int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr)
{
sigjmp_buf **switch_buf = switch_buf_ptr;
int n;
set_handler(SIGWINCH, (__sighandler_t) sig_handler,
SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
SIGVTALRM, -1);
*fork_buf_ptr = &initial_jmpbuf;
n = sigsetjmp(initial_jmpbuf, 1);
switch(n){
case INIT_JMP_NEW_THREAD:
new_thread_proc((void *) stack, new_thread_handler);
break;
case INIT_JMP_REMOVE_SIGSTACK:
remove_sigstack();
break;
case INIT_JMP_CALLBACK:
(*cb_proc)(cb_arg);
siglongjmp(*cb_back, 1);
break;
case INIT_JMP_HALT:
kmalloc_ok = 0;
return(0);
case INIT_JMP_REBOOT:
kmalloc_ok = 0;
return(1);
default:
panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
}
siglongjmp(**switch_buf, 1);
}
int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr)
{
sigjmp_buf **switch_buf = switch_buf_ptr;
int n;
*fork_buf_ptr = &initial_jmpbuf;
n = sigsetjmp(initial_jmpbuf, 1);
if(n == 0)
new_thread_proc((void *) stack, new_thread_handler);
else if(n == 1)
remove_sigstack();
else if(n == 2){
(*cb_proc)(cb_arg);
siglongjmp(*cb_back, 1);
}
else if(n == 3){
kmalloc_ok = 0;
return(0);
}
else if(n == 4){
kmalloc_ok = 0;
return(1);
}
siglongjmp(**switch_buf, 1);
}
void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
void (*handler)(int))
{
unsigned long flags;
sigjmp_buf switch_buf, fork_buf;
*switch_buf_ptr = &switch_buf;
*fork_buf_ptr = &fork_buf;
/* Somewhat subtle - siglongjmp restores the signal mask before doing
* the longjmp. This means that when jumping from one stack to another
* when the target stack has interrupts enabled, an interrupt may occur
* on the source stack. This is bad when starting up a process because
* it's not supposed to get timer ticks until it has been scheduled.
* So, we disable interrupts around the sigsetjmp to ensure that
* they can't happen until we get back here where they are safe.
*/
flags = get_signals();
block_signals();
if(sigsetjmp(fork_buf, 1) == 0)
new_thread_proc(stack, handler);
remove_sigstack();
set_signals(flags);
}
void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
void (*handler)(int))
{
sigjmp_buf switch_buf, fork_buf;
*switch_buf_ptr = &switch_buf;
*fork_buf_ptr = &fork_buf;
if(sigsetjmp(fork_buf, 1) == 0)
new_thread_proc(stack, handler);
remove_sigstack();
}