From patchwork Sun Jun 9 17:04:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 13691305 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 2E932482EE; Sun, 9 Jun 2024 17:09:19 +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=1717952960; cv=none; b=LY6pMqYj/gqQ1M8PMfdwO+g/mm8+IHeLSiYveLj1OGrGvVnEJSpuyzqNXVHoaj9UR0t3GgjuH3R5RnprF2Ins5q1cyDGoKnqVFUtZHQy0iyhrE0BzuyY3mSlhvdSstRPagQvUkZaf9oPMdFXRScg7T94z4nRycHasg1U8/0Qrfo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717952960; c=relaxed/simple; bh=AYWEKiG2NcYekv5InaWsI2GNC5+7R4jU7/8muIQK4Y8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bEV2iuK8ISHgMGqY3r11G6GJwb0fa09yzNXdBENf5CQ0FYmYhRNY8yhDfYzlWf4RI7C8jAup2hzRweYOR2/jxizmymG2WWKrAWfRSmw/t4pczE1zZDhYj1GCRHUU2y+ucLYvG7FWTEAhNedYGtpx+dtOSFPKow09sEJhPcnI9Rk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dh3bS5uE; 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="dh3bS5uE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E414C2BD10; Sun, 9 Jun 2024 17:09:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717952959; bh=AYWEKiG2NcYekv5InaWsI2GNC5+7R4jU7/8muIQK4Y8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dh3bS5uEQyZg+2XNXNyIpk/jMqeRiGG8tHYSp4oJ9SOf1bBfUQvR7YlLAgvjgvYUN 7YRWP8l2CKd+QM0+2gM9NBOYGQyj/RUz4W4qdPeZUu5WxIJ/Uo9/WKQWUgL5F000zs 2X1zuYmc0YRsdchBSLWY5bWeQSsYBG+cEpv46j+xmaWn3ectdBAL3fW4mynt2I8rvw iio0HFnhDSGNgXASCuxlvsJGaHku6GjJmQ4gasJFRujhT+iPy2f7Z8KOJhhqimioAY YWqMS0FYquMCLsBJ7bRcVD+gS08I5UiS5LNEhnuClJtJ1ZnZ8L4ZBEOYX5h7mKpiuX H2/ErZek/J+hA== From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Masahiro Yamada , Nathan Chancellor , Nicolas Schier Subject: [PATCH v2 1/3] kbuild: refactor variables in scripts/link-vmlinux.sh Date: Mon, 10 Jun 2024 02:04:18 +0900 Message-ID: <20240609170855.1708665-2-masahiroy@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240609170855.1708665-1-masahiroy@kernel.org> References: <20240609170855.1708665-1-masahiroy@kernel.org> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Clean up the variables in scripts/link-vmlinux.sh - Specify the extra objects directly in vmlinux_link() - Move the AS rule to kallsyms() - Set kallsymso and btf_vmlinux_bin_o where they are generated - Remove unneeded variable, kallsymso_prev - Introduce btf_data variable No functional change intended. Signed-off-by: Masahiro Yamada --- (no changes since v1) scripts/link-vmlinux.sh | 57 +++++++++++++++++++---------------------- 1 file changed, 27 insertions(+), 30 deletions(-) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 518c70b8db50..da3879469e53 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -45,7 +45,6 @@ info() # Link of vmlinux # ${1} - output file -# ${2}, ${3}, ... - optional extra .o files vmlinux_link() { local output=${1} @@ -101,7 +100,7 @@ vmlinux_link() ${ld} ${ldflags} -o ${output} \ ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \ ${wl}--start-group ${libs} ${wl}--end-group \ - $@ ${ldlibs} + ${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs} } # generate .BTF typeinfo from DWARF debuginfo @@ -110,6 +109,7 @@ vmlinux_link() gen_btf() { local pahole_ver + local btf_data=${2} if ! [ -x "$(command -v ${PAHOLE})" ]; then echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available" @@ -124,16 +124,16 @@ gen_btf() 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 @@ -141,10 +141,12 @@ 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=${btf_data} } -# Create ${2} .S file with all symbols from the ${1} object file +# Create ${2}.o file with all symbols from the ${1} object file kallsyms() { local kallsymopt; @@ -165,27 +167,25 @@ kallsyms() kallsymopt="${kallsymopt} --lto-clang" fi - info KSYMS ${2} - scripts/kallsyms ${kallsymopt} ${1} > ${2} + info KSYMS "${2}.S" + scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S" + + info AS "${2}.o" + ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \ + ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S" + + kallsymso=${2}.o } # Perform one step in kallsyms generation, including temporary linking of # vmlinux. kallsyms_step() { - kallsymso_prev=${kallsymso} kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1} - kallsymso=${kallsyms_vmlinux}.o - kallsyms_S=${kallsyms_vmlinux}.S - vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o} - mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms - kallsyms ${kallsyms_vmlinux}.syms ${kallsyms_S} - - info AS ${kallsymso} - ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \ - ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ - -c -o ${kallsymso} ${kallsyms_S} + vmlinux_link "${kallsyms_vmlinux}" + mksysmap "${kallsyms_vmlinux}" "${kallsyms_vmlinux}.syms" + kallsyms "${kallsyms_vmlinux}.syms" "${kallsyms_vmlinux}" } # Create map file with all symbols from ${1} @@ -223,19 +223,17 @@ fi ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o -btf_vmlinux_bin_o="" +kallsymso= +btf_vmlinux_bin_o= + if is_enabled CONFIG_DEBUG_INFO_BTF; then - btf_vmlinux_bin_o=.btf.vmlinux.bin.o - if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then + if ! gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then echo >&2 "Failed to generate BTF for vmlinux" echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF" exit 1 fi fi -kallsymso="" -kallsymso_prev="" -kallsyms_vmlinux="" if is_enabled CONFIG_KALLSYMS; then # kallsyms support @@ -262,10 +260,9 @@ if is_enabled CONFIG_KALLSYMS; then # ${kallsymso}. kallsyms_step 1 - kallsyms_step 2 + size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) - # step 3 - size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev}) + kallsyms_step 2 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then @@ -273,7 +270,7 @@ if is_enabled CONFIG_KALLSYMS; then fi fi -vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} +vmlinux_link vmlinux # fill in BTF IDs if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then From patchwork Sun Jun 9 17:04:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 13691306 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 AB4914CE05; Sun, 9 Jun 2024 17:09:22 +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=1717952962; cv=none; b=t4anoQ+NS7jF/IjXEf015ZQsRYf5DFf4334acngiYELxwlD2JzHy9sAdqM5qx7rX1VQkF4d8nZAtYUbULB0L6gfHSI8JvNy6+zMoRIBR7dGrmwOSoFE3ZVQw3h07ywYXrQUuiOsKFENVpsSvtYgyy5vOcA1pi+1d05a4Fl3sG+k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717952962; c=relaxed/simple; bh=CN5mfKSIOsNFwgS0HImQpDJa66QgoGbxMOB/gULNMSY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qvb9ezu4mYCp+vf4Tezw2sNtOEGvgM7oZKqpTv0SRYniBBDb9zOtH39ZH+UWna86D9ux+/fksADpJv9sqJGZFvEmr5VgTVr9+JB07/wXblZJONjdiDp0HwnayGpn3G3QFM3V6yF1pEQUSP6K/EQj2yFzmNB/iTZGtKeY8+e9R6g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Q0ZmNO2J; 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="Q0ZmNO2J" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 699B8C4AF1D; Sun, 9 Jun 2024 17:09:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717952962; bh=CN5mfKSIOsNFwgS0HImQpDJa66QgoGbxMOB/gULNMSY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q0ZmNO2Jo4JMy8hSeh2U5e5bXJqUYqCe8o+iKDCBJI7oO14oGW/EFjaQ6VOgDjP2K TBAp+URnKfDoyKHwCAtpQObX5u+r/dxFfbmw/crekq+UpzL0Zg7lU7/awHSRij/MGw wNBdjQhP4yI0WO35WxQrzA5SgIKKSzSgr+2X30rRP3GM4Vofs4fVEGPiDgwG2ERC/Z HSlqUQXuWE2HyirgbvlvibVD0dSEM3lqrzpiktHizfF6MheC+fviKvqw6Kpqm7MAyr 4VszE8xYUo8YtxuOI4PPBI6CTl9hyOAC0XrrRDMfjx5E9MRf3DfGhq+vsksgsLr1Nt BJCSU3v9VCYFw== From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Masahiro Yamada , Ard Biesheuvel , Arnd Bergmann , Nathan Chancellor , Nicolas Schier , linux-arch@vger.kernel.org Subject: [PATCH v2 2/3] kbuild: remove PROVIDE() for kallsyms symbols Date: Mon, 10 Jun 2024 02:04:19 +0900 Message-ID: <20240609170855.1708665-3-masahiroy@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240609170855.1708665-1-masahiroy@kernel.org> References: <20240609170855.1708665-1-masahiroy@kernel.org> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This reimplements commit 951bcae6c5a0 ("kallsyms: Avoid weak references for kallsyms symbols"). I am not a big fan of PROVIDE(). As an alternative solution, this commit prepends one more kallsyms step. KSYMS .tmp_vmlinux.kallsyms0.S # added AS .tmp_vmlinux.kallsyms0.o # added LD .tmp_vmlinux.btf BTF .btf.vmlinux.bin.o LD .tmp_vmlinux.kallsyms1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.o LD .tmp_vmlinux.kallsyms2 NM .tmp_vmlinux.kallsyms2.syms KSYMS .tmp_vmlinux.kallsyms2.S AS .tmp_vmlinux.kallsyms2.o LD vmlinux Step 0 takes /dev/null as input, and generates .tmp_vmlinux.kallsyms0.o, which has a valid kallsyms format with the empty symbol list, and can be linked to vmlinux. Since it is really small, the added compile-time cost is negligible. Signed-off-by: Masahiro Yamada Acked-by: Ard Biesheuvel --- (no changes since v1) include/asm-generic/vmlinux.lds.h | 19 ------------------- kernel/kallsyms_internal.h | 5 ----- scripts/kallsyms.c | 6 ------ scripts/link-vmlinux.sh | 9 +++++++-- 4 files changed, 7 insertions(+), 32 deletions(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 5703526d6ebf..62b4cb0462e6 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -451,30 +451,11 @@ #endif #endif -/* - * Some symbol definitions will not exist yet during the first pass of the - * link, but are guaranteed to exist in the final link. Provide preliminary - * definitions that will be superseded in the final link to avoid having to - * rely on weak external linkage, which requires a GOT when used in position - * independent code. - */ -#define PRELIMINARY_SYMBOL_DEFINITIONS \ - PROVIDE(kallsyms_addresses = .); \ - PROVIDE(kallsyms_offsets = .); \ - PROVIDE(kallsyms_names = .); \ - PROVIDE(kallsyms_num_syms = .); \ - PROVIDE(kallsyms_relative_base = .); \ - PROVIDE(kallsyms_token_table = .); \ - PROVIDE(kallsyms_token_index = .); \ - PROVIDE(kallsyms_markers = .); \ - PROVIDE(kallsyms_seqs_of_names = .); - /* * Read only Data */ #define RO_DATA(align) \ . = ALIGN((align)); \ - PRELIMINARY_SYMBOL_DEFINITIONS \ .rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \ __start_rodata = .; \ *(.rodata) *(.rodata.*) \ diff --git a/kernel/kallsyms_internal.h b/kernel/kallsyms_internal.h index 85480274fc8f..925f2ab22639 100644 --- a/kernel/kallsyms_internal.h +++ b/kernel/kallsyms_internal.h @@ -4,11 +4,6 @@ #include -/* - * These will be re-linked against their real values during the second link - * stage. Preliminary values must be provided in the linker script using the - * PROVIDE() directive so that the first link stage can complete successfully. - */ extern const unsigned long kallsyms_addresses[]; extern const int kallsyms_offsets[]; extern const u8 kallsyms_names[]; diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 47978efe4797..fa53b5eef553 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -259,12 +259,6 @@ static void shrink_table(void) } } table_cnt = pos; - - /* When valid symbol is not registered, exit to error */ - if (!table_cnt) { - fprintf(stderr, "No valid symbol.\n"); - exit(1); - } } static void read_map(const char *in) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index da3879469e53..6f2fdc9e4fbf 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -226,6 +226,10 @@ ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o kallsymso= btf_vmlinux_bin_o= +if is_enabled CONFIG_KALLSYMS; then + kallsyms /dev/null .tmp_vmlinux.kallsyms0 +fi + if is_enabled CONFIG_DEBUG_INFO_BTF; then if ! gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then echo >&2 "Failed to generate BTF for vmlinux" @@ -238,9 +242,10 @@ if is_enabled CONFIG_KALLSYMS; then # kallsyms support # Generate section listing all symbols and add it into vmlinux - # It's a three step process: + # It's a four step process: + # 0) Generate a dummy __kallsyms with empty symbol list. # 1) Link .tmp_vmlinux.kallsyms1 so it has all symbols and sections, - # but __kallsyms is empty. + # with a dummy __kallsyms. # Running kallsyms on that gives us .tmp_kallsyms1.o with # the right size # 2) Link .tmp_vmlinux.kallsyms2 so it now has a __kallsyms section of From patchwork Sun Jun 9 17:04:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 13691307 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 515A14D8B3; Sun, 9 Jun 2024 17:09:24 +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=1717952964; cv=none; b=BbQNZAXfahGqN6w4mExU8elUT/euXGG/PAHsjjgxtthFN5kZ8CGhRTUmtAGIuV3l1V40V1LHaqGycfGjP1mHreuP5dlad/KWpDR0eWrV/PTJnm8b29hv96MiJXasgz3syopWEPl//pGKz/f9iX8672td41+PsOi6viDrif73hX8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717952964; c=relaxed/simple; bh=fwdRwtkshBcqDeuP1FhFGHJWYOHNN1ovkmYO50ggPa8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tciUApK1vErtyKTEgzSgLgkDoKq2XiVFwNzXWia+HHz0ZAoivBaPtHpR/4sMLIFZyVBCqlCTyAnhvy/6kjpLDLje9dW+0x/rpDdWx1oq1omSJ/hy0WBKyxg8BKYa4mTW7HEEREm0LLWaYGQ5sT09GgZMhZmkmAjz+mw/hJZORs0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Akv8SX1l; 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="Akv8SX1l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C241CC4AF49; Sun, 9 Jun 2024 17:09:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717952964; bh=fwdRwtkshBcqDeuP1FhFGHJWYOHNN1ovkmYO50ggPa8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Akv8SX1lOsEdLATsb8JeKHFMqjeN+sI2Jpup/gjUNgCP0LzzbKNzHQUH+FRhfJGas wthh8HT/yUT7SX6MQLPQ6Dgw1zbx2iaOwYg6TCR47un8uBdtiMreRlZhxX7mSYYnP8 Qq/reQ5Q0jBWRIy0+ph/wX8vhJIj8E4wZGjX1bH/+R++uWy12st28jRtk7wGsQpxfg jtene7C6bLl2iz2tFua68D0c/CIB2+PuS25iawYDmkydrtLEV+JCUCoRpzUQYuKay4 W9JF+uHjcTCOHmuC64fGlqJCv4UJXLnX1CfFqD/mV9pShAW6BkvHC7dI77QL2wW86I EBA7EU9Dw5G8g== From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Masahiro Yamada , Andrii Nakryiko , Nathan Chancellor , Nicolas Schier Subject: [PATCH v2 3/3] kbuild: merge temporary vmlinux for BTF and kallsyms Date: Mon, 10 Jun 2024 02:04:20 +0900 Message-ID: <20240609170855.1708665-4-masahiroy@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240609170855.1708665-1-masahiroy@kernel.org> References: <20240609170855.1708665-1-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 steps are as follows: KSYMS .tmp_vmlinux.kallsyms0.S AS .tmp_vmlinux.kallsyms0.o LD .tmp_vmlinux.btf # temporary vmlinux for BTF BTF .btf.vmlinux.bin.o LD .tmp_vmlinux.kallsyms1 # temporary vmlinux for kallsyms step 1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.o LD .tmp_vmlinux.kallsyms2 # temporary 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 steps will be changed as follows: KSYMS .tmp_vmlinux0.kallsyms.S AS .tmp_vmlinux0.kallsyms.o LD .tmp_vmlinux1 # temporary 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 # temporary vmlinux for kallsyms step 2 NM .tmp_vmlinux2.syms KSYMS .tmp_vmlinux2.kallsyms.S AS .tmp_vmlinux2.kallsyms.o LD vmlinux # final vmlinux Signed-off-by: Masahiro Yamada Acked-by: Andrii Nakryiko --- Changes in v2: - Fix the handling --strip-debug flag scripts/link-vmlinux.sh | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 6f2fdc9e4fbf..14aedec224af 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -89,7 +89,8 @@ vmlinux_link() ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}" # The kallsyms linking does not need debug symbols included. - if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then + if [ "$output" != vmlinux ] && + (! is_enabled CONFIG_DEBUG_INFO_BTF || [ "$output" != .tmp_vmlinux1 ]) then ldflags="${ldflags} ${wl}--strip-debug" fi @@ -105,11 +106,10 @@ vmlinux_link() # generate .BTF typeinfo from DWARF debuginfo # ${1} - vmlinux image -# ${2} - file to dump raw BTF data into gen_btf() { local pahole_ver - local btf_data=${2} + local btf_data=${1}.btf.o if ! [ -x "$(command -v ${PAHOLE})" ]; then echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available" @@ -122,8 +122,6 @@ gen_btf() return 1 fi - vmlinux_link ${1} - info BTF "${btf_data}" LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1} @@ -177,15 +175,13 @@ kallsyms() kallsymso=${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} @@ -227,11 +223,15 @@ kallsymso= btf_vmlinux_bin_o= if is_enabled CONFIG_KALLSYMS; then - 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 +264,16 @@ 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 +297,7 @@ 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