From 27d4401372adad3b652cfaafc46a1fca1fcd7718 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Thu, 27 Jul 2017 11:01:54 +0200
Subject: [PATCH] avoid memory access by preloading image_size into r11

---
 arch/x86/kernel/entry.asm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/entry.asm b/arch/x86/kernel/entry.asm
index d80c9befc..a4c68e835 100644
--- a/arch/x86/kernel/entry.asm
+++ b/arch/x86/kernel/entry.asm
@@ -194,6 +194,7 @@ Lno_mbinfo:
     xor rcx, rcx
     mov rsi, 510*0x200000
     sub rsi, kernel_start
+    mov r11, QWORD [image_size]
 Lremap:
     mov QWORD [rdi], rax
     add rax, 0x200000
@@ -202,7 +203,7 @@ Lremap:
     ; note: the whole code segement has to fit in the first pgd
     cmp rcx, rsi
     jnb Lno_pml4_init
-    cmp rcx, QWORD [image_size]
+    cmp rcx, r11
     jb Lremap
 
 Lno_pml4_init: