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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30B74C2BA2B for ; Mon, 13 Apr 2020 19:26:34 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0B53920735 for ; Mon, 13 Apr 2020 19:26:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="EpyvWvBB"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="pCeStENd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B53920735 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SBHaOAwwGP7EUaon3k8RLsEsDBcmpP+YlUtsk/gF+8g=; b=EpyvWvBBWzXpqs lwWxoGcXUjP85Hs0i+8TieMOAT7NHleSQBr1ykhwuAlICS9+NeV746pc7zhNZgx0JRS6ThP7aBwqx 4/Jk2dHiXQtH7+GA9WU4W5UizfSJqpqW9/CpZ7EX88N7TF4X8C7XQ3rsVC6jxcFGHC0kZonuEKDPq 433xr/dIX+jYVgZDPlPQHazO2iaVZ47rga+k0EqBto28x7mCNCv3kdHNbZJ0rCSE/Xo1umcaPQNPO tyi4reKbW8/7r8fIofhbo/LrcXHInDZfYh8PK+AO5uqGMk/eot2dkakmH+vTDLu2ShxFHt+R6FGLA 0EoNiDycRW794EHa+xOw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jO4j2-0004lk-Qd; Mon, 13 Apr 2020 19:26:32 +0000 Received: from mail-pf1-x444.google.com ([2607:f8b0:4864:20::444]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jO4iz-0004kd-Du for linux-arm-kernel@lists.infradead.org; Mon, 13 Apr 2020 19:26:30 +0000 Received: by mail-pf1-x444.google.com with SMTP id l1so4950196pff.10 for ; Mon, 13 Apr 2020 12:26:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=KdK0zPwtveoXwIU/pJ0It4FhLQkN9xabxjzAbXM7HUg=; b=pCeStENdG/6hj1L+u+cxwBd+lxmKze8JFGF8eG5T6Rojz3ubtHvutlqKjh1KPf6A1O aVJALpWYIoX41Wh69ZxBMS5ZrlWERrkzwlEgCrDO/r+22JmIYx76G5gf1ZTL97p90L07 RaKonfqiZWxrjLkWbK3up26Zr9TpJVztjD7fmUypSnBONt4CK8hKMTgKAlUz4vTqWPR9 m1vmfM8NjyP7tp1Wr6BPswfx8rXp27YDEOmnMAHKaw2g6gy0HL1RmN/M2oftUt8BZq+N xfxfpd+p8cC/w61Ukhm/QDEtNS9d35nxOgPWvBQrgI3bs8FgJwfqoHaCQNESYpmQj60s LIBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=KdK0zPwtveoXwIU/pJ0It4FhLQkN9xabxjzAbXM7HUg=; b=pe3hQr5xfrBsZ62kWyI/82/ynT8u9ezA4VCVrm+KYHUJoh8L5mtrWjm7Jk34Vcd1eP NRinFTvbi6yVhKkRIM5rLJw7MAGDSaMeFQetFIpR66kbhrFzre0l53rdxZpoMRcXiYQj UiXtc4RO1ldgfAZSNYNFX9vHsyg/ZbPBm8hZap50m8tgC5svCe/A3i3CHN9Qbao7J81b /4m4hV1sRO571/gx/KgtDAqsRH2HRCWh5OqvHZa6R9bpQGFmczt4FS+raayXWuMLshE8 sfrA/L9hqkMz9lARBKGwLWGVlBQ84WUx5GF4ttZlT55G0Ysnp/EC7XiSr7LdlMZ9Lks/ fnlQ== X-Gm-Message-State: AGi0PuZsxt4e28+RR0ipVsxceE/ab3K4O2ODNNTfo+hsP7ct9yjdFVvA LUwbP60WVkcvKKrYM5AU+8RAzDZY9mT/9WlYHhrYoA== X-Google-Smtp-Source: APiQypIUhqWcYiDcyMcc+YPUUWgJ1hH3x1WwMExIHnVSN2oF/LeLDnug09prydJRjw+z6TLAVtOg78Y4PPWpvE+OoMg= X-Received: by 2002:a63:6546:: with SMTP id z67mr6229011pgb.10.1586805988175; Mon, 13 Apr 2020 12:26:28 -0700 (PDT) MIME-Version: 1.0 References: <20200409232728.231527-1-caij2003@gmail.com> <20200410165948.GD448831@lunn.ch> <20200410183420.GE25745@shell.armlinux.org.uk> In-Reply-To: <20200410183420.GE25745@shell.armlinux.org.uk> From: Nick Desaulniers Date: Mon, 13 Apr 2020 12:26:16 -0700 Message-ID: Subject: Re: [PATCH] ARM: do not assemble iwmmxt.S with LLVM toolchain To: Russell King - ARM Linux admin X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200413_122629_491319_E672BD48 X-CRM114-Status: GOOD ( 20.19 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Lunn , Linus Walleij , Peter Smith , Stefan Agner , David Howells , Mauro Carvalho Chehab , Manoj Gupta , Benjamin Gaignard , "Joel Fernandes \(Google\)" , Jian Cai , Bartosz Golaszewski , Ilie Halip , Masahiro Yamada , Krzysztof Kozlowski , clang-built-linux , Sami Tolvanen , Masami Hiramatsu , Arnd Bergmann , "Steven Rostedt \(VMware\)" , Jian Cai , Doug Anderson , Dan Williams , Linux ARM , Greg Kroah-Hartman , LKML , Patrick Bellasi , "Eric W. Biederman" , Tejun Heo , Andrew Morton Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Apr 10, 2020 at 11:34 AM Russell King - ARM Linux admin wrote: > > On Fri, Apr 10, 2020 at 06:59:48PM +0200, Andrew Lunn wrote: > > On Thu, Apr 09, 2020 at 04:27:26PM -0700, Jian Cai wrote: > > > iwmmxt.S contains XScale instructions > > > > Dumb question.... > > > > Are these Xscale instructions? My understanding is that they are an > > instruction set of their own, implementing something similar to IA-32 > > MMX. > > > > Would it be more accurate to say CLANG does not support the iwmmxt > > instruction set? > > Yes, because the XScale core on its own (otherwise known as 80200) > doesn't support iWMMXT. > > It's worth pointing out that the iWMMXT instruction set uses the > co-processor #1 instruction space as defined by the ARMv5 ARM ARM, > which is also the FPA (floating point accelerator) instruction > space - which is the FP instruction set prior to VFP. Reusing instruction encoding space? :-X I'll have to look and see how we define cases like this in LLVM. > > The LDFP and similar instructions that binutils decodes the opcodes > as are FPA instructions, and the LDC2 instructions are their "generic > co-processor" versions where there's no FPA instruction that matches > the op-code. > > I'll also point out that the reason the iWMMXT code has never been > ported to Thumb2 is because there are no equivalents for the > co-processor instructions in the Thumb2 instruction set defined in > ARMv5. Hence why the file has a .arm. So, the fact the file hasn't > changed for a long time and hasn't been updated with "improvements" > such as Thumb2 kernels is because that's completely irrelevent to > the ISA. > > It is an example of code that has become stable and mature, and > requires no maintanence with GNU toolchains. I agree. I think this is something we can mark broken for our toolchain in Kconfig for the time being, and revisit once we have more resources to implement (leaving the sources as is). -- Thanks, ~Nick Desaulniers _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel