src/runtime/thread.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3 #include <sched.h>
   4 #include <stddef.h>
   5 #ifndef CLONE_PARENT            /* lameass glibc 2.2  doesn't define this */
   6 #define CLONE_PARENT 0x00008000 /* even though the manpage documents it */
   7 #endif
   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 #ifdef LISP_FEATURE_GENCGC
  17 #include "gencgc.h"
  18 #endif
  19 #include "dynbind.h"
  20 #include "genesis/cons.h"
  21 #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */
  22
  23 int dynamic_values_bytes=4096*sizeof(lispobj);  /* same for all threads */
  24 struct thread *all_threads;
  25 lispobj all_threads_lock;
  26 extern struct interrupt_data * global_interrupt_data;
  27
  28 void get_spinlock(lispobj *word,int value);
  29
  30 /* this is the first thing that clone() runs in the child (which is
  31  * why the silly calling convention).  Basically it calls the user's
  32  * requested lisp function after doing arch_os_thread_init and
  33  * whatever other bookkeeping needs to be done
  34  */
  35
  36 /* set go to 0 to stop the thread before it starts.  Convenient if you
  37 * want to attach a debugger to it before it does anything */
  38 volatile int go=1;
  39
  40 int
  41 new_thread_trampoline(struct thread *th)
  42 {
  43     lispobj function;
  44     function = th->unbound_marker;
  45     if(go==0) {
  46         fprintf(stderr, "/pausing 0x%lx(%d,%d) before new_thread_trampoline(0x%lx)\n",
  47                 (unsigned long)th,th->pid,getpid(),(unsigned long)function);
  48         while(go==0) ;
  49         fprintf(stderr, "/continue\n");
  50     }
  51     th->unbound_marker = UNBOUND_MARKER_WIDETAG;
  52     /* wait here until our thread is linked into all_threads: see below */
  53     while(th->pid<1) sched_yield();
  54
  55     if(arch_os_thread_init(th)==0)
  56         return 1;               /* failure.  no, really */
  57     return funcall0(function);
  58 }
  59
  60 /* this is called from any other thread to create the new one, and
  61  * initialize all parts of it that can be initialized from another
  62  * thread
  63  */
  64
  65 pid_t create_thread(lispobj initial_function) {
  66     union per_thread_data *per_thread;
  67     struct thread *th=0;        /*  subdue gcc */
  68     void *spaces=0;
  69     pid_t kid_pid;
  70
  71     /* may as well allocate all the spaces at once: it saves us from
  72      * having to decide what to do if only some of the allocations
  73      * succeed */
  74     spaces=os_validate(0,
  75                        THREAD_CONTROL_STACK_SIZE+
  76                        BINDING_STACK_SIZE+
  77                        ALIEN_STACK_SIZE+
  78                        dynamic_values_bytes+
  79                        32*SIGSTKSZ
  80                        );
  81     if(!spaces) goto cleanup;
  82     per_thread=(union per_thread_data *)
  83         (spaces+
  84          THREAD_CONTROL_STACK_SIZE+
  85          BINDING_STACK_SIZE+
  86          ALIEN_STACK_SIZE);
  87
  88     th=&per_thread->thread;
  89     if(all_threads) {
  90         memcpy(per_thread,arch_os_get_current_thread(),
  91                dynamic_values_bytes);
  92     } else {
  93         int i;
  94         for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
  95             per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
  96         if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
  97             SetSymbolValue
  98                 (FREE_TLS_INDEX,
  99                  make_fixnum(MAX_INTERRUPTS+
 100                              sizeof(struct thread)/sizeof(lispobj)),
 101                  0);
 102 #define STATIC_TLS_INIT(sym,field) \
 103   ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
 104   make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
 105
 106         STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
 107         STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
 108         STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
 109         STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
 110         STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
 111         STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
 112 #undef STATIC_TLS_INIT
 113     }
 114
 115     th->control_stack_start = spaces;
 116     th->binding_stack_start=
 117         (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
 118     th->alien_stack_start=
 119         (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
 120     th->binding_stack_pointer=th->binding_stack_start;
 121     th->this=th;
 122     th->pid=0;
 123 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
 124     th->alien_stack_pointer=((void *)th->alien_stack_start
 125                              + ALIEN_STACK_SIZE-4); /* naked 4.  FIXME */
 126 #else
 127     th->alien_stack_pointer=((void *)th->alien_stack_start);
 128 #endif
 129     th->pseudo_atomic_interrupted=0;
 130     /* runtime.c used to set PSEUDO_ATOMIC_ATOMIC =1 globally.  I'm not
 131      * sure why, but it appears to help */
 132     th->pseudo_atomic_atomic=make_fixnum(1);
 133     gc_set_region_empty(&th->alloc_region);
 134
 135     bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
 136     bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
 137     bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
 138     bind_variable(INTERRUPT_PENDING, NIL,th);
 139     bind_variable(INTERRUPTS_ENABLED,T,th);
 140
 141     th->interrupt_data=malloc(sizeof (struct interrupt_data));
 142     if(all_threads)
 143         memcpy(th->interrupt_data,arch_os_get_current_thread()->interrupt_data,
 144                sizeof (struct interrupt_data));
 145     else
 146         memcpy(th->interrupt_data,global_interrupt_data,
 147                sizeof (struct interrupt_data));
 148
 149
 150 #if defined(LISP_FEATURE_X86) && defined (LISP_FEATURE_LINUX)
 151     th->unbound_marker=initial_function;
 152     kid_pid=
 153         clone(new_thread_trampoline,
 154               (((void*)th->control_stack_start)+THREAD_CONTROL_STACK_SIZE-4),
 155               (((getpid()!=parent_pid)?(CLONE_PARENT):0)
 156                |CLONE_FILES|SIGALRM|CLONE_VM),th);
 157     if(kid_pid<=0)
 158         goto cleanup;
 159 #else
 160 #error this stuff presently only works on x86 Linux
 161 #endif
 162
 163     get_spinlock(&all_threads_lock,kid_pid);
 164     th->next=all_threads;
 165     all_threads=th;
 166     /* note that th->pid is 0 at this time.  We rely on all_threads_lock
 167      * to ensure that we don't have >1 thread with pid=0 on the list at once
 168      */
 169     protect_control_stack_guard_page(th->pid,1);
 170     all_threads_lock=0;
 171     th->pid=kid_pid;            /* child will not start until this is set */
 172     return th->pid;
 173  cleanup:
 174     /* if(th && th->tls_cookie>=0) os_free_tls_pointer(th); */
 175     if(spaces) os_invalidate(spaces,
 176                              THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+
 177                              ALIEN_STACK_SIZE+dynamic_values_bytes);
 178     return 0;
 179 }
 180
 181 void destroy_thread (struct thread *th)
 182 {
 183     /* precondition: the unix task has already been killed and exited.
 184      * This is called by the parent */
 185     gc_alloc_update_page_tables(0, &th->alloc_region);
 186     get_spinlock(&all_threads_lock,th->pid);
 187     if(th==all_threads)
 188         all_threads=th->next;
 189     else {
 190         struct thread *th1=all_threads;
 191         while(th1->next!=th) th1=th1->next;
 192         th1->next=th->next;     /* unlink */
 193     }
 194     all_threads_lock=0;
 195     if(th && th->tls_cookie>=0) arch_os_thread_cleanup(th);
 196     os_invalidate((os_vm_address_t) th->control_stack_start,
 197                   THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+
 198                   ALIEN_STACK_SIZE+dynamic_values_bytes+
 199                   32*SIGSTKSZ);
 200 }
 201
 202
 203 struct thread *find_thread_by_pid(pid_t pid)
 204 {
 205     struct thread *th;
 206     for_each_thread(th)
 207         if(th->pid==pid) return th;
 208     return 0;
 209 }
 210
 211
 212 void get_spinlock(lispobj *word,int value)
 213 {
 214     u32 eax=0;
 215     do {
 216         asm ("xor %0,%0;cmpxchg %1,%2"
 217              : "=a" (eax)
 218              : "r" (value), "m" (*word)
 219              : "memory", "cc");
 220     } while(eax!=0);
 221 }
 222
 223 void block_sigcont(void)
 224 {
 225     /* don't allow ourselves to receive SIGCONT while we're in the
 226      * "ambiguous" state of being on the queue but not actually stopped.
 227      */
 228     sigset_t newset;
 229     sigemptyset(&newset);
 230     sigaddset(&newset,SIGCONT);
 231     sigprocmask(SIG_BLOCK, &newset, 0);
 232 }
 233
 234 void unblock_sigcont_and_sleep(void)
 235 {
 236     sigset_t set;
 237     sigemptyset(&set);
 238     sigaddset(&set,SIGCONT);
 239     sigwaitinfo(&set,0);
 240     sigprocmask(SIG_UNBLOCK,&set,0);
 241 }
 242