Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752683Ab0BUFp7 (ORCPT ); Sun, 21 Feb 2010 00:45:59 -0500 Received: from terminus.zytor.com ([198.137.202.10]:43832 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751075Ab0BUFp6 (ORCPT ); Sun, 21 Feb 2010 00:45:58 -0500 Message-ID: <4B80C892.9000303@zytor.com> Date: Sat, 20 Feb 2010 21:45:54 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Thunderbird/3.0.1 MIME-Version: 1.0 To: Graeme Russ CC: linux-kernel@vger.kernel.org Subject: Re: x86 embedded - Problem getting past 'move compressed kernel before decompression' References: <4B80946D.1030503@gmail.com> In-Reply-To: <4B80946D.1030503@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1828 Lines: 62 On 02/20/2010 06:03 PM, Graeme Russ wrote: > > The following is something I have hacked together to jump into the 32-bit > start address of the Linux Kernel: > > struct boot_params boot_params __attribute__((aligned(16))); > struct setup_header *hdr = (struct setup_header *)(0x90000 + 0x1f1); > > void boot_zimage(void *setup_base) > { > memset(&boot_params, 0x00, sizeof boot_params); > memcpy(&boot_params.hdr, hdr, sizeof (*hdr)); > > boot_params.alt_mem_k = 128 * 1024; > boot_params.e820_entries = 1; > boot_params.e820_map[0].addr = 0x00000000; > boot_params.e820_map[0].size = 128 * 1024; > boot_params.e820_map[0].type = 1; > > asm( "movw $0x18, %%cx\n" \ > "movl %%ecx, %%ds\n" \ > "movl %%ecx, %%es\n" \ > "movl %%ecx, %%fs\n" \ > "movl %%ecx, %%gs\n" \ > "movl %%ecx, %%ss\n" \ > "xorl %%ebp, %%ebp\n" \ > "xorl %%edi, %%edi\n" \ > "xorl %%ebx, %%ebx\n" \ > "movl %0, %%esi\n" ^^ > "movl $0x100000, %%eax\n" \ > "jmpl *%%eax" : : "r"(&boot_params)); ^ At this point you have probably clobbered the register that you have your boot_params in. Instead, do something like: asm volatile( "movl %0, %%ds\n" \ "movl %0, %%es\n" \ "movl %0, %%fs\n" \ "movl %0, %%gs\n" \ "movl %0, %%ss\n" \ "xorl %ebp, %ebp\n" \ "xorl %ebx, %ebx\n" \ "movl $0x100000, %%eax\n" \ "ljmpl $0x10,$0x100000" : : "S" (&boot_params), "D" (0), "c" (0x18)); -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/