kthread: implement exit

core/irq_pit.S

@@ -2,7 +2,7 @@
 
 .text
 
-.extern selectNextThread
+.extern switchKthread
 
 .globl pit_handler
 .type pit_handler, @function
@@ -21,7 +21,7 @@ pit_handler:         // already got eflags, cs and eip on stack thanks to CPU
   outb  %al, $0x20
 
   pushl %esp
-  call selectNextThread
+  call switchKthread
   movl %eax,%esp
 
   /* Restore the CPU context */

core/kthread.c

@@ -1,12 +1,19 @@
+#include "assert.h"
 #include "kthread.h"
 #include "list.h"
 #include "alloc.h"
 #include "klibc.h"
+#include "vga.h"
 
 static struct kthread *currentThread;
 
-void _kthread_exit(){
-        //TODO 
+void kthread_exit(){
+        struct kthread *current = currentThread;
+        struct kthread *next =  selectNextKthread();
+        if (next == current)
+                assert("cannot exit thread");
+        currentThread = next;
+        cpu_context_exit_to(next->cpuState, (cpu_kstate_function_arg1_t *)deleteKthread, (uint32_t)current);
         return;
 }
 
@@ -41,7 +48,7 @@ struct kthread *createKthread(const char *name, cpu_kstate_function_arg1_t func,
 
         if(cpu_kstate_init(&thread->cpuState, (cpu_kstate_function_arg1_t *)func, (vaddr_t)args,
                     thread->stackAddr, thread->stackSize,
-                    (cpu_kstate_function_arg1_t *)_kthread_exit, 0))
+                    (cpu_kstate_function_arg1_t *)kthread_exit, 0))
                 goto free_mem;
 
         list_add_tail(currentThread, thread);
@@ -59,9 +66,15 @@ void deleteKthread(struct kthread *thread){
         free((void *)thread);
 }
 
-struct cpu_state *selectNextThread(struct cpu_state *prevCpu){
-        currentThread->cpuState = prevCpu;
+struct kthread *selectNextKthread(){
         struct kthread *nextThread = currentThread->next;
+        return nextThread;
+}
+
+struct cpu_state *switchKthread(struct cpu_state *prevCpu){
+        currentThread->cpuState = prevCpu;
+        struct kthread *nextThread = selectNextKthread();
+        printStringDetails(nextThread->name, RED, BLACK, 40, VGA_HEIGHT - 1);
         currentThread = nextThread;
         return nextThread->cpuState;
 }

core/kthread.h

@@ -17,10 +17,12 @@ struct kthread {
 
 
 int kthreadSetup(vaddr_t mainStack, size_t mainStackSize);
+void kthread_exit();
 
 struct kthread *createKthread(const char *name, cpu_kstate_function_arg1_t func,
 			      void *args);
 
 void deleteKthread(struct kthread *thread);
 
-struct cpu_state *selectNextThread(struct cpu_state *prev_cpu);
+struct kthread *selectNextKthread();
+struct cpu_state *switchKthread(struct cpu_state *prevCpu);

core/main.c

@@ -28,15 +28,11 @@ void cpuid(int code, uint32_t *a, uint32_t *d)
 
 void idleThread(void *arg){
     (void)arg;
+    int count = 0;
     while(1)
-        printf(".");
+        printIntDetails(count++, GREEN, BLACK, 0, VGA_HEIGHT - 1);
 }
 
-void dashThread(void *arg){
-    (void)arg;
-    while(1)
-        printf("-");
-}
 
 // Multiboot information available here :
 // https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#kernel_002ec
@@ -124,15 +120,13 @@ void kmain(unsigned long magic, unsigned long addr)
     allocInit();
     kthreadSetup(_stack_bottom, (_stack_top - _stack_bottom + 1));
     createKthread("idle", idleThread, NULL);
-    createKthread("dash", dashThread, NULL);
     irqSetRoutine(IRQ_TIMER, pit_handler);
 #ifdef RUN_TEST
     run_test();
 #endif
+    printf("\nSystem init done\n");
 
-    int count = 0;
-    while (1) {
-        printIntDetails(count++, GREEN, BLACK, 0, VGA_HEIGHT - 1);
-    }
-    printf("exiting\n");
+    // There is no real caller behind this point
+    // So finish this by ourself
+    kthread_exit();
 }