void psleep(void *event)
{
irqflags_t irq = di();
#ifdef DEBUG
kprintf("psleep(0x%x)", event); /* WRS */
#endif
switch (udata.u_ptab->p_status) {
case P_SLEEP: // echo output from devtty happens while processes are still sleeping but in-context
nready++; /* We will fix this back up below */
case P_RUNNING: // normal process
break;
default:
panic("psleep: voodoo");
}
if (!event)
udata.u_ptab->p_status = P_PAUSE;
else if (event == (char *) udata.u_ptab)
udata.u_ptab->p_status = P_WAIT;
else
udata.u_ptab->p_status = P_SLEEP;
udata.u_ptab->p_wait = event;
udata.u_ptab->p_waitno = ++waitno;
nready--;
/* It is safe to restore interrupts here. We have already updated the
process state. The worst case is that a wakeup as we switchout
leads us to switch out and back in, or that we wake and run
after other candidates - no different to it occuring after the
switch */
irqrestore(irq);
switchout(); /* Switch us out, and start another process */
/* Switchout doesn't return in this context until we have been switched back in, of course. */
}
void psleep(void *event)
{
irqflags_t irq = di();
#ifdef DEBUG
kprintf("psleep(0x%p)", event);
#endif
switch (udata.u_ptab->p_status) {
case P_SLEEP: // echo output from devtty happens while processes are still sleeping but in-context
case P_STOPPED: // coming to a halt
nready++; /* We will fix this back up below */
case P_RUNNING: // normal process
break;
default:
#ifdef DEBUG
kprintf("psleep(0x%p) -> %d:%d", event, udata.u_ptab->p_pid, udata.u_ptab->p_status);
#endif
panic(PANIC_VOODOO);
}
udata.u_ptab->p_status = P_SLEEP;
udata.u_ptab->p_wait = event;
udata.u_ptab->p_waitno = ++waitno;
nready--;
/* It is safe to restore interrupts here. We have already updated the
process state. The worst case is that a wakeup as we switchout
leads us to switch out and back in, or that we wake and run
after other candidates - no different to it occuring after the
switch */
irqrestore(irq);
switchout(); /* Switch us out, and start another process */
/* Switchout doesn't return in this context until we have been switched back in, of course. */
}
// Fuzix system call handler
// we arrive here from syscall.s with the kernel paged in, using the kernel stack, interrupts enabled.
void unix_syscall(void)
{
// NO LOCAL VARIABLES PLEASE
udata.u_error = 0;
/* Fuzix saves the Stack Pointer and arguments in the
* Assembly Language Function handler in lowlevel.s
*/
if (udata.u_callno >= FUZIX_SYSCALL_COUNT) {
udata.u_error = EINVAL;
} else {
#ifdef DEBUG
kprintf("\t\tpid %d: syscall %d\t%s(%x, %x, %x)\n",
udata.u_ptab->p_pid, udata.u_callno,
syscall_name[udata.u_callno], udata.u_argn,
udata.u_argn1, udata.u_argn2);
#endif
// dispatch system call
udata.u_retval = (*syscall_dispatch[udata.u_callno]) ();
#ifdef DEBUG
kprintf("\t\t\tpid %d: ret syscall %d, ret %x err %d\n",
udata.u_ptab->p_pid, udata.u_callno,
udata.u_retval, udata.u_error);
#endif
}
udata.u_ptab->p_timeout = 0;
chksigs();
di();
if (runticks >= udata.u_ptab->p_priority && nready > 1) {
/* Time to switch out? - we may have overstayed our welcome inside
a syscall so switch straight afterwards */
udata.u_ptab->p_status = P_READY;
switchout();
}
ei();
}
uint8_t chksigs(void)
{
uint8_t j;
uint32_t pending = udata.u_ptab->p_pending & ~udata.u_ptab->p_held;
int (**svec)(int) = &udata.u_sigvec[0];
uint32_t m;
/* Fast path - no signals pending means no work.
Cursig being set means we've already worked out what to do.
*/
rescan:
if (udata.u_cursig || !pending || udata.u_ptab->p_status == P_STOPPED)
return udata.u_cursig;
/* Dispatch the lowest numbered signal */
for (j = 1; j < NSIGS; ++j) {
svec++;
m = sigmask(j);
if (!(m & pending))
continue;
/* This is more complex than in V7 - we have multiple
behaviours plus core dump */
if (*svec == SIG_DFL) {
/* SIGSTOP can't be ignored and puts the process into
P_STOPPED state when it is ready to handle the signal.
Annoyingly right now we have to context switch to the task
in order to stop it in the right place. That would be nice
to fix */
if (m & stopper) {
/* Don't allow us to race SIGCONT */
irqflags_t irq = di();
/* FIXME: can we ever end up here not in READY/RUNNING ? */
nready--;
udata.u_ptab->p_status = P_STOPPED;
udata.u_ptab->p_event = j;
udata.u_ptab->p_pending &= ~m; // unset the bit
irqrestore(irq);
switchout();
/* Other things may have happened */
goto rescan;
}
/* The signal is being handled, so clear it even if
we are exiting (otherwise we'll loop in
chksigs) */
udata.u_ptab->p_pending &= ~m;
if ((m & clear) || udata.u_ptab->p_pid == 1) {
/* SIGCONT is subtle - we woke the process to handle
the signal so ignoring here works fine */
continue;
}
#ifdef DEBUG
kprintf("process terminated by signal %d\n", j);
#endif
/* We may have marked ourselves as asleep and
then been caught by the chksigs when we tried
to task switch into bed. In that case we need
to put the process back in running state */
if (udata.u_ptab->p_status == P_SLEEP) {
udata.u_ptab->p_status = P_RUNNING;
nready++;
}
doexit(dump_core(j));
} else if (*svec != SIG_IGN) {
/* Arrange to call the user routine at return */
udata.u_ptab->p_pending &= ~m; // unset the bit
#ifdef DEBUG
kprintf("about to process signal %d\n", j);
#endif
udata.u_cursig = j;
break;
}
}
return udata.u_cursig;
}
arg_t _sched_yield(void)
{
if (nready > 1)
switchout();
return 0;
}