From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([66.187.233.31]) by bombadil.infradead.org with esmtp (Exim 4.68 #1 (Red Hat Linux)) id 1Jwjm4-0008Is-Bu for kexec@lists.infradead.org; Thu, 15 May 2008 20:10:00 +0000 Date: Thu, 15 May 2008 16:09:23 -0400 From: Vivek Goyal Subject: Re: [PATCH -mm] kexec jump -v9 Message-ID: <20080515200923.GC9718@redhat.com> References: <1204773188.4707.109.camel@caritas-dev.intel.com> <20080514205204.GJ30469@redhat.com> <1210818762.23707.102.camel@caritas-dev.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1210818762.23707.102.camel@caritas-dev.intel.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: "Huang, Ying" Cc: nigel@nigel.suspend2.net, Kexec Mailing List , linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , "Eric W. Biederman" , Pavel Machek , Andrew Morton , linux-pm@lists.linux-foundation.org Wy4uXQo+ID4gPiArMjoKPiA+ID4gKwljYWxsCSolZWR4Cj4gPiAKPiA+ID4gKwltb3ZsCSVlZGks ICVlZHgKPiA+ID4gKwlwb3BsCSVlZGkKPiA+ID4gKwlwdXNobAklZWR4Cj4gPiA+ICsJam1wCTJi Cj4gPiA+ICsKPiA+IAo+ID4gV2hhdCBkb2VzIGFib3ZlIHBpZWNlIG9mIGNvZGUgZG8/IExvb2tz IGxpa2UgcmVkdW5kYW50IGZvciBzd2l0Y2hpbmcKPiA+IGJldHdlZW4gdGhlIGtlcm5lbHM/IEFm dGVyIGNhbGwgKiVlZHgsIHdlIG5ldmVyIHJldHVybiBoZXJlLiBJbnN0ZWFkCj4gPiB3ZSBjb21l IGJhY2sgdG8gImtleGVjX2p1bXBfYmFja19lbnRyeSI/Cj4gCj4gRm9yIHN3aXRjaGluZyBiZXR3 ZWVuIHRoZSBrZXJuZWxzLCB0aGlzIGlzIHJlZHVuZGFudC4gT3JpZ2luYWxseSBhbm90aGVyCj4g ZmVhdHVyZSBvZiBrZXhlYyBqdW1wIGlzIHRvIGNhbGwgc29tZSBjb2RlIGluIHBoeXNpY2FsIG1v ZGUuIO+7v1RoaXMgaXMKPiB1c2VkIHRvIHByb3ZpZGUgYSBDIEFCSSB0byBjYWxsZWQgY29kZS4K PiAKCkhpIEh1YW5nLAoKT2ssIFlvdSB3YW50IHRvIG1ha2UgQklPUyBjYWxscy4gV2UgYWxyZWFk eSBkbyB0aGF0IHVzaW5nIHZtODYgbW9kZSBhbmQKdXNlIGJpb3MgcmVhbCBtb2RlIGludGVycnVw dHMuIFNvIHdoeSBkbyB3ZSBuZWVkIHRoaXMgaW50ZXJmYWNlPyBPciwgSU9XLApob3cgaXMgdGhp cyBpbnRlcmZhY2UgYmV0dGVyPwoKRG8geW91IGhhdmUgc29tZXRoaW5nIGluIG1pbmQgd2hlcmUv aG93IGFyZSB5b3UgZ29pbmcgdG8gdXNlIGl0PwoKVGhhbmtzClZpdmVrCgpfX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwprZXhlYyBtYWlsaW5nIGxpc3QKa2V4 ZWNAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFkLm9yZy9tYWlsbWFu L2xpc3RpbmZvL2tleGVjCg== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762666AbYEOUKw (ORCPT ); Thu, 15 May 2008 16:10:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753498AbYEOUKo (ORCPT ); Thu, 15 May 2008 16:10:44 -0400 Received: from mx1.redhat.com ([66.187.233.31]:49454 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752509AbYEOUKn (ORCPT ); Thu, 15 May 2008 16:10:43 -0400 Date: Thu, 15 May 2008 16:09:23 -0400 From: Vivek Goyal To: "Huang, Ying" Cc: "Eric W. Biederman" , Pavel Machek , nigel@nigel.suspend2.net, "Rafael J. Wysocki" , Andrew Morton , linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, Kexec Mailing List Subject: Re: [PATCH -mm] kexec jump -v9 Message-ID: <20080515200923.GC9718@redhat.com> References: <1204773188.4707.109.camel@caritas-dev.intel.com> <20080514205204.GJ30469@redhat.com> <1210818762.23707.102.camel@caritas-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1210818762.23707.102.camel@caritas-dev.intel.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [..] > > > +2: > > > + call *%edx > > > > > + movl %edi, %edx > > > + popl %edi > > > + pushl %edx > > > + jmp 2b > > > + > > > > What does above piece of code do? Looks like redundant for switching > > between the kernels? After call *%edx, we never return here. Instead > > we come back to "kexec_jump_back_entry"? > > For switching between the kernels, this is redundant. Originally another > feature of kexec jump is to call some code in physical mode. This is > used to provide a C ABI to called code. > Hi Huang, Ok, You want to make BIOS calls. We already do that using vm86 mode and use bios real mode interrupts. So why do we need this interface? Or, IOW, how is this interface better? Do you have something in mind where/how are you going to use it? Thanks Vivek