From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:55866 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727045AbeKZVri (ORCPT ); Mon, 26 Nov 2018 16:47:38 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Behan Webster , =?UTF-8?q?Jan-Simon=20M=C3=B6ller?= , Mark Charlebois , Greg Hackmann , Matthias Kaehlcke , Masahiro Yamada , Nathan Chancellor Subject: [PATCH 4.4 06/70] kbuild: Add better clang cross build support Date: Mon, 26 Nov 2018 11:50:21 +0100 Message-Id: <20181126105047.521454664@linuxfoundation.org> In-Reply-To: <20181126105046.722096341@linuxfoundation.org> References: <20181126105046.722096341@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Behan Webster commit 785f11aa595bc3d4e74096cbd598ada54ecc0d81 upstream. Add cross target to CC if using clang. Also add custom gcc toolchain path for fallback gcc tools. Clang will fallback to using things like ld, as, and libgcc if (respectively) one of the llvm linkers isn't available, the integrated assembler is turned off, or an appropriately cross-compiled version of compiler-rt isn't available. To this end, you can specify the path to this fallback gcc toolchain with GCC_TOOLCHAIN. Signed-off-by: Behan Webster Reviewed-by: Jan-Simon Möller Reviewed-by: Mark Charlebois Signed-off-by: Greg Hackmann Signed-off-by: Matthias Kaehlcke Signed-off-by: Masahiro Yamada Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman --- Makefile | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/Makefile +++ b/Makefile @@ -698,6 +698,15 @@ endif KBUILD_CFLAGS += $(stackp-flag) ifeq ($(cc-name),clang) +ifneq ($(CROSS_COMPILE),) +CLANG_TARGET := -target $(notdir $(CROSS_COMPILE:%-=%)) +GCC_TOOLCHAIN := $(realpath $(dir $(shell which $(LD)))/..) +endif +ifneq ($(GCC_TOOLCHAIN),) +CLANG_GCC_TC := -gcc-toolchain $(GCC_TOOLCHAIN) +endif +KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) +KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,) KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,) KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)