From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp05.in.ibm.com (e28smtp05.in.ibm.com [122.248.162.5]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp05.in.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 9DF362C00E8 for ; Mon, 15 Jul 2013 16:03:32 +1000 (EST) Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 15 Jul 2013 11:27:55 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 2B485E0055 for ; Mon, 15 Jul 2013 11:33:17 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r6F63LWu33095702 for ; Mon, 15 Jul 2013 11:33:22 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r6F63MGH032374 for ; Mon, 15 Jul 2013 16:03:24 +1000 From: "Aneesh Kumar K.V" To: Scott Wood , Benjamin Herrenschmidt Subject: Re: [PATCH] powerpc/fsl-booke: Work around erratum A-006958 In-Reply-To: <1373677412-24329-1-git-send-email-scottwood@freescale.com> References: <1373677412-24329-1-git-send-email-scottwood@freescale.com> Date: Mon, 15 Jul 2013 11:33:22 +0530 Message-ID: <87mwpojr6d.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain Cc: Scott Wood , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Scott Wood writes: > diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype > index ae0aaea..7f0e2e5 100644 > --- a/arch/powerpc/platforms/Kconfig.cputype > +++ b/arch/powerpc/platforms/Kconfig.cputype > @@ -165,6 +165,17 @@ config PPC_E500MC > such as e5500/e6500), and must be disabled for running on > e500v1 or e500v2. > > +config FSL_ERRATUM_A_006958 > + bool > + depends on PPC_E500MC && PPC64 > + default y > + help > + Workaround for erratum A-006958, which says that 64-bit > + timebase reads are not atomic. The workaround is to fall back > + to the 32-bit method of reading timebase. Note that timebase > + is readable by userspace, so any non-vdso userspace accesses > + will need to have the workaround applied separately. > + > config PPC_FPU > bool > default y if PPC64 I am completely new to this area, so ignore if it is silly. But how do we expect to select this config ? Should that happen via .config ? That seems strange, because without this change some of the configs will surely be broken/buggy right ?. I was expecting it not be a config entry, primarily because I haven't seem something similar on other archs. And if there is an erratum against a cpu release, we should by default apply this when we know we are running on those cpus right ? Which implies this should not be a config option ? -aneesh