From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752318Ab2KVXem (ORCPT ); Thu, 22 Nov 2012 18:34:42 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:38322 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752018Ab2KVXej (ORCPT ); Thu, 22 Nov 2012 18:34:39 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Yinghai Lu Cc: "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, Matt Fleming References: <1353482170-10160-1-git-send-email-yinghai@kernel.org> <1353482170-10160-2-git-send-email-yinghai@kernel.org> <50AD0E22.3020807@zytor.com> <50AD307C.6060008@zytor.com> Date: Wed, 21 Nov 2012 21:48:51 -0800 In-Reply-To: (Yinghai Lu's message of "Wed, 21 Nov 2012 12:15:28 -0800") Message-ID: <87d2z6jigs.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX19XaHEHVL0tyc8ljmeeMEOfKIdlJApNfbo= X-SA-Exim-Connect-IP: 75.135.205.0 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 TVD_RCVD_IP TVD_RCVD_IP * 0.1 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject * 0.0 T_TooManySym_03 6+ unique symbols in subject * 0.0 T_TooManySym_02 5+ unique symbols in subject X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Yinghai Lu X-Spam-Relay-Country: Subject: Re: [PATCH v3 01/12] x86, boot: move verify_cpu.S after 0x200 X-SA-Exim-Version: 4.2.1 (built Sun, 08 Jan 2012 03:05:19 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yinghai Lu writes: > On Wed, Nov 21, 2012 at 11:50 AM, H. Peter Anvin wrote: >> The comment is just plain wrong. It assumes you're loading an ELF file, >> whereas in practice that is rarely true. >> >> This does explain why the poor ABI, though. A jump table at the >> beginning would have been a lot cleaner. > > Can you please have patch to update the comments and point to the API there ? Long ago and far away. I wrote the 64bit entry code for a bzImage by putting an ELF header in the boot sector. That is what that comment referred to when it was written. Andrew had a problem on one of his test machines and so the patch to bootsector was dropped. Booting with a vmlinux file does (or at least should not) need this. ELF loaders will pick the entry point out from the ELF header. I don't know what has happened in the intervening time, or who if anyone has depended on that offset. The original intent an internal use hard code. Eric