From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 533973EB7FF; Tue, 2 Jun 2026 14:47:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780411649; cv=none; b=SAZOV/krCNYg/xynYd6A37lIl016x5x7zKdZbQsKEQk1nUFZO1s1T0EL2cEM5tSGWKmTrv4lkb8bpwXULfCmLLE6i+ECNRNgUYC+Qan8S9hYfSc62gLWxfisiI0ntRHvmDUIT2bBFcI+pOayUWmjhXMEFNP/GnTkSl2mi96sh/s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780411649; c=relaxed/simple; bh=+bPMqBjWhP4el8DDzLN3UmoeC6gA35HpOFjMwmSxEuo=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=JJJ/Ckv09/wzXTNmHIGSyFt3QYM8bQtrjnXpPMmKBI607yX8oqGBa370aqlfzTCvDWv4dWDLJ3neFfg7VXMHUkfwlCKxz6SBqgp7K7fbM9jzgopL/MyO2PTNNB5bzTsBGdXgclRCOz0qOGheEBTk3DFWC0KZc1ewSzGpWWDdRFI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=AKR3BxFk; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="AKR3BxFk" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E4B1C356D; Tue, 2 Jun 2026 07:47:21 -0700 (PDT) Received: from e132581.arm.com (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 706EF3F632; Tue, 2 Jun 2026 07:47:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1780411646; bh=+bPMqBjWhP4el8DDzLN3UmoeC6gA35HpOFjMwmSxEuo=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=AKR3BxFk7xb0YlmAfRzyNzx2sm6EcZVrNNd+zeQEImE7ip8DGl6VYQN+XVxORJ7X1 6yrkrxgQat9ymy1JMFLi2KauKj6Bq0MXtqr85RAva/mL62yNrIRUN7KXzQEu2JXob9 eISO8Nfmr2XK6Ge0BXTtMkxMXiFIYHzm5giFsBO4= From: Leo Yan Date: Tue, 02 Jun 2026 15:47:10 +0100 Subject: [PATCH bpf-next v2 1/8] bpftool: Pass host flags to bootstrap libbpf Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260602-tools_build_fix_zero_init_bpf_only-v2-1-c76e5250ea1c@arm.com> References: <20260602-tools_build_fix_zero_init_bpf_only-v2-0-c76e5250ea1c@arm.com> In-Reply-To: <20260602-tools_build_fix_zero_init_bpf_only-v2-0-c76e5250ea1c@arm.com> To: Quentin Monnet , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , Lorenz Bauer , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt Cc: Arnaldo Carvalho de Melo , Namhyung Kim , Ian Rogers , James Clark , Kees Cook , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, llvm@lists.linux.dev, Leo Yan X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1780411637; l=1945; i=leo.yan@arm.com; s=20250604; h=from:subject:message-id; bh=+bPMqBjWhP4el8DDzLN3UmoeC6gA35HpOFjMwmSxEuo=; b=PEHBmgSuakarM8vWBq6KZrpVfK7rlR0JRdLE08nDVmieBHCg2ve2luSMU7W7N0CObN7GkLSey KR+SGo+dTg5BjY3ifzGxSseD3C/yheTKKdiKxLyXqk/O3CXaR5lv4kq X-Developer-Key: i=leo.yan@arm.com; a=ed25519; pk=k4BaDbvkCXzBFA7Nw184KHGP5thju8lKqJYIrOWxDhI= bpftool builds a bootstrap libbpf with HOSTCC, but the libbpf submake can still inherit target build flags through CFLAGS. This can break cross builds when host objects are compiled with target-only options. Since HOST_CFLAGS contains warning options that are not suitable for building libbpf, use LIBBPF_BOOTSTRAP_CFLAGS with the warning options removed to build the bootstrap libbpf. Clear EXTRA_CFLAGS so target extra flags are not mixed into the host bootstrap libbpf build. Signed-off-by: Leo Yan --- tools/bpf/bpftool/Makefile | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index 0febf60e1b64656035dfe93cd15cba090015587a..1f033e578f90a2d6b93168ab41399de758bdf659 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -47,7 +47,8 @@ $(LIBBPF_INTERNAL_HDRS): $(LIBBPF_HDRS_DIR)/%.h: $(BPF_DIR)/%.h | $(LIBBPF_HDRS_ $(LIBBPF_BOOTSTRAP): $(wildcard $(BPF_DIR)/*.[ch] $(BPF_DIR)/Makefile) | $(LIBBPF_BOOTSTRAP_OUTPUT) $(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) \ DESTDIR=$(LIBBPF_BOOTSTRAP_DESTDIR:/=) prefix= \ - ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD="$(HOSTLD)" AR="$(HOSTAR)" $@ install_headers + ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD="$(HOSTLD)" AR="$(HOSTAR)" \ + CFLAGS="$(LIBBPF_BOOTSTRAP_CFLAGS)" EXTRA_CFLAGS= $@ install_headers $(LIBBPF_BOOTSTRAP_INTERNAL_HDRS): $(LIBBPF_BOOTSTRAP_HDRS_DIR)/%.h: $(BPF_DIR)/%.h | $(LIBBPF_BOOTSTRAP_HDRS_DIR) $(call QUIET_INSTALL, $@) @@ -92,6 +93,9 @@ HOST_CFLAGS := $(subst -I$(LIBBPF_INCLUDE),-I$(LIBBPF_BOOTSTRAP_INCLUDE),\ $(subst $(CLANG_CROSS_FLAGS),,$(CFLAGS))) HOST_LDFLAGS := $(LDFLAGS) +# Remove warnings for libbpf bootstrap build +LIBBPF_BOOTSTRAP_CFLAGS := $(filter-out -W -Wall -Wextra -Wformat -Wformat-signedness,$(HOST_CFLAGS)) + INSTALL ?= install RM ?= rm -f -- 2.34.1