From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 099ECC433F5 for ; Wed, 20 Oct 2021 19:15:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6B9361355 for ; Wed, 20 Oct 2021 19:15:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231546AbhJTTRx (ORCPT ); Wed, 20 Oct 2021 15:17:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231547AbhJTTRu (ORCPT ); Wed, 20 Oct 2021 15:17:50 -0400 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E6158C06161C; Wed, 20 Oct 2021 12:15:35 -0700 (PDT) Received: by mail-pj1-x1043.google.com with SMTP id np13so3157207pjb.4; Wed, 20 Oct 2021 12:15:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=/xOkhz61QTrrkVnzjwqrnCLH/AVH6ZL40FhPK1vDeTk=; b=fTZBTFFL4Jl2W2duP0QsAaiRjGc3RDWuSmvT0whe1Vz9+jhI3QJu9le8GRfMPoUKzj IzvvCPjb7/Cxci5A6Jb3tlIn2Jxo1Bq5s312YneO1qww3R5dzmwMTX5oVo5Ezc9RfAxa Bj6UnjEiVN0/MicSqLZC0uLPr8G6z9/bb0levGhayqszRdKKXLxAWEHKGtY9F7bUO5CZ vgqSvqmVc+vbXTBq1qoAFSvFfrFuK4LmhYeEqvMTgTI3li4pGKtP6FZVxEFAYeMyP+ol QE9gZkKinPTVVT7wauXeWLf+woBZADhQXo8JnPwIPAjE68uTEl/E6wv4H+PV3xbN8Dh9 8FYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=/xOkhz61QTrrkVnzjwqrnCLH/AVH6ZL40FhPK1vDeTk=; b=BkLO9OiYo/tpRfMSoH5YyiK8TXzBvSGrYPodZC+/3e/TDdPiVzjmhUDtQWlxeDl7AD 3RClR8zULxFOxq+veJgbA9QI6xqS+jsAy1WTP7TMSwrD1ptmONtlY1eemYXsbWAdkwvu 5LtQbmpD0DqlJK9MhirI0YKn/fFq5pbnsvXX8E3GQlr2KxsXbywfCzA5H0/sQwkrxXJF +uQbIPMxU4lRdblRAiFZPEQCg6DROL/l4u9u3f22e3i3jnFt/GabFuRCz7r0zR3xEq4T JsPqKPdQac0pK+nj9mAUX/fPH/NZoId9Dz1YQqUOP/Z8YNSXDzHBElrHJW9CRT+72Gnm JDjw== X-Gm-Message-State: AOAM530xYOCb2NuYMQGI9pWGxwYTu84jYH0SutipS5LaBJcsfpr5f9Dr ZFc9T/FHgkB+ojekunSFdbaRTQYzlpY4Ag== X-Google-Smtp-Source: ABdhPJw8EMXQEXFtnK4WZFUI0VKM2ID+7uDU8eAdSe5HBca+uYZqFb5AbTfTrFaKA1BxsV7EoOOisg== X-Received: by 2002:a17:90a:760a:: with SMTP id s10mr945912pjk.135.1634757335164; Wed, 20 Oct 2021 12:15:35 -0700 (PDT) Received: from localhost ([2405:201:6014:d058:a28d:3909:6ed5:29e7]) by smtp.gmail.com with ESMTPSA id s2sm7489705pjs.56.2021.10.20.12.15.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Oct 2021 12:15:34 -0700 (PDT) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , Jesper Dangaard Brouer , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , netdev@vger.kernel.org Subject: [PATCH bpf-next v4 2/8] libbpf: Add typeless ksym support to gen_loader Date: Thu, 21 Oct 2021 00:45:20 +0530 Message-Id: <20211020191526.2306852-3-memxor@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211020191526.2306852-1-memxor@gmail.com> References: <20211020191526.2306852-1-memxor@gmail.com> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=9449; h=from:subject; bh=+/ip5hQm9vqRjnJqxrpS1vvXOvCk9UzcyXdVKQpyXSI=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBhcGoeJdpnY0+/ayubk9l4UpS/rAI+NkKREFntFXbP mSFKm9aJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCYXBqHgAKCRBM4MiGSL8RysyYD/ sGcWMLJvkcmFZxxHiqL/hpVtl/lfv4p8Wd98hVkyjdz7wL4WKtyK8KBiph29dwGgDaFyoJoguCcsXm L9RDAgKb/P+JYGsUtBI3GM09keZa1lHVfvip80eH3jnmPBtOGu+ZDmi3pphQQqDC7BREFtCaxqX+wS w52hE3nHZXAaCb8Uf/UAmPP8gwHVV8FTt+IU/WVleWzHaiXf+RVyaKHIcNq4m6CT3j+LqYI7dXxhc1 sluzssLjiLJCLldn/Ji8fycWHuI0IGBbcWK3Sh/B2Np7PGvUwIlSjefC5TVo5FrhutDrpZZjAmcK0s SEhb0P38otSJKGafMKhOgLj6gj+gxe9vMw4ZhXAaPd89l6KVz5C3A4m54JxrKNd+THfere0axFNi4e 7G3f8fJflrKgrUF6WMK0RGYRVBpb9KFA5k+XTy7N4zHf2ljQpKCd6P9iHJFjX7lI5t3fbOMSwPgZ+P 41qwbSD1NtcLWRgfaHDqNSzpb810RV3ey55Y4NySL+6Akm1OoF3NnimkQRS9In5920cG7sN6tv0zW5 CYfuMXTuYeAAFDWzwSr+JgCZY9zYOYUFfB4dg99UZU7eUTCS6n7tjJUCkGvV5lpyvL9oS4qIvA69gQ jdvLP5F/XyaCsicpqm8uU7/r2OVzWjkmG0CEWA6Qa6+DbNvmpoZ94zwO0J5w== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This uses the bpf_kallsyms_lookup_name helper added in previous patches to relocate typeless ksyms. The return value ENOENT can be ignored, and the value written to 'res' can be directly stored to the insn, as it is overwritten to 0 on lookup failure. For repeating symbols, we can simply copy the previously populated bpf_insn. Also, we need to take care to not close fds for typeless ksym_desc, so reuse the 'off' member's space to add a marker for typeless ksym and use that to skip them in cleanup_relos. We add a emit_ksym_relo_log helper that avoids duplicating common logging instructions between typeless and weak ksym (for future commit). Signed-off-by: Kumar Kartikeya Dwivedi --- tools/lib/bpf/bpf_gen_internal.h | 12 +++- tools/lib/bpf/gen_loader.c | 97 ++++++++++++++++++++++++++++---- tools/lib/bpf/libbpf.c | 13 ++--- 3 files changed, 99 insertions(+), 23 deletions(-) diff --git a/tools/lib/bpf/bpf_gen_internal.h b/tools/lib/bpf/bpf_gen_internal.h index 70eccbffefb1..9f328d044636 100644 --- a/tools/lib/bpf/bpf_gen_internal.h +++ b/tools/lib/bpf/bpf_gen_internal.h @@ -8,13 +8,19 @@ struct ksym_relo_desc { int kind; int insn_idx; bool is_weak; + bool is_typeless; }; struct ksym_desc { const char *name; int ref; int kind; - int off; + union { + /* used for kfunc */ + int off; + /* used for typeless ksym */ + bool typeless; + }; int insn; }; @@ -49,7 +55,7 @@ void bpf_gen__prog_load(struct bpf_gen *gen, struct bpf_prog_load_params *load_a void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *value, __u32 value_size); void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx); void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *name, enum bpf_attach_type type); -void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, int kind, - int insn_idx); +void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, + bool is_typeless, int kind, int insn_idx); #endif diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index 937bfc7db41e..11172a868180 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -559,7 +559,7 @@ static void emit_find_attach_target(struct bpf_gen *gen) } void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, - int kind, int insn_idx) + bool is_typeless, int kind, int insn_idx) { struct ksym_relo_desc *relo; @@ -572,6 +572,7 @@ void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, relo += gen->relo_cnt; relo->name = name; relo->is_weak = is_weak; + relo->is_typeless = is_typeless; relo->kind = kind; relo->insn_idx = insn_idx; gen->relo_cnt++; @@ -621,6 +622,29 @@ static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_des debug_ret(gen, "find_by_name_kind(%s,%d)", relo->name, relo->kind); } +/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7} + * Returns result in BPF_REG_7 + * Returns u64 symbol addr in BPF_REG_9 + */ +static void emit_bpf_kallsyms_lookup_name(struct bpf_gen *gen, struct ksym_relo_desc *relo) +{ + int name_off, len = strlen(relo->name) + 1, res_off; + + name_off = add_data(gen, relo->name, len); + res_off = add_data(gen, NULL, 8); /* res is u64 */ + emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, + 0, 0, 0, name_off)); + emit(gen, BPF_MOV64_IMM(BPF_REG_2, len)); + emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0)); + emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_4, BPF_PSEUDO_MAP_IDX_VALUE, + 0, 0, 0, res_off)); + emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_4)); + emit(gen, BPF_EMIT_CALL(BPF_FUNC_kallsyms_lookup_name)); + emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0)); + emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0)); + debug_ret(gen, "kallsyms_lookup_name(%s,%d)", relo->name, relo->kind); +} + /* Expects: * BPF_REG_8 - pointer to instruction * @@ -700,6 +724,58 @@ static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo relo->name, kdesc->ref); } +static void emit_ksym_relo_log(struct bpf_gen *gen, struct ksym_relo_desc *relo, + int ref) +{ + if (!gen->log_level) + return; + emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8, + offsetof(struct bpf_insn, imm))); + emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) + + offsetof(struct bpf_insn, imm))); + debug_regs(gen, BPF_REG_7, BPF_REG_9, " var t=%d w=%d (%s:count=%d): imm[0]: %%d, imm[1]: %%d", + relo->is_typeless, relo->is_weak, relo->name, ref); + emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code))); + debug_regs(gen, BPF_REG_9, -1, " var t=%d w=%d (%s:count=%d): insn.reg", + relo->is_typeless, relo->is_weak, relo->name, ref); +} + +/* Expects: + * BPF_REG_8 - pointer to instruction + */ +static void emit_relo_ksym_typeless(struct bpf_gen *gen, + struct ksym_relo_desc *relo, int insn) +{ + struct ksym_desc *kdesc; + + kdesc = get_ksym_desc(gen, relo); + if (!kdesc) + return; + /* try to copy from existing ldimm64 insn */ + if (kdesc->ref > 1) { + move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4, + kdesc->insn + offsetof(struct bpf_insn, imm)); + move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4, + kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)); + goto log; + } + /* remember insn offset, so we can copy ksym addr later */ + kdesc->insn = insn; + /* skip typeless ksym_desc in fd closing loop in cleanup_relos */ + kdesc->typeless = true; + emit_bpf_kallsyms_lookup_name(gen, relo); + emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_7, -ENOENT, 1)); + emit_check_err(gen); + /* store lower half of addr into insn[insn_idx].imm */ + emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, offsetof(struct bpf_insn, imm))); + /* store upper half of addr into insn[insn_idx + 1].imm */ + emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32)); + emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm))); +log: + emit_ksym_relo_log(gen, relo, kdesc->ref); +} + /* Expects: * BPF_REG_8 - pointer to instruction */ @@ -729,14 +805,7 @@ static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm))); log: - if (!gen->log_level) - return; - emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8, - offsetof(struct bpf_insn, imm))); - emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) + - offsetof(struct bpf_insn, imm))); - debug_regs(gen, BPF_REG_7, BPF_REG_9, " var (%s:count=%d): imm: %%d, fd: %%d", - relo->name, kdesc->ref); + emit_ksym_relo_log(gen, relo, kdesc->ref); } static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns) @@ -748,7 +817,10 @@ static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn)); switch (relo->kind) { case BTF_KIND_VAR: - emit_relo_ksym_btf(gen, relo, insn); + if (relo->is_typeless) + emit_relo_ksym_typeless(gen, relo, insn); + else + emit_relo_ksym_btf(gen, relo, insn); break; case BTF_KIND_FUNC: emit_relo_kfunc_btf(gen, relo, insn); @@ -773,12 +845,13 @@ static void cleanup_relos(struct bpf_gen *gen, int insns) int i, insn; for (i = 0; i < gen->nr_ksyms; i++) { - if (gen->ksyms[i].kind == BTF_KIND_VAR) { + /* only close fds for typed ksyms and kfuncs */ + if (gen->ksyms[i].kind == BTF_KIND_VAR && !gen->ksyms[i].typeless) { /* close fd recorded in insn[insn_idx + 1].imm */ insn = gen->ksyms[i].insn; insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm); emit_sys_close_blob(gen, insn); - } else { /* BTF_KIND_FUNC */ + } else if (gen->ksyms[i].kind == BTF_KIND_FUNC) { emit_sys_close_blob(gen, blob_fd_array_off(gen, gen->ksyms[i].off)); if (gen->ksyms[i].off < MAX_FD_ARRAY_SZ) gen->nr_fd_array--; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 760c7e346603..02cd7a6738da 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6355,17 +6355,14 @@ static int bpf_program__record_externs(struct bpf_program *prog) case RELO_EXTERN_VAR: if (ext->type != EXT_KSYM) continue; - if (!ext->ksym.type_id) { - pr_warn("typeless ksym %s is not supported yet\n", - ext->name); - return -ENOTSUP; - } - bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, + bpf_gen__record_extern(obj->gen_loader, ext->name, + ext->is_weak, !ext->ksym.type_id, BTF_KIND_VAR, relo->insn_idx); break; case RELO_EXTERN_FUNC: - bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, - BTF_KIND_FUNC, relo->insn_idx); + bpf_gen__record_extern(obj->gen_loader, ext->name, + ext->is_weak, false, BTF_KIND_FUNC, + relo->insn_idx); break; default: continue; -- 2.33.1