From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9E80AC433FE for ; Thu, 6 Oct 2022 21:57:14 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Mk4zY179Dz3dsC for ; Fri, 7 Oct 2022 08:57:13 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20210112 header.b=JiMSB/Aa; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::62c; helo=mail-pl1-x62c.google.com; envelope-from=npiggin@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20210112 header.b=JiMSB/Aa; dkim-atps=neutral Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Mk4yT54mjz2xZ7 for ; Fri, 7 Oct 2022 08:56:16 +1100 (AEDT) Received: by mail-pl1-x62c.google.com with SMTP id l4so2895613plb.8 for ; Thu, 06 Oct 2022 14:56:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-transfer-encoding:mime-version:from:to:cc:subject:date; bh=xLUB0E3LfbszQ4qFdgdItsy+sBeI19HoAo47UM2h3l8=; b=JiMSB/AaGi1Dt/0zATolvZ1MmhfJAuWSjFSVI8AlOkb8LoebaB3hZVTn21zom8DgpM gDnkAR2oeHzdji9F9Sy11Gkuw//FMLmLSoEaNCYQiYiAVED1jws7Ejnz+vnK+SbUmuq9 FsxQvCkteG6HZ9ZwWzu30ooP7z+Jwbi9wPi8d9Ng/TGiPdRi3sf1otj0yakGqxYAfL3R 3YulMz7vY2bi3h99Oqc1VPV/FvLgTQJg1ucdviCXNBJleoeU2GEud4R/cjoY4svlmWfJ wS0Qm+7+b4JWDFf2ySoA+IugHSraouxRIIM5zaWe1hlqu+6NPBD4j9R0t0E7xC7RkkwL KXYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-transfer-encoding:mime-version:x-gm-message-state:from:to :cc:subject:date; bh=xLUB0E3LfbszQ4qFdgdItsy+sBeI19HoAo47UM2h3l8=; b=rLK13TpE9FzLa7cyP1z7jCL+a6Ie3zUYndHHq2whNAHqHv3+5cVfYhD38wpSAd+ypY uz/CgiNyeEjRHwtH4dkuoq8wNmGhaF3cFztswaU0Yksgty7MSWC7xB3OK/QZB7mfSGqt +AmZ9lb+yzXA+pToseNnDbTExj6kXrpl2TzN7fOZ2o0A3+ZhRMadRf5vruVChgAbjwol SuEDvsTjRP5qii+8ab08zregD3Py2T5jMODJaTrSyL+4JxB3bdZLNq8PDxlIPLsTGjyd cvTAvOqj2ZAs+fv4a80yBIS4G1Ae7CTwkFWzZMlUA8jZf3j2Da36Mmue7nrY/e7iWUL6 5g2w== X-Gm-Message-State: ACrzQf0MH6/Y1T4nm/RmN0Vauyuhdhvc2OO78gzGVZYxgBYYXWRo/GB6 cxYP62vYKcM5hkTR2sEK2fMuoiZGcwE= X-Google-Smtp-Source: AMsMyM7vBb8O9rXHs7a1gyj4sFwjyzTgCrI/WWuUSPkeD/vL5w++NDcxENhVgN5lAlaGyw6n2Ixi4g== X-Received: by 2002:a17:90a:4888:b0:203:6d42:ccae with SMTP id b8-20020a17090a488800b002036d42ccaemr1819174pjh.166.1665093374936; Thu, 06 Oct 2022 14:56:14 -0700 (PDT) Received: from localhost ([118.208.156.99]) by smtp.gmail.com with ESMTPSA id l14-20020a170903120e00b0017f74cab9eesm96586plh.128.2022.10.06.14.56.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Oct 2022 14:56:13 -0700 (PDT) Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Fri, 07 Oct 2022 07:56:09 +1000 Message-Id: Subject: Re: [PATCH] powerpc/64s: POWER10 CPU Kconfig build option From: "Nicholas Piggin" To: "Segher Boessenkool" X-Mailer: aerc 0.11.0 References: <20220923033004.536127-1-npiggin@gmail.com> <20221006195411.GS25951@gate.crashing.org> In-Reply-To: <20221006195411.GS25951@gate.crashing.org> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri Oct 7, 2022 at 5:54 AM AEST, Segher Boessenkool wrote: > Hi! > > On Fri, Sep 23, 2022 at 01:30:04PM +1000, Nicholas Piggin wrote: > > This adds basic POWER10_CPU option, which builds with -mcpu=3Dpower10. > > > +# No prefix or pcrel > > +KBUILD_CFLAGS +=3D $(call cc-option,-mno-prefixed) > > +KBUILD_CFLAGS +=3D $(call cc-option,-mno-pcrel) > > Why do you disable all prefixed insns? What goes wrong if you don't? Potentially things like kprobes. > Same question for pcrel. I'm sure you want to optimise it better, but > it's not clear to me how it fails now? For pcrel addressing? Bootstrapping the C environment is one, the module dynamic linker is another. Some details in this series. https://lists.ozlabs.org/pipermail/linuxppc-dev/2022-September/248521.html > > Please say in the comment what is wrong, don't spread fear :-) > > > +# No AltiVec or VSX or MMA instructions when building kernel > > KBUILD_CFLAGS +=3D $(call cc-option,-mno-altivec) > > KBUILD_CFLAGS +=3D $(call cc-option,-mno-vsx) > > +KBUILD_CFLAGS +=3D $(call cc-option,-mno-mma) > > MMA code is never generated unless the code asks for it explicitly. > This is fundamental, not just an implementations side effect. Well, now it double won't be generated :) Thanks, Nick