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#include <stdlib.h>
#include <stdio.h>
#include <sched.h>
#include <signal.h>
#include <stddef.h>
#include <errno.h>
#ifndef CLONE_PARENT /* lameass glibc 2.2 doesn't define this */
#define CLONE_PARENT 0x00008000 /* even though the manpage documents it */
#endif
#include "runtime.h"
#include "sbcl.h"
#include "validate.h" /* for CONTROL_STACK_SIZE etc */
#include "thread.h"
#include "arch.h"
#include "target-arch-os.h"
#include "os.h"
#include "globals.h"
#ifdef LISP_FEATURE_GENCGC
#include "gencgc.h"
#endif
#include "dynbind.h"
#include "genesis/cons.h"
#define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */
int dynamic_values_bytes=4096*sizeof(lispobj); /* same for all threads */
struct thread *all_threads;
lispobj all_threads_lock;
volatile int countdown_to_gc;
extern struct interrupt_data * global_interrupt_data;
void get_spinlock(lispobj *word,int value);
/* this is the first thing that clone() runs in the child (which is
* why the silly calling convention). Basically it calls the user's
* requested lisp function after doing arch_os_thread_init and
* whatever other bookkeeping needs to be done
*/
/* set go to 0 to stop the thread before it starts. Convenient if you
* want to attach a debugger to it before it does anything */
volatile int go=1;
int
new_thread_trampoline(struct thread *th)
{
lispobj function;
lispobj *args = NULL;
function = th->unbound_marker;
if(go==0) {
fprintf(stderr, "/pausing 0x%lx(%d,%d) before new_thread_trampoline(0x%lx)\n",
(unsigned long)th,th->pid,getpid(),(unsigned long)function);
while(go==0) ;
fprintf(stderr, "/continue\n");
}
th->unbound_marker = UNBOUND_MARKER_WIDETAG;
#ifdef LISP_FEATURE_SB_THREAD
/* wait here until our thread is linked into all_threads: see below */
while(th->pid<1) sched_yield();
#else
if(th->pid < 1)
lose("th->pid not set up right");
#endif
if(arch_os_thread_init(th)==0)
return 1; /* failure. no, really */
#if !defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_X86)
return call_into_lisp_first_time(function,args,0);
#else
return funcall0(function);
#endif
}
/* this is called from any other thread to create the new one, and
* initialize all parts of it that can be initialized from another
* thread
*/
pid_t create_thread(lispobj initial_function) {
union per_thread_data *per_thread;
struct thread *th=0; /* subdue gcc */
void *spaces=0;
pid_t kid_pid;
/* may as well allocate all the spaces at once: it saves us from
* having to decide what to do if only some of the allocations
* succeed */
spaces=os_validate(0,
THREAD_CONTROL_STACK_SIZE+
BINDING_STACK_SIZE+
ALIEN_STACK_SIZE+
dynamic_values_bytes+
32*SIGSTKSZ
);
if(!spaces) goto cleanup;
per_thread=(union per_thread_data *)
(spaces+
THREAD_CONTROL_STACK_SIZE+
BINDING_STACK_SIZE+
ALIEN_STACK_SIZE);
th=&per_thread->thread;
if(all_threads) {
memcpy(per_thread,arch_os_get_current_thread(),
dynamic_values_bytes);
} else {
#ifdef LISP_FEATURE_SB_THREAD
int i;
for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
SetSymbolValue
(FREE_TLS_INDEX,
make_fixnum(MAX_INTERRUPTS+
sizeof(struct thread)/sizeof(lispobj)),
0);
#define STATIC_TLS_INIT(sym,field) \
((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
#ifdef LISP_FEATURE_X86
STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic);
STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
#endif
#undef STATIC_TLS_INIT
#endif
}
th->control_stack_start = spaces;
th->binding_stack_start=
(lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE);
th->control_stack_end = th->binding_stack_start;
th->alien_stack_start=
(lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
th->binding_stack_pointer=th->binding_stack_start;
th->this=th;
th->pid=0;
#ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
th->alien_stack_pointer=((void *)th->alien_stack_start
+ ALIEN_STACK_SIZE-4); /* naked 4. FIXME */
#else
th->alien_stack_pointer=((void *)th->alien_stack_start);
#endif
#ifdef LISP_FEATURE_X86
th->pseudo_atomic_interrupted=0;
/* runtime.c used to set PSEUDO_ATOMIC_ATOMIC =1 globally. I'm not
* sure why, but it appears to help */
th->pseudo_atomic_atomic=make_fixnum(1);
#endif
#ifdef LISP_FEATURE_GENCGC
gc_set_region_empty(&th->alloc_region);
#endif
#ifndef LISP_FEATURE_SB_THREAD
/* the tls-points-into-struct-thread trick is only good for threaded
* sbcl, because unithread sbcl doesn't have tls. So, we copy the
* appropriate values from struct thread here, and make sure that
* we use the appropriate SymbolValue macros to access any of the
* variable quantities from the C runtime. It's not quite OAOOM,
* it just feels like it */
SetSymbolValue(BINDING_STACK_START,th->binding_stack_start,th);
SetSymbolValue(CONTROL_STACK_START,th->control_stack_start,th);
SetSymbolValue(CONTROL_STACK_END,th->control_stack_end,th);
#ifdef LISP_FEATURE_X86
SetSymbolValue(BINDING_STACK_POINTER,th->binding_stack_pointer,th);
SetSymbolValue(ALIEN_STACK,th->alien_stack_pointer,th);
SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,th->pseudo_atomic_atomic,th);
SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th);
#else
current_binding_stack_pointer=th->binding_stack_pointer;
current_control_stack_pointer=th->control_stack_start;
#endif
#endif
bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
bind_variable(INTERRUPT_PENDING, NIL,th);
bind_variable(INTERRUPTS_ENABLED,T,th);
th->interrupt_data=os_validate(0,(sizeof (struct interrupt_data)));
if(all_threads)
memcpy(th->interrupt_data,
arch_os_get_current_thread()->interrupt_data,
sizeof (struct interrupt_data));
else
memcpy(th->interrupt_data,global_interrupt_data,
sizeof (struct interrupt_data));
th->unbound_marker=initial_function;
#ifdef LISP_FEATURE_SB_THREAD
#if defined(LISP_FEATURE_X86) && defined (LISP_FEATURE_LINUX)
kid_pid=
clone(new_thread_trampoline,
(((void*)th->control_stack_start)+THREAD_CONTROL_STACK_SIZE-4),
(((getpid()!=parent_pid)?(CLONE_PARENT):0)
|CLONE_FILES|SIGALRM|CLONE_VM),th);
if(kid_pid<=0)
goto cleanup;
#else
#error this stuff presently only works on x86 Linux
#endif
#else
kid_pid=getpid();
#endif
get_spinlock(&all_threads_lock,kid_pid);
th->next=all_threads;
all_threads=th;
/* note that th->pid is 0 at this time. We rely on all_threads_lock
* to ensure that we don't have >1 thread with pid=0 on the list at once
*/
protect_control_stack_guard_page(th->pid,1);
release_spinlock(&all_threads_lock);
th->pid=kid_pid; /* child will not start until this is set */
#ifndef LISP_FEATURE_SB_THREAD
new_thread_trampoline(all_threads); /* call_into_lisp */
lose("Clever child? Idiot savant, verging on the.");
#endif
return th->pid;
cleanup:
/* if(th && th->tls_cookie>=0) os_free_tls_pointer(th); */
if(spaces) os_invalidate(spaces,
THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+
ALIEN_STACK_SIZE+dynamic_values_bytes);
return 0;
}
void destroy_thread (struct thread *th)
{
/* precondition: the unix task has already been killed and exited.
* This is called by the parent */
#ifdef LISP_FEATURE_GENCGC
gc_alloc_update_page_tables(0, &th->alloc_region);
#endif
get_spinlock(&all_threads_lock,th->pid);
if(countdown_to_gc>0) countdown_to_gc--;
if(th==all_threads)
all_threads=th->next;
else {
struct thread *th1=all_threads;
while(th1->next!=th) th1=th1->next;
th1->next=th->next; /* unlink */
}
release_spinlock(&all_threads_lock);
if(th && th->tls_cookie>=0) arch_os_thread_cleanup(th);
os_invalidate((os_vm_address_t) th->control_stack_start,
((sizeof (lispobj))
* (th->control_stack_end-th->control_stack_start)) +
BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
32*SIGSTKSZ);
}
struct thread *find_thread_by_pid(pid_t pid)
{
struct thread *th;
for_each_thread(th)
if(th->pid==pid) return th;
return 0;
}
void block_sigcont(void)
{
/* don't allow ourselves to receive SIGCONT while we're in the
* "ambiguous" state of being on the queue but not actually stopped.
*/
sigset_t newset;
sigemptyset(&newset);
sigaddset(&newset,SIG_DEQUEUE);
sigprocmask(SIG_BLOCK, &newset, 0);
}
/* This is not needed unless #+SB-THREAD, and since sigwaitinfo()
* doesn't seem to be easily available everywhere (OpenBSD...) it's
* more trouble than it's worth to compile it when not needed. */
#if defined LISP_FEATURE_SB_THREAD
void unblock_sigcont_and_sleep(void)
{
sigset_t set;
sigemptyset(&set);
sigaddset(&set,SIG_DEQUEUE);
do {
errno=0;
sigwaitinfo(&set,0);
}while(errno==EINTR);
sigprocmask(SIG_UNBLOCK,&set,0);
}
int interrupt_thread(pid_t pid, lispobj function)
{
union sigval sigval;
sigval.sival_int=function;
return sigqueue(pid, SIG_INTERRUPT_THREAD, sigval);
}
/* stopping the world is a two-stage process. From this thread we signal
* all the others with SIG_STOP_FOR_GC. The handler for this thread does
* the usual pseudo-atomic checks (we don't want to stop a thread while
* it's in the middle of allocation) then kills _itself_ with SIGSTOP.
* At any given time, countdown_to_gc should reflect the number of threads
* signalled but which haven't yet come to rest
*/
void gc_stop_the_world()
{
/* stop all other threads by sending them SIG_STOP_FOR_GC */
struct thread *p,*th=arch_os_get_current_thread();
struct thread *tail=0;
int finished=0;
do {
get_spinlock(&all_threads_lock,th->pid);
if(tail!=all_threads) {
/* new threads always get consed onto the front of all_threads,
* and may be created by any thread that we haven't signalled
* yet or hasn't received our signal and stopped yet. So, check
* for them on each time around */
for(p=all_threads;p!=tail;p=p->next) {
if(p==th) continue;
countdown_to_gc++;
kill(p->pid,SIG_STOP_FOR_GC);
}
tail=all_threads;
} else {
finished=(countdown_to_gc==0);
}
release_spinlock(&all_threads_lock);
sched_yield();
} while(!finished);
}
void gc_start_the_world()
{
struct thread *p,*th=arch_os_get_current_thread();
get_spinlock(&all_threads_lock,th->pid);
for(p=all_threads;p;p=p->next) {
if(p==th) continue;
kill(p->pid,SIGCONT);
}
release_spinlock(&all_threads_lock);
}
#endif