Add function "tasks_switch_to_user"

arch/Makefile

@@ -19,6 +19,7 @@ OBJS += kprintf.c.o
 OBJS += protected.c.o protected.asm.cpp.o
 
 OBJS += tss.c.o tss.asm.cpp.o
+OBJS += tasks.asm.cpp.o
 
 OBJS += interrupt.asm.cpp.o
 

arch/tasks.asm

@@ -0,0 +1,20 @@
+#include "config.h"
+
+[GLOBAL tasks_switch_to_user]
+
+tasks_switch_to_user:
+    mov ebx, [esp+4]
+
+    mov ax, GDT_USER_DS_SELECTOR
+    mov ds, ax
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+
+    mov eax, esp
+    push GDT_USER_DS_SELECTOR
+    push eax
+    pushf
+    push GDT_USER_CS_SELECTOR
+    push ebx
+    iret

arch/tasks.h

@@ -0,0 +1,6 @@
+#ifndef KERNELMQ_INCLUDED_TASKS
+#define KERNELMQ_INCLUDED_TASKS 1
+
+void tasks_switch_to_user(unsigned long addr);
+
+#endif