linux-kernel - Re: [PATCH] Make bootsector stub 16-bit-only (i386)

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Message-ID: <463CC7FD.6090006@zytor.com>
Date:	Sat, 05 May 2007 11:07:57 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Alexander van Heukelum <heukelum@...lshack.com>
CC:	Andi Kleen <ak@...e.de>, Andrew Morton <akpm@...ux-foundation.org>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Make bootsector stub 16-bit-only (i386)

Acked-by: H. Peter Anvin <hpa@...or.com>

Alexander van Heukelum wrote:
> Hi!
> 
> The x86 bzImage contains a stub to inform people that it is not possible
> any more to run a Linux kernel by catting it to a floppy and then
> booting from it. This was meant to be all 16-bit code. The first
> instruction, however, ended up as being coded as a 16:32-bit far jump. I
> assume the intention was a 16:16-bit far jump.
> 
> This patch changes only i386.
> 
> Greetings,
> 	Alexander
> 
> Signed-off-by: Alexander van Heukelum <heukelum@...lshack.com>
> 
> ---
> 
> diff --git a/arch/i386/boot/bootsect.S b/arch/i386/boot/bootsect.S
> index 011b7a4..ae9df0d 100644
> --- a/arch/i386/boot/bootsect.S
> +++ b/arch/i386/boot/bootsect.S
> @@ -44,7 +44,7 @@ #endif
>  _start:
>  
>  	# Normalize the start address
> -	jmpl	$BOOTSEG, $start2
> +	jmpw	$BOOTSEG, $start2
>  
>  start2:
>  	movw	%cs, %ax
-
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