From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1JJ8rb-00060F-Bf for mharc-grub-devel@gnu.org; Sun, 27 Jan 2008 09:52:03 -0500 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JJ8ra-0005zb-71 for grub-devel@gnu.org; Sun, 27 Jan 2008 09:52:02 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JJ8rY-0005z8-JI for grub-devel@gnu.org; Sun, 27 Jan 2008 09:52:01 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JJ8rY-0005z5-DU for grub-devel@gnu.org; Sun, 27 Jan 2008 09:52:00 -0500 Received: from pne-smtpout4-sn2.hy.skanova.net ([81.228.8.154]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1JJ8rY-0005YA-3k for grub-devel@gnu.org; Sun, 27 Jan 2008 09:52:00 -0500 Received: from [127.0.0.1] (88.193.32.97) by pne-smtpout4-sn2.hy.skanova.net (7.3.129) id 478BE663000ADB32 for grub-devel@gnu.org; Sun, 27 Jan 2008 15:51:47 +0100 Message-ID: <479C9A92.70109@nic.fi> Date: Sun, 27 Jan 2008 16:52:02 +0200 From: =?UTF-8?B?VmVzYSBKw6TDpHNrZWzDpGluZW4=?= User-Agent: Thunderbird 2.0.0.9 (Windows/20071031) MIME-Version: 1.0 To: The development of GRUB 2 X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: Quoted-Printable X-detected-kernel: by monty-python.gnu.org: Solaris 10 (beta) Subject: Odd behavior in x86/pc booting process with minor modifications X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 27 Jan 2008 14:52:02 -0000 Hi, I was playing around with IDT and needed some code space in startup.S=20 and in realmode.S. GRUB just hanged for some reason during the bootup=20 when I just had query instruction for current IDT descriptor and some=20 storage for it after GDT tables. I then reverted that code and added as many NOPs as that code would take=20 there and it was still hanging... then I removed some NOPs and hang went=20 away. I don't have good debugging capabilities other than qemu's log,=20 but it would seem like when grub is decompressing itself there is minor=20 code flow difference, though this could only be because binary is a bit=20 different... so I am not sure about that theory... anyway if there are=20 good ideas on how to debug this, or even better solutions to possible=20 problem :). Any ideas are welcome. So how to reproduce this problem: 1. open kern/i386/pc/startup.S 2. find codestart // actual location is not so important 3. find first sti instruction 4. go 1 line backwards 5. add about 15 NOP's 6. recompile and make image 7. try it out, it should hang without displaying grub shell or menu. Thanks, Vesa J=C3=A4=C3=A4skel=C3=A4inen