 #else
  67     return funcall0(function);
  68 #endif
  69 }
  70
  71 /* this is called from any other thread to create the new one, and
  72  * initialize all parts of it that can be initialized from another
  73  * thread
  74  */
  75
  76 pid_t create_thread(lispobj initial_function) {
  77     union per_thread_data *per_thread;
  78     struct thread *th=0;        /*  subdue gcc */
  79     void *spaces=0;
  80     pid_t kid_pid;
  81
  82     /* may as well allocate all the spaces at once: it saves us from
  83      * having to decide what to do if only some of the allocations
  84      * succeed */
  85     spaces=os_validate(0,
  86                        THREAD_CONTROL_STACK_SIZE+
  87                        BINDING_STACK_SIZE+
  88                        ALIEN_STACK_SIZE+
  89                        dynamic_values_bytes+
  90                        32*SIGSTKSZ
  91                        );
  92     if(!spaces) goto cleanup;
  93     per_thread=(union per_thread_data *)
  94         (spaces+
  95          THREAD_CONTROL_STACK_SIZE+
  96          BINDING_STACK_SIZE+
  97          ALIEN_STACK_SIZE);
  98
  99     th=&per_thread->thread;
 100     if(all_threads) {
 101         memcpy(per_thread,arch_os_get_current_thread(),
 102                dynamic_values_bytes);
 103     } else {
 104 #ifdef LISP_FEATURE_SB_THREAD
 105         int i;
 106         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
 107             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
 108         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
 109             SetSymbolValue
 110                 (FREE_TLS_INDEX,
 111                  make_fixnum(MAX_INTERRUPTS+
 112                              sizeof(struct thread)/sizeof(lispobj)),
 113                  0);
 114 #define STATIC_TLS_INIT(sym,field) \
 115   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 116   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 117
 118         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 119         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 120         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 121         STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
 122         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 123 #ifdef LISP_FEATURE_X86
 124         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 125         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 126 #endif
 127 #undef STATIC_TLS_INIT
 128 #endif
 129     }
 130
 131     th->control_stack_start = spaces;
 132     th->binding_stack_start=
 133         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 134     th->control_stack_end = th->binding_stack_start;
 135     th->alien_stack_start=
 136         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 137     th->binding_stack_pointer=th->binding_stack_start;
 138     th->this=th;
 139     th->pid=0;
 140 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 141     th->alien_stack_pointer=((void *)th->alien_stack_start
 142                              + ALIEN_STACK_SIZE-4); /* naked 4.  FIXME */
 143 #else
 144     th->alien_stack_pointer=((void *)th->alien_stack_start);
 145 #endif
 146 #ifdef LISP_FEATURE_X86
 147     th->pseudo_atomic_interrupted=0;
 148     /* runtime.c used to set PSEUDO_ATOMIC_ATOMIC =1 globally.  I'm not
 149      * sure why, but it appears to help */
 150     th->pseudo_atomic_atomic=make_fixnum(1);
 151 #endif
 152 #ifdef LISP_FEATURE_GENCGC
 153     gc_set_region_empty(&th->alloc_region);
 154 #endif
 155
 156 #ifndef LISP_FEATURE_SB_THREAD
 157     /* the tls-points-into-struct-thread trick is only good for threaded
 158      * sbcl, because unithread sbcl doesn't have tls.  So, we copy the
 159      * appropriate values from struct thread here, and make sure that
 160      * we use the appropriate SymbolValue macros to access any of the
 161      * variable quantities from the C runtime.  It's not quite OAOOM,
 162      * it just feels like it */
 163     SetSymbolValue(BINDING_STACK_START,th->binding_stack_start,th);
 164     SetSymbolValue(CONTROL_STACK_START,th->control_stack_start,th);
 165     SetSymbolValue(CONTROL_STACK_END,th->control_stack_end,th);
 166 #ifdef LISP_FEATURE_X86
 167     SetSymbolValue(BINDING_STACK_POINTER,th->binding_stack_pointer,th);
 168     SetSymbolValue(ALIEN_STACK,th->alien_stack_pointer,th);
 169     SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,th->pseudo_atomic_atomic,th);
 170     SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
 171 #else
 172     current_binding_stack_pointer=th->binding_stack_pointer;
 173     current_control_stack_pointer=th->control_stack_start;
 174 #endif
 175 #endif
 176     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
 177     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
 178     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
 179     bind_variable(INTERRUPT_PENDING, NIL,th);
 180     bind_variable(INTERRUPTS_ENABLED,T,th);
 181
 182     th->interrupt_data=os_validate(0,(sizeof (struct interrupt_data)));
 183     if(all_threads)
 184         memcpy(th->interrupt_data,
 185                arch_os_get_current_thread()->interrupt_data,
 186                sizeof (struct interrupt_data));
 187     else
 188         memcpy(th->interrupt_data,global_interrupt_data,
 189                sizeof (struct interrupt_data));
 190
 191     th->unbound_marker=initial_function;
 192 #ifdef LISP_FEATURE_SB_THREAD
 193 #if defined(LISP_FEATURE_X86) && defined (LISP_FEATURE_LINUX)
 194     kid_pid=
 195         clone(new_thread_trampoline,
 196               (((void*)th->control_stack_start)+THREAD_CONTROL_STACK_SIZE-4),
 197               (((getpid()!=parent_pid)?(CLONE_PARENT):0)
 198                |CLONE_FILES|SIGALRM|CLONE_VM),th);
 199     if(kid_pid<=0)
 200         goto cleanup;
 201 #else
 202 #error this stuff presently only works on x86 Linux
 203 #endif
 204 #else
 205     kid_pid=getpid();
 206 #endif
 207     get_spinlock(&all_threads_lock,kid_pid);
 208     th->next=all_threads;
 209     all_threads=th;
 210     /* note that th->pid is 0 at this time.  We rely on all_threads_lock
 211      * to ensure that we don't have >1 thread with pid=0 on the list at once
 212      */
 213     protect_control_stack_guard_page(th->pid,1);
 214     all_threads_lock=0;
 215     th->pid=kid_pid;            /* child will not start until this is set */
 216 #ifndef LISP_FEATURE_SB_THREAD
 217     new_thread_trampoline(all_threads); /*  call_into_lisp */
 218     lose("Clever child?  Idiot savant, verging on the.");
 219 #endif
 220
 221     return th->pid;
 222  cleanup:
 223     /* if(th && th->tls_cookie>=0) os_free_tls_pointer(th); */
 224     if(spaces) os_invalidate(spaces,
 225                              THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+
 226                              ALIEN_STACK_SIZE+dynamic_values_bytes);
 227     return 0;
 228 }
 229
 230 void destroy_thread (struct thread *th)
 231 {
 232     /* precondition: the unix task has already been killed and exited.
 233      * This is called by the parent */
 234 #ifdef LISP_FEATURE_GENCGC
 235     gc_alloc_update_page_tables(0, &th->alloc_region);
 236 #endif
 237     get_spinlock(&all_threads_lock,th->pid);
 238     if(th==all_threads)
 239         all_threads=th->next;
 240     else {
 241         struct thread *th1=all_threads;
 242         while(th1->next!=th) th1=th1->next;
 243         th1->next=th->next;     /* unlink */
 244     }
 245     all_threads_lock=0;
 246     if(th && th->tls_cookie>=0) arch_os_thread_cleanup(th);
 247     os_invalidate((os_vm_address_t) th->control_stack_start,
 248                   ((sizeof (lispobj))
 249                    * (th->control_stack_end-th->control_stack_start)) +
 250                   BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
 251                   32*SIGSTKSZ);
 252 }
 253
 254
 255 struct thread *find_thread_by_pid(pid_t pid)
 256 {
 257     struct thread *th;
 258     for_each_thread(th)
 259         if(th->pid==pid) return th;
 260     return 0;
 261 }
 262
 263 void block_sigcont(void)
 264 {
 265     /* don't allow ourselves to receive SIGCONT while we're in the
 266      * "ambiguous" state of being on the queue but not actually stopped.
 267      */
 268     sigset_t newset;
 269     sigemptyset(&newset);
 270     sigaddset(&newset,SIGCONT);
 271     sigprocmask(SIG_BLOCK, &newset, 0);
 272 }
 273
 274 /* This is not needed unless #+SB-THREAD, and since sigwaitinfo()
 275  * doesn't seem to be easily available everywhere (OpenBSD...) it's
 276  * more trouble than it's worth to compile it when not needed. */
 277 #if defined LISP_FEATURE_SB_THREAD
 278 void unblock_sigcont_and_sleep(void)
 279 {
 280     sigset_t set;
 281     sigemptyset(&set);
 282     sigaddset(&set,SIGCONT);
 283     sigwaitinfo(&set,0);
 284     sigprocmask(SIG_UNBLOCK,&set,0);
 285 }
 286 #endif