From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5B26241220; Tue, 5 Dec 2023 23:54:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nHW9ePkx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4668C433CD; Tue, 5 Dec 2023 23:54:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701820441; bh=A8sPnu2KKz5CALRbBlnZLQ9BA9ZLoGfN4oxpbkVxKs8=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=nHW9ePkxNxULIXpkQX7+3gpkoA53yAV+T5U/ICfkMgqE19v8jb/XiTgS3mpjAFz0X v1OMPQ2t+6qK9PGVZkOf4gl2YOhZCdid/wBQx/LzsxdgL9+MrlBsAvckjGZoxt5E+b gu2+Zkj6/N1RiQokIQOzlrI1+rblgQ7E5s7Ic8zl3bbIVqkJAfRGYy6D6eiY6bczFn hCDtIab1jNvW0l+TFFVyAjOIRl/CxrkEaLHhQIU9akBjUhXRLnEQGmtDizAnViuru+ SgHaskbGA27UV05tsksGLfMVIMdh2ulX7DG9Klt8Rrryb5N+5jCM1LYWC1OjMtuxys yrWuvjsjRXP6A== From: Nathan Chancellor Date: Tue, 05 Dec 2023 16:53:51 -0700 Subject: [PATCH v2 2/3] riscv: Restrict DWARF5 when building with LLVM to known working versions Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20231205-riscv-restrict-dwarf5-llvm-v2-2-aedf00a382ac@kernel.org> References: <20231205-riscv-restrict-dwarf5-llvm-v2-0-aedf00a382ac@kernel.org> In-Reply-To: <20231205-riscv-restrict-dwarf5-llvm-v2-0-aedf00a382ac@kernel.org> To: paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, conor@kernel.org Cc: maskray@google.com, ndesaulniers@google.com, linux-riscv@lists.infradead.org, llvm@lists.linux.dev, patches@lists.linux.dev, Nathan Chancellor X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=openpgp-sha256; l=2408; i=nathan@kernel.org; h=from:subject:message-id; bh=A8sPnu2KKz5CALRbBlnZLQ9BA9ZLoGfN4oxpbkVxKs8=; b=owGbwMvMwCUmm602sfCA1DTG02pJDKn5O8Q4P8XYPkypEL9XtmnWDum2KwU1x6S1uGoOWs2q4 mb5tjiuo5SFQYyLQVZMkaX6sepxQ8M5ZxlvnJoEM4eVCWQIAxenAEyk2p+R4UVQs57D9v0vnk7j kT5yIuFyrkZ25uH/wSvepxdtVGiRvc7I0HFz+uU7Pd7FV4SPr1z3TGUqX9v62D1eRQ0ViQueOMa tZQcA X-Developer-Key: i=nathan@kernel.org; a=openpgp; fpr=2437CB76E544CB6AB3D9DFD399739260CB6CB716 LLVM prior to 18.0.0 would generate incorrect debug info for DWARF5 due to linker relaxation, which was worked around in clang by defaulting RISC-V to DWARF4 [1]. Unfortunately, this workaround does not work for the kernel because the DWARF version can be independently changed from the default in Kconfig. Do not allow DWARF5 to be selected for RISC-V when using linker relaxation (ld.lld >= 15.0.0) and a version of LLVM that does not have the fixes (the integrated assembler [2] and ld.lld [3] < 18.0.0) necessary to generate the correct debug info. Link: https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6 [1] Link: https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a [2] Link: https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77 [3] Signed-off-by: Nathan Chancellor --- arch/riscv/Kconfig | 9 +++++++++ lib/Kconfig.debug | 1 + 2 files changed, 10 insertions(+) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 72be1d8122a3..81b473cb47b0 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -186,6 +186,15 @@ config RISCV_USE_LINKER_RELAXATION # https://github.com/llvm/llvm-project/commit/6611d58f5bbcbec77262d392e2923e1d680f6985 depends on !LD_IS_LLD || LLD_VERSION >= 150000 +# https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6 +config ARCH_HAS_BROKEN_DWARF5 + def_bool y + depends on RISCV_USE_LINKER_RELAXATION + # https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a + depends on AS_IS_LLVM && AS_VERSION < 180000 + # https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77 + depends on LD_IS_LLD && LLD_VERSION < 180000 + config ARCH_MMAP_RND_BITS_MIN default 18 if 64BIT default 8 diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index cc7d53d9dc01..a0ebce05a368 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -282,6 +282,7 @@ config DEBUG_INFO_DWARF4 config DEBUG_INFO_DWARF5 bool "Generate DWARF Version 5 debuginfo" select DEBUG_INFO + depends on !ARCH_HAS_BROKEN_DWARF5 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) help Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc -- 2.43.0