feat: added reaper and suicide support

kernel/tasks/task.c

@@ -10,6 +10,7 @@
 #include <myke/cpu/cpu.h>
 #include <myke/libk/libk.h>
 #include <myke/mem/pmm.h>
+#include <myke/libk/syscall.h>
 #include <myke/tasks/task.h>
 
 #define stack_end(task) ((task)->stack + ((task)->stack_page_count * PAGE_SIZE))
@@ -30,7 +31,7 @@ typedef struct task {
     uint8_t state;
     uint16_t wait_irq;
 
-    uint32_t tid;
+    pid_t tid;
 
     int errno;
 
@@ -57,19 +58,23 @@ task_t *first_task = NULL;
 task_t *last_task = NULL;
 task_t *current_task = NULL;
 
-uint32_t last_tid = 0;
+pid_t last_tid = 0;
 
-extern switch_task(task_registers_t
-**, task_registers_t*);
+pid_t reaper_pid = 0;
+
+extern void switch_task(task_registers_t **, task_registers_t *);
 
 extern att_cdecl att_noreturn void __task_entry_point();
 
 extern att_noreturn void __task_entry_point_inner();
 
+// internal api
+void task_free(task_t* task);
+
 // explicit cdecl calling convention
-void att_cdecl att_noreturn task_entry_point(task_entrypoint entrypoint, void *entry_data) {
+void att_unused att_cdecl att_noreturn task_entry_point(task_entrypoint entrypoint, void *entry_data) {
     entrypoint(entry_data);
-//    task_end_self();
+    syscall_kill_self();
     while (true); // halt
 }
 
@@ -91,7 +96,7 @@ void task_lock_free() {
     }
 }
 
-uint32_t task_get_current_tid() {
+pid_t task_get_current_tid() {
     return current_task->tid;
 }
 
@@ -114,10 +119,47 @@ void task_suspend() {
     task_switch_next();
 }
 
+// internal tasks
 void att_noreturn task_idle(void *data) {
     while (true) __asm__("hlt");
 }
 
+void att_noreturn task_reaper(void *data) {
+    while (true) {
+        bool did_reap = false;
+        task_lock_acquire();
+        task_t *t = first_task;
+        task_t *p = first_task;
+        task_t *n = NULL;
+        while (t != NULL) {
+            n = t->next;
+            if (t->state == TASK_STATE_STOPPED) {
+                did_reap = true;
+                if (t == first_task) {
+                    if (n == NULL) {
+                        k_panics("No more tasks");
+                    }
+                    first_task = n;
+                    task_free(t);
+                    t = NULL;
+                } else {
+                    p->next = n;
+                    task_free(t);
+                    t = p;
+                }
+            }
+            p = t;
+            t = n;
+        }
+        task_lock_free();
+        if (did_reap) {
+            syscall_yield_job();
+        } else {
+            syscall_job_suspend();
+        }
+    }
+}
+
 void task_notify_irq(uint8_t irq_no) {
     uint16_t irq__bit = 1 << irq_no;
     task_t *t = first_task;
@@ -233,11 +275,17 @@ task_t *task_create(task_entrypoint entrypoint, void *entry_data) {
 
 }
 
-void task_init() {
-    idle_task = task_create(task_idle, NULL);
+void task_free(task_t *task) {
+    pmm_free_pages(task->stack, 16);
+    free(task);
 }
 
-uint32_t task_spawn(task_entrypoint entrypoint, void *entry_data) {
+void task_init() {
+    idle_task = task_create(task_idle, NULL);
+    reaper_pid = task_spawn(task_reaper, NULL);
+}
+
+pid_t task_spawn(task_entrypoint entrypoint, void *entry_data) {
     task_t *new_task = task_create(entrypoint, entry_data);
     if (first_task == NULL) {
         // first task
@@ -249,11 +297,12 @@ uint32_t task_spawn(task_entrypoint entrypoint, void *entry_data) {
     return new_task->tid;
 }
 
-void task_end(uint32_t tid) {
+void task_end(pid_t tid) {
     task_t *t = first_task;
     while (t != NULL) {
         if (t->tid == tid) {
             t->state = TASK_STATE_STOPPED;
+            task_signal(reaper_pid);
             break;
         }
         t = t->next;