void new_thread_handler(int sig)
{
int (*fn)(void *), n;
void *arg;
fn = current->thread.request.u.thread.proc;
arg = current->thread.request.u.thread.arg;
change_sig(SIGUSR1, 1);
thread_wait(¤t->thread.mode.skas.switch_buf,
current->thread.mode.skas.fork_buf);
if(current->thread.prev_sched != NULL)
schedule_tail(current->thread.prev_sched);
current->thread.prev_sched = NULL;
/* The return value is 1 if the kernel thread execs a process,
* 0 if it just exits
*/
n = run_kernel_thread(fn, arg, ¤t->thread.exec_buf);
if(n == 1){
/* Handle any immediate reschedules or signals */
interrupt_end();
userspace(¤t->thread.regs.regs);
}
else do_exit(0);
}
void kernel_thread_start(struct task_struct *p)
{
struct pt_regs *r = ¤t->thread.regs;
int (*func)(void *) = (void *)r->si;
schedule_tail(p);
do_exit(func((void *)r->di));
}
static void continue_new_vcpu(struct vcpu *prev)
{
schedule_tail(prev);
if ( is_idle_vcpu(current) )
reset_stack_and_jump(idle_loop);
else if ( is_32bit_domain(current->domain) )
/* check_wakeup_from_wait(); */
reset_stack_and_jump(return_to_new_vcpu32);
else
/* check_wakeup_from_wait(); */
reset_stack_and_jump(return_to_new_vcpu64);
}
void fork_handler(int sig)
{
change_sig(SIGUSR1, 1);
thread_wait(¤t->thread.mode.skas.switch_buf,
current->thread.mode.skas.fork_buf);
force_flush_all();
if(current->thread.prev_sched == NULL)
panic("blech");
schedule_tail(current->thread.prev_sched);
current->thread.prev_sched = NULL;
userspace(¤t->thread.regs.regs);
}
void context_switch(struct vcpu *prev, struct vcpu *next)
{
ASSERT(local_irq_is_enabled());
ASSERT(prev != next);
ASSERT(cpumask_empty(next->vcpu_dirty_cpumask));
if ( prev != next )
update_runstate_area(prev);
local_irq_disable();
set_current(next);
prev = __context_switch(prev, next);
schedule_tail(prev);
}
void fork_handler(int sig)
{
change_sig(SIGUSR1, 1);
thread_wait(¤t->thread.mode.skas.switch_buf,
current->thread.mode.skas.fork_buf);
force_flush_all();
if(current->thread.prev_sched == NULL)
panic("blech");
schedule_tail(current->thread.prev_sched);
current->thread.prev_sched = NULL;
/* Handle any immediate reschedules or signals */
interrupt_end();
userspace(¤t->thread.regs.regs);
}
/* Called magically, see new_thread_handler above */
void fork_handler(void)
{
force_flush_all();
if(current->thread.prev_sched == NULL)
panic("blech");
schedule_tail(current->thread.prev_sched);
/* XXX: if interrupt_end() calls schedule, this call to
* arch_switch_to_skas isn't needed. We could want to apply this to
* improve performance. -bb */
arch_switch_to_skas(current->thread.prev_sched, current);
current->thread.prev_sched = NULL;
/* Handle any immediate reschedules or signals */
interrupt_end();
userspace(¤t->thread.regs.regs);
}
static void new_thread_handler(int sig)
{
unsigned long disable;
int (*fn)(void *);
void *arg;
fn = current->thread.request.u.thread.proc;
arg = current->thread.request.u.thread.arg;
UPT_SC(¤t->thread.regs.regs) = (void *) (&sig + 1);
disable = (1 << (SIGVTALRM - 1)) | (1 << (SIGALRM - 1)) |
(1 << (SIGIO - 1)) | (1 << (SIGPROF - 1));
SC_SIGMASK(UPT_SC(¤t->thread.regs.regs)) &= ~disable;
suspend_new_thread(current->thread.mode.tt.switch_pipe[0]);
force_flush_all();
if(current->thread.prev_sched != NULL)
schedule_tail(current->thread.prev_sched);
current->thread.prev_sched = NULL;
init_new_thread_signals(1);
enable_timer();
free_page(current->thread.temp_stack);
set_cmdline("(kernel thread)");
change_sig(SIGUSR1, 1);
change_sig(SIGVTALRM, 1);
change_sig(SIGPROF, 1);
local_irq_enable();
if(!run_kernel_thread(fn, arg, ¤t->thread.exec_buf))
do_exit(0);
/* XXX No set_user_mode here because a newly execed process will
* immediately segfault on its non-existent IP, coming straight back
* to the signal handler, which will call set_user_mode on its way
* out. This should probably change since it's confusing.
*/
}
void finish_fork_handler(int sig)
{
UPT_SC(¤t->thread.regs.regs) = (void *) (&sig + 1);
suspend_new_thread(current->thread.mode.tt.switch_pipe[0]);
force_flush_all();
if(current->thread.prev_sched != NULL)
schedule_tail(current->thread.prev_sched);
current->thread.prev_sched = NULL;
enable_timer();
change_sig(SIGVTALRM, 1);
local_irq_enable();
if(current->mm != current->parent->mm)
protect_memory(uml_reserved, high_physmem - uml_reserved, 1,
1, 0, 1);
task_protections((unsigned long) current_thread);
free_page(current->thread.temp_stack);
local_irq_disable();
change_sig(SIGUSR1, 0);
set_user_mode(current);
}
struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *next)
{
struct thread_info *_prev = task_thread_info(prev);
struct thread_info *_next = task_thread_info(next);
/*
* schedule() expects the return of this function to be the task that we
* switched away from. Returning prev is not going to work because we
* are actually going to return the previous taks that was scheduled
* before the task we are going to wake up, and not the current task,
* e.g.:
*
* swapper -> init: saved prev on swapper stack is swapper
* init -> ksoftirqd0: saved prev on init stack is init
* ksoftirqd0 -> swapper: returned prev is swapper
*/
static struct task_struct *abs_prev = &init_task;
/*
* We need to free the thread_info structure in free_thread_info to
* avoid races between the dying thread and other threads. We also need
* to cleanup sched_sem and signal to the prev thread that it needs to
* exit, and we use this stack varible to pass this info.
*/
struct thread_exit_info ei = {
.dead = false,
.sched_sem = _prev->sched_sem,
};
_current_thread_info = task_thread_info(next);
_next->prev_sched = prev;
abs_prev = prev;
_prev->exit_info = &ei;
lkl_ops->sem_up(_next->sched_sem);
/* _next may be already gone so use ei instead */
lkl_ops->sem_down(ei.sched_sem);
if (ei.dead) {
lkl_ops->sem_free(ei.sched_sem);
threads_counter_dec();
lkl_ops->thread_exit();
}
_prev->exit_info = NULL;
return abs_prev;
}
struct thread_bootstrap_arg {
struct thread_info *ti;
int (*f)(void *);
void *arg;
};
static void thread_bootstrap(void *_tba)
{
struct thread_bootstrap_arg *tba = (struct thread_bootstrap_arg *)_tba;
struct thread_info *ti = tba->ti;
int (*f)(void *) = tba->f;
void *arg = tba->arg;
lkl_ops->sem_down(ti->sched_sem);
kfree(tba);
if (ti->prev_sched)
schedule_tail(ti->prev_sched);
f(arg);
do_exit(0);
}
int copy_thread(unsigned long clone_flags, unsigned long esp,
unsigned long unused, struct task_struct *p)
{
struct thread_info *ti = task_thread_info(p);
struct thread_bootstrap_arg *tba;
int ret;
tba = kmalloc(sizeof(*tba), GFP_KERNEL);
if (!tba)
return -ENOMEM;
tba->f = (int (*)(void *))esp;
tba->arg = (void *)unused;
tba->ti = ti;
ret = lkl_ops->thread_create(thread_bootstrap, tba);
if (ret) {
kfree(tba);
return -ENOMEM;
}
threads_counter_inc();
return 0;
}
void show_stack(struct task_struct *task, unsigned long *esp)
{
}
static inline void pr_early(const char *str)
{
if (lkl_ops->print)
lkl_ops->print(str, strlen(str));
}
/**
* This is called before the kernel initializes, so no kernel calls (including
* printk) can't be made yet.
*/
int threads_init(void)
{
struct thread_info *ti = &init_thread_union.thread_info;
int ret = 0;
ti->exit_info = NULL;
ti->prev_sched = NULL;
ti->sched_sem = lkl_ops->sem_alloc(0);
if (!ti->sched_sem) {
pr_early("lkl: failed to allocate init schedule semaphore\n");
ret = -ENOMEM;
goto out;
}
threads_counter_lock = lkl_ops->sem_alloc(1);
if (!threads_counter_lock) {
pr_early("lkl: failed to alllocate threads counter lock\n");
ret = -ENOMEM;
goto out_free_init_sched_sem;
}
return 0;
out_free_init_sched_sem:
lkl_ops->sem_free(ti->sched_sem);
out:
return ret;
}
void threads_cleanup(void)
{
struct task_struct *p;
for_each_process(p) {
struct thread_info *ti = task_thread_info(p);
if (p->pid != 1)
WARN(!(p->flags & PF_KTHREAD),
"non kernel thread task %p\n", p->comm);
WARN(p->state == TASK_RUNNING,
"thread %s still running while halting\n", p->comm);
kill_thread(ti->exit_info);
}
while (threads_counter_get())
;
lkl_ops->sem_free(init_thread_union.thread_info.sched_sem);
lkl_ops->sem_free(threads_counter_lock);
}
