kthread.c

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#include <core/system.h>
#include <core/arch.h>
#include <core/panic.h>
#include <core/string.h>
#include <mm/vm.h>
#include <sys/kthread.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <ds/queue.h>
 
MALLOC_DECLARE(M_PROC);
 
struct proc *kproc;

static int kproc_init(void)
{
    struct proc *proc = kmalloc(sizeof(struct proc), &M_PROC, M_ZERO);
 
    if (!proc)
        return -ENOMEM;
 
    proc->pid  = 0;     /* never allocated: init is 1 */
    proc->name = strdup("[kernel]");
 
    if (!proc->name)
        panic("no memory for process 0");
    proc->vm_space.pmap = kvm_space.pmap;
    proc->running = 1;
 
    for (int i = 0; i < SIG_MAX; ++i)
        proc->sigaction[i].sa_handler = SIG_DFL;
 
    /* the kernel can't boot without process 0 */
    if (!proc->name || session_new(proc) || !enqueue(procs, proc))
        panic("kthread: can't make process 0");
 
    kproc = proc;
 
    return 0;
}

static void kthread_start(void)
{
    curthread->kentry(curthread->karg);
    panic("a kernel thread returned");
}

int kthread_create(const char *name, void (*fn)(void *), void *arg, struct thread **ref)
{
    int err;
    struct thread *thread = NULL;
 
    if (!kproc && (err = kproc_init()))
        return err;
 
    if ((err = thread_new(kproc, &thread)))
        return err;
 
    thread->name   = name;
    thread->kentry = fn;
    thread->karg   = arg;
 
    arch_kthread_create(thread, (uintptr_t) kthread_start);
 
    if (!thread->arch) {
        queue_remove(&kproc->threads, thread);
        kfree(thread);
        return -ENOMEM;
    }
 
    /* the scheduler switches to it as to any thread that was switched
     * away from: its saved context is its start */
    thread->spawned = 1;
    thread->state = RUNNABLE;
    sched_thread_ready(thread);
 
    if (ref)
        *ref = thread;
 
    return 0;
}