Initial commit: SUB-OS 64-Bit Production Monolithic Operating System with LazyBox userland suite

kernel/task.c

@@ -0,0 +1,81 @@
+#include <kernel/task.h>
+#include <kernel/sched.h>
+#include <mm/kmalloc.h>
+#include <lib/string.h>
+
+static pid_t next_pid = 1;
+static task_t* current_task = NULL;
+static task_t kernel_idle_task;
+
+static void task_wrapper(task_entry_fn_t entry, void* arg) {
+    if (entry) {
+        entry(arg);
+    }
+    task_exit(0);
+}
+
+task_t* task_create(const char* name, task_entry_fn_t entry, void* arg, int priority) {
+    task_t* task = (task_t*)kzalloc(sizeof(task_t));
+    if (!task) return NULL;
+
+    task->pid = next_pid++;
+    strncpy(task->name, name ? name : "task", sizeof(task->name) - 1);
+    task->state = TASK_STATE_READY;
+    task->priority = priority;
+    task->time_slice = 10; // 10 ticks = 100ms default
+
+    // Allocate 16 KB stack for thread
+    task->stack_size = 16384;
+    task->stack_base = (uint64_t)kmalloc(task->stack_size);
+    if (!task->stack_base) {
+        kfree(task);
+        return NULL;
+    }
+
+    uint64_t* stack_top = (uint64_t*)(task->stack_base + task->stack_size);
+
+    // Set up initial stack frame for AMD64
+    *(--stack_top) = (uint64_t)arg;          // RDI (arg)
+    *(--stack_top) = (uint64_t)entry;        // RSI (entry function)
+    *(--stack_top) = (uint64_t)task_wrapper; // RIP
+
+    task->rsp = (uint64_t)stack_top;
+
+    INIT_LIST_HEAD(&task->list);
+    sched_add_task(task);
+
+    return task;
+}
+
+void task_exit(int exit_code) {
+    (void)exit_code;
+    if (current_task && current_task->pid != 0) {
+        current_task->state = TASK_STATE_DEAD;
+        sched_remove_task(current_task);
+        sched_yield();
+    }
+    while (1) {
+        __asm__ volatile("hlt");
+    }
+}
+
+task_t* task_current(void) {
+    return current_task;
+}
+
+pid_t task_get_pid(void) {
+    return current_task ? current_task->pid : 0;
+}
+
+void task_set_current(task_t* task) {
+    current_task = task;
+}
+
+void task_init_idle(void) {
+    memset(&kernel_idle_task, 0, sizeof(task_t));
+    kernel_idle_task.pid = 0;
+    strcpy(kernel_idle_task.name, "swapper/0");
+    kernel_idle_task.state = TASK_STATE_RUNNING;
+    INIT_LIST_HEAD(&kernel_idle_task.list);
+    current_task = &kernel_idle_task;
+}