Minor changes to build system

src/scheduler/sched.c

@@ -39,46 +39,31 @@ void thread_exit(){
     cpu_state *cpu = get_cpu_struct();
     struct thread *p = cpu->current_process;
 
-    kprintf("hi");
-
-    // Remove process from circular linked list
-    p->prev->next = p->next;
-
     if(p == p->next){
-        cpu->current_process = idle;
-    }
+        // If this is the only thread in the queue then set cpu->head to NULL, so scheduler knows to idle
+        cpu->head = NULL;
+    }else{
+        // Remove process from circular linked list
+        p->next->prev = p->prev;
+        p->prev->next = p->next;
 
-    if(p == cpu->head){
+        if(p == cpu->head){
+            //cpu->head = p->next;
+        }
 
     }
 
-    ma_cache_dealloc(p); // KILL the thread
+    p->state = ZOMBIE;
 
-    sched();
+    // Switch to scheduler
+    yield();
 }
 
 /* Setup a process structure */
 struct thread *alloc_thread(void){
-    struct cpu_state *cpu = get_cpu_struct();
-    struct thread *head = get_cpu_struct()->head;
-    struct thread *base = get_cpu_struct()->base;
-
     struct thread *t = ma_cache_alloc(thread_cache, 0);
     memset(t, 0, sizeof(struct thread));
 
-    if(base == NULL){
-        t->next = t;
-        t->prev = t;
-        cpu->base = t;
-        cpu->head = t;
-    } else {
-        t->prev = head;
-        t->next = base;
-        head->next = t;
-        base->prev = t;
-        cpu->head = t;
-    }
-
     t->state = READY;
 
     t->kstack = kzalloc(8 * 4096);
@@ -100,36 +85,61 @@ struct thread *alloc_thread(void){
 
 }
 
-struct thread *add_process(uint64_t *entry){
-    struct thread *proc = alloc_thread();
+struct thread *add_thread(uint64_t *entry){
+    struct thread *t = alloc_thread();
 
-    if (proc == NULL) {
-        klog(__func__, "proc == null!");
-        kkill();
+    assert(t != NULL && "Thread allocation failed!");
+
+    struct cpu_state *cpu = get_cpu_struct();
+    struct thread *head = get_cpu_struct()->head;
+    struct thread *base = get_cpu_struct()->base;    
+
+    // Manage circley linked list
+    if(base == NULL){
+        t->next = t;
+        t->prev = t;
+        cpu->base = t;
+        cpu->head = t;
+    } else {
+        t->prev = head;
+        t->next = base;
+        head->next = t;
+        base->prev = t;
+        cpu->head = t;
     }
 
-    proc->context->rip = (uint64_t)entry;
+    t->context->rip = (uint64_t)entry;
 
-    //kprintf("entry: 0x{xn}", entry);
-
-    return proc;
+    return t;
 }
 
 
 [[noreturn]] void sched(){
-    cpu_state *cpu = get_cpu_struct();
+    for(;;){
+        asm("cli"); // we sti at the end of switch_context
+        cpu_state *cpu = get_cpu_struct();
+        struct thread *prev = cpu->current_process;
 
-    asm("cli");
+        if(prev->state == ZOMBIE){
+            kprintf("we are freeing allocated thread 0x{x}\n", prev);
+            ma_cache_dealloc(prev);
+        }else{
+            prev->state = READY;
+        }
 
-    struct thread *prev = cpu->current_process;
-    prev->state = READY;
-    
-    cpu->current_process = prev->next;
-    
-    cpu->current_process->state = RUNNING;
-    asm("sti");
-    switch_context(&(get_cpu_struct()->scheduler_context), get_cpu_struct()->current_process->context);
-    
+        if(cpu->head == NULL){
+            cpu->current_process = idle;
+        }else{
+            if(prev->next){
+                cpu->current_process = prev->next;
+            }else{
+                cpu->current_process = cpu->head;
+            }
+        }
+        
+        cpu->current_process->state = RUNNING;
+        switch_context(&(get_cpu_struct()->scheduler_context), get_cpu_struct()->current_process->context);
+    }
 }
 
 void scheduler_init(){
@@ -142,11 +152,11 @@ void scheduler_init(){
         return;
     }
 
-    idle = add_process((uint64_t*)idle_task);
+    idle = alloc_thread();
+    idle->context->rip = (uint64_t)idle;
 
     assert(idle != NULL && "Failed to allocate idle task!");
 
-    
     cpu->current_process = idle;
 
     cpu->scheduler_stack = kzalloc(4096);
@@ -154,9 +164,9 @@ void scheduler_init(){
     cpu->scheduler_context->rbp = (uint64_t)cpu->scheduler_context;
     cpu->scheduler_context->rip = (uint64_t)sched;
     
-    add_process((uint64_t*)test_task);
+    add_thread((uint64_t*)test_task);
 
-    add_process((uint64_t *)best_task);
+    add_thread((uint64_t *)best_task);
 
     // Initialize scheduler -> we will now get timer interrupts to switch us into sched()
     cpu->scheduler_initialized = true;