From patchwork Tue Feb 14 21:28:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ilya Leoshkevich X-Patchwork-Id: 13140875 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C41E2C61DA4 for ; Tue, 14 Feb 2023 21:30:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232519AbjBNVab (ORCPT ); Tue, 14 Feb 2023 16:30:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232637AbjBNVaa (ORCPT ); Tue, 14 Feb 2023 16:30:30 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5599976BE for ; Tue, 14 Feb 2023 13:30:02 -0800 (PST) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 31EKg1md010845; Tue, 14 Feb 2023 21:28:20 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=LCMOo/iIotRwDHgwSU5zc0kBBex77OX8CEJHBHWVYWU=; b=QnrpvjOQ5UOb4a6i5+NuEt5wSBTV9oGgam5g1RP6fX59wjcKZSufj8R+y1l5hzNTl1Tu wqUf9r0gwGmYwIza7knqEOwQhDtIH+r+hlAazP96JGrNVJb1ucRLB0O7iV5oxhZaynYO TFB0K7Le7Zbq2ggEdxoZTsyZJBNpHbpgE1p8GI35uM93ZimWCa5b0iIxpAsdySUMZwmv N0XSR+qq/JkfaHEFaLQ5AWvE1tNxk3q6k1VeBrs8SGyy/w2Bbo7hN232AlJYkjqpZmR0 H4Ot1xM3cS5jQmKtQe+Fv/SPPd8MF3DbDNV5RdVXpDZuUK1qH6DZfuir0K2KSPEs0YTk Tg== Received: from ppma04ams.nl.ibm.com (63.31.33a9.ip4.static.sl-reverse.com [169.51.49.99]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3nrhjf9s6m-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 14 Feb 2023 21:28:20 +0000 Received: from pps.filterd (ppma04ams.nl.ibm.com [127.0.0.1]) by ppma04ams.nl.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 31EIYTIK010698; Tue, 14 Feb 2023 21:28:18 GMT Received: from smtprelay03.fra02v.mail.ibm.com ([9.218.2.224]) by ppma04ams.nl.ibm.com (PPS) with ESMTPS id 3np2n6vhgs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 14 Feb 2023 21:28:18 +0000 Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay03.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 31ELSET538339064 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 14 Feb 2023 21:28:14 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 791E420043; Tue, 14 Feb 2023 21:28:14 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C92FD20040; Tue, 14 Feb 2023 21:28:13 +0000 (GMT) Received: from heavy.lan (unknown [9.171.47.108]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 14 Feb 2023 21:28:13 +0000 (GMT) From: Ilya Leoshkevich To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Jiri Olsa , Ilya Leoshkevich Subject: [PATCH RFC bpf-next 1/1] bpf: Support 64-bit pointers to kfuncs Date: Tue, 14 Feb 2023 22:28:09 +0100 Message-Id: <20230214212809.242632-2-iii@linux.ibm.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230214212809.242632-1-iii@linux.ibm.com> References: <20230214212809.242632-1-iii@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: bCr3mxusApphKm1Far5CtP_1wRhb7BWK X-Proofpoint-ORIG-GUID: bCr3mxusApphKm1Far5CtP_1wRhb7BWK X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.170.22 definitions=2023-02-14_15,2023-02-14_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 adultscore=0 malwarescore=0 spamscore=0 clxscore=1015 mlxlogscore=999 impostorscore=0 bulkscore=0 phishscore=0 suspectscore=0 lowpriorityscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2302140182 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC test_ksyms_module fails to emit a kfunc call targeting a module on s390x, because the verifier stores the difference between kfunc address and __bpf_call_base in bpf_insn.imm, which is s32, and modules are roughly (1 << 42) bytes away from the kernel on s390x. Fix by keeping BTF id in bpf_insn.imm for BPF_PSEUDO_KFUNC_CALLs, and storing the absolute address in bpf_kfunc_desc, which JITs retrieve as usual by calling bpf_jit_get_func_addr(). This also fixes the problem with XDP metadata functions outlined in the description of commit 63d7b53ab59f ("s390/bpf: Implement bpf_jit_supports_kfunc_call()") by replacing address lookups with BTF id lookups. This eliminates the inconsistency between "abstract" XDP metadata functions' BTF ids and their concrete addresses. Signed-off-by: Ilya Leoshkevich --- include/linux/bpf.h | 2 ++ kernel/bpf/core.c | 23 ++++++++++--- kernel/bpf/verifier.c | 79 +++++++++++++------------------------------ 3 files changed, 45 insertions(+), 59 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index be34f7deb6c3..83ce94d11484 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2227,6 +2227,8 @@ bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog); const struct btf_func_model * bpf_jit_find_kfunc_model(const struct bpf_prog *prog, const struct bpf_insn *insn); +int bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id, u16 offset, + u8 **func_addr); struct bpf_core_ctx { struct bpf_verifier_log *log; const struct btf *btf; diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 3390961c4e10..a42382afe333 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1185,10 +1185,12 @@ int bpf_jit_get_func_addr(const struct bpf_prog *prog, { s16 off = insn->off; s32 imm = insn->imm; + bool fixed; u8 *addr; + int err; - *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; - if (!*func_addr_fixed) { + switch (insn->src_reg) { + case BPF_PSEUDO_CALL: /* Place-holder address till the last pass has collected * all addresses for JITed subprograms in which case we * can pick them up from prog->aux. @@ -1200,16 +1202,29 @@ int bpf_jit_get_func_addr(const struct bpf_prog *prog, addr = (u8 *)prog->aux->func[off]->bpf_func; else return -EINVAL; - } else { + fixed = false; + break; + case 0: /* Address of a BPF helper call. Since part of the core * kernel, it's always at a fixed location. __bpf_call_base * and the helper with imm relative to it are both in core * kernel. */ addr = (u8 *)__bpf_call_base + imm; + fixed = true; + break; + case BPF_PSEUDO_KFUNC_CALL: + err = bpf_get_kfunc_addr(prog, imm, off, &addr); + if (err) + return err; + fixed = true; + break; + default: + return -EINVAL; } - *func_addr = (unsigned long)addr; + *func_addr_fixed = fixed; + *func_addr = addr; return 0; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 21e08c111702..aea59974f0d6 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2115,8 +2115,8 @@ static int add_subprog(struct bpf_verifier_env *env, int off) struct bpf_kfunc_desc { struct btf_func_model func_model; u32 func_id; - s32 imm; u16 offset; + unsigned long addr; }; struct bpf_kfunc_btf { @@ -2166,6 +2166,19 @@ find_kfunc_desc(const struct bpf_prog *prog, u32 func_id, u16 offset) sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off); } +int bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id, u16 offset, + u8 **func_addr) +{ + const struct bpf_kfunc_desc *desc; + + desc = find_kfunc_desc(prog, func_id, offset); + if (WARN_ON_ONCE(!desc)) + return -EINVAL; + + *func_addr = (u8 *)desc->addr; + return 0; +} + static struct btf *__find_kfunc_desc_btf(struct bpf_verifier_env *env, s16 offset) { @@ -2261,8 +2274,8 @@ static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset) struct bpf_kfunc_desc *desc; const char *func_name; struct btf *desc_btf; - unsigned long call_imm; unsigned long addr; + void *xdp_kfunc; int err; prog_aux = env->prog->aux; @@ -2346,24 +2359,21 @@ static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset) return -EINVAL; } - call_imm = BPF_CALL_IMM(addr); - /* Check whether or not the relative offset overflows desc->imm */ - if ((unsigned long)(s32)call_imm != call_imm) { - verbose(env, "address of kernel function %s is out of range\n", - func_name); - return -EINVAL; - } - if (bpf_dev_bound_kfunc_id(func_id)) { err = bpf_dev_bound_kfunc_check(&env->log, prog_aux); if (err) return err; + + xdp_kfunc = bpf_dev_bound_resolve_kfunc(env->prog, func_id); + if (xdp_kfunc) + addr = (unsigned long)xdp_kfunc; + /* fallback to default kfunc when not supported by netdev */ } desc = &tab->descs[tab->nr_descs++]; desc->func_id = func_id; - desc->imm = call_imm; desc->offset = offset; + desc->addr = addr; err = btf_distill_func_proto(&env->log, desc_btf, func_proto, func_name, &desc->func_model); @@ -2373,30 +2383,6 @@ static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset) return err; } -static int kfunc_desc_cmp_by_imm(const void *a, const void *b) -{ - const struct bpf_kfunc_desc *d0 = a; - const struct bpf_kfunc_desc *d1 = b; - - if (d0->imm > d1->imm) - return 1; - else if (d0->imm < d1->imm) - return -1; - return 0; -} - -static void sort_kfunc_descs_by_imm(struct bpf_prog *prog) -{ - struct bpf_kfunc_desc_tab *tab; - - tab = prog->aux->kfunc_tab; - if (!tab) - return; - - sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]), - kfunc_desc_cmp_by_imm, NULL); -} - bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog) { return !!prog->aux->kfunc_tab; @@ -2407,14 +2393,15 @@ bpf_jit_find_kfunc_model(const struct bpf_prog *prog, const struct bpf_insn *insn) { const struct bpf_kfunc_desc desc = { - .imm = insn->imm, + .func_id = insn->imm, + .offset = insn->off, }; const struct bpf_kfunc_desc *res; struct bpf_kfunc_desc_tab *tab; tab = prog->aux->kfunc_tab; res = bsearch(&desc, tab->descs, tab->nr_descs, - sizeof(tab->descs[0]), kfunc_desc_cmp_by_imm); + sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off); return res ? &res->func_model : NULL; } @@ -16251,7 +16238,6 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, struct bpf_insn *insn_buf, int insn_idx, int *cnt) { const struct bpf_kfunc_desc *desc; - void *xdp_kfunc; if (!insn->imm) { verbose(env, "invalid kernel function call not eliminated in verifier pass\n"); @@ -16259,20 +16245,6 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, } *cnt = 0; - - if (bpf_dev_bound_kfunc_id(insn->imm)) { - xdp_kfunc = bpf_dev_bound_resolve_kfunc(env->prog, insn->imm); - if (xdp_kfunc) { - insn->imm = BPF_CALL_IMM(xdp_kfunc); - return 0; - } - - /* fallback to default kfunc when not supported by netdev */ - } - - /* insn->imm has the btf func_id. Replace it with - * an address (relative to __bpf_call_base). - */ desc = find_kfunc_desc(env->prog, insn->imm, insn->off); if (!desc) { verbose(env, "verifier internal error: kernel function descriptor not found for func_id %u\n", @@ -16280,7 +16252,6 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, return -EFAULT; } - insn->imm = desc->imm; if (insn->off) return 0; if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl]) { @@ -16834,8 +16805,6 @@ static int do_misc_fixups(struct bpf_verifier_env *env) } } - sort_kfunc_descs_by_imm(env->prog); - return 0; }