From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D63184AF81 for ; Wed, 20 Dec 2023 23:31:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3BKN2hbB029798 for ; Wed, 20 Dec 2023 15:31:51 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3v49kfr4cp-6 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 20 Dec 2023 15:31:51 -0800 Received: from twshared10507.42.prn1.facebook.com (2620:10d:c0a8:1c::11) by mail.thefacebook.com (2620:10d:c0a8:83::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.34; Wed, 20 Dec 2023 15:31:48 -0800 Received: by devbig019.vll3.facebook.com (Postfix, from userid 137359) id C50533D865073; Wed, 20 Dec 2023 15:31:39 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH bpf-next 5/8] libbpf: move exception callbacks assignment logic into relocation step Date: Wed, 20 Dec 2023 15:31:24 -0800 Message-ID: <20231220233127.1990417-6-andrii@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231220233127.1990417-1-andrii@kernel.org> References: <20231220233127.1990417-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-GUID: 6VsXcge-9_pkXJm-V6viiZxAopGdBNLR X-Proofpoint-ORIG-GUID: 6VsXcge-9_pkXJm-V6viiZxAopGdBNLR X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-20_13,2023-12-20_01,2023-05-22_02 Move the logic of finding and assigning exception callback indices from BTF sanitization step to program relocations step, which seems more logical and will unblock moving BTF loading to after relocation step. Exception callbacks discovery and assignment has no dependency on BTF being loaded into the kernel, it only uses BTF information. It does need to happen before subprogram relocations happen, though. Which is why the split. No functional changes. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 165 +++++++++++++++++++++-------------------- 1 file changed, 85 insertions(+), 80 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 98bec2f5fe39..26a0869626bf 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3182,86 +3182,6 @@ static int bpf_object__sanitize_and_load_btf(struc= t bpf_object *obj) } } =20 - if (!kernel_supports(obj, FEAT_BTF_DECL_TAG)) - goto skip_exception_cb; - for (i =3D 0; i < obj->nr_programs; i++) { - struct bpf_program *prog =3D &obj->programs[i]; - int j, k, n; - - if (prog_is_subprog(obj, prog)) - continue; - n =3D btf__type_cnt(obj->btf); - for (j =3D 1; j < n; j++) { - const char *str =3D "exception_callback:", *name; - size_t len =3D strlen(str); - struct btf_type *t; - - t =3D btf_type_by_id(obj->btf, j); - if (!btf_is_decl_tag(t) || btf_decl_tag(t)->component_idx !=3D -1) - continue; - - name =3D btf__str_by_offset(obj->btf, t->name_off); - if (strncmp(name, str, len)) - continue; - - t =3D btf_type_by_id(obj->btf, t->type); - if (!btf_is_func(t) || btf_func_linkage(t) !=3D BTF_FUNC_GLOBAL) { - pr_warn("prog '%s': exception_callback: decl tag not applied = to the main program\n", - prog->name); - return -EINVAL; - } - if (strcmp(prog->name, btf__str_by_offset(obj->btf, t->name_off))) - continue; - /* Multiple callbacks are specified for the same prog, - * the verifier will eventually return an error for this - * case, hence simply skip appending a subprog. - */ - if (prog->exception_cb_idx >=3D 0) { - prog->exception_cb_idx =3D -1; - break; - } - - name +=3D len; - if (str_is_empty(name)) { - pr_warn("prog '%s': exception_callback: decl tag contains emp= ty value\n", - prog->name); - return -EINVAL; - } - - for (k =3D 0; k < obj->nr_programs; k++) { - struct bpf_program *subprog =3D &obj->programs[k]; - - if (!prog_is_subprog(obj, subprog)) - continue; - if (strcmp(name, subprog->name)) - continue; - /* Enforce non-hidden, as from verifier point of - * view it expects global functions, whereas the - * mark_btf_static fixes up linkage as static. - */ - if (!subprog->sym_global || subprog->mark_btf_static) { - pr_warn("prog '%s': exception callback %s must be a global non-hidd= en function\n", - prog->name, subprog->name); - return -EINVAL; - } - /* Let's see if we already saw a static exception callback with the = same name */ - if (prog->exception_cb_idx >=3D 0) { - pr_warn("prog '%s': multiple subprogs with same name as exception c= allback '%s'\n", - prog->name, subprog->name); - return -EINVAL; - } - prog->exception_cb_idx =3D k; - break; - } - - if (prog->exception_cb_idx >=3D 0) - continue; - pr_warn("prog '%s': cannot find exception callback '%s'\n", prog->nam= e, name); - return -ENOENT; - } - } -skip_exception_cb: - sanitize =3D btf_needs_sanitization(obj); if (sanitize) { const void *raw_data; @@ -6648,6 +6568,88 @@ static void bpf_object__sort_relos(struct bpf_obje= ct *obj) } } =20 +static int bpf_prog_assign_exc_cb(struct bpf_object *obj, struct bpf_pro= gram *prog) +{ + const char *str =3D "exception_callback:"; + size_t pfx_len =3D strlen(str); + int i, j, n; + + if (!obj->btf || !kernel_supports(obj, FEAT_BTF_DECL_TAG)) + return 0; + + n =3D btf__type_cnt(obj->btf); + for (i =3D 1; i < n; i++) { + const char *name; + struct btf_type *t; + + t =3D btf_type_by_id(obj->btf, i); + if (!btf_is_decl_tag(t) || btf_decl_tag(t)->component_idx !=3D -1) + continue; + + name =3D btf__str_by_offset(obj->btf, t->name_off); + if (strncmp(name, str, pfx_len) !=3D 0) + continue; + + t =3D btf_type_by_id(obj->btf, t->type); + if (!btf_is_func(t) || btf_func_linkage(t) !=3D BTF_FUNC_GLOBAL) { + pr_warn("prog '%s': exception_callback: decl tag not applied t= o the main program\n", + prog->name); + return -EINVAL; + } + if (strcmp(prog->name, btf__str_by_offset(obj->btf, t->name_off)) !=3D= 0) + continue; + /* Multiple callbacks are specified for the same prog, + * the verifier will eventually return an error for this + * case, hence simply skip appending a subprog. + */ + if (prog->exception_cb_idx >=3D 0) { + prog->exception_cb_idx =3D -1; + break; + } + + name +=3D pfx_len; + if (str_is_empty(name)) { + pr_warn("prog '%s': exception_callback: decl tag contains empt= y value\n", + prog->name); + return -EINVAL; + } + + for (j =3D 0; j < obj->nr_programs; j++) { + struct bpf_program *subprog =3D &obj->programs[j]; + + if (!prog_is_subprog(obj, subprog)) + continue; + if (strcmp(name, subprog->name) !=3D 0) + continue; + /* Enforce non-hidden, as from verifier point of + * view it expects global functions, whereas the + * mark_btf_static fixes up linkage as static. + */ + if (!subprog->sym_global || subprog->mark_btf_static) { + pr_warn("prog '%s': exception callback %s must be a global non-hidde= n function\n", + prog->name, subprog->name); + return -EINVAL; + } + /* Let's see if we already saw a static exception callback with the s= ame name */ + if (prog->exception_cb_idx >=3D 0) { + pr_warn("prog '%s': multiple subprogs with same name as exception ca= llback '%s'\n", + prog->name, subprog->name); + return -EINVAL; + } + prog->exception_cb_idx =3D j; + break; + } + + if (prog->exception_cb_idx >=3D 0) + continue; + + pr_warn("prog '%s': cannot find exception callback '%s'\n", prog->name= , name); + return -ENOENT; + } + + return 0; +} + static int bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) { @@ -6708,6 +6710,9 @@ bpf_object__relocate(struct bpf_object *obj, const = char *targ_btf_path) return err; } =20 + err =3D bpf_prog_assign_exc_cb(obj, prog); + if (err) + return err; /* Now, also append exception callback if it has not been done already= . */ if (prog->exception_cb_idx >=3D 0) { struct bpf_program *subprog =3D &obj->programs[prog->exception_cb_idx= ]; --=20 2.34.1