From nobody Tue Dec 16 11:42:56 2025 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 B6184C32772 for ; Fri, 19 Aug 2022 16:42:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353557AbiHSQmZ (ORCPT ); Fri, 19 Aug 2022 12:42:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40032 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353569AbiHSQkC (ORCPT ); Fri, 19 Aug 2022 12:40:02 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7FC8107DA7; Fri, 19 Aug 2022 09:08:40 -0700 (PDT) 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 ams.source.kernel.org (Postfix) with ESMTPS id 0BECCB8281A; Fri, 19 Aug 2022 16:07:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 428DDC43470; Fri, 19 Aug 2022 16:07:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660925261; bh=edBzfxKF2CtnaaPIFtuLy8Zc8zyI8zFq4FhY4N0gyYo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XmDq2mUGN2irhKIixPBSwXa/FeXO6pqVOuL/fEzcgJiKDZUZIQRh2IZ6f8m2GPpRj Xyd+R9a17HVuco/s4cLbhHMPqCrCMP8A8V9yly1zBIc0yjJ5Vbxq8JBAnzUpzelDbR x8sjwjm4Hbwq7fCIOtfm7zpgrjzrS0alLH4ZFESw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrea Righi , Ingo Molnar , Sasha Levin Subject: [PATCH 5.10 435/545] x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y Date: Fri, 19 Aug 2022 17:43:25 +0200 Message-Id: <20220819153848.879857019@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220819153829.135562864@linuxfoundation.org> References: <20220819153829.135562864@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Andrea Righi [ Upstream commit de979c83574abf6e78f3fa65b716515c91b2613d ] With CONFIG_PREEMPTION disabled, arch/x86/entry/thunk_$(BITS).o becomes an empty object file. With some old versions of binutils (i.e., 2.35.90.20210113-1ubuntu1) the GNU assembler doesn't generate a symbol table for empty object files and objtool fails with the following error when a valid symbol table cannot be found: arch/x86/entry/thunk_64.o: warning: objtool: missing symbol table To prevent this from happening, build thunk_$(BITS).o only if CONFIG_PREEMPTION is enabled. BugLink: https://bugs.launchpad.net/bugs/1911359 Fixes: 320100a5ffe5 ("x86/entry: Remove the TRACE_IRQS cruft") Signed-off-by: Andrea Righi Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/Ys/Ke7EWjcX+ZlXO@arighi-desktop Signed-off-by: Sasha Levin --- arch/x86/entry/Makefile | 3 ++- arch/x86/entry/thunk_32.S | 2 -- arch/x86/entry/thunk_64.S | 4 ---- arch/x86/um/Makefile | 3 ++- 4 files changed, 4 insertions(+), 8 deletions(-) diff --git a/arch/x86/entry/Makefile b/arch/x86/entry/Makefile index 58533752efab..63dc4b1dfc92 100644 --- a/arch/x86/entry/Makefile +++ b/arch/x86/entry/Makefile @@ -21,12 +21,13 @@ CFLAGS_syscall_64.o +=3D $(call cc-option,-Wno-overrid= e-init,) CFLAGS_syscall_32.o +=3D $(call cc-option,-Wno-override-init,) CFLAGS_syscall_x32.o +=3D $(call cc-option,-Wno-override-init,) =20 -obj-y :=3D entry.o entry_$(BITS).o thunk_$(BITS).o syscall_$(BITS).o +obj-y :=3D entry.o entry_$(BITS).o syscall_$(BITS).o obj-y +=3D common.o =20 obj-y +=3D vdso/ obj-y +=3D vsyscall/ =20 +obj-$(CONFIG_PREEMPTION) +=3D thunk_$(BITS).o obj-$(CONFIG_IA32_EMULATION) +=3D entry_64_compat.o syscall_32.o obj-$(CONFIG_X86_X32_ABI) +=3D syscall_x32.o =20 diff --git a/arch/x86/entry/thunk_32.S b/arch/x86/entry/thunk_32.S index 7591bab060f7..ff6e7003da97 100644 --- a/arch/x86/entry/thunk_32.S +++ b/arch/x86/entry/thunk_32.S @@ -29,10 +29,8 @@ SYM_CODE_START_NOALIGN(\name) SYM_CODE_END(\name) .endm =20 -#ifdef CONFIG_PREEMPTION THUNK preempt_schedule_thunk, preempt_schedule THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace EXPORT_SYMBOL(preempt_schedule_thunk) EXPORT_SYMBOL(preempt_schedule_notrace_thunk) -#endif =20 diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S index 1b5044ad8cd0..14776163fbff 100644 --- a/arch/x86/entry/thunk_64.S +++ b/arch/x86/entry/thunk_64.S @@ -36,14 +36,11 @@ SYM_FUNC_END(\name) _ASM_NOKPROBE(\name) .endm =20 -#ifdef CONFIG_PREEMPTION THUNK preempt_schedule_thunk, preempt_schedule THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace EXPORT_SYMBOL(preempt_schedule_thunk) EXPORT_SYMBOL(preempt_schedule_notrace_thunk) -#endif =20 -#ifdef CONFIG_PREEMPTION SYM_CODE_START_LOCAL_NOALIGN(__thunk_restore) popq %r11 popq %r10 @@ -58,4 +55,3 @@ SYM_CODE_START_LOCAL_NOALIGN(__thunk_restore) RET _ASM_NOKPROBE(__thunk_restore) SYM_CODE_END(__thunk_restore) -#endif diff --git a/arch/x86/um/Makefile b/arch/x86/um/Makefile index 77f70b969d14..3113800da63a 100644 --- a/arch/x86/um/Makefile +++ b/arch/x86/um/Makefile @@ -27,7 +27,8 @@ else =20 obj-y +=3D syscalls_64.o vdso/ =20 -subarch-y =3D ../lib/csum-partial_64.o ../lib/memcpy_64.o ../entry/thunk_6= 4.o +subarch-y =3D ../lib/csum-partial_64.o ../lib/memcpy_64.o +subarch-$(CONFIG_PREEMPTION) +=3D ../entry/thunk_64.o =20 endif =20 --=20 2.35.1