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 69550C433EF for ; Thu, 14 Oct 2021 20:56:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B54B61139 for ; Thu, 14 Oct 2021 20:56:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232169AbhJNU7C (ORCPT ); Thu, 14 Oct 2021 16:59:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232323AbhJNU7A (ORCPT ); Thu, 14 Oct 2021 16:59:00 -0400 Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF5D2C061755; Thu, 14 Oct 2021 13:56:54 -0700 (PDT) Received: by mail-pl1-x641.google.com with SMTP id 21so4970578plo.13; Thu, 14 Oct 2021 13:56:54 -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=TFg1pj2kMEv5NQKpZOhytoOpCWcnEzeB2F1BdFIGqrA=; b=V3tCz7SphPp1jM8kcieBLe7GsgJDNxoh2lram9QTPmiLLEtql3XjcwmnLLsTxBxpWq jImKHYBv4RPtM3PA72Mx2r+dElaMVwBjPe32LskHpj2Dao5Lt2b2KPJRPj/Pa5djAs8Z xOi2QGBoX9H+LjQlh6yeL36020jfkGy2rgp1UD0h9K2vYIjBrobYaN4d5CP7BNoucFGY xn2QPXUBUNTEHV/aMcS/GZ3fstW8XADZlMCqoI8YHPpwPFCk47SyTGxHEwnUey4mXoRi R9hhplFxMa+9LPDxdx68yBux7wJXLGdDG+MeSCIpq0ddGs8Wxe2NtJXupEHzoO3uE3Cv gKXQ== 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=TFg1pj2kMEv5NQKpZOhytoOpCWcnEzeB2F1BdFIGqrA=; b=Tljb0Wf0yGV6wZc/6Kyg1viNokvvWOf/vZI57XPUpxZokxpOWXj9mE2f5z2hPBSsbw LLX0MhyBAWiXGgJHpjeG54hKNqNxIiK1w7PrN0eRFxK7+/m19jQ+dW2AAomx9umjwPOO oeclDQAp7UPZvlaCUAOFDtTVz0uH4t13tSi9xSI2i+fNM/kwjLO2hFsS9nKh2w+Ms55w DfUVHx7wBxRzsi/Yf7g9PH33EK8XuS8M92KHdDtXjW5HKXhK8GdJVJ/yLC+qOC1bYYME /lZ5Oh9Dw9coBvnt4vMPQPpnFYhci1WdweYfmETRNIvY7uD2yQroH6fzOKLjjzdwQKhJ doKw== X-Gm-Message-State: AOAM531Vn+umOC99RIUR2o7GbL33TNM6VvcY2mwYVhig4e4MNEln1auo i+aQ96L8t/IQ9h/uMpZWgniFOVsLCh4= X-Google-Smtp-Source: ABdhPJzxYWuNSGiK5zXsVeSeyXO5iM1sRpPw9T3YgeK3H2eETKlzSFQU7iPZkIHgbBgiCBW7ZFCGew== X-Received: by 2002:a17:90b:4011:: with SMTP id ie17mr22921807pjb.41.1634245014235; Thu, 14 Oct 2021 13:56:54 -0700 (PDT) Received: from localhost ([2405:201:6014:d058:a28d:3909:6ed5:29e7]) by smtp.gmail.com with ESMTPSA id kb15sm3618655pjb.43.2021.10.14.13.56.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Oct 2021 13:56:53 -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 v3 2/8] libbpf: Add typeless ksym support to gen_loader Date: Fri, 15 Oct 2021 02:26:38 +0530 Message-Id: <20211014205644.1837280-3-memxor@gmail.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211014205644.1837280-1-memxor@gmail.com> References: <20211014205644.1837280-1-memxor@gmail.com> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=9449; h=from:subject; bh=m0wZYjjuRScwSlnlgsgoPFTKEoodhBEW8LclKvj8OLQ=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBhaJk/0KreNtnziVHvR/HH15lu7uRk+IfwZcb5S6Zn PJXz/jmJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCYWiZPwAKCRBM4MiGSL8RygvhD/ 9MgHeetWP4u4TGp9Ww+WCva34vBc/lxh3R9heY4+QtSJSs4mdX46wYLpgoVkKZiaqKNz9gOKieIdy+ Z2IBm4w9vaBicN/b101a3lSTfrbE48W0UoM1S3J5dbD/z4BnCtNEupRprQyzLJdX3AoguY+y58dGCE +mdd1ZjdNewKXPN2t/6BogKTT2IvNKrcSX9Y1MRnqRxvfx9f8NQkC9nM+Do5Slgs4LU2gOBynV2Xli /ODXEOksZmRkowf4F/BetpMc/v/b1t5Psk5daVNc/RexQQaamAAJIVSoCPGJs/ZtCcfDkrZQdK0PjO bu3lsdM+8kB23z/FoIibJOsT84pDKhY0NPxFukZOUqRDB8QFVoeONbolHu4XKSPDNVntkhqxAAX2aX Oy8O6uDtfH14IEd/oC+g/ka1Ct+kEO09kuvrOMQXtVxF49sqrGB3Fs6PaJpGfgIpKimEFdzVWvo8xe zCVMe8U2Nj9zqx1Kk6kP+lRRHxYjD8TSgb06UvBZ3qjQAkmrg7abY2T8QDrDprD3qft0uwFdJvMqK4 P756BxWzymu/JPPatQQBbE9dmeAIY7BFiLdqsnPv7EdgGnLgaVpaEnEze3+gQvS3mJhj8cuNMK/ObX 5vAnVrHnrjNUySdTKGo3FKTSmuKdkXgn+kYPLRppFYzR+d+l4GWv7JzAPAEA== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@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 ae0889bebe32..30a1a6d1b615 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; -- 2.33.0