From patchwork Thu Sep 9 07:42:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Li X-Patchwork-Id: 12482607 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_GIT 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 78175C433EF for ; Thu, 9 Sep 2021 07:42:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5137560F11 for ; Thu, 9 Sep 2021 07:42:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242958AbhIIHoC (ORCPT ); Thu, 9 Sep 2021 03:44:02 -0400 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:51510 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232549AbhIIHoC (ORCPT ); Thu, 9 Sep 2021 03:44:02 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R351e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=ashimida@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0UnmHPCV_1631173364; Received: from localhost(mailfrom:ashimida@linux.alibaba.com fp:SMTPD_---0UnmHPCV_1631173364) by smtp.aliyun-inc.com(127.0.0.1); Thu, 09 Sep 2021 15:42:51 +0800 From: ashimida To: masahiroy@kernel.org, michal.lkml@markovi.net, nathan@kernel.org, ndesaulniers@google.com Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, ashimida Subject: [PATCH] [RFC] kbuild: add CLANG_TRIPLE to prevent clang from compiling with wrong --target Date: Thu, 9 Sep 2021 15:42:43 +0800 Message-Id: <1631173363-40160-1-git-send-email-ashimida@linux.alibaba.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Kernel compiled with tool chain CROSS_COMPILE=aarch64-linux-android- will panic during the startup phase. Clang's --target option comes from $(CROSS_COMPILE). At the time -fstack-protector-strong is enabled, and compiled with command: make CC=clang HOSTCC=clang ARCH=arm64 CROSS_COMPILE=aarch64-linux-android- clang will insert code like: mrs x8, TPIDR_EL0 //default value is zero str x8, [sp] ldr x8, [x8, #40] //access addr 0x40 instead of the code that accesses __stack_chk_guard to get the canary, which will cause the kernel to crash due to 0x40 address access. This patch (from android) is used to remind the user that current tool chain cannot be used as the "--target" of clang, the user should specify an additional "--target" through CLANG_TRIPLE. Signed-off-by: ashimida --- Makefile | 6 +++++- scripts/clang-android.sh | 4 ++++ 2 files changed, 9 insertions(+), 1 deletion(-) create mode 100755 scripts/clang-android.sh diff --git a/Makefile b/Makefile index 61741e9..09bb314 100644 --- a/Makefile +++ b/Makefile @@ -586,7 +586,11 @@ CC_VERSION_TEXT = $(subst $(pound),,$(shell $(CC) --version 2>/dev/null | head - ifneq ($(findstring clang,$(CC_VERSION_TEXT)),) ifneq ($(CROSS_COMPILE),) -CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) +CLANG_TRIPLE ?= $(CROSS_COMPILE) +CLANG_FLAGS += --target=$(notdir $(CLANG_TRIPLE:%-=%)) +ifeq ($(shell $(srctree)/scripts/clang-android.sh $(CC) $(CLANG_FLAGS)), y) +$(error "Clang with Android --target detected. Did you specify CLANG_TRIPLE?") +endif endif ifeq ($(LLVM_IAS),1) CLANG_FLAGS += -integrated-as diff --git a/scripts/clang-android.sh b/scripts/clang-android.sh new file mode 100755 index 0000000..9186c4f --- /dev/null +++ b/scripts/clang-android.sh @@ -0,0 +1,4 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +$* -dM -E - &1 | grep -q __ANDROID__ && echo "y"