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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0EE3C433F5 for ; Tue, 25 Jan 2022 02:21:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S3419902AbiAYCVa (ORCPT ); Mon, 24 Jan 2022 21:21:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S3415365AbiAYBpr (ORCPT ); Mon, 24 Jan 2022 20:45:47 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C65BC01D7C1; Mon, 24 Jan 2022 17:25:47 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E9EE561212; Tue, 25 Jan 2022 01:25:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCA3EC340E4; Tue, 25 Jan 2022 01:25:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643073943; bh=UqSazjT8UyPJQUEShMssyVrpCVBuSCCA0ELCO1ImzW0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nSPlo4OqUozVEIEmdVIKHI2ituuKy/T67z+vMSJCANyJDo1i9UEiHVgcXdaJoBb21 +IC0jCGd4z2K5cmdJUAkNCvBoTKpcxOvRb+O123AGD3pN8xGq8H0a/DQyblEniCliv gtH/07yXTnvS1+f83chvkucTrBmANoikqXruRDY3xfeTXVa03CP9CIWD/RsawFtVpo CqX9i6NOSAl076Tuw/3zvh8I5Snjvr6YUoXlCJ2Qra2fUcDiAn0NPIu/l6xnbMLcC6 JQWCGI2K9x6Y7d+/g8JDPyoXeHjCb3M4siP7I9HQ5el5tcKlyczpH+9l9gHSnduBps 48S3SKGI/lWOQ== Date: Mon, 24 Jan 2022 18:25:39 -0700 From: Nathan Chancellor To: Jiaxun Yang Cc: Nick Desaulniers , Thomas Bogendoerfer , Huacai Chen , "linux-mips@vger.kernel.org" , linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH 1/2] MIPS: Loongson64: Clean up use of cc-ifversion Message-ID: References: <20220120214001.1879469-1-nathan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Tue, Jan 25, 2022 at 12:03:32AM +0000, Jiaxun Yang wrote: > > > 在2022年1月24日一月 下午8:31，Nick Desaulniers写道： > > On Thu, Jan 20, 2022 at 1:40 PM Nathan Chancellor wrote: > >> > >> This Makefile checks that GCC is 4.9 or newer, which is redundant after > >> commit 76ae847497bc ("Documentation: raise minimum supported version of > >> GCC to 5.1"), so cc-option can be removed. > >> > >> Clang does not support -march=loongson3a so it needs to continue to use > >> -march=mips64r2, along with binutils less than 2.25, so check that both > >> GCC and binutils 2.25 or newer are being used before using > >> -march=loongson3a. These flags do not need to be checked with cc-option > >> anymore because all GCC versions support -march=loongson3a and > >> -march=mips64r2 and all clang versions support -march=mips64r2. > >> > >> Signed-off-by: Nathan Chancellor > > > > Thanks for the patch. I wonder why `_MIPS_ISA` only seems to be set at > > all for `-march=loongson3a` AFAICT, though that question is orthogonal > > to this patch. Perhaps the Loongson or MIPS maintainers know more? > > Otherwise seems like most uses of _MIPS_ISA can either be deleted or > > simplified now. > > This is because earlier GCC mistakenly set loongson3a to MIPS64 not MIPS64R2. > > But given that it's earlier than the minimal requirement GCC of kernel today, I think it should be safe to just move the whole logic. > > Thanks. So something like this (completely untested)? diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform index 3e660d6d3c2b..36ab2fe00835 100644 --- a/arch/mips/loongson64/Platform +++ b/arch/mips/loongson64/Platform @@ -5,24 +5,9 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap -# -# binutils from v2.25 on and gcc starting from v4.9.0 treat -march=loongson3a -# as MIPS64 R2; older versions as just R1. This leaves the possibility open -# that GCC might generate R2 code for -march=loongson3a which then is rejected -# by GAS. The cc-option can't probe for this behaviour so -march=loongson3a -# can't easily be used safely within the kbuild framework. -# -ifeq ($(call cc-ifversion, -ge, 0409, y), y) - ifeq ($(call ld-ifversion, -ge, 22500, y), y) - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) - else - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) - endif -else - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) +ifdef CONFIG_CPU_LOONGSON64 +cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2 +cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a endif # Some -march= flags enable MMI instructions, and GCC complains about that > > > > Reviewed-by: Nick Desaulniers > > > >> --- > >> arch/mips/loongson64/Platform | 13 +++---------- > >> 1 file changed, 3 insertions(+), 10 deletions(-) > >> > >> diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform > >> index 3e660d6d3c2b..981d3abc150e 100644 > >> --- a/arch/mips/loongson64/Platform > >> +++ b/arch/mips/loongson64/Platform > >> @@ -12,17 +12,10 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap > >> # by GAS. The cc-option can't probe for this behaviour so -march=loongson3a > >> # can't easily be used safely within the kbuild framework. > >> # > >> -ifeq ($(call cc-ifversion, -ge, 0409, y), y) > >> - ifeq ($(call ld-ifversion, -ge, 22500, y), y) > >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ > >> - $(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > >> - else > >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ > >> - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > >> - endif > >> +ifeq ($(CONFIG_CC_IS_GCC)$(call ld-ifversion, -ge, 22500, y), yy) > >> + cflags-$(CONFIG_CPU_LOONGSON64) += -march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64 > >> else > >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ > >> - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > >> + cflags-$(CONFIG_CPU_LOONGSON64) += -march=mips64r2 > >> endif > >> > >> # Some -march= flags enable MMI instructions, and GCC complains about that > >> > >> base-commit: 2c271fe77d52a0555161926c232cd5bc07178b39 > >> -- > >> 2.34.1 > >> > > > > > > -- > > Thanks, > > ~Nick Desaulniers > > -- > - Jiaxun