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 1162FC4332F for ; Thu, 30 Sep 2021 06:30:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED7AE617E4 for ; Thu, 30 Sep 2021 06:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348370AbhI3Gb7 (ORCPT ); Thu, 30 Sep 2021 02:31:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348109AbhI3Gb5 (ORCPT ); Thu, 30 Sep 2021 02:31:57 -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 22516C06161C; Wed, 29 Sep 2021 23:30:15 -0700 (PDT) Received: by mail-pl1-x641.google.com with SMTP id b22so3284608pls.1; Wed, 29 Sep 2021 23:30:15 -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=pFiO3Huks5f8TvyaEQ45MpC10x4nH981N8hkRsx7UDk=; b=EXNctlVZLVG0hzLO6BLo7O1OXqz78MMjQrhZricXkRUIWJFUNjpLuEnOAxLpGF36D3 5yngcKlvvFwpTB57BqT0OCa2JdIcV7+sCgFzisf/5PsEE306dEuxPOL/XRvXOxDeu6K/ BO2gmkBOYwKpr3EYInaoNVvho7ICnN6FlnIKbwe+2ZxCAZ7p/In1yVJaEivEkS9J7BBu wJef8tfnVK4SI41/855C9LqwOZokHgVGrEo8FPrjofh2ZJu8ze+w1SQBHGBeXWZItwYe PME4zPbrcPwUje453GK9aBXph/q4EscKagJhLdyfAtw84I/vsydEbaPKqgrxNWCcVAAD Gc9A== 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=pFiO3Huks5f8TvyaEQ45MpC10x4nH981N8hkRsx7UDk=; b=6MYY9t4K87Q3ZQp+clTJlMsrR+f+DfCqRYMOWb+H//QFFivOmDQjzpZAEWiq/htkaQ j7IamRnao8W12ufMkBvI37ucJTR7WRwEVbNc6s42mt2yzqyj6iwt9dHzwzxeamKhexHR ktV4c5uIF5RFKa3zxLivI6WDIIqDSmwB0LLqF5qFRe3mhJPAvwap2LfydiMvUXv7WLKF tWGf8r8rN6qba2u9owb7JmmzmKjDv6fHpN/h6XsJ2mhnIqsg6UH1e9qXLCW5fWJWE/u9 UC1wjj0X7zaG0Vxo/pfa1WqbPXJXm+KG/++uN7aUucuFmpOQd66PHQeXmFZK/ZU8qNcU fGdw== X-Gm-Message-State: AOAM532XCv8SkgxMtJv9bfWkASgjcISLDH89caHcnx5gwHoycRmkWSjs /5zJQ5adD3wxERQa68hyDHYqtXZRm+I= X-Google-Smtp-Source: ABdhPJxjRwJxLyvd3upEFkq1LPpahbOxLmOJDpIFeKaUNSwVnMdxECdqp95w4IMilJIujfQSj7+QDA== X-Received: by 2002:a17:90a:de0b:: with SMTP id m11mr4531669pjv.90.1632983413770; Wed, 29 Sep 2021 23:30:13 -0700 (PDT) Received: from localhost ([2405:201:6014:d058:a28d:3909:6ed5:29e7]) by smtp.gmail.com with ESMTPSA id d137sm1735359pfd.72.2021.09.29.23.30.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Sep 2021 23:30:13 -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 v6 8/9] libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations Date: Thu, 30 Sep 2021 11:59:47 +0530 Message-Id: <20210930062948.1843919-9-memxor@gmail.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210930062948.1843919-1-memxor@gmail.com> References: <20210930062948.1843919-1-memxor@gmail.com> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=20037; h=from:subject; bh=cuuVy59gAX4VngY44ibc3pTwOq2crh/XFeyMU2MsINY=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBhVVlCnUHtFm3XNUFpMPH/77mQWtmSGV41FQVrmOAk DdZhN4mJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCYVVZQgAKCRBM4MiGSL8Ryh8IEA ChHEGMclyhlrM22qyx0/+uRSLtExp+nmy/x8vms/8MsyiWyhmHXjb5nT6fZuFzwiaxpsjzjk5Auyic mjOPPHgUR67CIyLTQRZHoUqB07Kd/fpw4jYgNCt4kzHz5WLEDAkvIUVGlhfmUYyH6Jd+DjSg1f5W1y YcUh/xc2FOJjO+PGzhG+UlRqAw9Zi4B2q9TVMyEhSEtOA+4Ooy4XHBqBQtSUAeEm61IyO1JIH18NBy 0CdyhUs2VVFbVw8rMQ9hCXFIJDrJT5SuYC/SB9S9ZvT2mNSRXLTCNmV2zWYYKDGxtdYE+13xJCK3It w2be+GFPVPywps0xrWByoCq2H1ABJ/R1wLwZD/leBy3v8AkSq1CxSEvb9F743wWQghb2QXErLZipWC ERz1ypn/pHva7c2zBrN5gRR5Cxdg+gxsj0MQFdjIzouRNvcKLe6J5U/ZWe+ANIbMkoT2VLi61XR+JB pKItSQoxvv7TiAcEUHa0rAzGqQziH6yvFjhHmZXAKzq4flcLrwLxIo+Or/2OG0ZU4e03ZJI48v8ZM1 lnB9NRlVhlPJl/OzP3qeSKto1sm2rBfDF7gz+PsBjz/S+lFYMs6vIuhoaKsYqoQY9OLfmWDH5Nnrb7 qyzA1iCnO4zzZGDZMnhCYITooQVQiGS66bmI9k2hEDlwyZ1xaktPr7vqeUSg== 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 change updates the BPF syscall loader to relocate BTF_KIND_FUNC relocations, with support for weak kfunc relocations. The general idea is to move map_fds to loader map, and also use the data for storing kfunc BTF fds. Since both reuse the fd_array parameter, they need to be kept together. For map_fds, we reserve MAX_USED_MAPS slots in a region, and for kfunc, we reserve MAX_KFUNC_DESCS. This is done so that insn->off has more chances of being <= INT16_MAX than treating data map as a sparse array and adding fd as needed. When the MAX_KFUNC_DESCS limit is reached, we fall back to the sparse array model, so that as long as it does remain <= INT16_MAX, we pass an index relative to the start of fd_array. We store all ksyms in an array where we try to avoid calling the bpf_btf_find_by_name_kind helper, and also reuse the BTF fd that was already stored. This also speeds up the loading process compared to emitting calls in all cases, in later tests. Signed-off-by: Kumar Kartikeya Dwivedi --- tools/lib/bpf/bpf_gen_internal.h | 16 +- tools/lib/bpf/gen_loader.c | 323 ++++++++++++++++++++++++++----- tools/lib/bpf/libbpf.c | 8 +- 3 files changed, 292 insertions(+), 55 deletions(-) diff --git a/tools/lib/bpf/bpf_gen_internal.h b/tools/lib/bpf/bpf_gen_internal.h index 615400391e57..70eccbffefb1 100644 --- a/tools/lib/bpf/bpf_gen_internal.h +++ b/tools/lib/bpf/bpf_gen_internal.h @@ -7,6 +7,15 @@ struct ksym_relo_desc { const char *name; int kind; int insn_idx; + bool is_weak; +}; + +struct ksym_desc { + const char *name; + int ref; + int kind; + int off; + int insn; }; struct bpf_gen { @@ -24,6 +33,10 @@ struct bpf_gen { int relo_cnt; char attach_target[128]; int attach_kind; + struct ksym_desc *ksyms; + __u32 nr_ksyms; + int fd_array; + int nr_fd_array; }; void bpf_gen__init(struct bpf_gen *gen, int log_level); @@ -36,6 +49,7 @@ 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, int kind, int insn_idx); +void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, int kind, + int insn_idx); #endif diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index 80087b13877f..9902f2f47fb2 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -14,8 +14,10 @@ #include "bpf_gen_internal.h" #include "skel_internal.h" -#define MAX_USED_MAPS 64 -#define MAX_USED_PROGS 32 +#define MAX_USED_MAPS 64 +#define MAX_USED_PROGS 32 +#define MAX_KFUNC_DESCS 256 +#define MAX_FD_ARRAY_SZ (MAX_USED_PROGS + MAX_KFUNC_DESCS) /* The following structure describes the stack layout of the loader program. * In addition R6 contains the pointer to context. @@ -30,7 +32,6 @@ */ struct loader_stack { __u32 btf_fd; - __u32 map_fd[MAX_USED_MAPS]; __u32 prog_fd[MAX_USED_PROGS]; __u32 inner_map_fd; }; @@ -143,13 +144,58 @@ static int add_data(struct bpf_gen *gen, const void *data, __u32 size) if (realloc_data_buf(gen, size8)) return 0; prev = gen->data_cur; - memcpy(gen->data_cur, data, size); + if (data) + memcpy(gen->data_cur, data, size); gen->data_cur += size; memcpy(gen->data_cur, &zero, size8 - size); gen->data_cur += size8 - size; return prev - gen->data_start; } +/* Get index for map_fd/btf_fd slot in reserved fd_array, or in data relative + * to start of fd_array. Caller can decide if it is usable or not. + */ +static int fd_array_init(struct bpf_gen *gen) +{ + if (!gen->fd_array) + gen->fd_array = add_data(gen, NULL, MAX_FD_ARRAY_SZ * sizeof(int)); + return gen->fd_array; +} + +static int add_map_fd(struct bpf_gen *gen) +{ + if (!fd_array_init(gen)) + return -1; + if (gen->nr_maps == MAX_USED_MAPS) { + pr_warn("Total maps exceeds %d\n", MAX_USED_MAPS); + gen->error = -E2BIG; + return -1; + } + return gen->nr_maps++; +} + +static int add_kfunc_btf_fd(struct bpf_gen *gen) +{ + int cur; + + if (!fd_array_init(gen)) + return -1; + if (gen->nr_fd_array == MAX_KFUNC_DESCS) { + cur = add_data(gen, NULL, sizeof(int)); + if (!cur) + return -1; + return (cur - gen->fd_array) / sizeof(int); + } + return MAX_USED_MAPS + gen->nr_fd_array++; +} + +static int blob_fd_array_off(struct bpf_gen *gen, int index) +{ + if (!gen->fd_array) + return 0; + return gen->fd_array + (index * sizeof(int)); +} + static int insn_bytes_to_bpf_size(__u32 sz) { switch (sz) { @@ -171,14 +217,22 @@ static void emit_rel_store(struct bpf_gen *gen, int off, int data) emit(gen, BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0)); } -/* *(u64 *)(blob + off) = (u64)(void *)(%sp + stack_off) */ -static void emit_rel_store_sp(struct bpf_gen *gen, int off, int stack_off) +static void move_blob2blob(struct bpf_gen *gen, int off, int size, int blob_off) { - emit(gen, BPF_MOV64_REG(BPF_REG_0, BPF_REG_10)); - emit(gen, BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, stack_off)); + emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE, + 0, 0, 0, blob_off)); + emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_2, 0)); emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, off)); - emit(gen, BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0)); + emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0)); +} + +static void move_blob2ctx(struct bpf_gen *gen, int ctx_off, int size, int blob_off) +{ + emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, + 0, 0, 0, blob_off)); + emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_1, 0)); + emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off)); } static void move_ctx2blob(struct bpf_gen *gen, int off, int size, int ctx_off, @@ -326,11 +380,11 @@ int bpf_gen__finish(struct bpf_gen *gen) offsetof(struct bpf_prog_desc, prog_fd), 4, stack_off(prog_fd[i])); for (i = 0; i < gen->nr_maps; i++) - move_stack2ctx(gen, - sizeof(struct bpf_loader_ctx) + - sizeof(struct bpf_map_desc) * i + - offsetof(struct bpf_map_desc, map_fd), 4, - stack_off(map_fd[i])); + move_blob2ctx(gen, + sizeof(struct bpf_loader_ctx) + + sizeof(struct bpf_map_desc) * i + + offsetof(struct bpf_map_desc, map_fd), 4, + blob_fd_array_off(gen, i)); emit(gen, BPF_MOV64_IMM(BPF_REG_0, 0)); emit(gen, BPF_EXIT_INSN()); pr_debug("gen: finish %d\n", gen->error); @@ -390,7 +444,7 @@ void bpf_gen__map_create(struct bpf_gen *gen, { int attr_size = offsetofend(union bpf_attr, btf_vmlinux_value_type_id); bool close_inner_map_fd = false; - int map_create_attr; + int map_create_attr, idx; union bpf_attr attr; memset(&attr, 0, attr_size); @@ -467,9 +521,13 @@ void bpf_gen__map_create(struct bpf_gen *gen, gen->error = -EDOM; /* internal bug */ return; } else { - emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7, - stack_off(map_fd[map_idx]))); - gen->nr_maps++; + /* add_map_fd does gen->nr_maps++ */ + idx = add_map_fd(gen); + if (idx < 0) + return; + emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, + 0, 0, 0, blob_fd_array_off(gen, idx))); + emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_7, 0)); } if (close_inner_map_fd) emit_sys_close_stack(gen, stack_off(inner_map_fd)); @@ -511,8 +569,8 @@ static void emit_find_attach_target(struct bpf_gen *gen) */ } -void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, int kind, - int insn_idx) +void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, + int kind, int insn_idx) { struct ksym_relo_desc *relo; @@ -524,38 +582,196 @@ void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, int kind, gen->relos = relo; relo += gen->relo_cnt; relo->name = name; + relo->is_weak = is_weak; relo->kind = kind; relo->insn_idx = insn_idx; gen->relo_cnt++; } -static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns) +/* returns existing ksym_desc with ref incremented, or inserts a new one */ +static struct ksym_desc *get_ksym_desc(struct bpf_gen *gen, struct ksym_relo_desc *relo) { - int name, insn, len = strlen(relo->name) + 1; + struct ksym_desc *kdesc; - pr_debug("gen: emit_relo: %s at %d\n", relo->name, relo->insn_idx); - name = add_data(gen, relo->name, len); + for (int i = 0; i < gen->nr_ksyms; i++) { + if (!strcmp(gen->ksyms[i].name, relo->name)) { + gen->ksyms[i].ref++; + return &gen->ksyms[i]; + } + } + kdesc = libbpf_reallocarray(gen->ksyms, gen->nr_ksyms + 1, sizeof(*kdesc)); + if (!kdesc) { + gen->error = -ENOMEM; + return NULL; + } + gen->ksyms = kdesc; + kdesc = &gen->ksyms[gen->nr_ksyms++]; + kdesc->name = relo->name; + kdesc->kind = relo->kind; + kdesc->ref = 1; + kdesc->off = 0; + kdesc->insn = 0; + return kdesc; +} + +/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7} + * Returns result in BPF_REG_7 + */ +static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_desc *relo) +{ + int name_off, len = strlen(relo->name) + 1; + name_off = add_data(gen, relo->name, len); + if (!name_off) + return; emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, - 0, 0, 0, name)); + 0, 0, 0, name_off)); emit(gen, BPF_MOV64_IMM(BPF_REG_2, len)); emit(gen, BPF_MOV64_IMM(BPF_REG_3, relo->kind)); emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0)); emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind)); emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0)); debug_ret(gen, "find_by_name_kind(%s,%d)", relo->name, relo->kind); - emit_check_err(gen); +} + +/* Expects: + * BPF_REG_8 - pointer to instruction + * + * We need to reuse BTF fd for same symbol otherwise each relocation takes a new + * index, while kernel limits total kfunc BTFs to 256. For duplicate symbols, + * this would mean a new BTF fd index for each entry. By pairing symbol name + * with index, we get the insn->imm, insn->off pairing that kernel uses for + * kfunc_tab, which becomes the effective limit even though all of them may + * share same index in fd_array (such that kfunc_btf_tab has 1 element). + */ +static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn) +{ + struct ksym_desc *kdesc; + int btf_fd_idx; + + kdesc = get_ksym_desc(gen, relo); + if (!kdesc) + return; + /* try to copy from existing bpf_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 + offsetof(struct bpf_insn, off), 2, + kdesc->insn + offsetof(struct bpf_insn, off)); + goto log; + } + /* remember insn offset, so we can copy BTF ID and FD later */ + kdesc->insn = insn; + emit_bpf_find_by_name_kind(gen, relo); + if (!relo->is_weak) + emit_check_err(gen); + /* get index in fd_array to store BTF FD at */ + btf_fd_idx = add_kfunc_btf_fd(gen); + if (btf_fd_idx < 0) + return; + if (btf_fd_idx > INT16_MAX) { + pr_warn("BTF fd off %d for kfunc %s exceeds INT16_MAX, cannot process relocation\n", + btf_fd_idx, relo->name); + gen->error = -E2BIG; + return; + } + kdesc->off = btf_fd_idx; + /* set a default value for imm */ + emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0)); + /* skip success case store if ret < 0 */ + emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, 1)); /* store btf_id into insn[insn_idx].imm */ - insn = insns + sizeof(struct bpf_insn) * relo->insn_idx + - offsetof(struct bpf_insn, imm); + emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm))); + /* load fd_array slot pointer */ emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE, - 0, 0, 0, insn)); - emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, 0)); - if (relo->kind == BTF_KIND_VAR) { - /* store btf_obj_fd into insn[insn_idx + 1].imm */ - emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32)); - emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, - sizeof(struct bpf_insn))); + 0, 0, 0, blob_fd_array_off(gen, btf_fd_idx))); + /* skip store of BTF fd if ret < 0 */ + emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, 3)); + /* store BTF fd in slot */ + emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_7)); + emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32)); + emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0)); + /* set a default value for off */ + emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0)); + /* skip insn->off store if ret < 0 */ + emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, 2)); + /* skip if vmlinux BTF */ + emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_9, 0, 1)); + /* store index into insn[insn_idx].off */ + emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), btf_fd_idx)); +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, + offsetof(struct bpf_insn, off))); + debug_regs(gen, BPF_REG_7, BPF_REG_9, " func (%s:count=%d): imm: %%d, off: %%d", + relo->name, kdesc->ref); + emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE, + 0, 0, 0, blob_fd_array_off(gen, kdesc->off))); + emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_0, 0)); + debug_regs(gen, BPF_REG_9, -1, " func (%s:count=%d): btf_fd", + relo->name, kdesc->ref); +} + +/* Expects: + * BPF_REG_8 - pointer to instruction + */ +static void emit_relo_ksym_btf(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 BTF ID and FD later */ + kdesc->insn = insn; + emit_bpf_find_by_name_kind(gen, relo); + emit_check_err(gen); + /* store btf_id into insn[insn_idx].imm */ + emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm))); + /* store btf_obj_fd into insn[insn_idx + 1].imm */ + emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32)); + 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); +} + +static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns) +{ + int insn; + + pr_debug("gen: emit_relo (%d): %s at %d\n", relo->kind, relo->name, relo->insn_idx); + insn = insns + sizeof(struct bpf_insn) * relo->insn_idx; + 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); + break; + case BTF_KIND_FUNC: + emit_relo_kfunc_btf(gen, relo, insn); + break; + default: + pr_warn("Unknown relocation kind '%d'\n", relo->kind); + gen->error = -EDOM; + return; } } @@ -571,14 +787,22 @@ static void cleanup_relos(struct bpf_gen *gen, int insns) { int i, insn; - for (i = 0; i < gen->relo_cnt; i++) { - if (gen->relos[i].kind != BTF_KIND_VAR) - continue; - /* close fd recorded in insn[insn_idx + 1].imm */ - insn = insns + - sizeof(struct bpf_insn) * (gen->relos[i].insn_idx + 1) + - offsetof(struct bpf_insn, imm); - emit_sys_close_blob(gen, insn); + for (i = 0; i < gen->nr_ksyms; i++) { + if (gen->ksyms[i].kind == BTF_KIND_VAR) { + /* 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 */ + 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--; + } + } + if (gen->nr_ksyms) { + free(gen->ksyms); + gen->nr_ksyms = 0; + gen->ksyms = NULL; } if (gen->relo_cnt) { free(gen->relos); @@ -637,9 +861,8 @@ void bpf_gen__prog_load(struct bpf_gen *gen, /* populate union bpf_attr with a pointer to line_info */ emit_rel_store(gen, attr_field(prog_load_attr, line_info), line_info); - /* populate union bpf_attr fd_array with a pointer to stack where map_fds are saved */ - emit_rel_store_sp(gen, attr_field(prog_load_attr, fd_array), - stack_off(map_fd[0])); + /* populate union bpf_attr fd_array with a pointer to data where map_fds are saved */ + emit_rel_store(gen, attr_field(prog_load_attr, fd_array), gen->fd_array); /* populate union bpf_attr with user provided log details */ move_ctx2blob(gen, attr_field(prog_load_attr, log_level), 4, @@ -706,8 +929,8 @@ void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue, emit(gen, BPF_EMIT_CALL(BPF_FUNC_copy_from_user)); map_update_attr = add_data(gen, &attr, attr_size); - move_stack2blob(gen, attr_field(map_update_attr, map_fd), 4, - stack_off(map_fd[map_idx])); + move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4, + blob_fd_array_off(gen, map_idx)); emit_rel_store(gen, attr_field(map_update_attr, key), key); emit_rel_store(gen, attr_field(map_update_attr, value), value); /* emit MAP_UPDATE_ELEM command */ @@ -725,8 +948,8 @@ void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx) memset(&attr, 0, attr_size); pr_debug("gen: map_freeze: idx %d\n", map_idx); map_freeze_attr = add_data(gen, &attr, attr_size); - move_stack2blob(gen, attr_field(map_freeze_attr, map_fd), 4, - stack_off(map_fd[map_idx])); + move_blob2blob(gen, attr_field(map_freeze_attr, map_fd), 4, + blob_fd_array_off(gen, map_idx)); /* emit MAP_FREEZE command */ emit_sys_bpf(gen, BPF_MAP_FREEZE, map_freeze_attr, attr_size); debug_ret(gen, "map_freeze"); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a750ee5d8035..0f85d441fca3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6339,12 +6339,12 @@ static int bpf_program__record_externs(struct bpf_program *prog) ext->name); return -ENOTSUP; } - bpf_gen__record_extern(obj->gen_loader, ext->name, BTF_KIND_VAR, - relo->insn_idx); + bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, + BTF_KIND_VAR, relo->insn_idx); break; case RELO_EXTERN_FUNC: - bpf_gen__record_extern(obj->gen_loader, ext->name, BTF_KIND_FUNC, - relo->insn_idx); + bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, + BTF_KIND_FUNC, relo->insn_idx); break; default: continue; -- 2.33.0