From nobody Fri Dec 19 18:43:11 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 14D1BC433FE for ; Sat, 22 Oct 2022 08:50:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234931AbiJVIup (ORCPT ); Sat, 22 Oct 2022 04:50:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235094AbiJVItf (ORCPT ); Sat, 22 Oct 2022 04:49:35 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D70CD28C318; Sat, 22 Oct 2022 01:10:59 -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 813E9B82E0C; Sat, 22 Oct 2022 08:08:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF247C433D7; Sat, 22 Oct 2022 08:08:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666426081; bh=QexgGbePdpSUxSJVDrDa2mgDst0/2mVL7ZvWwc9hdg0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M74X4bZyZuggXw6RsyOJBxG+/4oh3fDNYP81PyjBDHT/Sxsu9MmVoyNqSpx1IrMqM IG5v/3q/6hPAYw4m5OCWgZ3/NzJ4N0sdMFXs2mZP5XSxfTL4ciSwSI0PcLvEPDyyG6 czfF34bD1WVQ28vMRYTH8ZH5eStvdrNioU6H+Jvc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Masahiro Yamada Subject: [PATCH 5.19 712/717] lib/Kconfig.debug: Add check for non-constant .{s,u}leb128 support to DWARF5 Date: Sat, 22 Oct 2022 09:29:51 +0200 Message-Id: <20221022072529.954572792@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221022072415.034382448@linuxfoundation.org> References: <20221022072415.034382448@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: Nathan Chancellor commit 0a6de78cff600cb991f2a1b7ed376935871796a0 upstream. When building with a RISC-V kernel with DWARF5 debug info using clang and the GNU assembler, several instances of the following error appear: /tmp/vgettimeofday-48aa35.s:2963: Error: non-constant .uleb128 is not sup= ported Dumping the .s file reveals these .uleb128 directives come from .debug_loc and .debug_ranges: .Ldebug_loc0: .byte 4 # DW_LLE_offset_pair .uleb128 .Lfunc_begin0-.Lfunc_begin0 # starting offset .uleb128 .Ltmp1-.Lfunc_begin0 # ending offset .byte 1 # Loc expr size .byte 90 # DW_OP_reg10 .byte 0 # DW_LLE_end_of_list .Ldebug_ranges0: .byte 4 # DW_RLE_offset_pair .uleb128 .Ltmp6-.Lfunc_begin0 # starting offset .uleb128 .Ltmp27-.Lfunc_begin0 # ending offset .byte 4 # DW_RLE_offset_pair .uleb128 .Ltmp28-.Lfunc_begin0 # starting offset .uleb128 .Ltmp30-.Lfunc_begin0 # ending offset .byte 0 # DW_RLE_end_of_list There is an outstanding binutils issue to support a non-constant operand to .sleb128 and .uleb128 in GAS for RISC-V but there does not appear to be any movement on it, due to concerns over how it would work with linker relaxation. To avoid these build errors, prevent DWARF5 from being selected when using clang and an assembler that does not have support for these symbol deltas, which can be easily checked in Kconfig with as-instr plus the small test program from the dwz test suite from the binutils issue. Link: https://sourceware.org/bugzilla/show_bug.cgi?id=3D27215 Link: https://github.com/ClangBuiltLinux/linux/issues/1719 Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman --- lib/Kconfig.debug | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -231,6 +231,11 @@ config DEBUG_INFO in the "Debug information" choice below, indicating that debug information will be generated for build targets. =20 +# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, = which +# some targets may not support: https://sourceware.org/bugzilla/show_bug.c= gi?id=3D27215 +config AS_HAS_NON_CONST_LEB128 + def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\= n.Lexpr_end4:) + choice prompt "Debug information" depends on DEBUG_KERNEL @@ -253,7 +258,7 @@ config DEBUG_INFO_NONE config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT bool "Rely on the toolchain's implicit default DWARF version" select DEBUG_INFO - depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS= _GNU && AS_VERSION >=3D 23502) + depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS= _GNU && AS_VERSION >=3D 23502 && AS_HAS_NON_CONST_LEB128) help The implicit default version of DWARF debug info produced by a toolchain changes over time. @@ -277,7 +282,7 @@ config DEBUG_INFO_DWARF4 config DEBUG_INFO_DWARF5 bool "Generate DWARF Version 5 debuginfo" select DEBUG_INFO - depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >=3D 23= 502) + depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >=3D 23= 502 && AS_HAS_NON_CONST_LEB128) help Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 5.0+ accepts the -gdwarf-5 flag but only had partial support for some