feat: initial locking etc.

kernel/tasks/task.c

@@ -10,6 +10,7 @@
 #include <mem/pmm.h>
 
 #include <attributes.h>
+#include <libk/libk.h>
 
 #define stack_end(task) ((task)->stack + ((task)->stack_page_count * PAGE_SIZE))
 
@@ -17,7 +18,9 @@
 #define TASK_STATE_RUNNABLE     (1 << 0)
 #define TASK_STATE_RUNNING      (1 << 1)
 #define TASK_STATE_WAIT_IRQ     (1 << 2)
+#define TASK_STATE_WAIT_SIGNAL  (1 << 3)
 
+#define TASK_STATE_STOPPED      (1 << 6)
 #define TASK_STATE_ERROR        (1 << 7)
 
 
@@ -44,7 +47,7 @@ typedef struct {
     char alignment[4];
 } packed task_stack_start;
 
-bool task_locked = false;
+volatile uint32_t task_locked = 0;
 
 task_t *idle_task = NULL;
 task_t *first_task = NULL;
@@ -67,12 +70,45 @@ void cdecl noreturn task_entry_point(task_entrypoint entrypoint, void *entry_dat
     while (true); // halt
 }
 
+void task_ensure_enabled() {
+    if (current_task == NULL) {
+        k_panics("Tasking should be enabled\n");
+    }
+}
+
 void task_lock_acquire() {
-    task_locked = true;
+    if (__sync_add_and_fetch(&task_locked, 1) == UINT32_MAX) {
+        k_panics("To many task locks");
+    };
 }
 
 void task_lock_free() {
-    task_locked = false;
+    if (__sync_sub_and_fetch(&task_locked,  1) == UINT32_MAX) {
+        k_panics("To many task free's");
+    }
+}
+
+uint32_t task_get_current_tid() {
+    return current_task->tid;
+}
+
+void task_signal(uint32_t tid) {
+    task_t *t = first_task;
+    while (t != NULL) {
+        if (t->tid == tid) {
+            if (t->state != TASK_STATE_WAIT_SIGNAL) {
+                // todo
+            }
+            t->state = TASK_STATE_RUNNABLE;
+            break;
+        }
+        t = t->next;
+    }
+}
+
+void task_suspend() {
+    current_task->state = TASK_STATE_WAIT_SIGNAL;
+    task_switch_next();
 }
 
 void noreturn task_idle(void *data) {
@@ -98,7 +134,7 @@ void task_wait_irq(uint16_t irq_bits) {
 }
 
 void task_switch_next_inner(task_t *next_task) {
-    if (task_locked) {
+    if (task_locked != 0) {
         return; // don't switch while the task is locked
     }
     if (next_task == current_task) {
@@ -115,6 +151,9 @@ void task_switch_next_inner(task_t *next_task) {
 }
 
 void task_start_first() {
+    if (task_locked > 0) {
+        k_panics("Tasking locked before start\n");
+    }
     task_switch_next_inner(first_task);
 }
 
@@ -203,5 +242,13 @@ uint32_t task_spawn(task_entrypoint entrypoint, void *entry_data) {
     return new_task->tid;
 }
 
-void task_end(uint32_t pid) {
+void task_end(uint32_t tid) {
+    task_t *t = first_task;
+    while (t != NULL) {
+        if (t->tid == tid) {
+            t->state = TASK_STATE_STOPPED;
+            break;
+        }
+        t = t->next;
+    }
 }