From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D00E4C54FD0 for ; Thu, 23 Apr 2020 07:52:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B082321569 for ; Thu, 23 Apr 2020 07:52:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587628365; bh=OAEdO+IFLZ8N189wG3BknW5AiXVpPlZ0lS2ZfVkhu6c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=cwstanncrnZkOKweOIPiWkZ09Kb6FUO1KnSaZF0irXqjRy2uubsjffikMoFiUUbe1 4Uodk1qcnhBPae00A5l8/T4x1w/22Wr31AyoweqwqDafdGi9zMScmnad0aWCcR4Dlm QNeFZUFESvFZRHy0ZBWcUbSl0v3P9cyUWUmQ5S8Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726101AbgDWHwp (ORCPT ); Thu, 23 Apr 2020 03:52:45 -0400 Received: from condef-09.nifty.com ([202.248.20.74]:22122 "EHLO condef-09.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725562AbgDWHwp (ORCPT ); Thu, 23 Apr 2020 03:52:45 -0400 Received: from conuserg-10.nifty.com ([10.126.8.73])by condef-09.nifty.com with ESMTP id 03N7ea4Y022226 for ; Thu, 23 Apr 2020 16:41:18 +0900 Received: from oscar.flets-west.jp (softbank126090202047.bbtec.net [126.90.202.47]) (authenticated) by conuserg-10.nifty.com with ESMTP id 03N7dV9O000368; Thu, 23 Apr 2020 16:39:35 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-10.nifty.com 03N7dV9O000368 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1587627575; bh=myxup6EGe0ikE/kZA9HlfZByZy7k5g2S+MsusXB8OsE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M/y7bmq/WkMKS6RcGf2/hrRssIL6AXYXpdNHOKWMGCdSpE5CMgVCPq1OXEyGDX2gT llvMT+gX75+2USBLL4CYyGOybViCEMRMeSzCqRaUsAaSEsufU/EyFq7nAqDZH3CJwP DcM+sm3rPamr4Dd7wtGNnSddS9HHn8Ac8vn1tRkKoAmJJEU3G4eQyHBMoH3n3KbDQX Ocks0hz9NsMxqFma+ckEcyq3gBwetKwYEhReaLqoErMxgVd9hSrTTFRW1pCImWEqhc rhUBzio3Y/ky/tz0OhLN2ngoMREOIlnDDUaAg/tMtx0mz/zQMZBM+g6jetzyAizSVx UUkmR/KHtSPQg== X-Nifty-SrcIP: [126.90.202.47] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: bpf@vger.kernel.org, Sam Ravnborg , Masahiro Yamada , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , John Fastabend , KP Singh , Martin KaFai Lau , Michal Marek , Song Liu , Yonghong Song , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 03/16] kbuild: add infrastructure to build userspace programs Date: Thu, 23 Apr 2020 16:39:16 +0900 Message-Id: <20200423073929.127521-4-masahiroy@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200423073929.127521-1-masahiroy@kernel.org> References: <20200423073929.127521-1-masahiroy@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Kbuild supports the infrastructure to build host programs, but there was no support to build userspace programs for the target architecture (i.e. the same architecture as the kernel). Sam Ravnborg worked on this a long time ago. https://lkml.org/lkml/2014/7/13/154 But, it was not merged. One problem at that time was, there was no good way to know whether $(CC) can link standalone programs. In fact, pre-built kernel.org toolchains [1] do not provide libc. Now, we can handle this cleanly because the compiler capability is evaluated at the Kconfig time. If $(CC) cannot link standalone programs, the relevant options are hidden by 'depends on CC_CAN_LINK'. The implementation just mimics scripts/Makefile.host The userspace programs are compiled with the same flags as the host programs. In addition, it uses -m32 or -m64 if it is found in $(KBUILD_CFLAGS). This new syntax has at least two usecases. - Sample programs Several userspace programs under samples/ include UAPI headers installed in usr/include. Most of them were previously built for the host architecture just to use 'hostprogs' syntax. However, 'make headers' always works for the target architecture. This caused the arch mismatch in cross-compiling. To fix this distortion, sample code should be built for the target architecture. - Bpfilter net/bpfilter/Makefile compiles bpfilter_umh as the user mode helper, and embeds it into the kernel code. Currently, it overrides HOSTCC with CC to use the 'hostprogs' syntax. This hack should go away. [1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/ Signed-off-by: Masahiro Yamada --- Makefile | 11 +++++++--- scripts/Makefile.build | 5 +++++ scripts/Makefile.clean | 2 +- scripts/Makefile.userprogs | 44 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 58 insertions(+), 4 deletions(-) create mode 100644 scripts/Makefile.userprogs diff --git a/Makefile b/Makefile index 49b2709ff44e..f20597820131 100644 --- a/Makefile +++ b/Makefile @@ -406,9 +406,11 @@ else HOSTCC = gcc HOSTCXX = g++ endif -KBUILD_HOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 \ - -fomit-frame-pointer -std=gnu89 $(HOST_LFS_CFLAGS) \ - $(HOSTCFLAGS) + +export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ + -O2 -fomit-frame-pointer -std=gnu89 + +KBUILD_HOSTCFLAGS := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS) KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS) KBUILD_HOSTLDFLAGS := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS) KBUILD_HOSTLDLIBS := $(HOST_LFS_LIBS) $(HOSTLDLIBS) @@ -937,6 +939,9 @@ ifeq ($(CONFIG_RELR),y) LDFLAGS_vmlinux += --pack-dyn-relocs=relr endif +# Align the bit size of userspace programs with the kernel +KBUILD_USERCFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS)) + # make the checker run with the right architecture CHECKFLAGS += --arch=$(ARCH) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 9fcbfac15d1d..94f2f7016172 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -50,6 +50,11 @@ ifneq ($(hostprogs)$(hostcxxlibs-y)$(hostcxxlibs-m),) include scripts/Makefile.host endif +# Do not include userprogs rules unless needed +ifneq ($(userprogs),) +include scripts/Makefile.userprogs +endif + ifndef obj $(warning kbuild: Makefile.build is included improperly) endif diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean index 075f0cc2d8d7..e2c76122319d 100644 --- a/scripts/Makefile.clean +++ b/scripts/Makefile.clean @@ -29,7 +29,7 @@ subdir-ymn := $(addprefix $(obj)/,$(subdir-ymn)) __clean-files := $(extra-y) $(extra-m) $(extra-) \ $(always) $(always-y) $(always-m) $(always-) $(targets) $(clean-files) \ - $(hostprogs) $(hostprogs-y) $(hostprogs-m) $(hostprogs-) \ + $(hostprogs) $(hostprogs-y) $(hostprogs-m) $(hostprogs-) $(userprogs) \ $(hostcxxlibs-y) $(hostcxxlibs-m) __clean-files := $(filter-out $(no-clean-files), $(__clean-files)) diff --git a/scripts/Makefile.userprogs b/scripts/Makefile.userprogs new file mode 100644 index 000000000000..0d987085819b --- /dev/null +++ b/scripts/Makefile.userprogs @@ -0,0 +1,44 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Build userspace programs for the target system +# + +userprogs := $(sort $(userprogs)) + +# Executables compiled from a single .c file +user-csingle := $(foreach m, $(userprogs), $(if $($(m)-objs),,$(m))) + +# C executables linked based on several .o files +user-cmulti := $(foreach m, $(userprogs), $(if $($(m)-objs),$(m))) + +# Object (.o) files compiled from .c files +user-cobjs := $(foreach m, $(userprogs), $($(m)-objs)) + +user-csingle := $(addprefix $(obj)/, $(user-csingle)) +user-cmulti := $(addprefix $(obj)/, $(user-cmulti)) +user-cobjs := $(addprefix $(obj)/, $(user-cobjs)) + +user_c_flags = -Wp,-MMD,$(depfile) $(KBUILD_USERCFLAGS) $(user-ccflags) \ + $($(target-stem)-ccflags) + +# Create an executable from a single .c file +quiet_cmd_user_cc_c = CC [U] $@ + cmd_user_cc_c = $(CC) $(user_c_flags) -o $@ $< +$(user-csingle): $(obj)/%: $(src)/%.c FORCE + $(call if_changed_dep,user_cc_c) + +# Link an executable based on list of .o files +quiet_cmd_user_ld = LD [U] $@ + cmd_user_ld = $(CC) -o $@ $(addprefix $(obj)/, $($(target-stem)-objs)) \ + $($(target-stem)-ldlibs) +$(user-cmulti): FORCE + $(call if_changed,user_ld) +$(call multi_depend, $(user-cmulti), , -objs) + +# Create .o file from a .c file +quiet_cmd_user_cc_o_c = CC [U] $@ + cmd_user_cc_o_c = $(CC) $(user_c_flags) -c -o $@ $< +$(user-cobjs): $(obj)/%.o: $(src)/%.c FORCE + $(call if_changed_dep,user_cc_o_c) + +targets += $(user-csingle) $(user-cmulti) $(user-cobjs) -- 2.25.1