From: Michael Brown <mcb30@etherboot.org>
Date: Tue, 6 Jun 2006 15:30:28 +0000 (+0000)
Subject: Code segment may not be writable; create the temporary pointer to the GDT
X-Git-Tag: v0.9.3~1299
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e7eca7b7cbd3354916145c36ca88e9e754ef8812;p=thirdparty%2Fipxe.git

Code segment may not be writable; create the temporary pointer to the GDT
on the stack.
---

diff --git a/src/arch/i386/prefix/libprefix.S b/src/arch/i386/prefix/libprefix.S
index 10227818c..f0f7682b5 100644
--- a/src/arch/i386/prefix/libprefix.S
+++ b/src/arch/i386/prefix/libprefix.S
@@ -254,6 +254,7 @@ flatten_real_mode:
 	/* Preserve real-mode segment values and temporary registers */
 	pushw	%es
 	pushw	%ds
+	pushw	%bp
 	pushl	%eax
 
 	/* Set GDT base and load GDT */
@@ -261,8 +262,11 @@ flatten_real_mode:
 	movw	%cs, %ax
 	shll	$4, %eax
 	addl	$gdt, %eax
-	movl	%eax, %cs:gdt_base
-	lgdt	%cs:gdt
+	pushl	%eax
+	pushw	%cs:gdt_limit
+	movw	%sp, %bp
+	lgdt	(%bp)
+	addw	$6, %sp
 
 	/* Switch to protected mode */
 	movl	%cr0, %eax
@@ -281,6 +285,7 @@ flatten_real_mode:
 
 	/* Restore real-mode segment values and temporary registers */
 	popl	%eax
+	popw	%bp
 	popw	%ds
 	popw	%es
 	ret