diff --git a/arch/x86/segment.c b/arch/x86/segment.c
index 24ae3afc..4cad0566 100644
--- a/arch/x86/segment.c
+++ b/arch/x86/segment.c
@@ -56,6 +56,23 @@ idt_ptr_t boot_idt_ptr __data_init = {
     .addr = _ul(&boot_idt),
 };
 
+
+gdt_desc_t __data_rmode rmode_gdt[NR_RMODE_GDT_ENTRIES] __aligned(16) = {
+    /* clang-format off */
+    [GDT_NULL].desc      = GDT_ENTRY(0x0, 0x0, 0x0),
+    [GDT_KERN_CS32].desc = GDT_ENTRY(DESC_FLAGS(GR, SZ, P, DPL0, S, CODE, R, A), 0x0, 0xfffff),
+    [GDT_KERN_DS32].desc = GDT_ENTRY(DESC_FLAGS(GR, SZ, P, DPL0, S, DATA, W, A), 0x0, 0xfffff),
+    [GDT_KERN_CS64].desc = GDT_ENTRY(DESC_FLAGS(GR,  L, P, DPL0, S, CODE, R, A), 0x0, 0x00000),
+    [GDT_RMODE_CS16].desc = GDT_ENTRY(DESC_FLAGS(P, DPL0, S, CODE, R, A), 0x0, 0xfffff),
+    [GDT_RMODE_DS16].desc = GDT_ENTRY(DESC_FLAGS(P, DPL0, S, DATA, W, A), 0x0, 0xfffff),
+    /* clang-format on */
+};
+
+gdt_ptr_t __data_rmode rmode_gdt_ptr = {
+    .size = sizeof(rmode_gdt) - 1,
+    .addr = _ul(&rmode_gdt),
+};
+
 static void __text_init init_boot_tss(void) {
 #if defined(__i386__)
     boot_tss_df.iopb = sizeof(boot_tss_df);
diff --git a/include/arch/x86/segment.h b/include/arch/x86/segment.h
index 6afca0b9..c1e51dea 100644
--- a/include/arch/x86/segment.h
+++ b/include/arch/x86/segment.h
@@ -34,6 +34,9 @@
 #define GDT_KERN_DS32 0x2
 #define GDT_KERN_CS64 0x3
 
+#define GDT_RMODE_CS16 0x4
+#define GDT_RMODE_DS16 0x5
+
 #define GDT_BOOT_TSS    0x4
 #define GDT_BOOT_TSS_DF 0x5
 
@@ -46,13 +49,17 @@
 
 #define GDT_PERCPU 0x9
 
-#define NR_BOOT_GDT_ENTRIES 6
-#define NR_GDT_ENTRIES      10
+#define NR_BOOT_GDT_ENTRIES  6
+#define NR_RMODE_GDT_ENTRIES 8
+#define NR_GDT_ENTRIES       10
 
 #define __KERN_CS32 (GDT_KERN_CS32 << 3)
 #define __KERN_DS32 (GDT_KERN_DS32 << 3)
 #define __KERN_CS64 (GDT_KERN_CS64 << 3)
 
+#define __KERN_CS16 (GDT_RMODE_CS16 << 3)
+#define __KERN_DS16 (GDT_RMODE_DS16 << 3)
+
 #define __USER_CS32 ((GDT_USER_CS32 << 3) | 3)
 #define __USER_DS32 ((GDT_USER_DS32 << 3) | 3)
 #define __USER_CS64 ((GDT_USER_CS64 << 3) | 3)