feat(lab02): add ex06

doc/lab-01_02.typ

@@ -369,6 +369,8 @@ registers[0] = ioremap(CHIP_ID_BASE_ADDR, 0x1000);
   ]
 )
 
+Easy exercice, a thread in the kernet is a `struct task_struct*` that can be created with `kthread_run`
+
 //-------------------
 // Exercise 7: Sleeping
 //-------------------

src/01-skeleton/s02e04-dynamic_allocation.c

@@ -49,7 +49,9 @@ void dynAlloc_exit(void) {
         e = list_entry(list_unique_elements.next, struct element, node);
         pr_info ("delete element %d: %s\n", e->unique_number, e->text);
         list_del(&e->node);
-        kfree(e);
+        if (e != 0) {
+            kfree(e);
+        }
     }
 
     pr_info("Memory allocated for dynamic allocation and linked list freed\n");

src/01-skeleton/s02e06-thread.c

@@ -0,0 +1,42 @@
+#include <linux/module.h>	// needed by all modules
+#include <linux/init.h>		// needed for macros
+#include <linux/kernel.h>	// needed for debugging
+
+
+#include <linux/kthread.h>
+#include <linux/delay.h>
+
+static struct task_struct* sample_thread;
+
+#define DELAY_S 5
+
+int thread_skeletonThread (void* data) {
+
+    pr_info("Thread started\n");
+
+    while (!kthread_should_stop()) {
+        pr_info("PING!\n");
+        ssleep(DELAY_S);
+    }
+
+    return 0;
+}
+
+void thread_init(void) {
+    pr_info("Initialize kernel thread\n");
+
+    sample_thread = kthread_run(thread_skeletonThread, NULL, "The Machine that goes");
+    if (IS_ERR(sample_thread)) {
+        pr_err("Failed to create kernel thread\n");
+        return;
+    }
+
+    pr_info("Kernel thread initialized\n");
+
+}
+
+void thread_exit(void) {
+    pr_info("Exiting kernel thread\n");
+    kthread_stop(sample_thread);
+    pr_info("Kernel thread exited\n");
+}

src/01-skeleton/skeleton.c

@@ -6,6 +6,7 @@
 #include "s02e02-parameters.c"
 #include "s02e04-dynamic_allocation.c"
 #include "s02e05-io_memory_mapped.c"
+#include "s02e06-thread.c"
 
 
 static int __init skeleton_init(void) {
@@ -27,6 +28,11 @@ static int __init skeleton_init(void) {
 
     pr_info("--------------------\n");
 
+    // Lab02 - Exercise 6: Kernel thread
+    thread_init();
+
+    pr_info("--------------------\n");
+
     pr_info("Linux module skeleton loaded\n");
 	return 0;
 }
@@ -44,6 +50,11 @@ static void __exit skeleton_exit(void) {
 
     pr_info("--------------------\n");
 
+    // Lab02 - Exercise 6: Kernel thread
+    thread_exit();
+
+    pr_info("--------------------\n");
+
     pr_info ("Linux module skeleton unloaded\n");
 }