From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-40595-1519693388-2-13370524191495545072 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, ME_NOAUTH 0.01, 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='com', MailFrom='org' X-Spam-charsets: plain='us-ascii' 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=1519693388; b=e1xLneKizA187dX1zAtTtkRQd/5SyrLcZChAQ774pNNTVGR o77hfn8hvnNq/Xhd6P/L/gsBXSrp5drF45SgiWotnSjj6WxpducALK/2+3YJ6ugQ 2/8fK1RSx+4vr1OT4iVgh8GwKkGv27xAD9jRKIIyTnODfa36xhtt4+lI6bo7PSc9 PwFmkxHB41daoyrOb4CA70ZbBXTFuEskVt4yMGgqVIP6NpUSDm2rb0bj2Lo+JtbV 5IL7zlV/SUc4gOL5MzEvzddFpuo2duxOtWbBsKXNKBy6T0Zy1dnoPsVaTgwoOOcj TjVis3JmtjbrWThPO5Wl+QrMd7UYoZY37eKo9ag== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :reply-to:references:mime-version:content-type:in-reply-to :sender:list-id; s=arctest; t=1519693388; bh=vmSsGsXBEsMfu8KLl93 khwjefnkhtjNgHOIZcAK6hig=; b=UU72inpSMvMz3cEqiTq5SadjT0xb9461Zuj SC4I2ukY7RavskyDlgT7G+pxgueKGp7h1+uFv9D4uDyWnCZZFnUCTnQi2uA3/rqr 1wNFb9qQJ6Uw+P2ccmn75PL5wDfMP6q1PyCS9BynqvW6da4x4k1940fy3Sfq0MpF Ij7ojOpJLd/2UaUg9FzsJpk5RgDp3cQkmBhrEGL7FVCYnwc54EKyrYbVsqBJA/DD JrDWfJAb4Fx7un4nT//42d+OK/9p/JbSyGEhk5Pu4uEIDBoUkeaE1PXJLxKt7xG1 DPreaOgFdEpnxl9Tiv7y0CE6pi7/T5q1T2+yCRxC6hG8ayKSzLA== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=hpe.com; 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-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=hpe.com header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=hpe.com; 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-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=hpe.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751611AbeB0BDH (ORCPT ); Mon, 26 Feb 2018 20:03:07 -0500 Received: from g2t1383g.austin.hpe.com ([15.233.16.89]:52943 "EHLO g2t1383g.austin.hpe.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751514AbeB0BCy (ORCPT ); Mon, 26 Feb 2018 20:02:54 -0500 Date: Mon, 26 Feb 2018 18:02:50 -0700 From: Jerry Hoemann To: Guenter Roeck 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 Subject: Re: [PATCH v5 2/9] watchdog/hpwdt: Remove legacy NMI sourcing. Message-ID: <20180227010250.GC8244@anatevka.americas.hpqcorp.net> Reply-To: Jerry.Hoemann@hpe.com References: <20180226032227.14615-1-jerry.hoemann@hpe.com> <20180226032227.14615-3-jerry.hoemann@hpe.com> <03b13d44-9ce3-ead8-020d-4b1b8114079d@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <03b13d44-9ce3-ead8-020d-4b1b8114079d@roeck-us.net> User-Agent: Mutt/1.9.1 (2017-09-22) 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 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. 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.) 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?) Thanks -- ----------------------------------------------------------------------------- Jerry Hoemann Software Engineer Hewlett Packard Enterprise -----------------------------------------------------------------------------