From patchwork Wed May 22 11:47:55 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 13670814 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 0CC3413D527; Wed, 22 May 2024 11:48:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716378491; cv=none; b=D9MoFM5P2xfmdbT26RKXh9066TJhzqRgz5mfd4XmKEbGgp0lIKn0/CA4ZonW4ihTsOpjChUouihuQrSxvEo6eN5Vq1qFTiVfPRylxQfxL81sK7WuqmrRxWHsBExM6EbnTY3BZn+TwsUT7/SvFcAZhvC09woxeQR5J0vnlD3ZMkE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716378491; c=relaxed/simple; bh=JhSsoxg2OnXowswdGxhNRnAS5xMCOcv54bgZanDVXKg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hDpdxpaXFWDYzLZdIUdBuA6EDz7PkgJfngK3MgSOSSTBleko6jFvb5dPMadNVkxJrwal+GTH8z66yG18pwhhNR0Udv6+XCPWJ905kZcVohRatRqFJU2MpJ286ln1AhnCn5rGE22i2/46piz4i5nIgC03kUawM9wcrkexWg9rSYE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mfl0hj3R; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mfl0hj3R" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A91FC4AF08; Wed, 22 May 2024 11:48:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716378490; bh=JhSsoxg2OnXowswdGxhNRnAS5xMCOcv54bgZanDVXKg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mfl0hj3RfpjA19v73hu4iaH4EPTujvIlYiKndOFyuITde7PyQPwgKpf6zg8rW7OEN yQAUd3VKViNe+uJf6OeFbl3WmlTlHA20l6SRgJ31xBtlGTjxy6mAI11Wy/lvLzBv/w Jdx3AoudUEG/on82ClJ40FlncF2yrCJ5s4E4eruTJkZoWtWvQG66F8xoRwD0wO1xLe tTM5LVvaD/ED45o4El8HUVh7GTz4M1kdTJtAG6AP7FOrQHBYxln3ZkYRcYkdAj3b/h 17S/R0SwLZlv7rRFdwYOugmCafCHNzdY1eEyuCdQ8f8Luj5uOEKKknSvKMONhyOr6y sid1rZLz8oHTw== From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, Ard Biesheuvel , Masahiro Yamada , Nathan Chancellor , Nicolas Schier Subject: [PATCH 3/3] kbuild: merge temp vmlinux for CONFIG_DEBUG_INFO_BTF and CONFIG_KALLSYMS Date: Wed, 22 May 2024 20:47:55 +0900 Message-Id: <20240522114755.318238-4-masahiroy@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240522114755.318238-1-masahiroy@kernel.org> References: <20240522114755.318238-1-masahiroy@kernel.org> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 CONFIG_DEBUG_INFO_BTF=y requires one additional link step. (.tmp_vmlinux.btf) CONFIG_KALLSYMS=y requires two additional link steps. (.tmp_vmlinux.kallsyms1 and .tmp_vmlinux.kallsyms2) Enabling both requires three additional link steps. When CONFIG_DEBUG_INFO_BTF=y and CONFIG_KALLSYMS=y, the build step looks as follows: KSYMS .tmp_vmlinux.kallsyms0.S AS .tmp_vmlinux.kallsyms0.o LD .tmp_vmlinux.btf # temp vmlinux for BTF BTF .btf.vmlinux.bin.o LD .tmp_vmlinux.kallsyms1 # temp vmlinux for kallsyms step 1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.o LD .tmp_vmlinux.kallsyms2 # temp vmlinux for kallsyms step 2 NM .tmp_vmlinux.kallsyms2.syms KSYMS .tmp_vmlinux.kallsyms2.S AS .tmp_vmlinux.kallsyms2.o LD vmlinux # final vmlinux This is redundant because the BTF generation and the kallsyms step 1 can be performed against the same temporary vmlinux. When both CONFIG_DEBUG_INFO_BTF and CONFIG_KALLSYMS are enabled, we can reduce the number of link steps. The build step will look as follows: KSYMS .tmp_vmlinux0.kallsyms.S AS .tmp_vmlinux0.kallsyms.o LD .tmp_vmlinux1 # temp vmlinux for BTF and kallsyms step 1 BTF .tmp_vmlinux1.btf.o NM .tmp_vmlinux1.syms KSYMS .tmp_vmlinux1.kallsyms.S AS .tmp_vmlinux1.kallsyms.o LD .tmp_vmlinux2 # temp vmlinux for kallsyms step 2 NM .tmp_vmlinux2.syms KSYMS .tmp_vmlinux2.kallsyms.S AS .tmp_vmlinux2.kallsyms.o LD vmlinux # final link Signed-off-by: Masahiro Yamada Acked-by: Andrii Nakryiko --- scripts/link-vmlinux.sh | 45 +++++++++++++++++++++-------------------- 1 file changed, 23 insertions(+), 22 deletions(-) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index fe7db9a265ca..ea004aae6ce5 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -105,10 +105,10 @@ vmlinux_link() # generate .BTF typeinfo from DWARF debuginfo # ${1} - vmlinux image -# ${2} - file to dump raw BTF data into gen_btf() { local pahole_ver + local btf_data=${1}.btf.o if ! [ -x "$(command -v ${PAHOLE})" ]; then echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available" @@ -121,18 +121,16 @@ gen_btf() return 1 fi - vmlinux_link ${1} - - info "BTF" ${2} + info BTF "${btf_data}" LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1} - # Create ${2} which contains just .BTF section but no symbols. Add + # Create ${btf_data} which contains just .BTF section but no symbols. Add # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all # deletes all symbols including __start_BTF and __stop_BTF, which will # be redefined in the linker script. Add 2>/dev/null to suppress GNU # objcopy warnings: "empty loadable segment detected at ..." ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ - --strip-all ${1} ${2} 2>/dev/null + --strip-all ${1} "${btf_data}" 2>/dev/null # Change e_type to ET_REL so that it can be used to link final vmlinux. # GNU ld 2.35+ and lld do not allow an ET_EXEC input. if is_enabled CONFIG_CPU_BIG_ENDIAN; then @@ -140,9 +138,9 @@ gen_btf() else et_rel='\1\0' fi - printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none + printf "${et_rel}" | dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none - btf_vmlinux_bin_o=${2} + btf_vmlinux_bin_o=${btf_data} } # Create ${2}.o file with all symbols from the ${1} object file @@ -176,15 +174,13 @@ kallsyms() kallsymso=${2}.o } -# Perform one step in kallsyms generation, including temporary linking of -# vmlinux. -kallsyms_step() +# Perform kallsyms for the given temporary vmlinux. +sysmap_and_kallsyms() { - kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1} + mksysmap "${1}" "${1}.syms" + kallsyms "${1}.syms" "${1}.kallsyms" - vmlinux_link "${kallsyms_vmlinux}" - mksysmap "${kallsyms_vmlinux}" "${kallsyms_vmlinux}.syms" - kallsyms "${kallsyms_vmlinux}.syms" "${kallsyms_vmlinux}" + kallsyms_sysmap=${1}.syms } # Create map file with all symbols from ${1} @@ -226,12 +222,15 @@ kallsymso= btf_vmlinux_bin_o= if is_enabled CONFIG_KALLSYMS; then - # kallsyms step 0 - kallsyms /dev/null .tmp_vmlinux.kallsyms0 + kallsyms /dev/null .tmp_vmlinux0.kallsyms +fi + +if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then + vmlinux_link .tmp_vmlinux1 fi if is_enabled CONFIG_DEBUG_INFO_BTF; then - if ! gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then + if ! gen_btf .tmp_vmlinux1; then echo >&2 "Failed to generate BTF for vmlinux" echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF" exit 1 @@ -264,14 +263,16 @@ if is_enabled CONFIG_KALLSYMS; then # a) Verify that the System.map from vmlinux matches the map from # ${kallsymso}. - kallsyms_step 1 + sysmap_and_kallsyms .tmp_vmlinux1 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) - kallsyms_step 2 + vmlinux_link .tmp_vmlinux2 + sysmap_and_kallsyms .tmp_vmlinux2 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then - kallsyms_step 3 + vmlinux_link .tmp_vmlinux3 + sysmap_and_kallsyms .tmp_vmlinux3 fi fi @@ -295,7 +296,7 @@ fi # step a (see comment above) if is_enabled CONFIG_KALLSYMS; then - if ! cmp -s System.map ${kallsyms_vmlinux}.syms; then + if ! cmp -s System.map ${kallsyms_sysmap}; then echo >&2 Inconsistent kallsyms data echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround' exit 1