From f9eb40dbfbc9efcc197b0566f371dc5a880d7a9f Mon Sep 17 00:00:00 2001
From: Mark <alnyan@airmail.cc>
Date: Sat, 19 Sep 2020 17:18:39 +0300
Subject: [PATCH] cpu: properly reload segment registers after lgdt

---
 arch/amd64/hw/gdt_s.S | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/arch/amd64/hw/gdt_s.S b/arch/amd64/hw/gdt_s.S
index e8c030d..d451540 100644
--- a/arch/amd64/hw/gdt_s.S
+++ b/arch/amd64/hw/gdt_s.S
@@ -2,7 +2,27 @@
 .global amd64_gdt_load
 amd64_gdt_load:
     lgdt (%rdi)
-    // Not sure if CS reload is needed
     movw $0x28, %ax
     ltr %ax
-    retq
+
+    mov %rsp, %rdx
+    mov $0x10, %rax
+    push %rax
+    push %rdx
+
+    pushf
+
+    mov $0x08, %rax
+    push %rax
+    lea 1f(%rip), %rax
+    push %rax
+
+    iretq
+
+1:
+    mov $0x10, %rax
+    mov %rax, %ds
+    mov %rax, %es
+    mov %rax, %fs
+    mov %rax, %gs
+    ret