From patchwork Fri Jun 12 19:45:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1308489 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=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject 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.a=rsa-sha256 header.s=facebook header.b=AqVwM/Jp; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49kB5l2wHVz9s1x for ; Sat, 13 Jun 2020 05:45:15 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726269AbgFLTpN (ORCPT ); Fri, 12 Jun 2020 15:45:13 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:37546 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726268AbgFLTpN (ORCPT ); Fri, 12 Jun 2020 15:45:13 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 05CJhetd021928 for ; Fri, 12 Jun 2020 12:45:12 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=Qp/DEnKtEcycXYg1548mpTkaEBJQRsSgCs89Jo2VQD8=; b=AqVwM/JpVJGga8K8majH0MsZWC+QAPF2T1f4bw08YH7DCIBDqf/f70FIdNY0gZFJ7wbG obgKTPfOZZszL6LBIS6P2BCsAY7wIPdD5i5G5jWDSeU41v+aArnSzG7o7DcK1lE7W4Zn xH771qgRoKw7gjvMPpB1P08t6ZnsPzumZlY= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 31k322mbc7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 12 Jun 2020 12:45:10 -0700 Received: from intmgw001.08.frc2.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:11d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 12 Jun 2020 12:45:09 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 1B2FF2EC1E9F; Fri, 12 Jun 2020 12:45:07 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Andrii Nakryiko Smtp-Origin-Hostname: devbig012.ftw2.facebook.com To: , , , CC: , , Andrii Nakryiko Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf] libbpf: support pre-initializing .bss global variables Date: Fri, 12 Jun 2020 12:45:04 -0700 Message-ID: <20200612194504.557844-1-andriin@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.687 definitions=2020-06-12_16:2020-06-12,2020-06-12 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 cotscore=-2147483648 priorityscore=1501 suspectscore=0 impostorscore=0 mlxlogscore=999 phishscore=0 bulkscore=0 malwarescore=0 adultscore=0 mlxscore=0 clxscore=1015 lowpriorityscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006120143 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Remove invalid assumption in libbpf that .bss map doesn't have to be updated in kernel. With addition of skeleton and memory-mapped initialization image, .bss doesn't have to be all zeroes when BPF map is created, because user-code might have initialized those variables from user-space. Fixes: eba9c5f498a1 ("libbpf: Refactor global data map initialization") Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 4 -- .../selftests/bpf/prog_tests/skeleton.c | 45 ++++++++++++++++--- .../selftests/bpf/progs/test_skeleton.c | 19 ++++++-- 3 files changed, 55 insertions(+), 13 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 7f01be2b88b8..477c679ed945 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3564,10 +3564,6 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) char *cp, errmsg[STRERR_BUFSIZE]; int err, zero = 0; - /* kernel already zero-initializes .bss map. */ - if (map_type == LIBBPF_MAP_BSS) - return 0; - err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0); if (err) { err = -errno; diff --git a/tools/testing/selftests/bpf/prog_tests/skeleton.c b/tools/testing/selftests/bpf/prog_tests/skeleton.c index 9264a2736018..fa153cf67b1b 100644 --- a/tools/testing/selftests/bpf/prog_tests/skeleton.c +++ b/tools/testing/selftests/bpf/prog_tests/skeleton.c @@ -15,6 +15,8 @@ void test_skeleton(void) int duration = 0, err; struct test_skeleton* skel; struct test_skeleton__bss *bss; + struct test_skeleton__data *data; + struct test_skeleton__rodata *rodata; struct test_skeleton__kconfig *kcfg; skel = test_skeleton__open(); @@ -24,13 +26,45 @@ void test_skeleton(void) if (CHECK(skel->kconfig, "skel_kconfig", "kconfig is mmaped()!\n")) goto cleanup; + bss = skel->bss; + data = skel->data; + rodata = skel->rodata; + + /* validate values are pre-initialized correctly */ + CHECK(data->in1 != -1, "in1", "got %d != exp %d\n", data->in1, -1); + CHECK(data->out1 != -1, "out1", "got %d != exp %d\n", data->out1, -1); + CHECK(data->in2 != -1, "in2", "got %lld != exp %lld\n", data->in2, -1LL); + CHECK(data->out2 != -1, "out2", "got %lld != exp %lld\n", data->out2, -1LL); + + CHECK(bss->in3 != 0, "in3", "got %d != exp %d\n", bss->in3, 0); + CHECK(bss->out3 != 0, "out3", "got %d != exp %d\n", bss->out3, 0); + CHECK(bss->in4 != 0, "in4", "got %lld != exp %lld\n", bss->in4, 0LL); + CHECK(bss->out4 != 0, "out4", "got %lld != exp %lld\n", bss->out4, 0LL); + + CHECK(rodata->in6 != 0, "in6", "got %d != exp %d\n", rodata->in6, 0); + CHECK(bss->out6 != 0, "out6", "got %d != exp %d\n", bss->out6, 0); + + /* validate we can pre-setup global variables, even in .bss */ + data->in1 = 10; + data->in2 = 11; + bss->in3 = 12; + bss->in4 = 13; + rodata->in6 = 14; + err = test_skeleton__load(skel); if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err)) goto cleanup; - bss = skel->bss; - bss->in1 = 1; - bss->in2 = 2; + /* validate pre-setup values are still there */ + CHECK(data->in1 != 10, "in1", "got %d != exp %d\n", data->in1, 10); + CHECK(data->in2 != 11, "in2", "got %lld != exp %lld\n", data->in2, 11LL); + CHECK(bss->in3 != 12, "in3", "got %d != exp %d\n", bss->in3, 12); + CHECK(bss->in4 != 13, "in4", "got %lld != exp %lld\n", bss->in4, 13LL); + CHECK(rodata->in6 != 14, "in6", "got %d != exp %d\n", rodata->in6, 14); + + /* now set new values and attach to get them into outX variables */ + data->in1 = 1; + data->in2 = 2; bss->in3 = 3; bss->in4 = 4; bss->in5.a = 5; @@ -44,14 +78,15 @@ void test_skeleton(void) /* trigger tracepoint */ usleep(1); - CHECK(bss->out1 != 1, "res1", "got %d != exp %d\n", bss->out1, 1); - CHECK(bss->out2 != 2, "res2", "got %lld != exp %d\n", bss->out2, 2); + CHECK(data->out1 != 1, "res1", "got %d != exp %d\n", data->out1, 1); + CHECK(data->out2 != 2, "res2", "got %lld != exp %d\n", data->out2, 2); CHECK(bss->out3 != 3, "res3", "got %d != exp %d\n", (int)bss->out3, 3); CHECK(bss->out4 != 4, "res4", "got %lld != exp %d\n", bss->out4, 4); CHECK(bss->handler_out5.a != 5, "res5", "got %d != exp %d\n", bss->handler_out5.a, 5); CHECK(bss->handler_out5.b != 6, "res6", "got %lld != exp %d\n", bss->handler_out5.b, 6); + CHECK(bss->out6 != 14, "res7", "got %d != exp %d\n", bss->out6, 14); CHECK(bss->bpf_syscall != kcfg->CONFIG_BPF_SYSCALL, "ext1", "got %d != exp %d\n", bss->bpf_syscall, kcfg->CONFIG_BPF_SYSCALL); diff --git a/tools/testing/selftests/bpf/progs/test_skeleton.c b/tools/testing/selftests/bpf/progs/test_skeleton.c index de03a90f78ca..77ae86f44db5 100644 --- a/tools/testing/selftests/bpf/progs/test_skeleton.c +++ b/tools/testing/selftests/bpf/progs/test_skeleton.c @@ -10,16 +10,26 @@ struct s { long long b; } __attribute__((packed)); -int in1 = 0; -long long in2 = 0; +/* .data section */ +int in1 = -1; +long long in2 = -1; + +/* .bss section */ char in3 = '\0'; long long in4 __attribute__((aligned(64))) = 0; struct s in5 = {}; -long long out2 = 0; +/* .rodata section */ +const volatile int in6 = 0; + +/* .data section */ +int out1 = -1; +long long out2 = -1; + +/* .bss section */ char out3 = 0; long long out4 = 0; -int out1 = 0; +int out6 = 0; extern bool CONFIG_BPF_SYSCALL __kconfig; extern int LINUX_KERNEL_VERSION __kconfig; @@ -36,6 +46,7 @@ int handler(const void *ctx) out3 = in3; out4 = in4; out5 = in5; + out6 = in6; bpf_syscall = CONFIG_BPF_SYSCALL; kern_ver = LINUX_KERNEL_VERSION;