write kernel sp to tss in dispatcher

kernel/arch/core_ring.cc

@@ -17,6 +17,10 @@ void switchToUsermode(void *stackpointer, void *kickoff,
     constexpr uint16_t user_ds = 4 << 3 | 3;
 
     asm volatile ( \
+            "mov %[user_data], %%ds \n" \
+            "mov %[user_data], %%es \n" \
+            "mov %[user_data], %%fs \n" \
+            "mov %[user_data], %%gs \n" \
             "pushq %[user_data] \n" \
             "pushq %[user_stack] \n" \
             "pushq %[user_eflags] \n" \

kernel/arch/gdt.cc

@@ -3,8 +3,6 @@
 #include "core.h"
 #include "tss.h"
 
-TSS::Entry mytss;
-
 namespace GDT {
 
 // The static 32-bit Global Descriptor Table (GDT)

kernel/arch/tss.h

@@ -47,3 +47,5 @@ void init();
 void setStackpointer(void* ptr);
 
 }  // namespace TSS
+extern TSS::Entry mytss;
+