From patchwork Tue May 18 19:01:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 441773 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=-24.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS, 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 D5BDEC433B4 for ; Tue, 18 May 2021 19:01:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8FEC60FE9 for ; Tue, 18 May 2021 19:01:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238448AbhERTCz (ORCPT ); Tue, 18 May 2021 15:02:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:49546 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238394AbhERTCy (ORCPT ); Tue, 18 May 2021 15:02:54 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2366A610E9; Tue, 18 May 2021 19:01:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621364496; bh=N0OYIBjgObbNxtkzADopyy7cdON09mSWl+anyWhDbPY=; h=From:To:Cc:Subject:Date:From; b=gAFZkQUMSOAp5Jd8+egXCbE2xH9HSMjlQjU4nYmhViIMjmP0GMe9puxRUWa7Id5mV 3moE5aBfcMOSIXcEtGhsN33EqnWqtR2PEAZR+DamRe+YeYEvPUxcENh0q8suB9quBG OtLwRbKe+Sf61sz1oXjMfdypCgo2SWvOc4GxUPaYLNzp/uGal7uq2Zy95SgpahR6NZ e4L2q3tWdJbDyIUQVS8LOcMyqyHff9sIMTCdI2kstKfLn1KigvWxNB8gAtwKssiBNI 7df59rgE1xBR7jywcHEeoI+uB1L+jrccfmIRVyZpmv8/xh3W4OzLn/ypgrdMThMcEJ RDUCMjezTv0iA== From: Nathan Chancellor To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Kees Cook , Sami Tolvanen , Nick Desaulniers Cc: "H. Peter Anvin" , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nathan Chancellor , stable@vger.kernel.org, Anthony Ruhier Subject: [PATCH] x86: Fix location of '-plugin-opt=' flags Date: Tue, 18 May 2021 12:01:06 -0700 Message-Id: <20210518190106.60935-1-nathan@kernel.org> X-Mailer: git-send-email 2.32.0.rc0 MIME-Version: 1.0 X-Patchwork-Bot: notify Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Commit b33fff07e3e3 ("x86, build: allow LTO to be selected") added a couple of '-plugin-opt=' flags to KBUILD_LDFLAGS because the code model and stack alignment are not stored in LLVM bitcode. However, these flags were added to KBUILD_LDFLAGS prior to the emulation flag assignment, which uses ':=', so they were overwritten and never added to $(LD) invocations. The absence of these flags caused misalignment issues in the AMDGPU driver when compiling with CONFIG_LTO_CLANG, resulting in general protection faults. Shuffle the assignment below the initial one so that the flags are properly passed along and all of the linker flags stay together. At the same time, avoid any future issues with clobbering flags by changing the emulation flag assignment to '+=' since KBUILD_LDFLAGS is already defined with ':=' in the main Makefile before being exported for modification here as a result of commit ce99d0bf312d ("kbuild: clear LDFLAGS in the top Makefile"). Cc: stable@vger.kernel.org Fixes: b33fff07e3e3 ("x86, build: allow LTO to be selected") Link: https://github.com/ClangBuiltLinux/linux/issues/1374 Reported-by: Anthony Ruhier Tested-by: Anthony Ruhier Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers --- arch/x86/Makefile | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) base-commit: d07f6ca923ea0927a1024dfccafc5b53b61cfecc diff --git a/arch/x86/Makefile b/arch/x86/Makefile index c77c5d8a7b3e..307529417021 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -178,11 +178,6 @@ ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) endif -ifdef CONFIG_LTO_CLANG -KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \ - -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8) -endif - # Workaround for a gcc prelease that unfortunately was shipped in a suse release KBUILD_CFLAGS += -Wno-sign-compare # @@ -202,7 +197,12 @@ ifdef CONFIG_RETPOLINE endif endif -KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE) +KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) + +ifdef CONFIG_LTO_CLANG +KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \ + -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8) +endif ifdef CONFIG_X86_NEED_RELOCS LDFLAGS_vmlinux := --emit-relocs --discard-none