From patchwork Wed May 29 17:36:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1107279 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="DsStfEIa"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45DdDW3xCFz9s7h for ; Thu, 30 May 2019 03:36:27 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726024AbfE2Rg0 (ORCPT ); Wed, 29 May 2019 13:36:26 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:48492 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725917AbfE2RgZ (ORCPT ); Wed, 29 May 2019 13:36:25 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4THTiC4027606 for ; Wed, 29 May 2019 10:36:24 -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=FsE3XkK2qJftt1Bm/IoQNMcfHr4cEYQguMH0RpXO/QQ=; b=DsStfEIaIJd5sMZM4ZqXmBosrc9kBo7Fzvcj2yizhBZx0vi52cpanfPtsKPS0O92Jwsx S1bokTs9FHyAgSPuT4IOqlrbKMMqe77l6j8baasaIvCJZxgbCjYgZ6OIXK4EJP4D1tjL f3ytBHdmCXP56rvzzcLka+9Ol/ike/GIzQw= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2sswbt0adg-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Wed, 29 May 2019 10:36:24 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::126) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Wed, 29 May 2019 10:36:23 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id A39AF8617AE; Wed, 29 May 2019 10:36:21 -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 3/9] libbpf: simplify endianness check Date: Wed, 29 May 2019 10:36:05 -0700 Message-ID: <20190529173611.4012579-4-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190529173611.4012579-1-andriin@fb.com> References: <20190529173611.4012579-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-05-29_09:, , signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905290114 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Rewrite endianness check to use "more canonical" way, using compiler-defined macros, similar to few other places in libbpf. It also is more obvious and shorter. Acked-by: Song Liu Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 37 ++++++++++++------------------------- 1 file changed, 12 insertions(+), 25 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 5af331cb8e4f..fe700ef1135d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -607,31 +607,18 @@ static int bpf_object__elf_init(struct bpf_object *obj) return err; } -static int -bpf_object__check_endianness(struct bpf_object *obj) -{ - static unsigned int const endian = 1; - - switch (obj->efile.ehdr.e_ident[EI_DATA]) { - case ELFDATA2LSB: - /* We are big endian, BPF obj is little endian. */ - if (*(unsigned char const *)&endian != 1) - goto mismatch; - break; - - case ELFDATA2MSB: - /* We are little endian, BPF obj is big endian. */ - if (*(unsigned char const *)&endian != 0) - goto mismatch; - break; - default: - return -LIBBPF_ERRNO__ENDIAN; - } - - return 0; - -mismatch: - pr_warning("Error: endianness mismatch.\n"); +static int bpf_object__check_endianness(struct bpf_object *obj) +{ +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB) + return 0; +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB) + return 0; +#else +# error "Unrecognized __BYTE_ORDER__" +#endif + pr_warning("endianness mismatch.\n"); return -LIBBPF_ERRNO__ENDIAN; }