From c63f340d90800895f007de64b7d2d14624263331 Mon Sep 17 00:00:00 2001
From: nthnluu <nate1299@me.com>
Date: Sun, 28 Jan 2024 21:20:27 -0500
Subject: Created student weenix repository

---
 kernel/proc/kthread.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 kernel/proc/kthread.c

(limited to 'kernel/proc/kthread.c')

diff --git a/kernel/proc/kthread.c b/kernel/proc/kthread.c
new file mode 100644
index 0000000..f1c541c
--- /dev/null
+++ b/kernel/proc/kthread.c
@@ -0,0 +1,136 @@
+// SMP.1 for non-curthr actions; none for curthr
+#include "config.h"
+#include "globals.h"
+#include "mm/slab.h"
+#include "util/debug.h"
+#include "util/string.h"
+
+/*==========
+ * Variables
+ *=========*/
+
+/*
+ * Global variable maintaining the current thread on the cpu
+ */
+kthread_t *curthr CORE_SPECIFIC_DATA;
+
+/*
+ * Private slab for kthread structs
+ */
+static slab_allocator_t *kthread_allocator = NULL;
+
+/*=================
+ * Helper functions
+ *================*/
+
+/*
+ * Allocates a new kernel stack. Returns null when not enough memory.
+ */
+static char *alloc_stack() { return page_alloc_n(DEFAULT_STACK_SIZE_PAGES); }
+
+/*
+ * Frees an existing kernel stack.
+ */
+static void free_stack(char *stack)
+{
+    page_free_n(stack, DEFAULT_STACK_SIZE_PAGES);
+}
+
+/*==========
+ * Functions
+ *=========*/
+
+/*
+ * Initializes the kthread_allocator.
+ */
+void kthread_init()
+{
+    KASSERT(__builtin_popcount(DEFAULT_STACK_SIZE_PAGES) == 1 &&
+            "stack size should be a power of 2 pages to reduce fragmentation");
+    kthread_allocator = slab_allocator_create("kthread", sizeof(kthread_t));
+    KASSERT(kthread_allocator);
+}
+
+/*
+ * Creates and initializes a thread.
+ * Returns a new kthread, or NULL on failure.
+ *
+ * Hints:
+ * Use kthread_allocator to allocate a kthread
+ * Use alloc_stack() to allocate a kernel stack
+ * Use context_setup() to set up the thread's context - 
+ *  also use DEFAULT_STACK_SIZE and the process's pagetable (p_pml4)
+ * Remember to initialize all the thread's fields
+ * Remember to add the thread to proc's threads list
+ * Initialize the thread's kt_state to KT_NO_STATE
+ * Initialize the thread's kt_recent_core to ~0UL (unsigned -1)
+ */
+kthread_t *kthread_create(proc_t *proc, kthread_func_t func, long arg1,
+                          void *arg2)
+{
+    NOT_YET_IMPLEMENTED("PROCS: ***none***");
+    return NULL;
+}
+
+/*
+ * Creates and initializes a thread that is a clone of thr.
+ * Returns a new kthread, or null on failure.
+ * 
+ * P.S. Note that you do not need to implement this function until VM.
+ *
+ * Hints:
+ * The only parts of the context that must be initialized are c_kstack and
+ * c_kstacksz. The thread's process should be set outside of this function. Copy
+ * over thr's retval, errno, and cancelled; other fields should be freshly
+ * initialized. See kthread_create() for more hints.
+ */
+kthread_t *kthread_clone(kthread_t *thr)
+{
+    NOT_YET_IMPLEMENTED("VM: ***none***");
+    return NULL;
+}
+
+/*
+ * Free the thread's stack, remove it from its process's list of threads, and
+ * free the kthread_t struct itself. Protect access to the kthread using its
+ * kt_lock.
+ *
+ * You cannot destroy curthr.
+ */
+void kthread_destroy(kthread_t *thr)
+{
+    KASSERT(thr != curthr);
+    KASSERT(thr && thr->kt_kstack);
+    if (thr->kt_state != KT_EXITED)
+        panic("destroying thread in state %d\n", thr->kt_state);
+    free_stack(thr->kt_kstack);
+    if (list_link_is_linked(&thr->kt_plink))
+        list_remove(&thr->kt_plink);
+
+    slab_obj_free(kthread_allocator, thr);
+}
+
+/*
+ * Sets the thread's return value and cancels the thread.
+ *
+ * Note: Check out the use of check_curthr_cancelled() in syscall_handler()
+ * to see how a thread eventually notices it is cancelled and handles exiting
+ * itself.
+ *
+ * Hints:
+ * This should not be called on curthr.
+ * Use sched_cancel() to actually mark the thread as cancelled. This way you
+ * can take care of all cancellation cases. 
+ */
+void kthread_cancel(kthread_t *thr, void *retval)
+{
+    NOT_YET_IMPLEMENTED("PROCS: ***none***");
+}
+
+/*
+ * Wrapper around proc_thread_exiting().
+ */
+void kthread_exit(void *retval)
+{
+    NOT_YET_IMPLEMENTED("PROCS: ***none***");
+}
-- 
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