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=-18.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 67148C4346D for ; Thu, 6 Aug 2020 11:04:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5EE1F22D03 for ; Thu, 6 Aug 2020 11:04:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728410AbgHFHSQ (ORCPT ); Thu, 6 Aug 2020 03:18:16 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:8773 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727105AbgHFHSJ (ORCPT ); Thu, 6 Aug 2020 03:18:09 -0400 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 07FD0DE76A8B34F94D7E; Thu, 6 Aug 2020 15:18:03 +0800 (CST) Received: from [127.0.0.1] (10.174.186.173) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.487.0; Thu, 6 Aug 2020 15:17:59 +0800 Subject: Re: [PATCH] arm64: tlb: fix ARM64_TLB_RANGE with LLVM's integrated assembler To: Sami Tolvanen , Catalin Marinas , Will Deacon CC: Mark Rutland , Marc Zyngier , "Nick Desaulniers" , Nathan Chancellor , Kees Cook , , , References: <20200805181920.4013059-1-samitolvanen@google.com> From: Zhenyu Ye Message-ID: <95156879-d76e-65cc-1469-ae3096aa95e4@huawei.com> Date: Thu, 6 Aug 2020 15:17:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <20200805181920.4013059-1-samitolvanen@google.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.186.173] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 2020/8/6 2:19, Sami Tolvanen wrote: > Commit 7c78f67e9bd9 ("arm64: enable tlbi range instructions") breaks > LLVM's integrated assembler, because -Wa,-march is only passed to > external assemblers and therefore, the new instructions are not enabled > when IAS is used. > I have looked through the discussion on Github issues. The best way to solve this problem is try to pass the "-Wa,-march" parameter to clang even when IAS is enabled, which may need the cooperation of compilation tool chains :( Currently, I think we can solve the problem by passing the '-march=armv8.4-a' when using the integrated assembler, just like: diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 55bc8546d9c7..e5ce184e98c2 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -91,8 +91,12 @@ KBUILD_CFLAGS += $(branch-prot-flags-y) ifeq ($(CONFIG_AS_HAS_ARMV8_4), y) # make sure to pass the newest target architecture to -march. +ifneq ($(LLVM),) +KBUILD_CFLAGS += -march=armv8.4-a +else KBUILD_CFLAGS += -Wa,-march=armv8.4-a endif +endif ifeq ($(CONFIG_SHADOW_CALL_STACK), y) No need to worry about that this might generate instructions that are not supported on older hardware, because the 'TLB range' feature is only enabled when the hardware support ARMv8.4. > As binutils doesn't support .arch_extension tlb-rmi, this change adds > .arch armv8.4-a to __TLBI_0 and __TLBI_1 to fix the issue with both LLVM > IAS and binutils. > > Fixes: 7c78f67e9bd9 ("arm64: enable tlbi range instructions") > Link: https://github.com/ClangBuiltLinux/linux/issues/1106 > Signed-off-by: Sami Tolvanen Thanks, Zhenyu