From patchwork Sat Feb 10 14:25:03 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 10210515 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B5B9660329 for ; Sat, 10 Feb 2018 14:25:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A5DEE29632 for ; Sat, 10 Feb 2018 14:25:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9AEB429641; Sat, 10 Feb 2018 14:25:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0CF4429632 for ; Sat, 10 Feb 2018 14:25:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751055AbeBJOZU (ORCPT ); Sat, 10 Feb 2018 09:25:20 -0500 Received: from mail-pg0-f67.google.com ([74.125.83.67]:44482 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751040AbeBJOZT (ORCPT ); Sat, 10 Feb 2018 09:25:19 -0500 Received: by mail-pg0-f67.google.com with SMTP id j9so4661514pgp.11 for ; Sat, 10 Feb 2018 06:25:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=WefGfAi0xUEJP4xf2yH6KWDSBNHp+aQAUEKXOcn3tMQ=; b=M06/ZgvcHX74Gxcf35gt3HbetSuzxgTAfVbqbR9U0iYGcRMUynAFxr0G5b6nI3+Q39 LYlppzyIMGwLw38xD9xA/dHHYubF8dOOTuHI9l/R0E0p1TnrvBuPWmWjSGYS5ck/7MWl AP4xbgPaMUNrZkkzenD1QRmkwB5pb/bDDTwhgT7AVFEYnY94jv3GFFmqAArktlpKK81p Au2fjzJydsT823QiPxnQQxmnX+sA6Nz/2qJV4ZgkAlqrOJ6DDoPwQj84tkIRSgbORx3j JuywrZS90ZOmLnTPkJLg3IZnBxUJebavuuYZdsGJmjwQIdqMQev/uxTkbukqcxk6CMiC lwwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=WefGfAi0xUEJP4xf2yH6KWDSBNHp+aQAUEKXOcn3tMQ=; b=r4WKUHZTCl8qxcC8J+T/wLT4Sc6RhlWy3IFF6pPHqFree4NEgAefMT9HZTXytwuIid jQ/gvpE504CKHat94pvqIMYce1GmH6rcQuVjiANBQ9CFH15nn2FqN0tdn1FCtUWUbeZR EKJINrkWogbJCWwbEVtfgsYAZhzsacvmFRZkh8v8QD5TTr8BEdqmRPBH1yaeI56Xf7b7 GlQ3jxMqYdDIL6y8I1f3aw5trP4Lw2GUjieFYP2PNEyeIpZtZxs0q0zPXmBqWc6jEP9G brXG4jF3nuIIF9BET7+xfS7sLgJoJirlVeqTLFdwB93CfVT7H83XZF3I2akFn+eqaLB9 UG4Q== X-Gm-Message-State: APf1xPAdZ7xF+aUSHgDWheSTjXq9aeipkznNpnD2Rr5hmB50ZOceayfb TA02fNOv17kyV+KwEIir5OSA1g== X-Google-Smtp-Source: AH8x227GOnp3z1/2S/LnVEqybWrFEA2ZqgaZvFSZp4KYnA+mQIlhhchBNuD7117X3pXjMoLa7mscCQ== X-Received: by 10.98.19.220 with SMTP id 89mr6215937pft.59.1518272719030; Sat, 10 Feb 2018 06:25:19 -0800 (PST) Received: from roar.au.ibm.com ([202.7.219.42]) by smtp.gmail.com with ESMTPSA id 16sm13703722pfq.181.2018.02.10.06.25.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 10 Feb 2018 06:25:18 -0800 (PST) From: Nicholas Piggin To: linux-kbuild@vger.kernel.org Cc: Nicholas Piggin , Masahiro Yamada , Michal Marek Subject: [PATCH 1/2] kbuild: remove incremental linking option Date: Sun, 11 Feb 2018 00:25:03 +1000 Message-Id: <20180210142504.29890-2-npiggin@gmail.com> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180210142504.29890-1-npiggin@gmail.com> References: <20180210142504.29890-1-npiggin@gmail.com> Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This removes the old `ld -r` incremental link option, which has not been selected by any architecture since June 2017. Signed-off-by: Nicholas Piggin --- Documentation/kbuild/makefiles.txt | 10 ++++- arch/Kconfig | 6 --- scripts/Makefile.build | 32 +++++--------- scripts/link-vmlinux.sh | 91 ++++++++++++++------------------------ 4 files changed, 51 insertions(+), 88 deletions(-) diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 71e9feefb63c..750aea9edd35 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -153,8 +153,14 @@ more details, with real examples. configuration. Kbuild compiles all the $(obj-y) files. It then calls - "$(LD) -r" to merge these files into one built-in.o file. - built-in.o is later linked into vmlinux by the parent Makefile. + "$(AR) rcSTP" to merge these files into one built-in.o file. + This is a thin archive without a symbol table, which makes it + unsuitable as a linker input. + + The scripts/link-vmlinux.sh script later makes an aggregate + built-in.o with "${AR} rcsTP", which creates the thin archive + with a symbol table and an index, making it a valid input for + the final vmlinux link passes. The order of files in $(obj-y) is significant. Duplicates in the lists are allowed: the first instance will be linked into diff --git a/arch/Kconfig b/arch/Kconfig index 76c0b54443b1..8e0d665c8d53 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -596,12 +596,6 @@ config CC_STACKPROTECTOR_AUTO endchoice -config THIN_ARCHIVES - def_bool y - help - Select this if the architecture wants to use thin archives - instead of ld -r to create the built-in.o files. - config LD_DEAD_CODE_DATA_ELIMINATION bool help diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 47cddf32aeba..c43df53c7cce 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -450,15 +450,13 @@ $(sort $(subdir-obj-y)): $(subdir-ym) ; # ifdef builtin-target -ifdef CONFIG_THIN_ARCHIVES - cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) - cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) - quiet_cmd_link_o_target = AR $@ -else - cmd_make_builtin = $(LD) $(ld_flags) -r -o - cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) - quiet_cmd_link_o_target = LD $@ -endif +# built-in.o archives are made with no symbol table or index which +# makes them small and fast, but unable to be used by the linker. +# scripts/link-vmlinux.sh builds an aggregate built-in.o with a symbol +# table and index. +cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) +cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) +quiet_cmd_link_o_target = AR $@ # If the list of objects to link is empty, just create an empty built-in.o cmd_link_o_target = $(if $(strip $(obj-y)),\ @@ -491,11 +489,8 @@ $(modorder-target): $(subdir-ym) FORCE ifdef lib-target quiet_cmd_link_l_target = AR $@ -ifdef CONFIG_THIN_ARCHIVES - cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y) -else - cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y) -endif +# lib target archives do get a symbol table and index +cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y) $(lib-target): $(lib-y) FORCE $(call if_changed,link_l_target) @@ -543,13 +538,8 @@ $($(subst $(obj)/,,$(@:.o=-m)))), $^) cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) -ifdef CONFIG_THIN_ARCHIVES - quiet_cmd_link_multi-y = AR $@ - cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps) -else - quiet_cmd_link_multi-y = LD $@ - cmd_link_multi-y = $(cmd_link_multi-link) -endif +quiet_cmd_link_multi-y = AR $@ +cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps) quiet_cmd_link_multi-m = LD [M] $@ cmd_link_multi-m = $(cmd_link_multi-link) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index c0d129d7f430..a55c24a86133 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -55,13 +55,11 @@ info() # archive_builtin() { - if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then - info AR built-in.o - rm -f built-in.o; - ${AR} rcsTP${KBUILD_ARFLAGS} built-in.o \ - ${KBUILD_VMLINUX_INIT} \ - ${KBUILD_VMLINUX_MAIN} - fi + info AR built-in.o + rm -f built-in.o; + ${AR} rcsTP${KBUILD_ARFLAGS} built-in.o \ + ${KBUILD_VMLINUX_INIT} \ + ${KBUILD_VMLINUX_MAIN} } # Link of vmlinux.o used for section mismatch analysis @@ -70,20 +68,13 @@ modpost_link() { local objects - if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then - objects="--whole-archive \ - built-in.o \ - --no-whole-archive \ - --start-group \ - ${KBUILD_VMLINUX_LIBS} \ - --end-group" - else - objects="${KBUILD_VMLINUX_INIT} \ - --start-group \ - ${KBUILD_VMLINUX_MAIN} \ - ${KBUILD_VMLINUX_LIBS} \ - --end-group" - fi + objects="--whole-archive \ + built-in.o \ + --no-whole-archive \ + --start-group \ + ${KBUILD_VMLINUX_LIBS} \ + --end-group" + ${LD} ${LDFLAGS} -r -o ${1} ${objects} } @@ -96,46 +87,28 @@ vmlinux_link() local objects if [ "${SRCARCH}" != "um" ]; then - if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then - objects="--whole-archive \ - built-in.o \ - --no-whole-archive \ - --start-group \ - ${KBUILD_VMLINUX_LIBS} \ - --end-group \ - ${1}" - else - objects="${KBUILD_VMLINUX_INIT} \ - --start-group \ - ${KBUILD_VMLINUX_MAIN} \ - ${KBUILD_VMLINUX_LIBS} \ - --end-group \ - ${1}" - fi - - ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \ + objects="--whole-archive \ + built-in.o \ + --no-whole-archive \ + --start-group \ + ${KBUILD_VMLINUX_LIBS} \ + --end-group \ + ${1}" + + ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \ -T ${lds} ${objects} else - if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then - objects="-Wl,--whole-archive \ - built-in.o \ - -Wl,--no-whole-archive \ - -Wl,--start-group \ - ${KBUILD_VMLINUX_LIBS} \ - -Wl,--end-group \ - ${1}" - else - objects="${KBUILD_VMLINUX_INIT} \ - -Wl,--start-group \ - ${KBUILD_VMLINUX_MAIN} \ - ${KBUILD_VMLINUX_LIBS} \ - -Wl,--end-group \ - ${1}" - fi - - ${CC} ${CFLAGS_vmlinux} -o ${2} \ - -Wl,-T,${lds} \ - ${objects} \ + objects="-Wl,--whole-archive \ + built-in.o \ + -Wl,--no-whole-archive \ + -Wl,--start-group \ + ${KBUILD_VMLINUX_LIBS} \ + -Wl,--end-group \ + ${1}" + + ${CC} ${CFLAGS_vmlinux} -o ${2} \ + -Wl,-T,${lds} \ + ${objects} \ -lutil -lrt -lpthread rm -f linux fi