From 59bba7624f6236fe7010e0b4da455724dede7304 Mon Sep 17 00:00:00 2001
From: Reto Buerki <reet@codelabs.ch>
Date: Wed, 11 Feb 2015 15:50:50 +0100
Subject: [PATCH] hw_x86_64: Set system control flags of cr0 register

Enable paging, write protection, caching and native FPU error reporting,
see Intel SDM Vol. 3A, section 2.5.
---
 repos/base-hw/src/core/spec/x86_64/kernel/crt0.s | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/repos/base-hw/src/core/spec/x86_64/kernel/crt0.s b/repos/base-hw/src/core/spec/x86_64/kernel/crt0.s
index 864754984..25e4cebe0 100644
--- a/repos/base-hw/src/core/spec/x86_64/kernel/crt0.s
+++ b/repos/base-hw/src/core/spec/x86_64/kernel/crt0.s
@@ -45,6 +45,15 @@
 	btsl $11, %eax
 	wrmsr
 
+	/* Enable paging, write protection, caching and FPU error reporting */
+	movl %cr0, %eax
+	btsl $5, %eax
+	btsl $16, %eax
+	btrl $29, %eax
+	btrl $30, %eax
+	btsl $31, %eax
+	movl %eax, %cr0
+
 	/*
 	 * Install initial temporary environment that is replaced later by the
 	 * environment that init_main_thread creates.