From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753330AbYDGSip (ORCPT ); Mon, 7 Apr 2008 14:38:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751369AbYDGSig (ORCPT ); Mon, 7 Apr 2008 14:38:36 -0400 Received: from smtp-outbound-1.vmware.com ([65.113.40.141]:35164 "EHLO smtp-outbound-1.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750949AbYDGSif (ORCPT ); Mon, 7 Apr 2008 14:38:35 -0400 Subject: Re: [PATCH] Fix paranoia about using BIOS quickboot mechanism. From: Alok Kataria To: Ingo Molnar Cc: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org, Daniel Arai , Zachary Amsden In-Reply-To: <20080407082256.GA3524@elte.hu> References: <1207352954.6294.30.camel@promb-2n-dhcp158.eng.vmware.com> <20080407082256.GA3524@elte.hu> Content-Type: multipart/mixed; boundary="=-BPR2jdaO5DxFwK2JUi/0" Organization: VMware, Inc. Date: Mon, 07 Apr 2008 11:38:33 -0700 Message-Id: <1207593513.5864.25.camel@promb-2n-dhcp158.eng.vmware.com> Mime-Version: 1.0 X-Mailer: Evolution 2.8.0 (2.8.0-40.el5) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-BPR2jdaO5DxFwK2JUi/0 Content-Type: text/plain Content-Transfer-Encoding: 7bit On Mon, 2008-04-07 at 10:22 +0200, Ingo Molnar wrote: > * Alok Kataria wrote: > > > Make sure that we clear the "shutdown status flag" in the CMOS > > register after each CPU is brought up. This fixes a problem where the > > "shutdown status flag" may remain set when a CPU is brought up after > > booting. > > btw., what problem does this result in, exactly? The shutdown status flag set to "0xA", corresponds to "JMP double word request without INT init". This JMP at reboot time is at an unintended location. And results in Triple faults in our case. Though this error at reboot can be safely ignored in a VM environment, am not sure what the effect would be on a physical system. May be it will result in a triple fault and an eventual hardware reset thus masking this BUG in the kernel. This fix just makes sure that we reset that status flag after initialization is done. > > > Tested on the X86 tree. > > > + * Cleanup possible dangling ends... > > + */ > > + smpboot_restore_warm_reset_vector(); > > + > > return boot_error; > > } > > patch got whitespace damaged - have a look at > Documentation/email-clients.txt for details about how to send patches as > in-line text. (or send the patch as an attachment - we accept x86 > patches as attachments too) Ah...I think i followed the instructions there, will have to look what went wrong, anyways, will go for the easier solution, here is the patch attached. Thanks & Regards, Alok > > Ingo --=-BPR2jdaO5DxFwK2JUi/0 Content-Disposition: attachment; filename=fix-reboot-after-cpu-hotplug.patch Content-Type: text/x-patch; name=fix-reboot-after-cpu-hotplug.patch; charset=utf-8 Content-Transfer-Encoding: base64 Rml4IHBhcmFub2lhIGFib3V0IHVzaW5nIEJJT1MgcXVpY2tib290IG1lY2hhbmlzbS4NCg0KTWFr ZSBzdXJlIHRoYXQgd2UgY2xlYXIgdGhlICJzaHV0ZG93biBzdGF0dXMgZmxhZyIgaW4gdGhlIENN T1MgcmVnaXN0ZXINCmFmdGVyIGVhY2ggQ1BVIGlzIGJyb3VnaHQgdXAuICBUaGlzIGZpeGVzIGEg cHJvYmxlbSB3aGVyZSB0aGUgInNodXRkb3duDQpzdGF0dXMgZmxhZyIgbWF5IHJlbWFpbiBzZXQg d2hlbiBhIENQVSBpcyBicm91Z2h0IHVwIGFmdGVyIGJvb3RpbmcuDQoNClNpZ25lZC1vZmYtYnk6 IEFsb2sgTiBLYXRhcmlhIDxha2F0YXJpYUB2bXdhcmUuY29tPg0KU2lnbmVkLW9mZi1ieTogRGFu IEFyYWkgPGFyYWlAdm13YXJlLmNvbT4NCg0KLS0tDQogYXJjaC94ODYva2VybmVsL3NtcGJvb3Qu YyB8ICAgMTAgKysrKystLS0tLQ0KIDEgZmlsZXMgY2hhbmdlZCwgNSBpbnNlcnRpb25zKCspLCA1 IGRlbGV0aW9ucygtKQ0KDQpkaWZmIC0tZ2l0IGEvYXJjaC94ODYva2VybmVsL3NtcGJvb3QuYyBi L2FyY2gveDg2L2tlcm5lbC9zbXBib290LmMNCmluZGV4IDUzMjFlMzUuLjBiOGJiYTggMTAwNjQ0 DQotLS0gYS9hcmNoL3g4Ni9rZXJuZWwvc21wYm9vdC5jDQorKysgYi9hcmNoL3g4Ni9rZXJuZWwv c21wYm9vdC5jDQpAQCAtMTAxMCw2ICsxMDEwLDExIEBAIGRvX3Jlc3Q6DQogCS8qIG1hcmsgInN0 dWNrIiBhcmVhIGFzIG5vdCBzdHVjayAqLw0KIAkqKCh2b2xhdGlsZSB1bnNpZ25lZCBsb25nICop dHJhbXBvbGluZV9iYXNlKSA9IDA7DQogDQorCS8qDQorCSAqIENsZWFudXAgcG9zc2libGUgZGFu Z2xpbmcgZW5kcy4uLg0KKwkgKi8NCisJc21wYm9vdF9yZXN0b3JlX3dhcm1fcmVzZXRfdmVjdG9y KCk7DQorDQogCXJldHVybiBib290X2Vycm9yOw0KIH0NCiANCkBAIC0xMjYzLDExICsxMjY4LDYg QEAgdm9pZCBfX2luaXQgbmF0aXZlX3NtcF9wcmVwYXJlX2Jvb3RfY3B1KHZvaWQpDQogDQogdm9p ZCBfX2luaXQgbmF0aXZlX3NtcF9jcHVzX2RvbmUodW5zaWduZWQgaW50IG1heF9jcHVzKQ0KIHsN Ci0JLyoNCi0JICogQ2xlYW51cCBwb3NzaWJsZSBkYW5nbGluZyBlbmRzLi4uDQotCSAqLw0KLQlz bXBib290X3Jlc3RvcmVfd2FybV9yZXNldF92ZWN0b3IoKTsNCi0NCiAJRHByaW50aygiQm9vdCBk b25lLlxuIik7DQogDQogCWltcHJlc3NfZnJpZW5kcygpOw0KLS0gDQoxLjUuNA0KDQo= --=-BPR2jdaO5DxFwK2JUi/0--