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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 2294BECE588 for ; Tue, 15 Oct 2019 18:29:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F23CA2086A for ; Tue, 15 Oct 2019 18:29:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="AfSw9euA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389023AbfJOS3F (ORCPT ); Tue, 15 Oct 2019 14:29:05 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:27882 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729732AbfJOS3F (ORCPT ); Tue, 15 Oct 2019 14:29:05 -0400 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id x9FIPisC001845 for ; Tue, 15 Oct 2019 11:29:04 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=Bnf40a2WeQgCDhgDUAmQhlGdfdB7lGzwRCntGITwz4E=; b=AfSw9euATMkc7Sf+Vz9mkGJLJgG+8hqHJ/jl6OcrkLpgkMLVxy6xAviiTjlYJFPLanmd aEt9FgiV/fJ82Uvn3NKOwNYZN2nbs+ffiwC7XZMY0h4q9x+s3ahCbyM/uznnet+Mt9ft 7rI8xbR8dbMD5uTeos7lucQgqrLZwlaZ40c= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2vkxgeu9hc-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 15 Oct 2019 11:29:04 -0700 Received: from 2401:db00:30:6007:face:0:1:0 (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 15 Oct 2019 11:29:00 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id 81729861983; Tue, 15 Oct 2019 11:28:58 -0700 (PDT) Smtp-Origin-Hostprefix: dev From: Andrii Nakryiko Smtp-Origin-Hostname: dev101.prn2.facebook.com To: , , , CC: , , Andrii Nakryiko Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v2 bpf-next 4/5] libbpf: add BPF-side definitions of supported field relocation kinds Date: Tue, 15 Oct 2019 11:28:48 -0700 Message-ID: <20191015182849.3922287-5-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191015182849.3922287-1-andriin@fb.com> References: <20191015182849.3922287-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,1.0.8 definitions=2019-10-15_06:2019-10-15,2019-10-15 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 suspectscore=0 lowpriorityscore=0 spamscore=0 malwarescore=0 bulkscore=0 mlxscore=0 priorityscore=1501 clxscore=1015 phishscore=0 adultscore=0 impostorscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1908290000 definitions=main-1910150156 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add enum definition for Clang's __builtin_preserve_field_info() second argument (info_kind). Currently only byte offset and existence are supported. Corresponding Clang changes introducing this built-in can be found at [0] [0] https://reviews.llvm.org/D67980 Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/bpf_core_read.h | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index 4daf04c25493..a273df3784f4 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -2,6 +2,28 @@ #ifndef __BPF_CORE_READ_H__ #define __BPF_CORE_READ_H__ +/* + * enum bpf_field_info_kind is passed as a second argument into + * __builtin_preserve_field_info() built-in to get a specific aspect of + * a field, captured as a first argument. __builtin_preserve_field_info(field, + * info_kind) returns __u32 integer and produces BTF field relocation, which + * is understood and processed by libbpf during BPF object loading. See + * selftests/bpf for examples. + */ +enum bpf_field_info_kind { + BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ + BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ +}; + +/* + * Convenience macro to check that field actually exists in target kernel's. + * Returns: + * 1, if matching field is present in target kernel; + * 0, if no matching field found. + */ +#define bpf_core_field_exists(field) \ + __builtin_preserve_field_info(field, BPF_FIELD_EXISTS) + /* * bpf_core_read() abstracts away bpf_probe_read() call and captures offset * relocation for source address using __builtin_preserve_access_index() @@ -12,7 +34,7 @@ * a relocation, which records BTF type ID describing root struct/union and an * accessor string which describes exact embedded field that was used to take * an address. See detailed description of this relocation format and - * semantics in comments to struct bpf_offset_reloc in libbpf_internal.h. + * semantics in comments to struct bpf_field_reloc in libbpf_internal.h. * * This relocation allows libbpf to adjust BPF instruction to use correct * actual field offset, based on target kernel BTF type that matches original -- 2.17.1