From ee1b06ea6aed979da3b4e6b6ffea98ad55a3c5c1 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@linux.intel.com>
Date: Fri, 18 Feb 2011 15:47:42 -0800
Subject: [PATCH] x86, reboot: Fix the use of passed arguments in 32-bit BIOS
 reboot

The initial version of this patch had %eax being a segment and %ecx
being the mode.  I had changed the interfaces, but not the actual
implementation!

Reported-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <AANLkTikxqk=HEw9R-Du=v-1ti1HDGAY9vaNUep2XARaz@mail.gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Matthieu Castet <castet.matthieu@free.fr>
---
 arch/x86/kernel/reboot_32.S | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/reboot_32.S b/arch/x86/kernel/reboot_32.S
index f242356a096e..29092b38d816 100644
--- a/arch/x86/kernel/reboot_32.S
+++ b/arch/x86/kernel/reboot_32.S
@@ -23,10 +23,14 @@ r_base = .
 1:	popl	%ebx
 	subl	$1b, %ebx
 
+	/* Compute the equivalent real-mode segment */
+	movl	%ebx, %ecx
+	shrl	$4, %ecx
+	
 	/* Patch post-real-mode segment jump */
-	movw	dispatch_table(%ebx,%ecx,2),%cx
-	movw	%cx, 101f(%ebx)
-	movw	%ax, 102f(%ebx)
+	movw	dispatch_table(%ebx,%eax,2),%ax
+	movw	%ax, 101f(%ebx)
+	movw	%cx, 102f(%ebx)
 
 	/* Set up the IDT for real mode. */
 	lidtl	machine_real_restart_idt(%ebx)
-- 
2.11.0