From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [3/3] x86/MCE/AMD: Get address from already initialized block From: Johannes Hirte Message-Id: <20180517064930.GA26421@probook> Date: Thu, 17 May 2018 08:49:31 +0200 To: Borislav Petkov Cc: "Ghannam, Yazen" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "tony.luck@intel.com" , "x86@kernel.org" List-ID: T24gMjAxOCBNYWkgMTcsIEJvcmlzbGF2IFBldGtvdiB3cm90ZToKPiBPbiBUdWUsIE1heSAxNSwg MjAxOCBhdCAxMTozOTo1NEFNICswMjAwLCBKb2hhbm5lcyBIaXJ0ZSB3cm90ZToKPiA+IFRoZSBv dXQtb2YtYm91bmQgYWNjZXNzIGhhcHBlbnMgaW4gZ2V0X2Jsb2NrX2FkZHJlc3M6Cj4gPiAKPiA+ IAlpZiAoYmFua3AgJiYgYmFua3AtPmJsb2Nrcykgewo+ID4gCQlzdHJ1Y3QgdGhyZXNob2xkX2Js b2NrICpibG9ja3AgYmxvY2twID0gJmJhbmtwLT5ibG9ja3NbYmxvY2tdOwo+ID4gCj4gPiB3aXRo IGJsb2NrPTEuIFRoaXMgZG9lc24ndCBleGlzdHMuIEkgZG9uJ3QgZXZlbiBmaW5kIGFueSBhcnJh eSBoZXJlLgo+ID4gVGhlcmUgaXMgYSBsaW5rZWQgbGlzdCwgY3JlYXRlZCBpbiBhbGxvY2F0ZV90 aHJlc2hvbGRfYmxvY2tzLiBPbiBteQo+ID4gc3lzdGVtIEkgZ2V0IDE3IGxpc3RzIHdpdGggb25l IGVsZW1lbnQgZWFjaC4KPiAKPiBZZXMsIHdoYXQgYSBtZXNzIHRoaXMgaXMuIDstXAo+IAo+IFRo ZXJlJ3Mgbm8gc3VjaCB0aGluZyBhcyAtPmJsb2Nrc1tibG9ja10gYXJyYXkuIFdlIGFzc2lnbiBz aW1wbHkgdGhlCj4gdGhyZXNob2xkX2Jsb2NrIHRvIGl0IGluIGFsbG9jYXRlX3RocmVzaG9sZF9i bG9ja3M6Cj4gCj4gCXBlcl9jcHUodGhyZXNob2xkX2JhbmtzLCBjcHUpW2JhbmtdLT5ibG9ja3Mg PSBiOwo+IAo+IEFuZCBJIGNhbid0IHNheSB0aGUgZGVzaWduIG9mIHRoaXMgdGhpbmcgaXMgcmVh bGx5IGZyaWVuZGx5IGJ1dCBpdCBpcwo+IHN0aWxsIG5vIGV4Y3VzZSB0aGF0IEkgbWlzc2VkIHRo YXQgZHVyaW5nIHJldmlldy4gR3Jyci4KPiAKPiBTbywgWWF6ZW4sIHdoYXQgcmVhbGx5IG5lZWRz IHRvIGhhcHBlbiBoZXJlIGlzIHRvIGl0ZXJhdGUgdGhlCj4gYmFuay0+YmxvY2tzLT5taXNjaiBs aXN0IHRvIGZpbmQgdGhlIGJsb2NrIHlvdSdyZSBsb29raW5nIGZvciBhbmQgcmV0dXJuCj4gaXRz IGFkZHJlc3MsIHRoZSBvcHBvc2l0ZSB0byB0aGlzIGhlcmU6Cj4gCj4gICAgICAgICBpZiAocGVy X2NwdSh0aHJlc2hvbGRfYmFua3MsIGNwdSlbYmFua10tPmJsb2Nrcykgewo+ICAgICAgICAgICAg ICAgICBsaXN0X2FkZCgmYi0+bWlzY2osCj4gICAgICAgICAgICAgICAgICAgICAgICAgICZwZXJf Y3B1KHRocmVzaG9sZF9iYW5rcywgY3B1KVtiYW5rXS0+YmxvY2tzLT5taXNjaik7Cj4gICAgICAg ICB9IGVsc2Ugewo+ICAgICAgICAgICAgICAgICBwZXJfY3B1KHRocmVzaG9sZF9iYW5rcywgY3B1 KVtiYW5rXS0+YmxvY2tzID0gYjsKPiAgICAgICAgIH0KPiAKPiBhbmQgZG9uJ3QgZm9yZ2V0IHRv IGxvb2sgYXQgLT5ibG9ja3MgaXRzZWxmLgo+IAo+IEFuZCB0aGVuIHlvdSBuZWVkIHRvIG1ha2Ug c3VyZSB0aGF0IHNlYXJjaGluZyBmb3IgYmxvY2sgYWRkcmVzc2VzIHN0aWxsCj4gd29ya3Mgd2hl biByZXN1bWluZyBmcm9tIHN1c3BlbmQgc28gdGhhdCB5b3UgY2FuIGF2b2lkIHRoZSBSRE1TUiBJ UElzLgo+IAoKTWF5YmUgSSdtIG1pc3Npbmcgc29tZXRoaW5nLCBidXQgdGhvc2UgUkRNU1IgSVBT cyBkb24ndCBoYXBwZW4gb24KcHJlLVNNQ0Egc3lzdGVtcywgcmlnaHQ/IFNvIHRoZSBjYWNoaW5n IHNob3VsZCBiZSBhdm9pZGVkIGhlcmUsIGNhdXNlCnRoZSB3aG9sZSBsb29rdXAgbG9va3MgbW9y ZSBleHBlbnNpdmUgdG8gbWUgdGhhbiB0aGUgc2ltcGxlIHN3aXRjaC1ibG9jawppbiBnZXRfYmxv Y2tfYWRkcmVzcy4K From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752452AbeEQGtm (ORCPT ); Thu, 17 May 2018 02:49:42 -0400 Received: from freki.datenkhaos.de ([81.7.17.101]:37096 "EHLO freki.datenkhaos.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751995AbeEQGtk (ORCPT ); Thu, 17 May 2018 02:49:40 -0400 Date: Thu, 17 May 2018 08:49:31 +0200 From: Johannes Hirte To: Borislav Petkov Cc: "Ghannam, Yazen" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "tony.luck@intel.com" , "x86@kernel.org" Subject: Re: [PATCH 3/3] x86/MCE/AMD: Get address from already initialized block Message-ID: <20180517064930.GA26421@probook> References: <20180201184813.82253-1-Yazen.Ghannam@amd.com> <20180201184813.82253-3-Yazen.Ghannam@amd.com> <20180414004230.GA2033@probook> <20180416115624.GA1543@probook> <20180515093953.GA1746@probook> <20180516224641.GA31929@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180516224641.GA31929@pd.tnic> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018 Mai 17, Borislav Petkov wrote: > On Tue, May 15, 2018 at 11:39:54AM +0200, Johannes Hirte wrote: > > The out-of-bound access happens in get_block_address: > > > > if (bankp && bankp->blocks) { > > struct threshold_block *blockp blockp = &bankp->blocks[block]; > > > > with block=1. This doesn't exists. I don't even find any array here. > > There is a linked list, created in allocate_threshold_blocks. On my > > system I get 17 lists with one element each. > > Yes, what a mess this is. ;-\ > > There's no such thing as ->blocks[block] array. We assign simply the > threshold_block to it in allocate_threshold_blocks: > > per_cpu(threshold_banks, cpu)[bank]->blocks = b; > > And I can't say the design of this thing is really friendly but it is > still no excuse that I missed that during review. Grrr. > > So, Yazen, what really needs to happen here is to iterate the > bank->blocks->miscj list to find the block you're looking for and return > its address, the opposite to this here: > > if (per_cpu(threshold_banks, cpu)[bank]->blocks) { > list_add(&b->miscj, > &per_cpu(threshold_banks, cpu)[bank]->blocks->miscj); > } else { > per_cpu(threshold_banks, cpu)[bank]->blocks = b; > } > > and don't forget to look at ->blocks itself. > > And then you need to make sure that searching for block addresses still > works when resuming from suspend so that you can avoid the RDMSR IPIs. > Maybe I'm missing something, but those RDMSR IPSs don't happen on pre-SMCA systems, right? So the caching should be avoided here, cause the whole lookup looks more expensive to me than the simple switch-block in get_block_address. -- Regards, Johannes