From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-124878-1519695015-2-16960624006241364265 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='net', MailFrom='org' X-Spam-charsets: plain='utf-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519695014; b=fWRoNJkNZd8IrRngMdunkdYSGS4yuDZnD51CpR6RvAxhXsJ mYFxcPDwYhMSrYQCnqIOJ9uuSu9nXm1Sa7p8Sb7KvT7cU3xscpbHfP883NM/7pV5 O9AKtZAgFsfBpH5ShEA/6qz7UYJv9IyCu2cHDeC6Qf6ZDUON9xAtSrQbxvHPCyMb xP5amHlhVkAfjHsFG3F19nQnP8exmB9oWVkZOCSj8rZM/BaFPo5/NzKVX17qCH9R nKFpEUo89YYN0LC6/RyFp6ILvEqDfz3GA2U9GpJj1rwRnku/VSvUI238Z9cwJ9S9 gP9eIumSEdVFQUzmqaCLri86HkKuJ+WgMFybvhA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=subject:to:cc:references:from:message-id :date:mime-version:in-reply-to:content-type :content-transfer-encoding:sender:list-id; s=arctest; t= 1519695014; bh=smpyBdHV6WbsclIsWuucLPDtYOgwOiKUs2WLY3OTqh0=; b=P GXukYT1jf6QrHVbNgWtYyb8+sPo+GXwbTjTNz6Cn+eoTarDOrUPDgPVXM65kbTRW LhiyKpy/dgQyTHU53Sb0CWg4knWTMhVmv4qo139/jF6qBHHFqUZBDm9gG3oIJj/7 bsAglBHQb5ut4bB4UWoKlzXTriweEbWpP97dk99elF01I0IKt7hYp2TyFFtuP+GR sqvXXiM2YNqu/Pomg7S8RbBSw52k2ELz4gCHvuFvqW9SJClkZkLSowjEVJ50VBxX NRF/9u5H2mUgMdxhIirN4/4GyzsfaACmzCu5L6wujCLTl3+FxjWvx0cNa9+cvmUb RwQbAGIcNzuJ9hNHgW2jg== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=fail (message has been altered; 2048-bit rsa key sha256) header.d=gmail.com header.i=@gmail.com header.b=b47lcP+Z x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=none (p=none,has-list-id=yes,d=none) header.from=roeck-us.net; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=fail (message has been altered; 2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=rp4y/m5O; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=roeck-us.net header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=fail (message has been altered; 2048-bit rsa key sha256) header.d=gmail.com header.i=@gmail.com header.b=b47lcP+Z x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=none (p=none,has-list-id=yes,d=none) header.from=roeck-us.net; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=fail (message has been altered; 2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=rp4y/m5O; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=roeck-us.net header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751566AbeB0BaA (ORCPT ); Mon, 26 Feb 2018 20:30:00 -0500 Received: from mail-pl0-f65.google.com ([209.85.160.65]:39144 "EHLO mail-pl0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751463AbeB0B36 (ORCPT ); Mon, 26 Feb 2018 20:29:58 -0500 X-Google-Smtp-Source: AH8x225JQhxtG1qPy+G5l/YpUn42zmfannTfA5OM69B0qNRnL0HNhe5Qa9YQSrZvxVKWLf0+8pewJw== Subject: Re: [PATCH v5 2/9] watchdog/hpwdt: Remove legacy NMI sourcing. To: Jerry.Hoemann@hpe.com Cc: Arnd Bergmann , Wim Van Sebroeck , linux-watchdog@vger.kernel.org, Linux Kernel Mailing List , rwright@hpe.com, maurice.a.saldivar@hpe.com, Ingo Molnar , marcus.folkesson@gmail.com, Josh Poimboeuf , stable References: <20180226032227.14615-1-jerry.hoemann@hpe.com> <20180226032227.14615-3-jerry.hoemann@hpe.com> <03b13d44-9ce3-ead8-020d-4b1b8114079d@roeck-us.net> <20180227010250.GC8244@anatevka.americas.hpqcorp.net> From: Guenter Roeck Message-ID: <8766f2ee-428a-d72f-b0c3-e5fe68fd0a33@roeck-us.net> Date: Mon, 26 Feb 2018 17:29:55 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180227010250.GC8244@anatevka.americas.hpqcorp.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 02/26/2018 05:02 PM, Jerry Hoemann wrote: > On Mon, Feb 26, 2018 at 06:32:30AM -0800, Guenter Roeck wrote: >> On 02/26/2018 06:11 AM, Arnd Bergmann wrote: >>> On Mon, Feb 26, 2018 at 4:22 AM, Jerry Hoemann wrote: >>>> Gen8 and prior Proliant systems supported the "CRU" interface >>>> to firmware. This interfaces allows linux to "call back" into firmware >>>> to source the cause of an NMI. This feature isn't fully utilized >>>> as the actual source of the NMI isn't printed, the driver only >>>> indicates that the source couldn't be determined when the call >>>> fails. >>>> >>>> With the advent of Gen9, iCRU replaces the CRU. The call back >>>> feature is no longer available in firmware. To be compatible and >>>> not attempt to call back into firmware on system not supporting CRU, >>>> the SMBIOS table is consulted to determine if it is safe to >>>> make the call back or not. >>>> >>>> This results in about half of the driver code being devoted >>>> to either making CRU calls or determing if it is safe to make >>>> CRU calls. As noted, the driver isn't really using the results of >>>> the CRU calls. >>>> >>>> Furthermore, as a consequence of the Spectre security issue, the >>>> BIOS/EFI calls are being wrapped into Spectre-disabling section. >>>> Removing the call back in hpwdt_pretimeout assists in this effort. >>>> >>>> As the CRU sourcing of the NMI isn't required for handling the >>>> NMI and there are security concerns with making the call back, remove >>>> the legacy (pre Gen9) NMI sourcing and the DMI code to determine if >>>> the system had the CRU interface. >>>> >>>> Signed-off-by: Jerry Hoemann >>> >>> This avoids a warning in mainline kernels, so that's great: >>> >>> drivers/watchdog/hpwdt.o: warning: objtool: .text+0x24: indirect call >>> found in RETPOLINE build >>> >>> I wonder what we do about stable kernels. Are both this patch and the patch >>> that added the objtool warning message candidates for backports to >>> stable kernels? >>> >> >> Makes sense to me, but it is really a bit more than a bug fix, so I'll >> leave it up to Jerry/HPE to make the call in respect to hpwdt. >> > > Generally speaking, HPE customers who run linux do so through a distro > vendor and pick up patches from them. But I'm sure there are some > customers who do things differently. > > The distro vendor's have their own repos and we'll work with them > to back port patches to their code base. So, I typically don't do a lot > of kernel.org stable branch work. > > Looks like objtool has been enhanced to find Spectre vulnerable code. > Are the other kernel patches related to Spectre being back ported > to stable release lines? If yes, it probably make sense to do > the hpwdt change as well. > Spectre has been backported to v4.4 and later. I don't know about earlier kernels. > Is just the patch removing the firmware call back wanted/needed? Or the > whole driver rewrite? (The older baseline don't have all the watchdog > features that the patch set uses.) > We would only want to backport this patch. The rest is really out of scope. > Which stable baseline(s) would need to be patched? Priority? > > Who does it? (i.e. do you want me to submit patches to the stable baseline?) > We would tag the patch for stable (and submit it into v4.16-rc). Greg would take care of the rest unless there are conflicts, in which case we get a note telling us that a backport is needed. Guenter