From patchwork Fri Dec 18 23:56:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 345883 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 12634C3526C for ; Fri, 18 Dec 2020 23:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D40E723BCD for ; Fri, 18 Dec 2020 23:57:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725945AbgLRX5D convert rfc822-to-8bit (ORCPT ); Fri, 18 Dec 2020 18:57:03 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:31026 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725885AbgLRX5D (ORCPT ); Fri, 18 Dec 2020 18:57:03 -0500 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 0BINuMhb015378 for ; Fri, 18 Dec 2020 15:56:22 -0800 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 35gwa8b1ad-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 18 Dec 2020 15:56:22 -0800 Received: from intmgw001.03.ash8.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 18 Dec 2020 15:56:21 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id A6EB52ECB8FE; Fri, 18 Dec 2020 15:56:18 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , , Gilad Reti Subject: [PATCH bpf-next 1/3] libbpf: add user-space variants of BPF_CORE_READ() family of macros Date: Fri, 18 Dec 2020 15:56:12 -0800 Message-ID: <20201218235614.2284956-2-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201218235614.2284956-1-andrii@kernel.org> References: <20201218235614.2284956-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343, 18.0.737 definitions=2020-12-18_14:2020-12-18,2020-12-18 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 bulkscore=0 mlxlogscore=999 priorityscore=1501 phishscore=0 spamscore=0 lowpriorityscore=0 malwarescore=0 suspectscore=0 mlxscore=0 impostorscore=0 clxscore=1034 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012180163 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Add BPF_CORE_READ_USER(), BPF_CORE_READ_USER_STR() and their _INTO() variations to allow reading CO-RE-relocatable kernel data structures from the user-space. One of such cases is reading input arguments of syscalls, while reaping the benefits of CO-RE relocations w.r.t. handling 32/64 bit conversions and handling missing/new fields in UAPI data structs. Suggested-by: Gilad Reti Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/bpf_core_read.h | 98 +++++++++++++++++++++-------------- 1 file changed, 59 insertions(+), 39 deletions(-) diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index bbcefb3ff5a5..db0c735ceb53 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -195,17 +195,20 @@ enum bpf_enum_value_kind { * (local) BTF, used to record relocation. */ #define bpf_core_read(dst, sz, src) \ - bpf_probe_read_kernel(dst, sz, \ - (const void *)__builtin_preserve_access_index(src)) + bpf_probe_read_kernel(dst, sz, (const void *)__builtin_preserve_access_index(src)) +#define bpf_core_read_user(dst, sz, src) \ + bpf_probe_read_user(dst, sz, (const void *)__builtin_preserve_access_index(src)) /* * bpf_core_read_str() is a thin wrapper around bpf_probe_read_str() * additionally emitting BPF CO-RE field relocation for specified source * argument. */ #define bpf_core_read_str(dst, sz, src) \ - bpf_probe_read_kernel_str(dst, sz, \ - (const void *)__builtin_preserve_access_index(src)) + bpf_probe_read_kernel_str(dst, sz, (const void *)__builtin_preserve_access_index(src)) + +#define bpf_core_read_user_str(dst, sz, src) \ + bpf_probe_read_user_str(dst, sz, (const void *)__builtin_preserve_access_index(src)) #define ___concat(a, b) a ## b #define ___apply(fn, n) ___concat(fn, n) @@ -264,30 +267,29 @@ enum bpf_enum_value_kind { read_fn((void *)(dst), sizeof(*(dst)), &((src_type)(src))->accessor) /* "recursively" read a sequence of inner pointers using local __t var */ -#define ___rd_first(src, a) ___read(bpf_core_read, &__t, ___type(src), src, a); -#define ___rd_last(...) \ - ___read(bpf_core_read, &__t, \ - ___type(___nolast(__VA_ARGS__)), __t, ___last(__VA_ARGS__)); -#define ___rd_p1(...) const void *__t; ___rd_first(__VA_ARGS__) -#define ___rd_p2(...) ___rd_p1(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) -#define ___rd_p3(...) ___rd_p2(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) -#define ___rd_p4(...) ___rd_p3(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) -#define ___rd_p5(...) ___rd_p4(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) -#define ___rd_p6(...) ___rd_p5(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) -#define ___rd_p7(...) ___rd_p6(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) -#define ___rd_p8(...) ___rd_p7(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) -#define ___rd_p9(...) ___rd_p8(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) -#define ___read_ptrs(src, ...) \ - ___apply(___rd_p, ___narg(__VA_ARGS__))(src, __VA_ARGS__) - -#define ___core_read0(fn, dst, src, a) \ +#define ___rd_first(fn, src, a) ___read(fn, &__t, ___type(src), src, a); +#define ___rd_last(fn, ...) \ + ___read(fn, &__t, ___type(___nolast(__VA_ARGS__)), __t, ___last(__VA_ARGS__)); +#define ___rd_p1(fn, ...) const void *__t; ___rd_first(fn, __VA_ARGS__) +#define ___rd_p2(fn, ...) ___rd_p1(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) +#define ___rd_p3(fn, ...) ___rd_p2(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) +#define ___rd_p4(fn, ...) ___rd_p3(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) +#define ___rd_p5(fn, ...) ___rd_p4(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) +#define ___rd_p6(fn, ...) ___rd_p5(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) +#define ___rd_p7(fn, ...) ___rd_p6(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) +#define ___rd_p8(fn, ...) ___rd_p7(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) +#define ___rd_p9(fn, ...) ___rd_p8(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) +#define ___read_ptrs(fn, src, ...) \ + ___apply(___rd_p, ___narg(__VA_ARGS__))(fn, src, __VA_ARGS__) + +#define ___core_read0(fn, fn_ptr, dst, src, a) \ ___read(fn, dst, ___type(src), src, a); -#define ___core_readN(fn, dst, src, ...) \ - ___read_ptrs(src, ___nolast(__VA_ARGS__)) \ +#define ___core_readN(fn, fn_ptr, dst, src, ...) \ + ___read_ptrs(fn_ptr, src, ___nolast(__VA_ARGS__)) \ ___read(fn, dst, ___type(src, ___nolast(__VA_ARGS__)), __t, \ ___last(__VA_ARGS__)); -#define ___core_read(fn, dst, src, a, ...) \ - ___apply(___core_read, ___empty(__VA_ARGS__))(fn, dst, \ +#define ___core_read(fn, fn_ptr, dst, src, a, ...) \ + ___apply(___core_read, ___empty(__VA_ARGS__))(fn, fn_ptr, dst, \ src, a, ##__VA_ARGS__) /* @@ -295,20 +297,32 @@ enum bpf_enum_value_kind { * BPF_CORE_READ(), in which final field is read into user-provided storage. * See BPF_CORE_READ() below for more details on general usage. */ -#define BPF_CORE_READ_INTO(dst, src, a, ...) \ - ({ \ - ___core_read(bpf_core_read, dst, (src), a, ##__VA_ARGS__) \ - }) +#define BPF_CORE_READ_INTO(dst, src, a, ...) ({ \ + ___core_read(bpf_core_read, bpf_core_read, \ + dst, (src), a, ##__VA_ARGS__) \ +}) + +/* Variant of BPF_CORE_READ_INTO() for reading from user-space memory */ +#define BPF_CORE_READ_USER_INTO(dst, src, a, ...) ({ \ + ___core_read(bpf_core_read_user, bpf_core_read_user, \ + dst, (src), a, ##__VA_ARGS__) \ +}) /* * BPF_CORE_READ_STR_INTO() does same "pointer chasing" as * BPF_CORE_READ() for intermediate pointers, but then executes (and returns * corresponding error code) bpf_core_read_str() for final string read. */ -#define BPF_CORE_READ_STR_INTO(dst, src, a, ...) \ - ({ \ - ___core_read(bpf_core_read_str, dst, (src), a, ##__VA_ARGS__)\ - }) +#define BPF_CORE_READ_STR_INTO(dst, src, a, ...) ({ \ + ___core_read(bpf_core_read_str, bpf_core_read, \ + dst, (src), a, ##__VA_ARGS__) \ +}) + +/* Variant of BPF_CORE_READ_STR_INTO() for reading from user-space memory */ +#define BPF_CORE_READ_USER_STR_INTO(dst, src, a, ...) ({ \ + ___core_read(bpf_core_read_user_str, bpf_core_read_user, \ + dst, (src), a, ##__VA_ARGS__) \ +}) /* * BPF_CORE_READ() is used to simplify BPF CO-RE relocatable read, especially @@ -334,12 +348,18 @@ enum bpf_enum_value_kind { * N.B. Only up to 9 "field accessors" are supported, which should be more * than enough for any practical purpose. */ -#define BPF_CORE_READ(src, a, ...) \ - ({ \ - ___type((src), a, ##__VA_ARGS__) __r; \ - BPF_CORE_READ_INTO(&__r, (src), a, ##__VA_ARGS__); \ - __r; \ - }) +#define BPF_CORE_READ(src, a, ...) ({ \ + ___type((src), a, ##__VA_ARGS__) __r; \ + BPF_CORE_READ_INTO(&__r, (src), a, ##__VA_ARGS__); \ + __r; \ +}) + +/* Variant of BPF_CORE_READ() for reading from user-space memory */ +#define BPF_CORE_READ_USER(src, a, ...) ({ \ + ___type((src), a, ##__VA_ARGS__) __r; \ + BPF_CORE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__); \ + __r; \ +}) #endif From patchwork Fri Dec 18 23:56:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 345882 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 58E84C3527A for ; Fri, 18 Dec 2020 23:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3EFB123A7B for ; Fri, 18 Dec 2020 23:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726203AbgLRX5J convert rfc822-to-8bit (ORCPT ); Fri, 18 Dec 2020 18:57:09 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:28360 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726089AbgLRX5J (ORCPT ); Fri, 18 Dec 2020 18:57:09 -0500 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 0BINsC2t013124 for ; Fri, 18 Dec 2020 15:56:29 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 35gxe5jqc9-7 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 18 Dec 2020 15:56:28 -0800 Received: from intmgw001.08.frc2.facebook.com (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 15.1.1979.3; Fri, 18 Dec 2020 15:56:25 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id DCD272ECB8FE; Fri, 18 Dec 2020 15:56:20 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH bpf-next 2/3] libbpf: add non-CO-RE variants of BPF_CORE_READ() macro family Date: Fri, 18 Dec 2020 15:56:13 -0800 Message-ID: <20201218235614.2284956-3-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201218235614.2284956-1-andrii@kernel.org> References: <20201218235614.2284956-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343, 18.0.737 definitions=2020-12-18_14:2020-12-18,2020-12-18 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 mlxscore=0 spamscore=0 clxscore=1034 priorityscore=1501 lowpriorityscore=0 mlxlogscore=582 adultscore=0 phishscore=0 bulkscore=0 suspectscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012180163 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org BPF_CORE_READ(), in addition to handling CO-RE relocations, also allows much nicer way to read data structures with nested pointers. Instead of writing a sequence of bpf_probe_read() calls to follow links, one can just write BPF_CORE_READ(a, b, c, d) to effectively do a->b->c->d read. This is a welcome ability when porting BCC code, which (in most cases) allows exactly the intuitive a->b->c->d variant. This patch adds non-CO-RE variants of BPF_CORE_READ() family of macros for cases where CO-RE is not supported (e.g., old kernels). In such cases, the property of shortening a sequence of bpf_probe_read()s to a simple BPF_PROBE_READ(a, b, c, d) invocation is still desirable, especially when porting BCC code to libbpf. Yet, no CO-RE relocation is going to be emitted. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/bpf_core_read.h | 38 +++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index db0c735ceb53..9456aabcb03a 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -308,6 +308,18 @@ enum bpf_enum_value_kind { dst, (src), a, ##__VA_ARGS__) \ }) +/* Non-CO-RE variant of BPF_CORE_READ_INTO() */ +#define BPF_PROBE_READ_INTO(dst, src, a, ...) ({ \ + ___core_read(bpf_probe_read, bpf_probe_read, \ + dst, (src), a, ##__VA_ARGS__) \ +}) + +/* Non-CO-RE variant of BPF_CORE_READ_USER_INTO() */ +#define BPF_PROBE_READ_USER_INTO(dst, src, a, ...) ({ \ + ___core_read(bpf_probe_read_user, bpf_probe_read_user, \ + dst, (src), a, ##__VA_ARGS__) \ +}) + /* * BPF_CORE_READ_STR_INTO() does same "pointer chasing" as * BPF_CORE_READ() for intermediate pointers, but then executes (and returns @@ -324,6 +336,18 @@ enum bpf_enum_value_kind { dst, (src), a, ##__VA_ARGS__) \ }) +/* Non-CO-RE variant of BPF_CORE_READ_STR_INTO() */ +#define BPF_PROBE_READ_STR_INTO(dst, src, a, ...) ({ \ + ___core_read(bpf_probe_read_str, bpf_probe_read, \ + dst, (src), a, ##__VA_ARGS__) \ +}) + +/* Non-CO-RE variant of BPF_CORE_READ_USER_STR_INTO() */ +#define BPF_PROBE_READ_USER_STR_INTO(dst, src, a, ...) ({ \ + ___core_read(bpf_probe_read_user_str, bpf_probe_read_user, \ + dst, (src), a, ##__VA_ARGS__) \ +}) + /* * BPF_CORE_READ() is used to simplify BPF CO-RE relocatable read, especially * when there are few pointer chasing steps. @@ -361,5 +385,19 @@ enum bpf_enum_value_kind { __r; \ }) +/* Non-CO-RE variant of BPF_CORE_READ() */ +#define BPF_PROBE_READ(src, a, ...) ({ \ + ___type((src), a, ##__VA_ARGS__) __r; \ + BPF_PROBE_READ_INTO(&__r, (src), a, ##__VA_ARGS__); \ + __r; \ +}) + +/* Non-CO-RE variant of BPF_CORE_READ_USER() */ +#define BPF_PROBE_READ_USER(src, a, ...) ({ \ + ___type((src), a, ##__VA_ARGS__) __r; \ + BPF_PROBE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__); \ + __r; \ +}) + #endif From patchwork Fri Dec 18 23:56:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 346183 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 27B54C3526E for ; Fri, 18 Dec 2020 23:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBFF623BAD for ; Fri, 18 Dec 2020 23:57:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726068AbgLRX5H convert rfc822-to-8bit (ORCPT ); Fri, 18 Dec 2020 18:57:07 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:48834 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725885AbgLRX5G (ORCPT ); Fri, 18 Dec 2020 18:57:06 -0500 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 0BINsC2n013124 for ; Fri, 18 Dec 2020 15:56:26 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 35gxe5jqc9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 18 Dec 2020 15:56:26 -0800 Received: from intmgw002.03.ash8.facebook.com (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 15.1.1979.3; Fri, 18 Dec 2020 15:56:25 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 0F2E52ECB8FE; Fri, 18 Dec 2020 15:56:23 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH bpf-next 3/3] selftests/bpf: add tests for user- and non-CO-RE BPF_CORE_READ() variants Date: Fri, 18 Dec 2020 15:56:14 -0800 Message-ID: <20201218235614.2284956-4-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201218235614.2284956-1-andrii@kernel.org> References: <20201218235614.2284956-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343, 18.0.737 definitions=2020-12-18_14:2020-12-18,2020-12-18 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 mlxscore=0 spamscore=0 clxscore=1034 priorityscore=1501 lowpriorityscore=0 mlxlogscore=999 adultscore=0 phishscore=0 bulkscore=0 suspectscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012180163 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Add selftests validating that newly added variations of BPF_CORE_READ(), for use with user-space addresses and for non-CO-RE reads, work as expected. Signed-off-by: Andrii Nakryiko --- .../bpf/prog_tests/core_read_macros.c | 64 +++++++++++++++++++ .../bpf/progs/test_core_read_macros.c | 51 +++++++++++++++ 2 files changed, 115 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/core_read_macros.c create mode 100644 tools/testing/selftests/bpf/progs/test_core_read_macros.c diff --git a/tools/testing/selftests/bpf/prog_tests/core_read_macros.c b/tools/testing/selftests/bpf/prog_tests/core_read_macros.c new file mode 100644 index 000000000000..96f5cf3c6fa2 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/core_read_macros.c @@ -0,0 +1,64 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Facebook */ + +#include + +struct callback_head { + struct callback_head *next; + void (*func)(struct callback_head *head); +}; + +/* ___shuffled flavor is just an illusion for BPF code, it doesn't really + * exist and user-space needs to provide data in the memory layout that + * matches callback_head. We just defined ___shuffled flavor to make it easier + * to work with the skeleton + */ +struct callback_head___shuffled { + struct callback_head___shuffled *next; + void (*func)(struct callback_head *head); +}; + +#include "test_core_read_macros.skel.h" + +void test_core_read_macros(void) +{ + int duration = 0, err; + struct test_core_read_macros* skel; + struct test_core_read_macros__bss *bss; + struct callback_head u_probe_in; + struct callback_head___shuffled u_core_in; + + skel = test_core_read_macros__open_and_load(); + if (CHECK(!skel, "skel_open", "failed to open skeleton\n")) + return; + bss = skel->bss; + bss->my_pid = getpid(); + + /* next pointers have to be set from the kernel side */ + bss->k_probe_in.func = (void *)(long)0x1234; + bss->k_core_in.func = (void *)(long)0xabcd; + + u_probe_in.next = &u_probe_in; + u_probe_in.func = (void *)(long)0x5678; + bss->u_probe_in = &u_probe_in; + + u_core_in.next = &u_core_in; + u_core_in.func = (void *)(long)0xdbca; + bss->u_core_in = &u_core_in; + + err = test_core_read_macros__attach(skel); + if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err)) + goto cleanup; + + /* trigger tracepoint */ + usleep(1); + + ASSERT_EQ(bss->k_probe_out, 0x1234, "k_probe_out"); + ASSERT_EQ(bss->k_core_out, 0xabcd, "k_core_out"); + + ASSERT_EQ(bss->u_probe_out, 0x5678, "u_probe_out"); + ASSERT_EQ(bss->u_core_out, 0xdbca, "u_core_out"); + +cleanup: + test_core_read_macros__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_core_read_macros.c b/tools/testing/selftests/bpf/progs/test_core_read_macros.c new file mode 100644 index 000000000000..50054af0a928 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_core_read_macros.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook + +#include "vmlinux.h" +#include +#include + +char _license[] SEC("license") = "GPL"; + +/* shuffled layout for relocatable (CO-RE) reads */ +struct callback_head___shuffled { + void (*func)(struct callback_head___shuffled *head); + struct callback_head___shuffled *next; +}; + +struct callback_head k_probe_in = {}; +struct callback_head___shuffled k_core_in = {}; + +struct callback_head *u_probe_in = 0; +struct callback_head___shuffled *u_core_in = 0; + +long k_probe_out = 0; +long u_probe_out = 0; + +long k_core_out = 0; +long u_core_out = 0; + +int my_pid = 0; + +SEC("raw_tracepoint/sys_enter") +int handler(void *ctx) +{ + int pid = bpf_get_current_pid_tgid() >> 32; + + if (my_pid != pid) + return 0; + + /* next pointers for kernel address space have to be initialized from + * BPF side, user-space mmaped addresses are stil user-space addresses + */ + k_probe_in.next = &k_probe_in; + __builtin_preserve_access_index(({k_core_in.next = &k_core_in;})); + + k_probe_out = (long)BPF_PROBE_READ(&k_probe_in, next, next, func); + k_core_out = (long)BPF_CORE_READ(&k_core_in, next, next, func); + u_probe_out = (long)BPF_PROBE_READ_USER(u_probe_in, next, next, func); + u_core_out = (long)BPF_CORE_READ_USER(u_core_in, next, next, func); + + return 0; +} +