From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wcJ2444PRzDq5x for ; Tue, 30 May 2017 12:48:12 +1000 (AEST) Received: from ozlabs.org (ozlabs.org [103.22.144.67]) by bilbo.ozlabs.org (Postfix) with ESMTP id 3wcJ243KJ4z8svk for ; Tue, 30 May 2017 12:48:12 +1000 (AEST) Received: from mail-pf0-x243.google.com (mail-pf0-x243.google.com [IPv6:2607:f8b0:400e:c00::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3wcJ236l48z9s2P for ; Tue, 30 May 2017 12:48:11 +1000 (AEST) Received: by mail-pf0-x243.google.com with SMTP id n23so14607065pfb.3 for ; Mon, 29 May 2017 19:48:11 -0700 (PDT) Date: Tue, 30 May 2017 12:48:00 +1000 From: Balbir Singh To: Michael Ellerman Cc: linuxppc-dev@ozlabs.org, mikey@neuling.org, paulus@samba.org, npiggin@gmail.com Subject: Re: [PATCH] powerpc/64: Reclaim CPU_FTR_SUBCORE Message-ID: <20170530124800.11dbc61b@firefly.ozlabs.ibm.com> In-Reply-To: <1496022790-2017-1-git-send-email-mpe@ellerman.id.au> References: <1496022790-2017-1-git-send-email-mpe@ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 29 May 2017 11:53:10 +1000 Michael Ellerman wrote: > We are running low on CPU feature bits, so we only want to use them when > it's really necessary. > > CPU_FTR_SUBCORE is only used in one place, and only in C, so we don't > need it in order to make asm patching work. It can only be set on > "Power8" CPUs, which in practice means POWER8, POWER8E and POWER8NVL. > There are no plans to implement it on future CPUs, but if there ever > were we could retrofit it then. > > Although KVM uses subcores, it never looks at the CPU feature, it either > looks at the ISA level or the threads_per_subcore value. > > So drop the CPU feature and do a PVR check instead. Drop the device tree > "subcore" feature as we no longer support doing anything with it, and we > will drop it from skiboot too. > > Signed-off-by: Michael Ellerman > --- Acked-by: Balbir Singh I looked at CPU_FTR_DBELL and its used for initialization and in arch_show_interrupts(), no assembly it may be another candidate for reclaim Balbir Singh.